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REFERENCE TO RELATED APPLICATIONS
This application is a continuation of copending U.S. patent application Ser. No. 07/772,974 filed Oct. 8, 1991, U.S. Pat. No. 5,141,419, which is a division of U.S. Pat. No. 5,067,883 issued Nov. 26, 1991, which, in turn, is a continuation of U.S. patent application Ser. No. 07/239,688 filed Sep. 2, 1988, now abandoned, which in turn is a continuation in part application of U.S. patent application Ser. No. 098,189 filed Sep. 17, 1987 now abandoned. U.S. patent application Ser. No. 098,189 was continued as Ser. No. 07/349,873 filed May 9, 1989, now U.S. Pat. No. 5,024,590 issued Jun. 18, 1991
THIS INVENTION relates broadly to the art of ROTARY MECHANISMS and more particularly relates to the art of ROTARY INTERNAL COMBUSTION ENGINES, including all types of vehicles and equipments or apparatus provided with Rotary Internal Combustion Engines, and or Rotary Equipments/Machines such as Rotary Compressors, Rotary Pumps, Rotary Cutting Tools, or lathes as well as Rotary Systems for Aircraft Engines, or any future flying craft, using any kind of fuels suitable for such Rotary Internal Combustion Engines, either for land, sea or air transportations, and for the other special purposes, which hereinafter for the purpose of simplicity will be referred to as ROTARY ENGINE.
BACKGROUND OF THE INVENTION
Rotary engines of the above mentioned type are comprised of an outer component having axially spaced end walls and a periphery curved or parallel to the axis and an inner component having axially spaced end surfaces and a periphery curved or parallel to the axis, which components hereafter for simplicity will be referred to as the housing and the rotor which housing defines a cavity having an epicyclic shape for a two apex rotor or in the shape of a two lobed epitrochoidal cavity housing for a three apex rotor.
Normally in such a rotary engine, there is an internal ring gear which is eccentrically mounted on the main crankshaft. The internal ring gear is fixed or secured within one side of the rotor and intermeshed to a pinion gear having a hollow shaft for free wheeling within the said main crankshaft. Particularly for a rotary engine with a three apex rotor the gearing ratio of the internal ring gear: pinion gear is fixed at 3:2 for which thereafter the pinion has to be fixed or secured to the housing frame. Such gearing ratio as mentioned above therefore will limit the diameter size of the main crankshaft due to the given eccentricity of such design.
Such fixing of the pinion as mentioned above to the housing frame kinematically will cause the power transmitted to be dependent on the strength of the cavity wall against the strong pressures of the rotor which receives the powerful impact as caused by the expanding gases soon after every ignition/combustion, particularly during extreme conditions when the engine is in operations. Sooner or later such conditions will cause an excessively heavy wear along the contact lines between the cavity wall and the rotor, which in the end will course shorten the life or durability of the said engines.
Such rotor having axially spaced end surfaces and a peripheral wall parallel to the axis which hereafter for the purpose of simplicity will be referred to as the rotor with flat outer surface or flat rotor, will cause what is called "corner seal leakage" which is considered as one of the most serious problems to be solved due to is geometrical conditions.
By such limited size of the main crankshaft, fixing the pinion gear to the housing frame, and corner sealing, the whole performance of this typical rotary engine has been characterized by widely known, relatively low efficiency, high fuel consumption, high emissions, and excessive wear etc.
SUMMARY OF THE INVENTION
The objects of the present invention are to provide a new system for eliminating all said above low performances by using a larger pinion gear, to allow a larger diameter size of main crankshaft rotating the said pinion gear to allow direct power transmission to the main crankshaft and therefore avoiding the excessive wear along the contact lines between the rotor and the cavity wall, and by using radially curved apex rotor portions as well as a radially arcaded housing cavity wall, between which will be inserted suitable sealing elements which are able to eliminate the corner sealing problems which occur in the conventional models.
Those methods above objects are achieved by the rotary engine of the invention which instead of installing intermeshing gears as described in applicant's previous application (European Patent application No. 87.201780.1 and U.S. patent application Ser. No. 098,189, now abandoned in favor of continuation application Ser. No. 07/349,873, now U.S. Pat. No. 5,024,590) a planetary gears system or epicyclic gears train will be installed between the rotor and the main crankshaft to secure and fix the speed ratio of 1:3 or 1:2 as required in order to maintain the permanent and stable or constant clearance between the rotor and the housing cavity wall during all relative rotations. Such permanent, stable or constant clearance as mentioned above will avoid any direct contact of the rotor to the housing cavity wall particularly during extreme conditions of engine operation.
In such preferred embodiment, the arms of the planetary gears system or epicyclic gears train will be constructed integral to the pinion gear so therefore the planetary gears system is able to control the speed ratio of the rotor and the main crankshaft to 1:2 for a two apex rotor with an epicyclic housing cavity and 1:3 for a three apex rotor with two lobed epitrochoid housing cavity. Unlike the conventional design, in which the pinion gear is fixed and secured to the housing frame and therefore the pinion will always stay at its stationary position, in this invention the pinion will rotate or is rotated according to an intercorrelation speed among the gears, and therefore will be able to prevent any possibilities that a strong dynamic force during any extreme condition may cause the rotor to press the cavity wall in order to transmit the power to the main crankshaft of the engine, which of course would cause the wearing. The pinion rotation is fixed to a fractional figure of 1/4 for a two apex rotor and 1/9 for a three apex rotor, which means that the pinion will rotate or is rotated up to 90° for every 360° main crankshaft rotation of the two apex rotor engine and up to 40° for every 360° main crankshaft rotation of the three apex rotor engine, by which rotation thereafter the rotor will obtain its proper speed. Based on the said above constructions therefore is it now made possible to use a larger internal ring gear which will be fixed or secured to one side of the rotor. Such ring rear as mentioned above for the two apex rotor will be constructed to a gearing ratio of 3:2 with its intermeshing pinion gear, and for the three apex rotor, will be constructed to a gearing ratio of 4:3 with its intermeshing pinion gear, which based on said above gearing ratio thereafter it is possible to use a larger size of main crankshaft diameter for better and stronger performances. Based on the above-mentioned construction, it is therefore made possible to use when necessary such i.e. for internal combustion engines, a radially curved apex rotor portion with a curved shape which extends continuously from one to an adjacent apex and which curved shape becomes minimal in the middle of said two adjacent apices. Such radially curved apex rotor shape is not necessary if such construction is used for compressors, pumps, cutting tools, etc.
In the case of internal combustion engines, within the outer surface of the said radial curve of the three apex rotor will be constructed a channel between each of the two adjacent curved apices in order to obtain the proper compression ratio as may be required by the manufacturer, while within each radially curved apex portion of the rotor there will be provided sufficient grooves for suitable rings or sealing element installation seats i.e. such as beveled or normal grooves. If so desired, such channels used in the case of a three apex rotor engine, need not be used for the two apex rotor engine's construction, because for the same purpose, the curve of the two apex rotor outer surface can be adjusted to provide a suitable compression ration.
It is further object of the invention that particularly the two apex rotor engines will be provided with inlet and exhaust valves driven by one or more cam shafts having a speed ratio of 1:4 against the main crankshaft rotations. Accordingly, because such an effective clearance between the cooperating shapes of the radially curved apex rotor and the radially arcaded housing cavity wall is now made possible by the invention, which clearance is constantly and permanently maintained during all relative rotations of the rotor, the said sealing element will function properly and prevent any leakage of the compression from one working chamber into another working chamber as a result of its own spring power, which therefore can maintain the permissible normal wearing rate for durability of such engines. In connection with the said above matter, the invention contemplates the use of a chrome plated inner radially arcaded housing cavity wall as well as for the sealing rings, for the purpose of obtaining smooth and hard chromed surfaces which have a good affinity for lubricating oil and which reduce the sealing ring wearing rate significantly.
Particularly for the three apex rotor, the present invention has a further object to provide that either a curved or flat rotor, instead of being constructed to have three apices with three lobed outer surfaces, is constructed to have three apices with six lobed outer surfaces. This construction will enable the said three apex rotor to fully wipe out completely the remaining volume of compressed fluid or gases into the outlet passage within the housing cavity and thereafter the same outer surfaces will receive a new volume of fluid or gases from the inlet passage adjacent to the mentioned above outlet passage, to be brought forward into the suction chamber and compression chamber respectively.
When this construction of the invention is applied to internal combustion engines, the invention contemplates that the same channel as previously described will be constructed between each two adjacent apices for the purpose of adjusting the compression ratio as it may be required by manufacturer, which channel of course will still cause the remaining burned gases to be brought forward and mixed further with the new inserted air-fuel through the adjacent inlet passage.
It is further object of the invention that for rotary engines using either a two or three apex rotor, a planetary gears system or epicyclic gears train will be installed between the rotor and its main crankshaft.
The said planetary gears system or epicyclic gears train normally consist of three different gears such as the sun, the planet and the static outer ring gear. The sun gear is the gear in the center part of the system, while the planet is the intermeshed gear between the static ring gear and the said sun gear, and rotates in an opposite direction with respect to the main crankshaft and therefore enables the arm of the planet gears to rotate in the same direction as the main crankshaft. In these specific constructions, the invention contemplates that the arm of the planet gears will be constructed integral with the pinion gear which is intermeshed to the internal ring gear fixed within one side of the rotor, while the sun gear will be fixed or secured to the main crankshaft i.e. by such involute spline gear. By said above mentioned constructions therefore, the main crankshaft rotations are now integrated to the rotor's rotations and the gearing ratio is fixed to the proper required gearing ratio necessary to reach the speed ratio as previously mentioned, such as 1:2 for a two apex rotor and 1:3 for a three apex rotor. For the two apex rotor having in internal ring gear and its pinion based on a gearing ratio of 3:2, the suitable planetary gears system of epicyclic gears train will be constructed so that the sun, the planet and the static outer ring gear will be fixed according to the gearing ratio of 1:1:3.
By such construction therefore the arm of the planet gears will be rotated or rotates 90° per every 360° revolution of the main crankshaft.
For the three apex rotor having an internal ring gear and its pinion based on a gearing ratio of 4:3, the suitable planetary gears system or epicyclic gears train will be constructed so that the sun, the planet and the static outer ring gear will be fixed according to the gearing ratio of 1:1:8, so therefore the arm of the planet gears will be rotated or rotates 40° per 360° main crankshaft rotation. But because a gearing ratio of 1:8 between the sun and the static outer ring gear is not practical if constructed, therefore the invention contemplates that the planet gear as it may be required, instead of constructing it based on a gearing ratio of 1:1 with the sun gear or 1:8 with the static outer ring gear, in this matter will be constructed in a "cluster gear assembly" consisting of two integrated smaller and larger gears, of which the smaller is intermeshed to the ring gear based on ratio of 1:4, and the larger intermeshed to sun gear to the ratio 1:2. By such construction therefore, the arm of the planet gears will be rotated or rotates 40° per each 360° revolution of the main crankshaft.
Kinematically only one intermeshing gear is required as the planet gear, but by using three gears, there will be more balance available and the loads can be equally divided among the gears and therefore will make possible the utilization of smaller or thinner gears for the system.
Therefore, the planetary gears system or epicyclic gears train as mentioned above has more advantages compared to the intermeshing gears, including particularly stable rotations, centering accuracy, simple constructions, etc.
It is further object of the invention to provide that particularly for the radially curved apex rotor with radially arcaded housing cavity, the housing cavity construction will be made in two or more parts either crossing or parallel to the axis shaft depending on the variation as it may be necessary, provided with proper gasket or rubber or any other suitable sealing as to prevent any possibilities of compression leakage, cooling water leakage as well as any lubricating oil leakage from one working chamber into another.
In connection with the housing cavity construction either for the radially curved apex portion or flat surface rotor, the invention contemplates that in order to obtain the correct and precision shape which is the same as the outer envelope of the rotor based on a speed ratio of 1:3 to the main crankshaft for the three apex rotor, or a speed ratio 1:2 to the main crankshaft for the two apex rotor, except for the permissible or allowed clearance as will be determined by the manufacturer, a special cutting tool which is constructed based on the same principles as the engine but provided with an accurate size cutting blade fixed or secured to the said too, will be used to precisely cut and form the inner housing cavity.
Similar cutting tools, especially for a three apex rotor with six lobed outer surfaces, either of radially curved or flat type, are also made possible by using the same principles, but unlike the cutting tools for the housing cavity which cut while rotating to the proper speed ratio, the cutting tools for this typical rotor are constructed stationary.
For the preferred embodiment, the invention has further particular objects to provide the engines with the same gearing principles such as the gears for internal ring gear, the pinion, the intermeshing gears trains well as the planetary gears system or epicyclic gears trains, but to be based on different gearing ratio, which will be determined or result from the computation of the formula described in our previously submitted applications (European Patent application No. 87.201780.1 and U.S. patent application Ser. No. 098,189, now abandoned in favor of continuation application Ser. No. 07/349,873, now U.S. Pat. No. 5,024,590) as follows: ##EQU1## in which : I.I.G.P. refers to the pitch diameter of the internal involute gear pinion.
I.I.G. refers to the pitch diameter of the internal involute gear.
a/b designates the additional rotation of the internal involute gear on each rotation of the main crankshaft, and
P designates the basic ratio of the specific type of rotary engine, being 1/2 for the rotary engine using a two apex rotor and epicyclic housing cavity, and 2/3 for the rotary engine using a three apex rotor and a two lobed epitrochoid housing cavity.
In connection with the above mentioned formula, the invention contemplates that the gearing ratio of the intermeshing gears train can be determined based on computations as follows:
a/b=I.I.G.P./I.I.G.×c/d×e/f
in which c/d and e/f designate the gearing ratio of the intermeshing gears, and in case more gears are required in order to obtain the right ratio, such computation can be extended to: a/d=I.I.G.P./I.I.G.×c/d×e/f×g/h.
Further objects and features of the invention will be apparent from the following descriptions of the preferred embodiments with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal section view of the rotary engine having a radially curved two apex rotor, and a radially arcaded housing cavity and intermeshing gears in between.
FIG. 2 is a cross sectional view, partly taken on the line I--I and partly taken on the line II--II of the FIG. 1.
FIG. 3 are details illustrating motion of the two apex rotor with epicyclic housing.
FIG. 4 shows the two units of a two apex rotor combined in one engine.
FIG. 5 and 6 illustrate the planetary gears system applied to a rotary engine having a two curved apex rotor and a curved epicyclic housing cavity.
FIG. 7 is a longitudinal section view of a rotary compressor based on the invention principles, having planetary gears system applied for a two, flat apex rotor and epicyclic housing cavity, specially designed for a car air conditioning system.
FIG. 8 is the longitudinal section view of the special cutting tools to shape the housing cavity.
FIGS. 9 and 10 are respectively a schematic side view and an axial cross sectional view of the planetary gears system applied to a rotary engine having a three, curved apex rotor and a curved two lobed epitrochoid housing cavity.
FIG. 11 is a schematic illustration of the rotations of the apex portion shown in the FIG. 12 based on the speed ratio of 1:3 to the main crankshaft.
FIG. 12 is a cross sectional view of the rotary engine having a three apex rotor with six lobed outer surfaces and a two lobed epitrochoid housing cavity.
FIG. 13 shows the exact positions of the curved apex portion of the rotor during all relative rotations based on the speed ratio of 1:3 to the main crankshaft.
FIG. 14 is the perspective view of the radially curved three apex rotor provided with intermeshing gears system based on the principles of the invention.
FIG. 15 is a perspective view of the whole engine unit with portions shown in silhouetted and broken away in which can be seen the radially curved three apex rotors (2 units) and their housing cavities based on the principles of the invention and provided with an intermeshing gears system.
FIGS. 16 a, b, c and d are the drawings of the relative motions of the related parts in accordance with the kinematic description of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, a rotary internal combustion engine according to this invention is provided with two rotor units each having two radially curved apices 21 and being located within a curved housing cavity 20. The rotors are each mounted to an eccentric hubshaft 23 made and constructed integral with the main crankshaft 24, to have free wheeling by means of metal bearings 22 between the rotor and the eccentric hubshafts 23 and between the main crankshaft and the housing frame 25.
Each rotor is provided with side seal elements 27 which are connected with apex seal elements 28 and lubricating oil scraper rings 26 and 29. The curved housing cavity is provided with inlet and outlet passages 30 which are controlled by means of valves 31 supported by coil springs 32 and which valves are driven by means of camshaft 36 and rocker arms 33 and connecting rods 34.
The engine is also provided with ignitions by means of spark plugs 35 which are fixed or secured to the housing frame 20. The housing frame has a supporting main body which also functions as lube-oil tank 39.
For the cooling system, the housing frame is provided with cooling water passages 40 which are conventionally constructed.
Within one side of the rotor 21 there is fixed or secured an internal ring gear 37 which is intermeshed to a pinion gear 38 with a gearing ratio of 3:2. The pinion gear 38 is made or constructed in an integral cluster gears assembly with gear 47 having a hollow shaft for free wheeling around the main crankshaft 24 by means of roller bearings 41.
The gear 47 is intermeshed with a gear 51 which is made or constructed in another cluster gears assembly with the gear 52 having a separate shaft 42. The gearing ratio between gear 47 and 51 is fixed at 2:1.
The gear 52 is intermeshed to a final pinion gear 48 which is fixed or secured to the main crankshaft 24 by means of involute spline and strengthened by means of special locknut 49, and the gears 52 and 48 have a gearing ratio of 2:1. The cluster gears assembly shaft 42 is provided with a bearing 43 within which an end of the shaft is mounted to the housing frame 20 and gear cover 50. Both ends of the main crankshaft 24 are mounted with ball bearings 44, a lube-oil seal 46 and a seal cover 45 to prevent any lube-oil leakage out of the engine. As shown in the FIG 3 the detailed motion of the rotor 21, within the housing cavity 20 is precisely drawn based on the speed ratio of 1:2 between the rotor and the main crankshaft 24.
The housing cavity 20 of an epicyclic form, and the permanent or constant clearance between the rotor apex 21 and the housing cavity 20 is therefore made possible by such constructions.
FIG. 4, shows the exact position of each rotor as drawn in the FIGS. 1 and 2, at the same time and at the eccentric hubshaft distance of 180° between each other.
In this particular design the front rotor 21 with apex sealing element 28 is mounted to the eccentric hubshaft 23 through bearings 22 with the main crankshaft 24 driving at a speed ratio of 1:2.
Because the rear eccentric hubshaft is positioned at a distance of 180° to the front eccentric hubshaft, for balanced rotations and ignitions the housing cavity of the rear part is constructed higher than the front part due to the given eccentricity.
Such condition will cause the inlet and outlet passages of the front part 30/I to be relatively higher than the inlet and outlet passages of the rear part 30/II, while the rear housing cavity 20/II is relatively higher than the front housing cavity 20/I.
FIGS. 5 and 6 show the planetary gears system or epicyclic gears train used for the same radially curved two apex rotors 21 with radially arcaded housing cavity 20.
In this construction, the sun gear 348 which is fixed or secured to the main crankshaft 324, is intermeshed to three units of planet gears 362 which are each mounted to an armshaft 361 for free wheeling, based on a gearing ratio of 1:1.
The three units of planet gears 362 are also intermeshed to the outer ring gear of 359 based on a gearing ratio of 1:3.
So therefore, because of the superposition of the planet gears, the reduction of the arm 360 speed ratio will be 1:(3/1+1) =1:4 or equal to 90° per each 360° revolution of the main crankshaft. And by a gearing ratio of 2:3 between the pinion gear 38 and internal ring gear 37, the rotor 21 will be rotated or rotates up to (12/3)×360°=12020 . As the arm is integrated to the pinion by a gearing ratio of 2:3, the internal ring gear will be rotated or rotates to 2/3×90°=60°as additional rotation per each main crankshaft 360+ rotation. By adding the additional rotation of 60° to its own rotation of 120° therefore the rotor 21 will have totally 120 °+60°=180° per each 360° main crankshaft rotation, which is exactly according to the speed ratio of 1:2 as required by such two apex rotor and epicyclic housing cavity.
FIG. 7 is a rotary compressor based on the invention principles and designed for a car air conditioning system to the actual size of 1:1 to show how small and effective the invention is for such particular purpose.
Such compressor is constructed to have a two apex rotor 421 with flat outer surfaces provided with proper sealing elements 427. Within the rotor 421 there is constructed from the same material as the rotor an integral internal ring gear 437 which is intermeshed to a pinion gear 438, based on a gearing ratio of 2:3.
Such rotor 421 is mounted to an eccentric hubshaft made integrally with the main crankshaft 424, for free wheeling through a roller bearing 422 installed therebetween.
The pinion gear 438 is made integral with the arm of planet gears 460 which are constructed to hold an armshaft 461 where planet gears 462 will free wheel around.
The sun gear is fixed or secured to the main crankshaft by means of an involute spline and intermeshed to the three units or planet gears based on a gearing ratio of 1:1. The three units of planet gears are also intermeshed to an outer ring gear 459 which is fixed and secured to the housing frame.
By such construction therefore the arm will be rotated or rotates 90° per each revolution of the main crankshaft 424, so that the rotor will rotate 60° additional rotation per each revolution of the main crankshaft in order to obtain a speed ratio of 1:2.
The main crankshaft 424 is also provided with lubricating oil holes 453 through the center for sufficient lubrication of a roller bearing 441 which is installed within the hollow shaft of the pinion gear 438, and also to lubricate a rotating seal assembly formed of a coil spring 457, a carbon seal 446/C, a stationary seal seat and rubber gasket 458, and a retaining ring 459. Both sides of the main crankshaft 424 are respectively, firmly mounted to a front ball bearing 444/F and a rear ball bearing 444/R with a snap ring 459'. The opening in the engine which receives the crankshaft 424 is closed by end cover 445 after sufficient special lube-oil is provided therein. In a front part of the engine a balance counterweight 464 is fixed and secured to the main crankshaft 424 by means of a locknut 449.
Within the outer part of the housing there is fixed a magnetic field coil 471, and a free wheeling pulley seat assembly 472 which is positioned on a cylindrical roller bearing 456 to cooperate with a clutch assembly 455.
The cylindrical roller bearing is fixed and secured to the housing frame by means of a special locknut 460, while the clutch assembly is fixed and secured to the main crankshaft 424 by means of a front hexagonal nut 465.
In the rear part, the compressor is provided with schrader 454 and within the inside part thereof there is installed a cylindrical plate valve 463.
FIG. 8 shows a special cutting tool made for the purpose of cutting or precisely shaping the radially arcaded housing cavity or flat inner surface either for a two apex rotor or a three apex rotor.
Such equipment according to the invention includes a rotor 221 provided with a cutting blade of the same shape as the desired housing cavity. The cutting blade 254 is fixed or secured by means of bolt and nut 255. The rotor 221 is mounted to the eccentric hubshaft 223 which is integral with the main crankshaft 224, and rotated to the speed ratio of 1:2 for the two apex rotor or a speed ratio of 1:3 for the three apex rotor, by means of intermeshing gears 237 and 238, 247 and 251, 252 and 248, in such a way in accordance to each gearing ratio as it may be required for each type of engine.
In such a construction the main crankshaft 224 is held by two ball bearings 244 which in the front part are connected to a pinion locknut 249 and at the rear are closed by a hex nut.
To drive the cutting tools a pulley 253 is installed in between the two bearings and fixed to the main crankshaft 224 by means of inserted key 256. The ball bearings are positioned to the sides of the main frame 257 which is also constructed to accommodate one side of the separate hubshaft of the cluster gears assembly 242. The other side of hubshaft 242 is supported by a special separate stand 258 which is fixed or secured to the main frame by means of bolts and nuts.
FIGS. 9 and 10 are the drawings of the planetary gears system applied to the rotary engine having a curved three apex rotor 21 and a two lobed curved epitrochoid housing cavity 20. The planet gears according to this invention are constructed in a cluster gears assembly consisting of a smaller gear 362/I and a larger gear 362/II, which is intermeshed with sun gear 348 as well as to the outer ring gear 359 based on a gearing ratio between gear 348 and 362/II fixed at 1:2 and between gear 362/I and ring gear 359 fixed at 1:4. The said sun gear is fixed to the main crankshaft by means of involute spline and strengthened by means of special locknut 349.
Because of the superposition of the planet gears, therefore the arm 360 will be reduced in its speed to the ratio of 1:(2/1 ×4/1) +1=1:9 or equal to 40° per each 360° revolution of the main crankshaft.
By giving the ratio of 3:4 between pinion gear 38 and internal ring gear 37, therefore the rotor 21 will be rotated or rotates up to (1-3/4)×360°=90° on each revolution of the main crankshaft. The rotation of the arm of 40° as mentioned above will cause the rotor to be given an additional rotation by pinion gear 38 up to 3/4×40°=30° per each revolution of the main crankshaft. Therefore by adding its own rotation of 90° with the said additional rotation of 30° the rotor will rotate to 90°+30°=120° per each revolution of the main crankshaft, which is exactly according to the speed ratio of 1:3 as required by such typical rotary engine having a three apex rotor and a two lobed epitrochoid housing cavity.
FIG. 12 is the drawing of the typical rotary engine having a three apex rotor with a six lobed outer surfaces and a two lobed epitrochoid housing cavity. The rotor is fixed at a speed ratio of 1:3 with the main crankshaft which motion can be seen from FIG. 11.
By such construction it is now made possible to obtain a wider space within the apex portion to cooperate with the cavity wall for leakage prevention.
FIG. 13 is an illustration of the exact position of the apex rotor at a speed ratio of 1:3. For the same size of rotor compared to the conventional design with stationary pinion gear fixed to the housing frame, this typical design has a shorter eccentricity as well as shorter horizontal length of line c4 - b2 as shown in the FIG. 13. FIG. 14 is a perspective drawing of the rotor provided with intermeshing gears in accordance with the invention.
FIG. 15 is a perspective drawing of the whole concept of the invention based on a silhouetted broken away view to show the rotor 121, radial apex seal 128, curved housing 120, side seal elements 127, internal ring gear 137, pinion gear 138, the intermeshing gears 147, 148, 151 and 152, the main crankshaft 124 and eccentric hubshaft 123, flywheel 164, inlet passage 166, outlet passage 165 and lube oil tank 195, oil filter 190, cooling fan 180, electric generator 170, etc.
FIGS. 16 a, b, c and d are drawings for the following kinematic description.
KINEMATICS OF THE INVENTION
FIGS. 16 a, b, c and d show the kinematic of the preferred embodiment of the invention, in which rotary engine, and I.I.G./Internal Involute Gear (400) is fixed to the rotor (200) and intermeshed to an I.I.G.P./Internal Involute Gear Pinion (500) having a hollow shaft, through which a M.C.S./Main Crankshaft (100) including its integral E.H./Eccentric Hub Shaft (150) will rotate freely.
In FIG. 6c the I.I.G.P. (500) is intermeshed with an I.I.G. (400) based on a gearing ratio of 2:3. The I.I.G.P. (500) has a hollow shaft through which the M.C.S. (100) can rotate freely.
In such a case the I.I.G.P. (500) is fixed or secured to its housing frame as conventionally constructed.
Based on such gearing ratio of 2:3, therefore every revolution (360°) of the M.C.S. (100)/E.H.S.(150), the rotor (200)I.I.G. (400) will be rotated or rotates to (1-2/3)×360°=120°, which means the speed ratio between the rotor (200)/I.I.G. (400) against the M.C.S. (100)/E.H.S.(150) is 120°:360°=1:3. The contact points of the both pitch circles are a point c which belong to the pitch circle of I.I.G.(400) and a point P which belongs to the pitch circle of I.I.G.P. (500).
In FIG. 16a the M.C.S. (100)/E.H.S. (500) is rotated to 90° (<α=90°) and therefore the center point of E.H.S. (150) which is 03 will move to 03 1 .
Because the I.I.G.P. (500) is stationary, therefore point P will still be at its original position while the point C will move to new position of C 62 (<α=1/3×<α=30°).
In FIG 16b, the I.I.G.P. (500) is intermeshed with I.I.G. (400) based on gearing ratio of 3:4 and the I.I.G.P. (500) is still fixed or secured to its housing frame. By such gearing ratio of 3:4, therefore with every revolution of M.C.S. (100)/E.H.S. (150) the rotor (200)/I.I.G. (400) will be rotated or rotates to: (1-3/4)×360°=90°, in this FIG. 16b, because the M.C.S. (100)/E.H.S. (150) is rotated only for 90°. Therefore point C will move to point C.sup.φ, and point P is still maintained in its original position (<φ=1/4×<α=22.5°).
But because the speed ratio of the rotor (100) must be maintained 1:3 if using a three apex portion rotor with a two lobed epitrochoid housing cavity, therefore the new position of point C must be in the point Cβ (<β=30°).
The distance between C 100 and C 62 in this FIG. 16b can be reached only by the rotor (200)/I.I.G. (400) if during the said above rotation it is accelerated through the intermeshing gears installed between the rotor (200) and the M.C.S. (100) by which intermeshing gears, therefore the rotor (200) will always be able to reach in due time and the accurate position of Cβ on each revolution as mentioned above. Such additional distance of Cφ to Cβ if mentioned in fractional figures is designated as a/b in the Raser formula in the said application.
In FIG. 16b the distance to C 100 to C 62 is 30°-22.5°=7.5°per 90° of the shaft rotation. Therefore if calculated by a complete revolution of 360° the same said above distance will be (360°:90°)×7.5°=30°or represent 1/12 of shaft revolution. Therefore in such a case as mentioned in FIG 16b and a/b quotient is equal 1/12 which equation has been used and described in the previous Summary of the Invention of the previous application (E.P.O. No. 87.201780.1, U.S. Pat. No. 5,024,590). the said above a/b equation is designed for the purpose of maximum use of the space available and minimum bearing to be installed in the engine.
There are many variations in determining the gearing ratio for such same purpose but only few that can save the space and minimum gearing as mentioned above. If the Raser formula is not used to calculate the gearing as explained above, there is the possibility that the a/b quotient can not be met precisely by any combinations of gears installed, and therefore consequently will cause the outer envelope of the rotor's rotation to have a shape which is not exactly the same as the two lobed epitrochoid housing cavity and which will not be able to maintain the permanent clearance during all relative rotations between each apex portion of the rotor (200) and the housing wall (11). Such permanent clearance during all relative rotation is made possible only if the rotor (200) always maintains the speed ratio of 1:3 with its M.C.S. (100).
Furthermore, the invention is also applicable to any other rotary type such as a two apex rotor or a four apex rotor, which for the purpose of simplicity the basic ratio for the specific type of rotary (such as 1/2 for a two apex rotor, 2/3 for a three apex rotor and 3/4 for a four apex rotor, hereinafter will be designated or referred to as p respectively, as can be seen from the formula of this invention.
The intermeshing gears which are installed between the rotor (200)/I.I.G. (400) and the M.C.S. (100) will cause the I.I.G.P. (100) to rotate in the same direction in order that the point of C 100 reaches the position of the point C 62 based on speed ratio of 1:2 for a two apex rotor, or 1:3 for a three apex rotor or 3:4 for a four apex rotor.
The movement of the I.I.G.P. (100) is shown in the FIGS. 16c and 16d. In FIG. 16c, the I.I.G.P. (500) is constructed in one hollow shaft with one of the intermeshing gears through which it will be rotated or rotates according to its proper speed ratio.
Because the a/b quotient of 1/12 represents for such rotary engine with I.I.G.P. (500) and I.I.G. (400) having a gearing ratio of 3:4, therefore the I.I.G.P. (500) will be rotated or rotates to the distance of:
1/12×4/3×360°=40° per each full revolution of the M.C.S. (100) / E.H.S. (1500 or in fractional figure of 1/9.
Such fractional figure of 1/9 can be easily split into 1/3×1/3 which means that the further intermeshing gears between the I.I.G.P. (500) and M.C.S. (100) is fixed to gearing ratio of 1:3 and 1:3 respectively (minimum gears for space efficiency). In FIG. 16c because the M.C.S. (100) is rotated only for 90° therefore the new position of the P will be P1 which is 90°/360°×40°=10° in the same direction and the actual P position after every full revolution will be P2 which is at 40° away from its original position.
In a rotary engine with a two apex rotor and a one epicyclic housing cavity the figure if 1/4 which can be easily split into fixed gearing ratio of 1:2 and 1:2 respectively while in a three apex rotor with a four lobed epitrochoid housing it will be 1/16 which can be easily split into fixed gearing ratio of 1:4 and 1:4 respectively.
Because based on the above gearing ratio of 3:4 between the I.I.G.P. (500) and its intermeshing I.I.G. (400) the diameter of the M.C.S. (100) can be constructed larger than the conventional model.
Such larger M.C.S. (100) other than the conventional model can be seen from the FIG. 16d, by which, naturally the engine will be able to carry more loads etc.
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A rotary internal combustion engine, including all types of vehicles and equipments or apparatus provided with such rotary engines, or machines which principally consist of a two, three or four, either radially curved or flat, apex rotor and a radially arcaded or curved epicyclic or two or three lobed epitrochoid housing cavity, in which construction such rotary engine, the rotor (21 of FIG. 1), has its rotations integrated with the rotations of the main crankshaft (24 of FIG. 1), through the intermeshing gears train (37, 38, 37, 48, 51, 52 of FIG. 1) or through the planetary gears system or epicyclic gears train (324, 348, 459, 360, 361, 362 of FIGS. 5 and 6 and 362/I, 362/II of FIGS. 9 and 10) by which rotor will be rotated or rotates in accordance to its specific basic speed ratio (such as 1:2 for bi-apex rotor, 1:3 for tri-apex rotor, etc.) so thereafter the rotor will rotate with an effective clearance during all relative rotations and therefore is able to maintain such permanent distance between the cooperating shapes of the stationary outer components or the housing and the rotating inner component or the rotor, which distance will be used for inserting proper sealing elements, which because of its radially curved geometrical nature, it is therefore able to seal the working chambers precisely and eliminate any of the so called corner seal leakages which commonly occur in the conventional models, beside also being able to avoid any possibility of direct contact between the rotor apex portions and the inner housing cavity wall.
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FIELD OF THE INVENTION
[0001] The present invention relates to an airbag fabric and a preparation method for the same, and more particularly to a polyester fabric, a preparation method for the same, and an airbag for vehicle comprising the same, where the polyester fabric uses a polyester fiber having low Young's modulus, high strength, and high elongation to impart good mechanical properties, such as high strength and high thermal resistance.
BACKGROUND OF THE INVENTION
[0002] Generally, an airbag refers to a vehicle safety device for providing protection to the occupants during a frontal vehicle collision at an impact speed of about 40 km/h or above by deploying explosive chemicals to generate a gas and inflate the airbag cushion upon sensing a crash with a crash impact sensor. The structure of a general airbag system is as illustrated in FIG. 1 .
[0003] As shown in FIG. 1 , a general airbag system comprises an airbag module 100 mounted in the steering wheel and containing an inflator 121 for generating gas upon ignition triggered by a detonator 122 , and an airbag 124 being inflated by the gas to spread out toward the driver; an impact sensor 130 for generating impact signals in the event of a collision; and an electronic control module 110 for igniting the detonator 122 of the inflator 121 upon receiving the impact signals. In the event of a frontal collision, the impact sensor 130 in the airbag system senses collision impacts to send impact signals to the electronic control module 110 . Upon recognition of the impact signals, the electronic control module 110 triggers the detonator 122 to ignite the gas generator propellant in the inflator 121 . The ignited gas generator propellant rapidly generates a gas to inflate an airbag 124 . Being inflated to unfold, the airbag collides with the driver's chest to partly absorb the impact load caused by the vehicle collision. Inertia causes the driver's head and chest move toward to collide with the airbag 124 , in which case the gas of the airbag 124 rapidly exits through the exhaust holes formed in the airbag 124 to cushion the driver's head and chest. In this manner, the airbag system effectively relieves impacts on the driver in the event of a frontal collision to reduce the risk of secondary injuries.
[0004] It is therefore of a great importance to secure flexibility for reducing impacts on the occupants as well as good mechanical properties, such as low air permeability to facilitate airbag unfolding, and high strength and high thermal resistance to prevent damage or rupture of the airbag, folding property, with a view to effectively maintaining folding and packing properties of the airbag when installed into a vehicle, preventing damage or rupture of the airbag, acquiring high unfolding performance of the airbag cushion and minimizing impacts on the occupants. In fact, there have never been suggested airbag fabrics capable of maintaining air sealing effect and flexibility for the occupant's safety, sufficiently enduring impacts on the airbag, and being packed into a vehicle effectively.
[0005] Conventionally, polyamide fibers such as nylon 66 have been used as a material for airbag fabric. Despite high impact resistance, nylon 66 is inferior to polyester fibers in regard to resistance to heat and humidity, light resistance, and dimensional stability, and more expensive.
[0006] Japanese Patent Publication No. Hei 04-214437 discloses the use of a polyester fiber overcoming these problems. However, the use of the conventional polyester fiber in the manufacture of an airbag leads to difficulty in packing the airbag into a small space in a vehicle due to extremely high stiffness, excessive thermal shrinkage during heat treatment at high temperature due to high elasticity and low elongation, and limitations in maintaining good mechanical properties and unfolding performance under severe conditions of high temperature and high humidity.
[0007] Accordingly, there is a need for developing a fabric capable of maintaining good mechanical properties and air sealing effect to be suitable for use in airbags for vehicle and providing good properties, such as high thermal resistance to endure heat treatment at high temperature, high flexibility to reduce impacts on occupants, and good packing property.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide a polyester fabric having good mechanical properties, such as high strength and high thermal resistance, high flexibility, and good packing property.
[0009] It is another object of the present invention to provide a method for preparing the polyester fabric.
[0010] It is still another object of the present invention to provide an airbag for vehicle comprising the polyester fabric.
[0011] To achieve the objects of the present invention, there is provided a polyester fabric having a thermal resistance constant (X) of 1.0 to 6.5 as defined by the following calculation formula 1 when the fabric is uncoated:
[0000] Thermal resistance constant( X )=( T×t )/(600 ×D ) [Calculation Formula 1]
[0012] In the calculation formula 1, T is the temperature of a hot rod during free fall in the range of 350 to 750° C.; t is the amount of time (sec) taken for the hot rod to pass through the polyester fabric from a point of contact with the polyester fabric; and D is the thickness (mm) of the polyester fabric.
[0013] There is also provided a method for preparing the polyester fabric that comprises: weaving a polyester fiber into a grey fabric for airbag; scouring the grey fabric for airbag; and tentering the scoured fabric.
[0014] Further, there is provided an airbag for vehicle comprising the polyester fabric.
[0015] Hereinafter, a detailed description will be given as to a polyester fabric, a preparation method for the same, and an airbag for vehicle comprising the same in accordance with specified embodiments of the present invention, which are given by way of illustration only and not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that various changes and modifications are available to the embodiments within the scope of the present invention.
[0016] Unless stated otherwise, the terms “comprises”, “comprising”, “includes” and/or “including” as used herein specify the presence of stated elements (or components) without any specific limitations but do not preclude the addition of other elements (or components).
[0017] The term “airbag fabric” as used herein refers to a woven or nonwoven fabric used in the manufacture of airbags for vehicle. The airbag fabrics used in common include a plain woven fabric of Nylon 6 which is woven with a Rapier spinning machine, or a nonwoven fabric of Nylon 6. But, the airbag fabric of the present invention uses a polyester fiber and thus features good mechanical properties, such as high toughness, high tear strength, etc.
[0018] To use a polyester fiber as an airbag fiber instead of a polyamide fiber such as Nylon 66 that has been used in the prior art, it is required to overcome the problems in association with the use of the polyester fiber, including deterioration of the folding property resulting from high Young's modulus and high stiffness of the polyester fiber, deterioration of the mechanical properties pertaining to low melting heat capacity (ΔH), and the consequent deterioration of the unfolding performance.
[0019] Compared with Nylon, the polyester fiber exhibits higher stiffness due to its specific molecular structure and thus features higher Young's modulus. Hence, the use of the polyester fiber in an airbag fabric which is folded into a vehicle leads to drastic deterioration of the packing property. Further, the carboxyl end group (hereinafter, referred to as “CEG”) in the polyester molecular chain attacks the ester bond under severe conditions of high temperature and high humidity to break the molecular chain apart, deteriorating the properties with the progress of aging.
[0020] Accordingly, the present invention can improve the properties when applied as an airbag fabric by using a polyester fiber having low Young's modulus, high strength and high elongation and thereby optimizing the thermal resistance constant of the polyester fiber, to secure good mechanical properties and air sealing performance and remarkably reduce the stiffness.
[0021] Particularly, a series of experiments carried out by the inventors of the present invention have revealed that the use of a polyester fabric having defined characteristics in preparing an airbag fabric enables the airbag fabric to maintain good mechanical properties (e.g., high strength and high thermal resistance), air leak protecting performance, packaging performance, etc. under severe conditions of high temperature and high humidity and enhances folding property, dimensional stability, and air sealing effect, thereby securing more enhanced packing properties when the fabric used as an airbag fabric is packed into a vehicle.
[0022] In accordance with one embodiment of the present invention, there is provided a polyester fabric having defined characteristics. Such a polyester fabric has a thermal resistance constant (X) of 1.0 to 6.5 as defined by the following calculation formula 1 when the fabric is uncoated:
[0000] Thermal resistance constant( X )=( T×t )/(600 ×D ) [Calculation Formula 1]
[0023] In the calculation formula 1, T is the temperature of a hot rod during free fall in the range of 350 to 750° C. (degree celsius); t is the amount of time (sec) taken for the hot rod to pass through the polyester fabric from a point of contact with the polyester fabric; and D is the thickness (mm) of the polyester fabric.
[0024] From the results of a series of experiments, the inventors of the present invention have found it out that the use of a specific polyester fabric having an optimized thermal resistance constant in a defined range can provide an airbag fabric capable of effectively absorbing and enduring energy of the high temperature high pressure gas. More specifically, the “uncoated” polyester fabric before the coating process has a thermal resistance constant (X) of 1.0 to 6.5, preferably 1.1 to 5.8, and thus can be used as an airbag fabric very effectively.
[0025] The term “thermal resistance constant” as used herein refers to the retention time taken for a hot rod to pass through the polyester fabric based on the thickness of the polyester fabric, as defined by the calculation formula 1, and represents the thermal resistance index of the airbag fabric under high-temperature conditions. The thermal resistance constant is a random value varying depending on the material of the airbag fabric, and used to make simulation predicting how much an airbag fabric can endure the instantaneous high temperature high pressure gas ejected from the inflator in the event of airbag unfolding. The higher melting heat capacity ΔH of the polyester fabric for airbag leads to the higher thermal resistance of the polyester fabric.
[0026] Particularly, the lower thermal resistance of the polyester fabric deteriorates the thermal resistance of the fabric to endure the high temperature high pressure gas ejected from the inflator upon airbag unfolding, so the airbag fabric using the polyester fabric is susceptible to rupture or thermal bonding. Hence, the polyester fabric of the present invention cannot be used as an airbag fabric, when the thermal resistance constant is less than 1.0 for the uncoated fabric before the coating process using a rubber component. The extremely high thermal resistance constant of the polyester fabric leads to an extremely high degree of crystallization, thereby concentrating stress on crystals to deteriorate the mechanical properties of the airbag fabric, such as tensile strength and tear strength. Thus when the thermal resistance constant is greater than 6.5 for the uncoated polyester fabric before the coating process using a copper component, the polyester fabric can hardly secure sufficient mechanical properties as an airbag fabric.
[0027] For the polyester fabric of the present invention not coated with a rubber component, the thermal resistance constant X as defined by the calculation formula 1 is 1.20 to 3.5, preferably 1.28 to 3.0 when the temperature T of the hot rod is 450° C.; and 1.0 to 2.0, preferably 1.05 to 1.8 when the temperature T of the hot rod is 600° C. Further, the thermal resistance constant X as defined by the calculation formula 1 is 4.2 to 6.0, preferably 4.4 to 5.7 when the temperature T of the hot rod is 350° C.; and 1.0 to 1.8, preferably 1.1 to 1.5 when the temperature T of the hot rod is 750° C.
[0028] The polyester fabric for airbag according to the present invention may comprise a rubber coating layer, which is applied on the surface of the polyester fabric by coating or lamination. The rubber-coated polyester fabric may have a thermal resistance constant X of 2.8 to 17.0, preferably 3.0 to 16.5.
[0029] The rubber component as used herein includes at least one selected from the group consisting of powdered silicone rubber, liquid silicone rubber, polyurethane, chloroprene, neoprene rubber, and emulsion type silicone resin. The type of the rubber component for the coating layer is not specifically limited to those substances listed above, but the silicone coating is desirable with a view to eco-friendliness and mechanical properties.
[0030] The coating weight per unit area of the rubber coating layer is 20 to 200 g/m 2 , preferably 20 to 100 g/m 2 . More specifically, the coating weight is preferably 30 to 95 g/m 2 for OPW (One Piece Woven) type side curtains or airbag fabrics, and 20 to 50 g/m 2 for plain woven airbag fabrics.
[0031] For the polyester fabric comprising a rubber coating layer, the thermal resistance constant X as defined by the calculation formula 1 is 3.3 to 10.0, preferably 3.5 to 9.5 when the temperature T of the hot rod is 450° C.; and 3.0 to 7.0, preferably 3.2 to 6.5 when the temperature T of the hot rod is 600° C. Further, the thermal resistance constant X as defined by the calculation formula 1 is 9.5 to 17.0, preferably 10.0 to 16.5 when the temperature T of the hot rod is 350° C.; and 2.8 to 6.0, preferably 3.0 to 5.8 when the temperature T of the hot rod is 750° C.
[0032] According to a preferred embodiment of the present invention, the thermal resistance constant can be determined with a hot rod tester as illustrated in FIG. 2 . In the hot rod tester, the hot rod is heated up to 350 to 750° C., preferably 380 to 720° C. and arranged to drop from the above the fabric. The hot rod in a state of free fall is dropped down to the polyester fabric. The period of time taken for the hot rod to completely pass through the polyester fabric from the point of contact with the fabric is measured and applied to the calculation formula 1 based on the thickness of the polyester fabric to calculate the thermal resistance constant of the polyester fabric.
[0033] In one preferred embodiment of the present invention, the hot rod can be placed above the polyester fabric at a distance “d” of about 60 to 85 mm. The hot rod as used herein is made of a metal or ceramic material having a thermal conductivity of 40 to 70 W/m·K and a weight of 35 to 65 g.
[0034] The thickness of the polyester fabric, as measured according to the ASTM D 1777 method, is 0.18 to 0.43 mm, preferably 0.25 to 0.38 mm in view of securing good packing and folding properties when the airbag is packed into a vehicle, as well as good mechanical properties and good air sealing performance. Further, the thickness of the polyester fabric may be 0.18 mm or greater mm in consideration of the tear strength and the air sealing performance of the airbag cushion; and 0.43 mm or less considering the folding property of the airbag cushion.
[0035] In the airbag fabric of the present invention, the polyester fabric may comprise a polyester fiber having different values of fineness. The fineness of the polyester fiber may have an influence on the optimum range of the thermal resistance constant to secure good mechanical properties and high thermal resistance for the airbag fabric using the polyester fiber. Preferably, the polyester fabric may comprise a polyester fiber having a fineness of 400 to 650 denier. The polyester fiber may have a fineness of 400 to 650 denier in order to maintain low fineness and high strength in consideration of the folding property of the air cushion and the absorption performance to absorb the high temperature high pressure energy generated during airbag unfolding. Preferably, the polyester fiber has a fineness of 400 denier or greater in consideration of the energy absorption performance; and 650 denier or less with a view to providing good folding property for the air cushion.
[0036] The polyester fabric for airbag according to the present invention has a toughness of 3.5 to 6.0 kJ/m 3 , preferably 3.8 to 5.7 kJ/m 3 , where the toughness is defined by the following calculation formula 2:
[0000] Toughness(work of rupture)=∫ 0 strain F·dl [Calculation Formula 2]
[0037] In the calculation formula 2, F denotes the load applied when the length of the polyester fiber or fabric is increased by dl; and dl is the increment of the length of the polyester fiber or fabric.
[0038] Compared with the conventional fabrics, the polyester fabric has a higher level of toughness (work of rupture) and thus more effectively absorbs the energy of high temperature high pressure gas. The term “toughness” as used herein is defined as the amount of energy that the fabric can absorb before rupturing under the tensile force, and also defined as the resistance to an instantaneous impact. When the length of a fiber is increased from 1 to 1+dl under load F, the work is F·dl, and the toughness required to break the fiber is given by the calculation formula 2. In other words, the toughness is given by the area underneath the strength-elongation curve of the fiber or the fabric. The fabric exhibits higher toughness with an increase in the strength and elongation of the fiber used to form the fabric. Particularly, the airbag fabric with low toughness is susceptible to rupture, because the low toughness results in low resistance to the instantaneous unfolding impact from the inflator under high temperature high pressure conditions in the event of airbag unfolding. Accordingly, the fabric of the present invention of which the toughness is, for example, below 3.5 kJ/m 3 is unsuitable for use as an airbag fabric.
[0039] Further, the airbag fabric of the present invention concentrates the stress when inflated by an instantaneous great force from the high temperature and high pressure gas during airbag unfolding and thus exhibits a high level of tear strength. The tear strength indicates the amount of force required to rupture the airbag fabric and is measured according to the ASTM D 2261 TONGUE method. The tear strength of the airbag fabric is 18 to 30 kgf for an uncoated fabric not comprising a separate rubber coating layer; and 30 to 60 kgf for a coated fabric. In this regard, the tear strength of the airbag fabric below the lower limit of the defined range, that is, less than 18 kgf for an uncoated fabric or less than 30 kgf for a coated fabric leads to a rupture of the airbag during unfolding, consequently with a risk of airbag malfunction. On the other hand, the tear strength of the airbag fabric above the upper limit of the defined range, that is, greater than 30 kgf for an uncoated fabric or greater than 60 kgf for a coated fabric leads to lower edge comb resistance of the fabric, abruptly deteriorating air sealing performance during airbag unfolding.
[0040] Generally, a polyester fiber has such a molecular structure that imparts higher stiffness than nylon fibers or the like, consequently with higher Young's modulus, so the use of the polyester fiber for an airbag fabric leads to considerable deterioration of folding and packing properties to make the airbag fabric difficult to pack into a small space of a vehicle. Accordingly, the present invention uses a polyester fiber with high strength and low Young's modulus to maintain the toughness and tear strength of the fabric and greatly reduce the stiffness of the fabric. The airbag fabric of the present invention has a stiffness of 1.5 kgf or less, or 0.2 to 1.5 kgf, preferably 0.3 to 1.2 kgf, more preferably 0.4 to 0.8 kgf, where the stiffness is measured according to the ASTM D 4032 method. Like this, the airbag fabric of the present invention having a remarkably low stiffness relative to the conventional polyester fabric can acquire good folding property, high flexibility, and enhanced packing property while being packed into a vehicle.
[0041] To be used for airbags, the fabric of the present invention preferably has a stiffness maintained in the defined range. An extremely low stiffness of the fabric cannot secure supportive and protective functions when the airbag is inflated to unfold; while an extremely high stiffness of the fabric may reduce dimensional stability and thus deteriorate packing property when the airbag is packed into the vehicle. Further, the desirable stiffness of the fabric is 1.5 kgf or less, particularly, 0.8 kgf or less for a fineness below 460 denier, and 1.5 kgf or less for a fineness of 550 denier or greater, with a view to preventing deterioration of the packing property due to difficulty of folding the extremely stiff fabric, and avoiding discoloration of the fabric.
[0042] The static air permeability of the uncoated airbag fabric of the present invention (as measured according to the ASTM D 737 method) is 10.0 cfm or less, preferably 0.3 to 8.0 cfm, more preferably 0.5 to 5.0 cfm when ΔP is 125 pa; and 14 cfm or less, preferably 4 to 12 cfm when ΔP is 500 pa. Further, the dynamic air permeability of the uncoated airbag fabric (as measured according to the ASTM D 6476 method) is 1,700 mm/s or less, preferably 200 to 1,600 mm/s, more preferably 400 to 1,400 mm/s. The term “static air permeability” as used herein refers to the quantity of air penetrating into the airbag fabric under a predetermined pressure. The static air permeability decreases with a decrease in the filament fineness (denier per filament) of the fiber and an increase in the density of the fabric. The term “dynamic air permeability” as used herein refers to the quantity of air penetrating into the airbag fabric under an average instantaneous differential pressure of 30 to 70 kPa. In the same manner of the static air permeability, the dynamic air permeability decreases with a decrease in the filament fineness of the fiber and an increase in the density of the fabric.
[0043] By including a rubber coating layer, the airbag fabric can have a considerably reduced air permeability, approximating to 0 cfm. Due to the rubber coating layer, the static air permeability of the coated airbag fabric according to the present invention (as measured according to the ASTM D 737 method) is 2.0 cfm or less, preferably 0.3 to 1.7 cfm, more preferably 0.5 to 1.5 cfm, when ΔP is 125 pa; and 12 cfm or less, preferably 4 to 10 cfm, when ΔP is 500 pa. The dynamic air permeability of the coated fabric (as measured according to the ASTM D 6476 method) is 1,700 mm/s or less, preferably 200 to 1,600 mm/s, more preferably 400 to 1,400 mm/s.
[0044] In view of maintaining the packaging performance of the airbag fabric, it may not be desirable that the airbag fabric, either uncoated or coated, has the static air permeability or the dynamic air permeability above the upper limit of the corresponding air permeability range as defined above.
[0045] The airbag fabric may have a breaking elongation as measured at the room temperature according to the ASTM D 5034 method in the range of 25 to 60%, preferably about 30 to 50%. Preferably, the breaking elongation is 25% or greater in consideration of the toughness of the fabric, and 60% or less considering the edge comb resistance.
[0046] Further, the shrinkage of the fabric in the warp or weft direction as measured according to the ASTM D 1776 method is 1.0% or less, preferably 0.8% or less. Most preferably, the shrinkage in the warp or weft direction is not greater than 1.0% in consideration of the dimensional stability.
[0047] Preferably, the present invention is capable of maintaining such enhanced properties throughout an aging process carried out in different ways with a view to securing good performance as an airbag fabric. The aging process may include at least one selected from the group consisting of heat aging, cycle aging, and humidity aging. It is preferable for the airbag fabric to maintain high levels of strengths or other properties throughout all the three aging processes.
[0048] In this regard, the heat aging involves conducting a heat treatment on the fabric at high temperature, preferably in the range of 110 to 130° C. for 300 hours or more, or 300 to 500 hours. The cycle aging includes conducting heat aging, humidity aging and cold aging in cycles. Preferably, the cycle aging involves repeatedly conducting 2 to 5 cycles of a first aging at 30 to 45° C. and 93 to 97% in relative humidity (RH) for 12 to 48 hours, a second aging at 70 to 120° C. for 12 to 48 hours, and a third aging at −10 to −45° C. for 12 to 48 hours. The humidity aging includes conducting an aging under conditions of high temperature and high humidity, preferably at 60 to 90° C. and 93 to 97% RH for 300 hours or more, or 300 to 500 hours.
[0049] Particularly, the airbag fabric of the present invention has strength retention of at least 80%, preferably at least 85%, more preferably at least 90%, where the strength retention of the fabric is determined by calculating the percentage (%) of the strength after aging under the defined conditions with respect to the strength measured at the room temperature. Like this, the present invention can maintain high levels of strength and strength retention throughout a long-term aging under severe conditions of high temperature and high humidity, resulting in high performance as an airbag fabric.
[0050] In accordance with another embodiment of the present invention, there is provided a polyester fabric for airbag prepared from a polyester fiber having defined characteristics. The polyester fabric may comprise a polyester fiber having a filament fineness of 2.5 to 6.8 DPF, each fiber comprising at least 110 filaments.
[0051] Rather than using the conventional high-modulus polyester fiber with high strength and low elongation, the present invention uses a low-modulus polyester fiber having high strength and high elongation to provide a polyester fabric for airbag, which is superior in dimensional stability, air sealing performance, and folding property, as well as in energy absorption performance during inflation of the airbag.
[0052] The polyester fabric for airbag according to the present invention may comprise a polyester fiber having different values of fineness. The fineness of the polyester fiber may have an influence on the optimum range of the thermal resistance constant for securing good mechanical properties and high thermal resistance for the airbag fabric using the polyester fiber. Preferably, the polyester fabric may comprise a polyester fiber having a fineness of 400 to 650 denier. The polyester fiber may have a fineness of 400 to 650 denier in order to maintain low fineness and high strength in consideration of the folding property of the air cushion and the absorption performance for absorbing the high temperature high pressure energy generated during airbag unfolding. Preferably, the polyester fiber has a fineness of 400 denier or greater in consideration of the energy absorption performance; and 650 denier or less with a view to providing good folding property for the air cushion.
[0053] The polyester fabric may use a polyester fiber prepared from polyester chips having an intrinsic viscosity of 1.05 to 2.0 dl/g, preferably 1.10 to 1.90 dl/g. To maintain good properties throughout the aging process at the room temperature and under severe conditions of high temperature and high humidity, the polyester fiber is prepared from polyester chips having an intrinsic viscosity of 1.05 dl/g or above. For acquiring low shrinkage, the polyester fabric preferably comprises a polyester fiber prepared from polyester chips having an intrinsic viscosity of 2.0 dl/g or below.
[0054] Preferably, the polyester fiber has a shrinkage stress of 0.005 to 0.075 g/d at 150° C. which corresponds to the laminate coating temperature for general coated fabrics; and 0.005 to 0.075 g/d at 200° C. which corresponds to the sol coating temperature for general coated fabrics. In other words, the shrinkage stress of 0.005 g/d or greater at 150° C. or 200° C. prevents the fabric sagging under the heat during the coating process, and the shrinkage stress of 0.075 g/d or less reduces the relaxation stress in the process of cooling down to the room temperature subsequent to the coating process.
[0055] At least a predetermined level of tension is imposed on the polyester fiber during the heat treatment of the coating process to maintain the woven shape of the fiber, so the shrinkage at 177° C. is preferably 6.5% or below with a view to preventing deformation of the airbag fabric.
[0056] The shrinkage stress as defined herein is based on the measurement value under a fixed load of 0.10 g/d, and the shrinkage is based on the measurement value under a fixed load of 0.01 g/d.
[0057] The polyester fiber is preferably a polyethylene terephthalate (PET) fiber, more preferably a PET fiber comprising at least 70 mol. % of PET, most preferably a PET fiber comprising at least 90 mol. % of PET.
[0058] The higher filament count results in the softer the polyester fiber, but an extremely high filament count leads to low spinnability. Therefore, the filament count is preferably in the range of 96 to 160.
[0059] For the polyester fiber, Young's modulus at 1% elongation, that is, at position where the fiber has elongation of 1% is in the range of 60 to 100 g/de, preferably 75 to 95 g/de; and Young's modulus at 2% elongation, that is, at position where the fiber has elongation of 2% is in the range of 20 to 60 g/de, preferably 22 to 55 g/de, where the Young's modulus is measured according to the ASTM D 885 method. The present invention can prepare a novel airbag fabric using a polyester fiber having far lower initial Young's modulus, in comparison with the conventional polyester fiber of which the Young's modulus at 1% elongation is at least 110 g/de and the Young's modulus at 2% elongation is at least 80. g/de.
[0060] The Young's modulus of the polyester fiber is the modulus of elasticity defined as the slope in the elastic portion of the stress-strain curve obtained in the tensile testing and corresponds to the elastic modulus describing how much an object is elongated and deformed as the object is stretched at both ends. The fiber with high Young's modulus has good elasticity but results in deteriorated stiffness of the fabric; while the fiber with extremely low Young's modulus has good stiffness, but with low elastic recovery, deteriorating the toughness of the fabric. In this regard, the airbag fabric prepared from a polyester fiber having a relatively low initial Young's modulus overcomes the problems in association with high stiffness of the conventional polyester fabric and secures excellences in folding and packing properties and flexibility.
[0061] The polyester fiber has a tensile strength of 8.8 g/d or greater, preferably 8.8 to 10.0 g/d, more preferably 9.2 to 9.8 g/d; and a breaking elongation of 14 to 23%, preferably 15 to 22%. Further, the fiber has a dry shrinkage of 6.5% or less, or 1.0 to 6.5%, preferably 2.0 to 5.6%; and a melting heat capacity ΔH of 40 to 65 J/g, preferably 45 to 58 J/g.
[0062] As described above, the polyester fabric of the present invention is prepared using a polyester fiber having intrinsic viscosity, initial Young's modulus, and elongation in optimized ranges to impart good performance for the airbag fabric.
[0063] The polyester fiber can be prepared by melt-spinning a PET polymer into an undrawn fiber and then drawing the undrawn fiber. The specific conditions or procedures of the individual steps affect the properties of the polyester fiber directly or indirectly and thus contribute to the production of a polyester fiber suitable for use in the airbag fabric of the present invention.
[0064] In accordance with a more preferred embodiment of the present invention, the low-modulus polyester fiber with high strength and high elongation can be prepared by a method that comprises: melt-spinning a high-viscosity polymer comprising at least 70 mol % of polyethylene terephthalate and having an intrinsic viscosity of at least 1.05 dl/g at a low temperature of 200 to 300° C. to form a undrawn polyester fiber; and drawing the undrawn polyester fiber at a draw ratio of 5.0 to 6.0. In this method, a high-viscosity PET polymer having a low CEG (carboxyl end group) content, preferably 30 meq/kg or less, is subjected to melt spinning at low temperature, more preferably at low temperature and low spinning rate, where the melt-spinning process suppresses a decrease of intrinsic viscosity and an increase of CEG content to the maximum extent, maintaining good mechanical properties of the fiber and securing high elongation. Moreover, the subsequent drawing process which involves drawing at an optimized draw ratio of 5.0 to 6.0 can suppress a decrease of elongation to the maximum extent and thereby produce a low-modulus polyester fiber with high strength and high elongation, which can be effectively used in the manufacture of airbag fabrics.
[0065] In this regard, the higher temperature, for example, above 300° C. in the melt spinning process leads to thermal degradation of the PET polymer in great extent, intensifying a decrease of intrinsic viscosity and an increase of CEG content, increases molecular orientation to accelerate a decrease of elongation and an increase of Young's modulus, and causes damage to the surface of the fiber to deteriorate the whole properties of the fiber. An extremely high draw ratio, for example, greater than 6.0 in the drawing process results in excessive drawing, consequently with breaking or irregularity of the drawn fiber, so the resultant polyester fiber cannot have properties desirable for use in airbag fabrics. Further, a relatively low draw ratio in the drawing process leads to a low degree of orientation of the fiber and thus partially drops the strength of the resultant polyester fiber. Therefore, the draw ratio in the drawing process is preferably at least 5.0 to produce a low-modular polyester fiber with high strength and high elongation that are suitable for use in airbag fabrics.
[0066] The subsequent processes can be performed under the conditions optimized with a view to producing a low-modulus polyester fiber with high strength and high elongation at a high draw ratio. For example, in the direct spin draw process for preparing a polyester fiber with low Young's modulus as well as high strength and low shrinkage, the conditions for the process can be effectively optimized in a way that high-viscosity PET polymer chips are spun by melt spinning and subjected to drawing, thermo-setting, relaxation, and winding through multi-step godet rollers until the fiber is wound on a winder unit.
[0067] In this regard, the drawing process can be performed after the undrawn fiber passes through the godet rollers with an oil pick-up of 0.2 to 2.0%.
[0068] In the relaxation process, the relaxation is preferably in the range of 1 to 14%. The relaxation below 1% provides a polyester fiber that does not have shrinkage but a high degree of orientation likewise at a high draw ratio, resulting in failure to prepare a polyester fiber with high elongation and low Young's modulus. The relaxation above 14% causes severe vibration of the fiber on the godet rollers, deteriorating workability.
[0069] The drawing process may further include a thermo-setting process for processing the undrawn fiber by heat treatment at approximately 210 to 250° C. More preferably, the heat treatment can be conducted at a temperature of 230 to 250° C. with a view to an appropriate progress of the drawing process to enhance the melting heat capacity ΔH of the fiber for airbag. In this regard, the heat treatment temperature below 210° C. leads to a low degree of crystallization of the polymer and a decrease of relaxation due to insufficient thermal effect, consequently with poor shrinkage; while the heat treatment temperature above 250° C. results in a deterioration of strength and an increase of tar generated on the rollers due to thermal degradation, thus deteriorating workability.
[0070] The winding speed for the drawn fiber passing via the godet rollers is 2,000 to 4,000 m/min, preferably 2,500 to 3,700 m/min.
[0071] Such a process optimization allows production of a polyester fiber for airbag having low initial Young's modulus, high strength, and high elongation. Further, the optimization of the melt spinning process and the drawing process contributes to minimization of the CEG (Carboxyl End Group) content, where the CEG acts as an acid under high humidity to break the molecular chain of the polyester fiber. The resultant polyester fiber has low initial Young's modulus and high elongation and thus can be preferably used for airbag fabrics superior in mechanical properties, packing property, dimensional stability, impact resistance, and air sealing performance.
[0072] In accordance with still another embodiment of the present invention, there is provided a method for preparing an airbag fabric using a polyester fiber. The method for preparing a polyester fabric for airbag comprises: weaving a polyester fiber into a grey fabric for airbag; scouring the grey fabric for airbag; and tentering the scoured fabric.
[0073] In the present invention, the polyester fiber can be processed into the final airbag fabric by known methods of weaving, scouring, and tentering. The weaving type of the fabric is not specifically limited but preferably includes plain weaving or OPW type weaving.
[0074] Particularly, the airbag fabric of the present invention can be prepared from the polyester fiber as warp and weft threads by beaming, weaving, scouring, and tentering. The fabric can be woven with a known weaving machine, which is not specifically limited but includes a rapier loom, an air jet loom, or a water jet loom for plain woven fabrics, and a Jacquard loom for OPW fabrics.
[0075] In comparison with the prior art, the present invention involves a heat treatment process at higher temperature by using a polyester fiber with higher strength, higher elongation, and lower shrinkage. In other words, the woven grey fabric is scoured and tentered, and the tentered fabric is coated with a rubber component, dried and then solidified at a vulcanization temperature of 140 to 210° C., preferably 160 to 200° C., most preferably 175 to 195° C. The vulcanization temperature can be 140° C. or above in consideration of the mechanical properties of the fabric, such as tear strength, and 210° C. or below considering stiffness. Particularly, the heat treatment can be carried out on a multi-step basis in the order of, for example, a first heat treatment at 150 to 170° C., a second heat treatment at 170 to 190° C., and a third heat treatment at 190 to 210° C.
[0076] By preparing the polyester fabric of the present invention through a treat treatment at high temperature, the weave density can be enhanced due to the low-shrinkage characteristic of the polyester fiber, resulting in high dimensional stability and high air sealing performance, enhanced stiffness, and improved tear strength.
[0077] Further, the solidification process may be carried out at the above-defined vulcanization temperature for 30 to 120 seconds, preferably 35 to 100 seconds, most preferably 40 to 90 seconds. The solidification time less than 30 seconds results in a failure to solidify the rubber coating layer, thereby deteriorating the mechanical properties of the fabric and causing defoliation of the coating. The solidification time longer than 120 seconds leads to an increase in the stiffness and thickness of the final fabric product, consequently with deterioration of the folding property.
[0078] For the airbag fabric of the present invention, either one side or both sides of the woven fabric can be coated with the above-mentioned rubber component. The rubber coating layer can be applied by any known coating method, which includes, but is not specifically limited to, knife over-roll coating, doctor blade coating, or spray coating.
[0079] The coated airbag fabric can be processed into an airbag cushion in a defined shape through cutting and sewing processes. The airbag cushion is not specifically limited in shape and may be formed in any normal shape.
[0080] In accordance with a still another embodiment of the present invention, there are provided an airbag for vehicle comprising the polyester fabric, and an airbag system comprising the airbag, where the airbag system can be equipped with devices well-known to those skilled in the art.
[0081] The airbags are classified into frontal airbags and side curtain airbags. The frontal airbags include driver side airbags, passenger side airbags, lateral protection airbags, knee airbags, ankle airbags, pedestrian airbags, and so forth. The side curtain airbags deploy to protect occupants in the event of the vehicle's side impact collision or rollover. Accordingly, the airbag of the present invention includes both frontal airbags and side curtain airbags.
[0082] The present invention does not preclude addition or omission of the elements or components other than those stated herein under necessity, which are not specifically limited.
[0083] The present invention provides a polyester fabric having good mechanical properties, such as high strength and high thermal resistance, and an airbag for vehicle prepared using the polyester fabric.
[0084] The polyester fabric uses a polyester fiber having low Young's modulus, high strength, and high elongation to minimize thermal shrinkage throughout the heat treatment at high temperature, provide excellences in thermal resistance, mechanical properties, dimensional stability, and air sealing effect, and also secure good folding property and flexibility, thereby remarkably improving the packing property when the airbag is packed into a vehicle and also minimizing collision impacts on the occupants to protect the occupants with safety.
[0085] Accordingly, the polyester fabric of the present invention is preferably applicable to the manufacture of airbags for vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0086] FIG. 1 is an illustration of a general airbag system.
[0087] FIG. 2 shows photographs of a hot rod tester (an instrument for measuring thermal resistance constant) according to one embodiment of the present invention.
[0088] FIG. 3 is a graph plotting the amount of time taken for a hot rod to pass through the uncoated polyester fabric of Example 1 against the hot rod temperature.
[0089] FIG. 4 is a graph plotting the amount of time taken for a hot rod to pass through the uncoated polyester fabric of Comparative Example 1 against the hot rod temperature.
DETAILED DESCRIPTION OF THE INVENTION
[0090] Hereinafter, the present invention will be described in detail with reference to the preferred examples, which are given only to exemplify the present invention and not intended to limit the scope of the present invention.
EXAMPLES 1 TO 5
[0091] PET chips with a defined intrinsic viscosity were processed into a polyester fiber through a melt spinning machine in one step. The polyester fiber was woven into a grey fabric for airbag through a rapier loom and subjected to scouring and tentering to prepare an airbag fabric.
[0092] In the regard, Table 1 shows the intrinsic viscosity, CEG content, melt-spinning temperature, draw ratio, and heat treatment temperature of PET chips, the properties of the fiber, such as toughness, tear strength, tensile strength, and melting heat capacity (ΔH), and the warp and weft weave densities, weaving type, heat treatment temperature, rubber component, and coating weight of the fabric. The other conditions are as known in the prior art in association with the preparation of a polyester fabric for airbag.
[0000]
TABLE 1
Examples
Div.
1
2
3
4
5
PET content (mol %)
100
100
100
100
100
Intrinsic viscosity
1.25
1.33
1.40
1.55
1.75
(dl/g) of PET chip
CEG content (meq/kg)
30
27
24
23
22
of PET chip
Spinning temperature
293
295
295
295
295
(° C.)
Draw ratio
5.99
6.03
6.07
6.11
6.15
Heat treatment
235
239
243
240
244
temperature
(° C.) of fiber
Intrinsic viscosity
0.93
0.97
1.05
1.11
1.20
(dl/g) of fiber
Toughness (J/m 3 )
79
80
86
87
86
of fiber
Young's modulus (g/de)
85
84
79
78
82
at 1% elongation
Young's modulus (g/de)
47.0
46.6
26.8
26.3
26.0
at 2% elongation
Tensile strength
9.1
9.2
9.25
9.3
9.35
(g/de) of fiber
Breaking elongation
16.5
17
18.7
19.0
18.5
(%) of fiber
Melting heat capacity
47.6
48.6
49.5
51
52.5
(ΔH) of fiber
Dry shrinkage (%)
5.2
5.3
2.8
4.0
5.3
Filament fineness (DPF)
3.82
3.23
2.92
4.61
4.17
Total fineness (de)
420
420
420
600
600
Filament count
110
130
144
130
144
Weave density
49 × 49
49 × 49
49 × 49
43 × 43
43 × 43
(warp × weft)
Weaving type
Plain
Plain
Plain
Plain
Plain
weaving
weaving
weaving
weaving
weaving
Vulcanization
180
185
190
185
190
temperature (° C.)
Rubber component
Liquid
Liquid
Liquid
Liquid
Liquid
silicone
silicone
silicone
silicone
silicone
Rubber coating
25
25
25
25
25
weight (g/m 2 )
[0093] The polyester fabrics prepared in Examples 1 to 5 were measured in regard to properties according to the following methods. The measurement results are presented in Table 2.
[0094] (a) Thickness
[0095] The uncoated polyester fabrics before the coating process and the rubber-coated polyester fabrics were measured in regard to thickness according to the ASTM D 1777 procedure.
[0096] (b) Thermal Resistance Constant
[0097] The uncoated polyester fabric before the rubber-coating process and the rubber-coated polyester fabric were cut into test specimens in dimension of 50 mm×50 mm. Each of the specimens was placed in a hot rod tester illustrated in FIG. 2 . In the hot rod tester, the hot rod (steel, 10 mm diameter, 82 mm long, 50 g weight, thermal conductivity: 55 W/m·K) was heated up to 450 to 600° C. at a rate of 20° C./min and placed above the specimen at a distance “d” of about 76 mm. From above the specimen, the hot rod was dropped in free fall to measure the amount of time “t” (sec) taken for the hot rod to completely pass through the specimen from the point of contact with the specimen. Then the thermal resistance constant was determined as defined by the following calculation formula 1.
[0098] FIG. 3 is a retention time “t” (sec) taken for the hot rod to completely pass through the specimen from the point of contact with the specimen against the hot rod temperature for the uncoated polyester fabric of Example 1. In the same manner, the retention time of the hot rod during free fall was measured for each of the other polyester fabrics to calculate the thermal resistance constant according to the calculation formula 1.
[0099] This measurement procedure was repeatedly carried out 10 times for each polyester fabric to calculate the average thermal resistance constant, which is presented in Table 2.
[0000] Thermal resistance constant( X )=( T×t )/(600 ×D ) [Calculation Formula 1]
[0100] In the calculation formula 1, T is the temperature of a hot rod during free fall in the range of 350 to 750° C.; t is the amount of time (sec) taken for the hot rod to pass through the polyester fabric from a point of contact with the polyester fabric; and D is the thickness (mm) of the polyester fabric, where D for a coated fabric is the thickness of the fabric including a coating layer.
[0101] (c) Toughness
[0102] The toughness (J/m 3 ) of the fabric was determined according to the following calculation formula 2:
[0000] Toughness(work of rupture)=∫ 0 strain F·dl [Calculation Formula 2]
[0103] In the calculation formula 2, F denotes the load applied when the length of the polyester fiber or fabric is increased by dl; and dl is the increment of the length of the polyester fiber or fabric.
[0104] The toughness of the fabric was measured for the uncoated fabric before the coating process.
[0105] (d) Tear Strength
[0106] Test specimens in dimensions of 75 mm×200 mm were cut out of the uncoated fabric before the coating process and the coated fabric after the coating process. The upper and lower ends of each specimen were gripped between left and right spaces of the upper and lower jaw faces, respectively, in a testing machine according to the ASTM D 2261 TONGUE procedure. Based on the distance between the jaw faces, the jaw faces moved apart at a tearing rate of 300 mm/min with the gap between the jaw faces increasing at 76 mm/min to measure the tear strength of the airbag fabric.
[0107] (e) Tensile Strength and Breaking Elongation
[0108] The uncoated fabric before the coating process was cut into a test specimen, which was gripped in the lower stationary clamp of a tensile testing machine according to the ASTM D 5034 method, while the upper clamp was moved upward, to measure the tensile strength T 1 and the breaking elongation when the airbag fabric specimen was ruptured.
[0109] (f) Warp and Weft Shrinkages
[0110] The fabric was measured in regard to warp and weft shrinkages according to the ASTM D 1776 method. In the procedure, the uncoated fabric before the coating process was cut into a test specimen. Lines marking a 20 cm of length in the warp and weft directions were made in the specimen fabric before shrinkage. After one-hour heat treatment in a chamber at 149° C., the lengths of the mark lines of the shrunk specimen fabric were measured to determine the warp and weft shrinkages as follows:
[0000]
(
length
before
shrinkage
)
-
(
length
after
shrinkage
)
(
length
before
shrinkage
)
×
100
%
[0111] (g) Stiffness
[0112] The uncoated fabric before the coating process was evaluated in regard to stiffness according to the ASTM D 4032 procedure (circular bend test method) using a stiffness testing machine. The stiffness testing adopted the cantilever method, where the stiffing testing machine used a test stand declined at a predetermined angle for bending the fabric to measure the length of the fabric after bending.
[0113] (h) Air Permeability
[0114] According to the ASTM D 737 method, the uncoated fabric before the coating process was kept under conditions of 20° C. and 65% RH for one hour or longer. The static air permeability was determined as the volume of air passing through the circular cross-section 38 cm 2 in size, where the air pressure ΔP was 125 pa or 500 pa.
[0115] Further, the dynamic air permeability of the uncoated fabric was measured using a dynamic air permeability tester (TEXTEST FX 3350) according to the ASTM D 6476.
[0000]
TABLE 2
Examples
Div.
1
2
3
4
5
Toughness (kJ/m 3 ) of fabric
3.75
3.83
3.92
5.4
5.6
Tear strength (kgf)/uncoated fabric
19
19
20
26
26
Tear strength (kgf)/coated fabric
36
37
38
38
40
Tensile strength (kgf/inch) of fabric
227
230
234
297
305
Breaking elongation (%) of fabric
37
37
39
38
40
Stiffness (kgf)
0.40
0.40
0.35
1.00
0.90
Thickness (mm)/uncoated fabric
0.262
0.262
0.262
0.325
0.325
Thermal resistance constant/uncoated
1.30
1.30
1.32
2.67
2.69
(at 450° C., Hot Rod)
Thermal resistance constant/uncoated
1.11
1.11
1.12
1.51
1.53
(at 600° C., Hot Rod)
Thickness (mm)/coated fabric
0.268
0.268
0.268
0.332
0.332
Thermal resistance constant/coated
6.22
6.23
6.22
10.8
10.9
(at 450° C., Hot Rod)
Thermal resistance constant/coated
5.6
5.6
5.6
9.7
9.7
(at 600° C., Hot Rod)
Shrinkage (%)
Warp
0.5
0.5
0.4
0.4
0.5
Weft
0.3
0.3
0.4
0.3
0.3
Static air permeability
ΔP = 125 pa
1.0
0.9
0.8
0.6
0.6
(cfm)/uncoated
ΔP = 500 pa
9.5
9.3
9.2
5.4
5.4
Dynamic air permeability (mm/s)/
620
610
590
450
430
uncoated
COMPARATIVE EXAMPLES 1 TO 3
[0116] The procedures were performed in the same manner as described in Examples 1 to 5, excepting that polyester fabrics were prepared under the conditions given in the following table 3.
[0000]
TABLE 3
Comparative Examples
Div.
1
2
3
PET content (mol %)
100
100
100
Intrinsic viscosity
0.85
0.90
0.95
(dl/g) of PET chip
CEG content (meq/kg)
50
47
43
of PET chip
Spinning temperature
301
302
305
(° C.)
Draw ratio
4.95
5.03
5.10
Heat treatment
198
202
205
temperature
(° C.) of fiber
Intrinsic viscosity
0.61
0.63
0.65
(dl/g) of fiber
Toughness (J/m 3 )
59
63
67
of fiber
Young's modulus (g/de)
115
119
125
at 1% elongation
Young's modulus (g/de)
85
91
93
at 2% elongation
Tensile strength (g/de)
6.9
7.2
7.5
of fiber
Breaking elongation (%)
10
11
13
of fiber
Melting heat capacity
30.5
32.1
32.5
(ΔH) of fiber
Dry shrinkage (%)
15.5
15
13.7
Filament fineness (DPF)
6.18
6.18
6.18
Total fineness (de)
420
420
420
Filament count
68
68
68
Weave density
49 × 49
49 × 49
49 × 49
(warp × weft)
Weaving type
Plain
Plain
Plain
weaving
weaving
weaving
Vulcanization
180
185
190
temperature (° C.)
Rubber component
Liquid
Liquid
Liquid
silicone
silicone
silicone
Rubber coating
25
25
25
weight (g/m 2 )
[0117] The properties of the polyester fabrics prepared in Comparative Examples 1 to 3 are presented in the following table 4. In this regard, FIG. 4 shows a graph plotting the amount of time taken for a hot rod to pass through the uncoated polyester fabric of Comparative Example 1 against the hot rod temperature. The thermal resistance constant for each of the polyester fabrics of Comparative Examples 1 to 3 was calculated as described above.
[0000]
TABLE 4
Comparative Examples
Div.
1
2
3
Toughness (kJ/m 3 ) of fabric
2.4
2.5
2.7
Tear strength (kgf)/uncoated fabric
13
14
15
Tear strength (kgf)/coated fabric
21
23
23
Tensile strength (kgf/inch) of fabric
183
190
195
Breaking elongation (%) of fabric
18
20
20
Stiffness (kgf)
1.8
1.8
1.8
Thickness (mm)/uncoated fabric
0.265
0.265
0.265
Thermal resistance constant/uncoated
0.92
0.95
0.95
(at 450° C., Hot Rod)
Thermal resistance constant/uncoated
0.82
0.84
0.84
(at 600° C., Hot Rod)
Thickness (mm)/coated fabric
0.271
0.271
0.271
Thermal resistance constant/coated
4.83
4.84
4.85
(at 450° C., Hot Rod)
Thermal resistance constant/coated
4.35
4.35
4.35
(at 600° C., Hot Rod)
Shrinkage (%)
Warp
1.3
1.3
1.2
Weft
1.2
1.0
0.9
Static air
ΔP = 125 pa
2.5
2.4
2.4
permeability
ΔP = 500 pa
13.8
13.7
13.6
(cfm)/uncoated
Dynamic air permeability
1,950
1,920
1,910
(mm/s)/uncoated
[0118] As shown in Tables 2 and 4, relative to the airbag fabrics of Comparative Examples 1 to 3 using the conventional polyester fiber, the polyester fabrics of Examples 1 to 5 using a low-modulus polyester fiber with high strength and high elongation to have a specific range of thermal resistance constant can exhibit good mechanical properties and enhanced properties, such as shrinkage, stiffness, and air permeability.
[0119] More specifically, the polyester fabrics of Examples 1 to 5 have a thermal resistance constant of 1.3 to 2.69 for an uncoated fabric when the actual temperature of the hot rod is 450° C.; and a thermal resistance constant of 1.11 to 1.53 for an uncoated fabric when the actual temperature of the hot rod is 600° C., thereby acquiring very good properties, such as shrinkage of 0.3 to 0.5%, toughness of 3.75 to 5.6 kJ/m 3 , tear strength of 19 to 26 kgf for an uncoated fabric, tensile strength of 227 to 305 kgf/inch, and stiffness of 0.35 to 1.0 kgf. It is therefore concluded that the polyester fabric of the present invention using a high-strength, low-elongation polyester fiber with low Young's modulus to acquire a specific range of thermal resistance constant can have properties in optimum ranges for an airbag fabric and thus secure good folding and packing properties as well as high dimensional stability and good mechanical properties.
[0120] Contrarily, the airbag fabrics of Comparative Examples 1 to 3 using the conventional high-modulus polyester fiber with low strength, low elongation, and high filament fineness have a thermal resistance constant of 0.92 to 1.16 for an uncoated fabric when the actual temperature of the hot rod is 450° C.; and a thermal resistance constant of 0.82 to 0.93 for an uncoated fabric when the actual temperature of the hot rod is 600° C., resulting in drastic deterioration in mechanical properties, such as shrinkage (0.9 to 1.3%), tensile strength (187 to 200 kgf/inch), and tear strength for an uncoated fabric (13 to 20 kgf). The airbag fabrics of Comparative Examples inferior in mechanical properties and dimensional stability to the airbag fabrics of Examples 1 to 5 are therefore considered unsuitable for use as airbag fabrics.
|
The present invention relates to an airbag fabric comprising a polyester fiber, and more particularly to a polyester fabric having a thermal resistance constant (X) of 1.0 to 6.5 in the uncoated fabric state, a preparation method for the same, and an airbag for vehicle comprising the same.
The airbag fabric of the present invention uses a polyester fiber having low Young's modulus, high strength and high elongation to impart good mechanical properties, such as high strength and high thermal resistance, and good folding property, high dimensional stability, and good air sealing effect as well, thereby minimizing collision impacts on occupants to protect the occupants with safety.
| 3
|
This is a continuation-in-part patent application claiming priority to U.S. patent application Ser. No. 12/243,036, filed Oct. 1, 2008.
BACKGROUND OF THE INVENTION
1. Field of the Invention
Applicant's invention relates to a gutter retaining system for affixing a gutter to a building without placing holes in the gutter. More specifically, the present invention relates to an interlocking system that incorporates a gutter clip and a gutter hanger to affix the gutter to a retaining clip attached to a fascia board of a building, thereby eliminating the need to place holes in the gutter itself to insert screws or nails. The gutter hanger of the gutter retaining system is constructed of a single piece and incorporates an upper portion designed to support a leaf protection device. Alternatively, the upper portion is removably attached to the gutter hanger.
2. Description of the Related Art
For years property owners have struggled with the destructive effects of water on their buildings. However, by channeling the water away from the structure, building owners can reduce the damage caused by water. This can be accomplished through the use of a gutter system to channel water off the roof and away from the foundation. However, any damaged lengths of gutter or drain pipe caused by wear, improper installation, or sagging can cause leaks which can result in water damage to the building.
Traditionally, gutters have been attached by nailing the gutter directly to the building. Building contractors typically used a spike and ferrule system, in which a narrow, tubular spacer, the ferrule, is placed between the front wall of a gutter and its rear wall, ensuring that the front wall remains at a uniform distance from the rear wall. A spike or long nail is then punched through the outside of the front wall of the gutter, through the ferrule, through the back wall of the gutter, and into the wall or fascia board of the building.
A gutter installed in this way ends up with its front wall tilted forward towards the ground. Once this occurs the captured rainwater and other debris tends to pool along the outer edge of the gutter causing the weight on the outer edge of the gutter to increase, thus resulting in the gutter pulling away from the wall or fascia board. Further, while this manner of installation temporarily secures the gutter in place, it does not ensure that water will not run behind the gutter. If water is allowed to run and collect behind the gutter, eventually the integrity of the wood or fascia board begins to weaken and the gutter is slowly pulled away from the building.
The utilization of gutter hangers is the most common way in which installers have tried to improve the integrity and life of gutter systems. A gutter hanger is basically a modified spacer that is shaped like a flat plate, with both ends mined upward. A first end of the gutter hanger is inserted under the lip of the front wall of the gutter, typically located along the inner surface of the front wall of the gutter, along the top thereof. The second end, with a pre-punched nail hole, is placed against the rear wall of the gutter. A nail or screw is then inserted through the nail hole, through the rear wall of the gutter, and into the building wall or fascia board. A variation of this method includes placing the second end of the gutter hanger over the top of the rear wall of the gutter. The gutter hanger is then nailed directly into the building wall or fascia board. While these methods of installation eliminate the need for inserting the nail or screw through the front wall of the gutter, a hole is still placed through the back wall of the gutter.
Another problem associated with gutter systems is the collection of leaves, dirt and other debris in addition to water. Collection of such extraneous matter adds substantial weight to the gutter, often resulting in bending or deforming the gutter, or the gutter tearing away from the building or fascia board. As a way to prevent leaves, dirt and other debris from entering the gutter, many different leaf protection devices have emerged. Leaf protection devices are typically installed over the gutter in a manner as to substantially cover the gutter while leaving small areas of the gutter exposed so that water may collect therein. Yet, installation of such leaf protection devices—especially on preexisting gutters—is often cumbersome and time consuming.
The reason that installation of leaf protection devices is cumbersome and time consuming is that in order to install most leaf protection devices, brackets must also be installed to support those devices. Typically, the brackets need to be installed onto the gutter hangers. Yet, only certain brackets are appropriate to be installed on certain hangers. Therefore, often times not only do brackets need to be installed, but gutter hangers must be replaced as well. As a result, the nails or screws must be removed from the gutter hangers. Thus, the entire gutter system must be taken down, the gutter hangers must be changed out, the brackets must be installed, and then the gutter system must be reinstalled on the same building. Only then is it possible to install the leaf protection device.
It is therefore desirable to provide a gutter system that affixes a gutter to a building without placing holes in the gutter. It is also desirable to provide a system for affixing a gutter which reinforces the integrity of the gutter to prevent the gutter from sagging or tearing away from the building. It is also desirable to provide a gutter hanger which is constructed to incorporate support brackets to support a leaf protection device. Alternatively, it is desirable to provide a gutter hanger that is designed to allow the optional addition of support brackets at a later time with ease, and without needing to replace the gutter hanger.
BRIEF SUMMARY OF THE INVENTION
The gutter system of the present invention provides the advantage of affixing a gutter to a building or fascia board of a building without placing holes in the gutter. The gutter system of the present invention also provides the advantages of providing reinforcement of the structural integrity of the gutter while providing support brackets to support a leaf protection device. The gutter system of the present invention incorporates a gutter clip and a gutter hanger to affix the gutter to a retaining member. The retaining member has a flat vertical portion which rests flush against a fascia board of a building in the preferred embodiment. The retaining member is attached to the fascia board by a nail or screw, and is the only site of attachment of the present system to the fascia board itself. The retaining member extends vertically along the vertical portion above the screw or nail. An arm portion of the retaining member extends downwardly and outwardly from a top portion of the retaining member, and terminates in a hook portion which angles inward and upward toward the vertical portion. Thus, a hook is formed by the retaining member to hold the gutter hanger therein.
A gutter clip is designed to attach directly to the gutter. The gutter clip has a vertical portion which is disposed against the outer surface of the rear wall of the gutter, between the gutter and the fascia board. Along the lower end of the vertical portion of the gutter clip, a horizontal spacer extends outward toward the fascia board, and terminates in a vertical protrusion which extends upward and is substantially parallel to the vertical portion. This spacer portion of the gutter clip facilitates keeping the gutter substantially level where there are substantial spaces or overlay between the fascia board and the overhang of shingles, or where the fascia board is tilted inward, toward the building or structure. A hanging portion of the gutter clip is located along the top portion of the gutter clip. The hanging portion curves downward on the side of the vertical portion opposite the spacer portion, creating a cavity for receiving a top edge of the rear wall of the gutter. The hanging portion curves slightly past parallel with the vertical portion, such that it is angled slightly toward the vertical portion. Thereafter, the hanging portion terminates in an end portion which angles slightly downward and away from the vertical portion of the gutter clip.
A gutter hanger of the preferred embodiment has a hanger portion which has a first end. The first end has a vertical wall extending substantially vertically and an inward wall which projects inward, toward a vertical portion of the gutter hanger, and slightly upward. The second end is opposite the first end, and has a vertical wall extending upward from the hanger portion, and a hanging portion which curves outward toward the fascia board and then downward along the vertical portion of the retaining member, as described herein below. The intermediate section of the gutter hanger is disposed between the first and second ends and generally spans the width of the gutter, thereby maintaining the shape and structural integrity of the gutter.
A vertical portion of the gutter hanger extends vertically from the intermediate section and terminates in a top portion of the gutter hanger. The vertical portion and the top portion form the bracket support to support a leaf protection device. The top portion has a front section which generally conforms to the shape of a front portion of the leaf protection device. The rear section of the top portion extends toward the roof of the building, terminating above the intermediate section of the hanger portion. At the end of the rear section, there is a knob or boss for receiving a support strap. The knob has a small locking protrusion along its rearward portion to prevent the support strap from rotating when engaged with the knob.
The gutter clip slides over the top edge of the back wall of a gutter such that the vertical portion of the gutter clip is substantially flush with the outer surface of the back wall of the gutter, with the horizontal spacer aligning outward. The top of the back wall of the gutter slides into the hanging portion, such that part of the hanging portion and the end portion are on the inner surface of the back wall of the gutter.
The gutter hanger is then inserted into the gutter. The inward wall of the first end of the gutter hanger engages the lip on the inner surface of the front wall of the gutter, and the vertical wall of the first end of the gutter hanger abuts against a portion of the front wall of the gutter. The second end of the gutter hanger is placed over the gutter clip such that the vertical wall of the second end of the gutter hanger contacts the hanging portion and the end portion of the gutter clip on the inside of the rear or back wall of the gutter. The hanging portion of the gutter hanger then wraps around the hanging portion of the gutter clip. The intermediate section of the gutter hanger is disposed within the gutter and lies across the width of the gutter.
The gutter, gutter clip, and gutter hanger are installed on the building by placing the gutter hanger between the vertical portion and the hook portion of the retaining member. After securing the gutter, a leaf protection device may be installed over the top portion of the gutter hanger. Screws or nails can be placed through the leaf protection device and into the top portion of the gutter hanger to secure the leaf protection device to the hanger.
Optionally, prior to installing the leaf protection device, a support strap may be removably attached to the top portion. The support strap has a clip for receiving the knob on the rear section of the top portion of the gutter clip. The clip slides onto the knob, and the strap extends toward the roof, where it can rest on the roof. As installed, the support strap relieves part of the stress placed on the top portion and the vertical portion of the gutter clip by the leaf protection device. The locking protrusion prevents rotation of the strap with respect to the knob, so that the strap can rest on the roof in a fixed position and support the vertical portion without penetrating the roof with nails or screws to attach the support strap to the roof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the gutter system of the present invention with a leaf protection device;
FIG. 2 is a side view of the gutter system of the present invention showing the leaf protection device resting on the gutter hanger;
FIG. 3 is a perspective view of the gutter hanger of the present invention;
FIG. 4 is a perspective view of an alternative embodiment of the gutter hanger of the present invention;
FIG. 5 is a side view of an alternative embodiment of the gutter hanger of the present invention;
FIG. 6 is a perspective view of the gutter system of the present invention with the alternative embodiment of the gutter hanger;
FIG. 7 is a side view of the gutter system of the present invention showing the leaf protection device resting on the alternative embodiment of the gutter hanger;
FIG. 8 is a perspective view of the retaining member of the present invention;
FIG. 9 is a perspective view of the gutter clip of the present invention;
FIG. 10 is a perspective view of the support strap of the present invention.
FIG. 11 is a side view of an alternative embodiment of the gutter hanger of the present invention; and
FIG. 12 is a side view of the gutter system of the present invention with an alternative embodiment of the gutter hanger.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1 , 2 and 3 , the gutter system 10 of the present invention is disclosed. The gutter system 10 comprises a gutter hanger 12 , a gutter clip 14 and a retaining member 16 . As shown in FIGS. 2 and 8 , the retaining member has a vertical portion 16 a which lies flush against a fascia board 18 , and is secured thereto by a screw 20 . In the present gutter system 10 , the screw 20 being place through the retaining member 16 and into the fascia board 18 is the only point of attachment between the gutter 22 and the building or structure (not shown). However, a nail or other appropriate attaching device could be used in place of the screw 20 . The retaining member 16 has an arm 16 b on the upper end of vertical portion 16 a which extends downward and outward from the upper end of the vertical portion 16 a . A hook portion 16 c is contiguous with arm 16 b , and angles inward and upward toward vertical portion 16 a . As discussed in detail below, the gutter clip 14 and gutter hanger 12 are secured to the retaining member 16 between the hook portion 16 c and the vertical portion 16 a.
Furthermore, although the retaining member 16 is shown and described as having a vertical member that is flush against the fascia board 18 , various modifications of the retaining member 16 could be made. For instance, the modifications disclosed in U.S. patent application Ser. No. 10/939,246, wherein a horizontal spacer extends from a lower part of vertical portion 16 a opposite arm 16 b and hook portion 16 c to accommodate different slanting angles of the fascia board 18 .
Referring to FIGS. 2 and 9 , the gutter clip 14 of the gutter system 10 is shown. The gutter clip 14 has a vertical portion 14 a . At a lower end of vertical portion 14 a , a horizontal spacer 14 b extends outward, and a vertical protrusion 14 c extends upward, substantially parallel to vertical portion 14 a from the end of the spacer 14 b . The spacer 14 b aides in keeping the gutter substantially level when the gutter hanger 12 is attached to the retaining member 16 . Thus, spacer 14 b separates the rear wall 22 a of the gutter 22 from the fascia board 18 . A hanging portion 14 d of the gutter clip 14 is located along the top of the gutter clip 14 . The hanging portion 14 d curves downward on the side of vertical portion 14 a opposite spacer 14 b , creating a cavity for receiving a top portion of the rear wall 22 a of gutter 22 . Hanging portion 14 d curves past parallel with vertical portion 14 a to angle slightly toward vertical portion 14 a . Thereafter, hanging portion 14 d terminates in an end portion 14 e which angles downward and outward from said vertical portion 14 a.
Hanging portion 14 d of gutter clip 14 slides over the top edge of rear wall 22 a of gutter 22 . As engaged with rear wall 22 a , vertical portion 14 a of gutter clip 14 is substantially flush with the outer surface of rear wall 22 a , and spacer 14 b is aligned outward from rear wall 22 a . The top of rear wall 22 a slides into the cavity between vertical portion 14 a and hanging portion 14 d such that part of hanging portion 14 d and end portion 14 e are disposed along the inner surface of rear wall 22 a . Hanging portion 14 d and end portion 14 e are then crimped toward vertical portion 14 a using a pair of pliers or other suitable crimping device, thus securing gutter 22 to gutter clip 14 .
Referring to FIGS. 1 , 2 and 3 , the preferred embodiment of gutter hanger 12 is disclosed. In the preferred embodiment, gutter hanger 12 is constructed of a single piece, having a hanger portion 26 , a vertical portion 28 and a top portion 30 . Hanger portion 26 reinforces and helps maintain the structural shape and integrity of gutter 22 , whereas vertical portion 28 and top portion 30 serve as a support bracket for a leaf protection device 24 . Hanger portion 26 has a first end 32 which engages a portion of front wall 22 b of gutter 22 . First end 32 has a vertical wall 32 a and an inward wall 32 b . Inward wall 32 b is angled inward, toward vertical portion 28 , and slightly upward. As shown in FIGS. 1 and 2 , inward wall 32 b engages a lip 22 c of front wall 22 b , and is disposed between said lip 22 c and the inner surface of front wall 22 b . Likewise, vertical wall 32 a is disposed along the inner surface of front wall 22 b , along a portion thereof.
Referring to FIG. 3 , hanger portion 26 of gutter hanger 12 has a second end 34 disposed on the opposite end of hanger portion 26 from first end 32 . Second end 34 has a vertical wall 34 a extending upward and a hanging portion 34 b . Hanging portion 34 b extends downward from vertical wall 34 a , and extends parallel to vertical wall 34 a for a slight distance, forming a cavity for receiving the hanging portion 14 d and end portion 14 e of gutter clip 14 , which is attached to rear wall 22 a of gutter 22 . An intermediate section 36 of hanger portion 26 is disposed between first end 32 and second end 34 , forming a contiguous hanger portion 26 . Intermediate section 36 is disposed across and inside gutter 22 . Referring to FIGS. 1 and 2 , once second end 34 receives hanging portion 14 d and end portion 14 e of gutter clip 14 , second end 34 of gutter hanger 12 may be crimped using pliers or other suitable crimping devices to secure gutter hanger 12 to gutter clip 14 , and thus, gutter 22 . Once secured, second end 34 is inserted into a cavity between hook portion 16 c and vertical portion 16 a of retaining member 16 . Second end 34 fits tightly within the cavity between hook portion 16 c and vertical portion 16 a to allow retaining member 16 to securely hold gutter 22 , gutter hanger 12 and gutter clip 14 .
Returning to FIG. 3 , vertical portion 28 extends generally upward from intermediate section 36 , and terminates at top portion 30 . As shown, vertical portion 28 has a lower section 28 a that extends generally upward and outward toward a front section 30 b of top portion 30 . An upper section 28 b of vertical portion 28 is adjacent lower section 28 a and extends vertically from lower section 28 a . Upper section 28 b is substantially perpendicular to a rear section 30 a of top portion 30 and intermediate section 36 . A platform 36 a is contiguous with and elevated above intermediate section 36 . On one end of the platform 36 a , a small vertical wall 36 b extends vertically slightly above platform 36 a . On the opposite end, platform 36 a adjoins lower section 28 a of vertical portion 28 . Platform 36 a is disposed between first end 32 of hanger portion 26 and vertical portion 28 .
Front section 30 b of top portion 30 extends outward from rear section 30 a , and angles downward toward first end 32 . An end section 30 c terminates front section 30 b and angles downward and slightly inward from first end 32 . As shown in FIG. 2 , end section 30 c is disposed above first end 32 , rearward of vertical wall 32 a . Rear section 30 a is substantially horizontal and extends rearward from vertical portion 28 . Rear section 30 a terminates in a knob 38 . Top portion 30 as shown accommodates and supports a “nose forward” leaf protection device, as is commonly known in the art. However, top portion 30 could be designed to accommodate other types of leaf protection devices.
Referring to FIGS. 1 , 2 and 3 , once second end 34 is secured within retaining member 16 between hook portion 16 c and vertical portion 16 a , the leaf protection device 24 may be installed. Prior to installing leaf protection device 24 , a support strap 40 is removably attached to top portion 30 . Referring to FIG. 10 , support strap 40 has a clip 40 a on one end thereof which receives knob 38 of rear section 30 a . Clip 40 a slides onto knob 38 . The locking protrusion at the rear portion of knob 38 is engaged to a second recess within clip 40 a to prevent vertical rotation of the support strap 40 with regard to knob 38 . However, the support strap 40 can slide laterally with respect to knob 38 . Support strap 40 extends rearward and contacts a roof (not shown) of the building. Support strap 40 aids in relieving stress placed on top portion 30 and vertical portion 28 by leaf protection device 24 . It should be understood that support strap 40 could be eliminated from the system 10 , in which case leaf protection device 24 could be placed directly on top portion 30 without having support strap 40 anchoring top portion 30 to the roof.
Referring to FIG. 2 , leaf protection device 24 is placed over top portion 30 . Nose portion 24 a of leaf protection device 24 substantially conforms to the shape of front section 30 b of top portion 30 . Nose portion 24 a extends over end portion 30 c of front portion 30 b and extends downward and inward toward platform 36 a of intermediate section 36 . There is a gap G between lip 22 c of gutter 22 and leaf protection device 24 , thus allowing the entry of water into gutter 22 while substantially preventing leaves and other debris from entering gutter 22 . A base 24 b of leaf protection device 24 rests on platform 36 a and is prevented from sliding laterally off of platform 36 a by vertical portion 28 and vertical wall 36 b . By providing platform 36 a to receive base 24 b , the weight of nose portion 24 a on front section 30 b is reduced, thus reducing the stress load on front section 30 b . Body portion 24 c of leaf protection device 24 extends toward the roof of the building, covering rear section 30 a , knob 38 , and support strap 40 . A screw 20 is placed through body 24 c and into the roof of the building to secure leaf protection device 24 to the building. Likewise, a screw 20 may optionally be placed through body portion 24 c and rear section 30 a of top portion 30 to further secure leaf protection device to gutter hanger 12 .
Referring now to FIGS. 4 through 7 , an alternative embodiment of the present invention is disclosed. Referring to FIGS. 4 and 5 , in the alternative embodiment, gutter hanger 12 is constructed such that vertical portion 28 is separate, but slidably attachable to hanger portion 26 . Vertical portion 28 has lower section 28 a and upper section 28 b which terminates at top portion 30 . Thus, vertical portion 28 and top portion 30 are constructed of a single piece. Lower section 28 a terminates at platform 36 a . However, platform 36 a is not contiguous with intermediate section 36 of hanger portion 26 . Instead, there is a receiving surface 36 c on which platform 36 a rests when vertical portion 28 is slidably attached to hanger portion 26 . Receiving surface 36 c is elevated above, but contiguous with intermediate section 36 . Legs 36 e are disposed underneath receiving surface 36 c and are contiguous with intermediate section 36 and receiving surface 36 c . By being disposed underneath receiving surface 36 c , legs 36 e define grooves for slidably receiving platform 36 a . Legs 36 d extend vertically downward from platform 36 a . Legs 36 d extend downward from platform 36 a and turn inward toward one another below platform 36 a , forming a receiving cavity substantially the same size and shape as intermediate section 36 formed by legs 36 e and receiving surface 36 c of hanger portion 26 . This construction allows vertical portion 28 to be slidably attached to hanger portion 26 , as shown in FIGS. 4 and 5 .
The advantage of having an a two-piece gutter hanger 12 as described hereinabove, is shown in FIGS. 6 and 7 . The hanger portion 26 can readily be installed in the gutter system 10 , as described herein. However, if it is not desired to install a leaf protection device 24 , there is no need to install vertical portion 28 and top portion 30 . An advantage of this embodiment is that if it is later desired to add a leaf protection device 24 to the gutter system 10 wherein hanger portion 26 is already installed, vertical portion 28 can slide onto hanger portion 26 , allowing leaf protection device 24 to be installed on top of the gutter system 10 as described herein, without the need to remove the gutter 22 , gutter clip 14 and hanging portion 26 from the retaining member 16 to replace hanging portion 26 with a one piece gutter hanger 12 . Moreover, the attachment of the vertical portion 28 to the hanger portion 26 by the groove formed underneath platform 36 a corresponding to the shaped formed by legs 36 e and receiving surface 36 c allows the vertical portion 28 to slide laterally with respect to hanger portion 26 . The ability to slide laterally provides an advantage in that it prevents buckling of the gutter 22 and/or leaf protection device 24 as movement of the component parts of the system 10 occurs, especially during summer months as the temperature rises. Moreover, although described as being a part of the system 10 of the present invention, it should be understood that hanger portion 26 and vertical portion 28 can be installed on pre-existing gutters that are not part of the system 10 .
Referring to FIGS. 11 and 12 , another embodiment of the present invention is disclosed. Gutter hanger 12 is constructed such that vertical portion 28 is separate, but slidably attachable to hanger portion 26 in the same manner as disclosed hereinabove in reference to the embodiment of gutter hanger 12 shown in FIGS. 4 through 7 . However, in the embodiment shown in FIGS. 11 and 12 , a backstop 36 f extends vertically from platform 36 a , and curves slightly forward toward vertical wall 36 b . As shown in FIG. 12 , base 24 b of leaf protection device 24 is inserted between backstop 36 f and vertical wall 36 b and rests there between. The slight forward curvature of backstop 36 f prevents base 24 b from sliding out of the space between backstop 36 f and vertical wall 36 b . This embodiment accommodates shorter bases 24 b , as exist on some leaf protection devices. It should be understood that backstop 36 f can be eliminated altogether, or placed anywhere along platform 36 to accommodate the varying bases of different leaf protection devices.
Backstop 36 f is shown as being disposed approximately half way between lower section 28 a of vertical portion 28 and vertical wall 36 b . However, backstop 36 f could be placed at any position along platform 36 a between lower section 28 a and vertical wall 36 b so long as the distance between backstop 36 f and vertical wall 36 b is sufficient to receive base 24 b of leaf protection device 24 . Furthermore, although gutter hanger 12 is shown the embodiment disclosed in FIGS. 11 and 12 as having vertical portion 28 separate but attachable to hanger portion 26 , gutter hanger 12 having backstop 36 f could be comprised of a single piece, as disclosed in FIGS. 1 through 3 .
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention will become apparent to persons skilled in the art upon the reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention.
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An interlocking gutter system that incorporates a gutter clip and a gutter hanger to affix a gutter to a retaining clip attached to a fascia board of a building, thereby eliminating the need to place holes in the gutter itself to insert screws or nails. The gutter hanger of the present invention is constructed of a single piece which has a hanger portion which is disposed substantially within the gutter and spans the width of the gutter to maintain the shape and structural integrity of the gutter. A vertical portion of the gutter hanger extends vertically from the hanger portion and terminates in a top portion which provides support to a leaf protection device. Alternatively, the gutter hanger is constructed of a hanger portion, and a separate vertical portion which is contiguous with the top portion, and is also slidably attachable to the hanger portion.
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BACKGROUND OF THE INVENTION
1. Field of Invention
The invention pertains to looms wherein fabric as it is formed is incrementally advanced by a take-up roll that is rotated by the combination of a ratchet wheel operatively associated with one end thereof and so-called feed and hold-back pawls which are mounted so as to engage the teeth of said ratchet wheel.
2. Description of the Prior Art
In looms for weaving it is customary to provide a knockoff means which serves to initiate stopping of the looms preferably by disconnecting the source of power and applying a brake to accelerate the stopping function. Such mechanism is normally dependent upon or functions in accordance with indications taken from a weft feeling or sensing mechanism, such as in and of itself, well known to those conversant in the weaving art.
When a loom stops as a result of weft breakage, the loom is turned over to that shed opening containing the broken weft, and during this turning over of the loom, the reed is caused to strike the fell line of the fabric. The reed's striking of the fell during this turning over of the loom has a tendency to pack the preceeding length of weft more tightly than those which form the fabric immediately adjacent thereto or which precede said length of weft. This additional beat-up or packing of the weft also has a tendency to stretch slightly the warp threads at this point and together form a distinct line or, in other words, a starting mark when the loom is started in order to resume weaving.
A number of prior art patents disclose devices for preventing start marks in fabric and for a more detailed description of these devices, attention is directed to U.S. Pat. Nos. 3,165,125 and 3,891,010.
When a loom stops as a result of a weft break, the start mark preventer of the present invention is adapted to be pre-set so that the fell can be moved forwardly of the reed beat-up position a pre-selected distance to meet the requirements of a particular type of fabric when the loom is turned over to the shed opening containing the broken pick. After removal of the broken pick of weft, the device is again actuated and the fell is caused to return to the precise position whereat weaving can be resumed without creating a start mark in the fabric.
SUMMARY OF THE INVENTION
The improved start mark preventer according to the present invention defines a manually operable control device having a control handle for a control pawl that is disposed in operative engagement with the loom's ratchet wheel which, as is well known, is effective by means of conventional feed and hold-back pawls of advancing the fabric as it is formed. The control handle is selectively movable within the limits of a guide bracket that is provided with selectively positionable pin members that define a neutral, first and second position for said control handle. The pin members are selectively positionable which permits the control handle to be moved to those positions which are best suited for the particular fabric being woven.
The control handle is in the neutral position during loom operation and when stopped by a weft break, it is manually pushed to its first position which is effective in rotating the take-up roll in a direction to move the fell forwardly of the reed's beat-up position. When the handle is moved to its second position, the fell is permitted to return to the position proper for the next pick and upon starting the loom, said handle will automatically move to its neutral position.
It is a general object of the invention to provide a means for preventing starting marks in fabric upon starting up a loom after a weft break.
It is a further object of the invention to move the fabric and its fell line forwardly of the reed's beat-up position when turning a loom over the shed opening containing the broken pick of weft.
A more specific object of the invention is to provide a mechanism which is effective in moving the fabric and its fell line forwardly of the reed's beat-up position and for returning the same to a position proper for the insertion of the next pick without disturbing the take-up or let-off settings of the loom.
These and other objects of the invention will become more fully apparent by reference to the appended claims and as the following detailed description proceeds in reference to the figures of drawing wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a portion of a loom showing the device according to the invention applied thereto;
FIG. 2 is a view in side elevation of the device shown in FIG. 1 showing the invention's control handle in its first and second positions;
FIG. 3 is a view in side elevation of a loom's reed, lay beam and temple showing by means of phantom lines the fell of the fabric in its normal position and by solid lines the position to which it is moved forwardly of the reed's beat-up position;
FIG. 4 is a view in front elevation showing additional detail of the device in FIGS. 1 and 2; and
FIG. 5 is a view similar to FIG. 2 but showing the control handle in its neutral or loom operating position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Now referring to the figures of drawing, enough of a loom is shown in FIG. 1 to serve as a basis for a detailed description of the invention applied thereto.
In FIG. 1 the forward left hand side of a shuttleless loom is shown and among the various parts thereof there is shown a portion of the left hand loomside at 10 and breast beam at 12. The loom's fabric take-up roll is identified by numeral 14 and is rotated in a well known manner by gearing contained within a housing 16 that is operatively connected to the loom's take-up ratchet wheel 18 by means of a shaft 20. This shaft 20 is horizontally disposed and extends from the housing 16 outwardly through an opening (not shown) in the loomside 10 and has the ratchet wheel 19 fixed thereon in slightly spaced relation to said loomside. Intermediate the ratchet wheel 18 and the loomside 10 the shaft 20 has a double armed lever 22 (FIG. 1) pivotably mounted thereon. A first arm 24 of the double armed lever 12 extends in a generally upwardly direction and has a feed pawl 26 pivotably mounted on the end thereof so as to operatively engage the teeth of the ratchet wheel 18. The second arm of this double armed lever 22 is identified by numeral 28 and extends in a generally downward direction and is attached at 30 to a link 32 which is connected to a well known source of drive for effecting periodic actuation of the feed pawl 26 and rotation of the ratchet wheel 18. A conventional form of hold back pawl 34 functions in a known manner to maintain the ratchet wheel in each position to which it is advanced by the feed pawl 26. As shown in FIGS. 1 and 5, this hold back pawl 34 is pivotably mounted on the loomside 10 so as to engage the teeth of the ratchet wheel 19 forwardly of the position of the feed pawl 26 and includes an integrally formed ear 35 which extends in the direction of the loom's shipper handle 36.
Referring again to FIGS. 1 and 5, the loom is provided with a conventional foot actuated feed pawl release mechanism which includes a lever generally indicated by numeral 38 pivotably attached to the loomside 10 as at 40. The lower end of this lever defines a foot pedal 42 and one end of an upwardly extending actuating rod 44 is pivotably attached to said lever as at 46. The upper end of the actuating rod 44 is in engagement with the underside of a lip element 48 (FIG. 5) which extends laterally from an arcuated pawl release finger 50 which is pivotably mounted on the loomside by any suitable means not shown. The free end of this finger 50 is identified by numeral 52 and extends to a position which locates it beneath a laterally extending pin 54 carried by the feed pawl 26. By pressing on the foot pedal 42 it will pivot in a clockwise direction as viewed in FIG. 1 causing the actuating rod 44 to move in an upwardly direction. This movement will pivot the release finger 50 upwardly causing its free end 52 to engage the pin 54 and lift the feed pawl 26 out of engagement with the teeth of the ratchet wheel 18.
A conventional handwheel 56 is fixed on the outer end of the shaft 20 by means of a nut 58 and provides a well known means for manual manipulation of the take-up mechanism.
The mechanism according to the invention includes among its various parts a bell crank lever that is identified generally by numeral 60 and which is pivotably mounted on shaft 20 intermediate the ratchet wheel 18 and the hand wheel 56. A first arm 62 of this bell crank lever 60 extends in a generally downwardly direction and has a control pawl 64 pivotably mounted on the lower end thereof which extends into operative engagement with the teeth of the ratchet wheel 18. The second arm of the bell crank lever 60 is depicted by numeral 66 and is provided intermediate its ends with a pair of integrally formed and spaced bosses 68. Each of the bosses 68 is provided with a hole which is in alignment one with the other and by means of a pin 70 assembled therein the lower end of a control handle 72 is pivotably supported between said bosses. As shown in FIG. 4, the control handle 72 is spring biased in the direction of the loomside 10 by means of a coil spring 74 which interconnects said control handle with the upper end of the second arm 66 of the bell crank lever 60.
The control handle 72 extends upwardly through an elongated opening 76 provided in a bracket member generally indicated by numeral 78 which is supported above the bell crank lever 60 by means of extensions 80 and 82 which attach to the loomside 10 by means of bolts 84 and 86 respectively. This bracket member is formed by three segments 88, 90 and 92 that are joined end to end and have a cross sectional configuration that is generally L shaped with one leg of each segment extending in a downwardly direction. As shown in FIGS. 2 and 5 the center segment 90 is horizontally disposed and the segments 88 and 92 forming the ends of the bracket member are inclined downwardly from the ends of said center segment. The elongated opening 76 is formed by the combination of the three segments 88, 90 and defines a track within which the control handle is selectively movable. The downwardly extending leg of each of the segments 88, 90 and 92 is provided with an elongated slot and respectively they are identified by numerals 94, 96 and 98 (FIGS. 2 and 5). Each of the elongated slots 94, 96 and 98 have a selectively positionable pin member assembled therein which are depicted by numerals 100, 102 and 104 respectively. The portion of each pin which passes through its respective elongated slot is of reduced size and threaded and as shown in FIG. 4 they are provided with a washer 106 and nut 108 for maintaining them in their selected positions.
Pin member 102 is of shorter length than pin members 100 and 104 and being assembled in the elongated slot of segment 90, it defines the control handle's neutral position or that position where it is located during actual loom operation. Pin member 100 defines the control handle's first position which when selectively moved to that position is effective in advancing the fell of the fabric from that position depicted by line A--A to line B--B in FIG. 3.
In FIG. 3 the loom's lay beam is shown at 110 and the reed carried thereby is depicted by numeral 112. Selective movement of the fell to the position of line B--B in FIG. 3 locates it forwardly of said reed's beat-up position so as to prevent its contact with said fell when turning a loom over to a shed opening containing a broken pick of weft.
Pin member 104 defines the control handle's second position which when moved thereto permits the fell to return to the proper position for receiving the next pick when starting the loom. As with pin member 100, the position of the pin member 104 is pre-selected for a particular type of fabric being woven and its selected location is determined so that the amount the loom was turned over to repair a broken pick is compensated for when determining the distance the fell must move to return to the proper position for receiving the next pick.
To summarize the operation, an operator upon stoppage of a loom as a result of a weft break, pivots the control handle 72 to the left so as to clear the end of the pin member 102 and then pushes said handle to its first position where it is in contact with pin member 100. This movement causes the control pawl 64 to rotate the ratchet wheel 18 and through its operative connection with the cloth roll 14, the fabric and fell line thereof are advanced so as to position said fell line forwardly and clear of the beat-up position of the loom's reed 112. The loom is then turned over in the usual manner to the shed opening containing the broken pick. After repairing the broken pick the operator actuates the foot pedal 42 to effect release of the feed pawl from engagement with the teeth of the ratchet wheel 18. At the same time the foot pedal is actuated the operator with one hand releases the hold-back panel 34 by pulling forwardly on the ear 35 thereof and with the other hand pulls the control handle 72 to its second position where it is in engagement with pin member 104. This movement permits the fabric and fell to move rearwardly by means of the tension placed thereon when it was moved forwardly by the control pawl 64 and the pre-selected position of the pin member 104 compensates for the amount the loom was turned over to repair the broken pick so that the fell moves rearwardly to the precise position for the next pick.
The loom is then started and as the pick wheel is rotated by the pawl elements of the take-up mechanism, the control handle 72 advances to its neutral or loom operating position.
Although the present invention has been described in connection with a preferred embodiment, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and the appended claims.
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An improved start mark preventer for looms formed by a manually operable device including a double armed lever having a control handle mounted on one arm and a control pawl on the other arm. The control pawl is disposed in operative engagement with the loom's ratchet wheel which rotates its take-up roll by means of a feed pawl and hold-back pawl. The device includes a guide for the control handle with selectively positionable stop members that provide a neutral, first and second positions for the handle. Movement of the handle to the first position moves the fell forwardly of the reed's beat-up position, in the second position the fell is permitted to return to its initial position and upon starting the loom the control handle will automatically move to its neutral position.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the invention
[0002] The present invention relates to an optical transceiver for reducing crosstalk and, more particularly, to an optical transceiver for reducing crosstalk, which is implemented by mounting both a light transmitting device and a light receiving device on a single substrate.
[0003] 2. Description of the Prior Art
[0004] Recently, new services have been realized more and more, such as multimedia high-speed Internet, video conference, IP telephony, video on demand (VOD), internet game, telecommuting, electronic commerce, distance learning and teaching, telemedicine, and etc., and transmission capacity of a backbone network has greatly increased. However, there has been little changes in the transmission capacity of a subscribe network. This means that a bottleneck may occur between the backbone network and the subscribe network in providing various multimedia services by the subscribe network. It is not easy to remove the bottleneck by using x digital subscribe line (xDSL) and cable modem for a subscribe network solution, which is most widely used now. Thus, there is a need for a passive optical network (hereinafter referred to as PON) as a new technology, which can be manufactured at low costs, has a simple network structure and high compatibility, and can deal with all of data, audio, and video services.
[0005] The PON technologies are classified into two types; one is asynchronous transfer mode (hereinafter referred to as ATM) PON and the other is Ethernet PON. The ATM PON has been developed for incorporation of IP data, video, and high-speed services such as 10/100 Mbps Ethernet, and for providing the incorporated information with low-cost and high-speed. However, the ATM PON is not applicable to the subscribe network, because it has incapacity of video transmission, an insufficiency of bandwidth, high complexity, high cost, etc. For these reasons, technologies such as high-speed Ethernet, gigabit Ethernet and so on have been developed, and thus the Ethernet PON having a bandwidth of 1.25 Gbps has been introduced.
[0006] The optical transceiver is connected to an optical fiber, and comprised of a light signal transmitting unit having a planar lightwave circuit (hereinafter referred to as PLC), a photoelectric transducer having a light transmitting device and a light receiving device, and an electronic component having a pre-amplifier and a light transmitting device driving circuit. In the case of the transceiver components being hybrid-integrated, an electrical crosstalk occurs, i.e., a high-speed signal from the light-transmitting device has an effect on the operation of the light-receiving device. The electrical crosstalk makes an operation range of the light receiving device to be limited due to a great reduction in reception sensitivity of the light receiving device, so that entire operating performance of the optical transceiver may be deteriorated. Particularly, the electrical crosstalk is seriously increased in the case of a high-speed signal. Therefore, it is required to develop the optical transceiver capable of reducing the electrical crosstalk to develop a high-speed optical transceiver such as an optical transceiver for the Ethernet PON mentioned above.
[0007] Hereinafter, an optical transceiver according to a prior art will be described with reference to FIGS. 1 and 2 .
[0008] FIG. 1 is a schematic configuration diagram of an optical transceiver for reducing crosstalk, by using a technology for increasing a space between a light transmitting device and a light receiving device, and a technology for forming a central ground line between the light transmitting device and the light receiving device, according to a prior art. FIG. 2 is a schematic configuration diagram illustrating a portion of the optical transceiver shown in FIG. 1
[0009] The optical transceiver according to the prior art is composed of a light signal transmitter 1100 , a photoelectric transducer 1200 , a substrate 1300 , a leadframe 1400 , a package encapsulant 1500 , and a leadframe pad 1600 .
[0010] The light signal transmitter 1100 transmits a light signal received from an optical fiber 1700 to a light receiving device 1260 , and transmits a light signal generated from a light transmitting device 1210 to an optical fiber 1700 .
[0011] The photoelectric transducer 1200 converts a light signal into an electrical signal, and vice versa. And, the photoelectric transducer is comprised of the light transmitting device 1210 for converting the electrical signal into the light signal, a high-speed signal line 1220 for the light transmitting device, a bias line 1230 for the light transmitting device, a monitor photo detector (MPD) 1240 for monitoring optical power of the light transmitting device 1210 , a signal line 1250 for the MPD, the light receiving device 1260 for converting the light signal into the electrical signal, a high-speed signal line 1270 for the light receiving device, a bias line 1280 for the light receiving device, and a central ground line 1290 .
[0012] The leadframe 1400 , the package encapsulant 1500 , and the leadframe pad 1600 are necessary components to easily mount on a printed circuit board (PCB) when forming a module.
[0013] The optical transceiver according to the prior art prevents interference between the light transmitting device 1210 and the light receiving device 1260 by widening a physical space between the light transmitting device 1210 and the light receiving device 1260 and by forming the central ground line 1290 between the light transmitting device 1210 and the light receiving device 1260 .
[0014] According to the prior art, it is possible to mount the optical transceiver on a small form factor pluggable (SFP) package as a standard module for the PON, when the operating speed reaches up to several hundred Mbps. However, when the operating speed becomes several Gbps, there is a problem that the optical transceiver cannot be mounted on the SFP package since the physical space between the light transmitting device 1210 and the light receiving device 1260 becomes increased up to several tens of millimeters. Further, the central ground line 1290 disposed between the light transmitting device 1210 and the light receiving device 1260 may be efficient only in case that it is assumed as a general dielectric since conductivity as an electrical characteristic of a silicon substrate on which the light transmitting device 1210 and the light receiving device 1260 are mounted is very low. However, there is a problem that a substrate having very high conductivity takes much expense, thereby it cannot be implemented with low costs.
SUMMARY OF THE INVENTION
[0015] Accordingly, the present invention is contrived to solve the aforementioned problems. The present invention is directed to an optical transceiver for reducing crosstalk.
[0016] Further, the present invention is directed to an optical transceiver having a narrower physical space between a light transmitting device and a light receiving device.
[0017] Further, the present invention is directed to an optical transceiver that can be implemented on a silicon substrate having a resistivity of 10 Ohm commonly used.
[0018] Further, the present invention is directed to an optical transceiver having both of a crosstalk characteristic of −90 dB or less and a reflection characteristic of −10 dB or less so as to be suitable for an Ethernet PON for 1.25 Gbps.
[0019] One aspect of the present invention is to provide an optical transceiver, comprising: a photoelectric transducer implemented on a substrate and having a light transmitting device for converting an electrical signal into a light signal, a high-speed signal line for the light transmitting device, a bias line for the light transmitting device, a light receiving device for converting the light signal into the electrical signal, a high-speed signal line for the light receiving device, a bias line for the light receiving device, a first dummy ground line located adjacent to the high-speed signal line for the light transmitting device, and a second dummy ground line located adjacent to the high-speed signal line for the light receiving device; and a light signal transmitter connected to the photoelectric transducer, transmitting a light signal received from an optical fiber to the light receiving device, and transmitting a light signal generated from the light transmitting device to the optical fiber.
[0020] In a preferred embodiment of the present invention, the optical transceiver may further comprise a package encapsulant attached to the substrate; a leadframe pad located inside the package encapsulant; and a plurality of leadframes connected to the high-speed signal line for the light transmitting device, the bias line for the light transmitting device, the high-speed signal line for the light receiving device, the bias line for the light receiving device, the first dummy ground line, the second dummy ground line, and the leadframe pad, respectively. In addition, the photoelectric transducer further comprises a monitor photo detector (MPD) and a monitor photo detector (MPD) signal line for monitoring optical power of the light transmitting device.
[0021] Here, the substrate is composed of a silicon substrate having a silicon oxide film. The high-speed signal line for the light transmitting device is located between the bias line for the light transmitting device and the first dummy ground line, and the high-speed signal line for the light receiving device is located between the bias line for the light receiving device and the second dummy ground line.
[0022] Here, the space between the high-speed signal line for the light transmitting device and the first dummy ground line is less than or equal to the space between the high-speed signal line for the light transmitting device and the bias line for the light transmitting device, and the space between the high-speed signal line for the light receiving device and the second dummy ground line is less than or equal to the space between the high-speed signal line for the light receiving device and the bias line for the light receiving device. And, the first and the second dummy ground lines are located outside the photoelectric transducer, and the bias lines for the light transmitting device and the light receiving device are located inside the photoelectric transducer.
[0023] Meanwhile, the first dummy ground line is located between the high-speed signal line for the light transmitting device and the bias line for the light transmitting device, and the second dummy ground line is located between the high-speed signal line for the light receiving device and the bias line for the light receiving device. The light transmitting device is a laser diode and the light receiving device is a photo diode. And, the light signal transmitter is composed of a planar lightwave circuit (PLC).
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The above and other objectives, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0025] FIG. 1 is a schematic configuration view showing an optical transceiver according to a prior art;
[0026] FIG. 2 is a schematic configuration view showing a portion of an optical transceiver according to a prior art;
[0027] FIG. 3 is a schematic configuration view showing an optical transceiver according to a preferred embodiment of the present invention;
[0028] FIG. 4 is a schematic configuration view showing a portion of the optical transceiver according to a preferred embodiment of the present invention;
[0029] FIG. 5 is a graph showing a crosstalk characteristic and a reflection characteristic of the optical transceiver according to a prior art; and
[0030] FIG. 6 is a graph showing a crosstalk characteristic and a reflection characteristic of the optical transceiver according to a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0031] Hereinafter, the present invention will be described with reference to the accompanying drawings. As many apparently widely different embodiments of the present invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the below specific embodiments thereof. Embodiments of the present invention are to provide to more fully explain the present invention to those skilled in the art.
[0032] FIG. 3 is a diagram showing a schematic configuration of an optical transceiver in accordance with a preferred embodiment of the present invention. FIG. 4 is a schematic configuration view showing a portion of the optical transceiver shown in FIG. 3 .
[0033] The optical transceiver shown in FIGS. 3 and 4 is comprised of a light signal transmitter 2100 , a photoelectric transducer 2200 , a substrate 2300 , a leadframe 2400 , a package encapsulant 2500 , and a leadframe pad 2600 . The optical transceiver may include other electronic components (not shown).
[0034] The light signal transmitter 2100 is adapted to transmit a light signal received from an optical fiber 2700 into a light receiving device 2260 , and transmit a light signal generated from a light transmitting device 2210 into the optical fiber 2700 . The light signal transmitter 2100 has a planar lightwave circuit (PLC) 2110 , for example. Two ends of the Y-branch shaped PLC 2110 are connected to the light transmitting device 2210 and the light receiving device 2260 , respectively.
[0035] The photoelectric transducer 2200 is adapted to convert a light signal into an electrical signal, and vice versa. The photoelectric transducer 2200 is comprised of the light transmitting device 2210 for converting the electrical signal into the light signal, a high-speed signal line 2220 for the light transmitting device, a bias line 2230 for the light transmitting device, a monitor photo detector (MPD) 2240 for monitoring optical power of the light transmitting device 2210 , a signal line 2250 for the MPD, the light receiving device 2260 for converting the light signal into the electrical signal, a high-speed signal line 2270 for the light receiving device, a bias line 2280 for the light receiving device, a first dummy ground line 2290 , and a second dummy ground line 2295 .
[0036] The light transmitting device 2210 and the light receiving device 2260 are connected to both ends of the PLC 2110 , respectively. The light transmitting device 2210 converts an electrical signal inputted from an external driving circuit (not shown) into a light signal having a wavelength bandwidth of, e.g., 1.3 micrometers (μm), and then transmits the light signal to the other optical transceiver (not shown) through the PLC 2110 and the optical fiber 2700 . The light receiving device 2260 converts an light signal having a wavelength bandwidth of e.g., 1.5 μm, inputted from the other optical transceiver through the PLC 2110 and the optical fiber 2700 into an electrical signal, and then transmits the electrical signal to a pre-amplifier (not shown) mounted on the outside. The light transmitting device 2210 may be a laser diode, and the light receiving device 2260 may be a photo diode. The driving circuit and the pre-amplifier may be comprised in an electric circuit (not shown).
[0037] The first dummy ground line 2290 and the second dummy ground line 2295 are located adjacent to the high-speed signal line 2220 for the light transmitting device and the high-speed signal line 2270 for the light receiving device, respectively. When the space between the first dummy ground line 2290 and the high-speed signal line 2220 for the light transmitting device is less than or equal to the space between the bias line 2230 for the light transmitting device and the high-speed signal line 2220 for the light transmitting device, and the space between the second dummy ground line 2295 and the high-speed signal line 2270 for the light receiving device is less than or equal to the space between the bias line 2280 for the light receiving device and the high-speed signal line 2270 for the light receiving device, noise components of the high-speed signal line 2220 for the light transmitting device and the high-speed signal line 2270 for the light receiving device are primarily coupling to each of the first dummy ground line 2290 and the second dummy ground line 2295 , resulting in reducing the electrical crosstalk. For example, as shown in FIG. 4 , the space between the high-speed signal line 2220 for the light transmitting device and the first dummy ground line 2290 can be designed to be 0.5 times less than the space between the bias line 2230 for the light transmitting device and the high-speed signal line 2220 for the light transmitting device, and the space between the high-speed signal line 2270 for the light receiving device and the second dummy ground line 2295 can be designed to be 0.5 times less than the space between the bias line 2280 for the light receiving device and the high-speed signal line 2270 for the light receiving device.
[0038] As shown in the figures, the bias line 2230 for the light transmitting device and the first dummy ground line 2290 can be located at both sides of the high-speed signal line 2220 for the light transmitting device, respectively, and the bias line 2280 for the light receiving device and the second dummy ground line 2295 can be located at both sides of the high-speed signal line 2270 for the light receiving device, respectively. In this case, as shown in the figures, the bias line 2230 for the light transmitting device and the bias line 2280 for the light receiving device can be located inside the photoelectric transducer 2200 , and the first dummy ground line 2290 and the second dummy ground line 2295 can be located outside the photoelectric transducer 2200 . Here, the space between the first dummy ground line 2290 and the high-speed signal line 2220 for the light transmitting device must be less than or equal to the space between the bias line 2230 for the light transmitting device and the high-speed signal line 2220 for the light transmitting device. Also, the space between the second dummy ground line 2295 and the high-speed signal line 2270 for the light receiving device must be less than or equal to the space between the bias line 2280 for the light receiving device and the high-speed signal line 2270 for the light receiving device.
[0039] Meanwhile, the first dummy ground line 2290 can be located between the high-speed signal line 2220 for the light transmitting device and the bias line 2230 for the light transmitting device, the second dummy ground line 2295 can be located between the high-speed signal line 2270 for the light receiving device and the bias line 2280 for the light receiving device.
[0040] A silicon substrate having a silicon oxide film with a thickness of several μm on the substrate may be desirably used as the substrate 2300 .
[0041] The leadframe 2400 , the package encapsulant 2500 , and the leadframe pad 2600 are necessary components to easily mount on the PCB when forming a module. Leadframes corresponding to reference numerals 2410 , 2420 , 2430 and 2440 of the leadframe 2400 are connected to the ground. Unlike FIG. 2 , the leadframes for reference corresponding to reference numerals 2420 and 2430 are not connected to additional central grounds on the substrate, and they are connected to the leadframe 2600 , and used to support it mechanically and reduce parasitic components in only the leadframe 2400 . The leadframe 2400 may be a lead frame of a family of Alloy42, for example.
[0042] Hereinafter, a preferred embodiment of the present invention will be compared with the prior art in reference to FIGS. 5 and 6 .
[0043] FIG. 5 illustrates a crosstalk characteristic and a reflection characteristic of the optical transceiver manufactured in accordance with the prior art shown in FIGS. 1 and 2 . In this optical transceiver, the space between the light transmitting device and the light receiving device is 8.09 mm, and the entire width of the optical transceiver is 10.5 mm. From FIG. 5 , it can be noted that the crosstalk characteristic in the frequency of 1.25 GHz is less than −90 dB so as to satisfy the module receiving sensitivity of −26 dBm, and the reflection characteristic in the frequency of 1.25 GHz is less than −10 dB so as to connect to a 50 Ohm system.
[0044] FIG. 6 illustrates a crosstalk characteristic and a reflection characteristic of the optical transceiver manufactured by the embodiment of the present invention shown in FIGS. 3 and 4 . In this optical transceiver, the space between the light transmitting device and the light receiving device is 4.7 mm, and the entire width of the optical transceiver is 8.4 mm. From FIG. 6 , it can be appreciated that the optical transceiver according to the present invention is applicable to the Ethernet PON optical transceiver for 1.25 Gbps, since the crosstalk characteristic and the reflection characteristic in the frequency of 1.25 GHz are less than −90 dB and −10 dB, respectively, as similar with FIG. 5
[0045] As described above, in view of the crosstalk characteristics and the reflection characteristics in the frequency of 1.25 GHz in accordance with the prior art and the present invention, the optical transceiver manufactured by the present invention can obtain reduction of about 40% in the space between the light transmitting device and the light receiving device, and reduction of about 20% in the width of the optical transceiver, as compared with the optical transceiver manufactured by the prior art.
[0046] The optical transceiver according to the present invention has advantages that can remove the electrical crosstalk with holding the physical space between the light transmitting device and the light receiving device close to each other, by forming the dummy ground lines to be adjacent to the light transmitting device and the light receiving device.
[0047] In addition, the optical transceiver according to the present invention can make use of a silicon substrate having a resistivity of 10 Ohm commonly used in the technical field. Also, it may has the advantage that the module can reduce about 20% of its size by using this substrate, as compared with the prior art, even in the case of manufacturing the optical transceiver for an Ethernet PON having the crosstalk characteristic of less than −90 dB and the reflection characteristic of less than −10 dB, respectively in the frequency of 1.25 GHz.
[0048] Furthermore, the optical transceiver according to the present invention has advantages that it is adaptable for production in mass quantities without changing any production lines, since it can be easily implemented and there are no additional components required.
[0049] Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
[0050] The present application contains subject matter related to korean patent application No. 2003-62417, filed in the Korean Patent Office on Sep. 6, 2003, the entire contents of which being incorporated herein by reference.
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Provided is an optical transceiver for reducing crosstalk, comprising a light signal transmitter, a photoelectric transducer having a light transmitting device that converts the electrical signal into the light signal for transmission and a light receiving device that converts a received light signal into an electrical signal, and an electronic component that is located on a PCB connected to a leadframe or inside the optical transceiver module and amplifies, modulates, and demodulates the electrical signals in receiving and transmitting, whereby it is possible to implant the crosstalk level of less than −90 dB capable of retaining the reception sensitivity to −26 dBm in the optical transceiver, by forming the dummy ground lines on the substrate to reduce the crosstalk between the light transmitting device and the receiving device mounted on the silicon substrate.
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RELATED APPLICATIONS
[0001] This application is a continuation application of co-pending U.S. patent application Ser. No. 12/981,930 entitled Method And System For Providing A Fixed Rate Annuity With A Reset Interest Rate Feature, filed Dec. 30, 2010 which is a continuation application of U.S. patent application Ser. No. 12/701,745, now U.S. Pat. No. 7,873,554, entitled Method And System For Providing A Fixed Rate Annuity With A Lock-In Interest Rate Feature, filed Feb. 8, 2010, which is a continuation application of U.S. patent application Ser. No. 11/787,493, now U.S. Pat. No. 7,660,757, entitled Method And System For Providing A Fixed Rate Annuity With A Lock-In Interest Rate Feature, filed Apr. 16, 2007, the entire contents of each of which are herein incorporated by reference for all purposes.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method and system for providing a client with the benefit of a fixed rate annuity, offering both a static, guaranteed rate for a multi-year period, as well as a rate which fluctuates periodically (reset rate); more particularly, to a method and system wherein a client initially selects the reset rate while retaining a one time option, exercised manually or automatically, to switch to, or lock in, the guaranteed interest rate for the remainder of the contract term, when the reset rate falls below the guaranteed rate.
[0004] 2. Description of the Prior Art
[0005] A deferred annuity is typically used to provide accumulation and, potentially, a future stream of annuity income. The deferred annuity comprises an accumulation period during which the account value will vary with the underlying investments. Deferred annuities typically provide guaranteed income for life which transfers some portion or all of the risk of outliving ones accumulated assets to the insurer.
[0006] One basis for distinguishing commonly available deferred annuities is whether the annuity is classified as a “fixed annuity” or a “variable annuity”. In a fixed annuity, the insurer guarantees a fixed rate of interest applicable to each annuity deposit. Therefore, a fixed annuity is desirable for those seeking a “safe” investment. The guaranteed interest may apply for a specified period of time, often one year or more. Often, a rate guaranteed for more than one year is called a “multi-year guarantee” (MYG rate). The rate credited on a fixed annuity is reset periodically, moving in an amount and a direction that correlates with the yields available on fixed-income investments available to the insurer. The rate may also be adjusted based upon an external index. For a given term, fixed annuities typically only offer clients the fore-mentioned guaranteed rate of interest for multi-years (MYG rate) or alternatively, an initial rate that can be reset periodically (typically annually). The MYG rate is often lower than the reset rate because the insurer has less flexibility. A client must select only one of these options during a contract term.
[0007] Thus, typically, a client seeking a high rate of return, who selects a fixed annuity, elects to receive rates that can be reset periodically, and faces the risk that the issuing company may significantly lower rates at the end of each period within the life of the contract. This exposure to risk reduces the attractiveness of the annuity as an investment. Potential clients who require a certain level of income in retirement, and will be depending upon the annuity to supply that income, may seek other investments, outside of the annuity market, without that potential exposure.
[0008] Thus, there remains a need in the art for a data processing method, for administering an annuity product for a contract term, wherein the annuity product has a lock-in feature that provides a guarantee that the interest payable will not fall below a guaranteed interest rate, should adjustable rates be significantly reset downwards. In addition, there is needed an annuity product wherein a guaranteed interest rate is automatically applied to the account balance of the annuity, when an adjustable interest rate payable falls below the guaranteed interest rate, so that the client need not concern himself or herself with the fluctuations in the adjustable rate.
SUMMARY OF THE INVENTION
[0009] The present invention provides a data processing method and system for administering a deferred annuity product during the accumulation phase of a contract term, wherein the annuity product permits the client to select both an interest rate which is reset periodically (reset rate) and an interest rate guaranteed for multiple years (MYG rate), during the same contract term. If the consumer selects the reset rate initially, typically the consumer is earning a higher rate of interest on the consumers premiums than that which is provided by the MYG rate but is also assuming a risk that the reset rate will decrease.
[0010] The insurer adjusts the reset rate at its discretion or based upon an external index. The insurer declares the reset rate in advance of its effective date and at any point in time, it may be lower than the MYG rate, which is applied on the day the annuity contract is issued. In the event the reset rate is lower than the MYG rate, the client has the option of electing that the MYG rate be applied, from that point forward, to the client's account balance. In another embodiment of the invention, the election may be made automatic such that once the reset rate falls below the MYG rate, no action on the client's part is required to change the interest rate to the guaranteed, MYG rate. The election of the MYG rate, subsequent to the election of the reset rate, is a one-time option and applies until the end of the contract term, regardless of whether the election is automatic or initiated by the client.
[0011] The present invention solves several of the problems associated with conventional administration of annuity products. It provides an annuity product, system, and method, which will reduce the risk of annuitants who elect to receive adjustable rates that can be reset periodically. Specifically, it provides an annuity product, system, and method containing a lock-in feature providing a guarantee that the adjustable interest rate payable to the client will not fall below a declared guaranteed interest rate, should the adjustable interest rate be significantly reset downwards. It also provides an annuity product, system, and method including this lock-in feature, as an option for the annuitant to exercise at will, or as an automatic feature elected upon issue of the annuity.
BRIEF DESCRIPTION OF DRAWINGS
[0012] The invention will be more fully understood and further advantages will become apparent when reference is had to the following detailed description of the preferred embodiments and the accompanying drawings, in which:
[0013] FIG. 1 is a flow chart illustrating a preferred embodiment of the present invention comprising a data processing method for administering an annuity product with a rate lock-in feature; and
[0014] FIG. 2 is a diagram of a system for administering a preferred embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] The present invention comprises a data processing system and method for administering an annuity product containing a lock-in interest rate feature. The system, method, and product provide the client with both the benefit of an adjustable interest rate, which reflects the movement of an external measure or insurer discretion, as well as a guaranteed interest rate. According to the invention, the lock-in feature insures that the interest rate payable to the client will not fall below a declared guaranteed interest rate, should the adjustable rate be significantly reset downwards. The client may select the lock-in as an automatic feature, elected upon issue of the annuity, or return the right to pick and choose, if and when, the guaranteed interest rate feature will be applied. The unique combination of these two capabilities makes the present invention a superior investment choice for clients, who wish to insure that their annuity accumulates enough to provide an adequate payout stream but at the same time, do not wish to absorb the significant risk that the interest rate they receive falls below a declared minimum level.
[0016] FIG. 1 is a flow chart illustrating a preferred embodiment of the present invention comprising a data processing method for administering an annuity product with an interest rate lock-in feature. It should be understood that the order of the successive method steps is shown for the sake of illustrating but one example and that the order of method steps can proceed in any variety of orders. In step 110 , the client selects the type of interest rate the client wishes to be applied to the client's premiums, during the accumulation phase of the fixed rate annuity. If the client wishes to absorb no risk at all, the client selects a guaranteed interest rate (MYG rate) for the guaranteed period. Typically the guaranteed period is several years or more.
[0017] In step 110 , the client may also select to have an adjustable rate (reset rate) applied to the client's premiums during the accumulation phase. The insurer declares this rate periodically, typically annually. The rate declared may be higher, lower, or equal to the MYG rate and is typically based upon an external index; however, the insurer may use its own discretion in selecting the rate percent. The client may also select a third choice, unique to this product, to have the insurer automatically apply the reset rate to the client's premium, until such time as the reset rate falls below the MYG rate. Should this event occur, the client's accumulated account balance earns interest at the MYG rate, until the end of the contract term. This automatic transfer is a one-time event. In accordance with this third option, the reset rate is no longer available as an option for the client, once the client has transferred to the MYG rate. In an alternate embodiment, this automatic option is not available to the client and the client must manually request the transfer of funds and the application of the MYG rate for the remainder of the contract term.
[0018] In step 120 , the insurer calculates the interest credits the client has accumulated at the end of each period, by multiplying the account value by the selected rate. The insurer adds the interest credits to the existing account value to generate a new accumulated account value. In step 130 , periodically, the insurer checks to see whether the reset rate has been selected, if it has, the insurer proceeds with step 140 . In step 140 , the insurer compares the reset rate with the MYG rate to see if the reset rate is the lower of the two rates. If not, the insurer applies the rate selected, i.e. the reset rate. If the reset rate is now lower than the MYG rate, the insurer proceeds to step 150 .
[0019] In step 150 , the insurer checks to see whether the client has selected the automatic option. If yes, the insurer applies the MYG rate to the client's premium and the account balance is earmarked for application of the MYG rate for the remainder of the contract term. If the client has not selected the automatic option, the insurer proceeds to step 170 . In step 170 , the client has the option of continuing to have the reset rate applied to the client's premium and account balance or changing to the MYG rate. If the client decides to select the MYG rate, this is a one-time only change, which will be applied to the client's account balance for the remainder of the contract term.
[0020] FIG. 2 is a diagram of a system for administering the present invention. The software for implementing the method and product resides on a computer 20 . The data including the account value of each client, the type of interest rate selected, the MYG, interest credits earned, date of each rate adjustment (anniversary), as well as additional client information is stored in permanent storage 10 . This may take the form of tape, disk, 15 flash memory and other well-known forms of digital storage. A keyboard 30 is used to input changes to the system 20 , such as when the client selects a new form of interest rate. However, any standard input tool such as a mouse, card reader, wireless signal, etc. can be used with the system 20 .
[0021] Table 1, set forth below, further illustrates how the lock-in feature would work in accordance with the present invention, when applied to a 7-year, fixed annuity, issued in this instance on Dec. 31, 2006.
[0000]
TABLE 1
An-
Annual
nual
Reset
Guaranteed
Account
Reset
MYG
Interest
Bucket
Bucket
Value
Rate
Rate
Credits
Anniversary
Dec. 31, 2006
100,000
—
100,000
4.2%
4.0%
Dec. 31, 2007
104,200
—
104,200
4.4%
4.0%
4,200
Dec. 31, 2008
108,785
—
108,785
4.6%
4.0%
4,585
Dec. 31, 2009
113,789
—
113,789
4.8%
4.0%
5,004
Dec. 31, 2010
119,251
—
119,251
4.5%
4.0%
5,462
Dec. 31, 2011
124,617
—
124,617
3.0%
4.0%
“Lock-In”
Dec. 31, 2011
—
124,617
124,617
3.0%
4.0%
5,366
Dec. 31, 2012
—
129,602
129,602
5.0%
4.0%
4,985
Dec. 31, 2013
—
134,786
134,786
5,184
[0022] The system deposits client funds in the annual reset bucket to earn the initial rate (reset rate) of 4.2% as of Dec. 31, 2006. At this point in time, the reset rate of 4.2% exceeds the MYG rate. On the first anniversary, Dec. 31, 2007, the reset rate rises to 4.4% while the MYG rate remains static at 4.0%. The client, at this point, has earned 4,200 interest credits generated by multiplying the reset rate of 4.2% by the account value of $100,000. The interest credits, or 4,200, are added to the amount in the annual reset bucket ($100,000), yielding $104,200, the account value as of Dec. 31, 2007.
[0023] On the second anniversary, Dec. 31, 2008, the reset rate is raised, once again, to 4.6%. By this time, 4,585 interest credits have been earned by multiplying 4.4%, the year 2007 interest rate, by the year 2007 account balance of $104,200. The interest credits are added to the account value yielding an account value of $108,785 as of Dec. 31, 2008. This process is repeated in years 2008, 2009, and 2010.
[0024] In year 2011, the lock-in feature of the present invention takes effect. As of Dec. 31, 2011, the reset rate falls to 3.0%, which is lower than the MYG rate of 4.0%. At this point, if the automatic option has been selected by the client, or if the client manually elects the lock-in option, the client's interest rate switches to the MYG rate. Accordingly, for the following year, year 2012, the interest applied is not the reset rate of 3.0% but rather, the MYG rate of 4.0%. Instead of earning $3,739, which would correspond to an interest rate of 3.0%, the account value earns $5,366, which corresponds to an interest rate of 4.0%. Furthermore, the account value from this date forward until the end of the contract, in this case year 7, earns interest credits corresponding to the credits earned using the MYG rate as a multiplier.
[0025] A data processing method for administering a deferred annuity product for an annuitant, during the accumulation phase of a contract term, the annuity product having a contract value, a guaranteed interest rate, and a reset interest rate, includes the steps of: a. during the accumulation phase: i. declaring a guaranteed interest rate for a guaranteed period; ii. at predetermined intervals, determining a reset interest rate, wherein the reset interest rate may be equal to the guaranteed interest rate, higher than the guaranteed interest rate, or lower than the guaranteed interest rate; iii. applying the guaranteed interest rate to premiums deposited into a guaranteed account for accumulating an account value; iv. applying the reset interest rate to premiums deposited into a reset account for accumulating an account value; b. in the event that the reset interest rate falls below the guaranteed interest rate: i. providing the annuitant with an option to request a transfer of the account value from the guaranteed account to the reset account, whereby the account value is calculated according to the guaranteed interest rate for the remainder of the contract term.
[0026] In an embodiment of the method, the transfer of the account value is a one-time transfer.
[0027] In an embodiment of the method, the annuitant exercises the option to request a transfer of the account balance, at the start of the contract term, and the transfer takes place automatically, when the reset interest rate falls below the guaranteed interest rate.
[0028] In an embodiment of the method, the reset interest rate is based upon an external index.
[0029] In an embodiment of the method, the reset interest rate is declared on an annual basis.
[0030] A data processing method for administering a deferred annuity account, with a declared contract period, has an interest rate earned by premiums deposited by an annuitant set to a guaranteed interest rate, declared at the time the annuity is issued, and the annuitant has the option of selecting the guaranteed rate or a reset interest rate which is declared annually, and the annuitant has the further option of selecting the reset interest rate initially and transferring the annuitant's account balance to an account earning the guaranteed interest rate, when the guaranteed rate is higher than the reset interest rate, such transfer being a one-time, irrevocable transfer lasting until expiration of the contract period.
[0031] A deferred annuity product includes: a. means for calculating and paying a guaranteed interest rate on deposited premiums to generate an account value in a first account; b. means for calculating a reset interest rate, on an annual basis, and paying the reset interest rate on deposited premiums to generate an account value in a second account; c. means for identifying when the guaranteed interest rate has a value lower than the reset interest rate; and d. means for transferring the account value from the first account to the second account for the duration of a contract term, whereby the account value earns interest at the guaranteed interest rate.
[0032] A system for administering a deferred annuity product having a predefined term and an account value, during the accumulation phase, includes: a. first interest rate means for establishing a guaranteed interest rate; b. second interest rate means for establishing a reset interest rate which is updated at predefined periods; c. first selection means for selecting the guaranteed interest rate or the reset interest rate; d. calculation means for calculating interest credits and incrementing the account value with interest credits, based upon the selected interest rate; e. second selection means for providing the annuitant with an option to request a transfer from the reset interest rate to the guaranteed interest rate, in the event that the reset interest rate is the selected interest rate and the reset interest rate falls below the guaranteed interest rate.
[0033] In an embodiment of the system, the second selection means operates automatically and the request to transfer the reset interest rate to the guaranteed interest rate, in the event that the reset interest rate falls below the guaranteed interest rate, is selected upon issuance of the annuity.
[0034] In an embodiment of the system, the reset interest rate is updated annually.
[0035] A data processing method is for administering a deferred annuity product during the accumulation phase, for a contract term, wherein the annuity product permits the consumer to select successively a first interest rate which is reset periodically and a second interest rate, guaranteed for multiple years, during the same contract term.
[0036] The detailed illustrative embodiment here presented is directed at providing a more complete understanding of the invention. The specific techniques, systems, and operating structures set forth to illustrate the principles and practice of the invention may be embodied in a wide variety of sizes, shapes, forms and modes, some of which may be quite different from those in the disclosed embodiment. Consequently, the specific structural and functional details disclosed herein are exemplary. They are deemed to afford the best embodiment for purposes of disclosure; but should not be construed as limiting the scope of the invention.
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A data processing method and system for managing interest rate calculations includes a data storage device storing data indicative of an account value of an investment product and a computer configured to determine a current value of an adjustable interest rate, compare the adjustable interest rate to a fixed guaranteed minimum interest rate, and determine whether to apply the adjustable interest rate or the fixed guaranteed minimum interest rate to the investment product account value to determine a value to credit to the account.
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BACKGROUND OF THE INVENTION
The present invention relates generally to communication networks, and more specifically, to upgrading circuits in an optical network in a non-service affecting manner.
Today, SONET/SDH is the predominant technology for transport in worldwide public carrier networks. One of the key attributes of SONET/SDH is its ability to provide network survivability in point-to-point, ring, and mesh architectures. Many networks today are based upon fiber-ring architectures, as evidenced by the proliferation of SONET/SDH rings all the way from the long-haul backbone to the metropolitan and regional areas. Ring topologies are important because SONET uses it for protection purposes. Network operators have become accustomed to the fast, timely recovery capabilities provided by SONET/SDH automatic protection switching (APS) schemes, such as unidirectional path switched rings (UPSR)/sub-network connection protection (SNCP), 1+1 and bi-directional line switched rings (BLSR).
UPSR is a closed-loop, transport architecture that protects against fiber cuts and node failures by providing duplicate, geographically diverse paths for each circuit. A UPSR network is composed of two counter rotating fiber rings; referred to as the working and protection rings. Adjacent nodes on the ring are connected by a single pair of optical fibers, which form the two counter rotating rings carrying traffic in opposite directions. Working traffic is sent on the working ring in one direction on one fiber and copies are transmitted on the protection ring in the opposite direction over the other fiber. A destination node in the ring receives two signals, one along each ring. The node monitors transmission on both fibers and performs a protection switch to the alternate path if it detects degraded transmission. In this way, when there is a single link failure, it can recover by switching to the available signal. The UPSR is simpler than the two-fiber (2F) or four-fiber (4F) BLSRs since it requires only two fibers to operate.
A 2F-BLSR network also has two counter rotating fiber rings. Each fiber pair between two nodes is a full-duplex link. In this link, half the bandwidth carries working traffic, and the other half is for protection. If there is a single link failure, the working traffic that was carried on the link is looped back around the ring using the protection bandwidth of the other links. A 4F-BLSR network is similar to the 2F-BLSR except that there are two pairs of counter rotating fiber rings. One pair is used for working traffic and the other is used for protection.
It is often desired to upgrade an unprotected optical circuit to a path protected optical circuit, or upgrade a UPSR to a BLSR. Topology upgrade of circuits involves various steps at a number of nodes in the network. Conventional systems for upgrading an optical circuit use a set of time consuming and labor intensive manual steps which may require a technician to be present at each location. Conventional methods for upgrading circuits require, for example, use of TL1 (Transaction Language 1) and involve a piecemeal upgrade of the circuit at each node. Another drawback to these conventional topology upgrade techniques is that they do not provide a network view of the circuit during the upgrade. Thus, the user has to remember each step, perform manual checks at each step, and manually perform each step on each node.
There is, therefore, a need for a method and system for providing automatic in-service circuit upgrades. It is desirable that the method and system allow for the circuit or topology of a live network to be modified or converted without losing traffic on existing circuits.
SUMMARY OF THE INVENTION
A system and method for performing a circuit upgrade in a communication network comprising network elements coupled together to form one or more circuits are disclosed. In one embodiment, the upgrade is generated at a node in communication with the circuits and the method generally comprises providing a list of circuits or spans available for upgrade at the node and receiving input from a user identifying at least one circuit to be upgraded or at least one span for the upgraded circuit and a type of upgrade to be performed. The method further comprises automatically performing the circuit upgrade.
In another aspect of the invention, a system for performing a circuit upgrade in a communication network generally comprises a graphical user interface operable to provide a user with a list of circuits or spans available for conversion at a node and receive input from a user identifying at least one circuit to be upgraded or at least one span for the upgraded circuit and a type of upgrade to be performed and a processor operable to automatically perform the upgrade at a circuit level.
The system and method may be used, for example, to upgrade a linear circuit to a UPSR or upgrade a UPSR to a 2F-BLSR.
Further understanding of the nature and advantages of the inventions herein may be realized by reference to the remaining portions of the specification and the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a block diagram of a network according to one embodiment of the present invention.
FIG. 1B is a block diagram of a conversion manager and network element according to one embodiment of the present invention.
FIG. 2A illustrates a linear 1+1 bi-directional circuit before conversion.
FIG. 2B illustrates a UPSR/SCNP circuit after conversion from the circuit shown in FIG. 2A .
FIG. 3 illustrates a linear 1+1 unidirectional circuit prior to conversion.
FIG. 4 illustrates a UPSR/SNCP circuit after conversion from the circuit shown in FIG. 3 .
FIG. 5 illustrates a linear unprotected circuit prior to conversion.
FIG. 6 illustrates a UPSR/SNCP circuit after conversion from the circuit shown in FIG. 5 .
FIG. 7 illustrates location of topology upgrade objects during conversion from an unprotected two-way circuit to UPSR.
FIG. 8 illustrates location of topology upgrade objects during conversion from an unprotected one-way circuit to UPSR.
FIG. 9 is a flowchart illustrating a process for upgrading an unprotected circuit to UPSR.
FIG. 10 illustrates a UPSR/SNCP bi-directional circuit prior to conversion.
FIG. 11 illustrates a BLSR/MSSP circuit after conversion from the circuit shown in FIG. 10 .
FIG. 12 illustrates a UPSR/SNCP bi-directional circuit with UPSR/SNCP prior to conversion.
FIG. 13 illustrates a BLSR/MSSP circuit after conversion from the circuit shown in FIG. 12 .
FIG. 14 illustrates a UPSR/SNCP circuit prior to conversion.
FIG. 15 illustrates a BLSR/MSSP unidirectional circuit after conversion from the circuit shown in FIG. 14 .
FIG. 16 illustrates a UPSR/SNCP circuit prior to conversion.
FIG. 17 illustrates a BLSR/MSSP circuit with UPSR/SNCP after conversion from the circuit shown in FIG. 16 .
FIG. 18 illustrates location of topology upgrade objects during conversion from a UPSR two-way circuit to BLSR.
FIG. 19 illustrates location of topology upgrade objects during conversion from a UPSR one-way circuit to BLSR.
FIG. 20 is a flowchart illustrating a process of the present invention for converting UPSR to BLSR.
FIG. 21 is a flowchart illustrating a process of the present invention for error recovery during conversion from UPSR to 2F-BLSR.
FIG. 22 is a system block diagram of a computer system that can be utilized to execute software of an embodiment of the present invention.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
The following description is presented to enable one of ordinary skill in the art to make and use the invention. Descriptions of specific embodiments and applications are provided only as examples and various modifications will be readily apparent to those skilled in the art. The general principles described herein may be applied to other embodiments and applications without departing from the scope of the invention. Thus, the present invention is not to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features described herein. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail.
A method and system of the present invention provide the ability to modify or convert the topology or upgrade one or more circuits of a live network without affecting traffic on existing circuits (i.e., in a non-service affecting manner). The network nodes and links may be reconfigured and the type of protection used may be changed. As described below, a GUI wizard is preferably used to step the user through the upgrade process. The GUI wizard provides a network and circuit view of the upgrade, which allows the user to automatically perform and track the upgrade on the entire circuit rather than having to use TL1 to modify and manually track the upgrade on each individual node. The system provides the user with the freedom of manually routing a protect/alternate path or automatically finds the shortest path for each circuit on a ring. As described in detail below, error recovery is an important part of each conversion. The system handles a number of critical network and system failures that may occur during the upgrade procedure and allows the user to restart the upgrade procedure and complete the upgrade. If failures occur during the conversion procedure, there is also a mechanism which allows for a rollback to the prior setup or for completion of the partially completed conversion procedure.
The present invention operates in the context of a data communication network including multiple network elements. The network may be a SONET/SDH network and a network element may be a terminal multiplexer, an add-drop multiplexer (ADM), an optical crossconnect (OXC), a signal regenerator, router, switch, or other optical node interface, for example. The system and method described herein may be incorporated, for example, into an optical transport platform, such as ONS 15327, 15454, or 15455 available from Cisco Systems, Inc.
Referring now to the drawings, and first to FIG. 1A , an example of a network that may be used in the present invention is shown. The network includes nodes (also referred to as network elements or NEs) 10 interconnected by links (spans) 12 . A network circuit can traverse one or more NEs 10 . Each intermediate NE 10 performs a cross connect function, connecting the circuit data from one link to another to deliver data to a destination. A conversion manager (CM) 14 runs on a computer connected to a NE 10 . The conversion manager may operate, for example, on a computerized network management system (NMS). The network shown in FIG. 1A may be, for example, a SONET network managed via one or more network management stations. The network shown may be part of a larger SONET/SDH network. The network elements 10 are interconnected by optical fiber links 12 which include an optical fiber cable or multiple cables connected serially, as is well known by those skilled in the art. The network elements 10 may be interconnected by more than one link 12 . Each link 12 carries one or more transport signals, (e.g., STS (Synchronous Transport Signals).
The conversion manager 14 may run on separate computers attached to NEs 10 , as shown in FIG. 1A . A network may include several conversion manager systems 14 running concurrently on the same or different computers, connected to the same or different NEs 120 . It is to be understood that the network shown in FIG. 1A is only one example and that the system and method disclosed herein may be used in various types of network configurations without departing from the scope of the invention.
The conversion manager 14 may be connected to the NE 10 by an Ethernet link 16 or some other interface (e.g., serial port, wide area network, wireless connection, or other suitable interface as is well known by those skilled in the art) ( FIG. 1B ). The conversion manager 14 queries the NEs 10 for the state of their cross-connects or other circuit information stored at the NEs. This operation may be performed in the same manner that a NMS gathers information from NEs, for example. The conversion manager 14 receives topology information (e.g., topology map) 18 from the NEs 10 and each NE preferably maintains a list of all the conversion manager systems registered with the NE. As the conversion manager 14 receives pieces of cross-connect and circuit information from the NEs 10 , the conversion manager splices these pieces together and constructs representations of network circuits in a form which makes it easy for a user to trace each circuit from its source NE through intermediate NEs to a destination. A graphical user interface (GUI) module 22 displays the circuits on a computer screen 24 . Input device 26 (e.g., keyboard, mouse) allows the user to issue commands via the GUI 22 to configure circuits in the network. The GUI module 22 may include, for example, an HTTP browser executing a Java applet loaded from one of the NEs 10 . The browser provides the user interface, and the applet may implement various functions. A wizard 28 , described in detail below, may be used to guide a user through a network upgrade using the system of the present invention. The wizard 28 is described herein as being run on a conversion manager 14 , however, it is to be understood that the wizard may be run on a user computer that operates as a typical NMS or any other network device that is in communication with the circuits to be upgraded and contains information regarding the circuits and connecting nodes.
The conversion manager (user) computer 14 , may be a stand-alone desktop computer, laptop computer, or other suitable communication device. The computer may include, for example, a CTC (Cisco Transport Controller), available from Cisco, Systems, Inc. or other sub-network interface tool that can be used for node control. The conversion manager 14 may be implemented by object oriented software using CORBA (Common Object Request Broker Interface) or other appropriate software. The NE 10 and conversion manager 14 include a processor 30 and memory 32 and may be implemented on a computer system such as described below with respect to FIG. 28 , for example.
The method and system described herein is used to upgrade (modify, convert) various types of circuits. After the upgrade is performed, the circuit may have the same paths, bandwidth, and source and destination nodes, or one or more of these may be changed. The upgraded circuit may or may not have a new topology. While in a preferred embodiment, the upgraded circuit has increased protection (e.g., unprotected circuit changed to a protected circuit or a UPSR changed to a BLSR), it is to be understood that the upgraded circuit may also have less protection than the original circuit. The upgrade is performed without losing traffic on existing circuits (i.e., network traffic is not affected for any significant amount of time). The network nodes and links may be reconfigured during the upgrade and the type of protection used may be changed. The system and method may be used, for example, to upgrade a linear circuit (i.e., network configuration that has no rings for protection and all network links are either unprotected or 1+1 protected) to a UPSR (unidirectional path switched ring) or BLSR (bi-directional line switched ring) or upgrade a UPSR/SNCP (sub-network connection protection) to a 2F-BLSR/MSSP (multi-service switching platform)). A 2F-BLSR/MSSP may also be converted to a 4F-BLSR/MSSP. The system may also be used to add or delete nodes to or from a circuit and merge rings with unprotected circuits or other rings.
More specifically, the following conversions may be performed: linear unprotected circuit to UPSR/SNCP; linear 1+1 to BLSR/MSSP; linear 1+1 to 2F-BLSR/MSSP; linear 1+1 to 4F-BLSR/MSSP; UPSR/SNCP to 2F-BLSR/MSSP; UPSR/SNCP to 4F-BLSR/MSSP; and 2F-BLSR/MSSP to 4F-BLSR/MSSP. The system may also be used to delete nodes, add nodes, or merge rings. For example, the following modifications to circuits may be performed: add node to BLSR/MSSP; delete node from BLSR/MSSP; add node to UPSR/SNCP/PPMN (Path Protected Mesh Network); delete node from UPSR/SNCP/PPMN; add node to linear 1+1; delete node from linear 1+1; and merge UPSR/SNCP rings. The following provides specific examples of some of these circuit conversions. It is to be understood that the circuit modifications (upgrades, conversions) described herein are only provided as examples and that different circuit modifications may be implemented without departing from the scope of the invention.
The first conversion example is a linear 1+1 protected topology with 2 or more nodes into a UPSR/SNCP topology. The UPSR may be a bi-directional connection with one bi-directional path that is bridged to two paths in one direction, and selects from the same two paths in the other direction. This is a topology-level conversion so that all circuits traversing the topology are affected by this single conversion operation. The conversion of a linear circuit to UPSR/SNCP does not require new spans to be added to the topology. The set of nodes that make up the linear topology under conversion may be only a subset of all the nodes in the network. Thus, only a subset of a network may be converted, rather than the entire network. A given affected circuit may enter the topology at any node and exit at any node. Likewise, a given affected circuit may have a source or destination end point at any node in the topology. Thus, a circuit may start or end from outside the scope of the topology or from within.
Selectors and bridges and their corresponding additional paths are added to the circuit connections without affecting traffic. The number and positioning of network spans in the topology remains unchanged during and after the conversion. The working and protect spans of the 1+1 links become working and protect UPSR links. Thus, a two-way connection with paths A and B is converted to a UPSR connection with paths A, B, and C. A 3-node linear 1+1 topology (A-B-C) becomes a 3-node topology with 2 adjacent interconnected UPSR/SNCP rings: ring AB and ring BC.
FIGS. 2A , 2 B, 3 , and 4 illustrate a sample conversion of linear 1+1 circuits to a UPSR/SNCP for a bi-directional circuit and unidirectional circuit, respectively. FIGS. 2A and 3 show the topology before the conversion and FIGS. 2B and 4 show the topology after the conversion.
Referring now to FIG. 2A , the original circuit prior to conversion is shown to be a 3-node linear 1+1 segment of a bi-directional circuit. The circuit contains two two-way connections (i.e., a bi-directional connection with two paths). The circuit segment to the left of the two-way connections (as viewed in FIG. 2A ) is UPSR protected. It may be the head or drop end of a UPSR/SNCP ring and contains a bi-directional connection with one bi-directional path that is bridged to two paths in one direction and selects from the same two paths in the other direction. As shown in FIG. 2B , the converted circuit includes an interconnection between two UPSR rings (identified in FIG. 2B as UPSR_UPSR) and the head or drop end of a UPSR/SNCP ring (UPSR). In each direction, the two paths flow into a selector whose output path is bridged to two paths.
FIGS. 3 and 4 illustrate conversion of a linear 1+1 unidirectional circuit to a UPSR/SNCP. FIG. 3 shows a 3-node linear 1+1 segment of a unidirectional circuit. The unidirectional circuit may have multiple drops placed anywhere along the circuit path. The linear 1+1 circuit segment is adjacent to a UPSR segment (identified as UPSR_HEAD in FIG. 3 ). The UPSR_HEAD is the head end of a unidirectional UPSR/SNCP ring and has a unidirectional connection with one input path that is bridged to two (or more) output paths. The circuit may also have two drops coming off of the rightmost node in the segment instead of the UPSR. As shown in FIG. 4 , the converted circuit includes a UPSR head end (UPSR_HEAD) and two UPSR drop-and-continue connections (identified as UPSR_DC). The UPSCR_DC is a connection with two bi-directional paths (similar to a two-way connection), but each path also flows to a selector. The selector has one (or more) unidirectional output paths.
The linear circuit to UPSR/SNCP conversions described above involve altering multiple connections along the circuit path of each affected circuit. If a failure occurs which interrupts the conversion process, the system will allow the user to undo the partial conversion or finish the conversion process. In order to provide this error recovery, state is maintained at each node (connection) during the conversion process, as described in detail below.
The next conversion example is a linear unprotected circuit to a UPSR/SNCP. This conversion is similar to the linear 1+1 to UPSR/SNCP conversion discussed above, except that the alternate UPSR/SNCP path is not explicitly defined by 1+1 protect spans. Thus, an alternate route must be calculated. The conversion is preferably performed only at the circuit level, with only one circuit being converted at a time. An alternate path for the circuit under conversion is preferably routed automatically by the system, but may also be routed manually by the user. Once the route is obtained, circuit connections are created on any intermediate nodes in the alternate path. Existing circuit connections on the original circuit path are modified, as in the case of linear 1+1 to UPSR/SNCP upgrades described above.
FIGS. 5 and 6 illustrate an unprotected circuit to UPSR/SNCP conversion. A linear unprotected segment from node A to node B ( FIG. 5 ) is converted to a UPSR/SNCP made up of nodes A, B, and C ( FIG. 6 ). The conversion is performed by adding an alternate route through existing node C (shown in phantom in FIG. 5 ), which is added to the circuit ( FIG. 6 ).
In order to provide for error recover during conversion of an unprotected circuit to a UPSR, the nodes within the circuit are provided persistent topology (circuit) upgrade objects to store the state of an in service topology (circuit) upgrade. These topology upgrade objects help the client to recover upon a loss of connection or an abnormal termination of the client. FIG. 7 illustrates how the topology upgrade objects, during conversion from an unprotected two-way circuit to UPSR, are created at only some of the nodes within the circuit. FIG. 7 shows a network having a two way circuit from node A to node C (through node B) and a new protect path for the two way circuit from node A to node C (through nodes D, E, and F). The topology upgrade objects (TU Obj.) are created only on nodes A and C. If the conversion process is terminated before it is completed (e.g., by the client or due to a system, network, or link failure), the topology upgrade objects will save the last state. These objects will show if the topology upgrade was completed on these nodes. If even one of the objects (on different nodes) has been converted then the client can proceed with the topology upgrade for the rest of the objects. If none of these objects are converted then the client can delete all the topology upgrade objects and restart the upgrade.
FIG. 8 illustrates upgrade from an unprotected one-way circuit to a UPSR. The network is similar to the one shown in FIG. 7 , except that the path from node A to node C is a one-way circuit. In this example, the topology upgrade objects are created on nodes A, B, and C.
FIG. 9 is a flowchart illustrating a process of the present invention for converting a linear unprotected circuit to UPSR/SNCP. At step 40 , an alternate path is first identified. An alternate circuit is then created (step 42 ). A topology upgrade object is created on source and destination nodes (step 44 ). The object on the source node is set at PENDING_CREATE and the object on the destination node is set at PENDING_UPGRADE. If the circuit is unidirectional then a topology upgrade object is created on intermediate nodes along the existing circuit path between the source and destination nodes and the source node topology upgrade object state is changed from PENDING_CREATE to PENDING_UPGRADE (steps 46 and 48 ). If the circuit is unidirectional then a topology upgrade is performed on intermediate nodes along the existing circuit path (step 50 ) and the connection is changed from one-way to two-way (step 52 ). A topology upgrade is performed on the source and destination nodes at step 54 . A circuit merge is performed and the topology upgrade objects are deleted on the source and destination nodes (step 56 ).
The following describes conversion of a linear 1+1 circuit to BLSR/MSSP. A linear 1+1 network with 2 or more nodes can be converted to a 2F-BLSR/MSSP or 4F-BLSR/MSSP network. Conversion of a linear 1+1 to 4F-BLSR/MSSP requires more spans to be added than conversion to a 2F-BLSR/MSSP. The circuit connections (cross-connects) need not be modified at the NE since the circuit path and its connections do not change, only the underlying line-level protection changes.
Next, examples are provided for conversion of UPSR/SNCP to BLSR/MSSP. During UPSR to BLSR conversion, all circuits on a given ring are automatically converted. For example, when a UPSR/SNCP ring is converted to 2F-BLSR/MSSP the arrangement of the ring nodes and spans remains unchanged. Circuits are converted from path protection to line protection. Only a primary path through the ring is needed, so the alternate UPSR/SNCP path is removed. This is a topology-level conversion so that all circuits traversing the topology are affected by this single conversion operation. The set of nodes that make up the UPSR/SNCP topology under conversion may be only a subset of all the nodes in the network. Thus, it is not the entire network that is being converted, but only a specific subset of the network. A given affected circuit may enter the topology at any node and exit at any node. Likewise, a given affected circuit may have a source or destination endpoint at any node in the topology, thus, a circuit may start or end from outside the scope of the topology or from within.
Circuit connections with bridges and selectors are modified at the NE. Selectors and bridges and their corresponding additional paths are removed from the circuit connections (without affecting traffic). For example, a UPSR connection with paths A, B, and C will be converted to a two-way connection with paths A and B. Also, for unidirectional circuits, two-way connections are converted to one-way connections. If the UPSR/SNCP rings are not explicitly defined, the rings must first be identified for the conversion takes place.
FIGS. 10-17 illustrate examples for converting UPSR to BLSR. FIGS. 10 and 11 illustrate UPSR/SNCP to BLSR/MSSP conversion for a bi-directional circuit. FIGS. 12 and 13 illustrate UPSR/SNCP to BLSR/MSSP conversion for a bi-directional circuit extending to other UPSR rings. FIGS. 14 and 15 illustrate UPSR/SNCP to BLSR/MSSP conversion for a unidirectional circuit. FIGS. 16 and 17 illustrate UPSR/SNCP to BLSR/MSSP conversion for a unidirectional circuit extending to other UPSR rings. FIGS. 10 , 12 , 14 , and 16 show the topology before the conversion and FIGS. 11 , 13 , 15 , and 17 show the topology after the conversion is performed. In a UPSR/SNCP to BLSR/MSSP conversion, the shorter path is retained and connections and UPSR selectors on the other path are removed ( FIGS. 10-17 ).
Conversion of UPSR/SNCP to 4F-BLSR/MSSP is similar to converting a UPSR/SNCP ring to 2F-BLSR/MSSP. However, more spans (fibers) must be added to achieve a 4-fiber ring.
As discussed above, the conversion process for UPSR/SNCP to BLSR/MSSP involves altering multiple connections along the circuit path of each affected circuit. If a failure occurs, which interrupts the conversion process, the system provides a mechanism by which the partial conversion can be reversed or completed. In order to provide for error recovery, the state at each node (connection) is preferably retained during the conversion process.
FIG. 18 illustrates location of topology upgrade objects for conversion from a UPSR two-way circuit to BLSR. The network shown in FIG. 18 includes a two-way UPSR circuit from node A to node C (through node B), which is to be retained in the BLSR circuit, and a two-way UPSR circuit from node A to node C (through nodes D, E, and F), which will be deleted in the BLSR conversion. The topology upgrade objects are created on the nodes that are part of the UPSR path that needs to be deleted or modified (i.e., path A-D-E-F-C).
FIG. 19 shows the locations of the topology upgrade objects for a UPSR one-way circuit to BLSR conversion. The path from node A to node C (through node B) of the one-way UPSR circuit is retained in the BLSR circuit. The path from node A to node C (through nodes D, E, and F) of the one-way UPSR circuit is deleted during the BLSR conversion. The topology upgrade objects are created on all the nodes. The topology upgrade object is created on node B since the connection type changes from two-way to one-way.
FIG. 20 is a flowchart illustrating a process of the present invention for converting UPSR to BLSR. At step 60 , an alternate path that needs to be deleted is first identified. The traffic on the identified path is then switched to other paths (step 62 ). Topology upgrade objects are created on the source and destination nodes (step 64 ). The object on the source node is set at PENDING_CREATE and the object on the destination node is set at PENDING_UPGRADE. If the circuit is unidirectional then a topology upgrade object is created on working path intermediate nodes between the source and destination nodes (steps 66 and 68 ). The states for the objects on the intermediate nodes are set at PENDING_UPGRADE. Topology upgrade objects are created on each node along the alternate path (step 70 ). The source topology upgrade object state is then changed to PENDING_UPGRADE (step 72 ). A topology upgrade operation is performed on alternate path nodes at step 74 and the connection is destroyed along with the topology upgrade object. If the circuit is unidirectional, a topology upgrade operation is performed on working path intermediate nodes and the connection is changed from two-way to one-way (steps 78 , 80 , and 82 ). A topology upgrade operation is then performed on the source and destination nodes, the path is removed from connection, and the topology upgrade objects are destroyed (steps 84 and 86 ).
FIG. 21 is a flowchart illustrating a process of the present invention for error recovery in an UPSR/SNCP to 2F-BLSR/MSSP conversion. A conversion object which has reference to the circuit id, cross-connect, a list of paths after conversion, old connection type, new connection type, and the state of conversion stage, is created on each node (step 90 ). The shortest paths that the circuit will be converted to are then identified (step 92 ). On the pair of USPR selectors or bridge that forms the two ends of the shortest paths, a conversion object is created with state set to PENDING_CREATE for one and PENDING_UPGRADE for the other (step 94 ). A protection operation is performed to switch traffic onto the shortest paths (step 96 ). Next, going along the longest paths, conversion objects are created on each node in the path with state set to PENDING_UPGRADE (step 98 ). For a unidirectional circuit, the shortest path is also traversed, for any node on the path that either needs to change the connection type from TWOWAY->ONEWAY or UPSR_DC->ONEWAY, a conversion object is created with the state set to PENDING_UPGRADE (steps 100 and 101 ). One of the selectors of the pair that has its state set to PENDING_CREATE is revisited and the state is changed to PENDING_UPGRADE (step 102 ). The connection conversion is then ready to start. Going along the longest paths, each node on the paths requests its conversion object to destroy cross-connect and at the same time destroy itself (step 104 ). Then going along the shortest paths, each node on the paths that has a conversion object created, requests the conversion object to convert the connection type and to destroy itself (step 106 ). Finally, the pair of selectors making the ends of longest/shortest paths requests the conversion objects to convert the connection and destroy itself (step 108 ).
If a failure occurs (e.g., system controller crashes) after step 92 , the controller is simply restarted. If the controller crashes after steps 94 or 96 , the controller is restarted and one of the selectors should be in the state of PENDING_CREATE. The process can be continued from step 96 , if traffic has not been switched to the shortest path completely or from step 98 if switching has been completed. If the controller crashes after step 101 , or in the middle of steps 98 or 101 , the process continues with steps 100 and 102 until the state of PENDING_CREATE is changed to PENDING_UPGRADE, which marks that error recovery preset has been completed. This is possible since, after restart, one of the selectors remains in the PENDING_CREATE state and the system knows that it has not finished creating conversion objects on the affecting nodes. If the controller crashes on steps 102 , 104 , 106 , or 108 , the information can be retrieved and the necessary operations completed (i.e., either destroy connection or modify connection).
The upgrade (conversion) examples described above are preferably performed automatically after receiving user input on the type of upgrade to be performed and identification of the circuits or spans for the upgraded circuit. The system does not require input from the user on modifications for each of the nodes on the circuit. This eliminates the need for manual modification at each node involved in the circuit upgrade and manual checks at each step of the upgrade process. After receiving input from the user, the system automatically performs the upgrade. The automatic upgrade may include pauses to allow confirmation by the user that he wants to continue, or confirmation that no alarms have been raised, for example.
It is desirable to have a GUI and wizard that guide a user through each step and provide a network view of the upgrade. The GUI and wizard provide a network or circuit view of the upgrade so that the user can automatically perform and track the upgrade on the entire circuit rather than having to modify and manually track the upgrade on each individual node. The upgrade may be performed, for example, under control of a CTC, as previously described. For each circuit, the conversion manager system 14 (NMS or user computer) preferably includes circuit information, including for example, circuit name (circuit ID), circuit type (e.g., STS, VT, HOP), circuit size (e.g., STS-1, STS-3, VC4, VT), protection (e.g., unprotected, SNCP), direction (e.g., one-way, two-way), status (e.g., active, discovered), source (source NE of circuit), and destination (destination NE of circuit). The GUI may be configured for example, to display various circuits so that a user can select circuits for the topology conversion.
In one embodiment, the GUI includes a pull down menu that lets the user select the type of conversion or upgrade (e.g., convert UPSR to BLSR or convert unprotected circuit to UPSR). The circuit to be upgraded can then be selected from a list of circuits within the network stored on the user computer. The GUI may also include a window listing routing preferences (e.g., option for reviewing route before upgrade or specifying routing direction). The user can also select whether nodal diversity is required or desired, or request link diversity only. The user is then presented spans to select for the UPSR. After the user selects the spans and instructs the system to perform the upgrade, the conversion is automatically completed.
In another embodiment, the user selects from a pull down menu conversion of SNCP to MS-SPRing or unprotected to SNCP. The user is then presented a window to define the BLSR (MSSPR). For example, the user can specify a 2-fiber or 4-fiber ring, speed (e.g., STM64), ring name (e.g., BLSR1), ring reversion or span reversion. The user is then presented with a graphical overview of the relevant portion of the current network topology and selects the spans for the BLSR (MSSPR). The system then automatically forces traffic to the shortest SNCP paths. If no service affecting alarms are raised, the user can instruct the system to complete the conversion. Traffic may be unprotected for a brief moment during the conversion from UPSR to BLSR, however, this does not significantly affect network traffic.
It is to be understood that the GUI and wizard described herein are only examples, and that different types of wizards or GUIs may be used without departing from the scope of the invention.
FIG. 22 shows a system block diagram of computer system 120 that may be used to execute software of an embodiment of the invention. The computer system 120 includes memory 142 which can be utilized to store and retrieve software programs incorporating computer code that implements aspects of the invention, data for use with the invention, and the like. Exemplary computer readable storage media include CD-ROM, floppy disk, tape, flash memory, system memory, and hard drive. Additionally, a data signal embodied in a carrier wave (e.g., in a network including the Internet) may be the computer readable storage medium. Computer system 120 further includes subsystems such as a central processor 140 , fixed storage 144 (e.g., hard drive), removable storage 146 (e.g., CD-ROM drive), and one or more network interfaces 154 . Other computer systems suitable for use with the invention may include additional or fewer subsystems. For example, computer system 120 may include more than one processor 140 (i.e., a multi-processor system) or a cache memory. The computer system 120 may also include a display, keyboard, and mouse (not shown) for use as a host.
The system bus architecture of computer system 120 is represented by arrows 160 in FIG. 22 . However, these arrows are only illustrative of one possible interconnection scheme serving to link the subsystems. For example, a local bus may be utilized to connect the central processor 140 to the system memory 142 . Computer system 120 shown in FIG. 22 is only one example of a computer system suitable for use with the invention. Other computer architectures having different configurations of subsystems may also be utilized. Communication between computers within the network is made possible with the use of communication protocols, which govern how computers exchange information over a network.
Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations made to the embodiments without departing from the scope of the present invention. Accordingly, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
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A system and method for performing an upgrade in a communication network comprising network elements coupled together to form one or more circuits are disclosed. In one embodiment, the upgrade is generated at a node in communication with the circuits and the method generally comprises providing a list of circuits or spans available for the upgrade and receiving input from a user identifying at least one circuit to be upgraded or at least one span for the upgraded circuit and a type of upgrade to be performed. The method further comprises automatically performing the upgrade.
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CROSS REFERENCE TO RELATED PATENT APPLICATION
The present patent application claims the right of priority under 35 U.S.C. §119 (a)-(d) of German Patent Application No 102005012794.0, filed Mar. 19, 2005.
BACKGROUND OF THE INVENTION
The present invention relates to poly(ether-ester)polyols, processes for their production from monocarboxylic or polycarboxylic acid esters with one or more bound polyether chain(s), and to the production of polyurethanes from these poly(ether-ester)polyols.
Poly(ether-ester)polyols having a block structure are used, for example, in the production of polyurethane materials as phase modifiers in polyol formulations which contain polyester polyols and polyether polyols. Poly(ether-ester)polyols having ester groups distributed evenly along the polymer chains are desirable in PUR applications which require a combination of advantageous polyether properties such as, for example, hydrolysis resistance and low viscosity, on the one hand, and on the other hand, advantageous polyester properties, such as, for example, high abrasion resistance, high tear propagation resistance, high elongation at break and tear strength and good solvent resistance.
Poly(ether-block-esters) having a defined AB two-block or ABA three-block structure cannot be obtained through base-catalysed or acid-catalysed addition of alkylene oxides to OH-functional polyesters, since these polyesters are subject to transesterification and cleavage reactions in the presence of such catalysts. In the production of poly(ether-ester)polyols, one is therefore dependent on prefabricated poly(ether)polyols which in a second step are transesterified or esterified with polyesters or polycarboxylic acids, polycarboxylic acid esters, polycarboxylic acid halides or polycarboxylic acid anhydrides, and low-molecular-weight polyols to form an (AB) n multiblock copolymer. The choice of stoichiometry of the reactants polyether polyol, polycarboxylic acid (derivative) and low-molecular-weight polyol in the esterification or transesterification step determines the average length of the polyester blocks inserted between the polyether blocks. The block structure, the length of the polyester blocks and the functionality of the products are always subject, however, to the statistics prevailing in the production of polycondensates from polyfunctional starting components. The use of double metal cyanide complex catalysis (DMC catalysis) allows polyester polyols to be used as starter components for the production of poly(ester-block-ether)polyols having an AB two-block or ABA three-block structure, and is thus, an improvement on the former processing mode.
WO 01/27185 describes the production of poly(ester-block-ether)polyols starting from polyesters with DMC-catalysed addition of alkylene oxides. According to the process described in WO 03/076488, higher-functional poly(ester-block-ether) polyols are obtained starting from higher-functional polyesters with DMC catalysed addition of alkylene oxides. ABA three-block structures are obtained on the basis of the processing modes described in these two patents, but it is not possible to produce poly(ether-ester)polyols having ester bonds which are distributed homogeneously and evenly along the polymer chains.
According to the teaching of DE 17 70 548 A, poly(ether-esters) are obtained by DMC-catalysed reaction of carboxylic anhydrides with alkylene oxides. The poly(ether-esters) can contain both carboxylic acid and hydroxyl terminal groups. Similarly, U.S. Pat. No. 5,145,883 describes the production of poly(ether-esters) by reacting carboxylic anhydrides and alkylene oxides in the presence of polyether polyols as starter compounds. A disadvantage of the processes described therein, lies in the tendency towards alternating insertion of the comonomers, as a result of which, if excesses of alkylene oxide are used, poly(ether-esters) with block structures are obtained rather than with ester bonds distributed homogeneously and evenly along the polymer chains.
According to WO 95/00574, poly(ester-block-ether) elastomers are obtained by reacting difunctional polyether polyols having a small content of olefinic double bonds (<0.03 meq/g polyether) with polyesters of low-molecular-weight diols and dicarboxylic acids with catalysis using transesterification catalysts. With this method too, poly(ether-ester)polyols with (AB) n multiblock structures are obtained rather than with ester bonds distributed homogeneously and evenly along the polymer chains.
According to U.S. Pat. No. 5,032,671, alkylene oxides and lactones are reacted with DMC catalysis, optionally, using OH-functional starters, to give poly(ether-esters) or poly(ether-ester)polyols. The polymer chains have a block structure or a random distribution of ether and ester bonds. Using the method described in this patent, it is not possible to control the comonomer insertion.
WO 01/04179 and EP 1 112 243A describe the production of esters with one or more bound polyether chain(s) by reacting hydroxyl group-containing esters of carboxylic acids using DMC catalysis. The further reaction of these materials to give poly(ether-esters) with ester bonds distributed homogeneously and evenly along the polymer chains is not disclosed.
The production of poly(ether-esters) having ester bonds distributed homogeneously and evenly along the polymer chains, and highly defined functionalities using DMC catalysis has not previously been described. In addition, the production of poly(ether-esters) is always performed by means of multi-stage processes. The object of the present invention was to provide a process for producing poly(ether-esters), which is characterised by a simple reaction sequence that leads from the starting materials to the product, without complex workup steps and which gives access to structures with ester bonds distributed homogeneously and evenly along the polymer chains, as well as highly defined functionalities.
SUMMARY OF THE INVENTION
It has now been found that monocarboxylic or polycarboxylic acid esters having one or more bound polyether chain(s) can be obtained by reacting hydroxyl group-containing monocarboxylic acid esters and/or polycarboxylic acid esters with alkylene oxides. In preferred embodiments of the invention, one variation includes one or more diols and/or polyols, and, another variation includes, optionally, one or more dicarboxylic acid esters, additionally being present in the above described alkylene oxide addition reaction. The reaction with the alkylene oxides is preferably performed in the presence of double metal cyanide complex catalysts, since the ester groups are then not subject to any disruptive secondary reactions. The desired poly(ether-ester) structures are obtained by subsequent transesterification, optionally, with the addition of a transesterification catalyst, and optionally, with the addition of further diols and/or polyols, and/or further dicarboxylic acid derivatives. The diols and/or polyols, and dicarboxylic acid derivatives which are optionally added, serve to adjust the desired OH value and to adjust the ester group density. Surprisingly, the second stage of poly(ether-ester) polyol synthesis (i.e. the transesterification reaction) can also be performed with no further working up, directly following the alkylene oxide addition. This represents a significant advantage in the management of the process.
If higher-functional polyols (i.e. those having a functionality >2) are added alone, or as a blend with difunctional polyols, either before or during the alkylene oxide addition reaction or before the transesterification reaction, products having a defined functionality are obtained. Such poly(ether-ester) structures are not obtainable via the polycondensation methods of the prior art. Rather, these prior methods lead to a mixture of products of differing functionality, and the maximum functionality that can be achieved is also limited by the process conditions due to crosslinking reactions.
Branched, likewise non-crosslinking, polyfunctional poly(ether-ester) structures can be obtained by alkylene oxide addition to carboxylic acid esters containing several hydroxyl groups, followed by a subsequent transesterification reaction, with the optional addition of diols and/or polyols.
It is equally possible to obtain linear or branched, non-crosslinking, polyfunctional poly(ether-ester) structures having ester terminal groups by alkylene oxide addition to monocarboxylic or polycarboxylic acid esters containing a hydroxyl group, followed by a subsequent transesterification reaction with the addition of monocarboxylic acid esters or polycarboxylic acid esters, which can likewise contain a free hydroxyl group.
A further variation of the present invention comprises the saponification of the monocarboxylic or polycarboxylic acid esters with one bound polyether chain to give the corresponding monocarboxylic or polycarboxylic acids having one bound polyether chain. These can be converted to linear or branched polyfunctional poly(ether-ester) structures having carboxylic acid terminal groups by subsequent esterification with optionally added monocarboxylic or polycarboxylic acids, which may also contain a free hydroxyl group.
Thus, the present invention provides a process for producing poly(ether-esters). This process comprises:
(1) reacting
a) one or more monocarboxylic or polycarboxylic acid esters containing one or more hydroxyl groups and having the general formula:
wherein:
R represents a monovalent aryl, alkyl, aralkyl, alkenyl or alkynyl radical, R′ represents an at least divalent aryl, alkyl, aralkyl, alkenyl or alkynyl radical, in which:
m=1 and n=1, m≧2 and n=1, or n≧2 and m=1,
with
b) one or more alkylene oxides, with ring opening to give the corresponding monocarboxylic acid esters or polycarboxylic acid esters having one or more bound polyether chains, in which the alkylene oxide addition is optionally performed in the presence of:
c) one or more diols and/or polyols, and, optionally,
d) one or more dicarboxylic acid esters; and then, further:
(2) reacting the products produced in step (1) by one of the following:
(i) transesterifying the products from (1) to yield hydroxyl-functional poly(ether-esters), in which the transesterification is optionally performed with addition of:
(a) one or more diols and/or polyols, or, optionally, (b) one or more diols, and dicarboxylic acids or dicarboxylic acid derivatives, or, optionally, (c) one or more diols or polyols, and monocarboxylic acid esters or monocarboxylic acids containing one or more hydroxyl groups,
(ii) transesterification of the products from (1) with
(a) additional monocarboxylic acid esters and/or polycarboxylic acid esters, which can contain a free hydroxyl group, to yield poly(ether-esters) having ester terminal groups,
or (iii) saponification (i.e. hydrolysis) of the products from (1) to yield the corresponding monocarboxylic acids or polycarboxylic acids with a bound poly(ether) chain, and esterification of these acids with optionally added monocarboxylic acids and/or polycarboxylic acids, which can contain a free hydroxyl group, to yield poly(ether-esters) having carboxylic acid terminal groups.
DETAILED DESCRIPTION OF THE INVENTION
Suitable compounds to be used as starting components for the production of monocarboxylic or polycarboxylic acid esters with bound polyether chains for component a) in reaction step (1) include aromatic hydroxyl group-containing monocarboxylic acid esters or polycarboxylic acid esters such as, for example, the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl esters of the various isomers of hydroxybenzoic acid, the esters of the various isomers of hydroxymethylbenzoic acid, the esters of the various isomers of dihydroxybenzoic acid, the esters of trihydroxybenzoic acid, the esters of hydroxyphenylacetic acid, the esters of hydroxyphthalic acid and the esters of hydroxynaphthoic acid.
Suitable aliphatic hydroxyl group-containing monocarboxylic acid esters or polycarboxylic acid esters include, for example, the esters of glycolic acid, mandelic acid, lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 3-hydroxypropionic acid, tropic acid, ricinoleic acid, glyceric acid, hydroxymalonic acid, malic acid and citric acid. Lactones can also be used, but they must first be converted into the corresponding open-chain hydroxyl group-containing carboxylic acid esters by reaction with an alcohol. The individual monocarboxylic acid esters containing one or more hydroxyl groups or the individual polycarboxylic acid esters containing one hydroxyl group can also be used in a blend.
Suitable diols or polyols which are optionally added in reaction step (1) as component c) preferably have functionalities of 2 to 8. Examples of suitable diols and polyols include compounds such as propylene glycol, ethylene glycol, diethylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, hexanediol, pentanediol, 3-methyl-1,5-pentanediol, 1,12-dodecanediol, glycerol, trimethylol propane, triethanolamine, pentaerythritol, sorbitol, sucrose, hydroquinone, catechol, resorcinol, bisphenol F, bisphenol A, 1,3,5-trihydroxybenzene, condensates of formaldehyde and phenol or melamine or urea containing methylol groups, and Mannich bases. Alkylene oxide addition products of the previously mentioned diols or polyols (i.e. polyether polyols) having OH values of 6 to 800 mg KOH/g can also be used.
In addition to the aforementioned diols, polyols or corresponding poly(ether) polyols, dicarboxylic acid esters, i.e. component d), can also optionally be added in reaction step (1). With the addition of dicarboxylic acid esters, in addition to the previously mentioned adjustment of the desired ester group density and OH value, the density of the OH groups at the start of the alkylene oxide addition reaction can also be reduced extremely easily, which in the case of DMC catalysis, in particular, offers a processing advantage. The esters of the following acids are cited here by way of example as suitable dicarboxylic acid esters: succinic acid, glutaric acid, adipic acid, phthalic, isophthalic or terephthalic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, and mixtures thereof.
Suitable alkylene oxides to be used as component b) in reaction step (1) include, for example, ethylene oxide, propylene oxide, 1,2-butylene oxide or 2,3-butylene oxide and styrene oxide. Propylene oxide and ethylene oxide, either individually or as mixtures, are preferably used. The polyaddition reaction can be catalysed both by Lewis acids such as BF 3 O(Et) 2 or B(C 6 F 5 ) 3 and by bases such as alkaline or alkaline-earth metal hydroxides, and by double metal cyanide complex catalysts. The reaction in step (1) is preferably performed using DMC catalysts.
The DMC catalysts which are particularly suitable for the process according to the invention are known in principle. DMC catalysts have found commercial interest primarily for the production of polyether polyols by polyaddition of alkylene oxides to starter compounds displaying active hydrogen atoms (see for example, U.S. Pat. Nos. 3,404,109, 3,829,505, 3,941,849 and 5,158,922, the disclosures of which are hereby incorporated by reference). The use of DMC catalysts leads to a reduction in the content of monofunctional polyethers having terminal double bonds, i.e. the so-called monools, in comparison to the conventional production of polyether polyols using alkaline catalysts. Improved, highly active DMC catalysts, which are described for example in U.S. Pat. Nos. 5,470,813, 5,482,908 and 5,536,883 (believed to correspond to EP-A 700 949), U.S. Pat. Nos.5,712,216 and 6,018,017 (believed to correspond to EP-A 743 093), U.S. Pat. Nos. 5,545,601 and 5,637,673 (believed to correspond to EP-A 761 708), U.S. Pat. Nos. 5,627,120 and 5,789,626 (believed to correspond to WO 97/40086), U.S. Pat. No. 5,714,428 (believed to correspond to WO 98/16310) and U.S. Pat. No. 6,585,566 (believed to correspond to WO 00/47649), the disclosures of which are hereby incorporated by reference, additionally have an unusually high activity and allow polyether polyol production with very low catalyst concentrations (e.g. 25 ppm or less), such that the catalyst no longer has to be separated out of the final product. The highly active DMC catalysts described in, for example, U.S. Pat. Nos. 5,482,908 and 5,536,883 (believed to correspond to EP-A 700 949), which in addition to a double metal cyanide compound (e.g. zinc hexacyanocobaltate(III)) and an organic complex ligand (e.g. tert-butanol,) also contain a polyether with a number-average molecular weight greater than 500 g/mol, are a typical example.
The addition of alkylene oxides to starting mixtures containing one or more monocarboxylic and/or polycarboxylic acid esters which contain one or more hydroxyl groups can be continued until an OH value is reached that is as low as is desired. The OH value range from 5 to 420 is preferred. The various alkylene oxides can also be added blockwise instead of as a mixture. In such cases, monocarboxylic or polycarboxylic acid esters are obtained wherein the bound polyether chain(s) display block structures. Pure ethylene oxide or mixtures of propylene oxide and ethylene oxide with a high ethylene oxide content are preferably added as the terminal block so that the polyether chains bound to the monocarboxylic or polycarboxylic acid esters contain from about 40 to 100% primary OH terminal groups.
The hydroxyl group-containing (poly)carboxylic acid esters used in accordance with the present invention as starter components a), the optionally added diols or polyols, i.e. component c), and the optionally added dicarboxylic acid esters, i.e. component d), can be placed in the reactor in advance, or supplied to the reactor continuously during the reaction together with the alkylene oxide. In the latter processing mode, a small amount of an addition product comprising starter and alkylene oxide is conventionally placed in the reactor in advance. It is also possible that this addition product is the product that it to be produced by the process. It is equally possible to remove the reaction product continuously from the reactor, in which case catalyst must also be continuously supplied to the reactor, in addition to alkylene oxide and starter. The various processing variants for the production of polyethers by the alkylene oxide addition method with DMC catalysis are described in the previously mentioned documents, and are also disclosed in, for example, U.S. Pat. Nos. 5,777,177 and 5,919,988 (believed to correspond to WO 97/29146) and in U.S. Pat. No. 5,689,012 (believed to correspond to WO 98/03571), the disclosures of which are hereby incorporated by references.
The DMC-catalysed polyaddition of alkylene oxides is generally performed at temperatures of 20 to 200° C., preferably 40 to 180° C., and more preferably at temperatures of 50 to 150° C. The reaction can be performed at overall pressures of 0.0001 to 20 bar. The polyaddition reaction can be performed in bulk, or in an inert organic solvent such as toluene and/or THF. The amount of solvent is typically from about 10 to about 30 wt. %, based on the total amount of alkylene oxide addition product to be produced.
The catalyst concentration is chosen such that under the specified reaction conditions, good control of the polyaddition reaction is possible. The catalyst concentration is generally 0.0005 wt. % to 1 wt. %, preferably 0.001 wt. % to 0.1 wt. %, and more preferably 0.001 to 0.03 wt. %, based on the total amount of alkylene oxide addition product to be produced. Small amounts (i.e. 1 to 500 ppm, relative to the amount of starter) of organic or inorganic acids, as described in U.S. Pat. No. 6,077,978 (believed to correspond to WO 99/14258), the disclosure of which is hereby incorporated by reference, can be added to the hydroxyl group-containing (poly)carboxylic acid esters used according to the invention as starter components, and the optionally added diols and/or polyols, and the optionally added dicarboxylic acid esters.
Age resistors such as, for example, antioxidants can also optionally be added to the alkylene oxide addition products obtained according to step (1).
In one embodiment of the process according to the invention, the products obtained in step (1) are reacted under transesterification conditions, optionally with addition of further diols or polyols, to give OH-functionalised poly(ether-esters), i.e. step (2(i)). The optionally added diols and/or polyols, component (i)(a), preferably display functionalities of 2 to 8. Suitable compounds include, by way of example, propylene glycol, ethylene glycol, diethylene glycol, 1,2-, 1,3-, 1,4-butanediol, hexanediol, pentanediol, 3-methyl-1,5-pentanediol, 1,12-dodecanediol, glycerol, trimethylol propane, triethanolamine, pentaerythritol, sorbitol, sucrose, hydroquinone, catechol, resorcinol, bisphenol F, bisphenol A, 1,3,5-trihydroxybenzene, condensates of formaldehyde and phenol or melamine or urea containing methylol groups, and Mannich bases. Alkylene oxide addition products of the previously mentioned diols or polyols (i.e. polyether polyols) having OH values of 6 to 800 mg KOH/g can also added at this point. The person skilled in the art is easily able to calculate the amount of these diols and/or polyols, i.e. component (i)(a) of this step, which are optionally to be added from the desired OH value of the poly(ether-ester) to be produced.
In order to produce the OH-functionalised poly(ether-esters), the previously mentioned starting materials can be polycondensed catalyst-free or in the presence of transesterification catalysts, conveniently in an atmosphere of inert gases, such as, for example, nitrogen, helium or argon, and also in the melt at temperatures of 150 to 300° C., preferably 180 to 230° C., until the desired OH value of the resultant product is achieved.
In a preferred variation, transesterification is performed at a pressure of less than 500 mbar, preferably 1 to 150 mbar. The pressure can be adjusted to the reaction progress during the reaction to suppress the removal of highly volatile starting components in the initial stage of polycondensation. All known transesterification catalysts such as mineral acids, Lewis acids and bases can be used to accelerate the transesterification reaction. Iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium and tin catalysts in the form of metals, metal oxides or metal salts, e.g. metal alkoxides, are also considered suitable. Reference is also made, in this connection, to improved transition metal catalysts which have recently become known and which are less sensitive to hydrolysis. Catalysts such as these are described in, for example, U.S. Pat. No. 6,541,411 (believed to correspond to DE-A 100 59 612), the disclosure of which is hereby incorporated by reference.
If products with a higher branching point density or a higher density of ester groups are desired, it is naturally possible to also incorporate low-molecular-weight monocarboxylic acid esters or low-molecular weight monocarboxylic acids with one or more bound hydroxyl groups, i.e. component (i)(c), in the transesterification reaction. Examples of such compounds are aromatic and aliphatic hydroxyl group-containing carboxylic acids or esters thereof, such as, for example, the various isomers of hydroxybenzoic acid, the various isomers of hydroxymethylbenzoic acid, the various isomers of dihydroxybenzoic acid, trihydroxybenzoic acid, hydroxynaphthoic acid, glycolic acid, mandelic acid, lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 3-hydroxypropionic acid, tropic acid, ricinoleic acid and glyceric acid. Lactones can likewise be used.
If monocarboxylic acid esters obtained according to step (1) with a bound polyether chain are further reacted in step (2), then the transesterification reaction can also include, dicarboxylic acids or their esters, i.e. component (i)(b), in addition to diols, to produce a higher density of ester groups. The following compounds are mentioned here by way of example: succinic acid, glutaric acid, adipic acid, phthalic, isophthalic or terephthalic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid and mixtures thereof, as well as mixtures which predominantly contain the mentioned acids or their esters.
Age resistors such as, for example, antioxidants can optionally be added to the OH-functionalised poly(ether-esters) obtained.
In another embodiment of the process according to the invention, the products produced in step (1) are reacted with additional (ii)(a) monocarboxylic and/or polycarboxylic acid esters, which can likewise contain a free hydroxyl group, under transesterification conditions to yield poly(ether-ester) structures having ester terminal groups, i.e. step (2)(ii). The added dicarboxylic or polycarboxylic acid esters preferably display functionalities of 2 to 3. Examples of compounds which are suitable herein include, for example, the diesters of succinic acid, glutaric acid, adipic acid, phthalic, isophthalic or terephthalic acid, suberic acid, azelaic acid, sebacic acid, maleic acid and fumaric acid. Suitable triesters are for example the esters of trimesic acid, trimellitic acid and tricarballylic acid. Suitable carboxylic acid esters having a free hydroxyl group are for example the methyl, ethyl, n-propyl, n-butyl esters of the various isomers of hydroxybenzoic acid, the esters of the various isomers of hydroxymethylbenzoic acid, the esters of glycolic acid, mandelic acid, lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 3-hydroxypropionic acid, tropic acid, ricinoleic acid, hydroxymalonic acid, malic acid and citric acid. The reaction conditions here correspond to those described above for the transesterification process. Age resistors such as, for example, antioxidants can optionally be added to the poly(ether-esters) obtained in this way having ester terminal groups.
In a further embodiment of the process according to the invention, the products produced in step (1) are further reacted in a second step, i.e. step (2)(iii), by hydrolysing with water, to yield the corresponding monocarboxylic or polycarboxylic acids containing a bound polyether chain. This reaction can be catalysed with acids or bases. Corresponding processing modes are known to the person skilled in the art. The monocarboxylic or polycarboxylic acids thus obtained containing a bound polyether chain, can be further reacted by esterification reactions, optionally, after addition of further dicarboxylic or polycarboxylic acids which may also contain a hydroxyl group, i.e. component (iii)(a), to form linear, star-shaped or branched poly(ether-ester) structures having carboxylic acid terminal groups. Suitable dicarboxylic or polycarboxylic acids include, for example, succinic acid, glutaric acid, adipic acid, phthalic, isophthalic or terephthalic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, trimesic acid, trimellitic acid, tricarballylic acid and pyromellitic acid. Cyclic anhydrides of the mentioned acids can also be used. Suitable carboxylic acids having a free hydroxyl group include, for example, the various isomers of hydroxybenzoic acid, the various isomers of hydroxymethylbenzoic acid, glycolic acid, mandelic acid, lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, tropic acid, ricinoleic acid, hydroxymalonic acid, malic acid and citric acid.
In order to produce the carboxylic acid-functionalised poly(ether-esters), the above mentioned starting materials can be polycondensed catalyst-free or in the presence of esterification catalysts, conveniently in an atmosphere of inert gases. Suitable inert gases include, for example, nitrogen, helium or argon. The above mentioned starting materials can also be polycondensed in the melt at temperatures of 150 to 300° C., preferably 180 to 230° C., and optionally, until the desired acid value is achieved.
In a preferred variation, esterification is performed under a pressure of less than 500 mbar, preferably 1 to 150 mbar. The pressure can be adjusted to the reaction progress during the reaction to suppress the removal of highly volatile starting components in the initial stage of polycondensation. In addition to mineral acids, iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium and tin catalysts in the form of metals, metal oxides or metal salts can be used as esterification catalysts. In the polycondensation process, diluents and/or entrainers, such as, for example, benzene, toluene, xylene or chlorobenzene can be added to the reaction mixture for the azeotropic removal of the condensation water by distillation.
Age resistors such as, for example, antioxidants can optionally be added to the poly(ether-esters) thus obtained having carboxylic acid terminal groups.
The poly(ether-esters) produced according to steps (1) and (2)(i) having hydroxyl terminal groups can be used as starting components for the production of solid or foamed polyurethane materials and of polyurethane elastomers.
To this end the poly(ether-esters) having hydroxyl terminal groups are optionally mixed with additional isocyanate-reactive components, and reacted with organic polyisocyanates, optionally, in the presence of blowing agents, and in the presence of catalysts, and, optionally, in the presence of other additives such as cell stabilisers. Such reactions result in the production of polyurethanes.
The polyurethane materials can be produced by the methods described in the literature, e.g. the one-shot or prepolymer method, using mixing devices known in principle to the person skilled in the art.
EXAMPLES
Starting Materials:
The following components were used in the working examples:
Polyol A: a difunctional polyether with an OH value of 260, and produced by adding propylene oxide to propylene glycol Polyol B: a trifunctional polyether with an OH value of 238, produced by adding propylene oxide to glycerol DMC catalyst: a double metal cyanide catalyst, containing zinc hexacyano-cobaltate, tert-butanol and polypropylene glycol, with a number-average molecular weight of 1000 g/mol; prepared as described in U.S. Pat. Nos. 5,482,908 and 5,536,883, the disclosures of which are herein incorporated by reference, and which are believed to correspond to EP-A 700 949
Example 1
Production of a Monocarboxylic Acid Ester with a Bound Polypropylene Oxide Chain:
0.105 g of DMC catalyst were added to 333.1 g of p-hydroxybenzoic acid ethyl ester in a 2 1 pressurised autoclave. The ambient oxygen was removed by repeated evacuation and gassing with nitrogen. The reactor pressure at the start of the addition of propylene oxide was 0.1 bar, the agitator speed was set to 800 rpm, and the reaction temperature was 130° C. A total of 682 g of propylene oxide were added as follows. First, 132 g of propylene oxide were added over a period of 2 h in 3 equal portions. After adding a further 20 g of propylene oxide the reaction started, as indicated by a sudden fall in pressure in the reactor. The remaining propylene oxide was able to be added within 2 hours. On completion of the addition of propylene oxide, the reaction was allowed to continue until the pressure in the reactor assumed a constant value of 0.8 bar. The product was then heated for 30 minutes at 90° C. and 20 mbar, and reacted further with no further workup.
OH value of resultant product: 105.5 mg KOH/g
Viscosity of resultant product at 25° C.: 225 mPas
Example 2
Production of a Difunctional Poly(ether-ester):
247 g of Polyol A were added to 989 g of the product from Example 1. After the addition of 100 mg of titanic acid tetrabutyl ester, the mixture was heated to 200° C., first under nitrogen, then under vacuum (1 mbar) with stirring. After 85 g of ethanol had been distilled off, the reaction was terminated.
OH value of the resultant product: 57.6 mg KOH/g
Viscosity of the resultant product: 9360 mpas at 25° C.
Example 3
Propoxylation of a Mixture Comprising a Trifunctional Polyol and 4-hydroxybenzoic Acid Ethyl Ester and Transesterification to Give the Trifunctional Polyether-ester:
0.3 g of DMC catalyst were added to 840.4 g of Polyol B and 592.4 g of 4-hydroxybenzoic acid ethyl ester in a 10 1 pressurised autoclave. The reactor contents were heated for 53 minutes at 80° C. in vacuo whilst being stirred (800 rpm). At the start of the addition of propylene oxide, the reactor pressure was 0.2 bar, the agitator speed for the reaction was kept at 800 rpm, and the reaction temperature was 130° C. A total of 567.23 g of propylene oxide were added at a constant rate over a period of 2.67 h. After 189 g of propylene oxide was added, the reaction start was indicated by a sudden drop in pressure in the reactor (maximum pressure reached: 1.35 bar). On completion of the addition of propylene oxide, the reaction was allowed to continue at 130° C. until a constant pressure of 0.4 bar was reached. After cooling to 90° C., the reactor contents were heated for 30 minutes at 20 mbar. The autoclave was then brought to normal pressure by pressurising with nitrogen and the contents were cooled to 50° C. A sample of the propoxylate was taken in order to determine the OH value and viscosity.
OH value of resultant product: 196.15 mg KOH/g
Viscosity of resultant product at 25° C.: 301 mPas
To this product, 197.7 mg of titanic acid tetrabutyl ester were added. The mixture was heated to 200° C., first under normal pressure, then under vacuum (1 mbar). After 160 g of ethanol had been distilled off, the reaction was terminated.
OH value of resultant product: 106.7 mg KOH/g
Viscosity of resultant product at 25° C.: 20,900 mPas
Example 4
Propoxylation/Ethoxylation of a Mixture Comprising a Trifunctional Polyol and 4-hydroxybenzoic Acid Ethyl Ester and Transesterification to give the Trifunctional Polyether-ester:
313 mg of DMC catalyst were added to 568.2 g of polyol B, 400.5 g of 4-hydroxybenzoic acid ethyl ester and 275 mg of 85% phosphoric acid in a 10 1 pressurised autoclave. The reactor contents were heated for 5 h at 80° C. in vacuo with stirring (at 800 rpm). The pressure was increased to 1.5 bar by the addition of nitrogen, and 206.55 g of propylene oxide were added at 140° C. within 1.43 h while stirring (at 800 rpm). After 130 g of propylene oxide was added, the reaction start was indicated by a sudden fall in pressure in the reactor (maximum pressure reached: 3.2 bar). Directly following the addition of propylene oxide, 826.4 g of ethylene oxide were added at 140° C. over a period of 2.13 h while stirring (at 800 rpm). The reaction was allowed to continue at 140° C. until a constant final pressure of 1.9 bar was reached. After cooling to 90° C., the reactor contents were heated for 30 minutes at 20 mbar. The autoclave was then brought to normal pressure by pressurising with nitrogen and the contents cooled to 50° C. A sample of the alkylene oxide addition product was taken in order to determine the OH value and viscosity.
OH value of the resultant product: 134.4
Viscosity of the resultant product at 25° C.: 491 mPas
Content of primary OH groups in the product: 77%
Then, 183.1 mg of titanic acid tetrabutyl ester were added and the mixture was heated to 200° C., first under normal pressure, then under vacuum (1 mbar). After 107.7 g of ethanol had been distilled off, the reaction was terminated.
OH value of the resultant product: 73.0 mg KOH/g
Viscosity of the resultant product at 50° C.: 679 mPas
Content of primary OH groups in this product: 74%
Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
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The invention is directed to novel poly(ether-ester)polyols, processes for their production from monocarboxylic or polycarboxylic acid esters with one or more bound polyether chain(s). This invention also relates to the production of polyurethane materials in which the isocyanate-reactive component comprises these poly(ether-ester)polyols.
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FIELD OF INVENTION
This invention pertains to the field of calculating disparity between two sets of data. More specifically, this invention pertains to calculating disparity in two sets of data using variably sized windows.
BACKGROUND OF THE INVENTION
There are many fields in which measurements of disparity are useful. For two similar data sets, disparity is a measure of the difference in location, within each data set, of a subset of data which appears, either identically or similarly, in both data sets. Location, for purposes of disparity measurement, is based on one or more independent variables by which the data are ordered. For example, consider two images with the pixel values in each image being data ordered by horizontal and vertical location. If a sub-image of an apple appears in both images, but at different locations in each, the disparity associated with the sub-image of the apple is the difference between these locations. If the subimage appears in the second image five pixels to the right of the location of the sub-image in the first image, the disparity is five pixels to the right. Given similar data sets, a disparity map can be constructed which specifies where each region of a first data set appears in a second data set, relative to the location of the region in the first data set.
One field in which disparity measurements are used is stereoscopic image interpretation. In stereoscopic imaging, two or more images of a scene are created. The stereoscopic images represent substantially the same scene at the same time, but they represent the scene from different vantage points. Often, these different views are nearly parallel, and the separation of the vantage points is in a direction substantially perpendicular to the direction of the views. The direction of the separation of the vantage points is referred to as the epipolar direction. Each image in a stereoscopic set of images typically contains representations of many of the same objects as the other image. Although the objects are viewed from slightly different perspectives, the representation of each object is generally similar in both images. Due to the effect of parallax, the position of each object is usually different in each image. Objects of shallow depth (near the vantage points) exhibit more disparity between images than objects of greater depth (farther from the vantage points). This disparity is in the epipolar direction. By measuring the disparity associated with objects in stereoscopic images, the depth of those objects can be determined. By measuring the disparity associated with small regions in a stereoscopic set of images, a depth map for the represented scene can be determined. Three dimensional information is retrieved from the disparity in a set of two dimensional stereoscopic images.
Another application for disparity analysis involves a series of images representing substantially the same scene at distinct points in time. Such a series of images can, for example, constitute a motion picture sequence. When compressing such a series of images it is useful to determine disparity information for the images. The disparity information can be used with a key image to reconstruct the other images of the series, by appropriately moving portions of the key image as indicated by the disparity information.
Disparity information is also useful in determining velocity information for objects represented in a series of time differentiated images. Particle image velocimetry and laser speckle velocimetry utilize disparity information from time differentiated images to determine velocities within a field of view. A related field, laser speckle metrology, uses disparity information from two images of a specimen to determine, among other things, changes in the deformation of the specimen between the times corresponding to the two images.
Other applications of disparity analysis exist in non-image related fields. For example, disparity analysis can be used in audio analysis to determine the temporal disparity of sounds in acoustical signals. Temporal disparity can also be used with acoustical signals in seismic research to determine, through triangulation, the location of seismic events. Disparity analysis also has applications in the field of electronic signal analysis.
There are several methods for determining disparity information from sets of data. Generally, interrogation regions of a predetermined size are selected from a reference data set, and candidate regions in a target data set are compared to the interrogation region. The candidate region which is most similar to the interrogation region is identified as a matching region. The location of the matching region within the target data set, relative to the location of the interrogation region within the reference data set, specifies the disparity for the interrogation region. Conventional correlation techniques are generally used for determining the similarity of a candidate region and an interrogation region.
Using conventional methods, it is often difficult to predetermine the correct size for interrogation regions. Small interrogation regions tend to result in more incorrect matches than larger interrogation regions. Large interrogation regions, however, lack locality in that they determine disparity for a larger subset of data. The use of larger interrogation regions results in lower resolution disparity maps.
What is needed is a system and method for achieving high accuracy in disparity determination without unnecessarily sacrificing resolution.
SUMMARY OF THE INVENTION
In one embodiment, the present invention is a computer-implemented method for determining disparity in two sets of data. In an exemplary embodiment, the two sets of data comprise a stereoscopic set of images (110). The size of interrogation regions (302) used for disparity analysis is varied dynamically. An initial interrogation region (302) from a reference stereoscopic image (110a) is compared to several candidate regions (304) from a target stereoscopic image (110b). If none of the comparisons indicate a required level of similarity, the process is repeated with a larger interrogation region (302). The process of successively using larger interrogation regions (302) continues until either a maximum interrogation region (302) size is reached, or the required level of similarity is indicated in one of the comparisons.
For those parts of an image set which can be accurately matched using small interrogation regions (302), small interrogation regions (302) are used, maintaining spatial resolution. For those parts of the image set which cannot be accurately matched using small interrogation regions (302), larger interrogation regions (302) are used, maintaining the desired level of accuracy. For each part of the image set, the desired level of accuracy is maintained without unnecessarily sacrificing spatial resolution.
In other embodiments, the invention comprises an apparatus and a computer-readable medium containing a program for using these methods to determine the disparity in two sets of data.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration of a set of stereoscopic images 110a and 110b, and the scene represented by the images 110.
FIGS. 2a and 2b are flowcharts illustrating the operation of an exemplary embodiment.
FIG. 3 is an illustration of interrogation region 302 in reference image 110a and candidate regions 304 in target image 110b.
FIG. 4 is an illustration of a typical similarity profile when a small interrogation region 302 is used.
FIG. 5 is an illustration of a typical similarity profile when a large interrogation region 302 is used.
FIG. 6 is an illustration of one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An exemplary embodiment of the present invention involves the extraction of depth information from a stereoscopic set of images.
Referring now to FIG. 1, a set of cameras 100a, 100b simultaneously captures images 110a, 110b of a scene from slightly different vantage points. The dashed lines indicate the field of view of each camera 100. Objects 102, 104 in the scene appear in images 110 captured by cameras 100. Object 104 is represented in images 110 by sub-images 104' which exhibit greater epipolar disparity than sub-images 102' which represent object 102. This is due to the effect of parallax, and it indicates that object 104 is nearer to cameras 100 than is object 102. The depth of objects 102, 104 in the scene is calculated from Equation 1: ##EQU1## where Depth object is the depth of an object, Depth image is the distance from the image planes of cameras 100 to the camera vantage points, Offset vantage is the distance between the vantage points of cameras 100a and 100b, and Disparity object is the disparity associated with the sub-images of the object.
Measurements of disparity in the set of images 110 are used to generate depth information for the scene. In an exemplary embodiment of the present invention, image 110a is declared a reference image, and image 110b is declared a target image. Interrogation regions are selected in reference image 110a, and one disparity value is calculated for each, using the information in target image 110b. The interrogation regions are each centered on an interrogation point of reference image 110a, the interrogation points covering reference image 110a with a fixed distance between interrogation points. In one embodiment, each interrogation point is displaced from adjacent interrogation points by one pixel. In other embodiments, the interrogation points are spaced further apart. It is not necessary for the interrogation points to be arranged in a regular manner, and in alternate embodiments the interrogation points can be arranged in any manner.
FIGS. 2a, 2b, and 3 illustrate the operation of the exemplary embodiment of the present invention. A location variable is set 202 to the first interrogation point in reference image 110a. A size variable which indicates the size of interrogation region 302 is set 204 to a minimum value, and a threshold variable which indicates a similarity threshold is set 204 to a maximum value. Then interrogation region 302 of reference image 110a is determined 206 such that it is the size specified by the size variable, and it is centered at the interrogation point specified by the location variable.
A first candidate region 304a of target image 110b is selected 208. In the exemplary embodiment, all candidate regions 304 are the same size as interrogation regions 302. In other embodiments, however, candidate regions 304 can be different sizes than interrogation region 302.
Next, the similarity between interrogation region 302 and candidate region 304 is determined 210. There are many correlation methods for determining the similarity of two image regions. In some correlation methods, each region is filtered so that only the high frequency portion of each image is used for comparison. High-pass filtered versions of each region can be created by subtracting from each region the average pixel value of that region. Other correlation methods operate on data which have not been high-pass filtered.
If images 110 are full color images, the comparison can be performed independently for each color component. Where separate comparisons are performed for each color component, the similarity value for candidate region 304 can be a combination of the similarity values for each of the component colors. In the exemplary embodiment, the similarity value for candidate region 304 is the least of the component color similarity values.
One correlation method which can be used for calculating a similarity value is the normalized correlation method described by Equation 2: ##EQU2## where S is the similarity value to be calculated, I i is the value of pixel i of interrogation region 302, C i is the value of pixel i of candidate region 304, and N is the number of pixels in a region. This same correlation method can be used in embodiments of the invention other than those which pertain to images. In the general case, N is the number of data points available in regions 302, 304, I i corresponds to each data point in interrogation region 302, and C i corresponds to each data point in candidate region 304.
The normalized correlation calculation shown in Equation 2, while useful, is computationally expensive. A simpler correlation calculation can be implemented using the normalized absolute value difference method of Equation 3: ##EQU3## where P max is the largest possible pixel value. In the exemplary embodiment, this method is used with P max being 255. Similarity value S varies from 0 to 1, with 0 representing absolute dissimilarity and 1 representing identity between candidate region 304 and interrogation region 302. Many other correlation methods will be apparent to those skilled in the art, including variations which do not normalize the similarity values to a scale from 0 to 1.
After the similarity value is calculated for candidate region 304, it is recorded 210. Then a test is performed 212 to determine whether the current candidate region 304 is the last to be tested. If it is not the last candidate region 304, the next candidate region 304 is selected 214, and the next similarity value is calculated and recorded 210. In selecting candidate regions 304 to be examined, different methods can be used. For stereoscopic images, disparity is expected only in the epipolar direction. In the exemplary embodiment the epipolar direction is horizontal. Also, since parallax requires that objects 102', 104' in image 110b, appear only to the left of the same objects 102', 104' in image 110a, candidate regions 304 are examined only if they would correspond to disparities to the left. In FIG. 3, candidate regions 304a, 304b, and 304c are examined, since all are centered on the same horizontal line as interrogation region 302, and all are to the left, relative to target image 110b, of interrogation region 302, relative to reference image 100a. For clarity, in FIG. 3, candidate regions 304 are not shown as overlapping. In actual practice, candidate regions 304 will often overlap. In the exemplary embodiment, each successive candidate region 304 is displaced from the previous candidate region 304 by only one pixel.
After all candidate regions 304 have been examined, and all similarity values for those candidate regions 304 have been recorded, the similarity values are compared 216 to the threshold variable. If no similarity value exceeds 218 the similarity threshold, then none of the candidate regions 304 are similar enough to interrogation region 302 to constitute a matching region. In that case the size variable is compared 220 to a maximum size and the threshold variable is compared 220 to a minimum value. If the size variable is below the maximum and the threshold variable is above the minimum, then the threshold is lowered 222 and the size is increased 222. A new interrogation region 302 is then reselected 206 at the same location, with the new, larger size.
FIG. 4 illustrates a typical variation of similarity values for candidate regions 304 when a small interrogation region 302 is used. With a small number of sample points (pixels) in the regions 302, 304 to compare, background noise tends to mask the peak which should indicate the location of the matching region. FIG. 5 illustrates a typical variation of similarity values for candidate regions 304 where a larger interrogation region 302 is used. The peak which indicates the location of the matching region is clearly distinguishable over the background noise. Because smaller interrogation regions 302 are more likely to result in incorrect matches, due to spurious peaks in similarity, a higher threshold of similarity is generally useful for smaller interrogation regions 302. As the size of interrogation region 302 increases, and the chance of mismatch lessens, the threshold for similarity is lowered in the exemplary embodiment. In alternate embodiments, the similarity threshold can remain fixed for all interrogation regions 302. For some correlation methods it might be necessary to scale the similarity threshold with interrogation region 302 size, resulting in higher thresholds for larger sizes. Such variations are contemplated within the present invention. In the exemplary embodiment, for images which are 1000 pixels by 1000 pixels in size, interrogation regions 302 are initially 8 pixels by 8 pixels. If the similarity peak does not exceed 0.8, the interrogation region 302 size is increased to 32 pixels by 32 pixels. Then, if the peak similarity value does not exceed 0.7, the interrogation region 302 size is increased to 48 pixels by 48 pixels. Finally, if the peak similarity value does not exceed 0.4, an interrogation region 302 size of 96 pixels by 96 pixels is used with a new threshold of zero. Those skilled in the art will recognize that different combinations of interrogation region 302 size and threshold value will be appropriate in different circumstances.
The use of a threshold for similarity evaluation is simple and can be implemented for relatively fast performance. Other methods, however, yield a more accurate similarity determination in some circumstances. One such method is to calculate the mean and standard deviation for the set of similarity values corresponding to the candidate regions. For the candidate region corresponding to the peak value, a ratio is calculated. The numerator of the ratio is the peak similarity value minus the mean similarity value, and the denominator is the standard deviation of the similarity values. The ratio indicates how unique the peak value is in the set of similarity values, in terms of standard deviations from the mean. A ratio near zero indicates that the peak value is not particularly differentiated from the other similarity values, while a ratio near four will indicate that the peak value stands out significantly from the background. A threshold can then be applied to this ratio, resulting in a more accurate determination for some sets of data.
One advantage to using a correlation method such as that described in Equation 3, rather than the kind of method described in Equation 2, is that the results of each similarity calculation can be reused in the event that a larger interrogation region 302 size must be examined. By undoing the normalization performed in Equation 3, the summation of the absolute values of pixel differences is easily obtained. Because the pixels for which the calculation was performed are part of the larger regions 302, 304, it is not necessary to repeat this summation when applying Equation 3 to the larger regions 302, 304. Using Equation 3, the similarity value can be calculated progressively, continuing with the new pixels each time larger regions 302, 304 are needed. Using a calculation method such as that presented in Equation 2 requires starting the calculation anew each time regions 302, 304 are enlarged.
Returning to the exemplary embodiment detailed in the flowchart of FIGS. 2a and 2b, when there are similarity values which exceed 218 the threshold, or the limit for either the size or the threshold has been met 220, a matching region is determined 224. In alternate embodiments, a matching region is only determined 224 in the cases where the similarity threshold is exceeded. The candidate region 304 which corresponds to the maximum recorded similarity value is the region in target image 110b which most nearly matches interrogation region 302 in reference image 110a. The disparity for the interrogation point is calculated 226 as the position of the matching region in target image 110b minus the position of interrogation region 304 in reference image 110a. In the exemplary embodiment, this disparity value can be saved as an unsigned scalar value. In general cases, the disparity can be a vector quantity with two coordinates. The disparity value is saved with information specifying the location of the interrogation point. Optionally, the size of interrogation region 304 can be saved with the disparity information as well.
If the current interrogation point is the last to be examined 228, the process comes to an end. Otherwise, the next interrogation point is selected 230 into the location variable, the size variable is reset 204 to the minimum value, and the threshold variable is reset 204 to the maximum value. Then execution continues with the selection 206 of the next interrogation region 304 in reference image 110a.
FIG. 6 illustrates a computer apparatus 600 according to the present invention. Program disk 610 contains a computer program for causing central processing unit (CPU) 602 to carry out the method described above. Stereoscopic camera 100 captures images 110a and 110b, storing them in image memory 604 in computer 600. After determining the disparity information 612, CPU 602 stores the information 612 in disparity map memory 606. Disparity information 612 can be exported from computer 600, or it can be used by programs in computer 600 which require depth information. In alternate embodiments, some or all of the components of computer 600 can be included in camera 100. In still other embodiments, images 110a and 110b can be computer generated images, rather than images of a real world scene.
The above description is included to illustrate the operation of exemplary embodiments and is not meant to limit the scope of the invention. The scope of the invention is to be limited only by the following claims. From the above description, many variations that would be encompassed by the spirit and scope of the present invention will be apparent to one skilled in the art.
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Two data sets are analyzed to determine disparity between them at various interrogation regions (302) of the data sets. The data sets can represent, for example, digital images, acoustical signals, or electrical signals. The size of interrogation regions (302) used for disparity analysis is varied dynamically. An initial interrogation region (302) from a reference data set is compared to several candidate regions (304) from a target data set. If none of the comparisons indicate a required level of similarity, the process is repeated with a larger interrogation region (302). This process of successively using larger interrogation regions (302) continues until either a maximum interrogation region (302) size is reached, or the required level of similarity is indicated in one of the comparisons.
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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0001] The U.S. Government may have certain rights in this invention pursuant to contract number N68936-99-C-0117.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to gas turbine engines and, more particularly, to methods and apparatus for assessing damage to engines.
[0003] Gas turbines are used in different environments, such as, for providing propulsion as aircraft engines and/or for generating power in both land-based power systems and/or sea-borne power systems. During normal operation gas turbine engines may experiences large changes in ambient temperature, pressure, and power output level, and although such changes occur during normal operation, such change may result in undesirable changes in engine dynamics.
[0004] To facilitate maintaining engine efficiency, at least some known turbine engines include a controller that continuously monitors the engine to ensure that mechanical, aerodynamic, thermal, and flow limitations of the turbo machinery are maintained. However, despite continuous monitoring of the turbine engine, undesirable engine performance may occur without detection by the controller. For example, an erroneous actuator position feedback, or an obstruction in the afterburner duct may cause the variable exhaust nozzle (VEN) of a gas turbine engine to exhibit anomalous behavior that may not be detectable until a physical inspection of the VEN is performed. However, continued operation with the anomalous behavior may adversely effect engine operating performance.
[0005] Variable area exhaust nozzles (VEN) on gas turbine engines typically are manipulated to regulate a pressure ratio in the engine. Physically, the pressure drop across the nozzle changes in response to changes in the effective nozzle area, which may affect, for example, a fan operating line, and a core engine pressure ratio. Known VEN control logic can detect position sensor failure or actuator failure, however, more subtle damage scenarios, such as a hole resulting from ballistics damage, would be compensated for by manipulating the VEN position, but the damage is undetected by the control logic unless the needed compensation exceeds the physical limits of the VEN.
BRIEF DESCRIPTION OF THE INVENTION
[0006] In one aspect, a method of assessing damage to machine components is provided. The method includes calculating an expected parameter value based on a first parameter value indicator, calculating an estimate of an actual parameter value based on a second parameter value indicator, the second parameter value indicator being different than the first parameter value indicator, determining if the calculated expected parameter value is different than the calculated estimate of the actual parameter value by a predefined limit, and generating a damage flag based on a result of the comparison.
[0007] In another aspect, apparatus for detecting damage in a gas turbine engine is provided. The apparatus includes a computing device including a processor and a memory communicatively coupled to the processor, the processor is programmed to execute a software product code segment including a detection boundary module, an estimator, and a comparator wherein the computing device is programmed to assess damage within an engine.
[0008] In yet another aspect, a gas turbine assembly is provided. The assembly includes a variable area exhaust nozzle including an inlet side, and an outlet side, and a computing device that includes a processor and a memory communicatively coupled to the processor wherein the processor is programmed to execute a software product code segment that includes a detection boundary module, an estimator, and a comparator, and wherein the computing device is programmed to assess damage within the gas turbine assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic illustration of a gas turbine engine;
[0010] FIG. 2 is an exemplary block diagram of a variable area exhaust nozzle damage detector that may be used with the gas turbine engine shown in FIG. 1 ;
[0011] FIG. 3 is a graph illustrating exemplary traces of an engine test;
[0012] FIG. 4 is a graph illustrating exemplary traces of a computer simulation test of a hole in developed in the afterburner duct of the engine;
[0013] FIG. 5 is a graph illustrating exemplary traces of results of the damage detector for engine test data;
[0014] FIG. 6 is a graph illustrating exemplary traces of results of the damage detector as applied to simulation data; and
[0015] FIG. 7 is a process flow diagram for a damage assessment process of the damage detector shown in FIG. 2 .
DETAILED DESCRIPTION OF THE INVENTION
[0016] FIG. 1 is a schematic illustration of a gas turbine engine 10 including a fan assembly 12 , a high pressure compressor 14 , and a combustor 16 . In one embodiment, engine 10 is a F414 military aircraft engine available from General Electric Company, Cincinnati, Ohio. Engine 10 also includes a high pressure turbine 18 and a low pressure turbine 20 . Fan assembly 12 and turbine 20 are coupled by a first shaft 24 , and compressor 14 and turbine 18 are coupled by a second shaft 26 .
[0017] In operation, air flows through fan assembly 12 and compressed air is supplied from fan assembly 12 to high pressure compressor 14 . The highly compressed air is delivered to combustor 16 . Airflow from combustor 16 drives rotating turbines 18 and 20 and exits gas turbine engine 10 through an exhaust system 28 . Exhaust system 28 includes a variable area exhaust nozzle (VEN) 30 .
[0018] FIG. 2 is an exemplary block diagram of a variable area exhaust nozzle damage detector 200 that may be used with gas turbine engine 10 shown in FIG. 1 . Damage detector 200 may be embodied in a processor coupled to engine 10 and configured to perform the below described processes. As used herein, the term processor is not limited to just those integrated circuits referred to in the art as processors, but broadly refers to computers, processors, microcontrollers, microcomputers, programmable logic controllers, application specific integrated circuits, and other programmable circuits. In the exemplary embodiment, damage detector 200 is embodied in a Full Authority Digital Electronic Control (FADEC) available from General Electric Company, Cincinnati, Ohio. Damage detector 200 is used to identify potential damage cases including holes, or other damage that causes an increase in the physical area downstream of the turbines and/or blockages, or erroneous position feedback signals, or other damage that causes a decreased physical area downstream of the turbines. Damage detector 200 includes a detection boundary module 202 that is communicatively coupled to a parameter value indicator 204 . In the exemplary embodiment, gas turbine engine 10 includes VEN 28 and parameter value indicator 204 is a nozzle actuator position feedback 204 . In an alternative embodiment, parameter value indicators 204 may include engine process parameters used to infer a nozzle actuator position feedback.
[0019] An effective area estimator 206 utilizes engine cycle data to determine a nozzle area implied by engine process parameters that are affected by the actual nozzle area. A comparator 208 receives signals from detection boundary module 202 and estimator 206 , and compares the received signals relative to each other and to a predetermined limit If the comparison result exceeds a pre-defined limit value, a damage flag 210 is generated. In the exemplary embodiment, a maximum expected value of effective nozzle area is computed based on parameter value indicator 204 . Additionally, other operating condition information may be used to infer a desired parameter value indicator. More specifically, the maximum expected value represents the detection boundary. An estimate of the actual effective nozzle area is then calculated in estimator 206 using engine cycle data 212 , including, for example, rotor speed, gas pressure or temperatures, engine power, altitude, Mach number, and fuel flow. The maximum expected value of the effective nozzle area and estimate of the actual effective nozzle area are compared at comparator 208 , and an estimated effective area greater than the detection boundary results in a damage flag 210 .
[0020] Effective area estimator 206 generates an estimated value of effective nozzle area as a function of engine cycle data 212 . In the exemplary embodiment, the function is a simple linear function of the inputs. In an alternative embodiment, the function is a neural network. In another alternative embodiment, the function is a nonlinear function of the inputs. Additionally, estimator 206 may be trained using real or simulated engine data, of both damaged and undamaged engines 10 . In yet another alternative embodiment, the function may be a physics-based model of an effective nozzle area that uses upstream parameters as inputs.
[0021] Similar logic, using a minimum expected value of effective nozzle area for the detection boundary, may be used to detect VEN or afterburner duct blockages or erroneous position feedback signals. During such conditions, the effective nozzle area is smaller than what would be expected based on the actuator position feedback value 204 . Such logic may be used in conjunction with the “maximum area” logic described above, and such use is consistent with the intent and operation of both types of logic.
[0022] FIG. 3 is a graph 300 illustrating exemplary traces of an engine test wherein damage detector 200 is implemented in software for a military aircraft engine, available from General Electric Company, Cincinnati, Ohio. The test includes engine cycle data and engine test data. During the engine test, a pre-existing hole in the side of the afterburner duct section was exposed which resulted in increasing the effective area downstream of turbines 18 and 20 . A first hole was exposed at partial power early in the test, prior to an elapsed time of forty (t=40) seconds. Accordingly, data shown in graph 300 represents a condition wherein the afterburner duct includes simulated pre-existing VEN damage. An additional hole was exposed from engine 10 , near the rear of the afterburner section after engine 10 was brought to maximum dry power (IRP) and after approximately forty-seven (t=47) seconds had elapsed. Fan speed trace 302 illustrates a response of fan speed (QN 2 ) to a sudden increase in effective nozzle area due to exposure of the second hole. LP turbine exit temperature (QT 5 ) trace 304 illustrates the response of LP turbine exit temperature to the initial increase in fan speed 302 . LP turbine exit pressure (QP 56 ), as shown in trace 306 , initially decreases in response to the increased exhaust area. Trace 308 illustrates a response of the exhaust nozzle actuator position feedback (QA 8 X). As the FADEC detects, and then compensates for the increased effective exhaust nozzle area, the control system commands the exhaust nozzle to close down. As the exhaust nozzle closes, it can be seen that fan speed, as shown in trace 302 , LP turbine exit temperature, as shown in trace 304 , and LP turbine exit pressure, shown in trace 306 , return to values near their pre-event values. Notably, in the exemplary case, the simulated damage was not sufficient to exceed the limits of the capability of exhaust nozzle 28 to correct for the damage, and as such may have gone undetected until physical inspection was performed.
[0023] FIG. 4 is a graph 400 illustrating exemplary traces of a computer simulation test of a hole developed in the afterburner duct of engine 10 . FIG. 4 illustrates the simulation results of injecting the equivalent of a 20 in 2 hole in the afterburner duct or nozzle area. The operating conditions are similar to those of the engine test shown in FIG. 3 . The damage is injected at the five second mark (t=5), and the corresponding increase in fan speed illustrated in trace 402 , and decrease in LP turbine exit temperature, illustrated in trace 404 and LP turbine exit pressure, illustrated in trace 406 are compensated for by a reduction in exhaust nozzle actual area, illustrated in trace 408 , commanded by the FADEC.
[0024] FIG. 5 is a graph 500 illustrating exemplary results of damage detector 200 for the engine test data. Graph 500 includes a throttle position (PLA) trace 502 , an effective exhaust nozzle area (AE 8 ) estimate trace 504 , and an AE8 Margin trace 506 . Trace 504 illustrates a detection boundary trace 508 , which is a computed estimate of effective nozzle area based on A8 actuator position feedback. In the exemplary embodiment, detection boundary trace 508 includes additional margin built in. An estimated AE8 trace 510 is an estimate of effective nozzle area based on engine cycle data 212 . At the beginning of the test (t=40), estimated AE 8 trace 510 is greater than detection boundary trace 508 due to the exposure of first hole. However, at approximately the forty-seven second time mark (t=47), the second hole is exposed. Estimated AE8 trace 510 responds by increasing initially due to additional exhaust area provided by the hole. As the FADEC begins to compensate, AE8 estimate trace 510 and detection boundary trace 508 decrease. When the second hole is exposed, the difference between estimated AE8 trace 510 and detection boundary trace 508 changes by approximately 30 in 2 as illustrated by graph 506 . AE 8 Margin trace 506 illustrates the difference between AE8 Estimate trace 510 and detection boundary trace 508 . In the exemplary embodiment, a signal represented by AE8 margin graph is used to set damage flag 210 . In the case of a nozzle or afterburner duct blockage, AE8 estimate graph 506 would illustrate a trace acting in an opposite direction and the difference between estimated AE8 trace 510 and detection boundary trace 508 would increase in a positive reference direction.
[0025] FIG. 6 is a graph 600 of results of damage detector 200 applied to simulation data. Graph 600 illustrates a damage trace 602 that would result from a 20 in 2 hole and a damage trace 604 that would result from a 40 in 2 hole. Each of traces 602 and 604 include a Detection Boundary trace 606 and 608 , an Estimated AE8 trace 610 and 612 , and an AE8 trace 614 and 616 . The simulation results show similar behavior as the engine test data shown in FIG. 5 , except that the simulated pre-existing damage is not present, therefore Estimated AE8 trace 606 , 608 is approximately equal to AE8 trace 614 , 616 . After an elapsed time of approximately five seconds during the simulation, damage to the engine corresponding to a 20 in 2 hole and a 40 in 2 hole is simulated as shown in traces 602 and 604 respectively. In each simulation, Estimated AE8 trace 610 , 612 and AE8 trace 614 , 616 increase sharply because the simulated damage presents a larger nozzle area permitting more flow through engine 10 . The FADEC compensates for the increased flow through the engine by closing exhaust nozzle 28 , reducing the nozzle area and restricting flow through engine 10 .
[0026] FIG. 7 is a process flow diagram for a damage assessment process 700 of the damage detector shown in FIG. 2 . Process 700 calculates 702 an expected parameter value based on a first parameter value indicator 204 , which is responsive to a damage symptom. In the exemplary embodiment, first parameter value indicator 204 is a position feedback signal for a gas turbine engine exhaust nozzle actuator. In an alternative embodiment, first parameter value indicator 204 may be any monitored parameter or parameter that may be inferred from other monitored parameters. The engine exhaust nozzle actuator position feedback signal may be selected because in one known damage scenario, such as, a hole in a wall of the engine afterburner duct, the engine FADEC compensates for the hole by causing the exhaust nozzle to close down. The position feedback signal indicates a repositioning of the nozzle in response to damage to the engine. An estimate of an actual parameter value is calculated 704 based on a second parameter value indicator. In the exemplary embodiment, the second parameter value indicated is a plurality of sensors monitoring machine parameters that may be combined to infer an estimate of the actual parameter value. In an alternative embodiment, the second parameter value indicated may be a redundant sensor monitoring the same parameter as the first parameter value indicator. The results of the calculated expected parameter value is compared 706 to the calculated estimate of the actual parameter value based on a predefined limit. If the results of the comparison exceed the limit, a damage flag is generated 708 . Damage flag 708 may indicate a hole or otherwise excess flow condition, or may indicate a blockage of the afterburner duct or a faulty actuator position feedback. Damage flag 708 may be used to initiate automatic corrective action, signal a visual and/or sonic warning, write an entry to a fault log, or may be used in concert with other flags to diagnose and/or report engine problems to a supervisory control system and/or human operator.
[0027] The above-described damage detector system is cost-effective and highly reliable. Each system includes a detection boundary module that is communicatively coupled to a parameter value indicator, an effective area estimator to determine a nozzle area, and a comparator that receives signals from the detection boundary module and the estimator and compares the received signals relative to each other and to a predetermined limit. If a result of the comparison exceeds a limit value, a damage flag is generated. Accordingly, the damage detector system facilitates operation and maintenance of machines, and in particular gas turbine engines, in a cost-effective and reliable manner.
[0028] Exemplary embodiments of damage detector system components are described above in detail. The components are not limited to the specific embodiments described herein, but rather, components of each system may be utilized independently and separately from other components described herein. Each damage detector system component can also be used in combination with other damage detector system components.
[0029] While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
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A method and apparatus for assessing damage to machine components is provided. The method includes calculating an expected parameter value based on a first parameter value indicator, calculating an estimate of an actual parameter value based on a second parameter value indicator, the second parameter value indicator being different than the first parameter value indicator, determining if the calculated expected parameter value is different than the calculated estimate of the actual parameter value by a predefined limit, and generating a damage flag based on a result of the comparison. The apparatus includes a computing device including a processor and a memory communicatively coupled to the processor, the processor programmed to execute a software product code segment that includes a detection boundary module, an estimator, and a comparator wherein the computing device is programmed to assess damage within an engine.
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REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority from U.S. Provisional Application No. 60/862,672, which was filed on Oct. 24, 2006, the disclosure of which is incorporated by reference.
FIELD OF THE INVENTION
[0002] Described herein is an embodiment of a water control apparatus that may be used in connection with a commercial mixing assembly or vehicle (e.g., a concrete mixer truck). More specifically, described herein is a water control assembly that may, alone or in combination with a concrete mixer vehicle or assembly, operate to monitor water volume usage vehicle/assembly operator use, manually or automatically control the addition of water to a mix, and/or transmit status data to a remote location.
REFERENCE TO RELATED ART
[0003] Concrete mixer trucks typically have two water flows that are of concern to the operator. One flow is the adding of water to the concrete batch. The second flow is the washing of the truck chute after the concrete has been dispensed. Issues related to these duel concerns have been found to manifest in a number of ways.
[0004] By way of example only, the ready-mix concrete used in construction applications m,ay typically be prepared at a batch plant and then transported by truck in a rotating drum to a job site. As the truck travels to a job site, the curing process for the concrete is underway. Therefore, it may be necessary for the driver (during travel or when at the job site) to add extra water to the batch so that the concrete maintains sufficient fluidity for pouring. However, this extra water may reduce the strength of the resulting concrete, or (if too much water is added) even ruin the load.
[0005] Accordingly, it would be advantageous to have a system that may accurately measure/control the amount of water being added to a mix (i.e., the slump) to ensure that the mix is within (or says within) a predetermined water-cement ratio (WCM).
[0006] By way of another example, when preparing a concrete batch, it is know that modern mixing vehicles may use a manually operable valve arrangement that permits the operator to fill the mixing drum with the slump. These manual valve arrangements may include flowmeters that indicate the amount of water being added to the mix. However, as mentioned above, these same mixing vehicles may also include a manually operable assembly that permits the vehicle operator to add water to the slump while in route. Specifically, the vehicles may include a lever (or the like) in the vehicle cab that allows the operator to add water to the mix from a pressurized tank of water mounted on each vehicle. The water being added in route may go through a flowmeter. However, when the flowmeter is positioned outside the vehicle cabin the operator has no way of knowing exactly how much water has been added. Further, currently available systems may also allow the operator to manually “crack” the valve open just enough to allow water to flow into the mix, but at a pressure or flow rate that is to low to be detected by the flowmeter (e.g., less than about 5 gallons per minute). Therefore, it may be possible for the operator to add water to the slump in a manner that is not detected by the flowmeter. In addition, over time the flowmeter itself may be subject to a variety of harsh conditions (e.g., acid wash, icing on cables, leaking connector, meter hanging up due to entrained dirt, and compressed air over ranging) that may damage or even destroy the meter.
[0007] Accordingly, it would be advantageous to have a water control system that allows better control and monitoring of the addition of water to the mix during all stages of production and delivery. It would also be advantageous to have a system whereby the stages of a mixing job could be tracked and reported to a remote location, such as a central tracking station. Indeed, such a system would address a long felt need in the industry for a reliable means of monitoring and controlling water use on mixer vehicles and assemblies.
SUMMARY OF THE INVENTION
[0008] The water control apparatus disclosed herein overcomes the issues raised by the prior art. The apparatus includes a flowmeter that may monitor the amount of water added to a mixer drum when a solenoid valve is actuated to allow flow into the drum. The flowmeter may be a non-mechanical flowmeter. Therefore, dirt, external corrosives, and compressed air do not affect the flowmeter's operation. The flowmeter is also accurate to 1%, thereby meeting the requirements of the U.S. Department of Transportation Federal Highway Administration FP-03 552.05. The solenoid valve may be actuated by a button in the truck cab, which replaces the manual valve usually located next to the driver. The solenoid valve is either fully on or fully off. Therefore, the ability for an operator to manually “crack” open a valve so that the flow is below a rate where it can be sensed by a flowmeter is eliminated. The amount of water being added may also be recorded by a control unit and transmitted to a remote location for record keeping.
[0009] More specifically, a water control apparatus that may be used with a commercial mixing vehicle may include a flowmeter unit in fluid Communication with a water source, an (optional) normally open valve unit, and a normally closed valve unit. The normally open valve unit may be removably connected to the flowmeter unit. The normally closed valve unit may likewise be removably connected to the normally open valve unit. Alternatively, the normally closed valve unit may be removably connected to the flowmeter unit, or to a conduit (not shown) positioned between the flowmeter unit and the normally closed valve unit. T he valve units may each include a power-actuated valve that may he triggered in response to commands from a control unit. The control unit may be activated by a switching device positioned in the vehicle cabin.
[0010] In operation, for example with a mixer truck, the normally open value unit may have a hose (or the like) and spray nozzle attached to permit a user to wash out tie truck and mixing equipment. A second hose or conduit may be connected at one end to the normally closed value unit and terminate at an opposite end in the mixer drum of the truck. Water may, therefore. The communicated from a source (e.g., a fixed water tank, truck mounted drum, etc.) to the flowmeter unit where the rate and/or volume of the water passing through the unit may be measured. Such measurements may be indicated on a display associated with the switching device. Water passing though the flowmeter unit may next pass through the normally open valve unit, and then on to the normally closed value unit.
[0011] Activation of the switching device by a user may result in the control unit causing the valve of the normally open valve unit to close, and the valve of the normally closed valve unit to open. Alternatively, the valves may he automatically actuated as Just described by the control unit using on board software and/or hardware programmed to cause water to be added at predetermined times or following predetermined events. Opening of the valve of the normally closed valve unit may thus cause an amount of water to be easily communicated from a water source and into the mixer drum of the mixer truck.
[0012] As a still further alternative, it will be appreciated that the control unit may be programmed to prevent the opening of the valve of the normally closed valve unit where the addition of water would cause the mix to exceed a predetermined water-cement ratio.
[0013] It will also be appreciated that a user of the water control apparatus would be prevented from manually “cracking” a valve open to add water to the mix. Indeed, since the power-actuated valves of the valve units are always either full open, or full closed. The flow rate of water through the flowmeter unit is maximized and the resulting accuracy of the water rate/volume measurement is increased.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Reference will now be made to the attached figures wherein like reference numerals refer to like parts throughout and wherein:
[0015] FIG. 1 is a planar environment side view showing an embodiment of a water control apparatus mounted on a mix truck, the apparatus being depicted as larger than normal for purposes of clarity;
[0016] FIG. 2 is a perspective side view of a an embodiment of a water control apparatus;
[0017] FIG. 3 is a perspective side view of the embodiment of a water control apparatus of FIG. 2 showing solenoids (or the like) mounted on the apparatus valves and a control unit;
[0018] FIG. 4 is a perspective end view of the embodiment of a water control apparatus of FIG. 2 ;
[0019] FIG. 5 is a perspective, partially exploded side view of the embodiment of a water control apparatus of FIG. 2 ;
[0020] FIG. 6 is a perspective, partially exploded top and side view of the embodiment of a water control apparatus of FIG. 9 ; and
[0021] FIG. 7 is a perspective side view of a normally closed valve unit.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Referring now to FIGS. 1 through 7 , a water control apparatus 10 , which may be used with a commercial mixing vehicle 100 having a mixer drum 102 , may include a flowmeter unit 12 in fluid communication with a water source 104 , an (optional) normally open valve unit 14 , and a normally closed valve unit 16 . The normally open valve unit 14 may be removably connected to the flowmeter unit 12 . The normally closed valve unit 16 may likewise be removably connected to the normally open valve unit 14 . Alternatively, the normally closed valve 16 unit may be removably connected to the flowmeter unit 12 , or to a conduit (not shown) positioned between the flowmeter unit 12 and the normally closed valve unit 16 . The valve units 14 , 16 may each include a power-actuated valve 18 , 20 . Specifically, valves 16 , 18 may each be a solenoid 19 , 21 controlled valve. Further, each valve 18 , 20 may be actuated in response to a command(s) from a control unit 22 that may be activated by a remotely positioned switching device 24 . The apparatus 10 may be powered by connecting the switching device 22 of the apparatus to the vehicle 100 power system. Alternatively, a lithium ion battery (not shown) or the like could be integrated into the control unit 22 . Each of the units 12 , 14 , 16 may have a molded plastic body formed using a variety of commercial known methods. However, it will also be appreciated that the units 12 , 14 , 16 may be constructed from a series of welded pipes outfitted with a flowmeter and the requisite valve assemblies.
[0023] Referring now to FIGS. 2 through 7 , the flowmeter unit 12 of the water control apparatus 10 may include a fluid conduit (not shown) that extends through the unit 12 and defines a water intake opening (not shown) on one side 26 of the unit 12 and a water outflow opening 28 on an opposite side 30 of the unit 12 . A flowmeter 32 that communicates with the fluid conduit and is capable of measuring low psi flow rates may be mounted on a face 34 of the unit 12 . The flowmeter 32 may, for example, be a COOLPOINT® vortex shedding type meter manufactured by Universal Flow Monitors of Hazel Park, Mich. The intake opening (not shown) of the unit 12 may be threaded, or include other manner of connector necessary to secure the unit 12 to a water conduit or hose 106 . However, as best shown in FIGS. 5 and 6 , the water outflow opening 28 may include a female connector 35 having series of grooves 36 that, as will be discussed below, permit the normally open valve unit 14 , or the normally closed valve unit 16 to be removably secured to the flowmeter unit 12 .
[0024] Referring now to FIGS. 2 through 6 , a recess 38 may be defined in another lace 40 of the flowmeter unit 12 into which may be mounted the control unit 22 . The control unit 22 may be electrically connected to, and include hardware and/or software that permit tile control and monitoring of the flowmeter 32 and the valves 18 , 20 . Further, the control unit 22 may be electrically connected to, and triggered by, the switching device 24 .
[0025] Therefore, as mentioned above, when activated via the switching device 24 the control unit 22 may operate to cause the valve 18 of the normally open valve 16 to close, and the valve 20 of the normally closed valve unit 16 to open. Additionally, or alternatively, the control unit 22 may operate to cause the valve 20 of the normally closed valve unit 16 to automatically open or close to allow (or prevent) an amount of water to flow into the concrete mixing drum. Accordingly, it will be appreciated that the control unit 22 may be programmed to maintain the concrete in the drum within predetermined water—cement ratio over a predetermined time. The control unit 22 may also include a global positioning system (GPS) receiver 27 and a radio transmitter 29 for transmitting data (e.g., flow meter information, valve open/close status) to a remote station.
[0026] Referring now to FIGS. 1 and 3 , the switching device 24 may include a housing 38 having a toggle switch 44 , a display 46 and known electronics (not shown). As shown, the switching device 24 may be positioned within the cabin of a mixer truck 100 . However, it will also be appreciated that one or more switching devices 24 may be positioned in a variety of locations on the truck 100 , or integrated into the control unit 22 .
[0027] Referring now to FIGS. 1 and 3 , as discussed above, activation of the toggle switch 44 may operate to transmit a command to the control unit 22 . The toggle switch 44 may be biased into an of position such that the valve 18 of the normally open valve unit 14 and the valve 20 of the normally closed valve unit 16 remain, respectively, in an open or closed orientation. The display 46 may function to indicate the volume of fluid/water flowing through the flowmeter unit 12 as measured by the flowmeter 32 , and monitored by the control unit 22 .
[0028] Referring now to FIGS. 2 through 6 , the normally open valve unit 14 may include a three-way fluid (or branching) conduit (not shown) that may extend through the unit 14 . Specifically, the conduit may define a water intake opening 48 on one side 50 of the unit 14 , a first water outflow opening on the opposite side 54 of the unit 14 , and a second water outflow opening 56 in a face 58 of the unit 14 . The power-actuated valve 16 may communicate with the three-way fluid conduit and may be mounted on a face 60 of the unit 14 .
[0029] As best shown in FIGS. 5 and 6 , the water intake opening 48 may include a male connector 62 having a plurality of tongues 64 . As such, it will he appreciated that the male connector 62 of the valve unit 14 may be removably fitted to the female connector 35 of the flowmeter unit 12 . The first water outflow opening of the normally open valve unit 14 may also define a female connector similar to the female connector 35 of the flowmeter unit 12 .
[0030] Still referring to FIGS. 5 and 6 , the second water outflow opening 56 may be closed off by a removable knockout portion (not shown). Alternatively, the opening 56 may be threaded or include a fitting or connector such that a hose or the like may be connected to the valve unit 14 at the opening 56 .
[0031] Referring now to FIGS. 2 through 7 , the normally closed open valve unit 16 may also include a conduit (not shown) that may extend through the unit 16 . Specifically, the conduit may define a water intake opening 68 on one side 70 of the unit 16 and a water outflow opening 72 on an opposite side 74 of the unit 16 . The power actuated valve 18 may be mounted on a face 76 of the unit 14 and communicate with the conduit.
[0032] As best shown in FIGS. 5 through 7 , the water intake opening 68 of the valve unit 16 may include a male connector 78 having a plurality of tongues 80 . As such, it will be appreciated that the male connector 78 of the valve unit 16 may be removably titled to the female connector (not shown) of the normally open valve unit 14 . The opening 72 of the valve unit 16 may be threaded or include a fitting or connector such that a hose or the like may be connected to the valve unit 16 at the opening 72 . For example, as mentioned above a conduit or hose 108 extending from the apparatus 10 to the mixer drum 102 of the mixer truck 100 may be attached to the apparatus 10 at the opening 72 .
[0033] Referring now to FIGS. 1 through 7 , in operation, a user should first be assured that the flowmeter unit 12 of the apparatus 10 is connected to a source of water 102 at the opening water intake opening (not shown) the side 26 of the unit 12 . The user should also connect a conduit to the opening 72 of the normally closed valve unit 16 . Then, once connected, a user may trigger the toggle switch 44 of the switching device 24 . Upon activation of the switch 44 , the control unit 22 may command the valve 16 of the normally open valve unit 14 (if present) to close off flow to the second water out flow opening 56 and command the valve 18 of the normally closed valve unit to open—causing water to flow through the water outflow opening 72 . As discussed above, the volume of water flowing through the apparatus may be measured by the flowmeter 32 , monitored by the control unit 22 , and indicated on the display 46 of the switching device 26 .
[0034] In additional, the radio transmitter 29 of the control 22 may function to transmit a signal to a remote location indicating that the valve 20 of the normally closed valve unit 16 has been opened. More specifically, when used in connection with a commercial mixing vehicle, a signal may be transmitted to indicate that an operator had commenced filling the mixing drum 102 with water. Further, the control unit 22 may transmit a second signal upon detection of fluid/water flowing through the flowmeter 32 when the normally closed valve 20 is in a closed position. Specifically, such a state would indicate that an operator of the mixing vehicle had completed a job and was now using water to clean off his or her vehicle using the nozzle 106 .
[0035] Having thus described my invention, various additional improvement and embodiments will become know to those of skill in the art that to not depart from the scope of the appended claims
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An embodiment of a water control apparatus is disclosed that may be used with a concrete mixing assembly. The apparatus may include flowmeter unit and a normally closed valve unit. The normally closed valve unit may be in fluid communication with, and removably connected to, the flowmeter unit. A control unit may be provide that may monitor the flowmeter unit and electronically control the opening and close of the normally closed valve unit. A switch may be also provided that may electrically communicate with the control unit. The activation of the switch being operable to cause the normally closed valve to open and result in the flow of water into a concrete mixing drum that is in fluid communication with the normally closed valve.
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CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application claims priority to U.S. Provisional Application 60/754,058, filed on Dec. 27, 2005, which is incorporated herein by reference in its entirety.
STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT
[0002] This invention was made with Government support under DMR 9984478 awarded by the National Science Foundation. The Government has certain rights in the invention.
BACKGROUND OF THE INVENTION
[0003] The present invention relates generally to the field of carbon nanotubes and specifically to the site-selective functionalization of carbon nanotubes.
[0004] Carbon nanotubes (CNTs) have been functionalized by several different methods, including acid-based wet-chemical oxidation, amidation, estrification, diimide-activation and solubilization, and hydrophobic adsorption of aromatic derivatives. These strategies typically rely on random defect creation or adsorption, which do not allow precise control over the location of the functional group on the CNT surface.
[0005] Functionalized CNTs have many potential applications due to their mechanical, electrical and electronic properties. However, the difficulty in controlling the location and type of functionalization hinders some of these applications.
SUMMARY OF THE INVENTION
[0006] One embodiment of the invention relates to a carbon nanotube comprising at least one functional group in a site-selective functionalization on the surface of the nanotube or a plurality of functional groups in an ordered arrangement on the surface of the nanotube.
[0007] Another embodiment of the invention relates to a method of functionalizing a carbon nanotube comprising providing a carbon nanotube, providing ions at a dose greater than 10 13 ions cm −2 having an energy greater than 1 keV on at least one first portion of the nanotube surface, and exposing the nanotube to an oxygen-containing medium such that at least one functional group is formed on the at least one first portion of the nanotube surface.
[0008] Another embodiment of the invention relates to a method of functionalizing a carbon nanotube, comprising providing a carbon nanotube, irradiating at least one exposed portion of the nanotube surface with ions to generate defect sites on the at least one exposed portion, and forming at least one functional group at a defect site.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIGS. 1A, 1B , 5 A, 6 A, 6 B, 7 A, and 8 A are schematic illustrations of CNTs according to the embodiments of the present invention. FIG. 1A shows ordered and site-selective functionalization of a carbon nanotube. FIG. 1B shows a device that is adapted to detect the selective attachment of a nanostructure. FIG. 5A shows attachment of Au nanoparticles onto a CNT. FIG. 6A shows attachment of fluorescent nanospheres. FIG. 6B shows attachment of fluorescent nanospheres onto a drop-coated mat of CNTs. FIG. 7A shows attachment of lysine containing Au nanoparticle markers onto a CNT. FIG. 8A shows attachment of azurin containing Au nanoparticle markers onto a CNT.
[0010] FIGS. 2A and 8D are plots of measured micro-Raman intensity versus wavenumber of CNTs according to the embodiments of the present invention. FIG. 2A shows micro-Raman spectra for both non-irradiated and irradiated CNTs. FIG. 8 D shows micro-Raman spectra for pristine azurin, and for non-irradiated CNTs and irradiated CNTs after treatment with azurin.
[0011] FIG. 2B is a plot of measured Fourier transform infrared (FTIR) absorbance versus wavenumber of CNTs according to the embodiments of the present invention. FIG. 2B shows FTIR spectra for both non-irradiated and irradiated CNTs after exposure to air.
[0012] FIGS. 3A, 3B , 4 A, 4 B, and 5 D are transmission electron microscopy (TEM) images of carbon nanotubes according to the embodiments of the present invention. FIG. 3A shows CNTs after irradiation by Ga + ions (10 16 cm −2 , 10 keV), wherein the white dotted lines represent the ion beam track. FIG. 3B shows a magnified view of the circled region in FIG. 3A in which lattice fringes from the graphene cylinders are visible. The images demonstrate that the multiwalled CNT structure is preserved even for CNTs with diameters about 20 nm. FIGS. 4A and 4B show the graphitic basal planes of non-irradiated and irradiated (Ga + ions, 10 16 cm −2 , 10 keV) CNTs, respectively. The images demonstrate that the crystalline structure is preserved upon irradiation under these conditions, and the large number of discontinuities and increased curvature of the basal planes suggest the generation of point defects during irradiation. FIG. 5D is a scanning TEM (STEM) image of site-selective attachment of Au nanoparticles on CNT bundles. The ion-irradiated portion of the underlying SiN membrane is damaged and sputtered away. The diffraction rings show that the Au nanoparticles attached to the irradiated portion of the CNT bundles possess a face-centered cubic (FCC) structure.
[0013] FIGS. 5B, 5C , 6 D, 7 B, 7 C, 8 B, and 8 C are scanning electron microscopy (SEM) images of carbon nanotubes according to the embodiments of the present invention. FIG. 5B shows attachment of Au nanoparticles on an aligned CNT bundle. The 500-nm dark band corresponds to the path traversed by a 10 17 cm −2 10 keV Ga + ion beam (middle image in FIG. 5B ). Bright spots on irradiated portions of CNTs (top image in FIG. 5B ) are Au nanoparticles, which are not observed on non-irradiated portions of CNTs (bottom image in FIG. 5B ). FIG. 5C shows attachment of Au nanoparticles on a drop-coated mat of CNTs irradiated by Ar + ions (10 16 cm −2 , 5 keV), wherein the same region of the CNT mat was imaged under secondary electron imaging (top image in FIG. 5C ) and atomic-number contrast imaging (bottom image in FIG. 5C ). FIG. 6D shows attachment of fluorescent nanospheres on a drop-coated mat of CNTs following Ar + irradiation (5×10 17 cm −2 , 5 keV). FIGS. 7B and 7C show attachment of Au-labeled lysine molecules on irradiated and non-irradiated portions of dispersed CNTs, respectively. FIGS. 8B and 8C show attachment of Au-labeled azurin proteins on irradiated and non-irradiated portions of dispersed CNTs, respectively.
[0014] FIG. 5E is a plot of measured energy dispersive X-ray spectroscopy (EDX) intensity versus energy of carbon nanotubes according to the embodiments of the present invention. FIG. 5E shows EDX spectra for both non-irradiated and irradiated CNTs after immersion in a solution containing Au nanoparticles. The peak corresponding to Au Mα on the irradiated CNT, but not on the non-irradiated CNTs, indicates site-selective attachment of Au nanoparticles.
[0015] FIG. 6C is a fluorescent micrograph of carbon nanotubes according to the embodiments of the present invention. FIG. 6C shows attachment of fluorescent nanospheres on a 1 mm×5 mm “†”-shaped macropattern created by Ar + irradiation (5×10 17 cm −2 , 5 keV).
[0016] FIG. 7D is a plot of measured x-ray photoelectron spectroscopy (XPS) intensity versus binding energy of carbon nanotubes according to the embodiments of the present invention. FIG. 7D shows XPS spectra of C 1 s, N 1 s, and Au 4 f core levels obtained from lysine (Au labeled) attached onto irradiated CNTs via amide bond formation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] In a first preferred embodiment, the present inventors have discovered that CNTs may be functionalized at predetermined locations on the CNT surface. At least one functional group (e.g., a single atom or a single group of atoms) is formed on the CNT surface in a site-selective functionalization of the CNT surface, preferably on ion induced defects sites on the CNT surface. A plurality of functional groups are arranged in an ordered arrangement on at least one portion of the CNT surface. Of course, if desired, a plurality of functional groups may be formed on more than one portion of the CNT surface, either in a serial fashion or simultaneously, and may, but need not, cover substantially the entire CNT surface. Of course, if desired, more than one type of functional group (e.g., carboxyls and allyls) may be formed on different portions of the CNT surface.
[0018] Preferably but not necessarily, focused ion beam (FIB) irradiation is used to functionalize multiwalled CNTs at predetermined locations. This approach involves the use of ions having an energy of at least 1 keV to irradiate particular locations of the CNT surface, such as particular segments of CNT axis, so as to site-selectively form at least one functional group on those particular locations. An arrangement of functional groups is ordered so long as its location on the CNT surface is not random. The concentration of functional groups on the irradiated portions of the CNT surface is higher than on the non-irradiated portions. For instance, the non-irradiated portions contain substantially no functional groups when measured microscopically or spectroscopically. The size of the irradiated locations, and hence the size of the functionalized portions of the CNT surface, can be adjusted down to a few nanometers by using increasingly smaller FIB spot sizes. Additional or alternative methods can be employed. For instance, irradiating through lithographic masks, or irradiating with scanning probe-tips or related near-field modification methods, can decrease the functionalized portions of the CNT surface down to atomic levels. Different types of ions may be used. For instance, Ga + or Ar + ions yield similar results, indicating that functionalization is independent of the projectile species used.
[0019] FIG. 1A shows exemplary formation of ordered and site-selective functional groups on precise locations of the CNT surface. A carbon nanotube 100 , such as a single-walled carbon nanotube (SWNT) or multiwalled carbon nanotube (MWNT), is irradiated with energetic ions, such as Ga + or Ar + ions, on a predefined location 102 of the nanotube surface. The location 102 may be defined by raster-scanning a focused ion beam within a defined area of the sample surface with micro- or nano-scale spatial resolution. Without wishing to be bound to any particular theory, the present inventors believe that ion irradiation of CNTs generates defects 104 , such as vacancy clusters or unsaturated bonds, on the irradiated portion of the nanotube surface. These defects 104 are reactive sites that facilitate the binding of functional groups 106 selectively at those defect sites on the irradiated portions of the nanotube surface. For instance, a covalent bond is formed between the functional groups 106 and the defects 104 , such as a covalent bond formed when an oxygen atom saturates an unsaturated CNT bond. Alternatively, a Van der Waals bond is formed between the functional groups 106 and the defects 104 , such as a Van der Waals bond formed between a functional group and a defect site on the nanotube surface having an electronic density that is different from that of other portions of the nanotube surface. The arrangement of the functional groups 106 is ordered and not random because the functional groups 106 appear localized to a particular portion of the surface of the nanotube 100 . For instance, the concentration of functional groups 106 is greater in the middle portion of the nanotube surface than on other portions. Types of functional groups include, but are not limited to, an alcohol, a carbonyl, a carboxyl, and an allyl. Oxygen-containing functional groups, such as alcohols, carbonyls, and carboxyls, may be formed by exposing the defects 104 to an oxygen-containing medium, such as air. Other types of functional groups may be formed by exposing the defects 104 to other types of controlled chemical ambients, such as hydrogen or halogen ambients. Functional groups containing carbon-carbon double- or triple-bonds, such as allyls, may, but need not, form spontaneously from the defect 104 even in the absence of a chemical ambient.
[0020] FIG. 1B shows an example of a device 110 comprising the functionalized carbon nanotube 108 of FIG. 1A . The nanotube 108 is disposed on a substrate 112 with electrical contacts 114 contacting the nanotube and disposed on opposite sides of the functional groups 106 located on the surface of the nanotube 108 . The functional groups 106 are located on the nanotube surface opposite the substrate 112 , for example the functional groups 106 are located on the entire exposed circumference of the nanotube, such that the functional groups 106 are readily accessible for site-selective attachment with nanostructures 116 that are deposited onto the device 110 from an aqueous solution. Preferably, but not necessarily, the attachment is chemically specific such that a given functional group or nanostructure is capable of binding only with one type of nanostructure. For instance, the attachment comprises protein-analyte interactions, such as streptavidin-biotin interactions wherein streptavidin is a first nanostructure known to specifically bind with biotin, a second nanostructure. The device 110 is adapted to detect an attachment of at least one of (1) a nanostructure 116 with a functional group 106 , or (2) a nanostructure 116 with a second nanostructure. Preferably but not necessarily, the device 110 is adapted to detect the attachment of a nanostructure by monitoring for a change in the electrical conductivity between the contacts 114 . For instance, an attachment involving a reduction/oxidation (redox) reaction between the nanostructure and the functional group results in the addition or removal of at least one electron to or from the functional group, which may be detected as a change in the nanotube's conductivity. Alternatively, the presence of an attached nanostructure may induce an electric field in the carbon nanotube and alter its conductivity, such as in a CNT-based chemical field effect transistor (ChemFET). Alternatively, detection may be performed by optical means. Of course, a nanotube with plural portions of its surface functionalized with plural types of functional groups can be used to simultaneously detect for the presence of plural types of nanostructures. Optionally, plural devices 110 may comprise an array of devices that detects attachment of plural types of nanostructures, wherein each device 110 detects for the presence of a certain type of nanostructure. For instance, the array provides detection, analysis, and separation of biomolecules on a single chip. The separation may be achieved using conventional microfluidic separation devices.
[0021] The CNTs may comprise single-walled or multiwalled carbon nanotubes, and my be prepared by a variety of methods, such as by chemical vapor deposition (CVD) or by the arc discharge method. The CNTs may comprise dispersed or aligned bundles. In one aspect of the invention, dispersed CNT bundles comprise a dense mat of CNTs, drop-coated from a toluene solution and air-dried on a silicon substrate. In another aspect of the invention, aligned CNT bundles are formed by selective CVD growth on silicon oxide templates, such as on lithographically patterned silicon oxide templates, as described in United States published application US-2003-0165418-A1, incorporated herein by reference in its entirety.
[0022] FIGS. 2A and 2B show selective defect creation and functionalization of irradiated portions of CNTs. FIG. 2A shows micro-Raman spectra (spot size ˜1 μm) for both non-irradiated and irradiated CNTs, wherein a larger D band for irradiated CNTs as compared to non-irradiated CNTs indicates a higher defect concentration for irradiated CNTs. FIG. 2B shows the FTIR spectra of CNTs irradiated with Ar + ions (10 17 cm −2 , 5 keV) and subsequently exposed to air. The FTIR spectra for irradiated CNTs show absorbance intensities at 1723, 1650, 1547, and 1455 cm −1 , which correspond to the chemical signatures of the functional groups O═C—O, C═O, C═C, and C—O—H, respectively. Spectra from non-irradiated CNTs do not show any detectable amounts of these functional groups. Without wishing to be bound by any particular theory, the present inventors believe that the high momentum transfer cross-sections (e.g., ˜5×10 −6 nm 2 for 30 keV Ga + ions) and the high energy density (˜420 eV/nm) imparted by ions having an energy of at least 1 keV leads to the formation of defects, such as vacancy clusters or unsaturated bonds, on the irradiated portions of the CNT surface. These defects, it is believed, are sites of increased chemically reactive which enable site-selective functionalization of the irradiated portions of the CNT surface by reaction with water and oxygen during air-exposure. The ability to localize the defects to particular segments of the CNT surface allows for spatially resolved functionalization of CNT segments. Exposure to other types of chemical ambients besides air allows for the formation of other types of functional groups.
[0023] To further probe the nature of the CNT defect structure, the present inventors irradiated CNTs using Ga + ions (10 16 cm −2 , 10 keV) and imaged the CNTs under TEM. FIG. 3A shows a dispersed CNT bundle, wherein the white dotted lines encompass the ion beam track. FIG. 3B is a TEM micrograph of an ion-irradiated portion of a CNT showing lattice fringes from the graphene cylinders. The cylindrical hollow of the irradiated CNTs are clearly seen in both images. These images confirm that the tubular CNT structure is preserved even for ˜20-nm-diameter CNTs. FIGS. 4A and 4B are high resolution TEM micrographs showing the graphitic basal planes of non-irradiated and irradiated (10 16 cm −2 , 10 keV Ga + ions) CNTs, respectively. The larger number of discontinuities and increased curvature of the basal planes in the irradiated CNT of FIG. 4B suggests the generation of point defects during irradiation. These images confirm that the crystalline structure of CNTs is preserved upon irradiation with 10 keV Ga + ions of a dose less than 10 18 cm −2 , preferably with a dose of about 10 16 cm −2 or less. These local site defects probably, but not necessarily, alter the electrical properties of CNTs and should be accounted for when irradiated CNTs are used for device applications.
[0024] In one preferred embodiment of the present invention, the functional group provides site-selective attachment of nanostructures to the CNTs. The attachment may comprise electrostatic or covalent attachment. The attachment may comprise an intermediary attachment entity, such as a polyelectrolyte that electrostatically binds between the nanostructure and the functional group of the CNT surface. The attachment may be performed by any suitable attachment chemistry, such as by a displacement reaction between allyl bromide and a carboxylic acid. Nanostructures include, but are not limited to, nanoparticles, such as metal nanoparticles, nanospheres, amino acids, and proteins. A nanostructure may be greater than 1,000 nanometers but is generally not visible to the naked eye. For instance, a nanostructure may be a microsphere, such as a Nile Red microsphere (Molecular Probes F-8784).
[0025] FIGS. 5 A-D demonstrate site-selective attachment of a gold nanoparticle to a functionalized CNT by electrostatic interactions. In one embodiment of the invention, the nanostructure comprises a gold nanoparticle, such as a negatively-charged gold nanoparticle, that is selectively attached to at least one functional group, such as carboxyl group, via a cationic polyelectrolyte. Multiwalled CNTs were synthesized either by CVD or by the arc discharge method. FIB irradiation experiments were carried out on aligned or dispersed multiwalled CNT bundles, in a FEI Strata DB-235 dual-beam system. Irradiation by Ar + ions was carried out on drop-coated CNT films in an ultra-high vacuum chamber fitted with a Perkin-Elmer model 04-303 differential ion gun. For the FIB experiments, aligned CNT bundles grown selectively on lithographically patterned templates of silica were used. 50 nm beams of focused ions (10-30 keV) were rastered across 300 to 800 nm-wide segments of aligned CNT arrays. Although smaller segments (e.g., 5 nm, determined by the focused ion beam spot size) can be functionalized, the present inventors deliberately chose larger length scales in order to allow facile visualization of the functionalized areas using conventional electron microscopy and spectroscopy techniques. The CNT arrays that were rastered by FIB irradiation were air-exposed and treated with poly(diallyldimethylammonium)-chloride (PDADMAC), a cationic polyelectrolyte known to enable electrostatic immobilization of gold nanoparticles on carboxylated CNTs. See K. Jiang et al., Nano. Lett., 3, 275 (2003). FIG. 5A shows the nanoparticle attachment scheme. The irradiated sample was immersed in an aqueous solution of PDADMAC, MW ˜100,000-200,000 and 1 mM NaCl solution for 30 min. The sample was thoroughly rinsed with a 1 mM NaCl solution and deionized water to remove loosely adsorbed polyelectrolytes, and immersed in a solution containing negatively charged gold nanoparticles (˜110 nm diameter) for 15 min followed by thorough washing with deionized water. For TEM and STEM examination, the irradiation and attachment experiments were carried out on drop-coated films of CNTs formed on 30-nm-thick electron-transparent SiN membrane windows by solvent evaporation. FIG. 5B shows that the gold nanoparticles attach only to the irradiated segments of the CNT, indicating an ordered arrangement and a site-selective functionalization of the CNTs with carboxyl groups. The 500-nm dark band corresponds to the path traversed by a 10 17 cm −2 10 keV Ga + ion beam. Bright spots on irradiated CNT segments (top image in FIG. 5B ) are gold nanoparticles, which were not observed in unirradiated CNT segments (bottom image in FIG. 5B ). No observable attachment is detected in the unirradiated regions. The nanoparticles are not dislodged from the irradiated segments despite repeated washing and rinsing, indicating strong electrostatic anchoring. Typically, nanoparticle anchoring is observed when CNTs are irradiated with 10 15 -10 17 cm 2 of Ga + ions at 10-30 keV, whereas dosing CNTs with ≦10 13 ions cm 2 does not result in any attachment. Some of the irradiated CNTs in the top image of FIG. 5B are welded together due to ion irradiation. This welding is suppressed by lowering the ion dosage below 10 17 cm −2 , for instance doses of about 10 16 cm −2 or less for Ga + ions. FIG. 5C shows that CNTs irradiated with 5 keV Ar + ions yield similar results, suggesting that the projectile species does not have a significant effect on defect creation and nanoparticle anchoring characteristics in this ion energy window for Ar + ions. FIG. 5D is a STEM image of site-selective attachment of gold nanoparticles on aligned CNT bundles. The irradiated portion of the underlying SiN membrane is damaged and sputtered away, and gold nanoparticles are seen only on the irradiated portion of the CNT. The diffraction rings in FIG. 5D show that the Au nanoparticles attached to the irradiated portion of the CNT possess an FCC structure. FIG. 5E is an EDX spectra which reveals a peak corresponding to Au Mα on the irradiated CNT, but not on the non-irradiated CNTs, indicates site-selective attachment of gold nanoparticles to functionalized CNTs.
[0026] FIGS. 6 A-D demonstrate site-selective attachment of a nanosphere to a functionalized CNT by covalent interactions. In one embodiment of the invention, the nanosphere comprises a carboxylated Nile-red fluorescent nanosphere, which displaces the bromine of a brominated allyl group in order to covalently bind to at least one allyl on the CNT surface. FIG. 6A shows the nanosphere attachment scheme. FIG. 6B shows the experimental setup. A mat of CNTs was drop-coated from a toluene solution and air-dried on a Si substrate. Allyl groups are generated on the CNT surface during ion irradiation with 5×10 17 cm −2 of 5 keV Ar + ions to a form a “†”-shaped macropattern (1 mm×5 mm for facile optical observation). The sample was treated with a few drops of HBr in CCl 4 , placed in a 0.1 M NaOH bath for 5 sec to neutralize the acid, thoroughly washed with deionized water, and dried in air. The sample was further treated with a 50 mM MES buffer solution, and 500 μl of a 2% aqueous suspension of Nile Red microspheres (Molecular Probes F-8784) was added to the covered bath. The bath was swirled for a few seconds, removed and air-dried for fluorescence microscopy imaging with a green filter. All procedures involving the fluorescent microspheres were performed in the dark prior to imaging. The carboxylated nanospheres displace bromine, revealing the regions where allyl groups are present. FIG. 6C is a fluorescence microscopy image under a green filter showing that only the regions with irradiated CNTs are selectively decorated with the nanospheres. Without wishing to be bound by any particular theory, the present inventors believe that the greater fluorescence intensity near the periphery of the irradiated macropattern suggests that the CNTs in these regions have the highest defect concentration. The relatively lower intensity near the center of the macropattern may be due to the sputtering of the CNTs due to high ion dose resulting from overlapping passes of the ion beam during rastering. FIG. 6D confirms that the fluorescent nanospheres preferentially agglomerate at defects sites, such as bent portions of the CNTs known to arise through the formation of nonhexagonal ring pairs. See A. Kumar et al., Langmuir, 16, 9775 (2000).
[0027] FIGS. 7 A-D demonstrate site-selective attachment of an amino acid to a functionalized CNT. In one embodiment of the invention, the amino acid comprises a lycine molecule bound to irradiated CNTs via the amide bond of a carboxyl group.
[0028] FIG. 7A shows the lysine attachment scheme. A mat of CNTs was irradiated by Ar + ions (10 16 ions cm −2 , 5 keV) and immersed in 15 ml deionized water containing 155 mg of the amide-forming mediator 1-ethyl-3-(3-dimethyl-amino-propyl)carbodiimide (EDAC). Next, 350 mg of L-lysine ethyl ester dihydrochloride 95% was added after 2 hours and the entire solution was left undisturbed for 24 hours. The samples were subsequently washed thoroughly with deionized water to remove loosely adsorbed reaction products and immersed in an Au nanoparticle hydrosol (pH ˜8.5) for 3 hours. The Au nanoparticle markers bind strongly to amino acids for visualization of selective attachment by SEM. The samples were again rinsed thoroughly with deionized water and dried in air prior to characterization by SEM and XPS. FIGS. 7B and 7C show attachment of Au-labeled lysine molecules on irradiated CNTs but not on non-irradiated CNTs, respectively, thus confirming site-selective attachment. Additionally, EDX analysis shows N—K α , O—K α , and Au M α X-ray peaks in EDX spectra only in irradiated CNTs, further confirming selective anchoring of lysine to irradiated CNTs. FIG. 7D shows XPS measurements that indicate that lysine is anchored to carboxyl groups in irradiated CNTs via amide bonds. This is seen from two characteristic amide signatures observed in lysine-derivatized CNTs: a N 1 s sub-band centered at 400.1 eV and a C 1 s sub-band centered at 286.9 eV. The sub-bands at 398.9 and 402.8 eV arise from the un-ionized and ionized amine groups bound to the Au nanoparticles surface, and are consistent with the presence of a higher Au 4 f 7/2 sub-band corresponding to Au(I) seen at 85.1 eV spectra in addition to the Au(0) state at 84 eV. The absence of imide and amine sub-bands at 399.1 and 400.3 eV, respectively, seen in the intermediate complex of CNTs and EDAC indicates that lysine displaces substantially all EDAC.
[0029] FIGS. 8 A-D demonstrate site-selective attachment of a protein to a functionalized CNT. In one embodiment of the invention, the protein comprises azurin ( Pseudomonas Aeruginosa ), a metalloprotein with tunable electron transfer properties and a potential cancer-fighting agent, which is bound to the CNT via electrostatic interaction with a carboxyl group on the CNT surface. FIG. 8A shows the azurin attachment scheme. Samples containing irradiated CNT bundles were immersed in a 5 ml bath of deionized water containing 1 mg azurin (maintained at a pH ˜5) for 2 hours. The pH was maintained below the pI of azurin to retain a residual positive charge on the biomolecule to enable attachment. The sample was then removed, washed thoroughly with deionized water and dried prior to characterization by Raman spectroscopy. Selected samples of azurin were also marked with Au nanoparticles prior to attachment with irradiated CNTs, to enable visualization by SEM. FIGS. 8B and 8C show attachment of azurin on irradiated CNTs but not on non-irradiated CNTs, respectively, thus confirming site-selective attachment. Attachment occurred only for pH<8, which corresponds to the pI of azurin, indicating electrostatic anchoring. Irrespective of the pH, there was no detectable attachment of the azurin on to unirradiated CNTs. FIG. 8D shows spatially resolved micro-Raman spectra that confirm azurin's attachment only onto irradiated CNT segments. Azurin-anchored CNT segments exhibit two strong Raman modes at 291 and 353 cm −1 that are characteristics of Cu—S (Cys) stretching in tetragonal or distorted tetrahedral coordination. These spectral signatures are not detectable in non-irradiated CNTs treated with azurin, confirming site-selective anchoring of the protein to irradiated CNTs. Spectra from pristine azurin also show Cu—S (Cys) stretching modes, but at higher wave numbers of 377 and 414 cm −1 (with a shoulder at 435 cm −1 ) associated with trigonal planar coordination. Thus, azurin's structure, and hence its polarization, are altered upon immobilization on a CNT. However, the retention of the Cu—S (Cys) spectral signatures indicates that that the immobilized protein is quite robust in nonphysiological environments and retains it redox-activity. These features are promising for realizing protein-CNT devices where the correlation between the protein conduction state and the type of immobilization is used as means to fingerprint and detect analytes, or tune protein orientation and activity with analytes via electrical signals through the CNT.
[0030] The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The description was chosen in order to explain the principles of the invention and its practical application. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents.
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A method of functionalizing a carbon nanotube includes providing a carbon nanotube, irradiating at least one exposed portion of the nanotube surface with ions to generate defect sites on the at least one exposed portion, and forming at least one functional group at a defect site. The method optionally includes attaching a nanostructure to the at least one functional group.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the separation of gaseous mixtures by selective adsorption, and more specifically to a pressure swing adsorption system designed to purify and quantitatively recover a plurality of components from a multicomponent gaseous mixture. Pressure swing adsorption is an art-recognized method which may be viewed as a four-step process such as the following. The adsorption bed is pressurized by entry of gas from the bottom of the bed while the top end of the bed is closed. This is referred to as the pressurization step. The next step is high pressure feed, wherein feed gas enters under pressure from the top of the column and effluent is allowed to escape from the bottom of the column. At the conclusion of this step the column is closed at both ends and the pressurized gas is then released by opening the top end of the column. This is referred to as the blowdown step. After the pressure has been reduced to a predetermined level by blowdown, the column is next purged of remaining product by feeding recycled product gas into the bottom end of the bed and allowing the gas remaining in the column to be forced out of the top end as effluent. This step would normally be terminated at the point where the purging gas reaches the top end of the column. The effluents from the blowdown and purge steps contain the component adsorbed by the column. This is generally referred to as the secondary product of the column. The primary product is the component or components which pass through the bed unadsorbed, i.e., the high pressure feed effluent.
Pressure swing adsorption has been used in numerous applications, including the separation of carbon dioxide and hydrogen from the effluent of a shift convertor in a hydrocarbon reforming plant, and the recovery of hydrogen and methane from the effluent gas of a hydrodesulfurization plant, as discussed below. As normally practiced, the process results in the non-quantitative recovery and purification of a single secondary product, and the marginal enrichment of a primary product. By contrast, complementary pressure swing adsorption, as presently disclosed and claimed, allows for the purification and quantitative recovery of two or more components from the feed gas. This is accomplished by feeding the exhaust from a column selective for one component into another column which is selective for another component.
2. Prior Art
Pressure swing adsorption systems designed for fractionation of gaseous multicomponent mixtures by selective adsorption are well known in the art. See e.g. U.S. Pat. Nos. 3,138,439, 3,142,547, 3,788,037, 3,221,476, 3,430,418, 3,720,042, 3,102,013, 3,149,934, 3,176,444, 3,237,379, 3,944,400, and 4,000,990.
U.S. Pat. No. 4,329,158 discusses the separation of oxygen from air using pressure swing adsorption. The process therein uses a first bed which adsorbs water and carbon dioxide and a second bed for the adsorption of nitrogen, which leaves an oxygen rich primary effluent product.
U.S. Pat. No. 4,264,340 discusses a similar pressure swing adsorption system wherein the secondary nitrogen component collected by the second bed is used to rinse both the first and second beds.
U.S. Pat. No. 4,171,206 discusses a pressure swing adsorption system for the separation of carbon dioxide and hydrogen from the effluent of a shift convertor in a hydrocarbon reforming plant. A first bed adsorbs carbon dioxide, a second bed adsorbs tertiary impurities consisting primarily of carbon monoxide and methane, and hydrogen is recovered as the primary component.
U.S. Pat. No. 4,171,207 discusses the use of pressure swing adsorption for the recovery of hydrogen and methane from the effluent gas of a hydrodesulfurization plant. A first bed adsorbs the C2-C6 hydrocarbon impurities and a second bed adsorbs the methane, leaving the enriched hydrogen component as the primary product.
It is significant that the prior art does not recognize nor teach a process wherein a plurality of columns adsorb each of the several components desired to be purified. Nor does the prior art teach a process wherein the several components to be purified are similar in nature such that a separation by selective adsorption would be difficult to accomplish. The prior art also does not teach a process wherein the product from a given column is used as feed for a complementary column. None of the processes taught by the prior art would be effective in the difficult separations to which the present invention is directed, e.g., complementary adsorption and purification of both nitrogen and oxygen from air. The most that the prior art processes could achieve in this regard would be a purification of one of these components and an enrichment of the other component in a mixed primary product. The prior art does not suggest the unexpectedly high degree of purification and recovery of each of these components achievable by the present process, nor the efficiency with which the present process achieves this result.
SUMMARY OF THE INVENTION
Complementary pressure swing adsorption is a method for achieving difficult separations and for purifying and recovering multiple components from a multicomponent gaseous mixture. A plurality of adsorption beds is used, each bed containing an adsorbent which is selective for one of the components to be recovered. Furthermore, the secondary product of one bed, that is, the blowdown and purge effluent, is used partly or wholly as the high pressure feed for another bed containing a different, or complementary adsorbent. This highly efficient system allows for the purification and quantitative recovery of two or more components from the multicomponent mixture, which result has not previously been achieved in the art.
Beyond the key elements listed above, the invention may encompass numerous embodiments. For instance, a single set of columns may be used, with one column being selective for each of the components to be recovered. In this case, each column may be purged and pressurized with recycled high pressure feed effluent from the same column, which effluent has been stored in a surge tank connected to the column via a flow conduit and, optionally, a compressor. For the separation of two components this would involve only a single pair of columns. In the preferred embodiment, two sets of columns would be used, with each set having one column selective for each of the components to be recovered. In this instance each column may be purged and pressurized with high pressure feed effluent from its duplicate column in the other set, containing the same adsorbent, the effluent again being fed to it via a flow conduit and a compressor. For the separation and recovery of two components, this embodiment would involve the use of two pairs of columns, as shown in FIG. 3.
In any of the embodiments, the columns may be purged and pressurized with high pressure feed effluent from the same or a duplicate column, i.e., a column containing the same adsorbent, as discussed above, or they may alternatively be purged or pressurized with purge effluent, blowdown effluent, or a mixture thereof, from another column containing a different adsorbent.
The high pressure feed for each column may consist exclusively of purge and blowdown effluent from a column containing a different adsorbent, or in the preferred embodiment, may be mixed with the raw multicomponent gaseous mixture for this purpose.
Complementary pressure swing adsorption may be used, for instance, in the purification and quantitative recovery of both nitrogen and oxygen from air. In this system, columns selective for nitrogen may contain the adsorbent zeolite 5A, and columns selective for oxygen may contain either the adsorbent zeolite 4A or the adsorbent carbonaceous sieve 5A. There is particular need for such a system on tactical aircraft, where oxygen is necessary for life support and nitrogen is necessary to blanket depleted fuel tanks. Efficiency under these circumstances is highly important, insofar as it is necessary to conserve engine bleed air for other onboard systems. Such a system may also find utility in hospitals, chemical plants and refineries, as well as in the metallurgical and semiconductor industries.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a two-column system for purifying and recovering two components from the multicomponent gaseous mixture, wherein the high pressure feed effluent from each column is stored in a surge tank and recycled therefrom into the same column for pressurization and purge. This may be accomplished via separate influent and effluent conduits and valves, or via a single conduit and a single two-way valve which may be regarded as being both an influent and an effluent valve. The blowdown and purge effluents from each column, i.e., enriched-A and enriched-B, are channeled into the high pressure feed line for the complementary column.
FIG. 2 shows the four steps in a basic pressure swing adsorption cycle for a single column. Step 1 is pressurization, step 2 is high-pressure feed, step 3 is blowdown, and step 4 is purge.
FIG. 3 is representative of the preferred embodiment, and shows a four column system for recovering two components. Columns 1A and 2A contain adsorbent A selective for component A. Columns 1B and 2B contain adsorbent B selective for component B. Pressurization and purge conduits, carrying high pressure feed effluent from each column to its duplicate column containing the same adsorbent, are marked with the letter (a). High pressure feed conduits, carrying blowdown and purge effluent from each column to the high pressure feed line have a complementary column containing a different adsorbent, are marked with the letter (b). It is noted that this effluent could alternatively be carried to the feed line of the other complementary column where appropriate. Components A and B are withdrawn as products from the conduits marked (a), as shown. Compressors for increasing pressure and relief valves to surge tanks for decreasing pressure are not shown.
DETAILED DESCRIPTION
The complementary pressure swing adsorption apparatus comprises a source of raw multicomponent gaseous mixture which is connected via flow conduits, compressors and influent valves to the top end of each of a set of adsorption columns. These flow conduits are the high pressure feed lines. Flow conduits also lead into influent valves in the bottom end of each bed, for purge and pressurization purposes. In a system comprising a single set of adsorbent columns with one column being selective for each of the components to be recovered, these conduits lead from surge tanks which collect the high pressure feed effluent of that column via a flow conduit leading from an effluent valve in the bottom of the column. Separate influent and effluent valves and conduits may connect the surge tank with the column, or a single conduit may be used, which connects to the column via a two-way valve. In this instance, the two-way valve is regarded as being both an influent and an effluent valve. In a system with two or more sets of adsorption columns, each of these conduits connects with an effluent valve at the bottom end of an identical column, containing the same adsorbent, and carries a portion of the high pressure feed effluent from the latter column. This is the preferred embodiment. Alternatively, these conduits may lead from the top end of a complementary column containing a different adsorbent, in which case they would carry the purge and blowdown effluents from the latter column, to be used as purging and pressurizing agents in this instance. In all cases, these conduits may be equipped with compressors to increase pressure when necessary, and they also have relief valves leading into surge tanks to reduce excess pressure.
Additionally, and in all embodiments, each column has a flow conduit leading out of an effluent valve in the top end of the column, which flow conduit connects via a valve into the high pressure feed line for a complementary column containing a different adsorbent. These conduits permit the blowdown and purge effluent from the first column to be used as the high-pressure feed for the second, complementary column. The valves connecting these conduits to the high-pressure feed lines operate so that the effluent may be mixed with raw feed for this purpose, or so that it may be used as the sole source of high pressure feed. See FIG. 3. These conduits are also equipped with compressors to increase pressure and valves leading to surge tanks to relieve excess pressure. In the preferred embodiment two sets of columns are used, i.e., two pairs of columns where two components are being recovered.
Each column hence has a top end with an influent valve and an effluent valve, and a bottom end with an influent valve and an effluent valve. Where a single set of columns is used and a portion of the high-pressure feed effluent of each column is recycled into the same column as purge and pressurization influent, the influent valve and effluent valve may be a single two-way valve, as discussed above.
The ratio of pressures used for each step in the process are more critical than are the absolute pressures. Pressurization begins at low pressure and progresses to high pressure. High-pressure feed is maintained at high pressure. A compressor maintains this pressure in the high-pressure feed lines throughout the cycle. Blowdown begins at high pressure and proceeds to low pressure. Purge is maintained at low pressure. In this description, low pressure may be either atmospheric pressure or subatmospheric pressure, and high pressure is superatmospheric pressure.
In carrying out the process, the four basic steps of pressure swing adsorption, as discussed above and in FIG. 2, are followed in a cyclic manner. In a time sequence, each column is pressurized by the appropriate flow conduit, after which high pressure feed, blowdown and purge follow. The cycles for each column are integrated so that effluents from one column may be used as influents for another in an efficient manner. The cycle is carried out for a period of time appropriate to maximize purity and recovery at which point the various products are recovered via valves in the flow conduits carrying the high pressure feed effluent from each column, as shown in FIG. 3.
EXAMPLE
On tactical aircraft and in other potential applications as discussed above, the preferred four column system of FIG. 3 may be applied to the purification and quantitative recovery of two components, nitrogen and oxygen from air. For this application, columns 1A and 2A may be regarded as being those columns selective for nitrogen, and columns 1B and 2B may be regarded as those columns selective for oxygen. The adsorbent in columns 1A and 2A is hence zeolite 5A, and the adsorbent in columns 1B and 2B is carbonaceous sieve 5A.
The process may be started simply by feeding air (multicomponent gaseous mixture) into each column via the high pressure feed conduits, for pressurization. In the preferred mode, however, the columns selective for nitrogen are primed with oxygen and the columns selective for oxygen are primed with nitrogen. The priming gases may be introduced either via the pressurization and purge conduits or via the high pressure feed lines. In any case, this initial step represents the first pressurization of the columns. Air (multicomponent gaseous mixture) is next introduced into the columns for the high pressure feed step. This step proceeds until the front end of the high pressure feed gas has reached the bottom of the column. The effluent from this step is collected by the flow conduits (a) and carried to the duplicate column containing the same adsorbent, for use as pressurization and purge influent, as shown in FIG. 3. Each column is next blown down and purged, the effluent from these steps being collected by the flow conduits B and carried to the high pressure feed line of a complementary column containing a different adsorbent. (It is noted that the effluent could alternatively be carried to the high pressure feed line of the other complementary column.)
The process is now ready for the second cycle. Each column is pressurized with recycled high pressure feed effluent collected from the duplicate column during the previous cycle. The high pressure feed step then commences, using air (multicomponent gaseous mixture) mixed with the blowdown and purge effluent. Cycles continue until a maximal state of recovery and purity for the nitrogen and oxygen components has been reached, and the nitrogen and oxygen components are then collected via valves in the flow conduits carrying the high pressure feed effluent from each column, as shown in FIG. 3.
It will be appreciated the numerous changes and modifications may be made in the above described embodiments of the invention without departing from the scope thereof. Accordingly the foregoing description is to be construed in an illustrative and not in a limitative sense, the scope of the invention being defined solely by the claims which follow.
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Complementary pressure swing adsorption is a method of purifying and quantitatively recovering a plurality of components from a multicomponent gaseous mixture. A plurality of adsorption columns is used, each containing an adsorbent which is selective for one of the components to be recovered, but not the others. Blowdown and purge effluent from each column is used as high-pressure feed for a complementary column containing a different adsorbent. Nitrogen and oxygen may be separated from air, for use on tactical aircraft or in hospitals and various industries.
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CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of pending U.S. Provisional Application Ser. No. 60/173,033, filed Mar. 19, 2007, titled “Conforming Protective Leg Guard Device” which is herein incorporated by reference.
BACKGROUND
[0002] When athletes and other participants in contact sport such as soccer, hockey, rugby, football, baseball, etc. desire protection for their exposed limbs, they utilize some of the available devices such as padded socks, shin guards, and the like. These devices are meant to protect the shins and sometimes calf areas of the limb by providing a rigid outer shell, and in some cases, a soft material adhered to the rigid body wherein the soft side contacts the user's limb. Soccer is notable as most of the impact and injuries from the sports occur in the player's shins and calves. With the increasing popularity of soccer and participation in baseball and hockey, especially by the youth, preventable injuries should be minimized as much as possible.
[0003] It is very common that a soccer player is impacted in the calf area as well as along the shin, and given the soft tissue in the calf area, with the force of such impacts causing many fractures. The typical shin guard offers some protection for the shin area, although it is now known that the effectiveness of such protection is not optimal.
[0004] Typical shin guards are effective in absorbing about 70% of the impact energy and have less than optimal material to absorb large quantities of energy, which might explain the increasing number of fracture injuries, even when the user is wearing a shin guard. Further, shin guards are typically worn to protect the shin leaving the other spheres of the limb exposed to impact-type injuries. Due to the rigid materials that are used for shin guards, the product is typically preformed to sizes and users have to fit and use the available sizes, without regard to the uniqueness of the limb. In particular, there have not been any known manufactured limb guard for arms.
[0005] It is therefore recognized that an athlete may be wearing a protective device such as a shin guard but does not gain the full protection that she needs for a contact sport. The need to offer increased protection for the exposed limbs in athletic activities is known. This invention discloses a full body protection for the limb area that is conformable to fit the shape of the limb and offers increased absorption for impact-type injuries.
SUMMARY
[0006] The present invention provides a conformable protective device for exposed limbs such as arm and leg parts from impact-type injuries, especially for athletic and sports activities. The present invention provides a conformable protective device that substantially protects the whole exposed limb and not only a side, as with the typical shin guard. The conformable protective device of the present invention preferably comprises an outer soft layer that substantially covers the conforming component of the protective device. The conforming component of the present invention is substantially flexible to form a fit in the manner of the shape of the user's limb to protect the whole—front, side and rear of the limb.
[0007] The present invention also provides a multilayer device that provides for impact absorption, impact dissipation and residual absorption. It is an objective of the present invention to provide a protective device that can be sufficiently flexible to form around the user's limb and provide more than adequate protection against impact-type injuries. The flexibility of the device of the present invention provides an advantage over typical shin guards and calf guards as the protective device is preferably made from a single or even multiple devices for use to protect legs from injury.
[0008] The present invention further provides a multilayer impact absorption material that may include a layer of gel, inflatable bulb or other solutions that may serve the impact modification purpose as well as being usable in a thin form as a protective device for athletes.
[0009] These and other aspects of the present invention will become apparent from the disclosures together with the included drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective side view of a conformable protective device for limbs according to the present invention.
[0011] FIG. 2 is a side perspective view of a conformable protective device for limbs according to the present invention.
[0012] FIG. 3 is a perspective view of a conformable protective device for limbs showing the fit in a limb according to the present invention.
[0013] FIG. 4 is a perspective view of a conformable protective device for limbs showing the fit on an arm according to the present invention.
[0014] FIG. 5 is an expanded view of a conformable protective device for limbs according to the present invention.
[0015] FIG. 6 is another expanded view of a conformable protective device for limbs according to the present invention.
[0016] FIG. 7 is an expanded and spread view of a 3-layer conformable protective device for limbs according to the present invention.
[0017] FIG. 8 is an expanded and spread view of a 4-layer conformable protective device for limbs according to the present invention.
DETAILED DESCRIPTION
[0018] FIGS. 1-8 illustrate embodiments of the present invention. The embodiments of the present invention depict in general, the invention and are not intended to be limiting. In this disclosure, terms such as conformable limb guard, protective device for limbs and conformable device are used interchangeably to represent the present invention of a device usable to protect limbs from impact-type injury associated with activities such as sports. The present invention provides a substantially conformable protective device usable to prevent impact-type injury in athletic events such as soccer, rugby, cricket, football, baseball, etc. wherein the shin, calf, arm or other limbs are exposed. The present invention provides a conformable material that forms to fit the limb of a user. Generally, the present invention provides a conformable protective device having layers wherein a first (an outermost) layer, even without a covering, serves to absorb an impact, at least a second layer serves to support the outermost and impact absorbing layer while reacting to the diminished impact force, and preferably a tertiary layer that absorbs any residual force. In each of these embodiments, the innermost layer may contact the skin of the user and is preferably suitable for such contact without any undue damage to the skin of the user.
[0019] In particular, FIG. 1 illustrates an embodiment of the present invention in the form of a conformable limb guard 10 having a conformable shell 100 that covers at least three (3) layers of impact absorbing material. In some instances, a single layer serves as the conformable shell and the outermost impact absorbing layer 120 . In the illustrated embodiment, the outermost layer 120 is adhered or operably attached to the shell 100 . There is preferably an intermediate layer 130 and yet another layer of energy absorbing material 140 . While the conventional shin guard or other protective devices provide a hard and commonly pre-molded element as the outermost layer and inner layers of foam or other dampening material; the present invention provides at least three (3) layers of energy absorbing material formed to allow for a fit that is not pre-molded as described below. The outer conforming shell 100 of the present invention preferably is of the length that sufficiently covers the area of a limb that the user intends to protect from impact-based injury. In some instances, the conforming shell 100 covering may be decorative or have some insignia that displays form, language, advertisement, branding or a combination of such displays. The conforming shell 100 may be made of fabric or garment type material. This fabric or garment serves to cover the outer impact absorbing layer of the present invention.
[0020] The outermost impact absorption layer 120 of the present invention is preferably made from material that is conformable and provides impact absorption. Such materials include Sorbathane, Impact Modified Polymethylmetracrylate (IM PMMA), High Molecular Weight High Density Polyethylene (HMW HDPE), Neoprene, latex, polypropylene, KEVLAR, 3D braided composites, and the like. The inventor recognizes the use of different materials for impact absorption and the advances yet to be made in such materials. This disclosure intends to utilize such advances as within the scope of this invention. The materials usable in the present invention are preferably effective in thin configurations to provide effectiveness without the unneeded bulkiness to make the product cumbersome to use. Each layer of the present invention is preferably made to absorb impact and dissipate the impact energy. Preferably, the outermost layer 120 is sufficiently conformable or malleable to be formed into the full limb protective device of the present invention as illustrated in FIG. 1 . As shown in FIGS. 1 and 2 , the protective device of the present invention may be wrapped around the limb needing protection and may form a seam 110 as illustrated. FIG. 2 is an embodiment of the present invention as it is fully formed about the limb of a user.
[0021] In each instance according to the present invention, the layers, whether the innermost or the outermost impact absorption layers are preferable made from material that serve to absorb and dissipate the impact associated with the sports activities. Conventional shin guards provide an outermost rigid casing with a softer inner layer, in contrast to the present invention which provides conformable impact absorbing layers with each layer suitable to absorb the impact energy and prevent the injuries that are commonplace in such sport activities. Another benefit of the present invention is the ease in protecting the whole limb, not only the front or occasionally the back of the limb. The present invention provides coverage due to the conformability to all the limbs, thus providing an increased protection to the user. It is an added advantage that the user needs not be concerned about the shape of his or her limb, given the flexibility provided by the conformability of the device.
[0022] FIG. 3 is an embodiment of the present invention illustrating the conformable protective device 30 as described in FIG. 1 having an extended fabric portion 150 . Such fabric or garment portion according to the present invention may be an extension of the outer conforming shell 100 or a designed band to further secure the conformable device of the present invention when in use.
[0023] FIG. 4 is an embodiment of the present invention illustrating the conformable protective device for limbs 40 used on a front part of an arm. The conformable limb guard device of the present invention for an arm 400 is usable protect all sides of an arm and similar to the device as illustrated for the leg in FIGS. 1-3 . It should be noted that the device of the present invention may be used to protect the upper arm (not shown).
[0024] FIG. 5 is an unwrapped embodiment 50 of the present invention displaying the ends 510 and 520 that are usable to attach one end to another end to form the conformable limb guard of the present invention. The ends 510 and 520 may be made from any combination of materials usable to operably attach or adhere two ends of the conformable material of the present invention. Such combinations may include zippers, Hook and Loop, Velcro® locking systems, repositionable adhesives, or other systems usable individually or in combination to operably attach or adhere the ends of the conformable limb guard. Where the closing or attachment systems include the use of an adhesive, such adhesives should be repositionable to facilitate multiple and repeated usage of the conformable limb guard.
[0025] Referring now to FIG. 6 , illustrating an embodiment of the present invention in a more rectangular pattern. While not wishing to be restricted to the illustrated embodiment, the recloseable portion of the protective device 610 and 620 is preferably broader to accommodate the variations in body contours and provide effective seal. As discussed in other embodiments, the ends of the layers of the present invention may comprise at least a means to close join or operably attach the ends to form the conformable protective device for limbs. In some cases, such closure means may be an adhesive, zipper or mechanical closing process or product such as Velcro® hook and loop systems.
[0026] FIGS. 7 and 8 are expanded and schematic illustrations of the 3- and 4-layer compositions according to the present invention. These illustrations show the layers of impact absorbing material that are usable in the present invention.
[0027] A layer of the present invention, preferably not the outermost ones, may be an inflatable bulb instead of an impact absorbing material. The purpose of such inflatable layer would be to provide impact absorption in the inflated space. It is also recognized that a gel-filled layer suitable to absorb impact-type energies can be usable according to the present invention. If gels, inflatable bulbs, or other solution based impact absorption material is used in lieu of traditional impact absorption material, efforts to prevent the leakage or otherwise damage to the effectiveness of such layers should be incorporated.
[0028] It is noteworthy that some of the structures described in the present invention in single terms, such as layer, seal, and the like, are for illustration only. More of these structures may be needed to effectively carry out this invention as disclosed.
[0029] Having thus described the preferred embodiments of the present invention, those of skill in the art will readily appreciate that the teachings found herein may be applied to yet other embodiments.
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A protective limb guard device for use in athletic or sporting activities is provided wherein the device comprises layers of conformable impact absorbing material that are formed to meet the shape of the user's limbs without the need for custom fitting. The limb guard of the present invention may include an inflatable tube instead of a layer of impact absorbing material.
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RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09/052,214 filed on Mar. 31, 1998, the entire teachings of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] Implantable medical prostheses, such as stents, are placed within the body to maintain and/or treat a body lumen that has been impaired or occluded, for example, by a tumor The stent can be formed of strands of material formed into a tube and are usually delivered into the body lumen using a catheter. The catheter carries the stent to the desired site and the stent is released from the catheter and expands to engage the inner surface of the lumen.
[0003] A self-expanding stent can be made of elastic materials. These are held in a compressed condition during catheter delivery by, for example, a sheath that covers the compressed stent. Upon reaching the desired site, the sheath constraining the stent is pulled proximally, while the stent is held in the desired position such that the stent expands.
[0004] There are both self-expanding and non-self-expanding stents. The self-expanding type of device is made with a material having an elastic restoring force, whereas a non-self-expanding stent is often made with elastic, plastically deformable material. It is positioned over a mechanical expander, such as a balloon, which can be inflated to force the prosthesis radially outward once the desired site is reached.
SUMMARY OF THE INVENTION
[0005] In a preferred embodiment, the invention features an implantable medical stent having a low profile during delivery. The stent is a tubular body with a body wall structure having a geometric pattern of cells defined by a series of elongated strands extending to regions of intersection. An example of a stent having a cell shape in accordance with the invention can be found in U.S. Pat. No. 5,800,519, which issued on Sep. 1, 1998, the entire contents of which is incorporated herein by reference. This stent cell structure utilized helically wrapped joints to connect the different strands to form a tubular body.
[0006] A limitation on the use of the helically joined stent involved the minimum constrained diameter of the stent during delivery. Because of the helically wrapped joints abutting one another along a given circumference, the minimum constrained diameter of the stent was 9 French (3 mm). For example, the length of the helically wrapped joint for a strand having a diameter of 0.006 inches (0.15 mm) in the constrained position is 0.045 inches (1.1 mm). For a five cell structure having five helically twisted abutting joints, this results in a constrained circumference of 0.228 inches (5.79 mm) with a diameter of 0.072 inches (1.8 mm). However, there are many applications in which it is necessary to achieve a smaller constrained diameter to provide delivery, for example, through smaller lumens within the vascular system, to reduce trauma during percutaneous delivery, or to provide endoscopic delivery through small diameter channels of endoscopes.
[0007] To achieve a smaller constrained diameter of 8 French or less, for example, a preferred embodiment of the invention replaces one or more of the helically wrapped joints along any given circumference with a simple crossed joint in which one strand crosses either above or below a second strand. Thus, the strands at a crossed joint can move more freely relative to each other, but this structure reduces the minimum circumference as the length of one or more helically twisted joints has been removed. This can reduce the constrained diameter by 50%.
[0008] In another preferred embodiment of the invention, the stent can include a first tubular body made from a first group of strands and a second tubular body surrounding the first tubular body and made from a second group of strands. This type of structure can be used to fabricate a low-profile device having sufficient radial expansion force for a self-expanding stent without a substantial change in foreshortening. This embodiment can include, for example, three or four helically wrapped joints along any circumference of the first and second tubular bodies in which the joints of the two bodies are offset in the constrained state. This embodiment also significantly improves the ratio of the expanded diameter to the constrained diameter.
[0009] The strands of the first group can have a different shape, diameter, or material from the strands of the second group such that the inner body has a larger radial restoring force than the outer body and can thereby impart the outward force to the outer body.
[0010] In one embodiment, the strands of the inner body can be thicker than the strands of the outer body and can be interleaved with the outer body along the entire length of the stent. In another preferred embodiment, the inner and outer bodies can be interlocked at one or both ends. This can permit the use of a cover between the inner and outer bodies along a certain portion of the stent. The use of the cover can enhance epithialization between the wall of the lumen and the outer body, reduce migration of the stent in certain applications and can prevent tumor in-growth. The cover can also provide a supporting matrix for drug delivery.
[0011] In one preferred embodiment, the strands of the stent are woven in a pattern with interlocking joints and skip joints as discussed above. In addition, the adjoining ends of the stent are aligned parallel to each other and laser-welded to secure the adjoining ends of the stent. The welded ends allow the stent to be compressed to a low profile.
[0012] In one preferred delivery system, the stent is positioned over an inner shaft and is covered by a composite sheath. The composite sheath can comprise a plurality of materials to provide a variable property such as a graded stiffness along the length of the sheath. In one embodiment the sheath can Include a braid or coil between outer and inner sheath layers to provide the longitudinal stiffness and flexibility needed for particular applications. The sheath can have at least a ten percent variation in stiffness along its length and as much as a fifty percent variation with the stiffer section at the proximal end and the least stiff section at the distal end. The sheath can extend coaxially about the inner shaft from the handle connected to the proximal end of the catheter and can be connected to an actuator that is manually operated by the user to slide the sheath relative to the inner shaft.
[0013] In one embodiment the inner shaft can include a braided tube, which extends from the proximal handle to a distal position of the delivery system. The inner shaft extends through a lumen of a catheter from the proximal handle to a distance short of the distal end where the catheter ends. The inner shaft can be free-floating within the lumen and receives the stent at the distal end. An outer sheath overlies the stent and the inner shaft and is moved to release the stent using a pull wire which is moved by the proximal handle using a conventional tooth strip attached to a pull wire.
[0014] In a preferred embodiment, the inner shaft is formed of steel braided tube encased in a polyimide. For low profile stent delivery systems, where the smaller diameter of the body lumen or the smaller diameter of the endoscope delivery channel necessitate improvements in the Push (or pull) strength of the catheter, the use of a braided tube to maintain flexibility and pushability without kinking provides effective delivery of low profile stents.
[0015] In the embodiments described above and in other embodiments, a mounting ring can be secured to the inner shaft or braided tube at the stent platform on which the stent is placed. The mounting ring has at least one radial member or ridge which projects towards the outer sheath. The ridge is located preferably at the proximal end of the stent. The ridges extend longitudinally, allowing the stent to be properly positioned while also allowing maximum compression of the stent for minimizing the diameter of the delivery system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.
[0017] [0017]FIG. 1A is a flat layout view along the longitudinal axis of a stent;
[0018] [0018]FIG. 1B is an enlarged portion of the stent taken at section 1 B- 1 B in FIG. 1A;
[0019] [0019]FIG. 2A is a perspective view of a stent according to the invention;
[0020] [0020]FIG. 2B is a flat layout view of an expanded low profile stent of FIG. 2A;
[0021] [0021]FIG. 3 is an enlarged cross-sectional view of a delivery tube containing a low profile diamond metal stent;
[0022] [0022]FIGS. 4A and 4B illustrate a mandrel for making a stent of FIGS. 2A, 2B, and 3 ;
[0023] [0023]FIG. 4C is a sectional view of the strands attached with a ball-welding;
[0024] [0024]FIG. 4D is a flat layout view of the joining ends of a low profile stent according to an alternative embodiment;
[0025] [0025]FIG. 4E is a perspective view of the strand of the stent in a laser welding apparatus;
[0026] [0026]FIG. 4F is a sectional view of the strands laser welded;
[0027] [0027]FIG. 5A is a distal end view of an endoscope;
[0028] [0028]FIG. 5B is a sectional view of the distal end of the endoscope;
[0029] [0029]FIG. 6A is an “over-the-wire” delivery system;
[0030] [0030]FIG. 6B is an enlarged view of the middle section of the “over-the-wire” delivery system;
[0031] [0031]FIG. 7 is a rapid exchange delivery system;
[0032] FIGS. 8 A- 8 E illustrate the operation of the delivery of the stent;
[0033] [0033]FIG. 9 is a flat layout view of a double layer stent;
[0034] [0034]FIG. 10 is a flat layout view of an alternative embodiment of a double layer stent;
[0035] [0035]FIG. 11 is an enlarged cross sectional view of the double layer stent of FIG. 10 with an interposed cover in an artery;
[0036] [0036]FIG. 12 is a cross sectional view of the double layer stent with the interposed cover taken along line 12 - 12 of FIG. 11;
[0037] [0037]FIG. 13 illustrates a mandrel for making a stent of FIGS. 9 or 10 and 11 ;
[0038] [0038]FIG. 14A is a perspective view of an alternative stent having six strands; and
[0039] [0039]FIG. 14B is a flat layout view of the stent of FIG. 14A.
[0040] [0040]FIG. 15A is a side view with portions broken away of an alternative embodiment of an “over-the-wire” delivery system;
[0041] [0041]FIG. 15B is an enlarged view of a middle section of an “over-the-wire” delivery system;
[0042] [0042]FIG. 15C is an enlarged view of the distal end of an “over-the-wire” delivery system;
[0043] [0043]FIG. 16A is a sectional view taken along the line 16 A- 16 A of FIG. 15B;
[0044] [0044]FIG. 16B is a sectional view taken along the line 16 B- 16 B of FIG. 15C;
[0045] [0045]FIG. 17A is a side view of a portion of the catheter showing a locking ring;
[0046] [0046]FIG. 17B is a sectional view taken along line 17 B- 17 B of FIG. 17A showing the interaction of the locking ring with the stent;
[0047] [0047]FIG. 17C is an illustration of a partially deployed stent with a locking ring;
[0048] [0048]FIG. 18 is a sectional view showing an alternative lock ring with the stent;
[0049] [0049]FIG. 19A is a side view, with portions broken away, of an alternative embodiment of an “over-the-wire” delivery system;
[0050] [0050]FIG. 19B is an enlarged view of the distal end of the “over-the-wire” delivery system of 19 A;
[0051] [0051]FIG. 20A is an enlarged view of the distal end of an alternative embodiment of an “over-the-wire” delivery system;
[0052] [0052]FIG. 20B is a similar view with the inner shaft removed;
[0053] [0053]FIG. 20C is a sectional view of the distal end of an “over-the-wire” delivery system; and
[0054] [0054]FIG. 21 is an enlarged view of an alternative embodiment of an “over-the-wire” delivery system;
[0055] [0055]FIG. 22A is a flat layout view along the longitudinal axis of a stent;
[0056] [0056]FIG. 22B is an enlarged portion of the stent taken at section 22 B- 22 B in FIG. 22A;
[0057] [0057]FIG. 23A is a flat layout view of another embodiment of the stent according to the invention;
[0058] [0058]FIG. 23B is a flat layout view of another embodiment of the stent according to the invention;
[0059] [0059]FIGS. 24A and 24B are oblique views of the nodes of a stent;
[0060] [0060]FIGS. 25A and 25B illustrate a mandrel for making a stent of FIGS. 22 A- 23 B;
[0061] [0061]FIG. 26A is an enlarged cross-sectional view of a delivery tube containing an alternative embodiment of a low profile diamond metal stent;
[0062] [0062]FIG. 26B is an enlarged portion of the stent taken at section 26 B- 26 B in FIG. 26A;
[0063] [0063]FIG. 27A is a side view of a coaxial delivery system with portions broken away; and
[0064] [0064]FIG. 27B is a sectional view taken along line 27 A- 27 A of FIG. 27A.
DETAILED DESCRIPTION OF THE INVENTION
[0065] Referring to the drawings in detail, where like numerals indicate like elements there is illustrated an implantable prosthesis in accordance with the present invention designated generally as 10 .
[0066] Medical prostheses, such as a stent 10 according to the invention, are placed within the body to treat a body lumen that has been impaired or occluded. Stents according to the invention are formed of wire configured into a tube and are usually delivered into the body lumen using a catheter The catheter carries the stent in a reduced-size form to the desired site. When the desired location is reached, the stent is released from the catheter and expanded so that it engages the lumen wall as explained below.
[0067] A stent 20 is shown in a flat layout view in FIG. 1A. The stent 20 is formed of elongated strands 22 such as elastic metal wires. The wires 22 are woven to form a pattern of geometric cells 24 . The sides 26 a, 26 b, 26 c, and 26 d of each of the cells 24 are defined by a series of strand lengths 28 a, 28 b, 28 c, and 28 d. Each of the sides 26 are joined to the adjoining side at an intersection where the strands 22 are helically wrapped about each other to form interlocking joints 30 .
[0068] Referring to FIGS. 1A and 1B, the interlocking joints 30 are loose and spaced from each other in the full expansion position. The cells 24 have a diamond shape. The strand angle is α. When the stent 20 is racially compressed, in certain instances, the interlocking joints 30 are in tight interference such that points 32 and 34 are in close proximity. In other Instances, the interlocking joints 30 separate. In addition, the interlocking joints 30 on the same circumference are in close contact, therefore establishing the compressed, reduced size which can be fit within a sleeve for delivery on a catheter. A medical prosthetic stent and method of manufacturing such a stent is described in U.S. patent application Ser. No. 08/743,395 which issued as U.S. Pat. No. 5,800,519 on Sep. 1, 1998 and which is incorporated herewith by reference.
[0069] Referring to FIG. 2A, an isometric view of stent 10 according to the invention is shown in an expanded position. The stent 10 is formed from a plurality of strands 42 . In a preferred embodiment, there are five strands 42 , as seen in the layout view of FIG. 2B. The strands 42 are woven in a pattern starting at a proximal end 44 . The pattern forms a plurality of geometric cells 46 . Each strand 42 forms a pair of sides 48 a and 48 b of the most distal cell 46 . Each of the sides, with the exception of at least one as explained below, are joined to the adjoining side at an intersection 52 where the strands 42 are helically wrapped about each other to form interlocking joints 54 .
[0070] While there are five intersections 52 , at least one of the intersections 52 is formed by strands 42 that cross forming a cross joint and are not twisted to form a wrap as indicated at point 56 in FIG. 2B. A preferred pattern of where the strands 42 just cross is spaced 1-½ cells 46 away, as seen in FIG. 2B.
[0071] The strand angle α is increased in the compressed or constrained state of the stent in this embodiment. The strand angle can he in the range of 10°-80° depending upon the particular embodiment. Smaller strand angles between 10° and 45° often require a shortened cell side length L to maintain radial expansion force. Cell side lengths L in the range of 0.5 to 4 mm, for example, can be used with stent having these smaller strand angles. For stents with larger strand angles in the range of 3-8 mm can be used, depending on the expanded diameter of the stent, the number of cells and the desired radial expansion force.
[0072] Referring to FIG. 3 the stent 10 is shown in the contracted position within the sleeve 58 . Similar to the embodiment shown in FIGS. 1A and 1B, the size to which the stent 10 can be constricted is limited by where the interlocking joints 54 engage each other. The elimination of one wrap joint allows for the stent 10 to be compressed to a smaller size.
[0073] In a preferred embodiment, the strands 42 are formed of nitinol wire. The wires each have a diameter of 0.006 inches (0.15 mm) The diameter of the wires can vary depending on the number of cells and desired properties and generally in preferred embodiments range from 0.004 inches (0.10 mm) to 0.006 inches (0.15 mm). The stent 10 has an outside diameter when fully expanded of 10 millimeters. The stent 10 is capable of compressing into a sleeve 58 of an outside diameter of 8.0 French or less, and preferably 7.0 French (3 fr=1 mm). The stent shown in the FIGS. 1A and 1B, of similar material and dimension, is capable of compressing to a diameter of approximately 9 fr.
[0074] In one preferred embodiment, the length of the legs or sides 48 of the cells 46 is similar to that of the embodiment shown in FIGS. 1A and 1B. The radial force is decreased from the elimination of one of the interlocking or wrap joints. The compressed stent 10 has a length of approximately 120 percent or less relative to the expanded stent. Therefore, for a 10 centimeter stent, the compressed length is 12 centimeters or less.
[0075] In one preferred embodiment, the length of the legs or sides 48 of the cells 46 are reduced. The reduced length provides radial force and compensates for decreased radial force resulting from the elimination of one of the interlocking or wrap joints. In an alternative embodiment, the radial expansion force increased by varying the anneal cycle of the stent.
[0076] The varying of the length of legs or sides 48 of the cell or the change in the angle α can effect foreshortening. While it is preferred to have foreshortening of 120 percent or less, in certain embodiments it may be desirable to have greater foreshortening, such as the compressed stent 10 has a length of approximately 150 percent of the expanded stent.
[0077] In one preferred embodiment, a plurality of (ten shown) platinum-iridium radiopaque (R.O.) markers 60 are located on the stent 10 . The R.O. markers 60 are threaded onto the terminating cells; five on the proximal end and five on the distal end.
[0078] A mandrel 62 for making the stent is shown in FIGS. 4A and 4B. The mandrel 62 has a plurality of pins 64 on the outer surface of the mandrel in a pattern that determines the geometric cell 46 pattern. The strands 42 are bent around the top portion 66 of each top anchoring pin 64 to form the proximal end 44 of the stent 10 . The strands 42 are then pulled diagonally downward to an adjacent anchoring pin 64 where the strands 42 are joined. The strands 42 are helically wrapped about each other to form the interlocking joint 54 , with each strand passing through a single 360 degree rotation. The two strands are pulled taught so that the interlocking joint 54 rests firmly against the bottom portion 68 of the anchoring pin 64 such that each strand 42 is maintained in tension.
[0079] Each level of anchoring pins 64 is missing a pin 64 in a set order, such as to achieve the desired pattern in FIG. 2B. The stands 42 which pass the missing pin location simply cross to form the cross joint.
[0080] In a preferred embodiment, the anchoring pins 64 are square. The square pins retain the helically wrap of the strands in a proper position. In a preferred embodiment, the pins have a width of 1 millimeter. The anchoring pins can have a smaller width such as 0.5 mm for use with narrower diameter strands, such as 0.005 inch diameter strands.
[0081] The free ends of the strands 42 are then pulled downward to the next diagonally adjacent anchoring pin 64 . This process is continued until the desired length of the stent 10 is achieved.
[0082] The stent 10 is then heat-treated. The strands 42 at the joining end 40 of the stent 10 are welded using a ball-welding technique. The strands 42 are twisted around each other for several twists of the strands as best seen in FIG. 2B. The strands having a diameter of 0.006 inches (0.15 mm) will form a diameter of 0.012 inches as seen in FIG. 4C. In addition, the ball-weld creates a weld ball 250 having a diameter of 0.018 inches (0.46 mm) to 0.020 inches (0.51 mm). Upon compression of the stent, the weld balls 250 may engage each other limiting the compression of the stent. The stent with these diameters can fit within an outer sheath having a 7 French inner diameter. The heat-treating and alternative finishing techniques are described in U.S. Pat. No. 5,800,519 on Sep. 1,1998, the entire contents is incorporated herein by reference.
[0083] A layout view of the distal end of the stent 10 is shown in FIG. 4D. The strands 42 of the stent 10 are woven in a pattern as discussed above with respect to FIGS. 4A and 4B. The joining ends 40 of the stent 10 are aligned parallel to each other to form the end of the most distal cells 46 . The joining ends 40 of the strands 42 are held together by a pair of holding straps 268 onto a surface 270 as seen in FIG. 4E. A laser welder 272 moves along the joint 274 of the two adjoining strands 42 . A plurality of energy pulses are directed at the joint 274 as the laser welder 272 moves along the joint. After completing this initial weld, the laser welder 272 is moved back to a position 280 , to achieve a finished length and a higher energy pulse is directed at the point or position mark by dotted line 280 to cut the strands 42 .
[0084] In a preferred embodiment, a 400 micron fiber is used with a spot size having a diameter of 3.9 to 4.1 millimeters. In one example, twenty pulses of energy are directed at the joint 274 as the laser welder 272 moves a distance of 1.3 millimeters (+/−0.5 mm). Each pulse has an energy level of 145 millijoules (+/−10 millijoules) and a duration of 0.1 milliseconds. The single higher energy pulse of one joule, and a duration of 2 milliseconds cuts the strands.
[0085] Referring to FIG. 4F, an example of the cross-section of the strands 42 using the laser weld technique described above is shown. The laser welding forms a fill 276 on the top and a cut-off fill 278 on the bottom. The overall diameter of the strands 42 and weld is 0.012 inches (0.3 mm) therein for a five wire system the compression size is 4.57 French. Therein, a stent with the laser welded ends can compress to a smaller diameter than those with the ball welds.
[0086] Another alternative to the R.O. markers 60 for locating the stent 10 using fluroscopy is to coat the stent with gold. The stent 10 can be either totally or partially coated. In a partially coated stent, only portions of the strands between the joints are coated. Coating of a stent is described in further detail in U.S. Pat. No. 5,201,901 which issued on Apr. 13, 1993, the entire contents is incorporated herein by reference. A clad composite stent is described in U.S. Pat. No. 5,630,840 which issued on May 20, 1997, the entire contents being incorporated herein by reference. A further embodiment of the invention utilizes a stent having a core as described in U.S. Pat. No. 5,725,570 which issued on Mar. 10, 1998, the entire contents is incorporated herein by reference.
[0087] In one preferred embodiment, the stent 10 is installed using an endoscope 70 as seen in FIGS. 5A and 5B. The endoscope 70 has a channel 72 which is typically used for collecting biopsy samples or for suction. The stent 10 is passed through the channel 72 into the body as explained below. The endoscope 70 in addition has an air/water nozzle 74 for cleaning the area in front of the endoscope 70 . In addition, the endoscope 70 has a mechanism for the physician to see what is in front of the endoscope 70 ; this mechanism includes an objective lens 76 . A pair of illumination lenses 78 which are used in lighting the site are also shown.
[0088] [0088]FIG. 5B illustrates a cross sectional view of the distal end of the endoscope 70 . An air/water tube 80 extends down to the air/water nozzle 74 . Both the viewing mechanism and the illumination mechanism have optical fiber bundles 82 leading to the respective lens 76 and 78
[0089] Endoscopes come in various sizes and lengths depending on the purpose. The channel 72 likewise has different sizes. It is recognized that it may be desirable to use a smaller diameter scope to be less invasive or that a larger diameter scope will not fit the lumen. The following table is an example of various size endoscopes.
Working Length Distal Tip Channel (cm) O.D. (mm) Diameter (mm) 55 4.8 2.0 55 6.0 2.6 63 12.2 3.2 102 9.8 2.8 102 12.6 3.7 124 11.0 2.8 124 11.0 3.2 125 11.3 4.2 173 13.0 3.2
[0090] In a preferred embodiment, with the dimensions given above, the stent 10 as described in relation to FIGS. 2 A- 4 B can be used with channels of 3.2 mm or greater as described below. It is recognized that with other dimensions of the stent and/or laser weld of the ends, the stent catheter can fit in a smaller diameter channels such as 2.6 mm or 2.0 mm. For a 2.6 mm endoscope channel, a 2.3 mm outer shaft or catheter diameter is employed.
[0091] In addition, the stent 10 can be introduced using a percutaneous insertion. In both the method using the endoscope 70 and the percutaneous procedure, an over the wire delivery system 86 as seen in FIG. 6A can be used. The over-the-wire delivery system 86 has an elongated catheter on inner shift 88 over which the stent 10 is positioned. The catheter 88 extends from a proximal handle 90 to a distal tip end 92 . The catheter 88 extends through an outer shaft 94 at the proximal end.
[0092] An outer sheath 98 is located at the distal end of the over the wire delivery system 86 . The outer sheath 93 is moved towards the handle 90 using a pull wire 102 and a pull ring 104 as seen in FIG. 6B. A guidewire 103 extends through the catheter to the distal end tip 92 , as best seen in FIG. 6A.
[0093] In a preferred embodiment, the outer sheath 98 has an outer diameter in the range of between 0.072 inches (1.8 mm) and 0.094 inches (2.4 mm). The inner diameter of the outer sheath 98 has a range of between 0.066 inches (1.7 mm) and 0.086 (2.2 mm)inches. The outer sheath tends to the lower portion of the range when the stent can contract to the 6 French size and towards the upper portion of the range when the stent can contract to the 7 French size.
[0094] In one preferred embodiment, the outer sheath 98 is formed having several layers of material. The nominal outer diameter is 0.093 inches and a nominal inner diameter of between 0.078 and 0.081 inches. The inner layer is composed of polyethylene or TFE and has a nominal thickness of 0.001 inches. A layer of EVA or polyurethane of a nominal thickness of 0.0005 inches forms the second layer. A braid metal spring stainless or liquid crystal polymer (LCP) fiber having a thickness of 0.0015 to 0.0025 inches overlies the second layer and forms the core of the outer sheath 98 .
[0095] In a preferred embodiment, the fourth layer varies in material composition as it extends from the proximal end to the distal end. The proximal end of the sheath is formed of Pebax or polyamide and the material varies to a polyamide or cristamid at the distal end. This layer has a nominal thickness of 0.002 inches. This varying of the material is for increased flexibility at the distal end to move through tortures easier and increased rigidity at the proximal end to give the catheter better push.
[0096] The sheath 98 has a finish layer of a hydrophlic coating having a thickness of between 0.0005 and 0.001 inches. The coating is for increase lubricativity.
[0097] The shaft has an outer diameter of 0.074 inches (1.88 mm) The shaft is formed of nylon 12 , cristamid, or cristamid.
[0098] In a preferred embodiment, the tip extrusion has an outer diameter in the range of between 0.042 and 0.055 inches. The inner diameter of the tip extrusion has a range of between 0.036 and 0.040 inches.
[0099] In one preferred embodiment, the tip extrusion or catheter has a nominal outer diameter of 0.047 inches and an inner diameter of 0.037 inches. The inner diameter defines the passage for he guidewire. In a preferred embodiment, the catheter is formed of Peek (Polyether ether ether Keetone) Peek Braid Peek, Polyimide or Polyimide Braid Polyimide. In a preferred embodiment, the guide wire 108 has a diameter of 0.035 inches. It is recognized that the guide wire can be larger or smaller as indicated below.
[0100] An alternative method to the over-the-wire delivery system 86 shown in FIGS. 6A and 6B is a rapid exchange delivery system 112 shown in S 7 . The rapid exchange delivery system 112 has a shaft 114 that extends from a proximal handle 116 . A guidewire 118 extends from a two lumen transition zone 120 through an outer sheath 122 to a distal tip end 124 . In Contrast to the over the wire delivery system 86 , the guide wire 118 does not extend all the way back to the proximal handle 116 . Similar to the over the wire delivery system 86 , the outer sheath 122 of the rapid exchange delivery system 112 is moved towards the handle 116 using a pull wire 128 and a pull ring 130 .
[0101] Referring to FIGS. 8 A- 8 F, the over-the-wire delivery system 86 of FIGS. 6A and 6B is shown for positioning a stent 10 in a bile duct. Stents are used in many uses including for treatment of an obstruction 134 , such as a tumor in the bile duct. The delivery system can position a prosthesis, such as a stent 10 , to move the obstruction out of the lumen 136 .
[0102] Typically, the occlusion substantially closes off a lumen, such as a bile duct which has a healthy diameter of about 8-10 mm. The obstruction may be several centimeters in length. After the obstruction is located using one of several diagnostic techniques, the physician gains access to the lumen. Using ultrasound or fluoroscopy, the guidewire 108 such as seen in FIG. 8C, is positioned through the outer access sheath 98 so that it extends past the obstruction.
[0103] Referring to FIG. 6A, the delivery system 86 is advanced axially and distally until the distal radiopaque marker 60 is positioned axially at a location at least about 1 cm distal of the occlusion 134 . This location substantially corresponds to the position at which the distal end 47 of the stent 10 , when expanded, will engage the lumen wall 136 . The location is selected so the stent 10 is positioned beyond the occlusion 134 but not too close to the end of the bile duct, for example. The marker 138 indicates the position of the proximal end 40 of the stent 10 in the expanded position and is such that the proximal end 40 of the prosthesis will engage healthy tissue over a length of at least 1 cm. Where possible the stent 10 is centered about the obstruction, based on the fully expanded length indicated by markers 138 and 140 . The marker 139 indicates the proximal end of the stent when the stent is in the fully compact form, which has an overall length of approximately 20 percent longer than in its expanded state. Therefore for a stent of 7.5 centimeters, the compressed state has a length of approximately 9 centimeters.
[0104] The sheath 98 is retracted in one continuous motion as illustrated in FIG. 8B. With the sheath 98 partially withdrawn, (arrow 144 ), portions of the stent 10 expand (arrow 146 ) The lengthening of the stent 10 has a simultaneous effect of reducing the radial force the stent exerts on the wall of the sheath 98 and, therefore, reducing the frictional force between the inner wall of the sheath and the stent 10 , allowing a smoother retraction of the sheath 98 with less axial force.
[0105] After sheath retraction continues but usually to a point less than the marker 138 , the proximal end 40 of the expanding and contracting prosthesis 10 exits the sheath 98 and engages the lumen wall 136 , forcing open the lumen 136 to its normal diameter and firmly anchoring the stent so that it resists axial motion, as illustrated in FIG. 8C.
[0106] The stent is released entirely from the catheter body 88 by drawing the catheter body 88 proximally (arrow 152 ) as seen in FIG. 8D, which causes the end loops to be positioned at more distal positions along the members, until the radial force of the stent 10 causes the members to deflect outwardly (arrows 154 ).
[0107] The catheter 88 is then removed from the body, leaving the prosthesis 10 properly positioned as Illustrated in FIG. 8E.
[0108] An alternative embodiment of the low profile diamond stent is shown as a flat layout view in FIG. 9. The stent 160 has two separate layers 162 and 164 ; an inner layer 162 shown in hidden line and an outer layer 164 . Each layer 162 and 164 of the stent 160 has a plurality of strands 166 . In a preferred embodiment, each layer has four strands; this is in contrast to the five strands in the previous embodiment. While four and five strand embodiments are shown above, it is recognized that the number of strands and cells can vary, for example, from three to ten or higher, dependent on size, type of joint or the strands, use and other factors.
[0109] The strands are woven in a pattern of geometric cells 169 starting at the distal end 170 . Each strand 166 forms a pair of legs 144 of the most distal opening on the cell 168 . The inner layer 162 and the outer layer 164 are intertwined at both the distal end 170 and the proximal end 172 .
[0110] The sides 176 a, 176 b, 176 c, and 176 d of each of the cells 168 are defined by a series of strand lengths 178 a, 178 b, 178 c, and 178 d. Each of the sides 176 are joined to this adjoining side at an intersection where the strands are helically wrapped about each other to form interlocking joints 180 .
[0111] Similar to the embodiment shown in FIGS. 1A and 1B and in contrast to the previous embodiment, every intersection has an interlocking joint 180 . Without the fifth strand 166 , the stent 160 can be contracted into a smaller diameter than that of the stent 20 shown in FIGS. 1A and 1B.
[0112] In a preferred embodiment for use in a colon, both layers are formed of identical materials. Each strand is composed of nitinol and has a diameter of 0.010 inches (0.25 mm).
[0113] Still referring to FIG. 9, the two separate layers 162 and 164 in the constricted position are off-set from each other so the interlocking joints of one layer do not engage with the interlocking joints of the other layer. The off-set between layers can be created by either an off-set during manufacturing as described below, or created by the related motion of the layers as the layers are constricted. The related motion can be the result of the constraints of the strands or the material properties. One property difference can be the thickness of the strands as described in the next embodiment.
[0114] The stent can be coated with a silicon lubricant or suitable lubricant to ease the self-expanding of the stent.
[0115] An alternative embodiment of the double layer stent 160 of FIG. 9 is shown in FIGS. 10 - 12 . In contrast to the double layer stent 160 of FIG. 9, the double layer stent 188 has a cover layer 190 interposed between an outer layer 192 and an inner layer 194 . The outer layer 192 is shown in hidden line and the cover layer 190 is shown in hidden line in FIG. 10. It is recognized that the cover layer 190 can be placed in other locations.
[0116] Similar to the previous embodiment, the inner layer 194 and the outer layer 192 are intertwined at both the proximal end 170 and the distal end 172 . The intertwining of the layers 192 and 194 retains the cover layer 190 in position.
[0117] In a preferred embodiment, each layer has four strands and are woven similar to the embodiment shown in FIG. 8 to define the geometric cells 198 . The strands of the two layers are formed of two different thickness wires in a preferred embodiment. The inner layer has a thicker wire.
[0118] [0118]FIG. 11 shows the sent in an artery. The stent is moving an obstacle out of the passage. The cover prevents tumor in-growth, will seal fistulas and block aneurysms.
[0119] One technique for placing a stent into the circulation system of a patient is to enter from the brachial artery located in the arm. This point of entry can be used for insertion into the vascular system including for example, peripheral locations such as the knee which require the flexibility of the diamond stent.
[0120] A cross-sectional view of the stent 188 is shown in FIG. 12. The inner layer 194 having the thicker strands forces the cover 190 and the outer layer 192 outward. The cover 190 is in engagement with both the inner layer 194 and the outer layer 192 .
[0121] In a preferred embodiment, the strands are formed of nitinol. The inner layer has strands having a diameter of 0.006 inches (0.15 mm). The strands of the outer layer have a diameter of 0.005 inches (0.13 mm). The radial expansion force of the thicker wire inner layer is transmitted to the outer layer. The radial expansion force can be altered by varying one or both layers.
[0122] In another preferred embodiment, the stent has three strands on each layer. The inner layer has a diameter of 0.008 inches (0.02 mm). The strands of the outer layer have a diameter of 0.005 (0.13 mm) inches.
[0123] The outer layer can be formed from a non self-expanding material. The outer layer can be chosen for its radiopaque characteristics. Materials that can be chosen for their radiopacity characteristics include tantalum, platinum, gold or other heavy atomic metal.
[0124] In a preferred embodiment, a cover is interposed between the layers. The cover can be made of several types of material which allow the stent to be compressed to a small diameter and also be self-expanding. A preferred material is a woven carbon fiber, a metal mesh, a polymer such as a polyurethane, or a material treated with a drug for time release. Different agents can be employed on the inside and the outside. An electrical current can be applied to tissue using the stent. Different materials for the layers can be used than the interposed cover depending on the treatment site and the desired method of treatment.
[0125] In one preferred embodiment, the layers 192 and 194 are interwoven for the entire stent without an interposed cover. Referring to FIG. 13, a mandrel 262 has a plurality of anchoring pins 264 . For a stent having two layers of four strands each, each row has eight (8) anchoring pins 264 at the same height. The top row, however, has the anchoring pins 264 for one strand positioned ½ millimeter higher than the other set. After the stent is woven, the distal end of each stent is pulled to the same position, therein resulting in the rest of the interlocking joints being offset.
[0126] If there is no cover between the two layers, the two layers can be interwoven from the distal end to the proximal end.
[0127] [0127]FIGS. 14A and 14B illustrate a single layer stent 210 having six strands. The stent 210 has four wrap joints 254 a pair of cross joints 256 .
[0128] In one preferred embodiment, the stent 210 has a diameter of 14 millimeters in the expanded state. The stent has foreshortening in the range of 12 to 18 percent. With the strands having a diameter of 0.006 inches (0.15 mm), the stent with only four wrap joints 254 per row can compress to fit within a 7 French system.
[0129] An alternative delivery system 286 is illustrated in FIG. 15A. The stent 10 is positioned over an inner shaft 288 , which is a braided tube, at a distal end 289 of the delivery system 286 . The inner shaft 288 extends to a proximal handle 290 . The delivery system 286 has an outer shaft 292 which extends from the proximal handle 290 to a point 294 , which is proximal the distal end 289 . The inner shaft 288 extends through a lumen 296 of the outer shaft 292 from the proximal handle 290 and projects out at the distal end of the outer shaft 292 . The inner shaft 288 secured to a luer fitting 298 housed in the proximal handle 290 , also referred to as an actuator housing or gun portion, of the delivery system 286 . The inner shaft 288 is free-floating with the lumen 296 .
[0130] An outer sheath 300 overlies the inner shaft 288 and the outer shaft 292 from the distal end 289 of the inner shaft to a point 302 of the delivery system 286 . The outer sheath 300 is movable relative to the inner shaft 288 and the outer shaft 292 and is pulled from the distal end 289 of the inner shaft 288 using a pull wire 304 which extends in a second lumen 306 of the outer shaft 292 . The distal end of the second lumen 306 is proximal to the distal end of the lumen 296 . The outer sheath 300 and the pull wire 304 are pulled using an actuator 308 of the delivery system 286 . The pull wire 304 is attached to a toothed strip 310 that engages the actuator 308 . A guidewire 312 extends through the inner shaft 288 from the proximal handle 290 to the distal end 289 .
[0131] In a preferred embodiment, the outer shaft 292 ends between 1.8 and 20.0 centimeters before the distal end 289 . The outer sheath 300 extends from the distal end 289 , in the range of 1 to 50 centimeters towards the proximal handle.
[0132] Referring to FIG. 15B, an enlarged view of the delivery system where the inner shaft 288 extending from the outer shaft 292 is shown in FIG. 15A. The inner shaft 288 is shown projecting from the lumen 296 of the outer shaft 292 . The outer shaft 292 narrows at its distal end to minimize large discontinuities of material. The pull wire 304 is above the outer shaft 292 and can extend around the inner shaft 288 . The pull wire 304 is carried by the second lumen 306 of the outer shaft 292 to a point lust proximal to this location. The pull wire 304 extends down and is connected to the sheath 300 by a pull ring 305 . The pull ring 305 in a preferred embodiment is sintered to the outer sheath 300 . The inner shaft 288 is free to move within the lumen 296 of the outer shaft 292 at this point.
[0133] The distal end 289 of the delivery system 286 is shown enlarged in FIG. 15C. At the end of the inner shaft 288 there is located a distal tip 318 . In a preferred embodiment, the tip is formed of a polymer which has been molded onto the inner shaft 288 . Overlying the inner shaft 288 is the stent 10 . The stent 10 is positioned by a reference locator/stop 321 . The outer sheath 300 overlies the inner shaft 288 and the stent 10 , and engages the distal tip 318 . A pair of radiopaque markers 328 are shown encircling the inner shaft 288 .
[0134] Referring to FIG. 16A, a sectional view of the inner shaft 288 projecting from the lumen 296 of the outer shaft 292 is shown. The outer sheath 300 can be formed of various biocompatible polymers such as a polyamide with a center core of liquid crystal polymer (LCP). It is recognized that the outer sheath 300 can be formed of other compositions as discussed above and below in alternative embodiments. In a preferred embodiment, the outer sheath 300 has an outside diameter of 4-7 French. The wall thickness is typically 0.003 to 0.005 inches (0.076 mm to 0.13 mm).
[0135] The outer shaft 292 has an outer diameter of 0.066 inches (1.7 mm), which allows the proximal end of the outer shaft 292 to fit within the outer sheath 300 . The outer shaft 292 in a preferred embodiment is made of polyamide or nylon, but can alternatively be made of other biocompatible polymers such as polyester, polyurethane, PVC or polypropylene. The lumen 296 of the outer shaft 292 has a diameter of 0.035 to 0.037 inches (0.89 to 0.94 mm), for example, and receives the inner shaft 288 . The outer shaft 292 in a preferred embodiment has a plurality of other lumens including the second lumen 306 which the pull wire 304 extends through. In a preferred embodiment, the second laden 306 has a diameter of slightly larger than the pull wire 304 . The pull wire 304 is typically a single stainless steel wire having a diameter of 0.012 inches (0.30 mm). However, the pull wire 304 can consist of a plurality of wires and can be formed of a different material.
[0136] The inner shaft 288 is formed of a reinforced layer encased by an outer layer and an inner layer. In a preferred embodiment, the inner shaft 288 has as a center reinforcement layer comprising of a tubular woven steel braid 320 . The reinforcement layer is encased by the inner and outer layer of polyimide 322 . The tubular woven steel braid is formed of flat strands 324 having a thickness of 0.0015 to 0.003 inches (0.038 mm to 0.076 mm) and a width of 0.001 to 0.005 inches (0.025 to 0.13 mm) in a preferred embodiment. The inner diameter of the tubular woven steel braid is 0.015 to 0.038 inches (0.38 mm to 0.97 mm). The tubular steel braid is encased in the polyimide such that in a preferred embodiment the outer diameter of the inner shaft 288 0.021 to 0.041 inches (0.53 to 1.0 mm). The thickness of the wall of the inner shaft is typically between 0.003 to 0.008 inches.
[0137] Within the single braided polymer tube 288 a guidewire 326 may extend as seen in FIG. 16A. The guidewire 326 in a preferred embodiment is formed of stainless steel. The guidewire 326 in a preferred embodiment has a diameter in the range of 0.014 to 0.037 inches (0.36 to 0.94 mm) and in a preferred embodiment 0.035 inches (0.89 mm).
[0138] Referring to FIG. 16B, a sectional view of the distal end of the delivery system is shown. The sheath 300 is overlying the inner shaft 288 with the stent 10 being interposed. The pull wire 304 seen in FIG. 16A is secured to the sheath at a position proximal to that shown in FIG. 16B.
[0139] The delivery system 286 can be used in numerous ways. One such way is by placing the delivery system's outer shaft 292 and inner shaft 288 through an endoscope 70 such as shown in FIGS. 5A and 5B. Alternatively, a percutaneous procedure can be used. In both procedures, the guidewire extending through the inner shaft 288 is extended beyond the inner shaft 288 and used to define the path. The inner shaft 288 is to be pushed a short distance along the guidewire. The guidewire and inner shaft 288 are moved until the distal tip is in position.
[0140] The inner shaft 288 has sufficient strength that it is able to follow the guide wire and resist kinking Overlying the inner shaft 288 is the outer sheath 300 which gains its structural strength by engaging and forming a continuous structure with the distal tip 318 of the inner shaft. The sheath 300 is pulled in the proximal direction to expose the stent 10 as explained above and therefore does not have to slide over the distal tip 318 of the inner shaft 288 .
[0141] The stent 10 is located between the outer sheath 300 and the inner shaft 288 . The inner shaft 288 is secured only at the luer fitting 298 housing the proximal handle 290 of the delivery system 286 . The inner shaft 288 floats freely and is not otherwise secured within the lumen 296 of the outer shaft 292 .
[0142] When the distal tip is in the proper position in the artery, vessel or other desired location, the outer sheath 300 is pulled proximally by using the handle on the proximal handle 290 which engages an actuator 308 that moves the tooth strip 310 . The tooth strip 310 is connected to the pull wire 304 which extends through a lumen in the outer outer shaft to a point beyond the proximal end of the outer sheath and the pull wire extends from that point to the pull ring. With the outer sheath moved proximally, the stent 10 is able to self expand into proper position.
[0143] Referring to FIGS. 17A and 17B, an alternative embodiment of a delivery system 330 is shown. The delivery system inner shaft 332 which is encircled by an inner ring 338 of a mounting ring 334 . The mounting ring 334 has at least one radial member or ridge 336 , which projects radially out from the inner ring 338 towards the outer sheath 300 In a preferred embodiment, the ring 334 has a pair of ridges 336 which project radially outward in opposite directions along a common axis, or in other words, at an angular separation of 180 degrees. Additional ridges 336 that can be evenly spaced around the circumference of the ring 334 to evenly distribute the load force on the stent and can extend longitudinally between 1 and 8 mm such that the proximal loops at one end of the stent grasp the ridges during mounting. The stent is then held in place by the outer sheath during delivery and release. For example, three members 336 are spaced 120 degrees apart round 334 .
[0144] Cells of the stent 10 are placed around the protrusions 336 . With the strands 42 of the stent 10 encircling the tabs 336 , the stent 10 can compress while still being retained. Placement of the members at the proximal end of the stent 10 affords maximum extension and compression of the stent to within the needed diameters.
[0145] An alternative method uses a solid mounting ring where the stent is held with a friction fit between the outer sheath and the ring to retain the stent in position in the delivery system The solid ring with the friction fit is further described in U.S. Pat. No. 5,702,418 which issued on Dec. 30, 1997, the entire contents of which is incorporated herewith by reference.
[0146] Alternatively, as seen in FIG. 17C, the tabs or ridges 336 of the ring 334 retain the stent 10 as the stent 10 is deployed. If it is determined prior to the stent 10 being totally deployed that the stent is not in proper position, the stent can be retracted back into the delivery system.
[0147] In a preferred embodiment, the inner ring 334 has an outer diameter of 0.05 inches (1.3 mm) The tabs 336 project such that the distance from the radial end of one tab 336 to the radial end of a tab on the other side of 0.07 inches. The tabs have a width of 0.01 inches. The ring 334 can have a length of 0.06 inches.
[0148] [0148]FIG. 18 shows an alternative mounting ring 335 . The ring 335 is a solid ring with sections removed to define a plurality of grooves 337 . The grooves 337 receive the strands of the stent 10 , with the projections or ridges 339 located in the cells of the stent 10 .
[0149] Similar to the previous “over-the-wire” delivery system shown, an “over-the-wire” delivery system 340 shown in FIG. 19A has an inner shaft 342 extending from a proximal handle 344 to a distal tip end 346 . The inner shaft 342 extends through an outer shaft 350 at the proximal end. An outer sheath 352 is located at the distal end of the “over-the-wire” delivery system 340 , overlying the exposed inner shaft 342 and a portion of the outer shaft 350 . The outer sheath 352 is moved toward the handle using a pull wire 354 and a pull ring 356 . The pull wire 354 extends through a lumen 348 of the outer shaft 350 from the proximal handle 344 to a point just proximal to where the inner shaft 342 extends from the outer shaft 350 .
[0150] Referring to FIG. 19B, the outer sheath 352 is formed of several layers of material. An inner layer 360 can be formed of a nylon 12 which extends the entire length of the outer sheath 352 . Overlying the inner layer 360 is a braid 362 of either a metallic or fiberglass such as a stainless steel braid. The outer sheath 352 has an outer layer 364 formed of nylon 12 extending from the proximal end to a position proximal and adjacent to the distal end 346 . The last portion of the outer layer 364 is formed of another material which is less stiff, or softer, such as a PEBAX.
[0151] In a preferred embodiment, the last portion of the outer sheath 352 which has the less stiff or softer material on the outer layer 364 , extends 36 centimeter (+/−one cm) and the entire length of the outer sheath is approximately 200 cm. In a preferred embodiment, the outer diameter of the sheath is 0.920 inches (+/−0.001 inches, or about 23.4 millimeters) with the wall thickness being 0.0070 inches (+/−0.0005 inches) (0.1778 millimeter +/−0.0127 millimeter). The braid 362 is formed of a stainless steel having a diameter of 0.0015 inches (0.038 millimeter).
[0152] It is noted that the delivery systems shown can be used in various locations such as non-vascular systems and vascular systems. In the embodiment shown above, one of the application is endoscopic delivery in the gastric system which requires that the deliver, system be capable of taking a 90 degree bend. The inner shaft, sometimes referred to as the catheter, has an outer diameter that approximates the inner diameter of the outer sheath, for a segment near the distal end, just proximal to where the stent is positioned, as seen in FIG. 19B. This is in contrast to the embodiment shown in FIG. 16B.
[0153] An alternative embodiment of an “over-the-wire” delivery system 370 is shown in FIGS. 20A and 20B. The delivery system 370 has an inner shaft 372 seen from the proximal handle 374 to a distal tip end 376 . The inner shaft 372 extends through an outer shaft 380 at the proximal end. An outer sheath 382 is located at the distal end of the “over-the-wire” delivery system 370 .
[0154] This embodiment has the same elements as the previous embodiment. The outer sheath 382 has variable properties as explained below. As indicated above, it is recognized that the path the delivery system takes is almost never straight and usually has many bends between the insertion point into the body and the stricture or stent delivery site. In order to reach the delivery site, the delivery system including the outer sheath 382 must be flexible enough to negotiate the bends, but have sufficient strength and stiffness.
[0155] The outer sheath 382 is formed of a plurality of layers. An inner layer 390 is formed of a fluorinated polymer such as PTFE or FEP, or polymer such as HDPE. A second layer 392 encases the first layer and consists of a polyurethane such as those sold underneath the name TECOFLEX™ or PLEXAR™. A third layer 394 consists of a polymer braiding, such as LCP fiber (Vectran), or a metal braided coil. In a preferred embodiment, the braiding is flat. However, it is recognized that a round braiding may also be used. A fourth layer 398 , an outer layer, of the outer sheath 382 material properties vary as it goes from the proximal end to the distal end.
[0156] In a preferred embodiment, the properties of this fourth layer 398 are divided into two materials and a combination of these materials in the transition. For example, the first portion is a material/blend chosen for higher density, crush strength, relative high durometer and stiffness such as a polyamide sold under the trade name Cristamid or HDPE. The material at the distal end being selected for a higher flexibility, crease resistance, such as a polyamide with lower durometer or Pebax material (polyamid elastomer). In a transition area the material starts as a high 100 percent of the A property and transitions to 100 percent of the B property. This transition area in a preferred embodiment is less than one centimeter; however, the transition area can be up to lengths of 25 centimeters.
[0157] [0157]FIG. 20B is an enlarged view of the outer sheath 382 extending from the distal end to the proximal end, with portions broken away. The inner shaft 372 and stent 10 have been removed from FIG. 20B to allow greater visibility of the metal braided coil. The metal braid is formed of a flat wire having a width of between 0.001 inches (0.025 mm) and 0.005 inches (0.13 mm) and a thickness of 0.001 inches (0.025 mm). For the LCP fiber braid, the width is 0.003 inches (0.076 mm) and a thickness of 0.0007 inches (0.018 mm) diameter. The stiff materials could also be polyester (PET), LCP (liquid crystal polymer), PEEK, PBT, etc. and the soft material could be polyester elastomer, Arnitel or Hytrel. Weave patterns can be one-over-ore or two-over-two. The pick density could be 20 pick/in or 120 pick/in, or vary in between.
[0158] While the tailoring of the properties of the outer sheath 382 can be done for main purpose of ensuring sufficient strength and flexibility. For example, it is desirable that the distal end have sufficient flexibility and still have sufficient hoop or radial strength to prevent the self expanding stent from rupturing the sheath The tailoring of the properties can allow the overall wall thickness and therefore the outer diameter to be reduced.
[0159] The dimensions given are for a preferred embodiment. It is recognized that the dimension and properties will vary depending on the intended use of the delivery system. For example, the overall outer diameter of the composite outer sheath 382 could vary from under 3 French (e.g. for a Radius™ (Coronary) delivery system) to 20 French or larger (e.g. For a colonic or aortic delivery system). The wall thickness can vary from as thin as 0.003 inches for example, for coronary use, to as thick as 0.050 inches, for example, for colonic or aortic use. In the preferred embodiment described here, the normal thickness is 0.005 inches. It is recognized that in addition to a seamless transition where the property of the outer layer, the fourth layer 398 , varies through a transition portion, the sections can vary more abruptly such as with lap joints.
[0160] Referring to FIG. 20C, a sectional view of the distal end of the outer sheath is seen. The inner layer 390 has an inner diameter of for example between 0.078 inches to 0.081 inches (1.98 to 2.06 mm) for a 7 French delivery system. The outer diameter of the inner layer is between 0.082 to 0.083 inches (2.1 mm) The second layer 392 , which encases the first layer 390 , has an outer diameter of 0.084 inches (2.1 mm). The third layer with a fiber braid of 0.0007 inches has an outer diameter of 0.0868 inches (2.2 mm). The open area of the third layer is filled with material from both the fourth layer and the second layer. The fourth layer has an inner diameter of between 0.087 inches and 0.088 inches (2.21 mm to 2.23 mm) and an outer diameter of between 0.091 inches and 0.092 inches (2.31 mm and 2.34 mm).
[0161] The third layer which consists of LCP fiber braid or metal braided coil could have variable pick density from proximal end to distal end. At the proximal end, the pick density is 20 pick/in for additional stiffness and tensile strength, and at the distal end, the pick density is 120 pick/in for additional flexibility and radial strength to restrain the stent in the delivery system. The transition length can be abrupt or gradual (1 cm to 25 cm).
[0162] An alternative embodiment of an “over-the-wire” delivery system 400 is shown in FIG. 21. The delivery system 400 has an outer sheath 402 formed of a plurality of layers. The outer layer as its material properties vary as it goes from the proximal end to the distal end.
[0163] In a preferred embodiment, the properties are divided into two materials and a combination of these materials in the transition area. For example, the first portion is a material/blend chosen for higher stiffness, crush-strength and having relative high durometer. The material at the distal end being selected for a higher flexibility, crease resistance and with a lower durometer.
[0164] In a preferred embodiment, the outer sheath does not have a layer containing a polymer or metal braided coil.
[0165] Referring to FIG. 22A, an alternative embodiment of a stent 410 is shown flat layout. The stent 410 is formed OF elongated strands 412 such as elastic metal wires. The wires 412 are woven to form a pattern of geometric cells 414 . The sides 416 a, 416 b, 416 c, and 416 d of each of the cells 414 are defined by a series of strand lengths 418 a, 418 b, 418 c, and 418 d. Each of the sides 416 are joined to the adjoining side at an intersection where the strands 412 in this embodiment are either helically wrapped about each other to form interlocking joints 420 or joined to form a box node 422 . The interlocking joints 420 are discussed above with respect to FIGS. 2A and 2B.
[0166] Referring to FIG. 22E, the box node 422 is formed of a series of elements. The top of the box node 422 has an interlocking joint 420 where the strands 412 which extend from above cross each other. The strands 412 then extend down to form the sides of the box node 422 . The strands 412 then cross each other on the bottom of the box node 422 in another interlocking joint 420 . The respective strands therefore enter and exits the box node 422 from the same side. This is in contrast to the typical interlocking joint 420 or a cross joint, wherein the strands enter and exit at opposite corners of the joint. A cross joint is further explained above with respect to FIGS. 2A, 2B, and 3 . The strands 412 are shown representing their path in exploded perspective view. (The interlocking joint 420 does not allow the strands 412 to normally separate like this.)
[0167] The box node constrains the displacement of the cell and introduces local stiffness. By varying the number of nodes and location of nodes the degree of stiffness can be controlled. With this approach, as required, the stent can have different local mechanical properties (radial strength, column strength, etc.) without compromising flexibility. For example, the ends of the stent can be significantly stiffer than the middle portion or vice versa. The node structure restricts dilation and foreshortening of the stent during flexing, bending, and extension.
[0168] [0168]FIG. 23A is a flat layout view of another embodiment of the stent 410 ′. In this embodiment, the stent 410 ′ has a plurality of joints at the same level around the circumference of the tubular stents. The majority of the joints are interlocking Points 420 . In this embodiment, one of the joints of the plurality of the joints around the circumference is a box node joint 422 . The placement of the node joints 422 are located along a diagonal 426 of the stent 410 .
[0169] [0169]FIG. 23B is a flat layout view of an alternative embodiment of the stent 410 ′. In this embodiment, generally two joints of the plurality of the joints around the circumference is a box node joint 422 . The placement of the box node joints are each along a diagonal. The diagonals are at any angle to each other, therefore in certain locations the box node joint for each diagonal is one in the same.
[0170] [0170]FIG. 24A is a schematic of an oblique view of a stent. The strands have been removed from FIG. 24B for clarity. The position of the box nodes are shown. In a preferred embodiment, the nodes are on alternating oblique planes. The nodes are located on opposing oblique planes. Positioning of the oblique planes also constitutes a pattern. The nodes may be placed on both oblique planes, as illustrated in FIG. 24B, also with a repeating pattern.
[0171] During deformation (bending, twisting, etc.) the oblique planes accommodate (dissipates) the transfer of forces and displacements instead of simply transmitting the deformation to the next region of the stent. Selecting the planes at opposing angles causes the stent to have a neutral response. Alternatively, the angle can be chosen to yield a preferred bending direction or plane. Locating the nodes on an oblique plane will cause the nodes to collapse in a staggered mariner. When the tent is in a loaded conformation, the nodes will not co-locate in the same perpendicular plane. This increases the packing efficiency when in its loaded conformation.
[0172] A method of making the stent 410 is shown in FIGS. 25A and 25D. A mandrel 432 has a plurality of pins 434 on the outer surface of the mandrel in a pattern that determines the geometric cell 436 pattern. The strands 412 are bent around the top portion 438 of each top anchoring pin 434 to form the proximal end 440 of the stent 410 . The strands 412 are then pulled diagonally downward to an adjacent anchoring pin 434 where the strands 412 are joined. The strands 412 are helically wrapped about each other to form the interlocking joint 420 , with each strand passing through a single 360 degree rotation. The two strands are pulled taught so that the interlocking joint 420 rests firmly against the bottom portion 444 of the anchoring pin 434 such that each strand 412 is maintained in tension.
[0173] Where a box node 422 is desired, the mandrel 432 has a pair of anchoring pins 434 for each box node 422 . The strands 412 are helically wrapped about each other to form an interlocking joint 420 and positioned between the anchoring pins 434 . The strands 412 extend down the sides of the lower anchoring pin 434 . The strands 412 are then helically wrapped about each other to form the interlocking joint 420 , with each strand passing through a single 360 degree rotation. The two strands are pulled taught so that the interlocking joint 420 rests firmly against the bottom portion 444 of the anchoring pin 434 such that each strand 412 is maintained in tension.
[0174] In a preferred embodiment, the anchoring pins 434 are square with the edges having appropriate radii. The square pins retain the helically wrap of the strands in a proper position.
[0175] The free ends of the strands 412 are then pulled downward to the next diagonally adjacent anchoring pin 434 This process is continued until the desired length of the stent 410 is achieved The stent 410 is then heat-treated. The strands 412 at the joining end of the stent 410 are attached, for example, by ball welding or laser welding the ends of the wires as discussed above.
[0176] An alternative stent 450 is shown in a contracted position within the sleeve 452 in FIG. 26A. Similar to previous embodiment, the stent 450 is formed of elongated strands 22 such as elastic metal wires. The wires 22 are woven to form a pattern of geometric cells 24 . The sides 26 a, 26 b, 26 c, and 26 d of each of the cells 24 are defined by a series of strand lengths 28 a, 28 b, 28 c, and 28 d. Each of the sides 26 are joined to the adjoining side at an intersection where the strands 22 are helically wrapped about each other to form interlocking joints 460 . In contrast to the previous embodiments, the helically wrapped joints 460 extend longitudinal in contrast to radial. A medical prosthetic stent with longitudinal joints and method of manufacturing such a stent is described in U.S. Pat. No. 5,800,519 on Sep. 1, 1998 and which is incorporated herewith by reference.
[0177] The strand angle a is increased in the compressed or constrained state of the stent in this embodiment. The strand angle can be in the range of 10°-80° depending upon the particular embodiment. Smaller strand angles between 10° and 45° often require a shortened cell side length L to maintain radial expansion force. Cell side lengths L in the range of 0.5 to 4 mm, for example, can be used with stent having these smaller strand angles. For stents with larger strand angles in the range of 3-8 mm can be used, depending on the expanded diameter of the stent, the number of cells and the desired radial expansion force.
[0178] In addition to FIGS. 26A and 26B where the joints extend longitudinal, it is recognized that other embodiments such as the box node can extend longitudinal.
[0179] Several delivery systems have been discussed above. It is recognized that an alternative delivery system 480 , that of a coaxial delivery system 480 , can be used. Referring to FIG. 27A, a stent 10 is positioned over an inner shaft 482 , which is a braided tube in a preferred embodiment at a distal end of the delivery system. The inner shaft 482 extends from a handle 484 located at the proximal end. The delivery system has an outer shaft 486 which extends from the proximal handle 484 to a point, which is proximal to the distal end 488 . The inner shaft 482 extends through a lumen 490 of the outer shaft from the proximal handle 484 and projects out the distal end of the outer shaft. The inner shaft 482 is free-floating within the lumen of the outer shaft 486 .
[0180] An outer sheath 492 overlies the inner shaft 482 and the outer shaft 486 from the distal end 488 to the proximal handle 484 . This is in contrast to previous delivery systems discussed wherein the outer sheath 492 ends at a point distal to the handle. The outer sheath 492 is movable relative to the inner shaft 482 and the outer shaft 486 by pulling the outer sheath 492 at the proximal handle end. A guide wire 496 extends through the inner shaft from the proximal handle to the distal end.
[0181] Referring to FIG. 27B, a sectional view of the inner shaft 482 protecting from the lumen 490 of the outer shaft 486 is shown. The outer sheath 492 is coaxial with the inner shaft 482 and the outer shaft 486 . The properties of the inner shaft 482 , outer shaft 486 , and outer sheath 492 can be similar to those discussed above with respect to other embodiments.
[0182] While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
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The present invention relates to a system for delivering a medical prosthesis into a body lumen. A preferred embodiment of the invention utilizes a catheter having a stent mounted at the distal end that is released into the body lumen by movement of an outer sheath covering the stent in the proximal direction. The stent expands to conform to the inner wall of the lumen and the catheter is withdrawn.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation-in-part of U.S. application Ser. No. 10/714,230 filed Nov. 14, 2003, and also claims priority from U.S. Provisional App. Ser. No. 60/749,429, filed Dec. 12, 2005, the complete disclosures of which are incorporated herein by reference.
STATEMENT REGARDING GOVERNMENT SUPPORT
[0002] This invention was made in part with government support under Grant No. NAG3-2289 awarded by NASA, F-49620-01-1-0485 and F-49620-02-1-0062 awarded by the Air Force Office of Scientific Research and NCC3-1035 and NNC04GB67G awarded by NASA. The government has certain rights in this invention.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates generally to the field of photovoltaic or photoelectric materials and devices. More particularly, this invention relates to fabricating high efficiency, lightweight, cost effective, and flexible shaped thin film photo detectors and solar cells employing the donor-bridge-acceptor-bridge, or similar type, block copolymers.
[0005] 2. Background
[0006] Photovoltaic (PV) or photoelectric (PE) is a process where an open circuit voltage or a short-circuit electric current is generated in a media (materials or devices) as a result of light radiation. PV or PE devices therefore are able to convert solar energy directly into electric energy, or convert light signals into electrical signals. They are, therefore, very useful for renewable and clean energy generation, as well as optical signal processing.
[0007] Before discussing organic photovoltaics, we shall briefly compare a classic inorganic solar cell (such as the “Fritts Cell” reported in 1885 and described by J. Perlin, From Space to Earth—The Story of Solar Electricity, AATEC Publications, Ann Arbor, Mich., 1999) versus an organic solar cell (such as the “Tang Cell” described by C. Tang in U.S. Pat. No. 4,164,431 in 1979 and in “Two-layer organic photovoltaic cell,” Appl. Phys. Lett., 48, 183 (1986)).
[0008] As shown in FIG. 1 , the “Fritts Cell” was composed of a semiconducting selenium thin layer sandwiched between two different thin layer metal electrodes, one gold layer acting as a large work function electrode (LWFE) and the other metal layer acting as a small work function electrode (SWFE). In this cell, when an energy matched photon strikes the selenium, a free electron is generated in the connection band (CB), and a free hole was left in the valence band (VB) as shown in FIG. 2 . The free electron and hole (also called “charged carriers” or simply “carriers”) can easily be separated from each other, even by thermal energy at room temperature, and they can diffuse to the respective and opposite electrodes under a field created by the two different work function metal electrodes.
[0009] In contrast, in the first organic solar cell (the “Tang Cell”), as shown in FIG. 3 , when an energy matched photon strikes an organic unit, it only generates a neutral and tightly bonded electron-hole pair called an “exciton.” It is believed that the neutral exciton can diffuse randomly in any direction, even under a static electric field. However, if two different organic materials (or “phases”) are present and in direct contact with each other, one material has a higher set of the Lowest Unoccupied Molecular Orbital/Highest Occupied Molecular Orbital (“LUMO/HOMO”) levels, called a “donor,” and the other material has a lower set of LUMO/HOMO levels, called an “acceptor,” as shown in FIG. 4 , then, when a photo-generated exciton diffuses and reaches an interface of the donor and acceptor, if the exciton is at the donor side, the photo-generated electron at the donor LUMO will transfer into the acceptor LUMO. If the exciton is at the acceptor side, the photo-generated hole at the acceptor HOMO will jump into the donor HOMO (corresponding to an electron back transfer). Thus, a neutral exciton now becomes a free electron (at the acceptor LUMO) and a free hole (at the donor HOMO). Now the freed electrons and holes can diffuse to the respective electrodes in two separate phases. Thus, a donor/acceptor binary system appears to be critical for organic photovoltaics. For organic solar cells, the power conversion efficiencies are limited by at least the following steps:
1) Photon absorption or exciton generation; 2) Exciton diffusion to donor/acceptor interfaces; 3) Exciton separation or charged carrier generation; 4) Carrier transportation (diffusion) to respective electrodes; and 5) Carrier collection by the electrodes.
[0015] For all currently reported organic or polymeric photovoltaic devices, none of the above-mentioned five steps have been optimized. It is, therefore, not surprising that the power conversion efficiency of those reported organic or polymeric solar cells is very low in comparison to typical inorganic solar cells.
[0000] Photon Absorption or Exciton Generation
[0016] In this first step of organic photovoltaics, a critical requirement is that the material's optical excitation energy gap (“optical gap”) must be equal to or smaller than the incident photon energy. In organic systems, this gap is the energy gap between the Highest Occupied Molecular Orbital (“HOMO”) and the Lowest Unoccupied Molecular Orbital (“LUMO”). For molecules containing double or triple bonds (π orbitals), HOMO typically refers to the highest occupied π orbital(s) (such as π bonding orbitals at ground state), and LUMO refers to the unoccupied π orbitals (such as π* anti-bonding orbitals at ground state). For molecules containing only single bonds (σorbitals), HOMO typically refers to the highest occupied σ orbital(s) (such as σ bonding orbitals at ground state) and LUMO refers to the unoccupied σ orbitals (such as σ* anti-bonding orbitals at ground state). Since an organic HOMO to LUMO excitation only generates an exciton instead of a free electron and hole, “optical gap” is commonly used here instead of the traditional electronic “band gap” that typically refers to the energy gap between the free holes at valence band (VB) and the free electrons at conduction band (CB) in a semiconducting inorganic material ( FIG. 2 ). In organic materials, the relationship of “optical gap (E go )” versus “electronic gap (E ge )” can be expressed as E go =E ge +E eb , where E eb is called exciton binding energy. E go values can be conveniently obtained from materials UV-VIS absorption spectra. E ge values may be estimated by electrochemical analysis such as cyclic voltammetry (CV), as described by S. Janietz, et al., “Electrochemical determination of the ionization potential and electron affinity of poly(9,9)-dioctylfluorene,” Appl. Phy. Lett., 73, 2453-2455 (1998), incorporated herein by reference. For a widely used conjugated and semiconducting polymer poly-p-phenylenevinylenes, or PPV, the exciton binding energy is about 0.4-0.5 eV, as quoted by T. Stubinger, et al., “Exciton diffusion and optical interference in organic donor-acceptor photovoltaic cells,” J. Appl. Phys., 90(7), 3632 (2001), incorporated herein by reference. For solar cell applications, since solar light radiation spans a wide range yet with largest photo-flux (at 1.5 air mass) in the range of 600-900 nm (1.3-2.0 eV), as quoted by C. Brabec, et al., in Organic Photovoltaics: Concepts and Realization, Springer, Berlin, 2003, incorporated herein by reference; therefore, the ideal optical band gap of an organic solar cell should match this radiation range. Unfortunately, several widely used conjugated semiconducting polymers all have optical gaps higher than 2.0 eV, as cited in T. A. Skotheim, et al., Handbook of Conducting Polymers, 2d ed., Marcel Dekker, N.Y., 1998. For instance, poly-p-phenylenevinylene (PPV) has a typical optical gap of about 2.5 eV, well above the maximum solar photon flux range. This is why the photon absorption (exciton generation) for PPV-based solar cells is far from optimal. This “photon loss” problem is in fact very common in almost all of the reported organic photovoltaic materials and devices. However, one advantage of organic materials is their versatility to fine-tine the energy levels via molecular design and synthesis; therefore, there is still ample room for improvement. A number of recent studies on the developments of low band gap conjugated polymers are such examples. For instance, N. Sariciftci, et al., described “A Low-Bandgap Semiconducting Polymer for Photovoltaic Devices and Infrared Emitting Diodes,” Adv. Funct. Mater., 12, 709-712 (2002), incorporated herein by reference.
[0000] Exciton Diffusion
[0017] Once an exciton (tightly bonded electron-hole pair) is photo-generated, it typically will decay (radiatively or non-radiatively) back to ground state at nanoseconds or longer time frames. Alternatively, in the solid state, some excitons may be trapped in solid defect, or “doping,” sites. Both of these situations would contribute to the “exciton loss.” However, even within its short lifetime, an exciton on a conjugated polymer chain can diffuse to a remote site via inter-chain and intra-chain interactions, or coupling. The interaction can be either via hopping or via energy transfer (for a single exciton, for instance, it can be a Forster energy transfer process), as described by J. Schwartz, et al., in “Control of Energy Transfer in Oriented Conjugated Polymer-Mesoporous Silica Composites,” Science, 288, 652 (2000), incorporated herein by reference. For conjugated organic materials, the average exciton diffusion length (limited by the exciton lifetime and the material's morphology) is typically in the range of 10-100 nm, as cited by T. Stubinger, et al. For instance, the average diffusion length for PPV is around 10 nm. This means that the best way to minimize the “exciton loss” would be to build a material with a defect-free tertiary nanostructure, such that an exciton generated at any site of the material can reach a donor/acceptor interface in all directions within the average exciton diffusion length. One limitation of the “Tang Cell” is that, if the donor or acceptor layer is thicker than the average exciton diffusion length (10-100 nm), then “exciton loss” would be a problem. However, if the photovoltaic active layer thickness is well below the excitation photon wavelength (600-900 nm in the case of a solar cell), then “photon loss” would become a problem. Most importantly, the double layer structure has a relatively small donor/acceptor interface in comparison to blends.
[0000] Exciton Separation/Carrier Generation
[0018] Once an exciton diffuses to a donor/acceptor interface, or an exciton is generated near the interface, the interface potential field generated by the donor/acceptor HOMO/LUMO differences would then separate the exciton into a free electron at acceptor LUMO and a free hole at donor HOMO, provided such field is sufficient enough to overcome the exciton binding energy (E eb ). This electron transfer process is also called “photodoping,” as it is a photo-induced reduction-oxidation or “Redox” process between the donor and the acceptor. On the other hand, the LUMO/HOMO pair difference between the donor and acceptor should not be too large, as that will not only reduce the open circuit voltage (V oc ) that is closely related to the donor HOMO and acceptor LUMO, as reported by C. J. Brabec, et al., in “Origin of the open circuit voltage of plastic solar cells,” Adv. Funct. Mater., 11, 374-380 (2001), incorporated herein by reference. It may also incur ground state electron transfer from the donor HOMO directly to the acceptor LUMO (“chemical doping”). Therefore, an ideal LUMO/HOMO pair difference between the donor and the acceptor appears to be around the exciton binding energy (E eb ). For a PPV donor and fullerene acceptor binary system, it has been found that the photo-induced electron transfer process at the PPV/fullerene interface occurs at sub-picoseconds, as reported by A. J. Heeger, et al., in “Subpicosecond photoinduced electron transfer from conjugated polymers to functionalized fullerenes,” J. Chem. Phys., 104, 4267-4273 (1996), incorporated herein by reference, about three orders of magnitude faster than the average PPV exciton decay. This means opto-electronic quantum efficiency at such interface is almost unity, and a high efficiency organic photovoltaic system is quite possible.
[0000] Carrier Diffusion to the Electrodes
[0019] Once the carriers (free electrons or holes) are generated, holes need to diffuse toward the large work function electrode (LWFE), and electrons need to diffuse toward the small work function electrode (SWFE). The driving force here for the carriers is the relatively weak field generated by the two different work function electrodes. In addition, another driving force called “chemical potential” may also play a role, as described by B. Gregg in “Excitonic Solar Cells,” J. Phys. Chem. B., 107, 4688-4698 (2003), incorporated herein by reference. “Chemical potential” driving force can be interpreted simply as a density-driven force, i.e., particles tend to diffuse from a higher density domain to a lower density domain. In an organic donor/acceptor binary photovoltaic cell, for instance, high density electrons at the acceptor LUMO near the donor/acceptor interface tend to diffuse to a lower electron density region within the acceptor phase, and high density holes at the donor HOMO near the donor/acceptor interface tend to diffuse to the lower hole density region within the donor phase. For instance, in the “Tang Cell,” as shown in FIG. 3 , at the donor/acceptor (D/A) interface, once an exciton is separated into a free electron in the acceptor side and a free hole in the donor side, the electron will be “pushed” away from the interface toward the negative electrode by both the “chemical potential” and by the field formed from the two electrodes. The holes will be “pushed” toward the positive electrode by the same forces but in the opposite directions. With this chemical potential force, even if the two electrodes are the same, asymmetric photovoltage or photocurrent could still be achieved (i.e., the donor side would be positive and the acceptor side negative). However, right after electron-hole separation at the interface, they can also recombine, though at a much slower rate of micro- to milliseconds. Additionally, the diffusion of electrons and holes to their respective electrodes is not really smooth due to poor morphology of most currently reported organic photovoltaic systems. If all LUMO and HOMO orbitals are well-aligned and overlapped with each other in both donor and acceptor phases, like in molecularly self-assembled thin films, then the carriers will be able to diffuse much more smoothly in a “band” type of pathway toward their respective electrodes. As a matter of fact, it has been demonstrated that molecular self-assembly in polythiophene enhances carrier mobility significantly, as described by Z. Bao, et al., in “Soluble and processable regioregular poly(3-hexylthiophene) for thin file-effect transitor applications with high mobility,” Appl. Phys. Lett., 69, 4108 (1996), incorporated herein by reference. Currently, carrier “hopping” and “tunneling” are believed to be the dominant conductivity mechanism for most reported organic photovoltaic systems, and the “carrier loss” is believed to be a key factor for the low efficiency of organic photovoltaic materials and devices.
[0000] Carrier Collection at the Electrodes
[0020] It has been proposed by G. Yu, et al., in “Polymer Photovoltaic Cells: Enhanced Efficiencies via a Network of Internal Donor-Acceptor Heterojunctions,” Science, 270, 1789 (1995), incorporated herein by reference, that when the acceptor LUMO level matches the Fermi level of the small work function electrode, and the donor HOMO matches the Fermi level of the large work function electrode, a desired “Ohmic” contact might be established for efficient carrier collection at the electrodes. So far, there are no organic photovoltaic systems that have realized this desired “Ohmic” contact due to the availability and limitations of materials and electrodes involved. There were a number of studies, however, focusing on the open circuit voltage (V oc ) dependence on materials LUMO/HOMO levels, electrode Fermi levels, and chemical potential gradients, as stated above. The carrier collection mechanisms at electrodes are relatively less studied and less understood. It is believed that the carrier collection loss at the electrodes is also a major contributing factor to the low efficiency of current organic solar cells.
[0021] Though there are a number of attempts to design or fabricate “bicontinuous” nanostructures for photovoltaic applications, such as those proposed by Salafsky in U.S. Pat. No. 6,239,355 B1, by A. Alivisatos, et al., in “Hybrid Nanorod-Polymer Solar Cells,” Science, 295, 2425 (2002), incorporated herein by reference, and by A. Cravino, et al., in “Electrochemical and Photophysical Properties of a Novel Polythophene with Pendant Fulleropyrrolidine Moieties: Toward ‘Double Cable’ Polymers for Optoelectronic Devices,” J. Phys. Chem., B, 106, 70 (2002), incorporated herein by reference. Unfortunately, nanoparticles, nanorods, or fullerenes cannot form a continuous pathway for charged carriers (such as electrons) to transport smoothly.
[0022] The block copolymer approach to photovoltaic functions offers some intrinsic advantages that could hardly be achieved in composite bilayer or blend devices. Block copolymer melts are known to exhibit behavior similar to conventional amphiphilic systems such as lipid-water mixtures, soap, and surfactant solutions, as summarized by M. Lazzari, et al., in “Block Copolymers for Nanomaterial Fabrication,” Adv. Mater. 15, 1584-1594 (2003), incorporated herein by reference. The connection between distinct blocks imposes severe constraints on possible equilibrium states, which results in unique supra-molecular nanodomain structures such as lamellae (LAM), hexagonally (HEX) packed cylinders or columns, spheres packed on a body-centered cubic lattice (BCC), hexagonally perforated layers (HPL), and at least two bicontinuous phases: the ordered bicontinuous double diamond phase (OBDD) and the gyroid phase. The morphology of block copolymers is affected by composition, block size, temperature and other factors. Though a MEH-PPV/polystyrene (with partial C 60 derivatization on polystyrene block) donor/acceptor diblock copolymer system has recently been reported by G. Hadziionnou, et al., in “Supramolecular self-assembly and opto-electronic properties of semiconducting block copolymers,” Polymer, 42, 9097 (2001), incorporated herein by reference, and phase separation between the two blocks was indeed observed. The polystyrene/C 60 acceptor block is, however, not a conjugated chain system; the poor electron mobility, or “carrier loss” problem in the polystyrene phase, is still not solved. On the other hand, when a conjugated donor block was connected directly with a conjugated acceptor block to form a p-n type conjugated diblock copolymer, as reported by S. A. Jenekhe, et al., in “Block Conjugated Copolymers: Toward Quantum-Well Nanostructures for Exploring Spatial Confinement Effects on Electronic, Optoelectronic, and Optical Phenomena,” Macromolecules, 29, 6189 (1996), incorporated herein by reference, though energy transfers from higher optical gap block to lower optical gap block were observed, no charge separated states were identified; therefore, it is not usable for photovoltaic functions.
[0023] Accordingly, it is an object of the present invention to provide an improved system for converting solar energy into electric energy.
[0024] Another object of the present invention is to provide an improved system for renewable and clean energy generation.
[0025] Another object of the present invention is to provide an improved, high efficiency system capable of capturing a greater range of energy.
[0026] Another object of the present invention is to provide a system for converting solar energy into electric energy which reduces or eliminates losses found in previous systems.
[0027] Yet another object of the present invention is to provide an improved, high efficiency system which is light weight, flexible in shape-and cost effective.
[0028] Finally, it is an object of the present invention to accomplish the foregoing objectives in a simple and cost-effective manner.
SUMMARY OF THE INVENTION
[0029] An improved organic photovoltaic device is provided which consists of a conjugated donor block and a conjugated acceptor block joined together by a non-conjugated bridge. The conjugated donor block has a higher highest occupied molecular orbital and a higher lowest unoccupied molecular orbital than the conjugated acceptor block. The non-conjugated bridge has a highest occupied molecular orbital which is lower than the highest occupied molecular orbital of the conjugated donor block and the conjugated acceptor block and a lowest unoccupied molecular orbital which is higher than the lowest unoccupied molecular orbital of the conjugated donor block and the conjugated acceptor block. The non-conjugated bridge is preferably flexible and formed such that it is able to bend 180°. A plurality of conjugated donor blocks and conjugated acceptor blocks may be alternately joined by non-conjugated bridges and stacked or formed in to columns. In the column format, the columns are sandwiched by a positive electrode and a negative electrode. In a further preferred embodiment, a thin donor layer is formed between the positive electrode and the columns and a thin acceptor layer is formed between the negative electrode and the columns.
[0030] The device is preferably formed a follows. Photovoltaic block copolymer samples are synthesized and then dissolved in a solvent which will preferably dry conveniently. Preferably, the copolymer samples are synthesized by individually synthesizing conjugated donor chains, conjugated acceptor chains and non-conjugated bridge chains, combining the non-conjugated bridge chains with either the conjugated donor chains or the conjugated acceptor chains to form a plurality of bridge-donor-bridge units or bridge-acceptor-bridge units, and combining the formed units with the remaining complimentary conjugated chains. The mixture is then filtered. A film of the filtered mixture is formed on a prepared surface, preferably conducting glass, by spin coating or drop drying or other appropriate method and the solvent is removed by heating, vacuum or a combination. To achieve the desired chain direction, the structure may then be heated and exposed to a magnetic, electrical or optical force.
[0031] An aspect of the present invention is a tandem style device including a plural or multiple stacked sub-cell pack, preferably with excitation energy gap grading. The tandem device may include a conductive transparent layer interposed between the sub-cells, and preferably includes a transparent electrode at the side receiving incident light and a transparent or opaque electrode at the other side.
DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 shows a simple prior art inorganic semiconductor solar cell, or “Fritts Cell.”
[0033] FIG. 2 illustrates energy levels and photo-electric processes in the “Fritts Cell.”
[0034] FIG. 3 shows a simple prior art organic solar cell, or “Tang Cell.”
[0035] FIG. 4 illustrates energy levels and intermolecular photo-electric processes in the “Tang Cell.”
[0036] FIG. 5 shows the “primary structure” of the invented block copolymer.
[0037] FIG. 6 illustrates energy levels of the invented -DBAB- type block copolymer system.
[0038] FIG. 7 shows an example of the “secondary structure” of the invented block copolymer thin film.
[0039] FIG. 8 shows an example of the “tertiary structure” of the invented block copolymer thin film.
[0040] FIG. 9 shows a first example photovoltaic cell using the invented block copolymer.
[0041] FIG. 10 shows a second example photovoltaic cell using the invented block copolymer.
[0042] FIG. 11 shows structures and key synthetic schemes of a specific -DBA- block copolymer already tested.
[0043] FIG. 12 shows a diagram of a -DBAB- type photovoltaic cell already fabricated and tested.
[0044] FIG. 13 shows the photo current test results for one fabricated -DBAB- block copolymer photovoltaic cell.
[0045] FIG. 14 shows the structure of a tandem device using sub-cells of block copolymer photovoltaic.
[0046] FIG. 15 shows the sub-cell structure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0047] The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of an embodiment of the invention.
[0048] In order to address the loss issues discussed above, a photovoltaic device based on a -DBAB-type of block copolymer system, as shown in FIG. 5 , has been provided. Aspects of the invention are described in “Design of a Block Copolymer Solar Cell,” Sol. Energy Mater. Sol. Cells, 79, 257-264 (2003), incorporated herein by reference. In this novel block copolymer system, D is a π electron conjugated donor block with an optical gap matching the desired photon flux and energy (i.e., solar spectra and maximum photon flux range in case of solar cells, or optical signal wavelength in case of photo detectors), A is a conjugated acceptor block, also with an optical gap matching the desired photon energy and maximum flux, and the energy level differences between the donor and acceptor blocks are such that it is just sufficient enough to overcome the exciton binding energy. B is a non-conjugated and flexible bridge unit with a much higher band gap than both the donor and the acceptor blocks, as shown in FIG. 6 . Since both the donor and acceptor blocks are ?r electron conjugated chains, good carrier transport in both donor and acceptor phases now becomes feasible.
[0049] A non-conjugated and flexible bridge unit (such as an aliphatic chain containing only a bonds) is important because: (1) a non-conjugated bridge unit will hinder the intra-chain electron-hole recombination due to the partially insulating nature of organic single bond chains; (2) intra- or inter-molecular energy and electron transfer or electron-hole separation can still proceed effectively through a bonds or through space under photo-excitations, as shown by M. R. Wasielewski, et al, in “Factoring through-space and through-bond contributions to rates of photoinduced electron transfer in donor-spacer-acceptor molecules,” J. Photochem. & Photobiol. (A), 102(1), 71 (1997), incorporated herein by reference; (3) the flexibility of the flexible bridge unit would also enable the rigid donor and acceptor conjugated blocks more easily to phase separate and self-assemble and be less susceptible to conjugation distortion. This -DBAB- backbone can be called the “primary structure” ( FIG. 5 ). Additionally, the substituents of donor and acceptor blocks can be fine-tuned in such a way that one could introduce forces similar to those exhibited in the derivatized regioselective polythiophenes, as shown by Z. Bao, et al., to induce the π orbital closely stacked and ordered “secondary structure” as one example shown in FIG. 7 . The π orbital stacked “secondary structure” has been found to exhibit dramatically enhanced carrier mobility due to improved π orbital overlapping. Finally, through the adjustment of block size, block derivatization, and multi-layer processing protocols, a “tertiary structure,” as shown in FIG. 8 , where a “HEX” or columnar- type block copolymer morphology is vertically sandwiched between a larger work function positive electrode (e.g., ITO-coated transparent sheet or glass) and a smaller work force function negative electrode e.g., aluminum or calcium) can be realized, as shown in FIG. 9 . Even better, a thin donor layer can be sandwiched between the LWFE and block copolymer layer and a thin acceptor layer can be sandwiched between the SWFE and block copolymer layer, as shown in FIG. 10 . This second device structure would enable a desired asymmetry and favorable chemical potential gradient for asymmetric (selective) carrier diffusion and collection under even the two same electrodes. Since the diameter of each donor or acceptor block column can be conveniently controlled via synthesis and processing to be within the typical organic exciton diffusion range of 10-100 nm, every photo-induced exciton will be in convenient reach of a donor/acceptor interface. At the same time, photo-generated carriers can diffuse more smoothly to their respective electrodes via a truly “bicontinuous” or “channeled” block copolymer “HEX” or related columnar morphology. While the increased donor and acceptor interface size and phase morphology will dramatically minimize the exciton and carrier losses, it nevertheless may also increase the carrier recombination at the same interfaces. However, this charge recombination typically occurs on the microseconds or slower timescale, and this is in contrast to the ultra-fast femto-second charge separation rate at the same interface. Therefore, the charge carrier recombination does not appear to be of a major concern for solar cell applications where the radiation is continuous. The charge recombination may also be minimized by fine-tuning the energy levels of the materials, as the energy level differences also affect charge recombination rate. This block copolymer photovoltaic device may, to a certain degree, minimize a dye-sensitized solar cell (DSSC), as reported by M. Graetzel, et al., in “Molecular Photovoltaics,” Acct. Chem. Res., 33, 269 (2000), incorporated herein by reference, yet with whole donor/acceptor interface covered by photo-sensitizing dyes (band gap matched donor or acceptor units), and that both donor and acceptor phases are solids with good orbital overlap. Additionally, with appropriate adjustment of donor and acceptor block sizes and their substituents, energy levels, or with attachment of better photon energy matched sensitizing dyes on the polymer backbone, it is expected that the photon loss, the exciton loss, and the carrier loss (including charge recombination) issues can all be addressed and optimized simultaneously in one such -DBAB- type block copolymer photovoltaic device.
[0050] In order to examine or test the feasibility of this block copolymer solar cell design, a specific -DBAB- type of block copolymer was recently synthesized and characterized, and some opto-electronic studies are already in progress, as reported by S. Sun, et al., see, e.g., “Synthesis and Characterization of a Novel -BDBA- Block Copolymer System for Light Harvesting Applications,” in Organic Photovoltaics III, SPIE, 4801, 114-124 (2003), incorporated herein by reference, and “Conjugated Block Copolymers for Opto-Electronic Functions,” Syn. Met. 137, 883-884 (2003), incorporated herein by reference.
[0051] As briefly summarized earlier, a -DBAB- or similar analogs, such as -DBA-, -DBABD-, -ABDBA-, etc., as shown schematically in FIG. 5 , is essential in this invention. Both donor and acceptor are conjugated chain (or block), with the donor having higher LUMO/HOMO levels than the acceptor block, and with the energy level difference preferably closer to the exciton binding energy corresponding to the type of conjugated units, e.g., 0.4-0.5 eV for PPV type conjugated polymers. Additionally, the LUMO/HOMO optical gap of both donor and acceptor preferably match the photon energy, e.g., 1.3-2.0 eV in case of solar cell applications. Typically, the HOMO/LUMO levels in organic materials can be adjusted via electro-active group substitutions on the conjugated chain. The LUMO/HOMO values may be estimated using certain known theoretical models and calculation methods as described by J. L. Bredas, et al., in “Chain-Length Dependence of Electronic and Electrochemical Properties of Conjugated Systems: Polyacetylene, Polyphenylene, Polythiophene, and Polypyrrole,” J. Am. Chem., 105, 6555-6559 (1983), incorporated herein by reference, or may be experimentally measured after the materials are synthesized as elaborated below. The size (or main chain length) of the donor or acceptor conjugated chain should be no shorter than the typical size of an intra-chain exciton corresponding to the type of conjugated units, and no longer than the average exciton diffusion length corresponding to the type of conjugated units. In PPV for example, the conjugated chain size is preferably between 2-10 nm (corresponding to 3-15 phenylene-vinylene repeating units). The bridge chain should be such that, after coupling with a donor on one end and an acceptor on the other end, at least three consecutive single (σ) bonds exist on the bridge chain, and the LUMO level of the bridge is higher than the LUMO of both the donor and acceptor chains, and that the HOMO level of the bridge is lower than the HOMO of both the donor and acceptor chains, as shown in FIG. 6 . In general, most aliphatic chains containing only single (σ) bonds can satisfy this LUMO/HOMO energy level requirement. A minimum of three consecutive single bonds would not only ensure a non-conjugated large band gap energy barrier between the two conjugated chains, it also enables the bridge a 180° bending capacity from the “primary structure” shape, as shown in FIG. 5 to the vertically stacked “secondary structure,” as shown in FIG. 7 .
[0052] While a number of ways or strategies may be used to synthesize the target -DBAB- type of block copolymers, at least one strategy or method follows: A two-end functionalized donor chain, a two-end functionalized acceptor chain, and a two-end functionalized bridge chain are synthesized first and separately, and the end functional group of each chain should be such that both donor and acceptor chains will react and couple with the bridge chain, yet the donor chain will not react with the acceptor chain and vice-versa, and each chain will not react with itself. Once individual chains are prepared, then either the donor or the acceptor chain is added by drops to an excess amount of the bridge chain, such that predominantly -BDB- or -BAB- units are formed first. Then -BDB- can react with acceptor (A) chain in a 1:1 molar ratio, or the -BAB- chain can react with the donor (D) chain in a 1 : 1 molar ratio. Thus, the final conjugated units of -DBAB- can be synthesized. Such a synthetic protocol has already been demonstrated experimentally by S. Sun, et al., in “Synthesis and Characterization of a Novel -BDBA- Block Copolymer System for Light Harvesting Applications,” in Organic Photovoltaics III, SPIE Proc., 4801, 114-124 (2003), incorporated herein by reference, and as shown in FIG. 10 .
[0053] Once the donor (D) and acceptor (A) chains are synthesized, their LUMO/HOMO levels should be measured or determined first before proceeding further. The experimental determination of LUMO/HOMO levels of organic materials may use standard literature procedures, for instance, those described by S. Janietz, et al., in “Electrochemical determination of the ionization potential and electron affinity of poly9,9-dioctylfluorene,” Appl. Phy. Lett., 73, 2453-2455 (1998), incorporated herein by reference. Once the measured LUMO/HOMO values indeed satisfy or meet the criteria set forth in this invention, then final -DBAB- type block copolymer synthesis can proceed according to the protocol described above.
[0054] Photovoltaic devices (cells or sub-cells) can be fabricated as follows: For a first device shown in FIG. 9 , the photovoltaic block copolymer samples first may be dissolved in an appropriate solvent that can be conveniently dried. Then the polymer solution needs to be filtered (preferably using a 0.2 micron pore size PTFE filter, i.e., Teflon®) to remove large insoluble particles. The sample solution can then be either spin coated or simply drop dried onto a pre-cleaned India Tin Oxide (ITO) conducting glass slide. The thickness of the thin film can be controlled in a number of ways, such as concentration of the solution, the spin coating speed (in case of spin coating), etc. The solvent residue can be removed by heating, exposure to a vacuum, or a combination of both, such as in a heated vacuum oven. The film thickness can be measured using a number of methods or tools; one such method is to use a commercially available profilometer. The thickness of the film needs to be controlled; if the film is too thick, photo-generated carrier loss would become larger, particularly for amorphous thin films without any molecular self-assembly. However, if the film is too thin, photon loss would be more severe as absorption is best when the film thickness is close to the wavelength of the photon. For solar energy applications, since the maximum solar photon flux is between 600-900 nm, an ideal thickness should be in this range. Yet in reality, due to the carrier loss problem, a balanced approach has to be applied; therefore, a 100-200 nm thick photovoltaic polymer layer is desirable and is typically applied in most organic PV cells fabricated so far.
[0055] Block copolymer supramolecular structure or morphology, defined as “secondary” and “tertiary” structures in this invention, is very critical for exciton diffusion, charge separation, and, particularly, carrier transportation. For instance, Schwartz, et al., in “Control of Energy Transfer in Oriented Conjugated Polymer-Mesoporous Silica Composites,” Science, 288, 652 (2000), incorporated herein by reference, demonstrated that the energy transfer (exciton diffusion) in a PPV system is more effective between the parallel aligned conjugated chains (inter-chain) than within the chain (intra-chain); however, charge carrier transportation is more effective or faster along the conjugated chain (intra-chain) than between the conjugated chains (inter-chain). This is one of the reasons that the example “secondary” and “tertiary” structures in this invention, as shown in FIG. 7-8 , are desirable and particularly beneficial for photovoltaic functions, since the excitons generated anywhere can now diffuse, or couple, among the vertically aligned conjugated chains efficiently, and the charged carriers will be able to transport efficiently along the vertically aligned conjugated chain to the respective top and bottom electrodes.
[0056] Block copolymer supramolecular structures and morphologies can be manipulated or controlled using a variety of methods. For instance, by using different film forming methods, such as spin coating, drop drying, ink-jet printing, roll-to-roll printing, by changing solvent or concentration, by simple heating after films are dried (also called thermal annealing), and by applying certain external forces such as magnetic, electric, or optical forces. For instance, for the example “secondary structure,” as shown in FIG. 7 , since the charges (positive and negative) can move more effectively along the conjugated chain direction, the external magnetic fields, electric fields, or polarized light could be a driving force for the preferential alignment of the rigid conjugated chains to the electric field direction. Recent reports of solar cell performance improvement after certain thermal and electrical post-treatments of a conjugated polymer/fullerene binary thin film may be evidence of such morphology improvements, as reported by F. Padinger, et al., in “Effects of Postproduction Treatment on Plastic Solar Cells,” Adv. Funct. Mater., 13, 1-4 (2003), incorporated herein by reference. Finally, a smaller work function metal electrode, such as aluminum, can be deposited on top of the block copolymer thin film using a standard vacuum thermal evaporation method.
[0057] FIG. 12 shows an example of a half-ITO covered photovoltaic device fabricated using the above-mentioned protocol. In this example device fabrication, for instance, a 20×40 mm sized ITO glass slide was immersed halfway into a concentrated sulfuric acid/chromerge cleaning solution for over 8 hours in order to dissolve part of the ITO covered area completely. The purpose of using a partially covered ITO glass is to avoid a possible electrode touching induced short circuit by creating an aluminum electrode contact area where there is no ITO conducting layer right below. Then the whole ITO glass was submerged briefly into a cleaning solution and was then rinsed with water and ethanol and dried. The ITO slide was then spin coated with approximately 100 nm thick polymer film from a polymer solution. After the film is dried, an aluminum electrode approximately 100 nm thick was vacuum deposited on top of the polymer film. The active area of the photovoltaic cell is defined by the area where aluminum is overlapping with an ITO layer. The active area size may be used to calculate the current density as defined by the total measured current divided by the active area. In this example fabrication, the active area is 10×10 mm.
[0058] Once the photovoltaic cell is fabricated, the photo current can be measured by irradiating the cell from the transparent ITO glass slide and, at the same time, measuring the current from the ITO (positive) electrode to the aluminum (negative) electrode using a sensitive current meter. FIG. 13 shows the photocurrent density comparison between several photovoltaic cells fabricated from 100 nm thick film of (1) an RO-PPV (donor) and an SF-PPV-I (acceptor) based -DBAB- block copolymer; and (2) RO-PPV/SF-PPV-I equal molar blend; and (3) commercially available MEH-PPV/fullerenes equal molar blend; and (4) current densities without light radiation (dark current). The light source in this case was a 150 W Xe lamp with a 15×15 mm beam size and a wavelength tunable by a monochromator inside an ISA Fluoromax-3 fluorescence spectrophotometer. The intensity of the light is about 0.01 Sun (i.e., one Sun equals 1000W/m 2 or 100 mW/cm 2 ).
[0059] As FIG. 13 demonstrates, the peak photocurrent of the -DBAB- film was almost doubled in comparison to the simple D/A blend. While the shape of the photocurrent versus wavelength reflects both materials' optical (photon) absorptions as well as light intensity variations, the significant photo current magnitude improvement at the same wavelength is a reflection of either (a) the increased donor/acceptor interface; or (b) better film morphology or smoother carrier transportation pathways; or (c) both factors. Thus, even these very preliminary and not yet optimized tests reveal the superiority of this invention.
[0060] Additionally, in order to further enhance charged carrier collections at the electrodes, a thin layer (about 1 nm thick) of lithium fluoride (LiF) can be vacuum deposited between the photoactive materials layer and the (metal) negative electrode, and a thin (50-100 nm) poly(ethylene dioxythiophene)/polystyrene sulfonic acid (PSS/PEDOT) layer can be spin coated (from an aqueous solution) between the ITO glass and the photoactive materials layer. Both LiF and PSS/PEDOT are commercially available and have been known to improve the carrier collection at the respective electrodes, as shown by C. Brabec, et al., in “Organic Photovoltaics: Concepts and Realization,” Springer, Berlin (2003), incorporated herein by reference.
[0061] A second photovoltaic device may also be fabricated, as shown in FIG. 10 . A thin donor layer (with thickness less than the average exciton diffusion range, such as 10 nm in case of PPV) is added between the positive electrode and the photovoltaic block copolymer layer, and another thin acceptor layer (also with a thickness less than the average exciton diffusion length) is also added between the photovoltaic block copolymer layer and the negative electrode. Additionally, a 50-100 nm thick PSS/PEDOT layer can be added between the positive electrode (such as an ITO electrode) and the donor layer, and a I nm thick LiF layer can be added between the acceptor layer and the negative electrode layer (such as an Al electrode) in order to enhance carrier collection at both electrodes. In practice, it is desirable and also critical that, when depositing (either spin coating or drop drying) the second donor layer on top of the first PSS/PEDOT layer, the solvent dissolving the donor will not dissolve the dried PSS/PEDOT layer. The same principle is also applicable for the third block copolymer layer in reference to the second donor layer, and to the fourth acceptor layer in reference to the -DBAB- block layer, and so on. One major advantage of this second photovoltaic cell is that the added donor and acceptor layers would create a desire asymmetry (or photo-induced chemical potential gradient) in the photoactive medium itself (without electrodes), so that even if the two electrodes are the same, asymmetric voltage or current would still be generated by light radiation where the donor layer side would gather more photo-generated holes and therefore constitute the positive electrode side, and the acceptor layer would be rich in photo-generated electrons and therefore constitute a negative electrode side.
[0062] Another device or aspect is a tandem style photovoltaic device (or PV cell) structure, as shown in FIGS. 14 and 15 , which includes plural or multiple superposed block copolymer sub-cells forming a tandem stack and preferably serially connected.
[0063] The tandem stack is an efficient configuration. For the purposes of this application, “incident” refers to the incoming radiation, light, or photons, such that an “incident” sub-cell is a sub-cell that first receives the incident light or radiation. The word “residual” refers to the radiation, light, or photons passing out of a sub-cell, such that a residual sub-cell receives residual light or radiation from a sub-cell earlier in the light propagation path. Of course, there preferably would be multiple residual sub-cells, with one final residual sub-cell Multiple incident sub-cells, though feasible, would not be preferable because the stack may be mis-aligned with respect to the incident radiation, which in many cases would decrease efficiency. As shown in FIG. 14 , a plurality of block copolymer sub-cells may be superposed with respect to each other to form a tandem stack having an incident sub-cell and at least one residual sub-cell. This tandem device may be sandwiched between a transparent electrode (T-ET) superposed onto the exposed incident side of the otherwise incident sub-cell and a transparent or opaque electrode (TO-ET) superposed onto the exposed final or far side of the residual sub-cell, as shown in FIG. 14 .
[0064] For this aspect of the invention, a sub-cell, as shown in the embodiment in FIG. 15 is based on the block copolymer, and may comprise two different materials (or phases), one is the p-type semiconductor or organic/polymeric donor type material, and the other is an n-type semiconductor or organic/polymeric acceptor type material. The word “transparent” simply means capable of passing a desired quantity, and type of light for the application of interest; thus, transparent could encompass a wide variety of transparent or semi-transparent materials or designs.
[0065] The two materials (or phases) are preferably assembled in a way as shown in FIG. 15 , i.e., in a binary inter-mixed ‘columnar’ type morphology sandwiched un-symmetrically between a p-type (or donor) thin layer and a n-type (or acceptor) thin layer, where the diameter of each column should preferably not be substantially longer then the average exciton diffusion length (AEDL). The-AEDL is defined as the average distance a photo excited exciton travels before relaxing back to ground state. Such an un-symmetrically sandwiched ‘columnar’ type morphology may be achieved by a number of methods, such as using -donor-bridge-acceptor-bridge- type conjugated block copolymers as described above, or other binary nano structure fabrication methods, such as those described by B. Sager, et al. in U.S. Pub. No. 2004-0250848, by J. Whiteford, et al. in U.S. Pub. No. 2004-0146560, by M. Roscheisen in U.S. Pub. No. 2005-0098204, by B. Sager, et al. in U.S. Pub. No. 2005-0121068, etc., all of which are incorporated by reference. The sub-cells are preferably serially connected and stacked to each other as shown in FIG. 14 , and with P— (or N—) terminal layers facing the same direction. Additionally, a thin transparent (or semi transparent) and conductive layer (TCL) is preferably interposed between each of the sub-cell units. A wide variety of transparent and conductive materials may be used including, but not limited to, a thin layer of gold or ITO glass. The side directed to incident radiating light includes the transparent electrode or T-ET superposed on the exposed incident side of the incident sub-cell, which is followed by the residual sub-cells as shown in FIG. 14 . Thus, the T-ET is superposed onto the incident sub-cell and is configured to receive incident electromagnetic radiation, pass the electromagnetic radiation to the incident sub-cell, and collect charged carriers from the incident sub-cell. The TO-ET is superposed onto the exposed far side of the final residual sub-cell and is configured to collect charged carriers from the final sub-cell.
[0066] Energy gap grading may be used to improve efficiency. Typically, in each sub-cell, the donor or acceptor has only one energy gap and can only efficiently capture a narrow or limited range of energy matched photons. A tandem configuration enables the ordering or grading of average excitation energy gaps among the plurality of sub-cells to span a broader range of the energy spectrum. Starting from the T-ET side to the TO-ET side (i.e., the incident sub cell and moving in the direction of light propagation along the sub-cells), the average excitation energy gap of each sub-cell (i.e., defined as the average value of the optical excitation energy gaps of both the donor and the acceptor) is graded or configured in generally descending order—from larger energy gap (i.e., at the incident sub-cell) to smaller energy gap (i.e., along the residual sub-cells). The range of the grading of sub-cell energy gaps preferably approximates the range of the electromagnetic radiation for the PV device to be used. For instance, the solar photon flux energy spectrum defines a maximum energy level of about 3 eV and a minimum energy level of about 0.5 eV. Thus, in solar cell applications the largest average energy gap of the incident sub-cell (i.e. closest to T-ET side) may be set to about 3 eV (or larger) to capture photons at the maximum, and the smallest average energy gap of the final residual sub-cell (i.e., closest to TO-ET side) may be set to about 0.5 eV (or smaller) to capture photons at the minimum. The incident sub-cell, having the largest average energy gap, would capture the highest energy matched photons first, but also would allow residual lower energy photons to pass through to the subsequent residual sub-cells having lower energy gaps, and so on. A generally decreasing average energy gap enables photon capture along the desired energy spectrum. Even if some excitons in the front or incident sub-cells having a larger average energy gap did not dissociate and relaxed to emit smaller energy photons (i.e., due to the well known stokes shift), those photons can be captured by subsequent residual sub-cells having a lower average energy gaps.
[0067] If the T-ET and TO-ET are different materials, then the p− (or donor) side of all sub-cells should generally face the direction of the electrode having the larger work function (i.e., the electrode with a more negative energy level below the vacuum energy level at zero.) The work function is defined as the average energy needed to remove one electron from the material. Additionally, the positive electrode of the device (where positively charged holes will be collected when light is radiated to the device) is the electrode where the p− or donor side of the sub-cell units are facing, and the negative electrode of the device (where negatively charged electrons will be collected when light is radiated to the device) is the electrode where the n− or acceptor side of the sub-cell units are facing.
[0068] The -donor-bridge-acceptor- type block copolymer disclosed herein is a significant difference or improvement over small molecule donor-bridge-acceptor approaches. The use of block copolymer enables secondary and tertiary structures or morphologies for improved photo charge separation and charge transport. Thus, the carrier generation and transport in each sub-cell of the tandem photovoltaic device is improved due to the ordered nano structure, as elaborated herein. Excitation energy gap grading among the stacked multiple sub-cells also enhances the ability for photon capture of broader spectrum of radiation (e.g., sunlight radiation).
[0069] This contemplated arrangement may be achieved in a variety of configurations. While there has been described what are believed to be the preferred embodiment of the present invention, those skilled in the art will recognize that other and further changes and modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the true scope of the invention.
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A -donor(D)-bridge(B)-acceptor(A)-bridge(B)- or derivative type block copolymer system used in a tandem device of multiple sub-cells, where donor (D) is an organic conjugated donor (p-type) block, acceptor (A) is an organic conjugated acceptor (n-type) block, and bridge (B) is a non-conjugated and flexible chain, has been designed and preliminarily tested for potential lightweight, flexible shape, cost-effective and high efficiency “plastic” thin film solar cell or photo detector applications. A ‘tertiary supramolecular nanophase separated structure’ derived from this -DBAB- block copolymer is expected to improve opto-electronic (photovoltaic) power conversion efficiency significantly in comparison to all existing reported organic or polymeric donor/acceptor binary photovoltaic systems due to the reduction of “exciton loss,” the “carrier loss,” as well as the “photon loss” via three-dimensional space (morphology) and energy level optimizations. The tandem stacking of block copolymer sub-cells further enables optical excitation energy gap grading to improve photon capture of solar spectrum and device efficiency.
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CROSS-REFERENCE TO RELATED APPLICATION
The present application claims priority from Japanese Patent Application No. JP 2010-041999 filed in the Japanese Patent Office on Feb. 26, 2010, the entire content of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a filter device and a projector apparatus having such a filter device. More particularly, the invention relates to a filter device required for taking in external air and to a technique used in a projector apparatus having such a filter device.
2. Description of the Related Art
An electronic apparatus according to the related art such as projector apparatus for projecting images have a cooling mechanism for suppressing heat generated at internal processing sections as a result of operations of the apparatus by taking external air into the apparatus to cool the same.
When an apparatus takes in cooling air, the external air is sent to a filter to remove particles of dust in the same, and the air is thereafter taken into the apparatus. Particles of dust are removed from air with a filter as thus described to prevent the entry of particles of dust which can adversely affect the apparatus.
A filter of the type described above must receive maintenance such as cleaning or replacement each time the apparatus employing the filter is operated to a certain degree, and the filter is therefore constructed such that it can be inserted and removed in and from the apparatus.
Mechanisms for inserting and removing a filter in and from a projector apparatus according to the related art include relatively simple mechanisms formed by an external air intake port and a filter covering the same, a frame-like element formed by the external air intake port and the filter holding the same serving as an inserting/removing mechanism.
There are alternative mechanisms in which a frame member holding a filter is slid into an apparatus from a side of the body of the apparatus and in which the filter is disposed in the middle of a duct provided in the apparatus for taking external air into the apparatus. When such a mechanism is used in a projector apparatus, there is no need for disposing a filter at an external air intake port which is visible on the exterior of the apparatus. Therefore, the mechanism allows the filter to be inserted and removed in and from the apparatus while allowing the apparatus designed with relatively good appearance.
JP-A-10-186513 (Patent Document 1) discloses an exemplary projector apparatus in which a filter 241 is disposed to be attachable to an air intake port as shown in FIG. 3 accompanying the document.
SUMMARY OF THE INVENTION
In order to improve the efficiency of cooling utilizing external air in the above-described type of apparatus, it is required to increase the size of an eternal air intake port and to increase the surface area of a filter. However, when an excessively large filter is used, the problem of degradation of operability arises when the filter is inserted and removed in and from an apparatus. The use of a large filter is preferable in that the filter is less likely to undergo clogging and the cycle of cleaning of the filter can be extended. However, measures must be taken to dispose a large filter properly.
For example, in the case of the above-described mechanism in which a frame member holding a filter is slid into an apparatus from a side of the body of the apparatus to house the filter inside the apparatus, if the filter has a great size in the longitudinal direction thereof, the filter can hit a wall and the like when it is pulled out from the apparatus. Projector apparatus are mostly fixed to a predetermined location in a room, e.g., the ceiling of the room when they are used. In the case of a projector apparatus fixed along a wall, a filter pulled out from the apparatus for the purpose of maintenance may interfere with the wall, and the replacement of the filter may be disabled in some cases. Therefore, the apparatus must be installed at such a distance from the wall that filter replacement can be carried out. However, when a filter of a greater size is used, the distance at which the apparatus must be spaced from the wall to allow filter replacement increases accordingly, which has been problematic in that there are increased limitations on the installation of the apparatus.
Under the circumstance, it is desirable to reduce limitations placed on the replacement of a filter for taking external air into an apparatus.
According to an embodiment of the invention, there is provided a filter device to be used in an apparatus having an intake port for taking external air into the body of the apparatus.
The filter device includes first and second filter elements allowing air taken in through the intake port to pass therethrough and first and second filter holding members holding the first and second filter elements such that they are linearly connected side by side, the holding members being connected to be foldable in the position where the filter elements are connected.
A projector constituting the apparatus body has a filter insertion hole through which the first and second filter holding members are slid in the direction of the linear alignment between them. Thus, the filter holding members can be contained in the apparatus body.
In such a configuration, when the first and second filter holding members are inserted through the filter insertion hole, one of the filter holding member can be inserted with the other filter holding member folded. It is therefore possible to insert and remove the filters in and from the apparatus for the replace and cleaning of the filters if a space having a length equal to or greater than the length of one filter holding member is available beside the apparatus body.
According to the embodiment of the invention, one of the filter holding member can be inserted with the other filter holding member folded. The filters can be replaced or cleaned if a space having a length equal to or greater than the length of one filter holding member is available beside the apparatus body. Therefore, the space required for the installation of an apparatus body can be smaller than that in the related art, and limitations placed on a space where an apparatus body is to be installed are relaxed compared to limitations placed according to the related art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a projector apparatus according to an embodiment of the invention showing an exemplary general configuration thereof;
FIG. 2 is a perspective view of the projector apparatus according to the embodiment of the invention showing a filter member partially inserted therein;
FIG. 3 is a side view of the projector apparatus according to the embodiment of the invention in the state shown in FIG. 2 ;
FIG. 4 is a perspective view of the projector apparatus according to the embodiment of the invention showing an exemplary internal configuration thereof;
FIG. 5 is a perspective view of the projector apparatus according to the embodiment of the invention showing the exemplary internal configuration thereof;
FIG. 6 is a perspective view of a filter member according to the embodiment of the invention showing an exemplary configuration thereof; and
FIG. 7 is a partially exploded perspective view of the filter member shown in FIG. 6 .
DESCRIPTION OF PREFERRED EMBODIMENTS
Embodiments of the invention will now be described. The following items will be described in the order listed.
1. Overall Configuration of Projector Apparatus ( FIGS. 1 to 3 )
2. Configuration of Filter ( FIGS. 6 and 7 )
3. Flow of Air taken through Air Intake Port ( FIGS. 4 and 5 )
4. Modifications
[1. Overall Configuration of Projector Apparatus]
FIG. 1 is an illustration showing an overall configuration of a projector apparatus according to an embodiment of the invention.
The present embodiment is a projector apparatus which displays an image as follows. An optical block provided in the apparatus irradiates a display panel with light from a light source. Image light (projection light) of an image to be displayed formed by transmitting or reflecting the light from the light source at the display panel is projected on a screen through a projection lens to display the image.
As shown in FIG. 1 , a projection lens 11 is mounted on a front end of the body of a projector apparatus 10 , the body being formed by a box-like housing. Projection light exits the projection lens 11 .
FIG. 1 shows one side face and a rear end of the projector apparatus 10 . Two air intake ports 12 and 13 are disposed on the side face such that they extend side by side in the horizontal direction. Air taken through the air intake ports 12 and 13 blows on an optical block in the projector apparatus 10 as a cooling air flow. The intake air is passed through filters 31 and 32 mounted to a filter member 20 as shown in FIG. 1 (the filter 31 is not shown in FIG. 1 ), although details of the configuration for passing the intake air will be described later. The filter member 20 is shown outside the apparatus in FIG. 1 .
The filter member 20 of the present embodiment has an elongate shape, and the member is formed by connecting two filter holding portions, i.e., a first filter holding portion and a second filter holding portion 22 into a straight shape at a connecting portion 26 . One of the filter holding portions can be folded toward the other filter holding portion at the connecting portion 26 . A specific configuration of the filter member 26 will be described later.
A cover 14 is mounted to a rear end 15 of the body of the projector apparatus 10 . The cover 14 is shown apart from the apparatus body in FIG. 1 . As shown in FIG. 1 , a filter insertion hole 16 is exposed by removing the cover 14 . The filter member 20 formed by connecting two filter holding portions into a straight shape is linearly inserted into the filter insertion hole 16 from one end 20 a thereof. When the filter member 20 has been completely inserted into the filter insertion hole 16 , another end 20 b of the filter member 20 is exposed at the filter insertion hole 16 . A grip portion 28 is provided at the end 20 b , and a maintenance worker can remove the filter member 20 by pulling out the filter member 20 with the grip portion 28 held by his or her fingers.
FIG. 2 shows a state in which the filter member 20 has been inserted into the filter insertion hole 16 halfway (the second filter holding portion 22 has been inserted halfway).
As shown in FIG. 2 , when only the second filter holding portion 22 is inserted with the first filter holding portion 21 kept outside the filter insertion hole 16 , the first filter holding portion 21 can be folded upward about the connecting portion 16 serving as a fulcrum.
FIG. 3 is a side view of the apparatus in the same state as shown in FIG. 2 , and FIG. 3 shows a state in which the first filter holding portion 21 is folded and lifted upward.
Therefore, as shown in FIG. 3 the filter member 20 can be replaced with new one when a distance L from the rear end 15 of the projector apparatus 10 to a wall 90 exceeds half of the length of the filter member 20 (or the length of each of the filter holding portions 21 and 22 ) even in a small amount.
[2. Configuration of Filter]
An exemplary configuration of the filter member 20 of the present embodiment will now be described with reference to FIGS. 6 and 7 .
FIG. 6 is a general perspective view of the filter member 20 , and FIG. 7 shows an exploded view of the second filter holding portion 22 with the first filter holding portion 21 shown in an assembled state. The first filter holding portion 21 and the second filter holding portion 22 have the same configuration for holding the filter, the configuration being shown in the exploded view of the second filter holding portion 22 in FIG. 7 .
As shown in FIG. 6 , the filter member 20 is formed by connecting the first filter holding portion 21 and the second filter holding portion 22 at a connecting portion 26 such that holding portions are integrated to extend straightly, each of the holding portions being formed from a resin. The connecting portion 26 is a bendable and rotatable connecting portion, as described above. Specifically, as shown in FIG. 6 , the connecting portion 26 is formed by connecting an end 21 a of the top surface of the first filter holding portion 21 with an end 22 a of the top surface of the second filter holding portion 22 using a resin film having a thickness smaller than the thickness of the regions of the holding portions surrounding the same. Since the connecting portion 26 has a small thickness as thus described, the first filter holding portion 21 and the second filter holding portion 22 can be folded toward each other.
For example, as indicated by the arrow X in FIG. 6 , the filter member 20 can be folded such that one end 20 b of the filter member 20 is put in contact with another end 20 a of the same.
When the filter member is folded such that the top surface of the first filter holding portion 21 is put into contact with the top surface of the second filter holding portion 22 , an engaging part 29 a provided at the end 20 a engages an engaging part 29 b provided at the other end 20 b to keep the member in the folded state. That is, the engaging parts 29 a and 29 b serves as anchoring mechanism parts for holding the first filter holding portion 21 and the second filter holding portion 22 in a lapped state.
When a filter member 20 is transported to be mounted to an apparatus or to be used as a replacement for maintenance, the member can be transported in such a folded state. The elongate filter member 20 can be transported with its length shortened as thus described.
When the first filter holding portion 21 and the second filter holding portion 22 are arranged in the straight state as shown in FIG. 6 , an end of a protrusion 21 b of the first filter holding portion 21 and an end of a protrusion 22 b of the second filter holding portion 22 abut on each other in a position lower than the connecting portion 26 . The abutment between the ends of the protrusions 21 b and 22 b regulates the first filter holding portion 21 and the second filter holding portion 22 to prevent the holding portions from being folded in the opposite directions. Specifically, although the first filter holding portion 21 can be folded or lifted upward as indicated by the arrow X, the first filter holding portion 21 can not be folded downward.
Ribs 27 are provided on both lateral surfaces of each of the first filter holding portion 21 and the second filter holding portion 22 of the filter member 20 . FIGS. 6 and 7 show the ribs 27 provided on one side of the filter holding portions with the ribs on the other side omitted.
When the filter member 20 is inserted into a filter insertion hole 16 as shown in FIG. 1 , the ribs 27 fit in grooves 16 a provided on the duct section 70 as will be described later to allow the filter member 20 to be slid linearly.
The mechanism of the first filter holding portion 21 and the second filter holding portion 22 for holding filters 31 and 32 will now be described with reference to FIG. 7 . As described above, the first filter holding portion 21 and the second filter holding portion 22 hold the filters 31 and 32 using the same configuration. The disposition of a filter in the second filter holding portion 22 will now be described with reference to FIG. 7 , and the description completely applies to the first filter holding portion 21 .
As shown in FIG. 7 , a holding frame 23 is provided at the bottom of a frame made of resin which constitutes the second filter holding portion 22 , and the filter 31 is supported by the holding frame 23 at a bottom surface thereof.
The filter 31 , which is constituted by a sponge-like resin sheet or nonwoven fabric, is placed on the holding frame 23 .
The filter 31 has holes 31 a provided in four positions near edges thereof, and protrusions 24 provided on the holding frame 23 in four inward positions thereof (only two locations are shown) are inserted into the holes 31 a of the filter 31 to secure the filter 31 in place.
A frame-like spacer 40 constituted by a resin member is disposed on the filter 31 , and the filter 32 is disposed on the spacer 40 . The filter 32 is also constituted by a sponge-like resin sheet or nonwoven fabric, but the filter 31 is formed from a material having finer pores through which are is allowed to pass when compared to the filter 32 .
The filter 32 also has holes 32 a provided at four corners thereof, and protrusions 41 provided at four corners of the spacer 40 are inserted into the holes 32 a of the filter 32 to secure the filter 32 in place.
Further, a presser member 50 is placed on the filter 32 to press the top surface of the filter 32 . The presser member 50 has three protrusions 51 provided in three positions on each side thereof, and the protrusions 51 are engaged with respective anchoring parts 25 provided in six locations on side faces of the body of the second filter holding portion 22 to secure the presser member 50 , whereby the filters 31 and 32 are secured in place.
Two filters 31 and 32 are disposed in each of the first filter holding portion 21 and the second filter holding portion 22 such that the filters are spaced from each other at a predetermined interval. Thus, particles of dust included in air taken from the outside are removed by the four filters in total.
[3. The flow of Air from Intake Ports]
The flow of air taken in through the air intake ports 12 and 13 shown in FIG. 1 will now be described with reference to FIGS. 4 and 5 .
FIG. 4 is an illustration showing the external shape of the optical block 60 in the projector apparatus 10 and showing a duct section 70 disposed beside the optical block 60 . The external shape of the projector apparatus 10 (the shape of the housing) is represented by an imaginary line (two-dot chain line). A filter member 20 is horizontally disposed in the duct section 70 shown in FIG. 4 . FIG. 5 shows the configuration of the apparatus with the duct section 70 omitted (to show the filter member 20 ).
As shown in FIG. 4 , the duct section 70 has a plurality of openings 73 provided in series on a side of the same associated with the position where the air intake ports 12 and 13 show in FIG. 1 are disposed, and the filter member 20 is disposed at the bottom of the duct section 70 .
Further, two Scirocco fans 71 and 72 are disposed under the filter member 20 to cause air filtered through the filter member 20 to blow on the bottom of the optical block 60 disposed adjacent to the duct section. The two Scirocco fans 71 and 72 blow external air on a part of the optical block 60 where a display panel section 62 is disposed, i.e., a heat-generating part of the optical block 60 to cool the part. In the present embodiment, three display panels are disposed to form the display panel section 62 , and the two Scirocco fans and 72 supply air to the three display panels in cooperation with each other. Air is also supplied from the Scirocco fans 71 and 72 to a light source section 61 , which is another heat-generating part of the optical block 60 , to cool the section.
As will be apparent from the disposition of the filter member 20 illustrated in FIG. 5 , the two Scirocco fans 71 and 72 are disposed directly under the filter member 20 . Therefore, external air taken in through the openings 73 of the duct section 70 (or the air intake ports 12 and 13 ) reaches the Scirocco fans 71 and 72 after passing through the four filters 31 and 32 of the filter member 20 . Thus, the air is supplied to the Scirocco fans 71 and 72 with particles of dust removed from the same.
As described above, in the projector apparatus 10 of the present embodiment, filters having a relatively large surface area are disposed as filter for cleaning cooling air, whereby a filter member 20 extending substantially the entire length of the side face of the apparatus is formed. Operations of mounting and removing the filter member 20 in and from the apparatus can be carried out in a small space.
Specifically, since the filter member 20 can be folded in the middle thereof as shown in FIGS. 2 and 3 , the filter member can be replaced with new one even when a wall 90 exists near the rear end of the apparatus if a distance L that is substantially equivalent to one half of the length of the filter member 20 is left between the apparatus and the wall.
The use of large filters allows cleaning and maintenance operations to be carried out at longer intervals, and the space required around the projector apparatus 10 to perform such operations can be small. Thus, the embodiment is advantageous in that limitations placed on a space for installing the main body of the projector apparatus can be relaxed when compared to the related art.
The first filter holding portion 21 and the second filter holding portion 22 of the filter member 20 are made foldable toward each other by a simple resin feature having a small thickness connecting the holding portions 21 and 22 . Therefore, the connecting portion can be formed at the same time when the holding portions 21 and 22 are molded from a resin. This is advantageous in that the connecting portion for allowing the filter member to be folded can be formed simply at a low cost.
When the filter member 20 is transported to be mounted to an apparatus or to be used as a replacement for maintenance, the member can be folded to halve the length thereof as indicated by the arrow X in FIG. 6 . Thus, the elongate filter member 20 can be transported with its length shortened as thus described, and the transportation of the filter member 20 can be carried out with improved operability.
Further, since the filter member 20 is constructed so as to be easily locked in the folded state by the engaging portions 29 a and 29 b , particles of dust deposited on the filters 31 and 32 can be confined in the filter member. It is therefore possible to prevent particles of dust from scattering when the filter member 20 is removed from the projector apparatus 10 for transportation.
The two filters 31 and 32 held by the holding portions 21 and 22 of the foldable filter member 20 are disposed at an interval from each other, and the material of the filters 31 and 32 are different in coarseness. Large particles of dust are removed when eternal air first passes through the filter 32 , and smaller particles of dust are thereafter removed by the finer filter 31 . Thus, the embodiment is advantageous in that the air filters are capable of cleaning air with very high efficiency. In addition, since the filter member 20 including the two filters 31 and 32 having a relatively great surface area can be folded compactly as thus described, the filter member can be efficiently operated.
[4. Modifications]
While the above-described embodiment is an application of the invention to a filter for cleaning cooling air for a projector apparatus which projects images, the invention may be applied to other types of electronic apparatus which must take external air into themselves.
FIG. 1 and other figures merely show an exemplary position of the insertion hole at which the filter member is inserted into the body of an apparatus such as a projector apparatus and exemplary positions of air intake ports,
The configuration in which each of the filter holding portions 21 and 22 holds two filters 31 and 32 is also merely an example. Each filter holding portion may alternatively be configured such that only one filter is disposed therein.
Although the filter member 20 of the present embodiment is configured to be folded halfway at one folding position, two or more folding positions may alternatively be provided.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
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A filter device which may include first and second filter elements allowing air to pass therethrough, and first and second filter holding members holding the first and second filter elements such that they are linearly connected side by side. The holding members being connected to be foldable in the position where the filter elements are connected.
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This application is a continuation of application Ser. No. 08/249,018 filed May 26, 1994, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to a method of manufacturing an electroformed tool, especially, a method of manufacturing an electroformed tool suitable as a mold to form plastic.
PRIOR ART
Conventionally, tools for plastic blow-molding or vacuum forming, etc. have numerous minute holes to release gas coming out of a parison which is forming material or a heated sheet or air in the tools.
Concerning methods to make the holes, available are methods such as a mechanical one to make holes by a minute drill, etc. after making a tool, or an electric-chemical method to make a tool by means of electroforming, etc., that is able to form a porous electrodeposited layer in order to have a tool itself made of a porous substance, and so forth.
However, the former method is not very preferable because it is too costly and requires too much time due to the very troublesome work to make many minute holes. On the other hand, the latter method is better in terms of cost and time because a tool becomes porous in its manufacturing process. But, due to the features of its manufacturing process, the process has defects such that the formation and shape of the holes are uncertain, that the walls around the holes tend to be thin or that strength enough for a tool cannot be obtained because material containing fine bubbles tends to be deposited and by other reasons.
Further, even if it bears usage as a tool, there is another problem that it is very difficult to repair if damaged during use.
In the Japanese laid open patent specification HEI5-156486, a method of manufacturing an electroformed tool with many air-releasing holes formed by an electroforming method is disclosed. In this method, a mother tool on which holes are created in advance is used as a cathode or a negative pole and electroforming operation is done by electroforming solution substantially without a surface-active agent. The idea is to make it easy to keep hydrogen gas coming out at the time of electrodeposition in a non electrically-conducting part made by piercing holes in a mother tool in advance and, by doing so, to let holes grow as holes, without adding a surface-active agent, such as sodium laurylsulfate which conventionally has been added to suppress pin hole growth.
However, it is important there be uniformity of thickness to manufacture an electroformed tool. Because of this, in a proper time during the manufacturing process, a tool is taken out of the electroforming solution and the thickness of the electrodeposited part is measured. After masking the part that has already reached the predetermined thickness, the tool is put into the electroforming solution again and the electroforming operation is repeated. This kind of operation is usually repeated five times. The number of times increases or decreases, depending on a shape of the tool.
However, in the case where electrodeposition is resumed by putting a tool into the electroforming solution after masking the work, holes have indeed hollow parts and are formed as holes by electrodeposition at the early stage of this electrodeposition. But, because the hollow parts are not non electrically-conducting parts when electrodeposition is resumed due to non-existence of hydrogen gas collection, and the holes slowly become smaller by the leveling function of the electroforming solution. In this way, repetition of masking the work tends to cause the phenomenon that the holes finally disappear. Therefore, problems are inevitable in this method, as they are in the method to make holes in the electroformed tools by a drill, etc.
Further, this electrodeposition method does not solve the problem, in that it tends to be a vulnerable deposited material containing minute bubbles of hydrogen gas by the leveling function of the electroforming solution because the method is to maintain and grow the holes made on the mother tool in advance, by means of hydrogen gas coming out in the process of electrodeposition.
THE PROBLEMS THAT THE INVENTION IS GOING TO SOLVE
Therefore, the purpose of this invention is to provide an easy and convenient method of manufacturing a porous tool by a new electroforming method free from the problems that are found in a porous tool manufactured by a conventional electroforming method, such as lack of strength and non-uniformity of air-releasing hole systems and shapes.
MEANS TO SOLVE THE PROBLEMS
The inventors discovered that what is called a pit (non-electrodeposited part) could be very easily formed and certainly grown by adding a non-leveling agent to the electroforming solution in the process of electroforming on the electrically-conducting part formed on the insulating base formed in the shape of prototype, and created this invention.
Namely, this invention, in the broadest sense, pertains to a method of manufacturing an electroformed tool in which the metal electrodeposited layer is formed by depositing metal on the base by electroforming, characterized by using electroforming solution to which is added a non-leveling agent during the process of depositing metal on the base.
Furthermore, to be more specific, this invention pertains to a method of manufacturing an electroformed tool having an electrodeposited metal layer with a non-electrodeposited portion by preparing an electrically-conducting base or a non-electrically-conducting base, in which, in case of the non-electrically-conducting base, an electrically-conducting layer is provided on the surface of the base and then metal is deposited on said base by electroforming, using electroforming solution to which is added a non-leveling agent.
Here, since "non-leveling agent" has a function to reduce horizontal growth of plating electrodeposition and positively grow electrodeposition in a vertical direction in the sense of thickness by working on the leveling ability of the electrolytic plating solution, it functions to grow non-electrodeposited parts created by various factors at the early stage of electrodeposition (the cause of pit growth) as holes during electrodeposition, without plugging them.
By the way, the "surface-active agent" functions, by absorbing molecules of a solid body or liquid to enhance permeability or water affinity of the object to be electrodeposited and the electrolytic plating solution, and to make it easier for the electrolytic solution to get into minute portions of the electrodeposited surface. Concurrently, it functions to promote removal of the air film attached to the surface of the object to be electrodeposited at the early stage of electrodeposition or hydrogen gas attached to the electrodeposited surface created by the electrolytic reaction.
Further, in this invention, the physical property or mechanical strength of electrodeposited metal can be improved, since minute bubbles of hydrogen gas can be kept from remaining in the electrodeposited metal layer, by using a proper amount of surface-active agent as well and promoting removal of hydrogen gas created in the process of electrodeposition apart from the electrodeposited surface.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a view showing the manner of growth of an electrodeposited layer and pits (non-electrodeposited layer) when electroforming is done by electroforming solution to which was added a non-leveling agent, according to this invention.
FIG. 2 is a view similar to FIG. 1 showing a preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The effect of the invention is specifically explained below.
In order to work the manufacturing method related to this invention, first, a base which is formed in a shape of a prototype is prepared. The material constituting this base may be either electrically-conducting or non-electrically-conducting and it is not particularly limited. As stated below, since the base will be removed from the electroformed body, inexpensive material, for example, plastic material to be easily formed in a predetermined shape, such as epoxy resin, polyester resin, phenol resin, urea resin, etc. is preferable, unless it is to be reused.
Therefore, this base is formed of, for example, epoxy resin, etc. in the predetermined surface shape of, for example, an automotive door trim, etc. by utilizing the reverse tool, etc. of the product model.
Next, the invention is more specifically explained by taking as an example the case when epoxy resin, which has a non-electrically-conducting property, is used as the material to constitute the base.
Since epoxy resin naturally has insulating properties, it forms a continuous film of an electrically-conducting layer by utilizing a silver mirror reaction, which is a sort of silver chemical plating on the surface to be covered or by painting electrically-conducting painting material such as silver lacquer, etc. Further, when silver mirror reaction is used on an electrically-conducting layer, it is preferable to do an oil-removing treatment on the surface of the base to be covered prior to formation of this electrically-conducting layer in order to enhance adhesive power of the electrically-conducting layer to the base, and to enhance sensitivity by painting stannous chloride solution, and so forth.
The base provided with an electrically-conducting layer on its surface is inserted into an electroforming tank filled with electrolytic plating solution constituting a predetermined composition including non-leveling agent, and the electrically-conducting layer of said base becomes a cathode or a negative pole, while the other pole which is a positive pole is constituted by things such as a metal plate made of the same metal as the one to be electrodeposited, and the electroforming is conducted by adding the predetermined voltage between both poles.
Usually, in order to prevent pits, an oxidated film on the surface of the electrically-conducting layer is chemically removed and activated, and further, prior treatment such as adding water affinity by pouring water solution of surface-active agent is provided before insertion into the electroforming tank. In this invention, it is preferable to insert with the dried electrically-conducting layer surface into an electroforming tank, without conducting the prior treatment in order to positively create pits.
In addition, formation of pits is caused by the extent of a sort of insulating destruction phenomenon at the time of electrodeposition to the oxidated film by air oxidation formed on the surface of said electrically-conducting layer formed as explained above, the extent of removal of the air film attached to the surface of the electrically-conducting layer at the time of soaking into the tank, or non-successive parts such as partial subtle hollows existing on the surface and so forth. This is also promoted by the attachment of hydrogen gas, which is created by the gaps of hydrogen overvoltage between electrically-conducting layer metal and electrodeposited metal, or the attachment of dust in the electrolytic solution (minute foreign substance) and so forth. Certainly, a base can have many minute holes on it by a mechanical means such as using a drill, etc.
Further, in order to form pits more easily (non-electrically-conducting parts), hydrophobic non-electrically-conducting particles such as polytetrafluroethylene (PTFE), etc. may be sprayed or combined with the resin in advance.
In case of using an electrically-conducting base, it is not necessary to provide another non-electrically-conducting layer, as far as only electrically-conductive as a cathode or a negative pole is considered. An electroformed tool is used with its electrodeposited metal part separate from the base. Thus, considering convenience of separation, it is preferable to provide an electrically-conducting layer surface such as silver mirror reaction, as in the case of non-electrically-conducting base.
Electroforming operations themselves can be conventional ones as well as the composition of electrolytic plating solution, except for using non-leveling agent. The electroforming operations are not limited at all.
As an electroforming process progresses, formed non-electrodeposited parts (pits) grow by existence of minute remaining parts of oxidated film on the base surface or minute hollows on the base surface and are stably reserved and grow in accordance with the growth of the electrodeposited metal layer by adsorbing effect of the non-leveling agent.
Specific kinds of non-leveling agents used in this invention are explained as below.
The non-leveling agent used in this invention functions to control activation against diffusing control by the leveling agent at the time of electrodeposition. The composition of the non-leveling agent comprises a proper amount of benzenesulfonic acid or its derivatives, carboxylic acid or its salt such as formic acid or hemimellitic acid, nicotinic acid or its derivatives such as nicotinamid, methyl-pentynol and its derivatives, etc. Preferable non-leveling agents are benzenesulfonic acid, carboxylic acid, nicotinic acid and methyl-pentynol. Due to activation control, because electrodeposited metal crystallization and growth progress in the vertical direction of the base and rarely progress in the horizontal direction, non-electrodeposited parts remain as they are.
Namely, as illustrated in FIG. 1, by this invention, pits 12 formed on the base 10 at the initiation of electroforming are, by the function of the non-leveling agent, reserved stably and continue to grow in accordance with the formation of the electrodeposited metal layer 14. FIG. 1 shows how the pits 12 on the surface of a cathode or a negative pole grow.
In this way, when a non-leveling agent is combined with electrolytic solution by this invention, since electrodeposition has activation control by its function, plating is continued with the shape of the original plated surface as it is, that is, with plating metal not diffused on the pits, and the bottoms of minute hollows which is hard to reach by current are difficult to be plated, and this tendency is intensified as the thickness of the plate increases. Despite the growth of the plating layer, non-electrodeposited parts remain as they are.
In the preliminary examination to eliminate leveling property of plating electrolytic solution done by the inventors, by adding benzenesulfonic acid or carboxylic acid as a non-leveling agent to the nickel electrolytic solution of the standard composition, within the range of 0.05-0.8 g/L additive amount, uniform electrodeposition was made available without at all losing grinded surface on a brass plate made by No. 800 sand paper.
Further, when nicotinic acid derivative or methyl-pentynol and its derivatives and so forth are used, the same result was obtained within the range of 0.001-0.1 g/L additive amount.
In the preliminary examination to obtain a porous electroformed body, by the effect of non-leveling agent, non-plated parts created by hydrogen gas which was created and attached to the silver mirror surface at the early stage of electrodeposition remained as they were and other plated parts grew and non-plated parts remained as pits and a porous electroformed body was obtained. In this condition, electroforming was carried out for several days and a porous electroformed tool is formed. Since an electroformed tool manufactured in the above manner has enough air permeability, it may be used for plastic tooling. In order to improve strength, a back-up layer can be provided for supplemental strength.
According to the preferable embodiment of this invention, aqueous colloid solution of hydrophobic non-electrically-conducting particles, for example, fine particles of plastic, such as PTFE, etc. by using a surface-active agent, can be mixed into an electrolytic solution tank.
Fine particles, such as PTFE, added in the electrolytic solution are diffused into the liquid by effect of a surface-active agent and the stirring of the electrolytic solution, and a part of them attach to the electrodeposited surface of the base. Since the diffusion and dispersion of the fine particles are done uniformly, attachment to the electrodeposited surface of the base is done almost entirely uniformly. Therefore, by adjusting the amount of the fine particles to be mixed, attachment density to the electrodeposited surface can be adjusted.
In this way, in the case of the above embodiment, since fine particles existing in the condition that they are attached to the electrodeposited surface, namely, the first electrodeposited metal layer are insulators, metal ions are not electrodeposited to the part and the part starts becoming the hollow part of the electrodeposition. When fine particles further attached are insulators and concurrently hydrophobic, hydrogen gas inevitably created at the time of electrodeposition tends to attach to the part, and, as a result, it starts growing as a larger pit than that on the porous electrodeposited metal layer in the lower layer.
FIG. 2 shows the constitution of the electrodeposited metal layer at this time. Pits 12 grown as illustrated in FIG. 1, grow bigger and form enlarged pits 20, forming the second electrodeposited metal layer 18 on the first electrodeposited metal layer 14.
Since non-electrically-conducting particles, such as fine particles of PTFE used in the above embodiment, are, as described above, diffused uniformly into the electrolytic solution, they attach to the entire electrodeposited surface of the base and pits are created in each part and from the entire view, the second electrodeposited metal layer having a uniform continuous air permeable structure is formed during the ordinary electrodepositing process, which is desirable.
The thickness of the second electrodeposited metal layer which is electrodeposited in the above manner is not particularly limited, but generally, about 2/3 to 3/4 of the entire thickness seems to be sufficient.
In this way, in an electroformed tool manufactured according to this invention, the manufactured surface of an outer surface which is an electrodeposited metal layer is a porous electroformed layer by the promoting effect of the non-leveling agent. This porous electroformed layer is something on which numerous, what is called plated pits occurred, and parts other than the pits are the ordinary plating film and the manufactured surface has enough strength. In the case where said second electrodeposited metal layer is further formed, depending on necessity, a predetermined porous tool which can be used as it is obtained, since a two-layered porous electrodeposited layer is formed during the process.
EMBODIMENT
Next, embodiments of this invention are enumerated. It should be understood that these are shown as mere examples of this invention and this invention is not limited by the embodiments.
EMBODIMENT 1
A base having a surface shape of an automotive door trim was made of epoxy resin by using a reverse tool. On the base, by an ordinary silver mirror reaction, an electrically-conducting layer comprising a silver film is formed and then is put into an electroforming tank.
The base prepared in this way was made a cathode or a negative pole. On the other hand, a nickel tip in a metal titan basket case was used as a positive pole and electrodeposition was conducted in an electroforming tank filled with electrolytic plating solution comprising the composition shown in Table 1.
The electrodepositing condition is shown in Table 1. Further, in this embodiment, the above non-leveling agent was used.
TABLE 1______________________________________Electrolytic solution to form the first layernickel sulfamate 300-400 g/Lnickel chloride 5-10 g/Lboric acid 30-40 g/Lsurface-active agent proper amountnon-leveling agent (benzenesulfonic acid) 0.1-0.5 g/LElectrodepositing conditionpH 3-4Temperature 40-50° C.Current density 0.5 A/dm.sup.2Term 4 days______________________________________
The manufactured electroformed tool was an electroformed body with 0.3-0.5 mm thickness and about 70 pits (holes) of 10-20 μm in 1 dm 2 .
EMBODIMENT 2
After finishing electroforming of embodiment 1, 0.02-0.05 g/L of PTFE particles with a diameter 5 μm was further added to the below second electrolytic solution and the electrodeposition operation was continued for 2 days. The obtained two-layer structure electroformed body had sufficient air permeability.
______________________________________Electrolytic solution to form the second layer______________________________________nickel sulfamate 300-400 g/Lnickel chloride 5-10 g/Lboric acid 30-40 g/Lsurface-active agent proper amountpolytetrafluoroethylene (PTFE) 0.02-0.05 g/L______________________________________
THE EFFECT OF THE INVENTION
As explained in detail above, an electroformed tool manufactured by this invention comprises a porous electroformed layer(s). In order to manufacture such a porous electroformed body, insulating parts to form minute holes on the electrically-conducting layer of the base are scattered in advance as in the conventional way. Non-electrodeposited parts formed by this method continue to grow as they are by adding a non-leveling agent and a predetermined strength of electrodeposited metal can be obtained, and, without plugging minute holes, the mechanical strength as an electroformed tool is enhanced.
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An electroformed tool that has a uniform air-releasing hole system with high strength and a simple and convenient method to manufacture it has been created. The method includes conducting electroforming by mixing a non-leveling agent with an electrolytic solution and forming an electroformed layer which has a continuous air-releasing hole structure.
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FIELD OF THE INVENTION
[0001] The present invention is related to controlled release preparations. Especially the invention is related to controlled release pharmaceutical preparations including active compounds having low solubility in water and to methods of preparing such preparations.
BACKGROUND OF THE INVENTION
[0002] It is known to obtain sustained release of an active substance, e.g. a pharmaceutically active powder, by embedding it in a matrix of an insoluble substance from which the active substance will gradually diffuse.
[0003] Sustained release of an active substance contained in a tablet core may also be achieved by applying to the core a semipermeable coating through which water and dissolved active substance may diffuse or an insoluble coating provided with a hole through which the active substance is released.
[0004] Gradual release of an active substance may furthermore be obtained by microencapsulating particles of an active substance in one or more layers of film which may be of different types, e.g. of a type which mediates diffusion of the active substance or release thereof in the intestines.
[0005] The dissolution of materials dM/dt in a solvent is described by the Noyes Whitney equation:
M t = AD ( Cs - C ) h
[0006] where A is the area subjected to the solvent, D the diffusion coefficient, Cs the saturation concentration, C the concentration in the bulk solution and h the thickness of the diffusion gradient. Given that convective mixing is fairly constant and that sink condition is maintained, all parameters are constant except the area that is decreasing due to the dissolution. Consequently the release rate as a function of time will depend on the geometry of the dissolving species. The dissolution of a powder is well described by the Hixson-Crowell Cube-Root Law (Martin A. Physical Pharmacy 4:th ed. Philadelphia: Lea & Febiger; 1993).
[0007] Other types of known pharmaceutical formulations having extended release are based on eroding hydrophilic matrices and the present invention concerns this type of formulations. In these formulations the release may be described by
M ( t )/ M (∞)= k·t n
[0008] where n reflects the basic kinetics of the release (Ritger and Peppas, J. Contr. Rel.5(1987)23-26). The most beneficial situation is when the release rate is independent of the fraction of substance remaining in the formulation, changes in diffusion path length or the geometry of the system (i.e. n=1).
[0009] The Hopfenberg function gives a general function describing the dissolution of different shaped objects:
M t M ∞ = 1 - [ 1 - kt C 0 r 0 ] n
[0010] where M t and M ∞ in the above formulas are the amount released at time t and infinite time, C 0 is the drug concentration and r 0 is the initial radius of the dissolving material, n is 1 for a slab of constant radius, 2 for a rod of constant length and 3 for a sphere. Constant release rate from dissolving objects can only be achieved by maintaining constant dissolving area {Robinson JR, Lee VHL. Controlled Drug Delivery, New York; Marcel Dekker; 1987, 8650}). Such systems have been suggested by coating the rim of a tablet with a water impermeable coating {Colombo P, Conte U, Caramella C, Gazzaniga A, La Manna A. Compressed polymeric minimatrixes for drug release control. Journal of Controlled Release, 1985; 1(4) 240}). Another way is to compensate for the reducing area by increasing the drug concentration in the inner parts of the system {Robinson JR, Lee VHL. Controlled Drug Delivery, New York: Marcel Dekker; 1987, 520}).
[0011] The release from an ordinary dissolving, eroding tablet is well described by
M t M ∞ = 1 - ( 1 - k r C 0 r 0 t ) 2 ( 1 - 2 k h C 0 h 0 t )
[0012] wherein Co is the concentration of drug in the matrix, r 0 and h 0 is the initial radius and height of the matrix, k r and k h are the erosion/dissolution rates of the radius and height respectively. This means that the rate of erosion/dissolution of the periphery may be different from that of the thickness due to different hydrodynamic conditions {Katzhendler, Hoffman, et al. 1997}.
[0013] The dissolution of the excipients and the structure, e.g. porosity, of the matrix will largely control the release rate from a system containing a drug with low aqueous solubility. Contrary to previous and conventional eroding/dissolving systems the present invention provides a solution to the problem of constructing a eroding/disolving system wherein the the dissolution/erosion rate increases with time so that a constant release rate of the drug over extended periods of time is attained.
OBJECTS OF THE INVENTION
[0014] An object of the invention is to provide an extended release formulation that releases the pharmacologically active component at a constant rate independently of the decreasing area of the formulation over an extended period of time.
[0015] A second object of the invention is to provide an extended release formulation of a pharmacologically active substance having a low aqueous solubility.
[0016] A third object of the invention is to provide an extended release formulation that releases the active component by erosion and/or dissolution.
SUMMARY OF THE INVENTION
[0017] In brief the present invention concerns formulation having extended and essentially constant release rate. The new formulation is distinguished by an accelerating erosion and/or dissolution of the surface of the formulation. The formulation comprises a finely divided drug having low solubility in water dispersed or dissolved in at least one erodable hydrophilic polymeric matrix.
DETAILED DESCRIPTION OF THE INVENTION
[0018] In order to obtain an essentially constant release rate according to the present invention the erosion/release rate must increase with time to compensate for the decreasing release surface area, which mathematically requires a modification where the release rate constants are functions of time.
Q t Q ∞ = 1 - ( 1 - ( k r + r t t ) C 0 r 0 t ) 2 ( 1 - 2 ( k h + h t t ) C 0 h 0 t )
[0019] wherein r t and h t are the rate increase constants for radius and thickness.
[0020] In practice control of the release rate is thus performed by the following factors:
[0021] amount of active drug
[0022] type of matrix former
[0023] viscosity (i.e. degree of polymerisation, molecular weight) of the matrix former
[0024] amount of matrix former
[0025] type and amount of accelerating agent
[0026] type and amount of plasticiser
[0027] granulate size distribution
[0028] tablet geometry
[0029] compaction force
[0030] Drug
[0031] According to the present invention the drug is a pharmacologically active substance of low aqueous solubility which in this context means that the solubility should be less than 100 mg/ml. Particularly interesting drugs for which the invention is applicable are those having a solubility less than 20 mg/ml. Due to the low solubility of the drug the gradient driving diffusion of the drug through the hydrated polymer matrix is too small to allow for more than a minute fraction of the release rate.
[0032] Examples of drugs suitable for the release formulation according to the present invention are dicofenac sodium, glipizide, nifedipine, felodipine, cisapride maleate.
[0033] Matrix
[0034] The hydrophilic polymer matrix glues the particles, drug and excipients, together and acts to retard and control the dissolution of the matrix.
[0035] Examples of hydrophilic polymers forming the matrix are hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, guar gum, polyethylene oxide or a mixture thereof. The higher the proportion matrix former is the slower the release rate becomes and this is also used to control the release rate. Preferably the matrix former is a mixture of 1-10% by weight hydroxypropyl cellulose and 10-50% by weight hydroxyethyl cellulose, preferably 20-30%.
[0036] Osmotic/Accelerating Agent
[0037] This optional excipient is water soluble but otherwise inert material that is added in order to increase the thermodynamic water gradient into the tablet, thereby accelerating the erosion/dissolution rate. Examples of such excipients are pharmaceutically acceptable water soluble substances eg. sugars such as lactose, sacharose, glucose, sugar alcohols such as sorbitol, mannitol, salts, such as sodium chloride. The accelerating agent should have a solubility of 300-1000 g/l, preferably 500-800 g/l and constitute 1-50% by weight, preferably 20-30 % by weight of the formulation.
[0038] Plasticiser
[0039] Depending on the nature of the polymer, a plasticiser may be added in order to facilitate the deformation of granules during compaction. The plasticiser should be a GRAS (=Generally Regarded As Safe) non volatile agent capable of lowering the glass transition temperature of the matrix former. An example of a suitable plasticiser is low molecular weight polyethylene oxide which are in liquid form at room temperature (e.g. PEO 400).
[0040] Binder
[0041] A final optional excipient is a low viscosity polymer-binder. Examples of such binders are hydroxypropyl cellulose and polyvinyl pyrrolidone.
[0042] One optional excipient may be inert filler to adjust the size of the matrix, particularly if the dose of the drug is low.
[0043] Lubricant
[0044] Any conventional lubricant such as magnesium stearate in amounts varying between 1 and 5% by weight may be used.
[0045] Granulation and Compaction
[0046] The components are wet granulated either using the matrix former as binder or by using an additional binder.
[0047] The release rate and the acceleration of the release rate is controlled by the rate of water transport into the matrix. This is apart from the composition also dependent on the porosity and structure of the matrix.
[0048] These factors are controlled by granulate size distribution, granulate plasticity, compaction force and pressure distribution. The latter highly dependent on the axial geometry of the compact.
[0049] To achieve appropriate function and reproducibility a free flowing granulate of narrow particle size distribution is essential. The granulate should be suffciently plastic to deform under pressure and the axial geometry should be flat to achieve an even force distribution in the granulate bed.
[0050] The invention is further illustrated by the following examples:
EXAMPLE 1
[0051] Effect of different amounts matrix polymer
Composition mg/tablet Glipizide 10.0 Hydroxyethyl cellulose (HEC) 25.0 (high viscosity quality Natrosol 250 M) 6.0, 8.7, 12.0, 16.7, 20.0 Hydroxypropyl cellulose 7.8 Lactose 55.2 PEG 400 1.0 Ethanol 55.0 Magnesium stearate 1.0
[0052] Glipizide, HEC and lactose are sieved through a 1 mm sieve and dry mixed in an intensity mixer. HPC and PEG are dissolved in ethanol and stirred overnight to ensure complete swelling. The powder mixture is continuously granulated with the polymer solution in a fluidised bed. The dry granulate is finally mixed with magnesium stearate and the obtained mixture is compressed into a tablet having 6 mm diameter. Release profiles using the USP I method in 0.1M phosphate buffer pH 6.8 are given in FIG. 1 which shows that the release rate can be controlled by the amount HEC.
EXAMPLE 2
[0053] Effect of the matrix polymer viscosity and amount of polymeric matrix
Composition mg/tablet Glipizide 10.0 Hydroxyethyl cellulose (high viscosity 25.0 quality) or Hydroxyethyl cellulose (low viscosity, 50.0 Natrosol 250 HX) Hydroxypropyl cellulose 7.8 Lactose 55.2 PEG 400 1.0 Ethanol 55.0 Magnesium stearate 1.0
[0054] Manufacture and analysis as in example 1. The release profile is given in FIG. 2 shows that the low viscosity polymer requires twice the amount of the high viscosity polymer to obtain the same release rate.
EXAMPLE 3
[0055] Effect of amount of drug
Composition mg/tablet Glipizide 10.0 Hydroxyethyl cellulose 25.0 Hydroxypropyl cellulose 7.8 Lactose 55.2 PEG 400 1.0 Ethanol 55.0 Magnesium stearate 1.0 Glipizide 5.0 Hydroxyethyl cellulose 5.0 Hydroxypropyl cellulose 7.8 Lactose 55.2 PEG 400 1.0 Ethanol 55.0 Magnesium stearate 1.0
[0056] Manufacture and analysis as in example 1. The release profile using the USP I method in 0.1M phosphate buffer pH 6.8 is given in FIG. 3 shows that the release rate is controlled by the matrix and is less affected by the amount of drug.
EXAMPLE 4
[0057] [0057] Composition mg/tablet Nifedipine 30.0 Hydroxyethyl cellulose 25.0 Hydroxypropyl cellulose 7.8 Lactose 35.2 PEG 400 1.0 Ethanol 55.0 Magnesium stearate 1.0
[0058] Manufacture as in Example 1 The release profile is given in FIG. 4.
EXAMPLE 5
[0059] [0059] Composition mg/tablet Cisapride maleate 40.0 Hydroxyethyl cellulose 25.0 Hydroxypropyl cellulose 7.8 Lactose 25.2 PEG 400 1.0 Ethanol 55.0 Magnesium stearate 1.0
[0060] Manufacture as in Example 1. The release profile is given in FIG. 4.
[0061] The different release profiles obtained is probably explained by the different rates of dissolution of the drugs.
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The present invention concerns an extended release formulation having an accelerating erosion and/or dissolution rate of the surface of the formulation. The formulation comprises a drug having low solubility in water dispersed or dissolved in at least one erodable hydrophilic polymeric matrix.
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FIELD OF THE INVENTION
The field of the present invention relates to tests for determination of Chemical Oxygen Demand (COD) in aqueous samples. More particularly, it relates to a method of removal of chloride ion from COD test samples, so that the chloride ion does not cause an erroneous high sample reading.
BACKGROUND OF THE INVENTION
Oxygen demand is an important parameter for determining the effect of organic pollutants on receiving water. As microorganisms in the environment consume these materials, oxygen is depleted from the water. This can have an adverse effect on fish and plant life.
There are three main methods of measuring oxygen demands: directly, by biochemical oxygen demand (BOD) and/or chemical oxygen demand (COD), and indirectly by total organic carbon (TOC) procedures. BOD, because it uses microorganisms for oxidation, gives the closest picture of the biological processes occurring in a stream. However, results are not available for five days, and the BOD test is inadequate as an indicator of organic pollution when used with industrial waste water containing toxic materials which poison the microorganisms and render them unable to oxidize wastes.
Unlike BOD, the two other methods do not use biological processes, and are therefore faster and not affected by toxic materials. A strong oxidizing agent or combustion technique is used under controlled conditions in the TOC method to measure the total amount of organic material in a sample. The results obtained may not be as accurate as the results reached through the COD or BOD method in predicting environmental oxygen demand because oxygen demands may differ between compounds with the same number of organic carbons in their structures. The difference in oxygen demand between two compounds containing the same amount of organic carbon can be seen in the following equations showing the oxidation of oxalic acid and ethanol:
oxalic acid: C 2 H 2 O 4 +1/2 O 2 →2CO 2 +H 2 O
ethanol: C 2 H 5 OH+3O 2 →2CO 2 +3H 2 O
Each molecule of ethanol uses up six times as much oxygen as an equivalent amount of oxalic acid, and thus would have a much greater effect on the dissolved oxygen present in a receiving water. Estimating environmental oxygen demand (as with BOD and COD) requires complete oxidation of carbon and hydrogen present in the organic matter. Thus, while TOC is a more direct expression of total organic content than BOD or COD, it does not provide the same kind of information. An empirical relationship can exist between TOC, BOD and COD, but the specific relationship must be established for a specific set of sample conditions.
Currently, the COD test has a fairly specific and universal meaning: the oxygen equivalent of the amount of organic matter oxidizable by potassium dichromate in a 50% sulfuric acid solution. Generally, a silver compound is added as a catalyst to promote the oxidation of certain classes of organics. Typically, a mercuric compound may be added to reduce interference from the oxidation of chloride ions by the dichromate which will give false high COD readings. The end products of organic oxidations are carbon dioxide and water.
After the oxidation step is completed, the amount of dichromate consumed is determined either titrimetrically or colorimetrically. Either the amount of dichromate reduced (Chromium III) or the amount of unreacted dichromate (Chromium VI) remaining can be measured. If the latter method and colorimetry are chosen, the analyst must know the precise amount of dichromate added and be able to set the instrument wavelength very accurately, since readings are routinely taken on the "shoulder" of the Chromium VI absorbance peak. Wavelength settings must be reproduced precisely in order to avoid errors when using a previously generated calibration curve.
Dichromate was first used in the COD test over 50 years ago. Before that time, potassium permanganate was the oxidant of choice. Analysts have tried many other reagents, such as potassium persulfate, cerium sulfate, potassium iodate and oxygen itself. Generally these other oxidants have not been satisfactory.
A prior case commonly assigned, U.S. Ser. No. 08/475,187, filed Jun. 7, 1995, and entitled "Manganese III Method For Chemical Oxygen Demand Analysis", relates to a new COD test that eliminates the use of dichromate in sulfuric acid and replaces it with another COD test reagent containing Mn +3 ions and of improved performance. The subject matter of that application is incorporated herein by reference.
As mentioned previously, the current state of the art involves the addition of mercuric compounds added to reduce interference from the oxidation of chloride ions by the dichromate. The addition of mercuric salts, while satisfactory to eliminate interference from chloride ion in aqueous COD samples, is itself unsatisfactory because mercury is a pollutant and known toxicant, which makes it undesirable for use in COD analysis. Mercury has its own polluting and environmental risks. There is, therefore, a present and continuing need for the development of a means of removing potentially interfering chloride ions from aqueous COD samples which avoids use of mercury salts, and which does not in any way interfere with the accuracy of the COD analytical procedure. This invention has as its primary objective the fulfillment of this need.
An additional objective is to provide a cartridge device which can be provided in a kit for chemical COD analysis that can be conveniently used by operators to conduct a pretreatment chloride removal step prior to analysis of an aqueous COD sample.
The method and means of accomplishing each of the above objectives will become apparent from the detailed description of the invention which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective and exploded view of the cartridge of the present invention with the inner and outer sections aligned for mating relationship.
FIG. 2 shows the inner and outer sections in mating relationship.
FIG. 3 shows in cross section a complete cartridge unit inserted in a test tube.
FIG. 4 shows a bottom view of the inner cartridge.
FIG. 5 shows a bottom view of the outer cartridge.
SUMMARY OF THE INVENTION
The invention relates to a method of pretreating aqueous COD samples to remove interference from chloride ions. Bromide and iodide ions are also removed, but they are not normally present in aqueous COD samples in concentrations high enough to constitute significant interference. In the method, the aqueous sample is acidified with a mineral acid, preferably sulfuric acid, and then passed through a source of bismuthate or other pentavalent Bismuth-containing ion or compound, preferably in solid form. After this pretreatment the sample is then used for COD analytical testing. In another aspect of a related invention, the process is conducted using inner and outer cartridges adapted to matingly fit within each other to form a cartridge unit. Both cartridges are made of materials that are inert to acidified test samples, any chloride present or chlorine generated, and not retain any organics present in the test sample and have open upper ends and a porous lower end. The outer cartridge contains solid form sodium bismuthate which may be mixed with a filter aid, and the inner cartridge contains a removable filter which may be removed and added to the COD test sample so that solid organics filtered out during the pretreatment process are recombined with the liquid portion of the sample so that the COD test results represent the total of soluble plus insoluble organic compounds and/or mixtures, yielding a test result representative of the total COD of the sample.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the process of this invention, a typical aqueous COD test sample is pretreated to remove interference from chloride ion. The pretreatment involves materials which avoid the conventional prior art treatment with mercury salts as used to complex chloride ion and render it unavailable for reaction in the COD test. In the present process the pretreatment involves reacting an acidified aqueous COD sample with a source of bismuthate ion or other pentavalent bismuth source.
The source of bismuthate or pentavalent bismuth ion is not critical, and it may be bismuth tetroxide, bismuth pentoxide, free bismuthic acid, or, more preferably, a Group I or Group II bismuthate salt. The most preferred are Group. I bismuthate salts, and particularly sodium bismuthate and potassium bismuthate. In the process of the reaction, the Bi +5 is reduced by any chloride ion to Bi +3 and the chloride ion is oxidized to free chlorine. In this way, the chlorine escapes as the free gas.
While the bismuthate ion may be added as an aqueous solution since it has some level of solubility, it is much preferred that it be used in solid form as explained below. Since the bismuthate reaction with chloride ion is believed to be a surface reaction, the reaction is facilitated if the bismuthate, for example, in the form of solid sodium bismuthate, is mixed with a filter aid to increase available surface area of the bismuth compound for reaction with chloride and facilitate flow of the liquid sample through the matrix. Any such filter aid, if used, must be inert to acidified test samples, any chloride present or chlorine generated, and not retain or contribute any organic compounds. Numerous filter aids are available and can be used, but the most preferred are inert high-density glass beads of 40 micron average size. Suitable glass beads are obtained from 3M and sold under the trademark Empore™ 400.
It is preferred that a mixture of the bismuthate ion or pentavalent bismuth source, such as sodium bismuthate, and the inert filter aid be 1:1 on a volume basis. While this is not critical, a 1:1 relationship does seem to perform satisfactorily in that it allows the acidified test sample to freely flow through the solid form bismuthate reagent, while at the same time providing intimate contact. Other ratios have been tested and found to be satisfactory, and may be desirable due to cost or other important factors. It is conceivable that other inert filter aids such as clays like diatomaceous earth, etc., may be employed as well.
The aqueous COD sample is acidified prior to contacting it with the solid form bismuthate or other pentavalent bismuth source. Any non-halogen mineral acid is suitable, such as sulfuric, phosphoric or nitric acids. The acid concentration for sulfuric acid should be within the range of from 3% to 50%, and generally from 8% to 25% is preferred. This corresponds to normalities of from about 1 normal to 18 normal, and preferably from 3 normal to 9 normal. The current procedure operates at about 10% sulfuric acid (approximately 3.5 normal to 4 normal) which is easily obtained by combining 1 part concentrated sulfuric acid, with 9 parts of sample. If the acid is more dilute than about 1 normal, the bismuthate oxidation-reduction reaction will not occur fast enough, and if it is much more concentrated than 18 normal, the bismuthate or pentavalent bismuth will attack organic compounds either directly or through the generation of intermediate oxidizing agents.
Applicant does not wish to be bound by any theory of operation, but notes that it is surprising that chloride is selectively oxidized in the presence of organics which one might also expect to be oxidized but apparently are not. It is believed that the reaction occurs on the surface of the bismuthate compound particles.
The pretreatment step can be conducted in a variety of ways, but the preferred way is in conjunction with the cartridge unit herein described. In this way there is a pretreatment with solid form bismuthate in a manner that does not remove any organics, which of course need to be retained in order to get an accurate COD analysis.
Turning to FIG. 1, it shows the device in perspective and exploded view. The device or composite cartridge unit 10 is comprised of an outer cartridge 12 and an inner cartridge 14. Looking first at outer cartridge 12, it has an open top end 16 and a perforated bottom end 18 joined by circular wall 20 to form a cylindrical shape. Top end 16 has a shoulder portion 22 and rim 24. Positioned over the perforated bottom end 18 is fixed porous filter 26 (see FIG. 2) and held in place in some manner such as a press fit or welded configuration. Positioned on filter 26 is a mixture of solid form bismuthate and filter aid 28. Positioned on or above mixture 28 is a fixed porous filter 30.
The inner cartridge 14 has an open top 32 and a perforated bottom 34, joined by a similar circular wall 36. Positioned on perforated bottom 34 is a removable press fit porous filter 38. The diameter of inner cartridge 14 is such that it can matingly fit inside of the open top 16 of outer cartridge 12 encapsulating the reagent mixture 28 as shown in FIG. 2. Outer cartridge 12 can then be inserted in the top of test tube 40 as illustrated in FIG. 3.
Both outer cartridge 12 and inner cartridge 14 are made of materials that are inert to the acidified sample and reaction products such as chlorine gas. Numerous materials can be employed, but a very suitable inert material is polypropylene. Other polymeric alpha olefins such as polyethylene could also be utilized. The precise material is not critical, as long as it is inert to the acidified sample and reaction products. Filter 38 must additionally be inert to the COD reagent under test conditions (oxidizing acid media at elevated temperature).
In actual operation, the analytical test using the outer and inner cartridges containing the reagent and filters assembled together as a unit 10 is conducted in the following manner. A test sample is mixed with the mineral acid, preferably sulfuric acid, to the concentrations previously specified. The COD test reagent, the prior art dichromate reagent or the Manganese III reagent of the previously incorporated by reference Miller application, is placed in test tube 40. A 0.60 milliliter sample of the aqueous COD material diluted 1:9 with the sulfuric acid solution previously referred to is inserted into the open mouth or top of the previously-described cartridge unit 10. The test tube 40 is then, for example, placed in a centrifuge and centrifuged to draw the acidified aqueous COD sample through press fit filter 38, the perforated bottom 34 of cartridge 14, the fixed filter 30, through the mixture of bismuthate and filter aid 28, through fixed filter 26, perforated bottom 18 of cartridge 12 and down into test reagent 42 in test tube 40. As the acidified aqueous COD sample is pulled through the cartridge unit by centrifugal action, the previously referred to oxidation-reduction reaction occurs. Bismuthate Bi +5 is reduced to Bi +3 ion, and chloride (Cl - ) is oxidized to free chlorine which escapes as a gas. As can be seen, any chloride ion is removed by the process. In order to recover any organics that may have been removed as solid particles by filter 38, it is removed from inner cartridge 14 and added to the reagent 42 in test tube 40. Thereafter the COD analysis occurs in conventional fashion.
The amount of time that the acidified aqueous COD sample is in contact with the reagent in the cartridge must be adequate for the reaction to occur. The amount of time for the centrifugation must be adequate to both allow time for the reaction to occur and for the sample to pass as completely as possible through the cartridge and the reagent it contains. The rate at which the sample flows through the cartridge is also a function of the pore size, thickness and composition of the filters selected for the cartridge unit. Filters composed of glass fiber or polymeric materials have been found to be suitable, provided they are inert to acidified test samples, any chloride present or chlorine generated, and not retain or contribute any organic compounds. A restriction on filter 38 is that it must be inert to the digestion process that occurs in solution 42 in test tube 40. An additional restriction on filters 26 and 30 is that they must be inert to the bismuthate reagent 28.
The rate is also a function of the design of the centrifuge unit, specifically, the radius of the arc traveled by the unit in the test tube and the rate of travel (rpm), which together dictate the g-force on the unit and the sample it contains. When centrifugation is employed, suitable results can be obtained in a fixed time between 1 and 5 minutes, depending on the design of the centrifuge, the rpm setting as previously described and the composition of the filters. An Eppendorf Model 5416 centrifuge gave satisfactory results when samples were spun at 2500 rpm for 3 minutes. Equally satisfactory results were obtained using a 2-step centrifugation process where the first step occurs at a slower speed and duration (500 rpm for 2 minutes) adequate to allow time for the aqueous solution to be in contact with the bismuthate, and a second step which utilizes a higher speed (2500 rpm for 1 minute) to force as much of the aqueous sample out of the cartridge unit and into the test tube as possible. The 2-step centrifugation has different flow requirements than the previously described single-step process, and, hence, uses a different combination of filter materials, typically glass fiber filters only, though some polymer filters may also be acceptable.
Filters 26 and 30 have been described here as separate pieces, but it is possible for both inner cartridge 14 and outer cartridge 12 to have integrally welded filters. With respect to inner cartridge 14, filter 30 would be positioned above perforated bottom end 34 and below press fit filter 38. The preferred method of forcing aqueous COD samples through the cartridge is by centrifugation. Equally satisfactory results were obtained with vacuum filtration. In this method, the sample would be pulled via vacuum through the solid bismuthate. Another alternative is to force the acidified aqueous sample through the cartridge under pressure.
The following examples are offered to further illustrate, but not limit, both the process and the device of the present invention. In the test as outlined below, in order to test efficacy of chloride removal, a blank containing no chloride was used, and thereafter, controls with added amounts of 200 ppm of chloride, 500 ppm of chloride and 1000 ppm of chloride were made. The blank was COD tested using a Bach Company Model DR3000 spectrophotometer and an average value for 9 trials was obtained of 1.470 absorbance. Thereafter, the known test samples containing 200 ppm, 500 ppm and 1000 ppm of chloride were tested. Absorbance readings were thereafter taken. Generally, for the Each system as the absorbance reading goes down, the COD value increases. Thus, the objective is to keep the reading as close as possible to the blank. If this is accomplished, it shows that the chloride is not interfering to give a false high reading.
In accordance with the process, cartridges were prepared as previously described. Outer cartridge 12 contained 0.2 cubic centimeters of sodium bismuthate mixed with filter aid on a 1:1 volume ratio. Concentrated sulfuric acid, 36 normal, and samples were mixed in a 1:9 ratio, and 0.6 ml of this mixture was pipetted into the inner cartridge 14 of the assembled unit. Thereafter, it was placed in a centrifuge and spun for 2 minutes at 500 rpm followed by 1 minute at 2500 rpm. Thereafter, the press fit filter 38 was taken out and added to the reagent 42 in test tube 40 followed by COD testing using the Each Model DR 3000 spectrophotometer.
As indicated for the blank sample with 9 trials, the average absorbance value was 1.470. Table I below shows the values of the blank and of five separate measurements for samples containing 200 ppm, 500 ppm and 1000 ppm chloride and one value for each showing the results of testing in the presence of chloride without benefit of the pretreatment process. As can be seen from the table, deviation from the average value for the blank 1.470 was very small as compared to no pretreatment, indicating that chloride had effectively been removed so that there was minimal chloride interference.
TABLE I______________________________________Absorbance Value Value w/o Value Value Value Value Value Pre-Sample 1 2 3 4 5 Avg. Treatment______________________________________1 Blank (9 trials were averaged for this "blank" 1.470 value)→2 Cl-200 1.463 1.462 1.423 1.427 1.458 1.447 1.3753 Cl-500 1.443 1.453 1.481 1.459 1.438 1.455 1.2504 Cl-1000 1.435 1.426 1.425 1.423 1.437 1.429 1.075______________________________________
It therefore can be seen that the invention accomplishes at least all of its stated objectives.
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A method of pretreating aqueous chemical oxygen demand (COD) samples to remove the risk of potential chloride ion interference. The method comprises acidifying an aqueous COD test sample, and thereafter passing the acidified sample through a source of pentavalent bismuth (Bi 5+ ) such as sodium bismuthate.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for the production of an aqueous dispersion of a N-substituted N',N'-alkylene urea. More particularly, this invention relates to a novel method for the production of an aqueous dispersion of a N-substituted N',N'-alkylene urea by the reaction of an alkylene imine with an isocyanate.
2. Description of Prior Art
Such N-substituted N',N'-alkylene ureas as diphenylmethane-bis-4,4'-N,N'-dialkylene ureas (hereinafter referred to as "DPU") and N-alkyl-N',N'-alkylene ureas are compounds known to the art and are utilized extensively as cross-linking agent for resin, textile processing agents such as softening agent, waterproofing agent and wrinkleproofing agent, paint and ink, and resin modifiers. Further, because they have high cross-linking rates and are capable of treatments at low temperatures, they prove to be important industrial materials [Textile Res. J. 31, 57 (1961)].
Heretofore, water insoluble N-substituted N',N'-alkylene urea powders have been handled, in most cases, as dissolved in organic solvents such as dimethylformamide (DMF), dioxane, acetone and alcohols. These N-substituted N',N'-alkylene ureas, when handled in the form of dust and suffered to be inhaled, can cause harm to the human body and, when handled in the form of a solution in an organic solvent without due care, can induce fire hazard. In the circumstance, the desirability of handling these compounds in a safer and more convenient form of aqueous dispersion instead of powder or solution has found growing recognition.
A method for producing an alkylene urea by causing an alkylene isocyanate having at least 10 carbon atoms to react with ethylene imine in water preferably in the presence of a dispersant or an emulsifier has been known to the art (British Pat. No. 799,045). By such methods, stable aqueous dispersion cannot be obtained, unless the other component is added into the resulted aqueous dispersion.
An object of this invention, therefore, is to provide a novel method for the production of an aqueous dispersion of a N',N'-alkylene urea.
Another object of this invention is to provide a novel method for the production of a stable aqueous dispersion of a N-substituted N',N'-alkylene urea by the reaction of an alkylene imine with an isocyanate in water in the presence of a specified surface active agent.
SUMMARY OF THE INVENTION
The objects described above are accomplished by a method for the production of an aqueous dispersion of a water insoluble N-substituted N',N'-alkylene urea having the general formula I: ##STR5## wherein R 1 denotes alkyl having 6 to 20 carbon atoms, phenyl or ##STR6## in case of m=1, or R 1 denotes alkylene having 6 to 20 carbon atoms, phenylene or ##STR7## in case of m=2, where X denotes H, CH 3 or OCH 3 and n is 0 or 1, R 2 denotes H or CH 3 , R 3 denotes H, CH 3 or C 2 H 5 and R 4 denotes H or CH 3 , by the reaction of an alkylene imine having 2 to 4 carbon atoms with an isocyanate represented by the formula II:
R--NCO (II)
wherein R denotes an alkyl having 6 to 20 carbon atoms, ##STR8## wherein X and n are the same as above in the presence of at least one surface active agent selected from the group consisting of anionic surface active agents and nonionic surface active agents under vigorous stirring.
BRIEF DESCRIPTION OF THE DRAWING
FIGURE is an example of a device for conducting a process for this invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
In accordance with the present invention, a stable aqueous dispersion of a N-substituted N',N'-alkylene urea represented by the general formula I is obtained by adding an isocyarate represented by the general formula II into an aqueous solution of an alkylene imine having 2 to 4 carbon atoms in the presence of at least one surface active agent selected from the group consisting of anionic surface active agents and nonionic surface active agents and dispersing the powdered N-substituted N',N'-alkylene urea.
Alkylene imines having 2 to 4 carbon atoms are represented by the following general formula III: ##STR9## wherein R 2 , R 3 and R 4 is the same as above. Typical alkylene imines are ethylene imine, propylene imine, 1,2-butylene imine, 2,3-butylene imine and isobutylene imine. Among other alkylene imines, ehtylene imine proves particularly desirable.
Concrete examples of the isocyanate represented by the general formula II are alkyl monoisocyanates having 6 to 20 carbon atoms, preferably 16 to 20 carbon atoms, in their alkyl groups, such as hexyl isocyanate, heptyl isocyanate, octyl isocyanate, decyl isocyanate, dodecyl isocyanate, undecyl isocyanate, hexadecyl isocyanate, heptadecyl isocyanate, octadecyl isocyanate, nonadecyl isocyanate, and eicocyl isocyanate, and aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 3,3'-bitolylene-4,4'-diisocyanate, dianisidine diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), and 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate. Among other isocyanates, MDI proves particularly desirable.
Examples of the anionic surface active agents which are advantageously used in this invention include those of straight-chain alkylbenzene sodium sulfonate type ##STR10## alcohol-sulfate type R--OSO 3 Na, polyoxy-ethylenealkyl ether sulfate type R--O (CH 2 CH 2 O) n SO 3 Na, polyoxy-ethylene-alkylphenyl ether sulfate type ##STR11## α-olefin sulfonate type RCH═CH(CH 2 ) n SO 3 Na, dialkyl sulfosuccinate type ##STR12## polyoxyethylene carboxylic ester sulfate type R--COO (CH 2 CH 2 O) n SO 3 Na, polyoxyethylene carboxylic ester phosphate type ##STR13## and β-naphthalene sulfonic acid-formaldehyde polycondensate type ##STR14##
Examples of the nonionic surface active agents which are advantageously used herein include those of polyoxy-ethylene alkyl ether type R--O (CH 2 CH 2 O) n H, polyoxyethtlene alkylaryl ether type ##STR15## polyoxyethylene alkyl amine type ##STR16## polyoxyethylene alkyl amide type ##STR17## polyoxyethylene sorbitan fatty ester type ##STR18## (wherein, R' represents an alkyl having 6 to 25 carbon atoms and m an integer having the value of 5 to 50), Pluronic type HO--CH 2 CH 2 O) a (CH 3 CHCH 2 O) b (CH 2 CH 2 O) c H (wherein, a, b and c each have a value greater that 1 and the sum of a, b and c has a value of 20 to 300), the Tetronic type ##STR19## wherein, X through X"' each have a value greater than 1, y through y"' each have a value greater than 1 and the sum of X, X', X", X"', Y, Y', Y"' and Y"' has a value of 20 to 600.
These anionic and nonionic surface active agents can be used either singly or in the form of a varying combination of anion-anion, nonion-nonion, or anion-nonion agents. Although the selection of an anionic and/or nonionic surface active agent is not particularly liminted, it is desired to be such that the HLB value of the selected surface active agent has a value of not less than 9. Particularly when an alkylene monoisocyanate is adopted, the value of HLB is desired to fall in the range of 9 to 20, preferably 10 to 16. When an aromatic diisocyanate is adopted, the value of HLB is desired to be not less than 15, preferably to be in the range of 16 to 20.
The amount of the anionic and/or nonionic surface active agent to be incorporated is in the range of 0.1 to 20% by weight, preferably 1 to 10% by weight, based on the amount of N-substituted N',N'-alkylene urea to be produced. Particularly when a nonionic surface active agent is used in the reaction using an aromatic diisocyanate, the amount of the surface active agent is in the range of 1 to 10% by weight. The aqueous dispersion of a N-substituted N',N'-alkylene urea which is obtained by the present invention is amply stable. When an anionic and/or nonionic surface active agent is further added at a proper time to the aqueous dispersion obtained as described, there can be obtained a stable aqueous dispersion.
This invention does not specifically define the reaction time between the alkylene imine and the isocyanate. The reaction temperature is required not to exceed 25° C. and desired to fall in the range of 5° to 15° C. If the reaction temperature exceeds 25° C., the reaction of isocyanate with water gives birth to a large amount of urea compounds and the reaction of alkylene imine with isocyanate is consequently impeded. Dispersion of the N-substituted N',N'-alkylene urea formed during the reaction should be conducted simultaneously with the reaction. If necessary, the isocyanate may be pulverized by a sand mill, a ball mill or the like during the reaction. During the reaction of alkylene imine with isocyanate, the mixture of the reactants should be stirred vigorously. Further, the reaction product may be stirred vigrously after completion of the reaction. This stirring is desired to be carried out with a powerful mixer such as a homo-mixer, a line mixer or a line mill. In these mixer, the liquid to be treated is inhaled from an inhalation port by utilizing pressure difference between the inhalation port and an exhalation port occured by high speed rotation of turbine and is pulverized, mixed, stirred, emulsified and dispersed by the action of shearing force, pulverization, impact, turbulence, etc. occured at fine and uniform gap between the turbine and a radial obstruction portion of a stater.
The amount of the alkylene imine relative to that of the isocyanate is in the range of 1.0 to 1.05 equivalents, preferably 1.01 to 1.03 equivalents per equivalent of the isocyanate group of the isocyanate compounds. The alkylene imine is used in an amount of 1 to 30% by weight, preferably 2 to 20% by weight, based on the amount of water as medium. In the aqueous dispersion consequently obtained, the concentration of the N-substituted N',N'-alkylene urea is in the range of 5 to 50% by weight, preferably 10 to 40% by weight.
In accordance with the present invention, there can be very easily obtained an aqueous dispersion of a N-substituted N',N'-alkylene urea having no residue of highly toxic, alkylene imine. This aqueous dispersion is safe and easy to handle because it irritates the skin and the mucous membrane only sparingly. The aqueous dispersion enjoys lasting stability and retains water-dispersibility for a very long time.
The aqueous dispersion of a N-substituted N',N'alkylene urea suits utility as textile processing agents such as sfotening agent, waterproofing agent and wrinkleproofing agent, peeling agent, mold release agent, cross-linker for resin, adhesive agent, paint, ink and resin modifier.
Now, the present invention will be described more specifically below with reference to working examples. It should be noted that this invention is not limited to these working examples.
In the examples, the produced aqueous dispersions of N-substituted N',N'-alkylene ureas were tested for stability by the following methods, Method 1 and Method 2. Method 1 for testing aqueous dispersion for stability:
A 10-g sample of a given dispersion is placed in a test tube and treated on a centrifugal separator (produced by Hitachi, Ltd. and marketed under designation of 05PR-2 type) at 4000 r.p.m. for 15 minutes. Then, a 5-g portion of the separated liquid is gently removed from the liquid surface and analyzed for N-substituted N',N'-alkylene urea concentration.
Stability (%)=[(N-substituted N',N'-alkylene urea concentration before centrifugal separation)/(N-substituted N',N'-alkylene urea concentration after centrifugal separation)]×100
By this method, the degree of stability of the aqueous dispersion increases with the increasing value (%) so reported. Method 2 for testing aqueous dispersion for stability:
A 100 g sample of a given aqueous dispersion is placed in a 100-ml measuring cylinder, left standing at rest therein at room temperature for one month, and visually examined with respect to condition of dispersion.
EXAMPLE 1
In a 500-ml tall beaker provided with a thermometer, 252.9 g of water, 0.3 g of sodium hydroxide and 3.2 g (5% by weight based on N-octadecyl-N',N'-ethylene urea) of polyoxyethylene alkyl ether (produced by Kao Atlas Co. and marketed under trademark designation of Emulgen 106, HLB=10.5) were thoroughly mixed. The resultant mixture and 8.0 g (0.186 mol) of ethylene imine added thereto were stirred in a homo-mixer at 10° C. to form a uniform solution.
Then, 56.1 g (0.190 mol) of molten octadecyl isocyanate was added dropwise into the solution through a dropping funnel. The reactants were left reacting at the same temperature for 8 hours to afford a stable aqueous dispersion having a N-octadecyl-N',N'-ethylene urea concentration of 18.4% by weight at room temperature. This aqueous dispersion was found by analysis to contain no unaltered ethylene imine.
By Method 1 the stability was found to be 75%. By Method 2, the aqueous dispersion was found to be a stably dispersed condition (substantially) free from supernatant and precipitate.
EXAMPLE 2
In the same apparatus as used in Example 1, 251.0 g of water, 0.3 g of sodium hydroxide, 5.1 g (1.2% by weight based on N-octadecyl-N',N'-ethylene urea) of polyoxyethylene alkylfulfate (produced by kao Atlas Co. and marketed under trademark designation of Emal 200, aqueous 25% by weight solution) and 8.0 g of ethylene imine were stirred in a homo-mixer at 10° C. to produce a uniform solution.
Then, 56.1 g of molten octadecyl isocyanate was added dropwise into the solution and the reactants were left reacting at the same temperature for 13 hours to produce an aqueous dispersion having a N-octadecyl-N',N'-ethylene urea concentration of 18.0% by weight at room temperature. This aqueous dispersion was found by test to contain no unaltered ethylene imine. By Method 1, the stability was found to be 80%. By Method 2, the aqueous dispersion was found to be as stable as that of Example 1.
EXAMPLE 3
In the same apparatus as used in Example 1, 249.7 g of water, 0.3 g of sodium hydroxide, 5.1 g of polyoxyethylene alkyl ether, a nonionic surface active agent, (produced by Kao-Atlas Co. and marketed under trademark designation of Emulgen 106, HLB=10.5), 1.3 g of alkyl sulfate, an anionic surface active agent (produced by Kao-Atlas Co. and marketed under trademark designation of Emal 0), and 8.0 g of ethylene imine were stirred in a homo-mixer at 10° C. to produce a uniform solution.
Then, 56.1 g of molten octadecyl isocyanate was added dropwise to the solution and the reactants were left reacting at room temperature for 24 hours to produce an aqueous dispersion. This aqueous solution was found to have a N-octadecyl-N',N'-ethylene urea concentration of 18.5% by weight. It was found by test to contain no unaltered ethylene imine.
By Method 1, the stability was found to be 82%. By Method 2, the aqueous dispersion was found to be as stable as that of Example 1.
EXAMPLE 4
In a 500-ml tall beaker provided with a thermometer, 229.6 g of water, 0.3 g of sodium hydroxide and 2.9 g (5% by weight based on N-hyxadecyl-N'N'-ethylene urea) of polyoxyethylene alkyl ether (produced by Kao-Atlas Co. and marketed under trademark designation of Emulgen 120, HLB=15.3) were thoroughly dissolved. The resultant solution and 8.0 g of ethylene imine added thereto were stirred in a homo-mixer at 10° C. to produce a uniform solution.
Then, 50.2 g of molten hexadecyl isocyanate was added dropwise into the solution through a dropping funnel and the reactants were left reacting at the same temperature for 8 hours to afford an aqueous dispersion having a N-hexadecyl-N',N'-ethylene urea concentration of 18.0% by weight at room temperature. This aqueous dispersion was found by test to contain no unaltered ethylene imine. By Method 1, the stability was found to be 70%. By Method 2, the aqueous dispersion was found to be as stable as that of Example 1.
Control 1
In the same apparatus as used in Example 1, 252.9 g of water, 0.3 g of sodium hydroxide and 8.0 g of ethylene imine were stirred in a homo-mixer at 10° C. to afford a uniform solution.
Then, 56.1 g of molten octadecyl isocyanate was added dropwise into the solution through a dropping funnel. The reactants were left reacting at the same temperature. During the course of this reaction, the reaction mixture gelled and the reaction could not be continued any further. Thus, no aqueous dispersion of N-octadecyl-N',N'-ethylene urea was obtained.
EXAMPLE 5
In a 500-ml tall beaker provided with a thermometer, 243.1 g of water, 0.3 g of sodium hydroxide and 4.1 g (5% by weight based on diphenylmethane-bis-4,4'-N'N'-diethylene urea) of polyoxyethylene nonylphenol ether (produced by Kao-Atlas Co. and marketed under trademark designation of Emulgen 985, HLB=18.9) were thoroughly dissolved. The resultant solution and 20.7 g of ethylene imine added thereto were stirred in homo-mixer at 10° C. to afford a uniform solution.
Then, 61.8 g of molten MDI was added dropwise into the solution through a dropping funnel and the reactants were left reacting at a temperature of 10° C. for 8 hours to produce a stable aqueous dispersion having a diphyenylmethane-bis-4,4'-N,N'-diethylene urea concentration of 23.8% by weight. This aqueous dispersion was found by test to contain no unaltered ethylene imine.
By Method 1, the stability was found to be 78%. By Method 2, the aqueous dispersion was found to be in a stable dispersed condition (substantially) free from supernatant and precipitate.
EXAMPLE 6
In the same apparatus as used in Example 5, 242.4 g of water, 0.3 g of sodium hydroxide, 4.8 g (1.5% by weight based on diphenyl methane-bis-4,4'-N,N'-diethylene urea) of sepcial carboxylic acid type high-molecular active agent (an aqueous 25% by weight anionic surface active agent solution produced by Kao-Atlas Co. and marketed under trademark designation of Demol EP) and 20.7 g of ethylene imine were stirred in a homo-mixer at 10° C. to produce a uniform solution.
Then, 61.8 g of molten MDI was added dropwise to the solution and the reactants were left reacting at the same temperature for 12 hours, to produce an aqueous dispersion having a diphenyl-methane-bis-4,4'-N,N'-diethylene urea concentration of 23.5% by weight. This aqueous dispersion was found by test to contain no unaltered ethylene imine.
By Method 1, the stability was found to be 80%. By method 2, this aqueous dispersion was found to be as stable as that of Example 1.
EXAMPLE 7
In the same apparatus as used in Example 5, 235.0 g of water, 0.3 g of sodium hydroxide, 7.4 g of polyoxyethylene nonylphenol ether, a nonionic surface active agent (produced by Kao-Atlas Co. and marketed under trademark designation of Emulgen 935, HLB=17.5), 0.8 g of naphthalene sulfonic acid formaline condensate (produced by Kao-Atlas Co. and marketed under trademark designation of Demol N) and 20.7 g of ethylene imine were stirred in a homo-mixer at 10° C. to produce a homogeneous solution.
Then, 61.8 g of molten MDI was added dropwise to the solution and the reactants were left reacting for 19 hours to produce an aqueous dispersion at room temperature. It was found to have a diphenyl-methane-bis-4,4'-N,N'-diethylene urea concentration of 23.2% by weight. This aqueous dispersion was found by test to contain no unaltered ethylene imine.
By Method 1, the stability was found to be 85%. By method 2, the aqueous dispersion was as stable as that of Example 1.
Control 2
In the same apparatus as used in Example 5, 243.1 g of water, 0.3 g of sodium hydroxide and 20.7 g of ethylene imine were stirred in a homo-mixer at 10° C. to produce a uniform solution.
Then, 61.8 g of molten MDI was added dropwise into the solution through a dropping funnel. The reactants were left reacting at the same temeperature. During the course of the reaction, the reaction mixture gelled and the reaction could not be continued any further. Thus, no aqueous dispersion of diphenyl-methane-bis-4,4'-N,N'-diethylene urea could be obtained.
EXAMPLE 8
In a 100 liter of a stirring vessel 1 as shown in a drawing provided with a thermometer (not shown), a stirrer 10, an isocyanate dropping vessel 8, a feeding pipe 3, a vent pipe 11, a discharging pipe 9 and a jacket 2, 63.2 kg of water, 75 g of sodium hydroxide and 0.8 kg (5% by weight based on N-octadecyl-N',N'-ethylene urea) of polyoxyethylene alkyl ether (produced by Kao-Atlas Co. and marketed under trademark designation of Emulgen 106, HLB=10.5) were charged by the feeding pipe 3 and thoroughly solubilized. 2.0 kg of ethylene imine was added into the resultant mixture and was stirred at 10° C. to form a uniform solution.
Then, the solution was recycled to an outer recycling pipe 4 provided with a pump 5, a line mill (manufactured by Tokushu Kika Co.) 6 and a heat exchanger 7 by the pump 5, and at the same time 14.0 kg of molten octadecyl isocyanate was added dropwise into the solution through the dropping vessel 8. The temperature of the reactants in the stirring vessel were maintained at 10° to 15° C. by charging a 50% by weight of aqueous ethylene glycol solution cooling medium from the pipe 12 to the jacket 2 of the stirring vessel 1 and then discharged from the pipe 13, and octadecyl isocyanate and N-octadecyl-N',N'-ethylene urea formed during the reaction in the reactants were pulverized and mixed thoroughly and reacted for 8 hours to afford a stable aqueous dispersion having a N-octadecyl-N',N'-ethylene urea concentration of 18.4% by weight at room temperature. This aqueous dispersion was found by analysis to contain no unaltered ethylene imine.
By Method 1 the stability was found to be 81%. By Method 2, the aqueous dispersion was found to be a stably dispersed condition (substantially) free from supernatant and precipitate.
EXAMPLE 9
In a stirring vessel similar to one as Example 8, 60.8 kg of water, 94 g of sodium hydroxide and 1.2 kg (5% by weight based on diphenyl methane-4,4'-N,N'-diethylene urea) of polyoxyethylene alkyl ether (produced by Kao-Atlas Co. and marketed under trademark disignation of Emulgen 985, HLB=18.9) were charged by the feeding pipe 3 and throughly solubilized. 6.0 kg of ethylene imine was added into the resultant mixture and was stirred at 10° C. to form a uniform solution.
The solution was recycled to an outer recycling pipe 4 provided with a pump 5, a homo-mixer (TK Pipe Line HOMOMIXER 2S5 Type, manufactured by Tokushu Kika Co.) 6 and a heat excharger 7 by the pump 5, and at the same time 17.8 kg of molten MDI was added dropwise into the solution through the dropping vessel 8. The temperature of the reactants in the stirring vessel were maintained at 10° to 15° C. by charging a 50% by weight of aqueous ethylene glycol solution cooling medium to the jacket 2, and MDI and diphenyl methane-4,4'-N,N'-diethylene urea formed during the reaction in the reactants were pulverized and mixed thoroughly and reacted for 9 hours to afford a stable aqueous dispersion of diphenyl methane-4,4'-N,N'-diethylene urea of 25.7% by weight at room temperature. This aqueous dispersion was found by analysis to certain no unaltered ethylene imine.
By method 1 the stability was found to be 81%. By Method 2, the aqueous dispersion was found to be a stably dispersed condition (substantially) free from supernatant and precipitate.
EXAMPLE 10
Example 8 was repeated, except that a sand mill (ATTRITOR, manufactured by Mitsui Miike Seisakusho Co.) was used instead of the line mill to obtain an aqueous dispersion of N-octadecyl-N',N'-ethylene urea. This aqueous dispersion was found by analysis to contain no unattered ethylene imine. By Method 1 the stability was found to be 82%. By Method 2, the aqueous dispersion was found to be a stably dispersed condition (substantially) free from supernatant and precipitate.
EXAMPLE 11
Example 9 was repeated, except that a sand mill (ATRRITOR, manufactured by Mitsui Miike Seisakusho Co.) was used instead of the homo mixer to obtain an aqueous dispersion of diphenyl methane-4,4'-N,N'-diethylene urea. This aqueous dispersion was found by analysis to contain no unaltered ethylene imine. By method 1 the stability was found to be 82%. By Method 2, the aqueous dispersion was found to be a stably dispersed condition (substantially) free from supernatant and precipitate.
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A method for the production of an aqueous dispersion of a water insoluble N-substituted N',N'-alkylene urea having the general formula I: ##STR1## wherein R 1 denotes alkyl having 6 to 20 carbon atoms, phenyl or ##STR2## in case of m=1, or R 1 denotes alkylene having 6 to 20 carbon atoms, phenylene or ##STR3## in case of m=2, where X denotes H, CH 3 or OCH 3 and n is 0 or 1, R 2 denotes H or CH 3 , R 3 denotes H, CH 3 or C 2 H 5 and R 4 denotes H or CH 3 , by the reaction of an alkylene imine having 2 to 4 carbon atoms with an isocyanate represented by the general formula II:
R-NCO (II)
wherein R denotes an alkyl having 6 to 20 carbon atoms, ##STR4## wherein X and n are the same as above in the presence of at least one surface active agent selected from the group consisting of anionic surface active agents and nonionic surface active agents under vigorous stirring.
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BACKGROUND OF THE INVENTION
The present invention relates to a tracking servo circuit, and more particularly, to a tracking servo circuit for controlling the movement of a pickup device relative to a disk type recording medium.
A compact disc (CD) is mainly used as a digital audio recording medium, but it can also be used as a read only memory (CD-ROM) for storing various types of digital data read by computers.
FIG. 1 is a schematic block diagram showing a conventional disk reproduction apparatus. A disc 1 has a spiral recording track formed on at least one of its surfaces. Digital data, which is in a predetermined format, is recorded along the recording track. The disc reproduction apparatus includes a pickup 3 to read the data recorded on the recording track. The disc reproduction apparatus further includes a servo mechanism for controlling the position of the pickup 3 relative to the disc 1 so that the pickup 3 traces the recording track properly.
As shown in FIG. 2, digital data is recorded as a plurality of pits (bumps) that are formed on the recording track of the disc 1 . The digital data undergoes EFM modulation to generate an EFM signal. The pits are formed having a predetermined dimension in correspondence with the EFM signal. The disc 1 is rotated by a spindle motor 2 . The spindle motor 2 rotates the disc 1 at a predetermined speed in accordance with a drive signal SD generated by a servo controller 6 .
The pickup 3 is arranged opposite the recording track of the disc 1 . An actuator 4 , which is operated in accordance with a drive signal TD, moves the pickup 3 in the radial direction of the disc 1 . The pickup 3 includes laser beam sources and sensors. As shown in FIG. 2, the pickup 3 generates a main reading beam P and a pair of auxiliary reading beams T 1 , T 2 which are radiated toward the recording track. The main reading beam P is used to detect pits on the recording track surface. The auxiliary reading beams T 1 , T 2 are used to detect when the pickup 3 moves away from the recording track. The reading beams P, T 1 , T 2 radiated against the pits of the disc 1 are reflected toward the sensor as weak lights. The reading beams P, T 1 , T 2 radiated against portions other than the pits of the disc 1 are reflected toward the sensor as strong lights. When the sensor associated with each of the reading beams P, T 1 , T 2 receives the corresponding reflection beam, the sensor generates a voltage having a value which corresponds to the intensity of the reflected light.
A voltage signal having a value corresponding to the main reading beam P is sent to a signal processor 5 from the pickup 3 . The signal processor 5 conducts a waveform shaping process and a binarizing process on the voltage signal to generate an EFM signal. The EFM signal repetitively goes back and forth between a low level and a high level in accordance with the existence of pits.
The signal processor 5 generates a tracking error signal TE from the difference between the voltage values of the auxiliary reading beams T 1 , T 2 and an off track signal OT from a low frequency component of the EFM signal. The voltage value corresponding to the auxiliary reading beam T 1 is substantially the same as the voltage value corresponding to the auxiliary reading beam T 2 when the pickup 3 is accurately tracking the recording track (i.e., when the pickup 3 is at the proper position). Under these conditions, the tracking error signal TE is maintained at a null level. When the pickup 3 is not accurately tracking the recording track (i.e., when the pickup 3 is not at the proper position), for example, when the position of the pickup 3 is offset inward from the recording track, the voltage value corresponding to the auxiliary reading beam T 1 becomes smaller than the voltage value corresponding to the auxiliary reading beam T 2 and causes the tracking error signal TE to take a negative value. On the other hand, if the position of the pickup 3 is offset outward from the recording track, the voltage value corresponding to the auxiliary reading beam T 2 becomes smaller than the voltage value corresponding to the auxiliary reading beam T 1 and causes the tracking error signal TE to take a positive value. When the pickup 3 is properly tracking the recording track of the disc 1 , the signal processor 5 continuously outputs the EFM signal. Thus, the EFM signal does not include a low frequency component. Accordingly, the off track signal OT is maintained at a low level when the pickup 3 is properly tracking the recording track.
As shown in FIG. 1, the signal processor 5 sends the tracking error signal TE and the off track signal OT together with the EFM signal to the servo controller 6 . The servo controller 6 generates the spindle motor drive signal SD and the actuator drive signal TD based on the tracking error signal TE and the off track signal OT. The spindle motor drive signal SD controls the spindle motor 2 so that the frequency of the EFM signal is maintained at a predetermined value. The actuator drive signal TD controls the actuator 4 so that the tracking error signal TE has a null level and the off track signal OT is maintained at a low level. The spindle motor drive signal SD and the actuator drive signal TD servo control the spindle and tracking.
FIG. 3 is a chart showing the waveforms of the signals detected when the pickup 3 moves across the lines of the recording track on the disc 1 (when a so-called track jump is performed). The horizontal axis represents time. FIG. 3 shows a state in which the pickup 3 gradually decelerates.
As shown in FIG. 3, the code (polarity) of the pickup 3 is inverted each time the pickup 3 moves across the recording track. Thus, the waveform of the tracking error signal TE is a sine wave during the track jump. A track jump signal TJ is generated by digitizing the tracking error signal TE using a null level of the tracking error signal TE as a threshold value. The track jump signal TJ falls or rises when the center of the pickup 3 is located at the center of the recording track. Furthermore, the EFM signal has a predetermined amplitude when the pickup 3 is located above the recording track. If the pickup 3 moves away from the recording track, the EFM signal maintains a. constant value. Accordingly, the off track signal OT rises or falls when the center of the pickup 3 reaches an end of a pit. Normally, the phase difference between the off track signal OT and the tracking error signal TE is ±90°. Accordingly, the number of times the pickup 3 crosses the recording track is detected by counting the tracking error signals TE or the off track signals OT. The moving direction of the pickup 3 is detected from the difference between the phase of the tracking error signal TE and the phase of the off track signal OT. The movement of the pickup 3 is controlled based on the two detection results.
When moving the pickup 3 in the radial direction of the disc 1 , the pickup 3 is accelerated when the movement starts. When stopping the pickup 3 at a target position, the pickup 3 is decelerated just before reaching the target position. The acceleration and deceleration of the pickup 3 are controlled by the drive signal TD. Normally, to control the stopping of the pickup 3 , a tracking error signal TE having a positive polarity or a negative polarity is acquired. An electromotive force acting in a direction opposite the moving direction of the pickup 3 is applied to the pickup 3 in accordance with the value of the acquired tracking error signal TE. For example, if the pickup 3 moves in an outward direction of the disc 1 and the track jump signal TJ is high, a tracking error signal TE having a positive polarity is acquired and a counter electromotive force, or braking force, is applied to the pickup 3 . When the pickup 3 moves toward the center of the disc 1 and the track jump signal TJ is low, a tracking error signal TE having a negative polarity is acquired.
When a difference occurs between the phase of the track jump signal TJ and the phase of the tracking error signal TE, the tracking error signal TE s acquired from the track jump signal TJ may not have a constant polarity (positive or negative). In this case, deceleration of the pickup 3 may be insufficient. For example, if the track jump signal TJ is delayed from the tracking error signal TE as shown in FIG. 4, the tracking error signal TE s acquired in response to the track jump signal TJ includes a negative polarity period. This accelerates the pickup 3 during the negative polarity period of the tracking error signal TE s . As a result, the pickup 3 may not be able to stop at the target position, causing sliding to occur.
In addition, when the actuator 4 is manufactured, structural and dimensional differences may cause the actuator 4 to have an operational characteristic which differs from other actuators. Thus, if the drive signal TD is processed in the same manner as other actuators, the same operation may not be obtained.
SUMMARY OF THE INVENTION
Accordingly, it is an objective of the present invention to provide a tracking servo circuit that always accurately stops the pickup at a target position.
To achieve the above objective, the present invention provides a tracking servo circuit for stopping a pickup at a target position on a recording track formed on a recording medium. The tracking servo circuit includes a selection signal generator for generating a selection signal in accordance with the polarity of a tracking error signal. The tracking error signal has a positive value when the pickup is located at a first side of the recording track and a negative value when located at a second, opposite side of the recording track. A selector is connected to the selection signal generator. The selector selects one of two data in accordance with the selection signal and outputs the selected data. A drive signal generator is connected to the selector to generate a drive signal for stopping the radial movement of the pickup using the selected data.
A further aspect of the present invention provides a tracking servo circuit for stopping a pickup at a target position on a recording track formed on a recording medium. The tracking servo circuit includes an A/D converter for generating digitized error data from a tracking error signal. The tracking error signal takes a positive value when the pickup is located at a first side of the recording track and takes a negative value when located at a second, opposite side of the recording track. The error data includes a code bit indicating the polarity of the tracking signal. A selection signal generator generates a selection signal in accordance with the code bit. A selector is connected to the A/D converter and the selection signal generator to select one of the error data and a predetermined fixed data in accordance with the selection signal. A drive signal generator is connected to the selector to generate a drive signal for stopping the radial movement of the pickup using the data selected by the selector.
Another aspect of the present invention provides a tracking servo circuit for stopping a pickup at a target position on a recording track formed on a recording medium. The tracking servo circuit includes an A/D converter for generating digitized error data from a tracking error signal. The tracking error signal takes a positive value when the pickup is located at a first side of the recording track and takes a negative value when located at a second, opposite side of the recording track. The error data includes a code bit indicating the polarity of the tracking signal. A first multiplying device is connected to the A/D converter to receive the error data from the A/D converter, multiply the error data with a predetermined first coefficient, and generate a first product. A second multiplying device is connected to the A/D converter to receive the error data from the A/D converter, multiply the error data with a predetermined second coefficient, and generate a second product. A selection signal generator generates a selection signal in accordance with the code bit. A selector is connected to the first and second multiplying devices and the selection signal generator to select one of the first product and the second product in accordance with the selection signal. A drive signal generator is connected to the selector to generate a drive signal for stopping the radial movement of the pickup using the data selected by the selector.
Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:
FIG. 1 is a block diagram showing the structure of a prior art disc reproduction apparatus;
FIG. 2 is a plan view showing the structure of a recording track of a compact disc;
FIG. 3 is a chart showing the relationship between a tracking error signal and an off track signal;
FIG. 4 is a chart showing the relationship between the movement of a pickup and the tracking error signal;
FIG. 5 is a block diagram showing a tracking servo controller according to a first embodiment of the present invention;
FIG. 6 is a chart showing the waveforms of each signal in the tracking servo circuit of FIG. 5;
FIG. 7 is a chart showing the relationship between the movement of a pickup and a tracking error signal;
FIG. 8 is a block diagram showing a tracking servo circuit according to a second embodiment of the present invention;
FIG. 9 is a chart showing the waveforms of each signal in the tracking servo circuit of FIG. 8;
FIG. 10 is a block diagram showing a tracking servo circuit according to a third embodiment of the present invention;
FIG. 11 is a chart showing the waveforms of each signal in the tracking servo circuit of FIG. 10; and
FIG. 12 is a chart showing the relationship between the movement of a pickup and a tracking error signal.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A tracking servo circuit 10 according to a first embodiment of the present invention will now be described with reference to FIGS. 5 to 7 . The tracking servo circuit 10 is employed in lieu of the servo controller 6 of the conventional disc reproduction apparatus shown in FIG. 1 . The tracking servo circuit 10 includes an A/D converter 11 , a register 12 , a selector 13 , a movement direction determiner 14 functioning as a direction detector, an XOR gate 15 functioning as a selection signal generator, and a drive signal generator 16 . The tracking servo circuit 10 operates in accordance with a tracking error signal TE and an off track signal OT provided by signal processors, each of which perform predetermined processes on the output of the pickup.
The A/D converter 11 generates digitized error data ER from an analog tracking error signal TE. Sampling of the tracking error signal TE is carried out by the A/D converter 11 in cycles shorter than that of the tracking error signal TE. The A/D converter 11 standardizes the sampled value and generates error data ER having an appropriate number of bits. The bit having the uppermost order in the error data (code bit ER 0 ) indicates the polarity of the tracking error signal TE. The other bits of the error data ER indicate the amplitude of the tracking error signal TE. The polarity of the tracking error signal TE is determined by the A/D converter 11 using the intermediate potential of the ground potential value and the power supply potential value as a boundary value. The intermediate potential is set such that it coincides with the threshold value used when digitizing the tracking error signal TE and generating the track jump signal TJ.
The register 12 stores fixed data CV, the number of bits of which is the same as the tracking error signal TE. The fixed data CV is the error data ER corresponding to the tracking error signal TE, for example, when the amplitude is null. The selector 13 receives the error data ER from the A/D converter 11 and the fixed data CV from the register 12 . The selector 13 selects either the error data ER or the fixed data CV and sends the selected data to the drive signal generator 16 . The register 12 need only fix each of the bits of the fixed data at a high level or a low level. Thus, each bit of the fixed data CV of the register 12 may be generated by a connection to a power supply potential or a ground potential.
The track jump signal TJ and the off track signal OT, which are obtained by digitizing the tracking error signal TE, are both sent to the movement direction determiner 14 . The movement direction determiner 14 determines the moving direction of the pickup 3 based on the difference between the phases of the signals TJ, OT. The movement direction determiner 14 sends a direction instruction signal DR to the XOR gate 15 in accordance with the determination result of the movement direction determiner 14 .
For example, if the phase of the off track signal OT is delayed from that of the track jump signal TJ by 90°, the movement direction determiner 14 determines that the pickup is moving in an outward direction of the disc. In this case, the movement direction determiner 14 causes the direction instruction signal DR to rise. On the other hand, if the phase of the off track signal OT is ahead of the track jump signal TJ by 90°, the movement direction determiner 14 determines that the pickup is moving toward the center of the disc 1 . In this case, the movement direction determiner 14 causes the direction instruction signal DR to fall. The direction instruction signal DR remains the same until the pickup 3 reaches the target position. Thus, it does not matter whether the timing of the timing jump signal TJ differs from that of the tracking error signal TE.
The XOR gate 15 receives the code bit ER 0 of the tracking error signal TE and the direction instruction signal DR and sends its output to the selector 13 as a selection signal SL. With reference to FIG. 6, when the direction instruction signal DR is high, that is, when the pickup 3 is moved in an outward direction of the disc 1 , the XOR gate 15 sends the selection signal SL, which is obtained by inverting the value of the code bit ER 0 , to the selector 13 . The fixed data CV is selected when the selection signal SL is low. In other words, the error data ER is replaced by the fixed data CV when the code bit ER 0 indicates negative polarity of the tracking error signal TE. Hence, the amplitude of the tracking error signal TE s for negative polarity is null. If the direction instruction signal DR is low, the XOR gate 15 sends the code bit ER 0 directly to the selector 13 . Then, since the selector 13 selects the fixed data CV when the selection signal SL is low, the error data ER is replaced by the fixed data CV when the code bit ER 0 indicates positive polarity of the tracking error signal TE. Hence, the amplitude of the tracking error signal TE s for positive polarity is null. The tracking error signal TE s is formed by the digitized error data ER and the fixed data CV. The difference in the timing of the selection signal SL, which controls shifting of the selector 13 , and the error data ER is caused only by the delay of the XOR gate 15 . The selector 13 functions properly when the delay time of the XOR gate 15 is shorter than the sampling cycle of the A/D converter 11 .
The drive signal generator 16 generates an acceleration signal in response to control data AC from a control system (not shown), which causes movement of the pickup 3 . The drive signal generator 16 also generates a brake signal in response to the error data ER or fixed data CV received from the selector 13 . Afterward, the drive signal generator 16 synthesizes the acceleration and brake signals to generate the drive signal TD and sends the drive signal TD to the actuator 4 . The drive signal TD includes a brake signal generated by limiting the error data ER to one of the polarities in accordance with the code bit ER 0 . Accordingly, with reference to FIG. 7, when the pickup 3 is moved radially along the disc 1 , the pickup 3 is decelerated if the tracking error signal TE represents the positive polarity, that is, if the pickup 3 is located in a zone extending from a substantially midway position between two adjacent pits to the central portion of the next pit. The pickup 3 moves in the direction indicated by the arrow in FIG. 7 .
It is preferable that the stopping position of the pickup 3 coincide with the center of the pits. However, if the pickup 3 stops at a position somewhat offset from the bit center, the servo controller 6 moves the pickup 3 to the pit center when the disc 1 starts to rotate.
A tracking servo circuit 20 according to a second embodiment of the present invention will now be described with reference to FIGS. 8 and 9. The second embodiment employs an inverter 18 in lieu of the register 12 of the first embodiment. The inverter 18 is preferably formed with a plurality of inverter circuits.
The inverter 18 receives the error data ER sent from the A/D converter 11 , generates inverted error data IER by inverting each bit of the error data ER, and sends the inverted error data IER to the selector 13 . The inverted error data IER is handled in the same manner as the fixed data CV illustrated in FIG. 5 . That is, the selector 13 selects either the error data ER, which is received directly from the A/D converter 11 , or the inverted error data IER, which is received via the inverter 18 , and sends the selected data to the drive signal generator 16 . The drive signal generator 16 then uses the same procedures as the first embodiment (FIG. 5) to generate the drive signal TD.
With reference to FIG. 9, the tracking servo circuit 20 generates the selection signal SL by inverting the code bit ER 0 when the direction instruction signal DR is high. The error data ER is replaced by the inverted error data IER when the code bit ER 0 indicates negative polarity of the tracking error signal TE. This causes the tracking error signal TE s to maintain a positive value. If the direction instruction signal DR is low, the code bit ER 0 is used as the selection signal SL. The error data ER is replaced by the inverted error data IER when the code bit ER 0 indicates positive polarity of the tracking error signal TE. This causes the tracking error signal TE s to maintain a negative value. The tracking error signal TE s is formed by the digitized error data ER and inverted error data IER.
In the second embodiment, the difference between the timing of the selection control signal SL, which controls the shifting by the selector 13 , and the timing of the error data ER is caused only by the delay of the XOR gate 15 . Thus, the selector 13 functions properly, like in the first embodiment.
In the first embodiment, the register 12 sends the fixed data CV to the selector 13 , while in the second embodiment, the inverter 18 sends the inverted error data IER to the selector 13 . In the first and second embodiments, replacement data may be generated by an amplifier (which is preferably a multiplier) and sent to the selector 13 together with the error data ER. In this case, the gain of the amplifier is set at “0” to perform the same processing as the first embodiment and set at “−1” to perform the same processing as the second embodiment.
A tracking servo circuit 30 according to a third embodiment of the present invention will now be described with reference to FIGS. 10 and 11. The description will center on those parts which differ from the first embodiment. The tracking servo circuit 30 includes a first multiplying device 12 a and a second multiplying 12 b which are arranged between the A/D converter 11 and the selector 13 .
The first and second multiplying devices 12 a , 12 b are provided with first and second multipliers A 1 , A 2 , respectively. The first and second multipliers A 1 , A 2 are set independently from each other and in accordance with the operational characteristics of the mechanism that moves the pickup. The first and second multiplying devices 12 a , 12 b multiply the error data ER sent from the A/D converter 11 with the first and second multipliers A 1 , A 2 to generate first and second product data MP 1 , MP 2 , respectively. If the first multiplier A 1 is set at a positive value, the second multiplier A 2 is set at a negative value. Thus, the polarity of the second product data MP 2 obtained from the second multiplying device 12 b is inverted relative to the error data ER. The selector 13 selects one of the product data MP 1 and MP 2 obtained from the associated first and second multiplying devices and sends the selected data to the drive signal generator 16 .
The XOR gate 15 receives the code bit ER 0 of the tracking error signal TE and the direction instruction signal DR and sends its output to the selector 13 as a selection signal SL. With reference to FIG. 11, when the direction instruction signal DR is high, the XOR gate 15 sends the selection signal SL, which is obtained by inverting the value of the code bit ER 0 , to the selector 13 . The selector 13 selects the first product data MP 1 when the code bit ER 0 indicates positive polarity of the tracking error signal TE. If the code bit ER 0 indicates negative polarity of the tracking error signal TE, the selector 13 selects the second product data MP 2 . This causes the tracking error signal TE s to maintain a positive value. If the direction instruction signal DR is low, the XOR gate 15 sends the code bit ER 0 directly to the selector 13 as the selection signal SL. The selector 13 selects the second product data MP 2 when the code bit ER 0 indicates positive polarity of the tracking error signal TE. As mentioned above, the polarity of the second product data MP 2 is inverted relative to the error data ER. This causes the tracking error signal TE s to maintain a negative polarity. In the actual circuit, the tracking error signal TE s is formed by the digitized error data ER and the inverted error data IER.
The drive signal generator 16 generates an acceleration signal in response to control data AC from a control system (not shown), which commands the movement of the pickup 3 . The drive signal generator 16 also generates a brake signal in response to the data MP 1 of MP 2 acquired from the selector 13 . Afterward, the drive signal generator 16 synthesizes the acceleration and brake signals to generate the drive signal TD and sends the drive signal TD to the actuator 4 .
The drive signal TD includes a brake signal limited to only one of the polarities in accordance with the code bit ER 0 . Accordingly, with reference to FIG. 12, when the pickup 3 is moved radially along the disc 1 , the pickup 3 undergoes a first deceleration if the tracking signal TE represents the positive polarity, that is, if the pickup 3 is located in a zone extending from a substantially midway position between two adjacent pits to the central portion of the next pit. The pickup 3 undergoes a second deceleration if the tracking signal TE represents the negative polarity, that is, if the pickup 3 is located in a zone extending from the central portion of the next pit to a substantially midway position between the adjacent two pits. The first and second deceleration processes are determined by the first and second multipliers A 1 , A 2 which are set by the first and second multiplying devices 12 a , 12 b . Accordingly, the first and second deceleration processes are independent of each other. The pickup 3 moves in the direction indicated by the arrow indicated in FIG. 12 . It is preferable that the stopping position of the pickup 3 coincide with the center of the pits. However, if the pickup 3 stops at a position somewhat offset from the bit center, the servo functions to move the pickup 3 to the pit center when the disc 1 starts to rotate.
In the third embodiment, the difference between the timing of the selection control signal SL, which controls the shifting of the selector 13 , and the timing of the error data ER is caused only by the delay of the XOR gate 15 . Thus, the selector 13 functions properly, like in the first embodiment. Furthermore, when the pickup 3 moves radially along the disc 1 , two types of deceleration processes are performed. Hence, very accurate control of the pickup 3 is performed.
In the third embodiment, deceleration processes are carried out substantially continuously during the movement of the pickup 3 . However, one of the first and second multipliers A 1 , A 2 may be set at zero. In this case, the pickup 3 may be decelerated either when the pickup 3 is located in a zone extending from a central portion of a bit to a substantially midway position between the two adjacent pits or when the pickup 3 is located in a zone extending from a substantially midway position between two adjacent pits to the central portion of the next pit.
In the first to third embodiments, one of the polarities of the tracking error signal can be acquired at an accurate timing. A braking force corresponding to the acquired tracking error signal is applied to the pickup 3 when the pickup 3 is moving radially along a disc 1 . This accurately stops the pickup 3 .
In the third embodiment, the braking force at two different periods are set separately from each other for fine control of the braking force. This decreases the time required for the pickup 3 to move between tracks and improves the response speed during track jumps.
It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.
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A tracking servo circuit for stopping movement of a pickup device at a target position on a recording track of a recording medium, such as a CD, includes an A/D converter that generates error data from a tracking signal. The tracking error signal has a positive value when the pickup device is located at a first side of the recording track and a negative value when the pickup device is located on the opposite side of the recording track. The error data includes a code bit indicating the polarity of the tracking signal. A selector control circuit generates a selection signal using the code bit. A selector connected to the A/D converter and the selector control circuit selects either the error data or a fixed data value based on the selection signal. A drive signal generator receives the selected data and generates a drive signal to stop the radial movement of the pickup device.
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This application is a continuation of application Ser. No. 07/889,905, filed May 29, 1992, now abandoned.
This invention relates to artificial bone implants and more specifically to implants used for cranioplasty.
BACKGROUND OF THE INVENTION
Plastic surgeons often are required to augment or repair bone structure in reconstructive surgery to correct injury or birth defects. Bone augmentations are also routinely performed in cosmetic surgery. For facial bone augmentations, surgeons will most often choose natural bone from the patient to provide graft material. These grafts, called autogenous grafts, because they are taken from the patient, allow for the ingrowth of new bone and improve the chances of graft acceptance. Autogenous grafts have several drawbacks which include the need for a second operative site. The donor site can cause considerable postoperative discomfort and unsightly depressions. These imperfections are most notably seen in graft sites in the cranium.
When a surgeon elects to harvest natural bone from the section of the cranium for a graft, after suitably preparing the epidermal layer, the surgeon first makes an incision through the scalp and connective tissue or periosteum to reveal the surface of the outer table of the cranium of the patient. Using a bone cutting tool, the surgeon cuts into the cranium but is careful not to penetrate the entire thickness of the cranium. The skull in this area is relatively thick and it is possible to obtain a bone section up to 5 mm thick from the region. The surgeon frees and removes the tissue from the area which will be later transplanted or grafted to the facial area in need of augmentation. This procedure results in the creation of defects which have varying sizes and shapes as dictated by the need for material in the operative site. The defects are irregularly shaped due to the contours of the outer surface of the cranium and the varying depth of the incisions formed by the surgeon. The defects are defined by the peripheral edges of the cranium's outer surface sidewalls which extend radially into the cranium and communicate with a bottom surface or bed. Removal of the bone compromises the protection provided by the cranium because the remaining portion of the cranium which lays beneath the bed of the tissue harvest site is thinner. Removal of the bone graft tissue also results in a ridge defined by the peripheral edges of the depression on the outer surface of the cranium. This ridge presents an undesirable risk of further injury and is cosmetically unappealing.
Cranioplasty is also necessary to correct defects in the cranium which are formed as a result of trauma and other surgery in response to disease. For example, a surgeon may cut entirely through the outer table of the cranium revealing the underlying brain in order to remove a meningioma or osteoma. The bone tissue removed by the surgeon must be replaced with a suitable replacement matrix. In cases of severe trauma, portions of the cranium may be fractured beyond use or entirely lost. Material placed in a defect of this type must be supported to ensure that it will not put pressure on the brain. In such situations, a suitable implant must be easily conformed to these sites.
Preferably, a defect caused by trauma or surgery should be completely filled with an implant which is the same size and shape of the bone tissue that has been removed or lost. In order to protect the brain, the material should be sufficiently hard, yet the implant must have some flexibility to enable it to conform to the contours of each patient's cranium. A porous material is preferred to allow for tissue ingrowth which will permanently stabilize the implant in position. Another important consideration is to provide a material which is relatively easy to shape to fit the dimensions of the void or defect so as to allow the surgeon to quickly treat the area and avoid complications.
Although natural bone is the preferred choice for many applications, it is not a practical material to treat the defects in the cranium as described above. Natural bone is difficult or impossible to shape to the desired configuration and there is not a readily available source of the material. Resorption is also a problem known to occur with natural bone or bone derived implants as well as deformation. In instances of both resorption and deformation, an implant does not retain its intended shape and further corrective surgery may be required.
In response to the need for suitable bone implant materials there have been a number of synthetic materials developed for use as artificial bone or similar support tissue. These materials have included metals, ceramics, plastics and other polymers and a number of combinations thereof. Synthetic materials are easy to obtain, maintain, can be biologically inert and do not involve additional trauma to the body. Some synthetic materials are easy to shape to desired configurations and most can be made porous like natural bone. Porous implant materials are favored because of their ability to unite with live bone fragments and allow for tissue ingrowth. Tissue ingrowth stabilizes the implant and provides strength to the interface between the implant and adjoining tissue. If foreign implant materials are left permanently in place and are not adequately stabilized they can become dislodged which can cause irritation or impairment. Biodegradable implant materials are sometimes advantageous because the they will eventually degrade and allow tissue to completely fill the void.
Alloplastic materials continue in popularity as bone implants despite relatively high complication rates and difficulty in shaping the currently available implant materials. One widely used material methylmethacrylate, a thermoplastic material, has been linked to tissue damage and the release of a toxic monomer which has been implicated in adverse reactions. Furthermore methylmethacrylate is brittle and has been connected with bone reabsorption, loosening of the implant and infection.
High density porous polyethylene has been successfully used in the reconstruction of maxillofacial trauma patents and has been specifically used for orbital reconstruction and onlay grafting. It is porous, biologically inert, relatively hard and will not degrade. Porous polyethylene is the synthetic material of choice for applications which require rigidity due to its tolerance, resistance to infection and hardness, however it can not be easily shaped to fill cranial defects. Polyethylene blocks have a low modulus of elasticity and would be difficult to shape for use in sections thick enough to treat cranial defects.
Softer plastic materials such as polytetraflouro-ethylene ("PTFE") are not suitable for use in cranioplasty because they do not provide sufficient protection until ossification is complete and ossification in compact bone tissue occurs at a very slow rate. In instances where the entire outer table is removed, ossification will only occur from the sides of the implant.
For example, Proplast™, a carveable and flexible composite material made of PTFE and carbon or aluminum oxide, has been commercially available for use as an implant however it does not provide the necessary structural integrity for cranioplastic procedures. Proplast employs a biodegradable agent which gives the material its rigid characteristics. After implantation in the body, the agent degrades and the rigid character of the material is lost. Proplast can also present complications due to the presence of carbon and aluminum oxide which are reactive. Lastly, carbon impregnated material can sometimes be seen through the skin when planted subcutaneously.
Silicone, which is popular for facial reconstructions because of its elasticity, has been custom fabricated for use in cranial contour restoration. However, silicone is not hard enough to mimic the cranium and there has been recent controversy concerning the safety of silicone as an implant material. In animals, silicone has been associated with prolonged local fluid accumulation and resorption of the underlying bone requiring the patient to undergo additional corrective surgery.
Hydroxyapatite has been a popular implant material because of it ability to provide for good bone ingrowth however its use is not a practical solution to the correction of cranial deformities. Hydroxyapatite has a low modulus of elasticity and is difficult for the surgeon to manipulate. Complications associated with this type of surgical implantation require time which is expensive and increases the chances of complications.
Polymers such as polyacetic acid as described in U.S. Pat. No. 4,186,448 have been used to successfully treat voids formed as a result of the removal of teeth or central bone tumors and treating maxillofacial trauma. Polylacetic acid has been formed in thin sheets and used in place of "Teflon"™ or Superamid to provide support for the orbital floor. Polyacetic acid however degrades over time and does not provide a permanent scaffold structure to provide elevation and hardness over time.
Successful metals used as bone implants include stainless steel and titanium alloys. Initial problems associated with the lack of porosity have been overcome by employing mesh or by advanced sintering processes which leave a porous substrate. Cranioplasty with metals, such as titanium mesh, are strong and relatively inert and have been used with success in some applications. However metals are expensive, heavy, have a high thermal conductivity and are difficult to unite with live bone. They are also difficult to conform to the desired shape and have different elastic properties than that of bone.
In the past, plates made of stainless steel or various alloys have been used to cover and protect the areas of the cranium where the bone has been partially or entirely removed as a result of surgery or injury. Although metal implants are of sufficient strength and hardness to provide adequate protection, metal is difficult to shape and conform to the natural contours of the cranium and the defect. Moreover, plates are difficult to permanently affix to the cranium and leave a hollow cavity between the outer surface of the cranium and inner bed surface. Furthermore, metal plates are difficult to affix to the cranium by adhesives or other mechanical means which results in an operation requiring more time and expense.
Ceramic implants have high compression strength, chemical, biological inertness and a porous structure but have low resistance to impact loads. Ceramic materials are generally unsatisfactory for cranioplasty because they are brittle and are liable to break upon high impact or tension. Moreover ceramics are not flexible and are difficult to shape.
There is a need for a suitable device and material to fill the void left by a bone graft from the cranium or from the removal of a cranium section. Cranial contour correction and the repair of defects in the cranium has no clearly defined solution. Existing operative methods are time consuming and often yield unsatisfactory long term results. Furthermore the implant must be relatively easy to employ and present few complications. The implant must be strong, durable and bio-compatible yet should be easy to mold and shape to the dimensions of the depression or defect. The implant material should be flexible enough to roughly conform to the shape of the cranium. Preferably the material should be porous to enable the implant to receive new ingrowth of bone growth and to be secured in place.
The object of the present invention is to provide an implant design to easily fill the void in the cranium which results from autogenous graft operations. Another object of the invention is to provide a suitable implant that can be used to correct any defect in the cranium caused by trauma or other means. A further object of the invention is to provide an implant which is hard and durable, yet be flexible enough to be able to conform to the natural contours of the cranium.
A further object is to provide a device that is easy to shape to the dimensions of the void yet have sufficient hardness to serve as a protective shield. A further object of the invention is to provide a device that is porous to enable new ingrowth into the device to allow for permanent fixation.
Still another object of the invention is to provide a design which allows for both flexibility and projection.
SUMMARY OF THE INVENTION
In accordance with the invention, a thin implant with a smooth upper surface and a plurality of conical extensions projecting from the lower surface is provided. The structure allows the implant to be flexed in any direction within the range of the outer diameter of the distal end of each projection. Further flexation is prevented by the interference with neighboring cones. To properly fit in the defect in the bone, the device can be shaped so that the uneven surface on the graft bed is substantially filled with the implant material. A one-piece porous substrate of polyethylene or other plastic which can be easily cut and shaped with standard surgical scissors or a bone cutter is preferred, although the implant could be constructed of other materials.
The implant material has pores of a sufficient size and shape to allow for growth of new bone tissue into the prothesis. Bone growth can permanently affix the prothesis in the defect thereby dispensing with the need for permanent adhesives or mechanical attachment means such as screws.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of the implant according to the invention;
FIG. 2 is an enlarged cross section view of the implant material of the invention through the conical extensions;
FIG. 3 is a the side view of FIG. 2 in a flexed position;
FIG. 4 is a side view of a human skull showing a defect located in the side of the cranium;
FIG. 5 is an enlarged cross section of the defect shown in FIG. 4 along axis 5--5; and
FIG. 6 is an enlarged cross section of the void shown in FIG. 5 with an implant adapted to conform to the dimensions of the defect.
FIG. 7 is an isometric drawing of the invention showing in phantom an array of cones distributed across the lower surface of an implant in two dimensions.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, an implant generally designated by the reference numeral 10 is made of a porous high density plastic substrate in a rectangular configuration. The plastic material is molded to dimensions to a degree 45 mm long and 30 mm wide. In this embodiment a highly porous high density polyethylene which is commercially available under the name "MEDPOR" Surgical Implant, from Porex Technologies Corp. of Fairburn, Ga. is employed to make the implant. This material is very strong, hard, completely inert and durable over time. The material has a contiguous large pore structure which allows blood to flow through and can be rapidly vascularized to permit tissue ingrowth. MEDPOR has been available for human use since 1985 and is formed by sintering pure medical grade, high density polyethylene into virtually any preformed shape. It is strong enough to provide protection for the posterior area of the cranium. Implants of this material have shown to be highly resistant to infection and are biocompatable. Although the MEDPOR surgical implant material has worked successfully for this device a number of other high density porous plastics would also be suitable for the device.
A side view of the implant as shown in FIG. 2, reveals that extending from a thin the planar region 12 are a plurality of conical extensions 14. The axial dimensions of the planar region 12 is 1 mm thick which allows the material to bend and flex. When in place, the smooth upper surface 16 will be contiguous with the outer surface 18 of the outer table of the cranium as best shown in FIG. 6. The conical extensions 14 have an axial length of 3.0 mm which result in a total axial dimension or thickness of the implant of 4.0 mm. The base of each cone which communicates with the planar region 12 has a radius of 4.0 mm and the cones taper over their 3.0 mm length to an flat end 20 having a radius of 3.0 mm. In this embodiment the base of the cones are spaced approximately 1.0 mm apart. The cones and the planar surface are made of the same material and are of one piece construction. The shape of the implant provides elevation and allows for the flexibility of the implant.
Although the preferred material is comprised of a synthetic flexible porous substrate made of high density polyethylene, any flexible substrate with sufficient hardness formed with extensions would be suitable for the implant. The presence of the extensions give the implant its ability to provide for projection or thickness while maintaining a degree of flexibility which would not be obtainable from a solid substrate of material having the equal thickness. A solid material constructed of high density polyethylene having an axial dimension of 4.0 mm to 5.0 mm would not bend to the required degree to conform to the contour of the cranium. FIG. 3 shows a cross section of the implant in a flexed position. The material is able to flex at the spaces between the cones. The shape of the implant permits flexibility of the planar surface in any direction perpendicular to the planar surface. The conical extensions allow a relatively hard substrate to achieve a high profile and substantially fill a cranial defect area. The design also permits a surgeon to cut the implant with relative ease because both the planar region and conical ends are relatively thin. Thus, the surgeon can easily cut the top surface of the implant to fit the area and adjust the height by cutting the conical projections.
Although the implant was specifically intended for use on calvarial bone graft donor site deformities, the implant can be used for a variety of cranio-facial applications. FIG. 4 shows the location of a typical graft harvest site bed 20 which would remain from tissue harvesting although the graft harvest site could conceivably be from anywhere on the cranium. Cranial deformities of sizes from small to medium are best treated with this preformed implant. Larger defects could be treated by the custom construction of a similar implant based on the precise dimensions of the defect.
In operation, after a surgeon removes graft bone tissue a defect in the cranium remains. As shown in FIG. 5, an enlarged cross section of a harvest graft site 23 in the cranium 22, the defect is typically asymmetrical and has varying depths. The thickness of the cranium 22 from the outer surface 24 to the inner surface 26 is approximately 6.0 mm in the rear area of the cranium where grafts are typically harvested.
The surgeon will next cut a planar section of the implant material to roughly conform to the shape of a depression or void in the cranium. The surgeon may use a stencil to trace the shape of the defect and transfer the pattern to the upper flat surface of the implant. Using a scalpel or surgical scissors, the surgeon next trims the implant to closely conform to the shape of the defect. In the event part of the implant does not properly fit, any protruding edges can be removed with a scalpel. The surgeon then seats the implant to determine if any conical extensions must be trimmed to establish the proper height. The edges of the implant 28 must align and make a smooth transition with the outer surface of the cranium 30.
As shown in FIG. 6, a number of conical extensions have been trimmed to varying degrees at areas A, B and C and the implant substantially fills the defect. The planar section of the implant is in contact with the lateral walls 30 of the cranium and the conical extensions contact the bottom of the graft bed 32. After a fit is established with good edge to edge contact, screws can be obliquely set through the implant to firmly secure the device in place. For additional support, the surgeon can first create a seat for the implant on the outer table with a low speed bur. As an alternative to screws, the implant can be held in place by pressure fitting within the edges of the cranial opening or with wire sutures until ossification permanently stabilizes the implant.
Although the elasticity of the implant will depend on the actual material from which the implant is constructed, "MEDPOR" is somewhat elastic and after flexation tends to return to its original shape. Because of its elasticity, it is recommended to retained the device in place with wire sutures or surgical screws in order to keep the device in a fixed position until it is stabilized by tissue ingrowth. An implant made of MEDPOR™ can be heated in a solution of physiologic saline to allow for easier bending and, upon cooling, the implant will retain is new shape. The device can also be forced fit within the radial sidewalls of the defect which will retain the implant in position until the surrounding tissue grows into the pores. Once new bone and soft tissue grows into the porous structure, the implant is adequately stabilized.
When the implant is placed in edge to edge engagement with the outer table of the cranium, rapid bone growth into the implant occurs which can reach up to several millimeters. The ingrowth of this bone tissue forms a strong and stable connection between the cranium and the implant. In the treatment of calvarial graft donor sites, the surgeon can take advantage of a bed graph site which can initiate ingrowth of new bone material from both the lateral walls 30 and bottom of the bed site 32. Tissue from the scalp or periosteum can penetrate the top surface 16 of the implant to provide additional stability to the implant.
The shape of the implant allows limited flexibility while retaining thickness. In instances where the void communicates with the dura, the dura tissue can grows upward into the substrate and the voids 34 located between the conical extensions. The outer table of the cranium grows into the porous substrate from the lateral sidewalls of the defect and can become ossified. Tissue ingrowth from each of the contiguous surfaces Permanently stabilizes the implant in the defect.
Having thus described the present invention and its preferred embodiment in detail, it will be readily apparent to those skilled in the art that further modifications to the invention may be made without departing from the spirit and scope of the invention as presently claimed.
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A implant for cranioplasty made of porous high density polyethylene is provided. The implant has a smooth upper surface and a lower surface characterized by a plurality of conical extensions. The implant is flexible so that it can conform to the contour of the cranium and can be cut with a scalpel or surgical scissors or bone cutters. The shape of the implant allows a surgeon to easily adapt the implant to fit into cranial defects such as those caused by harvesting bone grafts.
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FIELD OF THE INVENTION
[0001] The present invention relates, in general, to medical devices and, in particular, to medical devices and related methods for the treatment of sinus conditions.
BACKGROUND OF THE INVENTION
[0002] The paranasal sinuses are hollow cavities in the skull connected by small openings, known as ostia, to the nasal canal. Each ostium between a paranasal sinus and the nasal cavity is formed by a bone covered by a layer of mucosal tissue. Normally, air passes into and out of the paranasal sinuses through the ostia. Also, mucus is continually formed by the mucosal lining of the sinuses and drains through the ostia and into the nasal canal.
[0003] Sinusitis is a general term that refers to inflammation in one or more of the paranasal sinuses. Acute sinusitis can be associated with upper respiratory infections or allergic conditions, which may cause tissue swelling and temporarily impede normal trans-ostial drainage and ventilation of the sinuses, thereby resulting in some collection of mucus and possibly infection within the sinus cavities. Chronic sinusitis is a long term condition characterized by persistent narrowing or blockage of one or more sinus ostia, resulting in chronic infection and inflammation of the sinuses. Chronic sinusitis is often associated with longstanding respiratory allergies, nasal polyps, hypertrophic nasal turbinates and/or deviated internasal septum. While acute sinusitis is typically caused by infection with a single pathogen (e.g., one type of bacteria, one type of virus, one type of fungus, etc.), chronic sinusitis is often associated with multiple pathogen infections (e.g., more than one type of bacteria or more than one genus of micro-organism).
[0004] Chronic sinusitis, if left untreated, can result in irreparable damage to the tissues and/or bony structures of the paranasal anatomy. The initial treatment of chronic sinusitis usually involves the use of drugs such as decongestants, steroid nasal sprays and antibiotics (if the infection is bacterial). In cases where drug treatment alone fails to provide permanent relief, surgical intervention may be indicated.
[0005] The most common surgical procedure for treating chronic sinusitis is functional endoscopic sinus surgery (FESS). FESS is commonly performed using an endoscope and various rigid instruments inserted through the patient's nostril. The endoscope is used to visualize the positioning and use of various rigid instruments used for removing tissue from the nasal cavity and sinus ostia in an attempt to improve sinus drainage.
[0006] A technique known as the Balloon Sinuplasty™ procedure and a system for performing the procedure has been developed by Acclarent Inc, of Menlo Park, Calif. for the treatment of sinusitis. A number of US patents and patent applications including U.S. Pat. Nos. 7,645,272, 7,654,997, and 7,803,150 describe various embodiment of the Balloon Sinuplasty™ procedure as well as various devices useable in the performance of such procedure. In the Balloon Sinuplasty™ procedure, a guide catheter is inserted into the nose and positioned within or adjacent to the ostium of the affected paranasal sinus. A guidewire is then advanced through the guide catheter and into the affected paranasal sinus. Thereafter, a dilation catheter having an expandable dilator (e.g. an inflatable balloon) is advanced over the guidewire to a position where the dilator is positioned within the ostium of the affected paranasal sinus. The dilator is then expanded, causing dilation of the ostium and remodelling of bone adjacent to the ostium, without required incision of the mucosa or removal of any bone. The catheters and guidewire are then removed and the dilated ostium allows for improved drainage from and ventilation of the affected paranasal sinus.
[0007] After performing a FESS or Balloon Sinuplasty™ procedure, it may be useful or necessary to irrigate the paranasal sinus. A device described in US 2008/0183128 may be used for irrigating a paranasal sinus. The irrigation catheter may be advanced through a guide catheter and into an ostium or the sinus for purposes of, for example irrigation, suctioning, substance delivery and culture retrieval.
[0008] There is a continuing need for improved methods and devices for treating the paranasal sinus. Although the irrigation catheter described above is easy to use, it would be useful to provide for irrigation of the sinuses during the Balloon Sinuplasty™ procedure.
SUMMARY OF THE INVENTION
[0009] Accordingly, in one aspect, the current invention is directed to a medical device for the treatment of a sinus opening, the medical device having a proximal end, a distal end, and a shaft system having an inflation lumen and an irrigation lumen between the proximal end and distal end. The shaft system has a proximal shaft section and a distal shaft section, an inflatable balloon on the distal shaft section and proximal to the distal end, and an irrigation tip on the distal shaft section, distal to the inflatable balloon. The irrigation tip has a tip opening and one or more radially facing openings.
[0010] In one embodiment, the medical device may have 3 radially facing openings. The radially facing openings may have a diameter of between 0.020 inches and 0.050 inches or of 0.026 inches.
[0011] In another embodiment, the inflation lumen and the irrigation lumen of the medical device are adjacent lumens. In further embodiments, the medical device includes a guide element lumen.
[0012] In still another embodiment, the irrigation tip has an irrigation tip lumen proximal of the atraumatic tip. The irrigation tip lumen has an irrigation tip lumen diameter, the tip opening has a tip opening diameter, and the irrigation tip lumen diameter is greater than the tip opening diameter. In another embodiment, the tip opening diameter is 0.037 inches and the irrigation lumen diameter is 0.042 inches.
[0013] In a further embodiment, the proximal shaft section of the medical device includes a stiffening member. In another embodiment, the stiffening member is a hypotube.
[0014] In another aspect, the current invention is directed to a system for accessing, dilating and irrigating a sinus, the system having a sinus guide catheter, a guiding element; and a medical device. The medical device has an inflation lumen, an irrigation lumen, an inflatable balloon and an irrigation tip. The inflation lumen and the irrigation lumen are adjacent lumens and the irrigation tip has a tip opening and at least one radially facing opening.
[0015] In one embodiment the medical device of the system has one or more direct visualization markers or one or more radiographic markers.
[0016] In another embodiment the medical device of the system has 3 radially facing openings. The radially facing openings may have a diameter of between 0.020 inches and 0.050 inches or of 0.026 inches.
[0017] In another embodiment, the system guiding element is selected from the group consisting of a guidewire or a sinus illumination system. In further embodiments, the medical device of the system includes a guide element lumen.
[0018] In other embodiments, the medical device of the system has an irrigation tip with an irrigation tip lumen proximal of the atraumatic tip. The irrigation tip lumen has an irrigation tip lumen diameter, the tip opening has a tip opening diameter, and the irrigation tip lumen diameter is greater than the tip opening diameter. In another embodiment, the tip opening diameter is 0.037 inches and the irrigation tip lumen diameter is 0.042 inches.
[0019] In a further embodiment, the medical device of the system has a proximal shaft section that includes a stiffening member. In another embodiment, the stiffening member comprises a hypotube.
[0020] In another aspect, the invention is directed to a packaged kit for treating a sinus opening. The kit comprises a medical device having an inflation lumen, an irrigation lumen, an inflatable balloon and an irrigation tip, the inflation lumen and the irrigation lumen being adjacent lumens and the irrigation tip having at least one radially facing opening, a balloon insertion stylet for insertion of the medical device into a sinus guide catheter, and irrigation tubing for connecting the medical device to a source of irrigation fluid.
[0021] In still another aspect, the invention is directed to a method for treating a target space in the nasal anatomy. The method includes providing a medical device having an inflation lumen, an irrigation lumen, an inflatable balloon and an irrigation tip. The inflation lumen and the irrigation lumen are adjacent lumens and the irrigation tip has a tip opening and at least one radially facing opening. The method includes inserting the medical device into a sinus guide catheter, inserting a guiding element into the medical device through the irrigation lumen, positioning the guide catheter in the nasal anatomy, advancing the guiding element into the target space of the nasal anatomy, advancing the medical device over the guiding element into the target space of the nasal anatomy, inflating the balloon to dilate a sinus opening, deflating the balloon, withdrawing the guiding element from the medical device, connecting irrigation tubing to the medical device, and delivering fluid to the target space though the tip opening and the at least one radially facing opening.
[0022] In one embodiment delivering the fluid occurs at a flow rate of between 50 ml/min and 200 ml/min or at a flow rate of between 75 ml/min and 125 ml/min and the sinus opening may be frontal sinus opening, a maxillary sinus opening, an ethmoid sinus opening and a sphenoid sinus opening.
[0023] In another embodiment the fluid may be water, saline, contrast agents, antimicrobial agents anti-inflammatory agents, decongestants , mucous thinning agents, anesthetic agents, analgesic agents, anti-allergenic agents, allergens, anti-proliferative agents, hemostatic agents, cytotoxic agents, and biological agents or combinations of any of the above.
[0024] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings, in which like numerals indicate like elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a simplified side view of a medical device according to an embodiment of the present invention.
[0026] FIG. 1A is a cross section view through line 1 A- 1 A of FIG. 1 .
[0027] FIG. 1B is an alternative embodiment of a cross section view through line 1 A- 1 A of FIG. 1 .
[0028] FIG. 2 is an enlarged view of the distal end of the medical device shown in FIG. 1 .
[0029] FIG. 3 shows a collection of sinus guide catheters useful for positioning of the sinus balloon catheters of the invention.
[0030] FIG. 4 shows a stylet for positioning the medical devices of the invention.
[0031] FIG. 5 shows irrigation tubing useful with the medical devices according to the invention.
[0032] FIG. 6 is a perspective view of a guidewire for use with the medical devices of the invention.
[0033] FIG. 7 is a perspective view of a sinus illumination system for use with the medical devices of the invention.
[0034] FIG. 8 is a side view of a medical device according to an embodiment of the present invention.
DETAILED DESCRIPTION
[0035] The following detailed description should be read with reference to the drawings, in which like elements in different drawings are identically numbered. The drawings, which are not necessarily to scale, depict exemplary embodiments for the purpose of explanation only and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.
[0036] As used herein, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein.
[0037] Medical devices according to embodiments of the present invention are beneficial in that, for example, their configuration provides for a particularly efficient preparation and treatment of a patient's sinus opening and is mechanically simple. Moreover, the simplicity of the medical devices provides for them to be manufactured in a cost effective manner. In addition, the medical device according to embodiments of the present invention is sufficiently stiff that it can be beneficially employed to access sinus anatomy followed by a convenient remodeling and irrigation of the sinus.
[0038] FIG. 1 is a simplified side view of a medical device 100 for the treatment of a sinus opening (for example a frontal sinus opening, maxillary sinus opening, ethmoid sinus opening or sphenoid sinus opening) according to an embodiment of the present invention. Although described with regard to the sinus opening, the inventions described herein may also be useful for the dilation of the Eustachian tube, repair of endo-cranial fractures, airway procedures such as subglottic stenosis dilation and other procedures of the ear, nose and throat. The medical device 100 is a sinus remodeling and irrigation catheter with an integrated shaft system 102 and a high pressure balloon 104 near the irrigation tip 106 . The shaft system 102 contains adjacent dual lumen tubing (see FIG. 1A ). By adjacent dual lumen tubing is intended that the lumens are next to each other but are spaced apart, one from the other. The inflation lumen 108 is used for inflation of the balloon with water, contrast medium or saline through inflation port 150 , and the irrigation lumen 110 permits passage of a guidewire or sinus illumination system to facilitate advancement of the medical device 100 to the target site and, further, to allow for the flow of irrigation fluid (water or saline) to the target site. In an alternative embodiment, there may be provided a third lumen, a guide element lumen 111 , such lumen being adjacent to the inflation lumen 108 and the irrigation lumen 110 (see FIG. 1 B). The irrigation lumen 110 and the guide element lumen 111 merge into a single irrigation lumen 110 in the distal shaft portion 118 of the device, proximal to the balloon 104 . The medical device 100 has an irrigation tip 106 with both a forward facing tip opening 114 and radially facing openings 112 a , 112 b and 112 c to facilitate irrigation delivery through the irrigation lumen 110 . The medical device 100 is intended to dilate sinus ostia and spaces within the paranasal sinus cavities and to provide a means to irrigate from within a target sinus for diagnostic and therapeutic purposes. The medical device 100 is designed to irrigate the sinus through the tip opening 114 and three radially facing openings 112 a , 112 b and 112 c in the irrigation tip 106 , by delivering fluid via the irrigation lumen 110 for delivery before, during, or after dilation of the sinus ostia or spaces within the paranasal sinus cavities. Further, instead of delivering fluid through the irrigation lumen 110 , a vacuum may be applied and a culture may be obtained by suctioning through the tip opening 114 or the radially facing openings 112 a , 112 b and 112 c . By radially facing openings is intended that the flow through the openings may be at 90 degrees from the flow through the tip opening, but is may also be at 30, 45 or 60 degrees or other angles between 0 and 90 degrees, and the openings may be round or non-round such as oval or slot-shaped.
[0039] The sinus balloon 104 is designed to be non-compliant or semi-compliant. The diameter of the non-compliant balloon does not vary significantly with inflation pressure and that of the semi-compliant balloon will vary only to the extent that it will “hourglass” or “dog-bone” about a target region. The balloon itself may be any shape such as round, triangular, oval or square. In the embodiment shown in FIG. 1 , the balloon is round and semi-compliant. A stiffening member (in this case a hypotube 116 ) is incorporated on the proximal end of the medical device (at the distal end of the proximal shaft portion 122 ) to provide rigidity during insertion through a sinus guide catheter, as further described below.
[0040] As shown in FIG. 1 in some embodiments, direct visualization markers and/or radiographic markers may be disposed along the integrated shaft system 102 . Generally, “direct visualization markers” refers to markers that may be viewed during use with the naked eye or by use of an endoscope, while radiographic markers include radiopaque material and are viewed using a radiographic device such as intra-operative fluoroscopy. In one embodiment, at the distal end, there is a first distal radiographic marker 120 a , which has a proximal edge aligned with the location where the proximal taper 140 a of the balloon 104 meets the proximal end of the effective length 142 of the balloon 104 . There is also a second distal radiographic marker 120 b , which has a distal edge aligned with the location where the distal taper 140 b meets the distal end effective length 142 of the balloon 104 . The distance across the outside edges of the distal markers 120 a and 120 b represents the effective length 142 of the balloon 104 . The distal markers 120 a and 120 b may be platinum marker bands. In this embodiment, the distal markers help to ensure that the medical device 100 is in a straight position inside the guide during the device loading and preparation. Additional radiographic markers may be included along the shaft of the catheter and/or at the distal tip.
[0041] Direct visualization markers can be positioned in a number of locations along the integrated shaft system 102 . Although one embodiment is described here with reference to FIGS. 1 and 2 , other variations may be substituted in alternative embodiments. In one embodiment, shaft system 102 may have a dark color, such as black, dark blue, dark grey or the like, and markers may have a light color, such as white, green, red or the like. In some embodiments, markers may have different colors and/or different widths to facilitate distinguishing the markers from one another during use. This contrast in colors may facilitate viewing the markers in a darkened operation room and/or when using an endoscope inside a patient in the presence of blood.
[0042] In one embodiment, there may be a first distal shaft marker 128 (or “endoscopic marker,” since it is typically viewed during use via an endoscope) disposed on the distal shaft portion 118 of the shaft system 102 at a location such that its distal edge aligns with the location where the proximal taper 140 a of the balloon 104 meets the shaft system 102 . The extended balloon neck 134 allows the first endoscopic marker 128 to be placed on the shaft and away from any adhesive bonding used to secure the proximal end of the balloon neck to the shaft. The first endoscopic marker 128 indicates to the user the ending location of the balloon 104 and indicates that the balloon has exited the guide during a procedure. In one embodiment, the first endoscopic marker 128 may be about 2 mm wide.
[0043] A second distal shaft marker 130 is disposed on the shaft system 102 such that the distal edge of the marker is 1 cm.±.0.2 cm from the location where the proximal taper 140 a of the balloon 104 meets the shaft system 102 . This marker indicates to the user that the shaft location is 1 cm away from the end of the balloon indicating that the balloon has extended from the guide during the procedure. In one embodiment, the second distal shaft marker may be about 2 mm wide and white in color, while the first marker is about 2 mm and green in color. Of course, any of a number of different size and color combinations may be used alternatively.
[0044] A third distal shaft marker 132 is disposed on the shaft system 102 such that the distal edge of the marker is 1 cm.±.0.1 cm from the distal edge of the second distal shaft marker 130 . As shown in FIG. 1 , the third distal shaft marker is a double marker to distinguish the second and third distal shaft markers 130 and 132 one from one another. The third distal shaft marker 132 indicates the shaft location 2 cm away from the end proximal end of the balloon 104 , thus indicating the distance the balloon has extended from the guide during the procedure. In one embodiment, the two markers forming the third distal shaft marker 132 are each 0.75 mm wide and white in color, however, the size and color of the marker can be changed in alternative embodiments. The differences in the first, second and third distal shaft markers' color, length and number of marks give the indication of the relative location proximal to the balloon under endoscopic visibility. Using an endoscope, the physician user can identify the length of catheter that has been advanced and retracted out of a guide catheter and/or can approximate a location of the balloon 104 relative to patient anatomy such as a paranasal sinus ostium, other paranasal sinus opening, or other openings in the ear, nose or throat. This approximation of balloon position may be very useful in circumstances when the balloon 104 has been advanced far enough into an anatomical location that the balloon 104 can no longer be viewed via endoscope. For example, using the three endoscopic markers, the user is able to endoscopically gauge the distance the catheter has advanced into the frontal recess once the proximal portion of the balloon is no longer visible. Of course, in alternative embodiments, distal shaft markers having different numbers, sizes, colors and positions along the catheter shaft may be used.
[0045] In some embodiments, in addition to one or more distal shaft markers, one or more proximal shaft markers may be disposed along the proximal portion 122 of shaft system 102 . In general, such proximal shaft markers may be viewed directly by a physician, without using an endoscope, to indicate to the physician a location of the balloon 104 of the medical device 100 relative to a guide catheter (see i.e. catheter 200 a in FIG. 3 ) through which the medical device 100 is being advanced. As with the distal shaft markers, the proximal shaft markers may have any suitable width, color, number, position and the like. In one embodiment, for example, as shown in FIG. 1 , two proximal shaft markers 124 , 126 may have a light color to contrast with a dark colored shaft system 102 and increase visibility in a darkened operating room. The more proximal of the proximal markers 124 (or the “first proximal shaft marker”) may indicate that a tip of the medical device 100 is at a distal end of the guide catheter 200 and that the balloon 104 has exited the distal end 202 of the guide catheter as the marker 124 passes into the proximal end 204 of the guide catheter. The more distal of the proximal markers 126 (or the “second proximal shaft marker”) may indicate to a user that the balloon 104 is just proximal to a curve 206 in a guide catheter when marker 126 is located at the proximal end 204 of the guide catheter.
[0046] In one embodiment, the first proximal shaft marker 124 is disposed on the shaft system 102 such that the length from the proximal end of the proximal balloon taper 140 a to the proximal end of the first shaft marker 124 is 13.1 cm.±.0.2 cm.. The length of the first proximal shaft marker 124 can vary depending on the size of the balloon catheter and may be determined by adding the length of the irrigation tip 106 , the effective or working length 142 of the balloon 104 , and the lengths of the two balloon taper sections 140 a and 140 b . Also, the first proximal shaft marker 124 is preferably white in color, however, other light colors, such as grey, can be used as well.
[0047] The second proximal shaft marker 126 is disposed on the shaft system 102 distally from the first proximal shaft marker 124 . The second proximal shaft marker 126 is positioned such that the irrigation tip 106 of the medical device 100 is 11.4 cm.±.0.2 cm from the distal edge of the second proximal shaft marker 126 . Also, the second proximal shaft marker 126 has a length of 3 mm.±2 mm. It is preferred that the second shaft proximal marker 126 is white in color, however, other light colors, such as grey, can be used as well.
[0048] When the medical device 100 is inserted into a guide catheter 200 a , a user may visualize the first and second proximal shaft markers 124 and 126 to determine the position of the irrigation tip 106 and the balloon 104 of the medical device 100 relative to the sinus guide catheter 200 a . For instance, when the second proximal shaft marker 126 is aligned with the proximal opening 204 of the guide catheter, the user will know that the balloon 104 is proximal to the curve 206 of the guide catheter. The position of the second proximal shaft marker 126 helps to visually ensure that the medical device 100 is properly loaded into the sinus guide catheter 200 a . When the distal edge of the first proximal shaft marker 124 is aligned with the proximal opening 204 of the guide catheter 200 a , the user knows that the irrigation tip 106 of the medical device 100 is beginning to exit the guide catheter 200 a , and when the proximal edge of the first proximal shaft marker is aligned with the proximal opening 204 of the guide catheter 200 a , the user knows that the balloon is completely out of the guide catheter 200 a.
[0049] The visible markers 124 , 126 , 128 , 130 and 132 are preferably light in color, such as white as indicated above, to contrast with a dark color of the shaft system 102 , which is preferably black. The high contrast between these visible markers and the shaft helps view the markers in a low light environment. Also, the high contrast allows the user to view directly with an endoscope the markers and know where the balloon 104 is located relative to a sinus ostium. Furthermore, the color contrast is useful during the procedure when the field is full of blood and/or mucus to view the markers and know the position of the balloon. Of course, any other suitable contrasting color combination may be used. In one embodiment, for example, the shaft system 102 may be light colored, and the markers 124 , 126 , 128 , 130 and 132 may be dark colored.
[0050] FIG. 3 shows a series of sinus guide catheters 200 a - 200 f that may be used in conjunction with the medical device 100 . These guide catheters 200 a - 200 f are substantially rigid and each has a preset distal curve of 0 degrees ( 200 a ), 30 degrees ( 200 b ), 90 degrees ( 200 d ), 70 degrees ( 200 c ) or 110 degrees ( 200 e and 200 f ). Different curvatures are useable to access the ostia of different sinuses. For example, a 70 degree guide is typically used to access the ostium of a frontal sinus, a 90 or 110 degree guide is typically used to access the ostium of a maxillary sinus, etc. Each of these guide catheters 200 a - 200 f has a length of 12.7 cm. These sinus guide catheters are described in U.S. patent application Ser. Nos. 10/944,270 and 11/355,512 and U.S. patent Nos. 7,654,997 and 7,803,150 which are hereby incorporated by reference, and are commercially available as Relieva™ sinus guide catheters from Acclarent, Inc., Menlo Park, Calif.
[0051] The medical device 100 is packaged with a balloon insertion stylet 300 (see FIG. 4 ) and irrigation tubing 400 (see FIG. 5 ). The stylet 300 comprises a rounded distal tip 302 , a support shaft 304 and a proximal loop 306 . The insertion stylet 300 assists with insertion of the medical device 100 into the sinus guide catheter 200 a and is removed from the device 100 prior to advancement of the medical device 100 into the patient anatomy. The irrigation tubing 400 incorporates standard luer connectors 402 and 404 on each end and is used to attach a sterile syringe to the irrigation port 144 of the medical device 100 for sinus irrigation. Additionally, as shown in FIG. 8 , a ring 800 is provided that may be operated by the thumb or finger of a user to aid in insertion of the medical device 820 .
[0052] In the following description, the sinus guide catheter will be referred to as 200 a , but any of the guide catheters 200 b - f shown in FIG. 3 may be used. Following insertion of the medical device 100 into the sinus guide catheter 200 a , a guiding element such as a sinus guidewire 500 (i.e. Relieva Vigor® Sinus Guidewire manufactured by Acclarent Inc, Menlo Park, Calif. and shown in FIG. 6 ) or sinus illumination system 600 (i.e. Relieva Luma Sentry™ Sinus Illumination System shown manufactured by Acclarent Inc, Menlo Park, Calif. and shown in FIG. 7 ) is inserted through the irrigation port 144 of the medical device 100 and to the distal tip of the sinus guide catheter 200 a . Sinus access is achieved by positioning the sinus guide catheter 200 a in the nasal anatomy, and advancing the sinus guidewire 500 or sinus illumination system 600 into the target sinus. Once sinus access has been achieved, the medical device 100 is advanced over the sinus guidewire 500 or sinus illumination system 600 and into the target space. The endoscopic markers on the balloon catheter can be used to assist with placement. The medical device 100 is then inflated to dilate the sinus ostia. Following dilation, the balloon is deflated. The guidewire 500 or sinus illumination system 600 is removed from the nasal anatomy. A standard syringe is connected to the irrigation tubing 400 , which is connected to the irrigation port 144 of the medical device 100 . Fluid is manually delivered to the sinus through the irrigation tip 106 via the distal tip opening 114 and three radially facing openings 112 a , 112 b and 112 c of the medical device 100 , each side port having a diameter of 0.026 inches. Upon completion, the medical device 100 is retracted into the sinus guide catheter 200 a and removed from the anatomy. The medical device 100 can be prepared for additional sinus dilations and/or irrigations in the same patient. Alternatively, a suction system such as a standard syringe or other vacuum source such as a vacuum pump may be connected to the irrigation port 144 either directly and through a tubing system and the target sinus may be suctioned either before or after treatment thereof.
[0053] The medical device 100 sizes may be 3.5 mm×12 mm, 6 mm×16 mm or 7 mm×24 mm, although others are within the scope of the invention, including, but not limited to 5 mm×16 mm, 5 mm×24 mm or 7 mm×16 mm. The distal shaft portion or section 118 of the device has an inner diameter of ≧0.037 inches and the proximal shaft portion or section 122 of the device has an inner diameter of 0.042 inches. The distal edge 138 of the first endoscopic marker 128 is located 10 mm from the proximal edge 136 of the proximal balloon taper 140 a , the length from the medical device tip opening 114 to the distal end 124 a of the first shaft marker 124 is 114 mm and the distance from the proximal end 136 of the proximal balloon taper 140 a to the proximal end 124 a of the shaft marker 124 is 131 mm. The total length of the 3.5 mm medical device is 250 mm and of the other medical devices is 252 mm. The balloon inflated diameters for the medical devices are as follows: 3.5 mm for the 3.5 mm×12 mm, 6 mm for the 6 mm×16 mm and 7 mm for the 7 mm×24 mm. The balloon inflated working lengths for the medical devices are as follows: 12 mm for the 3.5 mm×12 mm, 16 mm for the 6 mm×16 mm and 24 mm for the 7 mm×24 mm. The maximum outer shaft diameter is ≦0.086 inches. The deflation time of the balloon catheter is preferably seconds. The irrigation flow rate is approximately 100 ml/min and may between ≦50 and 200 ml/min or 75 and 125 ml/min with a maximum flow rate of 250 ml/min.
[0054] The balloon 104 is made of any suitable material known in the art for inflation balloons and may be constructed of compliant, semi-compliant or non-compliant materials such as nylon (semi-compliant) and polyethylene terepththalate (PET) (non-compliant). In a particular embodiment, the balloon is constructed of semi-compliant material such as nylon. The atraumatic tip portion 146 is also made of nylon and is soft with a durometer of less than approximately 55D (often approximately 40D). The remainder of the irrigation tip is less soft (with a durometer greater than about 55D, often about 70D) than the tip portion 146 and is flexible with a longer length than prior art balloons tips in order to accommodate the radially facing openings 112 a , 112 b and 112 c . In this way, the medical device 100 is more easily inserted into the guide catheter 200 a and through the tortuous sinus anatomy. The atraumatic tip portion 146 may further contain a marker that is nylon with 20% barium sulfate and is approximately 1 mm in length or may contain any other type of radiopaque marker for fluoroscopic visualization or colored marker for direct visualization of the patient anatomy. In the particular embodiment shown in FIG. 1A , the outer shaft 148 of the medical device 100 is made of pebax. The first inner shaft 150 (comprising the inflation lumen) and the second inner shaft 152 (comprising the irrigation lumen) are made of nylon and pebax. The hypotube shaft 116 that surrounds the outershaft 148 is 304 stainless steel. The combination of materials (the nylon balloon and the adjacent dual lumen design) provides for ease of insertion of the medical device into and removal from the guide catheter 200 a (at least in part due to the smaller profile of the nylon balloon) and navigation through the tortuous sinus anatomy. Insertion into the guide catheter 200 a and navigation through the tortuous anatomy is also enhanced by the atraumatic tip that is long, soft and flexible.
[0055] Medical device 100 is configured to irrigate or suction fluids deep within the sinuses, as well as other areas within the paranasal space. Medical device 100 is sized appropriately to be delivered into adult as well as pediatric sinuses, including maxillary, sphenoid, ethmoid and frontal sinuses. Further, the devices of the invention may be useful for the treatment of the Eustachian tube or through an incision to access the middle ear. Medical device 100 can also be used to deliver diagnostic or therapeutic substances into the sinuses or other areas in the paranasal space. Examples of such diagnostic or therapeutic substances include, but are not limited to: contrast agents, pharmaceutically acceptable salt or dosage form of an antimicrobial agent (e.g., antibiotic, antiviral, anti-parasitic, antifungal, etc.), a corticosteroid or other anti-inflammatory (e.g., an NSAID), a decongestant (e.g., vasoconstrictor), a mucous thinning agent (e.g., an expectorant or mucolytic), an anesthetic agent with or without vasoconstrictor (e.g., Xylocaine with or without epinephrine, Tetracaine with or without epinephrine), an analgesic agent, an agent (anti-allergenic agent) that prevents of modifies an allergic response (e.g., an antihistamine, cytokine inhibitor, leucotriene inhibitor, IgE inhibitor, immunomodulator), an allergen or another substance that causes secretion of mucous by tissues, anti-proliferative agents, hemostatic agents to stop bleeding, cytotoxic agents e.g. alcohol, and biological agents such as protein molecules, stem cells, genes or gene therapy preparations.
[0056] Referring now to FIG. 1 , in one embodiment, medical device may include a forward facing tip opening 114 three radially facing openings 112 a , 112 b , and 112 c , on irrigation tip 106 spaced 120 degrees apart, with the inner diameter of the forward facing tip opening being 0.037 inches and each of the side openings having a inner diameter of 0.026 inches and the inner diameter of the irrigation lumen proximal of the atraumatic tip is about 0.042 inches. Alternative embodiments may include any suitable alternative number of side openings distributed in any suitable pattern such as a helical pattern. In one embodiment, a first side opening may be placed at about 2.5 mm from the distal end of medical device 100 , a second side opening may be placed at about 3.5 mm from the distal end of medical device 100 , and a third side opening may be placed at about 4.5 mm from the distal end of medical device 100 , with each of these measurements being from the distal end to approximately the center of each side opening. The length of the irrigation tip from the distal end of the medical device 100 to the distal end of the balloon 104 is approximately 7 mm. Each side opening may have any suitable diameter in various alternative embodiments. For example, in one embodiment, each side opening may have a diameter of between about 0.020 inches and about 0.050 inches and or between about 0.030 inches and about 0.040 inches and or about 0.033 inches, so long as the diameter of the irrigation lumen of the irrigation tip proximal of the atraumatic tip is larger than the diameter of the forward facing tip opening.
[0057] In an alternative embodiment, the medical device 100 may contain an integrated guidewire such that there is no irrigation from the distal end of the device, but only from the radially facing openings.
[0058] The invention has been described with reference to certain examples or embodiments of the invention, but various additions, deletions, alterations and modifications may be made to those examples and embodiments without departing from the intended spirit and scope of the invention. For example, any element or attribute of one embodiment or example may be incorporated into or used with another embodiment or example, unless otherwise specified or if to do so would render the embodiment or example unsuitable for its intended use. Also, where the steps of a method or process have been described or listed in a particular order, the order of such steps may be changed unless otherwise specified or unless doing so would render the method or process unworkable for its intended purpose. All reasonable additions, deletions, modifications and alterations are to be considered equivalents of the described examples and embodiments and are to be included within the scope of the following claims.
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A medical device, and a system and packaged kit containing the medical device for the treatment of a sinus opening is described. The medical device comprises a proximal end, a distal end, and a shaft system having an inflation lumen and an irrigation lumen the proximal and. The shaft system has a proximal shaft section and a distal shaft section. An inflatable balloon is attached to the distal shaft section in a position that is proximal to said distal end. The irrigation tip is distal to the balloon on the distal shaft section and has a tip opening and one or more radially facing openings. A method for treating a sinus opening includes inserting a system that includes the medical device, a sinus guide catheter and a sinus guide element into a patient's anatomy, dilating the sinus opening and irrigating a target in the nasal anatomy.
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FIELD OF THE INVENTION
This invention relates to forestry and wood logging operations, and more particularly to a skyline transport system for transporting cut trees slopewisely of a hill and other loads.
BACKGROUND OF THE INVENTION
In wood logging operations, labour costs constitute a growing concern among operators. For instance, the slopewise transportation of tree trunks usually comprises a sky-line extending between an upper and a lower base anchor, a carriage suspended from the skyline and a dragline extending through the carriage, then along the skyline and driven by a hoist at the upper anchor base. An operator is always required at said upper anchor base, to pay out and retrieve the drag line which serves to drag the cut trees and also to move the carriage along the skyline.
OBJECTS OF THE INVENTION
An object of the invention is to substantially reduce the labour costs associated with logging operations by eliminating the operator at the upper anchor base.
Another object of the invention is to provide a transport system in which both anchor bases are readily movable transversely of the hill to permit logging along successive slopewise zones.
SUMMARY OF THE INVENTION
The invention relates to a skyline-suspended carriage system for transporting a load slopewisely of a hill, comprising a skyline, anchored to and extending between an upper and a lower anchor point; an elongated carriage having an uphill end and downhill end, an uphill and downhill carriage suspending idle pulley mounted at the uphill and downhill ends of said carriage respectively and engaging longitudinally spaced portions of the top of the skyline, and an intermediate driving pulley mounted on said carriage for moving the carriage along the skyline, said driving pulley located adjacent said downhill idle pulley and spacedly from said uphill idle pulley and engaging the bottom of said skyline, the topmost sector of said driving pulley being higher than the straight line joining the lowermost sectors of the two idle pulleys so that the skyline is wrapped around said driving pulley through a sector of a least 30°; and power means mounted in said carriage for rotating said driving pulley.
Preferably, the system further includes a power operated hoist mounted in the carriage, a pay-out pulley carried by said carriage at its uphill end below said skyline and below said uphill idle pulley, and a drag line wound on said hoist and trained on said pay-out pulley for securing a load to be pulled by the carriage.
In the first configuration of the three pulleys, the straight line joining the axes of the drive pulley and of the downhill pulley is substantially normal to the line joining the axes of the drive pulley and of the uphill pulley. In a second configuration of the three pulleys, their axes lie on a straight line. The first configuration of the pulleys is used for a high gradient slope while the second configuration is used for a low gradient slope.
The power means preferably includes a transmission means having a drive pinion rotatably mounted in a fixed position in the carriage, and a sprocket meshing with the pinion, co-axial with and fixed to said driving pulley. The carriage further includes a first, a second and a third journal means, said first and second journal means located on a first straight line passing through the axis of said upstream idle pulley and generally extending along the top of said carriage, said second journal means disposed at a distance from the drive pinion axis equal to the distance between the drive pinion axis and said first journal means, the straight line joining the first and third journal means being generally normal to said first straight line, the axle of said driving pulley capable of being journalled in either one said first and second journal means, the axle of said downhill idle pulley capable of being selectively journalled in either one of said first and third journal means. In said first pulley configuration, said drive pulley and said downhill pulley are journalled in said first and third journal means respectively. In said second pulley configuration, said downhill pulley and said drive pulley are journalled in said first and second journal means respectively.
The invention also comprises the skyline suspended carriage system as defined above in combination with two anchor points each being a self-propelled vehicle, the lower one of said vehicles being a self-propelled power shovel including a turntable carrying a hydraulic boom provided with an end bucket adapted to abut firmly against the ground towards the direction of the skyline to prevent shovel overturning under the skyline tension, a mast extending from the boom and carrying an idle pulley on which the skyline is trained, and a hoist on the turntable on which one end of the skyline is wound.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a load-carrying system according to the invention, spanning the slope of a hill;
FIG. 2 is an enlarged side elevational view of the carriage of the system of the invention;
FIG. 3 is an end elevation of the carriage, taken from perspective 3 of FIG. 2;
FIG. 4 is a longitudinal section taken along line 4--4 of FIG. 3;
FIG. 5 is a broken view of the upper section of FIG. 4, but for a second arrangement of the sheaves, used when the system is installed on a low-gradient slope; and
FIG. 6 is a plan view taken from perspective 6 of FIG. 5; and
FIG. 7 is a section taken along line 7--7 of FIG. 6;
DETAILED DESCRIPTION OF THE INVENTION
Carriage 10 consists of an elongated, rigid, box-like frame 12 through which longitudinally extends a single skyline cable 16. Cable 16 is destined to be mounted at both end sections thereof to two horizontally spaced, vertically offset, upper and lower ground anchor means, 18, 20, respectively. Mounting means, detailed later, are provided to suspend the carriage frame 12 from the cable 16, whereby the carriage frame becomes a skyline suspended carriage. A load-grabbing and retaining drag-line system, also detailed later, enables the carriage 10 to pull or carry a heavy load, e.g. a number of wooden logs or harvested trees W, via a drag-line 17, between the two anchor means 18, 20, normally downhill.
More particularly, upper anchor means 18 includes a self-propelled vehicle, e.g. a skidder 22, standing on a plateau P near the slope S of an underlying hill H. The back of skidder 22 faces the slope S, so that its rear wheels 24 be nearest to the frontward edge of plateau P while its heaviest rear part is farthest therefrom. A tree stump (not shown) or a heavy, preferably ground anchored abutment block, 26, should be installed on plateau P in front of the skidder rear wheels 24, to prevent downhill motion of skidder 22 under the load W sustained through skyline 16, as will be seen. The upper section of skyline 16 is trained on an idle pulley 36 and wound around the hoist 28 of the skidder 22. A counterweight 37 is preferably carried by the front of skidder 22 to prevent its overturning under skyline tension. It should be noted that skidder 22 can be positioned farther away from the plateau front edge than shown with skyline 16 resting on the ground at said front edge.
Lower anchor means includes another self-propelled vehicle, namely a power shovel 30 located in a valley V and in substantial register with skidder 22. The back of the turnable 32a of power shovel 30 carries a hoist 32, around which is wound the lower section of skyline 16. The hydraulic boom 34 of shovel 30 is positioned so that bucket 35 abuts against the ground V towards the slope S, as illustrated in the drawings, to prevent shovel overturning under skyline tension.
Idle pulleys 36, 38 engaged by skyline 16, should be carried by substantially upright masts 40, 42 upwardly projecting from the frontmost end of skidder 22 and from the elbow portion of the inner boom of shovel 30, respectively. Either one or both hoists 28, 32 can be actuated to release or tension skyline 16.
Drive means, detailed below, will enable carriage 12 to move along cable 16, between pulleys 36 and 38 and to carry a load W along or above slope S. Of course, after skyline tension has been released by rotation of hoist 28 and/or 32, the skidder 22 and/or shovel may move in the same direction transversely to the slope S in order to come in register with unlogged areas of the hill H, so as to enable the carriage 10 to reach new cut trees or logs to be brought down into the valley V.
Carriage frame 12 comprises two transversely spaced, generally rectangular frame sections rigidly interconnected by a plurality of transverse bars one of which is shown at 12a in FIG. 3. Each frame section comprises an upper member 12b, a lower member 12c, an upstream member 12d and a downstream member 12e.
The cable mounting means on the carriage 10 includes an uphill idle pulley 44, carried by an axle 46 mounted across the two frame sections at the corners of frame members 12b and 12d, namely at the uphill carriage end facing towards skidder pulley 36, a downhill idle pulley 50, carried by an axle 52 mounted across the two frame members 12e, and a drive pulley 56, fixedly secured to a drive axle 58 and mounted across the two upper frame members 12b. Downhill idle pulley 50 and drive pulley 56 are located close together at the downhill end of carriage 10. Carriage pulleys 44, 50, 56 must be coplanar, to enable cable 16 to engage at least a portion of the grooved rim of each of these three pulleys.
The relative positions of the drive pulley 56 and of the downhill idle pulley 50 can be changed as illustrated: a first position in FIG. 4, designed for high-gradient or steep slopes S; and a second one, in FIG. 5, designed for low-gradient slopes S.
In the high-gradient pulley configuration of FIG. 4, the drive axle 58 of drive pulley 56 is in a hole or journal 52b located at the corner of frame members 12b and 12e with downhill idle pulley 50 located close to and below drive pulley 56 with its drive axle 52 engaging the journal means indicated by holes 52a made in the two frame members 12e. The straight line joining journal holes 52a, 52b is substantially normal to the straight line joining journal holes 52b to the axle 46 of uphill idle pulley 44. The skyline 16 extends along the uphill half section of the rim of idle pulley 50, along the downhill half section of the rim of drive pulley 56, and tangentially of the lower rim section of uphill idle pulley 44. The cable 16 surrounds more than half the rim of drive pulley 56 for slipless engagement despite the high slope gradient. Also, the line joining the two cable sections issuing from underneath the two idle pulleys 44, 50 is upwardly inclined towards the uphill end of the carriage 10 relative to floor 54 of carriage 10. Thus, the equipment carried inside the carriage on floor 54 is maintained generally upright. In the low gradient position of FIG. 5, pulley 50 takes the former position of drive pulley 56 and the latter takes a low gradient position with its axle 58 engaging the journal means indicated by aligned holes 58a in the two frame members 12b.
Pulley axles 46, 52, and 58 lie substantially on a straight line which extends along the top portion of carriage 10, with drive pulley 56 being located between the other two pulleys proximate idle pulley 50. Cable 16 extends along a quarter section of the lower rim section of pulley 50, along a quarter section of the upper rim section of drive pulley 56 and tangentially of the lower rim section of pulley 44.
It should be understood that switching pulleys 50, 56 from their high gradient to their low gradient position and vice versa, should be a simple operation, which can be done on the field by an unskilled worker, in a short time. Indeed, once the tension on skyline 16 is released, the nuts 62 anchoring pulley axles 52, 58 to carriage frame 12 may be unscrewed, and the axles pulled out whereby the pulleys 50, 56 can be repositioned. In the low gradient position of FIG. 5, the cable 16 has a shorter but still sufficient engagement with the drive pulley 56 for slipless drive and since the line joining the two cable sections issuing from underneath the two pulleys 44, 50 is parallel to floor 54, the equipment carried by the latter is still generally upright.
The cable drive means, shown in FIGS. 4 and 6, comprises an internal combustion engine 64, anchored to carriage floor 54 and driving a hydraulic pump 66 which drives a hydraulic motor 68, on the output shaft 69 of which is keyed the axle 67 of a pinion 70 which meshes and is coplanar with a gear wheel 72 which is fixed to drive pulley 56 by bolts 57. The assembly of pulley 56 and gear wheel 72 is rotatably mounted on a shaft 58 by bearings 73. The resulting unit is removably inserted between frame members 12b and shaft 58, fixed in position by bolts 59.
The position of holes 58a is such that gear wheel 72 meshes with pinion 70 in either position of drive wheel 56. Therefore the radial distance between holes 58a and the axle 67 of pinion 70 is equal to the radial distance between journal 52b and pinion axle 67. Preferably, an automatic safety brake means 74, of any known make, is mounted to output shaft 69, whereby upon stoppage of the feeding of pressurized fluid to hydraulic motor 68, the carriage 10 is automatically immobilized along cable 16 by the engagement of brakes 74 with shaft 69 under the bias of springs. Upon feeding of fluid under pressure to motor 68, the fluid acts against the springs and causes brake release.
Actuation of hydraulic motor 68 is made through a hydraulic circuit including a reservoir 76 connected through line 78 to the intake of pump 66. The output line 80 of pump 66 and the return line 82 to reservoir 76 are connected to a solenoid operated reversing valve 84 which controls the forward and reverse rotation of hydraulic motor 68 through motor lines 86. Brake 74 is suitably connected to lines 86. This circuit is conventional.
The load-grabbing and retaining means is shown in FIG. 4 to consist of a hydraulically operated, reversible hoist 88 and a pulley mounted on an external bracket 91 secured to the uphill end of carriage frame 12, below uphill idle pulley 44. Hoist 88 and pay-out pulley 90 have parallel axles 92, 94. Pull rope 17 is wound onto hoist 88, is trained on the upper uphill quarter rim section of pay-out pulley 90 and then hangs downwardly to be hooked at its bottom end to a load, e.g. tree trunks or wooden logs W. The hydraulic reversible motor of hoist 88 is connected by hydraulic lines 86a of a second electrovalve 84a so as to be controlled in the same way as but distinctly of drive pulley 56. Preferably, an idle roller 96 is mounted on bracket 91 at the outermost, uphill end thereof, and in spaced register with pulley 90, so as to limit the uphill play of rope 17 brought about by swinging action thereof once carriage 10 moves along. Thus, roller 96 prevents disengagement of rope 17 from pulley 90.
The two valves 84, 84a and preferably also the operation of engine 64 are radio-controlled in a known manner. The two idle pulleys 44, 50 support the carriage 10 on skyline 16 by engaging the top of the latter. Drive pulley engages the bottom of skyline 16, is located intermediate the two idle pulleys 44, 50 and its topmost sector is above the straight line joining the lowermost sectors of the two idle pulleys. The frictional engagement of drive pulley 56 is proportional to the tension in skyline 16 which in turn depends not only on the length and consequently weight of skyline 16, but also on the tension exerted by dragline 17 when pulling or carrying a load. Carriage 10 is stabilized against excessive swinging in the vertical plane containing skyline 16 because of the maximum spacing between the uphill idle pulley 44 and drive pulley 56 and because of the uphill position of the dragline pulley 90.
In the system of the invention, the skidder 22 needs not to be permanently manned, contrarily to systems where drag line 17 extends up the hill to the upper anchor point. The operator attaching trees to drag line 17 and radio controlling the carriage mounted hoist 88 and the carriage driving pulley 56 can operate skidder 22 to move it sideways every time he reaches the top of the hill during tree harvesting. The operators gathering the trees at the bottom of the hill look after sideways displacement of power shovel 30. Using a hoist 28, 32 at each mobile anchors provides more flexibility for displacing these anchors.
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A skyline-suspended carriage system for transporting a heavy load slopewisely of a hill, comprising: (a) first and second vertically-offset and horizontally spaced mobile anchor points; (b) hoists, mounted to the first and second anchor points; (c) a single skyline, partially wound around the hoists; (d) an elongated carriage having carriage suspending idle pulleys riding on the skyline and an intermediate driving pulley engaging the bottom of the skyline which is wrapped around the top sector of the driving pulley to obtain slipless engagement; and a load-grabbing and retaining dragline, wound on a hoist in the carriage. One idle pulley and the driving pulley are close together at the downhill end of the carriage while the other idle pulley is substantially spaced from the driving pulley being located at the uphill end of the carriage. This arrangement stabilizes the carriage on the skyline. The positions of the driving pulley and the dowhill idle pulley can be changed to modify the inclination of the carriage relative to the skyline depending on the slope gradient.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to continuously variable transmissions and more specifically to hydraulic control thereof.
2. Background Art
The invention is particularly, although not exclusively, applicable to transmissions which incorporate a ratio varying unit (“variator”) of the toroidal-race rolling traction type to provide the required continuously-variable transmission ratio. Major components of a known variator 10 of the “full toroidal” type are illustrated in FIG. 1 . Here, two input discs 12 , 14 are mounted upon a drive shaft 16 for rotation therewith and have respective part toroidal surfaces 18 , 20 facing toward corresponding part toroidal surfaces 22 , 24 formed upon a central output disc 26 . The output disc is journalled such as to be rotatable independently of the shaft 16 . Drive from an engine or other prime mover, input via the shaft 16 and input discs 12 , 14 , is transferred to the output disc 26 via a set of rollers disposed in the toroidal cavities. A single representative roller 29 is illustrated but typically three such rollers are provided in both cavities. An end load applied across the input discs 12 , 14 by a hydraulic ram 15 provides contact forces between rollers and discs to enable such transfer of drive. Drive is taken from the output disc to further parts of the transmission, typically an epicyclic mixer, as is well known in the art and described e.g. in UK patent application 8429823. Each roller is journalled in a respective carriage 30 which is itself coupled to a hydraulic actuator 32 whereby an adjustable translational force can be applied to the roller/carriage combination. As well as being capable of translational motion the roller/carriage combination is able to rotate about an axis determined by the hydraulic actuator 32 to change the “tilt angle” of the roller and to move the contacts between rollers and discs, thereby varying the variator transmission ratio, as is well known to those skilled in the art.
The illustrated variator is of the type known in the art as “torque control”. The hydraulic actuator 32 exerts a controlled force on the roller/carriage and for equilibrium this must be balanced by the reaction force upon the roller resulting from the torques transmitted between the disc surfaces 18 , 20 , 22 , 24 and the roller 28 . As is well known in the art, the center of the roller is constrained to follow the center circle of the torus defined by the relevant pair of discs. The axis determined by the actuator 32 is angled to the plane of this center circle. This angle is referred to as the “castor angle”. The well known result of this arrangement is that in use each roller automatically moves and precesses to the location and tilt angle required to transmit a torque determined by the biasing force from the actuator 32 .
The biasing force is controlled by means of a hydraulic circuit through which fluid is supplied to the actuators at variable pressure.
It will be appreciated that while the equilibrium position of the rollers is uniquely determined by the balance of the reaction force and the applied biasing force, there is the potential for unwanted oscillatory motion of the roller/carriage combination about this position, with resulting impairment of transmission function. More than one mode of oscillation is possible but in the simplest such mode all rollers oscillate in unison and this oscillatory motion is accompanied by a corresponding flow of fluid in the hydraulic circuit.
Damping of such oscillation can be provided by means of the hydraulic circuit and specifically by suitably restricting or throttling fluid flow to and from the actuators 32 . Such restriction of flow can tend to restrict the motion of the rollers required to effect ratio change, but it has been found that in a lightly damped system these conflicting requirements can be satisfied in a manner which is entirely satisfactory under the majority of operating conditions.
However, particularly stringent requirements are imposed on the transmission during very rapid changes of vehicle speed, particularly in the case of an emergency rapid “brake to rest” e.g. an emergency stop. In order to maintain engine speed and to avoid stalling the engine, rapid ratio change is required of the variator. This is particularly significant in a transmission of the “geared neutral” type in which the variator remains coupled to the vehicles wheels even while the wheels are stationary—that is, in vehicles lacking a clutch or other means to isolate wheels and engine. The high rate of ratio change required during a rapid brake to rest corresponds to a rapid motion of the variator rollers, but if adequate hydraulic flow to accommodate such motion is not available—particularly because such flow is restricted—the rollers can fail to move with sufficient speed, leading e.g. to an engine stall. Within the hydraulic circuit the effect can be a large increase in pressure on one side of the circuit and a large fall in pressure on the other side of the circuit. The result must be a large net biasing force on the roller/carriage combinations and this is reflected in a large variator torque which is the cause of the engine stall.
The applicant's own European patent 1076786 and its US counterpart application Ser. No. 09/678,483 describe a hydraulic variator control circuit in which, by appropriate setting of certain valves, a connection can be made from one side of the actuator 32 to the other, allowing rapid movement of the actuator and its roller in order to effect rapid ratio change. However the switching valves used in this arrangement provide no control of the resulting flow—control of the variator is effectively lost when the valves are set as just mentioned. The valves used to normally control hydraulic pressures applied to the variator are rendered ineffective. This is incompatible with maintenance of stable variator control.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome or alleviate one or more of the above problems associated with known continuously variable transmissions.
In accordance with a first aspect of the present invention, there is a hydraulic circuit for a continuously variable transmission comprising a continuously variable ratio unit (“variator”) which is controllable by means of at least one hydraulic actuator acting on a movable torque transmission element of the variator, the actuator having opposed first and second working chambers and the circuit comprising first and second flow lines both connected to respective actuator working chambers for feeding fluid thereto and therefrom and means for supplying fluid flow through both of the flow lines, variable control valve means being incorporated in both flow lines for generating an adjustable back pressure therein and a further valve being connected between the two flow lines, upstream of the variable control valve means, whereby opening of the further valve enables flow of fluid from one flow line to the other in order to reduce pressure difference between the lines.
By opening the further valve when required the above described problems associated with rapid brake to rest can be prevented.
The use of the variable control valve means in the flow lines is in itself conventional. In known circuits the required damping is in fact largely contributed by the control valve means. Due to its placement upstream of the control valve means, the further valve bypasses the control valve means so that it serves while open to remove or reduce hydraulic damping of actuator motion.
The further valve can serve to relieve both excessive pressure build up in one line and excessively low pressure in the other.
Preferably the further valve has a variable opening. That is, the valve has several intermediate states between maximum opening and closed. Most preferably the valve has a continuously variable opening. Hence the valve can provide a variable degree of relief from one flow line to the other and in this way the opposed requirements for variator damping and (occasional) rapid variator response can be balanced.
Preferably, the further valve is a flow control valve.
It is especially preferred that the circuit is further provided with an electronic control unit (ECU) whereby the opening of the further valve is determined in dependence on measured transmission and/or vehicle operating conditions.
The ECU can establish when operating conditions require opening of the valve, e.g. during rapid brake to rest, and respond accordingly. This may for example be achieved by monitoring engine speed and transmission output speed.
Preferably the ECU is such that after opening the further valve during a rapid change of transmission ratio, it closes the further valve or at least reduces the degree of opening of the valve as the transmission approaches neutral.
It has been found that in this way rapid ratio change may be provided for without an unacceptable degree of oscillation and consequent transmission instability.
BRIEF DESCRIPTION OF THE DRAWINGS
A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
FIG. 1 is a simplified illustration of a known toroidal-race rolling traction type variator which is suitable for control by the hydraulic circuit to be described below;
FIG. 2 is a symbolic illustration of a hydraulic circuit embodying the present invention; and
FIG. 3 is a graph showing how a control current applied to a valve of the FIG. 2 circuit is varied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The hydraulic circuit illustrated in FIG. 2 is suitable for use with a torque control variator of the type described above with reference to FIG. 1 . FIG. 2 shows, by way of illustration, a set of three hydraulic actuators 100 , 100 ′ and 100 ″ (typically in a variator of the above described twin cavity type, six such actuators would be provided—three per cavity—but remaining actuators are omitted for the sake of clarity). Each actuator comprises a piston 102 whose two faces are exposed to control pressure in first and second working chambers 104 , 204 so that the biasing force applied by each actuator is determined by the difference in these control pressures. Each actuator 100 is coupled to a corresponding roller/carriage of the type illustrated in FIG. 1 .
The hydraulic circuit provides a first flow line 106 for supplying hydraulic fluid to the first working chambers 104 and a second flow line 206 for supplying fluid to the second working chambers 204 . The first flow line 106 comprises a supply line 112 and a drain line 114 . A pump 110 draws hydraulic fluid from a sump 111 (and it should be noted that while the diagram shows the symbol for the pump in several places, these are all the same item: the circuit has one sump only) and supplies a pressurized flow of fluid through the supply line 112 to the first working chambers 104 of the actuators 100 . The supply line is branched to connect to all of the working chambers 104 . The drain line however is only directly connected to one of these chambers—chamber 104 ′ of actuator 100 ′, referred to as the first master actuator. Pressure in the supply line 112 —and hence in the actuator working chambers 104 —is controlled by means of a first pressure control valve 116 incorporated in the drain line 114 . The degree of opening of this valve is continuously variable and is determined by an electronic control unit (ECU) 117 . It is again to be understood that while the symbol for the ECU is seen in two places on the diagram for the sake of representational convenience, these symbols both refer to a single such unit. From the downstream side of the pressure control valve 116 , the drain line leads back to the sump 111 from which the hydraulic fluid is recirculated.
The second flow line 206 is similarly formed to the first, comprising a second supply line 212 which supplies pressurized hydraulic fluid from a second pump 210 to the second working chambers 204 and a second drain line 214 leading via a second pressure control valve 216 to the sump 111 . The second drain line 214 is connected to working chamber 204 ″ of a second master actuator 100 ″.
The master actuators 100 ′ and 100 ″ provide limits to the actuator travel, as is known in the art. When the pistons 102 move sufficiently far to the left, piston 102 ′ of the first master actuator 100 ′ covers the mouth of the drain line 114 , preventing a further exhaustion of fluid therethrough and thus preventing further motion of the pistons to the left. The second master actuator 100 ″ limits travel of the pistons to the right in an equivalent manner.
The ECU 117 monitors pressure in both of the flow lines 106 , 206 by means of respective pressure transducers 118 , 218 and adjusts the opening of the pressure control valves to control the biasing force applied by the actuators 100 .
FIG. 2 also shows a valve arrangement 121 of the “higher pressure wins” type having a respective input connected to both of the supply lines 112 , 212 . The arrangement supplies via its output 123 hydraulic fluid from whichever supply line is at higher pressure, to a hydraulic ram (item 15 in FIG. 1 ) for applying the required end load to the variator discs. This feature is in itself well known in the art. Also shown in FIG. 2 are first and second pressure limiting valves 124 , 224 connected respectively to the first and second supply lines 112 , 212 .
Reference has been made above to the need to damp oscillatory motion of the pistons 102 (and the rollers to which they are connected). In the illustrated hydraulic circuit, this damping is largely provided by the pressure control valves 116 , 216 which to some degree restrict fluid flow by virtue of the limited opening they provide therefor. The result is a light damping of piston motion which is compatible, under normal operating conditions, with the speed of motion required of the pistons. This damping effect may in some circuits be augmented by placing restricted “damping orifices” in the two flow lines, as indicated in phantom at 119 , 219 in FIG. 2 . During normal accelerating, braking etc. the hydraulic circuit can provide the rate of fluid flow to/from the actuator working chambers 104 to 204 required to allow the necessary rate of motion of the pistons 102 , not withstanding the hydraulic damping.
However when an event such as a rapid brake to rest creates a need for a very rapid change in variator transmission ratio, the known circuit has proved in some cases to be incapable of providing the required rate of fluid flow. For example, in existing prototype transmissions, the maximum flow from the pump 111 is typically 10 liters/second while rapid braking has been found to require flow to the low pressure sides of the actuators 100 as large as 14 liters/second. On the high pressure side, exhaustion of fluid is limited by the size of the flow path through the relevant pressure control valve (and damping orifice, in certain embodiments).
The problem is overcome in the illustrated circuit by means of a valve, in this embodiment a flow control valve 125 , which is connected between the first and second flow lines 106 , 206 , upstream of the pressure control valves 116 , 216 . In fact in the illustrated embodiment the flow control valve 125 is connected across the drain lines 114 , 214 . That is, the valve 125 is downstream of the actuator working chambers 104 , 204 . The flow control valve 125 is normally closed and so does not significantly affect the operation of the hydraulic circuit or the variator as a whole under normal operating conditions. The valve is controlled by the ECU to open when, as in a rapid brake to rest, there is a requirement for particularly rapid ratio change. When opened, the flow control valve 125 provides a route for fluid to flow from one flow line 106 , 206 to the other, bypassing the pressure control valves 116 , 216 . Hence a greater rate of flow of fluid out of the high pressure side of each actuator 100 is made possible, along with a greater rate of flow into the low pressure sides. The effect is that, with the damping effect from the pressure control valves 116 , 216 greatly reduced, the variator can very rapidly change ratio. Opening of the valve reduces pressure difference across the two flow lines 106 , 206 which resists rapid ratio change.
The control of the flow control valve 125 will now be explained with reference to FIG. 3 .
The ECU receives signals representative of several quantities relating to operation of the transmission and of the vehicle as a whole. These include for example brake and throttle pedal positions, engine speed, transmission speed and so on.
In response, the ECU controls, inter alia, the pressure control valves 116 , 216 and the flow control valve 125 . The degree of opening of the flow control valve 125 is determined by a control current applied thereto, and the size of this current is set by the ECU with reference to a look-up table which is graphically represented in FIG. 3 . In this particular embodiment, the control current is set in dependence upon two variables:
i. the transmission ratio, calculated by the ECU based on the engine speed and the transmission output speed; and
ii. the rate of vehicle acceleration, calculated as the first differential of the transmission output speed.
It must be understood in order to comprehend FIG. 3 that the flow control valve 125 of the present embodiment of the invention is of the type which is fully open when the control current is zero and which requires a current—in this case two amps—to be fully closed. This means that a current must be applied to the valve constantly during normal operation of the transmission. In production versions of the transmission, for the sake of energy efficiency, a valve operating in the opposite sense is likely to be used—ie. a valve which is closed when the control current is zero.
It will be noted from the graph that the ratio of the transmission under consideration can reach zero. This is done without use of a clutch or torque converter to disconnect the engine from the transmission output. Such “geared neutral” operation is well known to those skilled in the art and so will not be explained in detail herein. A known transmission using an epicyclic mixing gear to achieve geared neutral is disclosed for example in GB8429823. It should also be understood that the transmission under consideration has at least two “regimes”—high regime and low regime—the relationship between the ratio provided by the variator and the ratio provided by the transmission as a whole being different in the two regimes. Again, multi-regime transmissions are well known in the art and the necessary gearing arrangements will not be described in detail herein. Low regime provides a low range of ratios including geared neutral. High regime provides a higher range of ratios. A transition from one regime to the other takes place by shifting of regime clutches at a predetermined “synchronous” ratio at which opposite sides of the clutches are revolving at identical speeds.
Turning now to FIG. 3 , it can be seen that vehicle acceleration rates below a chosen threshold—in the region indicated at 300 —produce no opening of the flow control valve 125 . This corresponds to normal driving with moderate rates of ratio change, the flows produced in the variator circuit being accommodated by the pressure control valves 116 , 216 . Also at high transmission ratios, in the region 302 , the flow control valve 125 is not opened. At these high ratios the rate measurement required of the variator rollers, even upon rapid vehicle acceleration, is relatively low. Hence the large level plateau 300 , 302 represents “normal” operation, with a two amp current applied to the flow control valve 125 to maintain it in its closed configuration. This is always the case below a certain vehicle acceleration of roughly 15 km/hr/s and also above a certain transmission ratio of roughly 1. The remainder of the graph corresponds to operating conditions in which the flow control valve 125 is at least partially opened in response to rapid change in vehicle speed at relatively low transmission ratio.
Under such conditions, two conflicting requirements must be reconciled. To achieve rapid ratio change, a low level of hydraulic damping of the piston motion is required. As has been explained above, opening of the flow control valve 125 , bypassing the pressure control valves 116 , 216 , achieves this. However there remains the requirement that oscillatory motion of the pistons 102 (and hence the variator rollers) must be kept within acceptable limits.
To appreciate how these requirements are both satisfied, consider what happens as a fast moving vehicle is braked to rest. The transmission ratio is initially high but must fall to zero. Initially the flow control valve is closed but as the transmission ratio falls below about 1, the ramped surface 304 indicates that the valve is progressively opened. Regime change, from high to low during braking, takes place at a ratio of roughly 0.6, in low regime the variator rollers must move faster, for a given vehicle deceleration rate, than in high regime. Hence in a region 306 the valve 125 is fully open. The variator rollers and the pistons 102 must move rapidly in this phase but this un-damped rapid motion is necessarily brief. As the vehicle approaches rest (zero transmission ratio) the requirements change. Stable variator operation in this final phase requires hydraulic damping, and the rates of flow and pressures in the hydraulic circuit are reduced (to understand why, consider that the transmission is approaching the geared neutral state in which no torque is transmitted, corresponding to zero applied force from the hydraulic actuators). Hence as the vehicle approaches rest the flow control valve 125 is rapidly closed, as represented by upwardly turned lip 308 .
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A hydraulic circuit for a continuously variable transmission having a continuously variable ratio unit that is controlled by at least one hydraulic actuator acting on a movable torque transmission element. The actuator has opposed first and second working chambers. The circuit includes first and second flow lines that are connected to two respective actuator working chambers. The lines feed fluid thereto and therefrom A pressurized supply of fluid urges fluid flow through the flow lines. A variable control valve is incorporated in both flow lines. Each valve generates an adjustable back pressure therein. A further valve is connected between the two flow lines. The further valve has a variable opening and is located upstream of the variable control valve. Opening of the further valve enables flow fluid from one flow line to the other to reduce pressure difference between the lines.
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This is a continuation of application Ser. No. 001,692, filed Jan. 9, 1987, now U.S. Pat. No. 4,778,685, issued Oct. 18, 1988, which is, in turn, a division of application Ser. No. 611,671, filed May 18, 1984, now U.S. Pat. No. 4,679,496, issued July 14, 1987.
BACKGROUND OF THE INVENTION
The present invention relates to the manufacture of laminated products having many layers, and, more particularly, to the manufacture of laminated food products, such as candy, which are formed by the layering of a smooth nonabsorbent material and a soft flowable material.
For many years, candy bars have been manufactured which have a crisp texture together with a strong flavor component associated with a soft material. This combination of texture and taste has been achieved by producing a laminate which contains many thin layers of a brittle candy separated by thin layers of the soft flavor material.
These candy bars are conventionally made by a labor intensive process that produces consistent results. In the prior art process, a hot solution of corn syrup and sugar is dropped on a circular chilled table. A pair of scrapers work the solution by drawing it from opposite outer edges of the table toward the center, the table turning about 1/8 turn between successive scraper operations. As the solution cools, it turns into a soft pliable taffy. Color and flavor ingredients, in liquid form, may be added to the taffy by pouring it into a depression formed in the taffy mass. The taffy mass is manually folded to cover and close the depression. The mass is then manually lifted onto the hooks of a taffy puller. The puller works the taffy, aerating it to reduce its density.
The aerated taffy is transferred from the puller to a conveyor and is fed between rollers to form a thin sheet. A layer, for example, of hot peanut butter is applied to the sheet and the sheet is severed at predetermined levels. Each section of sheet is rolled into a log weighing about 80 lbs. The log is folded in half, fed between rollers and rolled out into a sheet once more. This sheet is again rolled into a log which is manually wrapped in a sheet of taffy to keep peanut butter from squeezing out the ends and to provide and insure that the product pieces have an outer sheet of candy with no exposed peanut butter.
The log is manually placed in one of a number of spinning machines that feed a conveyor. The spinning machines have several long rotating cones provided with traction knobs and are positioned on axes that coverage toward the output end. The cones are spaced to receive the log and are rotated to draw the log toward the output end and thus stretch the log into a rope about 1/5 its original diameter (from about 5 inches diameter to about 1 inch diameter). The ends of the rope are manually fed onto a conveyor which carries a number of ropes each formed by a separate spinner. The ropes are divided into product sized bars and enrobed with chocolate.
The sheet of taffy in which the log is wrapped forms a taffy wall at each end of the log. As these end portions are stretched out to form the rope, they produce rope sections containing unlaminated taffy. This results in undesirable hard spots in the candy bars.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method and apparatus for continuously producing uniform products that are composed of alternate layers of different materials.
It is a further object to provide a method and apparatus which has a particular application in the manufacture of laminated candy products made of alternating layers of hard and soft materials.
It is still a further object to provide a method and apparatus which eliminates the disadvantages of known methods of making laminated candy products.
These and other objects of the present invention are achieved by a method for producing a laminated sheet product comprising the steps of continuously forming a semifluid sheet of a first material on a moving conveyor, continuously depositing a second material onto the sheet of first material to form a layered sheet of the first and second materials, continuously rolling the layered sheet from the edges thereof inwardly to form a double roll extending longitudinally along the conveyor and flattening the roll to form a laminated sheet. In order to produce individual commercial product sized pieces, the laminated sheet is then divided into longitudinally extending strips and the strips are then cut transversely into individual pieces.
In accordance with the above described method, the objects of the invention are achieved by an apparatus for producing a laminated sheet product having alternating thin layers of a semifluid first material and a semifluid second material comprising longitudinally extending conveyor means, means for continuously forming a semifluid sheet of the first material on the conveyor means, means for continuously depositing the second material on the sheet to form a layered sheet of first and second materials, means for continuously rolling the sheet from the edges thereof inwardly to form a double roll extending longitudinally along the conveyor means and means for flattening the roll into a laminated sheet product.
Other objects, features and advantages of the present invention will be apparent from a reading of the detailed description which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention have been chosen for purposes of illustration and description, and are shown in the accompanying drawings forming a part of the specification, wherein:
FIGS. 1A to 1E provide a top plan view of apparatus according to the present invention when laid out end to end in sequential order;
FIGS. 2A to 2E provide a front elevational view of the apparatus shown in FIGS. 1A to 1E when laid out end to end in sequential order;
FIGS. 3A to 3E provide a top plan view of a second embodiment of apparatus according to the present invention when laid out end to end;
FIGS. 4A to 4E provide a front elevational view of the apparatus shown in FIGS. 3A to 3E when laid out end to end;
FIG. 5 is a sectional view of the product on the conveyor taken along lines 5--5 of FIG. 1A;
FIG. 6 is a sectional view of the product taken along line 6--6 of FIG. 1C;
FIG. 7 is a sectional view of the product taken along line 7--7 of FIG. 1C;
FIG. 8 is a sectional view of the product taken along line 8--8 of FIG. 1C;
FIG. 9 is a sectional view of the product taken along line 9--9 of FIG. 1C;
FIG. 10 is a sectional view of the product taken along line 10--10 of FIG. 3A;
FIG. 11 is a sectional view of the product taken along line 11--11 of FIG. 3A;
FIG. 12 is a sectional view of the product taken along line 12--12 of FIG. 3A;
FIG. 13 is a sectional view of the product taken along line 13--13 of FIG. 3C;
FIG. 14 is a sectional view of the product taken along line 14--14 of FIG. 3D;
FIG. 15 is a sectional view of the product taken along line 15--15 of FIG. 3D;
FIG. 16 is a top plan view of a modification usable in place of a laterally oscillating chute or conveyor; and
FIG. 17 is a front elevational view of the apparatus of FIG. 16.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, there is shown in FIGS. 1A--1E and 2A--2E one embodiment of apparatus according to the present invention in which a cooking and aerating unit 10 continuously produces a stream of hot aerated solution of corn syrup and sugar, discharging the stream through a nozzle 11 onto a steel band conveyor 12. The unit 10 may be one of the type manufactured by the Otto Hansel company of Germany and sold under the trade name SUCROLINER.
The solution exiting from the nozzle 11 is at about 258° F. and is in a very liquid state. A water cooling unit 14 is provided below the upper run of the conveyor 12 to cool the solution to a working temperature between 160° F. and 200° F., at which temperature the solution is in a plastic state. The cooling unit 14 sprays water on the bottom surface of the upper run of the conveyor band. The temperature of the spray water varies from about 160° F. near the input end of the conveyor 12 where the solution is hottest to about 120° F. near its output end.
The stream of solution discharged from the nozzle 11 is immediately spread across the conveyor 12 by a spreader 15 to form a sheet of candy. Ground candy scrap, commonly referred to as "rework", is sprinkled onto the sheet from a vibratory feeder 16 and melts into the hot sheet.
A pair of plow blocks 17 (which are suspended from an overhead framework not shown) engage the edges of the candy sheet and fold the edges over onto the center as shown in cross section in FIG. 5. The plow blocks 17 may be rectangular blocks of plastic or metal which are formed with a concave surface 19 for engaging and folding over the candy sheet.
The folded sheet exiting from the first set of plow blocks 17 is rolled down and stretched by a cleated roller 20. The sheet exiting from the roller 20 is again folded by a pair of plow blocks 21 and then rolled and stretched by a second cleated roller 22. The narrow thick sheet or rope of candy leaving the roller 22 is then turned over twice, as shown in FIGS. 1B and 2B, by single plows 24 and 25 spaced further along the conveyor 12.
The folding and turning of the candy sheet by the plow blocks 17, 21, 24 and 25 allows the candy to cool evenly and prevents excessive cooling of one surface which would result in hardening or "skinning over" of the surface.
Referring now to FIGS. 1C and 2C, at the end of conveyor 12, the rope of candy is transferred onto an oscillating chute 26, and from that chute onto a second conveyor 27 which is traveling at a slower rate than the conveyor 12. The chute 26 oscillates about a vertical axis centrally placed at the input end of the chute. The chute 26 narrows toward its output end and is provided with side walls 29 to direct the flow of the candy rope. The chute 26 is mounted on a vertical shaft 30 which is oscillated about its axis by a motor 31 through a crank 32 on the shaft of the motor, an arm 34 on the shaft 30 and a link 35 interconnecting the crank 32 and the arm 34.
The oscillating motion of the chute 26 causes the candy rope to be laid down in a sinuous pattern on the slower moving conveyor 27. A pair of guide plates 36 (supported by an overhead framework not shown) confine the folds of the candy rope allowing them to build up in front of a smooth sheeting roll 37. The sheet roll 37, operating against a backing roll 39 beneath the conveyor belt, rolls the accumulated candy mass into a thin candy sheet. This sheet is operated upon by a scoring roll 40 which is formed with two sets of helical ridges (a lefthand set and a right hand set) extending outwardly from the center of the roll. The roll 40 turns at the same speed that the candy sheet is moving and impresses into the candy sheet a "herring-bone" pattern comprising a series of "V" shaped grooves 41 pointing in the direction the sheet is traveling, as shown in FIG. 1C.
Immediately after the roll 40, hot liquefied peanut butter, for example, may be dispensed onto the candy sheet. The peanut butter is pumped from a unit 42 to a pipe 44 that extends across the conveyor 27 and is provided with a number of dispensing nozzles spread across the candy sheet. The peanut butter is spread with a spreader 45 across the candy sheet and into the grooves 41, as shown in cross section in FIG. 6. The sheet is then rolled from each edge toward the center of the sheet by a pair of sidewinder units 46, each of which contain a serrated roller 47. The units 46 are positioned at each side of the conveyor 27 and the rollers 47 extend over the conveyor at an inward angle from the direction of conveyor travel.
The rollers 47 engage and lift the edges of the candy sheet and roll them toward the center to form a double jelly roll configuration as is shown in cross section in FIG. 7. The grooves 41, because of their orientation, aid in the rolling process. They also act as receptacles to hold the peanut butter within the double roll configuration and thus prevent the peanut butter from squeezing out as the roll is formed.
The double rolled sheet is rolled down by a cleated roller 49 to form a laminated thick sheet as shown in cross section in FIG. 8. This sheet is folded in half by a plow block 50 to form a laminated rope as shown in cross section in FIG. 9. This rope is rolled out into a relatively thick laminate by a cleated roller 51 as shown in FIGS. 1D and 2D. The thick sheet moves from the end of the conveyor 27 through a swing laminator 52 onto a conveyor 54. The laminator 52 includes a substantially vertical plate 55 positioned under the outlet end of the conveyor 27. The plate 55 is pivoted at its upper end about a horizontal shaft 56 and is oscillated by means not shown, to move in an arc as shown by the arrows and thereby repeatedly fold the candy sheet back on itself, placing one layer of laminate upon another. The number of these layers in the sheet produced by the laminator 52 is controlled by the rate of oscillation of the plate 55 and the speed of the conveyor 54 relative to that of the conveyor 27. However, typically three layers of laminate are combined in this manner so that the number of layers of peanut butter and candy are tripled. A pair of side wall guide plates 57 are provided to keep the layers in alignment, one with another.
The laminated sheet is rolled down in three successive stages by cleated rollers 59, 60 and 61. The rolled out thin sheet is transferred to a conveyor 62 and is rolled out further by a sheeting roll 64. This thin sheet is then rolled inwardly from both edges by a second pair of sidewinders 65 to produce another double jelly roll configuration and once again multiply the number of layers of peanut butter and candy in the final product. Each time the number of layers are increased and the sheet is rolled out again, the individual layers become thinner, giving the product a more delicate nature.
At the end of the conveyor 62, as shown in FIGS. 1E and 2E, the double rolled sheet is rolled down by a cleated roller 66 and the rolled down sheet is twisted 180 degrees and fed onto a conveyor 67 disposed beneath the conveyor 62. This twisting action can be accomplished by plow blocks, for example, similar to the plow blocks 24 and 25 shown in FIGS. 1B and 2B. The sheet is then rolled out in three successive stages by cleated rollers 69, 70 and 71. The reason for twisting the sheet is that at least part of the bottom surface of the candy may have been continuously against the conveyor and may not have been directly subjected to the stretching and working action of the cleated rollers. Therefore the bottom candy layer of the laminate is thicker and denser than the other layers at the point of the 180 degree twist. The rollers 69, 70 and 71 stretch and thin this layer to make the laminate more uniform throughout its cross section.
The laminate is then transferred to a conveyor 72 and is rolled to its final thickness by sheeting rolls 74 and 75. The sheet is longitudinally grooved by a pre-form roller 76 to facilitate cutting. The preformed sheet moves off the conveyor 72 and between a slitter roll 77 and a back up roll 79. The preformed sheet is longitudinally cut by the slitter roll 77 which has a plurality of thin cutting blades 80. To insure complete severing of the sheet, the back up roll 79 may be provided with slits to receive the tips of the cutting blades. The separated product strips are given their final cross-sectional shape by a shaping roll 81. The product strips may then be cut into product sized lengths and enrobed or encapsulated with chocolate.
Referring now to FIGS. 3A-3E and 4A-4E, there is shown another embodiment of apparatus according to the present invention which includes the same cooking and aerating unit 10, steel band conveyor 12, water cooling unit 14, spreader 15 and vibratory rework feeder 16.
In this embodiment, the peanut butter is preferably deposited on the candy sheet immediately after the rework is added by application pipe 82. The pipe 82 extends from a pressurized source of peanut butter across the conveyor 12. The pipe 82 is provided with a nozzle 84 positioned a short distance from one edge of the candy sheet, and a nozzle 85 positioned further toward the center of the sheet. The two nozzles deposit parallel spaced streams of peanut butter 86, 87 upon the sheet.
A plow block 89 lifts the edge of the candy sheet and rolls it over the first peanut butter stream 86 as shown in cross section in FIG. 10. A second plow block 90 or an extension of the first lifts the enrobed stream 86 and rolls it over the second peanut butter stream 87 as shown in cross section in FIG. 11. A third plow block 91 on the opposite side of the conveyor lifts the other edge of the sheet and folds it over upon the two enrobed streams as shown in FIG. 12.
The folded sheet is rolled down by a cleated roll 92 to seal the top two candy layers together and thereby encapsulate the peanut butter within a candy coating. The sealed rope of candy and peanut butter is turned over twice as shown in FIGS. 3B and 4B by single plows 24 and 25 spaced along the conveyor 12. The folding and turning of the candy allows the candy to cool evenly and prevents excessive cooling of one surface which would result in hardening or "skinning over" of the surface.
After being rolled down and turned over twice, the product rope consists of two layers of peanut butter separated and surrounded by candy as shown in cross section in FIG. 13. In this embodiment the product rope is transferred from the conveyor 12 to the conveyor 27 by a laterally pivoting conveyor 94.
The conveyor 94 is supported at its input end by a yoke 95 having a shaft 96 that is journalled in a block 97 which is supported by suitable framework 99. The output end of the conveyor 94 is supported by a wheel 100 oriented transversely of the conveyor and riding on a track 101 which is suitably supported. The output end of the conveyor is oscillated transversely by a motor 102, a crank 104 mounted on the motor shaft, an arm 105 secured to the conveyor 94, and a link 106 connecting the crank 104 to the arm 105.
The transverse oscillation of the conveyor 94 causes the layered rope to be laid down in a sinuous pattern on the slower moving conveyor 27 between the guide plates 36. The folds of the layered rope pile up against the smooth sheeting roll 37 and these folds are pressed together between the sheeting roll 37 and a back up roll 39 to produce a candy sheet having 2 to 4 times as many layers as the layered rope.
The laminated sheet then flows directly to the two sidewinder units 46 where the sheet is rolled from each edge toward the center to produce the double jelly roll configuration and again multiply the number of laminations in the final product. Radiant heaters 47 may be employed as shown to insure that the sheet is sufficiently pliable.
Referring now to FIGS. 3D nd 4D, the double rolled sheet is rolled down by a cleated roll 49 and is folded over from each edge by plow blocks 107 and 109 to an on-edge configuration shown in cross section in FIG. 14. A third plow block 110 lays the folded sheet on its side and the sheet now has double the number of laminations as the sheet rolled out by the cleated roll 49.
The sheet is then fed to another cleated roller 51. The wider rolled out sheet exiting from roller 51 flows into the laminator 52 where it is folded back on itself in a number of layers to further multiply the laminae in the product. sheet, as explained above with respect to FIGS. 1D and 2D.
In this embodiment, on-edge belt conveyors 111 and 112 are used as guides to keep the layers in alignment with one another. The laminated sheet is then rolled down in stages by the cleated rollers 59, 60 and 61, and is then transferred onto conveyor 72 where it is rolled out by a sheeting roll 114. A pair of side guides 115 extend from the roller 61 to the roll 114 to control the width of the sheet supplied to the roll 114. The roll 114 is provided with a pair of ridges 116 to insure that the sheet exiting from the roll 114 is of uniform width. The conveyor 72 is driven at a somewhat faster rate than the roller 61 to stretch out and thin the laminated candy sheet.
At the end of the conveyor 72, as shown in FIGS. 3E and 4E, the laminated candy sheet moves under the preform roller 76 and between the slitter roll 77 having blades 80 and the slitted back up roll 79. The product strips exiting the slitter roll 77 are carried by a conveyor 117 under the shaping roll 81 and then transferred to a diverging conveyor 119 which may include, for example, a plurality of angled guide or guides of increasing width. The product strips leaving the diverging conveyor 119 are laterally spaced from each other and are transferred to a conveyor 125 where they are cut into product size lengths by a cutter, for example, a rotary cutter 126. The product pieces are spaced longitudinally by transferring them to a faster moving conveyor 127 for chocolate encapsulation.
In FIGS. 16 and 17 there is disclosed an arrangement which could be used in place of the oscillating chute 26 of the first embodiment, shown in FIGS. 1C and 2C, or in place of the pivoted conveyor 94 of the second embodiment, shown in FIGS. 3C and 4C. In the arrangement of FIGS. 16 and 17, diverging vertical guide walls 129 are provided prior to the sheeting roll 37 and the speed of the conveyor 27 is adjusted with respect to that of conveyor 12 to create a piling up of candy mass in front of the sheeting roll 37, much as shown in FIGS. 1C and 3C.
In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive means.
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A method and apparatus for producing laminated products, such as candy, is disclosed. The method includes the steps of continuously forming a semifluid sheet of a first material on a longitudinally extending conveyor, depositing a semifluid second material on the sheet of the first material, continuously rolling the sheet from the edges thereof inwardly to form a double roll extending longitudinally along the conveyor, and flattening the roll into a laminated sheet product. The method further includes the steps of forming the sheet into a "rope" of substantially smaller width than the sheet by folding the sheet over itself from the edges of the sheet and allowing the rope to move transversely across a slower moving conveyor so that the rope bunches up on the conveyor. The rope is then flattened by a roller. The method also includes the step of causing the sheet to longitudinally fold over itself so as to form laminations. Additionally, the method includes the steps of dividing the laminated sheet product into longitudinally extending strips and transversely dividing the strips into individual product pieces. Apparatus for achieving the method is also disclosed.
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BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to a ceramic tile having improved abrasion resistance and a method for applying an abrasion resistant layer. Specifically, it relates to ceramic insulation tiles used in high-temperature aircraft applications to protect metallic structure from hot engine exhaust.
2. Background Art
Ceramic insulation tiles are used in aircraft applications to protect the aircraft metallic structure from high temperature engine exhaust. Current insulation tiles provide adequate protection from high temperatures, but not from the abrasion caused by high velocity engine exhaust gases and associated erodents. Because high temperature insulation tile is composed of a porous lightweight ceramic, however, abrasion is particularly damaging to the physical integrity of the ceramic tile.
For example, engine exhaust gases such as CO 2 , O 2 , CO, and unburned fuel at high flow rates can abrade and erode insulation tile. Further, abrasion can arise from airborne particulate matter related to aircraft operation such as sand, dirt, soot, engine coatings, and turbine blade particles. Therefore a means of improving the abrasion resistance of such insulation tiles to extend the life of such tiles and reduce the cost of operation of the related aircraft is required.
Current methods of increasing the abrasion resistance of insulation tiles are costly and labor intensive. For example, one method is the chemical vapor deposition of SiC onto such tiles. This approach is costly and has limited improvements in abrasion resistance. Another approach is to spray a glass frit on the tile in multiple steps. This method requires extensive training of production personnel, is costly and very labor intensive. Further, the results of this process may not be highly reproducible because of the many manually controlled steps involved in the process.
Thus, one object of the invention is to provide a ceramic insulation tile that is resistant to abrasion from the types of gas flow and erodents present in high temperature aircraft operation.
Another object of the invention is to provide an abrasion resistant ceramic insulation tile that is low in cost and can be made with a process that is not labor intensive.
Another object of the invention is to provide a process to make an abrasion resistant ceramic insulation tile that is uncomplicated and, therefore, highly reproducible. This object will also reduce the cost of the resulting tile.
A further object of the invention is to provide an abrasion resistant ceramic insulation tile that is lightweight, which object is a mission critical parameter on all modern aircraft for performance and economy of operation.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided an abrasion resistant ceramic insulation tile. The insulation tile is provided with a porous ceramic material having a surface. The insulation tile is further provided with a preceramic polymer which is permeated through the surface. The preceramic polymer forms an integral ceramic matrix with the porous ceramic material upon pyrolyzation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a pictorial diagram of the infiltration, curing and pyrolyzing steps of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The method used to create an abrasion resistant ceramic insulation tile is to densify the tile surface. This process increases the strength and hardness of the tile surface and, therefore, the abrasion resistance of the tile.
As shown in FIG. 1, a polymeric precursor 100, which is also referred to as a preceramic resin or preceramic polymer, is poured into a container 105 up to a predetermined depth H. A ceramic insulation tile 110 is then placed in the container to allow the polymeric precursor 100 to soak into the tile to a depth H. The time required for this absorption to occur varies with the composition of the tile 110 and the polymeric precursor 100 as will be explained later.
After this soak step, the tile 110 with the absorbed polymeric precursor 100 is processed in accordance with the process steps specified by the manufacturer of the polymeric precursor to transform the absorbed precursor into a ceramic. For example, the absorbed tile 120 is cured at a low temperature for several hours in air. This step is typically followed by a high temperature pyrolyzing step in an inert atmosphere 125 (for non-oxide ceramic precursors), such as high purity argon or nitrogen. This step is usually performed in a standard furnace 130, at an elevated temperature.
The selection of the compositions for the tile 110 and preceramic polymer 100 are interdependent, and also dependent on the abrasion resistant properties desired to be achieved. For example, the material selected for the tile 110 must be porous enough to allow absorbtion of the preceramic polymer 100 that is selected while retaining the heat resistant properties for which the tile was selected for the operational environment, e.g., aircraft exhausts. Although a specific preferred porosity depends on the viscosity of the preceramic polymer 100 selected, ceramic porosities in the range of 50-95 percent open porosity will allow the extent of densification required to achieve the objects of the invention.
The preceramic polymer 100 selected must have a viscosity low enough to penetrate the porous tile 110 to a desired depth, which controls the properties to be achieved. The viscosity must not be too low, however, because this will cause the preceramic polymer 100 to be absorbed in an uncontrolled manner into the tile 110. For example, if the viscosity is too low, the preceramic polymer 100 will densify the entire tile 110 resulting a tile that is far too heavy for the intended application. If the viscosity is too high, the preceramic polymer 100 will not absorb deep enough into the tile 110 to create a dense ceramic layer having the desired properties.
Thus, it is an aspect of the invention to select the preceramic polymer 100 to have a viscosity that will be absorbed into a selected tile 110 to a depth that will increase the abrasion resistance of the tile to a desired degree. In addition, it is an aspect of the invention to select the preceramic polymer 100 to have a post-pyrolysis ceramic strength and toughness adequate to achieve the desired abrasion resistance. The type of preceramic polymer 100 and the depth to which it is absorbed in the tile 110 will determine the increase in such abrasion-related properties such as erosion resistance or impact resistance. Although a preferred viscosity is dependent on a specific porosity of tile 110, viscosities in the range of 1 to 400 centipoise will provide the extent of densification required to achieve the objects of the invention.
The depth that the preceramic polymer 100 will penetrate the tile 110 is also dependent on the interfacial forces that exist between the two materials. These forces determine the degree to which the preceramic polymer 100 will wet the tile 110 and, consequently, the depth to which the polymer will penetrate the tile.
Another aspect of the invention is that the method produces a densification of the tile 110 that is reproducible in production quantities. Initially, the uncomplicated nature of the process of the invention contributes substantially to this object. In addition, the viscosity of the preceramic polymer 100 and porosity of the tile 110 may be selected such that the polymer will be absorbed only up to the height H to which the tile is immersed in the polymer during the soak step described previously. Selection of the materials in this manner will ensure that the depth of densificaton, and resulting strength increases, will be reproducible. Of course, selection of the preceramic polymer 100 in this manner may not be possible if the preferred viscosity will not allow transformation into a ceramic with the desired strength and toughness properties.
The following working example demonstrates how the objects of the invention are achieved. In this embodiment, the preferred preceramic polymer 100 was formed with Blackglas™ 489D resin sold by the Allied Signal Corporation, which pyrolyzes to form a silicon-oxycarbide ceramic. This resin was mixed with 0.05 percent by weight of Blackglas 489B catalyst to form the preceramic polymer 100. This mixture was poured into a flat-bottomed container to an approximate depth of 0.10 inch. The tile used was an alumino-silicate ceramic insulation tile made by McDonnell Douglas Technologies Inc. that had a density of 16 lb/ft 3 , which samples were 1 inch thick. The tile was placed in the container with the Blackglas mixture and allowed to soak for 15 seconds at room temperature, after which time the Blackglas mixture had absorbed into the tile to the depth of the mixture, i.e., 0.10 inch.
The tile was then removed from the soak container and the manufacturer's directions for curing were followed. Specifically, the absorbed tile was cured at 130 degrees Fahrenheit for three hours in air. The cured tile was then pyrolyzed in a (high purity) argon atmosphere at 1,500 degrees Fahrenheit for 3 hours to complete the surface densification process. The areal weight gain for this densification method was typically 0.035 lb/ft 3 .
The abrasion resistance of both the untreated and densified tiles was measured using a Taber abrader device. This test uses an abrasive wheel that runs a circular track around a 4 inch by 4 inch sample surface. Following the abrasion, the depth of wear and weight loss is measured to quantify the abrasion resistance. The Taber abrasion tests were performed for 100 rotations at 70 rpm using a CS-17 wheel and a mass of 500 grams. Shore hardness A tests were also performed on both tiles to evaluate their hardness.
Table 1 shows the results of testing on both the untreated and densified tiles. The hardness of the tile was increased from 62 in the untreated state to 90 after the densification with Blackglas. The 100 cycle weight loss for the densified tile was greater than the untreated tile because of the higher density of the densified tile. The wear depth of the densified tile was 3.57 thousands of an inch ("mils"), which was considerably less than the wear depth of the untreated tile which was 5.86 mils. This latter test represents a significant improvement in abrasion resistance of approximately 40 percent.
TABLE 1______________________________________ Hardness 100-Cycle Wear DepthType (Shore A) Weight Loss (g) (mils)______________________________________Bare 62* 1.32* 5.86Densified 90* 2.81* 3.57______________________________________ *average of two tests
The method of the invention can be used with a range of porous oxide and non-oxide ceramics, such as those used for high temperature insulation tiles. Such porous ceramics include those made from alumina, alumina silicate, silicon carbide (a non-oxide ceramic), mullite and zirconia. The porosity may be created and controlled by a variety of processes, including chemical vapor deposition, a slurry dip process, powder processing or the use of a blowing agent to foam these materials.
A range of polymeric precursors may be used with these porous ceramics to produce an abrasion resistant ceramic, including Tonen "PHPS-1" and "PHPS-2" (by Tonen Corporation of Tokyo, Japan), polyvinylsilane or "PVS" (by Union Carbide Corporation of Danbury, Conn.), or SwRI silicon nitrate (by Southwest Research Institute of San Antonio, Tex.) or Starfire silicon carbide (by Starfire Corporation of Watervliet, N.Y. ). In addition, any of the spirosiloxane oligomers and polymers that are precursors to a silicon carboxide ceramic or "black glass" (e.g. "Blackglas" by Allied-Signal) may also be used. In each case, the curing times and temperatures specified by the manufacturers are followed to densify the surface of the porous ceramic tile.
A range of depths H of the polymeric precursor to absorb into the porous ceramic tile can be used, depending on the desired properties to be achieved. Although it may be desirable to increase the depth H to increase the strength of the densified tile, this effect must be balanced against the increased weight due to the densified ceramic which may be undesirable for the intended application. In general, densification depths in the range of 0.050 to 0.500 inches provided reasonable increases in abrasion resistance with acceptable weight increases.
In another embodiment of the method, the following steps of the invention are repeated to increase the density of the infiltrated ceramic: infiltrating the porous ceramic with a polymeric precursor, curing the infiltrated polymeric precursor, and pyrolyzing the infiltrated polymeric precursor to form an infiltrated ceramic. The increased density of infiltrated ceramic results in increased strength and hardness.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
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In accordance with the present invention, there is provided an abrasion resistant ceramic insulation tile. The insulation tile is provided with a porous ceramic material having a surface. The insulation tile is further provided with a preceramic polymer which is permeated through the surface. The preceramic polymer forms an integral ceramic matrix with the porous ceramic material upon pyrolyzation.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to lighting fixtures and, more specifically, to a light fixture mounted in a window to shine out in order to obstruct a view inside, while providing those inside a lit view outside.
2. The Prior Art
A number of trends have come together to make many people more concerned about their privacy. One trend is increasing wealth, which increases the desire for privacy. Another is that as people move around the country more often, they less often know their neighbors very well. This all comes together with people more and more interested in keeping others from looking through their windows into the house.
Traditionally, privacy in a house has been implemented through shutters, followed by curtains, and more recently, blinds and other window treatments. One disadvantage of these approaches to privacy is that the measures that they take to keep people from looking through windows from the outside typically makes it more difficult to see through the windows from the inside.
BRIEF SUMMARY OF THE INVENTION
A lighting system includes a lighting unit and a mounting structure. Light from the lighting unit is mounted adjacent to a window to shine outward, obstructing a view of the inside of a space such as a house, commercial space, car, boat, etc., while allowing those inside a clear, lighted view of the outside. The lighting unit may be powered by electrical wiring, battery, or solar. Light is preferably adjustable in various directions. The lighting system provides additional security and privacy.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing a front view of an adjustable light fixture mounted in a window, in accordance with one embodiment of the present invention;
FIG. 2 is a rear view of the light fixture shown in FIG. 1 ;
FIG. 3 is a side view of the light fixture shown in FIGS. 1 and 2 ;
FIG. 4 is a front view of a light fixture, in accordance with another embodiment of the present invention;
FIG. 5 is an exemplary view of the outside of a window looking in, with a light active; and
FIG. 6 is a diagram showing a house with four light fixtures emitting light, in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
FIG. 1 is a diagram showing a front view of an adjustable lighting system having a lighting unit 10 mounted in a window 12 , in accordance with one embodiment of the present invention. The lighting unit 10 has a light source that is directed through a lens 14 . The lighting system also includes a mounting arm 16 . The lighting unit 10 is shown adjustably attached to the mounting arm 16 that mounts outside the window 12 frame to, for example, the wall, the window sill, the ceiling, or otherwise to allow the light source in the light fixture to direct light out through the window 12 . In this embodiment, the lighting unit 10 attached to the mounting arm 16 may be adjustable as to direction. For example, the light may be adjusted up, down, right, or left. The lens may also be adjustable as to focus. This allows the light to be adjusted to maximize illumination at a specific distance, or be de-adjusted to minimize impacting neighbors. The light is typically mounted adjacent to the window 12 in order to minimize reflected glare from the light, while maximizing its ability to obstruct a view of the inside. Persons skilled in the art will appreciate that while illustrative embodiments are shown in the context of a house, the present invention is applicable to other enclosed spaces such as commercial buildings such as offices, automobiles and trucks, recreational vehicles, boats, etc.
The light source is typically electrically powered. This may be accomplished, for example, by running a wire down inside of or along side of the mounting arm 16 from a power source outside the window. Another alternative is to supply the electricity to the light source with batteries. In yet another embodiment, the light may ultimately be solar powered, with the light charging a battery during the day, and then utilizing the battery to power the light after dark. Other sources of power are also within the scope of the present invention. The lights may be turned on and off by electronic or electro-mechanical switches, timers, with a light sensor, or remotely, utilizing, for example, X10 technology which typically communicates over AC power lines within a home, or a combination of one or more of these techniques. Other methods of turning the lights on and off are also within the scope of the present invention.
The type of light source utilized may also vary with different embodiments of the present invention. The light source may be incandescent, fluorescent, LCDs, LEDs, or may be other light source types, currently available, or later invented. LCDs and LEDs are very attractive in this invention since they can produce significant glare without generating as much light shining into a neighbor's windows. Other types of lights are also within the scope of the present invention. The light source may have more than one level of brightness, such as a two-level system with a high and low brightness output. In one embodiment, the lights are relatively white in color, while in other embodiments, other light colors are utilized. Furthermore, a “mood light” may be mounted on the back of the light fixture to provide soft illumination in the room containing the light.
The light can be used on residential and commercial properties, recreational vehicles and tents. One or more lights can be placed on windows, doors (since many have windows on them to look through), and garage doors that often have windows on them. The shape of the light or lighting unit may be square, rectangular, triangular, or round. The light may also take the form of a pendulum; a light that is fixed on the ceiling or wall, which shines out of the window. Other shapes and configurations are also within the scope of the present invention.
Furthermore, the lighting system may include a security camera or other security device, either mounted separately or integrated into the lighting system. The focus of the lens 14 , or other parameters such as the brightness of the light source, may be dynamically adjusted by the security system, for example, on command, or in response to a motion, heat, or other detector. The system may also provide an audible warning comprising either a verbal warning or other sound.
FIG. 2 is a rear view of the lighting unit 10 shown in FIG. 1 . The rear of the lighting unit is shown in a window 12 , along with the mounting arm 16 from which the light source is attached.
FIG. 3 is a side view of the lighting unit 10 shown in FIGS. 1 and 2 . The lighting unit 10 is shown supported by a mounting arm 16 . Also shown in this FIG. is a lens 14 that may be adjustable in order to focus or unfocus the light being emitted by the light source.
FIG. 4 is a front view of a lighting unit 10 , in accordance with another embodiment of the present invention. A lens 14 is shown attached to the front of the light source. The lens 14 may be adjustable in order to focus or unfocus the light being emitted by the light source.
FIG. 5 is an exemplary view of the outside of a window 12 looking in, with a light active. The light shown from the light source is somewhat unfocused in this FIG., in order to reduce the amount of light that might affect neighbors.
FIG. 6 is a diagram showing a house with seven lighting systems emitting light, in accordance with one embodiment of the present invention. The lighting system is shown in four windows, the window in the front door, and in two windows in the attached garage. As can be seen in FIGS. 5 and 6 , the present invention makes it difficult to see through a window into a house or business.
Those skilled in the art will recognize that modifications and variations can be made without departing from the spirit of the invention. Therefore, it is intended that this invention encompass all such variations and modifications as fall within the scope of the appended claims.
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A lighting system includes a lighting unit and a mounting structure. The lighting unit is mounted adjacent to a window to shine outward, obstructing a view of the inside, while allowing those inside a clear, lighted view of the outside. The lighting unit may be powered by electrical wiring, battery, or solar. Light is preferably adjustable in various directions. The lighting system provides additional security and privacy.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S. application Ser. No. 12/496,254 filed on Jul. 1, 2009, the disclosure of which is incorporated herein in its entirety by reference, which is based on and claims the benefit of Korean Patent Application No. 10-2008-0096912, filed on Oct. 2, 2008, the disclosure of which is incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a hot stamping method used in sheet metal forming, specifically in production of high-strength steel components for crash-relevant parts in the automotive industry.
[0003] Lightweight and high-strength body is a main issue in the automotive industry. The hot stamping technology was proposed by Norrbottens Jarnverk AB in Sweden in the early 1970s. In GB Patent No. 1490535 issued to this company, the hot stamping technology is disclosed in detail.
[0004] To obtain a vehicle body part having tensile strength of 1 GPa or more by the hot stamping process, the microstructure of a steel blank has to be transformed from austenite to martensite by the quenching process in a press forming apparatus. For the hot stamping, boron steels are used which contains carbon of about 0.2 wt % and uses manganese (Mn) and boron (B) as elements for improving heat treatment performance.
[0005] In the hot stamping process, the blank is heated to an austenitization temperature or more, for example, up to 950° C., and then formed in a press forming apparatus, which provides excellent formability and reduces spring-back or delayed fracture, particularly in high-strength parts.
[0006] During the hot stamping process, however, surface oxidation of the blank is occurred, and thus oxide scale on the surface of the hot-pressed body part needs to be removed through a descaling process. In order to remove the descaling process, aluminized steel sheets were proposed by Arcelormittal.
[0007] For the hot stamping, the blank may be heated in an electric resistance furnace to a temperature between 880° C. and 950° C. to form austenite. The electric resistance furnace may have heating elements provided in its walls and an electric current is directed through the heating elements where it is dissipated as heat. The thermal energy is transferred to the blank by radiation and convection. It takes between 12 minutes and 17 minutes to austenitize a blank of 1.2 mm thick using the electric resistance furnace or a gas furnace, which causes decrease the operating speed and increases the production cost of the hot stamping. Furthermore, the length of the heating furnace when using the electric resistance furnaces and the gas furnaces needs to be extended for the hot stamping, ranging from 23 m to 30 m. This means that large space-based facilities are needed for the hot stamping.
SUMMARY
[0008] High frequency induction heating may be used for local strengthening of vehicle body parts. A steel body part may be heated up to 1000° C. or more within several seconds by the high frequency induction heating. If it is possible to use the high frequency induction heating for the hot stamping, the length of the heating furnace and the heating time to austenitize blanks can be reduced. Such a fast temperature increase by the high frequency induction heating, however, may cause deformation of the blank. The high frequency induction heating was merely used just for a heat treatment of thick or bulky steel products rather than thin steel sheets for the hot stamping.
[0009] The present invention proposes a hybrid heating system having a high frequency induction heating furnace for the hot stamping. High frequency induction heating for press-forming thin steel sheets having a thickness about 0.7 mm to about 1.2 mm has never been adapted before and has never been considered to be possible. The present invention is to overcome the stereotype view and propose an innovative alternative that is able to replace the electric resistance furnace for the hot stamping.
[0010] U.S. Pat. No. 5,922,234 discloses technology for induction heating a slab while transferring the slab by using a roller. However, the slab commonly has a thickness of 50 mm to 300 mm and a very long length. The slab is a bulky metal product having a weight of 10 tons or more, furthermore, 50 tons or more and is obviously different from a blank used in hot stamping according to the present invention.
[0011] The blank is obtained by blanking a cold rolled coil or a parent material having a sheet shape so as to have a size and a shape required for hot stamping. The blank may be a thin sheet having a thickness of 2 mm or less, mostly, a thickness of about 0.7 mm to about 1.2 mm.
[0012] U.S. Pat. No. 5,487,795 discloses technology for heating an impact beam using high frequency induction devices while transferring the impact beam on transfer rollers. However, the impact beam induction-heated in the U.S. Pat. No. 5,487,795 is a bulky metal product previously formed. The impact beam is obviously different from a blank heated for hot stamping in the present invention.
[0013] The high frequency induction heating was not used or proposed for hot stamping at the time of filing U.S. application Ser. No. 12/496,254 and Korean Patent Application No. 10-2008-0096912.
[0014] A hot stamping method according to the present invention includes: performing a high frequency induction heating on a blank in a first heating furnace while transferring the blank; heating the blank transferred from the first heating furnace while transferring the blank in a second heating furnace; and forming and cooling the blank transferred from the second heating furnace in a press forming apparatus
[0015] According to an embodiment, the first heating furnace is surrounded by a housing which may minimize heat loss. However, the heat loss may occur in a portion not completely sealed, in particular, at an inlet of the first heating furnace through which the blank is introduced. The blank is not intentionally cooled during the high frequency induction heating.
[0016] According to an embodiment, the blank is continuously transferred without stopping in the high frequency induction heating in the first heating furnace. The blank is transferred by rollers arranged in a moving direction of the blank. When the blank stops on the rollers in the first heating furnace, a portion of the blank, which contacts the rollers, may be locally cooled. A portion of the blank between the rollers may be sagged.
[0017] According to an embodiment, the first heating furnace may have at least two heating zones in a transfer direction of the blank, the at least two heating zones being controlled at different target temperatures and different heating rates. The blank may be pre-heated at a lower power level, desirably, heated to a temperature of 250° C. in a first heating zone and may be rapidly heated at a higher power level, desirably, heated to a temperature less than 550° C. in a second heating zone. According to such a heating pattern, deformation or distortion of the blank may be prevented even when temperature sharply rises due to the high frequency induction heating. An inverter and an inductor coil independently controlled are installed in each of the first and second heating zones.
[0018] U.S. application Ser. No. 12/496,254 and Korean Patent Application No. 10-2008-0096912 do not emphasize or exactly specify that upper rollers are not provided so as to transfer a blank. However, it is necessary to pay attention that these Applications discloses a feature that deformation of a steel sheet occurring in induction heating is controllable through a space adjustment between an upper roller and a lower roller.
[0019] According to an embodiment, the second heating furnace may be an indirect heating furnace, in particular, an electric resistance furnace or a gas furnace, which transfers heat energy to the blank though at least one of radiation and convection. For example, the electric resistance furnace indirectly heats the blank by applying a current to heating elements installed on a furnace wall. The gas furnace uses radiant tubes. The blank may be heated to an austenitization temperature of the blank or more in the second heating furnace.
[0020] According to an embodiment, the press forming apparatus includes an upper die and a lower die, which each include a cooling channel formed therein. A high strength body part having a martensite structure is manufactured by forming and quenching the blank heated to the austenitization temperature or more in the second heating furnace
[0021] According to embodiments of the present invention, the length and the space for the heating system can be reduced by 50% or more compared to the related art, and the production cost of hot stamping can be significantly reduced.
[0022] According to the hot stamping method of the present invention, it is possible to cost-effectively provide a high strength vehicle body part having excellent quality.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Embodiments of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which:
[0024] FIG. 1 is a block diagram of a hot stamping process according to an embodiment of the present invention;
[0025] FIG. 2 is a schematic diagram of apparatuses in a process order, which are used in a hot stamping process, according to an embodiment of the present invention;
[0026] FIG. 3 is a diagram illustrating a pair of upper and lower rollers provided in a first heating furnace, according to an embodiment of the present invention;
[0027] FIG. 4 is a diagram illustrating lower rollers and induction coils provided in a first heating furnace, according to an embodiment of the present invention;
[0028] FIG. 5 is a diagram illustrating a placement of a pair of upper and lower rollers and an induction coil according to an embodiment of the present invention;
[0029] FIG. 6 is a schematic cross-sectional view taken along line VI-VI of FIG. 4 ;
[0030] FIG. 7 is a diagram illustrating a transit section according to an embodiment of the present invention; and
[0031] FIG. 8 is a diagram illustrating an example in which a position of a blank introduced into the transit section shown in FIG. 7 is regulated by guide pins.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0032] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings Like reference numerals refer to like elements for convenience of description.
[0033] A hot stamping process and apparatuses used therein according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 .
[0034] Referring to FIGS. 1 and 2 , the hot stamping process includes heating a blank in a heating system, forming and cooling the heated blank in a press forming apparatus 600 , and loading the press-formed blank onto a conveyor 800 . Transfer robots 500 and 700 are positioned to transfer the blank between the heating system and the press forming apparatus 600 , and between the press forming apparatus 600 and the conveyor 800 , respectively.
[0035] The heating system includes a feed section 100 , first and second heating furnaces 200 and 300 , and a transit section 400 .
[0036] As shown in FIG. 2 , the feed section 100 includes a plurality of feed rollers 110 arranged in a transfer direction of the blank to feed the blank to the first heating furnace 200 . The length of the feed section 100 may be adjusted according to a size of the blank to be fed, and as needed, the feed rollers 110 may be made of stainless steel.
[0037] As shown in FIG. 2 , the first heating furnace 200 is a high-frequency induction furnace having two heating zones 200 a and 200 b. The target temperatures of heating the blank in the two heating zones 200 a and 200 b are different from each other. Each heating zone is provided with induction coils 220 connected to a separate inverter (not shown). Output of the inverter may be adjusted through a frequency modulation.
[0038] The target temperature of the first heating zone 200 a using a relatively low frequency may be 250° C. and the target temperature of the second heating zone 200 b using a relatively high frequency may be 550° C. or less. By heating the blank using the two heating zones, it is possible to prevent or suppress deformation or distortion of the blank caused by a sharp increase in temperature.
[0039] As shown in FIGS. 2 to 4 , in the first heating furnace 200 , a plurality of pairs of upper and lower rollers 210 for transferring the blank are arranged in a lengthwise direction of the first heating furnace 200 , and the induction coils 220 are alternately arranged with the pairs of upper and lower rollers 210 in the lengthwise direction of the first heating furnace 200 . Referring to FIG. 5 , the induction coil 220 may continuously extend from an upper side between the upper rollers 210 a to a lower side between the lower rollers 210 b. The induction coils 220 are insulated and/or coated to avoid the spark caused by contact with the blank.
[0040] The blank is transferred by the lower rollers 210 b which are rotated. The upper rollers 210 a are not provided to transfer the blank. When the blank is not deformed, the upper rollers 210 a do not contact the blank.
[0041] Referring to FIG. 6 , the upper rollers 210 a are arranged so as to be spaced apart from a blank 1 by a certain distance D 1 . When the blank 1 is deformed in a thickness direction thereof in high frequency induction heating, the certain distance D 1 is set to a distance capable of suppressing or blocking the deformation of the blank 1 to a certain degree or less. Desirably, the certain distance D 1 is 30 mm to 40 mm. The induction coils 220 may be spaced apart from the blank 1 by a distance (=distance D 1 +distance D 2 ) in a rear of the upper and lower rollers 210 such that the blank 1 does not contact the induction coils 220 .
[0042] The upper rollers 210 a rotate together with the lower rollers 210 b, at least while the blink 1 is transferred by the lower rollers 210 b. The upper rollers 210 a rotate in a direction opposite to a rotation direction of the lower rollers 210 b, i.e., a direction in which the transferred blank 1 moves forward. After the blank 1 is blocked by the upper rollers 210 a, the rotating upper rollers 210 a allow the blank 1 to smoothly move in a transfer direction and allow additional problems not to occur.
[0043] When a deformation degree of a blank is properly controlled in the high frequency induction heating, some degree of the deformation in the blank may be alleviated to a negligible degree in a subsequent heating process.
[0044] The transfer speed of the blank in the first heating furnace 200 is controlled within a range from 70 mm/sec to 90 mm/sec. Referring to FIGS. 3 to 5 , both ends of the upper and lower rollers 210 a and 210 b pass through insulation panels 230 and then mounted on Bakelite panels 240 which forms the housing of the first heating furnace 200 . The Bakelite panels 240 are used for shielding the influence of high frequency as well as insulation and strength of the housing. The both ends of the upper and lower rollers 210 a and 210 b passing through these
[0045] Bakelite panels 240 are connected with drive units for rotating the upper and lower rollers 210 a and 210 b. Dampers may be provided with the drive units, particularly in bearings to which the upper rollers 210 a are connected to absorb the impact from the blank passing on the lower rollers 210 b.
[0046] The upper and lower rollers 210 a and 210 b are made of a hollow ceramic material for insulation and have extensions 250 to connect the upper and lower rollers 201 a and 210 b to drive units.
[0047] The second heating furnace 300 may be an indirect heating furnace. An electric resistance furnace or a gas furnace may be used for the second heating furnace 300 . The blank may be heated to a temperature of Ac 3 or more of the blank (about 950° C.) in the second heating furnace 300 .
[0048] As shown in FIG. 2 , the second heating furnace 300 has five heating zones. The front three heating zones may constitute a heating section 300 a for heating the blank to a temperature of Ac 3 or more. The forth heating zone may be a soaking section 300 b to make sure that the blank is heated uniformly. The fifth heating zone may be a standby section 300 c to confirm that the blank is fully heated and discharge it at high speed for press-forming. For indirect heating, heating elements 320 are placed apart from the blank being transferred in the second heating furnace 300 . The heating elements 320 can be provided on the top wall of the second heating furnace 300 .
[0049] As shown in FIG. 2 , transfer rollers 310 for transferring the blank are arranged along the second heating furnace 300 . The standby section 300 c of the second heating furnace 300 is followed by the transit section 400 having conveyer rollers 410 .
[0050] A blank position detection sensor 330 and a temperature detection sensor 340 are positioned in the standby section 300 c. The position detection sensor 330 for detecting whether or not the blank enters the standby section 300 c and is placed in the standby section 300 c throughout the entire length thereof. The temperature detection sensor 340 is for confirming if the blank entered into the standby section 300 c is sufficiently heated up to 950° C.
[0051] The transfer speed of the blank in the heating section 300 a is equal to that in the soaking section 300 b. The transfer speed of the blank in the standby section 300 c is also equal to those in the heating and soaking sections 300 a and 300 b before the blank is discharged from the standby section 300 c. When it is confirmed that the blank completely enters the standby section 300 c and is heated, the transfer speed of the blank in the standby section 300 c increases and the blank is discharged to the transit section 400 . The discharging timing may be determined on the basis of information from the position and temperature detection sensors 330 and 340 . After the blank is discharged from the standby section 300 c, the transfer speed thereof is gradually reduced to be equal to those for the heating and soaking sections 300 a and 300 b.
[0052] The temperature of the blank decreases rapidly in several seconds until the blank is formed in the press forming apparatus 600 after being discharged from the standby section 300 c.
[0053] Referring FIGS. 7 and 8 , guide pins 420 are installed upwards between the neighboring conveyer rollers 410 to guide the blank in a right position. The conveyer rollers 410 rotate to move the blank and continue to rotate as long as the blank is thereon. The conveyer rollers 410 rotate while the blank is stopped by the guide pins 420 . This continuous rotation of the conveyer rollers 410 prevents local temperature reduction, deformation, etc. of the blank. A support plate 430 may be placed below the conveyer rollers 410 and movable in an up-and-down direction. A plurality of mounting holes 431 for the guide pins 420 is formed in the support plate 430 along the axial direction of the conveyer rollers 410 . The support plate 430 is connected to a frame 401 of the transit section 400 .
[0054] As shown in FIG. 2 , the blank on the transit section 400 is transferred to the press forming apparatus 600 having upper and lower dies 610 and 620 , and then formed and heat-treated. The upper and lower dies 610 and 620 are each provided with cooling channels for heat treatment of the blank. The hot-formed product is discharged and loaded on the conveyor 800 by the second transfer robot 600 .
[0055] As shown in FIG. 1 , the hot stamping process according to the embodiment includes a first heating process, a second heating process, a press-forming and cooling process, and a post treatment process. An example of the post treatment process is to trim an edge of a part which is press-formed and cooled.
[0056] Boron steel having an aluminium alloy coating layer may be used as a material of the blank used in the hot stamping process according to the embodiment. In an example, the material of the blank may include 0.4 wt % or less of carbon (C), 0.5 wt % to 2.0 wt % of manganese (Mn), and 0.0005 wt % to 0.1 wt % of boron (B). Furthermore, the material of the blank may be boron steel including 0.2 wt % to 0.25 wt % of carbon (C), 1.10 wt % to 1.35 w % of manganese (Mn), 0.15 wt % to 0.35 wt % of silicon (Si), 0.15 wt % to 0.30 wt % of chrome (Cr), 0.02 wt % to 0.06 wt % of aluminium (Al), 0.002 wt % to 0.004 wt % of boron (B), 0.02 wt % to 0.05 wt % of titanium (Ti), and 0.008 wt % or less of sulphur (S).
[0057] The austenitization temperature may be A 3 temperature of the boron steel at which a mixture phase of ferrite and austenite is converted into a single phase. The boron steel sheets may have a mixture phase of pearlite and ferrite at room temperature.
[0058] While the present invention has been shown and described in connection with the exemplary embodiment, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.
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Provided is a hot stamping method for manufacturing high strength vehicle body parts. The hot stamping method includes: high frequency induction heating a blank in a first heating furnace while transferring the blank; heating the heated blank to an austenitization temperature or more of a corresponding blank while transferring the heated blank from the first heating furnace to a second heating furnace; and drawing the blank heated to the austenitization temperature or more in the second heating furnace to form and cool the blank by using a press forming apparatus. According to the hot stamping method, it is possible to achieve excellent productivity and reduce energy.
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BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to an insulating film for use in motor of refrigeration compressor. More particularly, the present invention relates to an insulating film for use in motor of refrigeration compressor, which has excellent resistances to the substitute flon and refrigerating machine oil (e.g. synthetic lubricating oil) used in particular combination in the refrigeration compressor and moreover imparts deterioration resistance to the refrigerating machine oil.
(2) Description of the Prior Art
Flon gases, which have been used as a refrigerant for air conditioner or refrigerating machine, are believed to be a cause for ozone layer destruction and global warming, and the use of particular flons having a high ozone depletion potential, such as R11 (CCl 3 F), R12 (CCl 2 F 2 ) and the like must be totally banned by 2,000 according to the decision made at the Copenhagen Agreement in November 1992, amended in the Montreal Protocol. In this connection, change of flon gases to substitute flons such as hydrofluorocarbons (HFC), hydrochlorofluoro-carbons (HCFC) and the like is taking place. Of the substitute flons, R134a (CH 2 F--CF 3 ) is drawing high attention and is coming to be used practically.
R134a, however, is not compatible with mineral oils which have been used as a lubricating oil for refrigeration compressor. Hence, synthetic oils of polyoxyalkylene glycol type, ester-modified polyoxyalkylene glycol type, ester type or the like are coming to be used as a new lubricating oil for refrigeration compressor.
The motor of air conditioner or refrigerating machine is used as a motor of compressor for refrigerant and is constantly placed in an atmosphere where the above-mentioned refrigerant and lubricating oil coexist. Therefore, when the compressor is in operation, the coil of the motor comes in contact with a gaseous refrigerant of high temperature and high pressure, a lubricating oil containing a large amount of the refrigerant dissolved therein, etc.; when the compressor is in stop, a liquid-state refrigerant is accumulated inside the compressor. Thus, the insulating film used for insulation of the above motor is exposed to such conditions over a long period of time and yet is required to have a semi-permanent life.
As such an insulating film, there has been widely used a polyethylene terephthalate (hereinafter abbreviated to PET) film for its balanced properties in heat resistance, solvent resistance, electrical insulation, mechanical strengths, etc. The PET film, however, is liable to hydrolysis by the water present in refrigerating machine oil of polyalkylene glycol type, ester-modified polyalkylene glycol type, ester type or the like, and has inevitably shown significant reduction in mechanical strengths and electrical insulation.
Also in the PET film, the low-molecular materials, etc. contained therein are extracted by the above-mentioned synthetic lubricating oil having a higher solvency for organic substances than mineral oils have, resulting in sludge formation and film embrittlement; thus, there has been a fear of reduction in compressor life.
Recently, as the output of compressor has become larger, the heat resistance and pressure resistance requirements for the insulating film of compressor motor have also become larger. In this connection, study on use of polyimide film, polyamideimide film or the like is under way. These films, however, are not satisfactory because they cause hydrolysis by the water contained in the refrigerating machine oil used in combination with a substitute flon and thereby generate organic acids, which may invite deterioration of the refrigerating machine oil and resultant reduction in refrigerating capacity.
OBJECT AND SUMMARY OF THE INVENTION
In view of the above situation, the object of the present invention is to provide an insulating film for use in motor of refrigeration compressor, which has excellent hydrolysis resistance, generates no sludge, resultantly prevents reduction in insulation, and further has a deterioration resistance to refrigerating machine oil.
In order to solve the above-mentioned problems of the prior art, the present inventors made a study. As a result, the present inventors found out that the above object can be achieved by using, as an insulating film, a carbodiimide film obtained by adding, to a base film, a particular compound having at least one carbodiimide group in the molecule, or by coating the particular compound on the base film, or by using essentially the particular compound. The finding has led to the completion of the present invention.
According to the present invention, there is provided an insulating film for use in the motor of a refrigeration compressor using a substitute flon and a refrigerating machine oil in particular combination, which film is obtained by adding, to a base film, a compound having at least one carbodiimide group, represented by the following formula (1) ##STR5## (wherein R 1 , is an isocyanate residue, and n 1 is an integer of 1 or more), or the formula (2) ##STR6## (wherein R 2 is an isocyanate residue; R 3 and R 4 are each a terminal group; and n 2 is an integer of 1 or more), or the formula (3) ##STR7## (wherein R 5 and R 6 are each an isocyanate residue; Y is a residue of a compound having a functional group reactive with isocyanate; and n 3 and m are each an integer of 1 or more), or the formula (4) ##STR8## (wherein R 7 is an isocyanate residue; R 8 and R 9 are each a terminal group; and n 4 is an integer of 1 or more).
According to the present invention, there is also provided an insulating film for use in the motor of a refrigeration compressor using a substitute flon and a refrigerating machine oil in particular combination, which film is obtained by coating, on the surface of a base film, a compound having at least one carbodiimide group, represented by the above formula (1) or the formula (2) or the formula (3) or the formula (4).
According to the present invention, there is further provided an insulating film for use in the motor of a refrigeration compressor using a substitute flon and a refrigerating machine oil in particular combination, which film is made essentially of a compound having at least one carbodiimide group, represented by the above formula (1) or the formula (2) or the formula (3) or the formula (4).
DETAILED DESCRIPTION OF THE INVENTION
The present invention is hereinafter described in detail.
In the present invention, "insulating film for use in motor of refrigeration compressor" refers to, for example, a film used in a motor of refrigeration compressor which has a first winding and a second winding, in the form of layer insulation, slot insulation, slot wedge or the like to separate the windings from each other for prevention of their contact.
In the present invention, the insulting film for use in motor of refrigeration compressor is obtained by adding to a base film, or coating on the surface of a base film, a compound having at least one carbodiimide group, or, is made essentially of a compound having at least one carbodiimide group (the compound is hereinafter abbreviated to "carbodiimide compound" in some cases).
The compound having at least one carbodiimide group, used in the present invention includes group (I) compounds represented by the following formula (1): ##STR9## (wherein R 1 is an isocyanate residue, and n 1 is an integer of 1 or more); group (II) compounds represented by the following formula (2): ##STR10## (wherein R 2 is an isocyanate residue; R 3 and R 4 are each a terminal group; and n 2 is an integer of 1 or more); group (III) compounds represented by the following formula (3): ##STR11## (wherein R 5 and R 6 are each an isocyanate residue; Y is a residue of a compound having a functional group reactive with isocyanate; and n 3 and m are each an integer of 1 or more); and group (IV) compounds represented by the following formula (4): ##STR12## (wherein R 7 is an isocyanate residue; R 8 and R 9 are each a terminal group; and n4 is an integer of 1 or more).
In the formula (1) of the group (I) compounds, R 1 can be exemplified by the following groups: ##STR13##
In the formula (1) of the group (I) compounds, n 1 is an integer of 1 or more. The formula (1) indicates a state in which polymerization has proceeded sufficiently. When polymerization has not proceeded sufficiently, the group (I) compounds are represented more appropriately by the following formula: ##STR14## (wherein R 1 s may be the same or different). This applies also to the formula (3) of the group (III) compounds described later.
In the formula (2) of the group (II) compounds, R 3 and R 4 are each a terminal group by a residue of a compound having a functional group such as --NH 2 , --NHX, --COOH, --SH, --OH or --NCO, or the following structures: ##STR15##
In the formula (2) of the group (II) compounds, n 2 is an integer of 1 or more; and R 2 can be exemplified by the same groups as mentioned with respect to R 1 in the formula (1) of the group (I) compounds.
In the formula (3) of the group (III) compounds, Y is a residue of a compound having a functional group reactive with isocyanate, and can be exemplified by the following structures: ##STR16## wherein Z is an alkylene group, a bivalent cycloalkyl group, a bivalent cycloalkyl group having a substituent(s) , a bivalent aryl group, a bivalent aryl group having a substituent (s), one of the following groups: ##STR17## or a group wherein one of the above structures has a substituent(s) such as lower alkyl group, lower alkoxy group or the like!.
Therefore, the group (III) compounds represented by the formula (3) are carbodiimide copolymers. In the formula (3) of the group (III) compounds, n 3 and m are each an integer of 1 or more; R 5 can be the same group as mentioned with respect to R 1 in the formula (1) of the group (I) compounds; and R6 can be the same group as mentioned with respect to R 1 in the formula (1) of the group (I) compounds, or the same group as mentioned with respect to bivalent Z in the formula (3) of the group (III) compounds.
In the formula (4) of the group (IV) compounds, R 8 nd R 9 can each be exemplified by isocyanate residues such as shown below: ##STR18## Incidentally, R 8 and R 9 may be the same or different.
A group (IV) compound of the formula (4) wherein n 4 is 0, can be obtained by reacting two monoisocyanates each having the above-mentioned isocyanate residue.
The present insulating film for use in motor of refrigeration compressor can be obtained by, as mentioned above, adding the above-mentioned carbodiimide compound to a base film heretofore used as an insulating film for motor of refrigeration compressor, or by coating the carbodiimide compound on the base film, or by making an insulating film essentially with the carbodiimide compound.
When the carbodiimide compound is added to a base film heretofore used as an insulating film for motor of refrigeration compressor, the amount of the carbodiimide compound added is, for example, 0.05-50 parts by weight, preferably 0.1-30 parts by weight per 100 parts by weight of the base film. When the amount is less than the above lower limit, no intended effect is obtained. When the amount is more than the above upper limit, increase in effect is not so high as expected and, in some cases, gives a film of impaired properties.
The base film can be a known film such as polyester film, polyimide film, polyamideimide film, polyetherimide film, aromatic polyamide film, polyhydantoin film, polyparabanic acid film, polyethersulfone film or the like.
The method of adding the carbodiimide compound to the base film may be a known method. When the base film is, for example, a thermoplastic film, the method includes, for example, (1) a method of adding a carbodiimide compound in production of resin pellets which is a raw material of base film, and (2) a method of adding a carbodiimide compound to a film produced by casting or to a material to be casted.
When the carbodiimide compound is coated on the base film, the compound is preferably a film-formable compound selected from the group (I) compounds, the group (II) compounds, the group (III) compounds and the group (IV) compounds. Preferred are group (I) compounds wherein n 1 ≧20; group (II) compounds wherein n 2 ≧30; group (III) compounds wherein n 3 ≧20 and m≧1, or n 3 ≧1 and m≧15; and group (IV) compounds wherein n 4 ≧20.
The method used for coating the carbodiimide compound on the base film can be a known method. There can be used, for example, a method which comprises dissolving a carbodiimide compound having at least one carbodiimide group, in a solvent to prepare a solution, immersing a base insulating film in the solution or coating the solution on the film, subjecting the resulting material to solvent removal, and heat-treating the solvent-removed material. The thickness of the carbodiimide compound layer formed on the base film is 1-50 μm, preferably 5-20 μm. When the thickness is less than 1 μm, no intended effect is obtained. When the thickness is more than 50 μm, increase in effect is not so high as expected and, in some cases, gives a film of impaired properties.
When the thickness can be more than 50 μm, the present insulating film can be made with a group (I), or group (II) or group (III) compound alone.
The method used for making an insulating film essentially with the carbodiimide compound can also be a known method. There can be used, for example, a method which comprises casting a solution containing the carbodiimide compound, and forming the carbodiimide compound powder under pressure and heating.
The present invention is hereinafter described by way of Examples and Test Example. However, the present invention is not restricted thereto.
In the Examples, the following compounds 1-5 each having a carbodiimide group(s) were used. Incidentally, the expression n=∞ used in the compounds 1, 4 and 5 indicates that the terminal functional groups are not detected by FT-IR analysis and are substantially absent and the compounds are high-molecular compounds. ##STR19##
EXAMPLE 1
100 parts by weight of commercial polyethylene terephthalate pellets for film making and 8 parts by weight of the compound 2 were dry-blended. The blend was placed in a hopper and fed into an extruder to knead the blend at 240-270° C. The kneaded material was extruded from the extruder T die with stretching being applied, to prepare an intended film (1) having a thickness of 100 μm.
EXAMPLE 2
54.0 g of 80-TDI (a 80/20 mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate) was reacted at 120° C. for 4 hours in the presence of 0.11 g of a carbodiimidization catalyst (1-phenyl-3-methyl-2-phospholene-1-oxide) in 500 ml of tetrachloroethylene to obtain a solution of a polycarbodiimide having a structure of compound 1, which showed no absorption of isocyanate group by infrared absorption analysis (hereinafter abbreviated to IR). The solution was subjected to film formation by casting, to obtain a polycarbodiimide film (2) having a thickness of 80 μm.
EXAMPLE 3
A commercial polyethylene terephthalate film having a thickness of 50 μm was immersed in the polycarbodiimide solution of Example 2 to prepare an intended film (3) having a thickness of 80 μm, which is a polyethylene terephthalate film having, on each side, a compound 1 layer having a thickness of about 15 μm.
EXAMPLE 4
A commercial polyamideimide powder was dissolved in N-methyl-2-pyrrolidone to obtain a solution containing 20% by weight of the polyamideimide powder. To 100 parts by weight of this polyamideimide solution was added 7 parts by weight of an N-methyl-2-pyrrolidone solution containing 20% by weight of the compound 4, to prepare a varnish. The varnish was subjected to film formation by casting, followed by solvent removal and annealing, to prepare an intended film (4) having a thickness of 80 μm, having amide group, imide group and carbodiimide group.
EXAMPLE 5
17.4 g of 80-TDI was reacted with 16.1 g of benzophenonetetracarboxylic acid anhydride in 300 ml of nitrobenzene at 150° C. for 4 hours. Thereto was added 200 ml of N-methyl-2-pyrrolidone and 0.02 g of a carbodiimidization catalyst, and a reaction was conducted at 150° C. for 20 hours to obtain a solution of a polycarbodiimide having a structure of compound 5, which showed no absorption of isocyanate group by IR. The solution was subjected to film formation by casting, followed by solvent removal, to obtain an intended polycarbodiimide film (5) having a thickness of 80 μm.
EXAMPLE 6
57.8 g of p-MDI (pure diphenylmethane diisocyanate) was reacted with 1.1 g of phenyl isocyanate in the presence of 0.12 g of a carbodiimidization catalyst (1-phenyl-3-methyl-2-phospholene-1-oxide) in 500 ml of tetrahydrofuran at 65° C. for 20 hours, to obtain a solution of a polycarbodiimide having a structure of compound 3, which showed no absorption of isocyanate group by IR. The solution was subjected to film formation by casting, to obtain a polycarbodiimide film (6) having a thickness of 80 μm.
EXAMPLE 7
The polycarbodiimide film having a structure of compound 1, obtained in Example 2 was treated at 200° C. for 5 minutes to obtain an intended polycarbodiimide film (7) wherein part of the carbodiimide groups was dimerized to form a crosslinked structure.
Test Example
50 ml of a commercial ester type oil was placed in a 100-ml autoclave. In the autoclave were also placed three rectangular (3 cm×6 cm) test pieces prepared by cutting one of the films prepared in Examples 1-7, so that the test pieces were immersed in the oil. Then, the autoclave was tightly sealed, heated at 175° C. for 10 days, and then opened. Thereafter, (1) the total oxidation numbers of the oil before and after the heating and (2) the tensile strengths of the film before and after the heating were measured. The results are shown in Table 1.
COMPARATIVE EXAMPLE 1
50 ml of a commercial ester type oil and a commercial polyethylene terephthalate film having a thickness of 80 μm were heated in an autoclave in the same manner as in Test Example. Then, (1) the total oxidation numbers of the oil before and after the heating and (2) the tensile strengths of the film before and after the heating were measured in the same manner as in Test Example. The results are shown in Table 1.
COMPARATIVE EXAMPLE 2
50 ml of a commercial ester type oil alone was heated in an autoclave in the same manner as in Test Example. Then, the total oxidation numbers of the oil before and after the heating were measured. The results are shown in Table 1.
TABLE 1______________________________________ Total Oxidation Numbers Tensile Strength of Film of Oil (mg KOH/g) (kfg/mm.sup.2) Before After Before After Heating Heating Heating Heating______________________________________Film 1 0.02 0.25 15.4 9.8Film 2 0.02 0.18 17.9 14.5Film 3 0.02 0.15 14.8 11.0Film 4 0.02 0.21 13.4 11.7Film 5 0.02 0.20 14.1 12.6Film 6 0.02 0.17 13.3 10.2Film 7 0.02 0.19 15.9 13.6Comparative 0.02 0.35 16.2 Unable toExample 1 Measure*Comparative 0.02 0.33 -- --Example 2______________________________________ *Test pieces deteriorated and became brittle, and could not be fitted to tensile strength tester.
The present insulating film for use in motor of refrigeration compressor, comprising a polycarbodiimide, as compared with conventional insulating films, has higher resistances to refrigerating machine oil and refrigerant and can prevent deterioration of insulation.
Further, with the present insulating film for use in motor of refrigeration compressor, the carbodiimide groups possessed by the polycarbodiimide of the film can capture (a) the acid components (e.g. carboxylic acids and phosphoric acid) generated by the decomposition of refrigerating machine oil, refrigerant and additives and (b) water which causes the hydrolysis of ester bond of refrigerating machine oil, and thereby can prevent oxidation number increase in refrigeration compressor system.
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The present invention provides an insulating film for use in the motor of a refrigeration compressor using a substitute flon and a refrigerating machine oil in particular combination, which film is obtained by adding to a base film, or coating on the surface of a base film, a compound having at least one carbodiimide group, or, which film is made essentially of a compound having at least one carbodiimide group, represented by the following formula (1): ##STR1## or the following formula (2): ##STR2## or the following formula (3): ##STR3## or the following formula (4): ##STR4## This insulating film can eliminate the problems of the prior art, has excellent resistance to hydrolysis and forms no sludge, resultantly can prevent reduction in insulating property, and further has deterioration resistance to refrigerating machine oil.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This non-provisional application is to fulfill the filing requirements of the provisional application 60/767,004 filed on Feb. 26, 2006 which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] Currently if a band or musician would like to sell their music without the aid of a major marketing corporation, they must rely on small impromptu gatherings or gigs to build a name. There is no direct way a musician has to contact the public in the masses and allow their music to be purchased by anyone that wishes to. The Internet goes a long way in providing a medium to sell their music to the masses but the average musician still lacks a major marketing technique to bring in additional customers.
[0003] This Invention allows both radio stations and musicians to sell music and market it to the masses without the aid of any major marketing companies. When a musician is ready to sell to the public they can now contact radio stations directly, however a musician is still unlikely to gain a large amount of funding from just this method as there is no real way of tracking how many listeners would be willing to purchase their music if given the chance. The average listener base is too lazy to look up a website or go to a concert to purchase music. This technology will allow a user to push a button on their radio or a separate hand held device that will allow them to then purchase the song from the Internet at a later date.
[0004] SCA sub carrier data is already used for a great variety of reasons by radio stations to make additional funding. While a radio station broadcasts a song, they can use the SCA data to send out a URL for purchasing the song. When the listener likes the music they hear they can simply press a button on the invention that allows them to purchase it. The invention will in turn store the URL to a memory medium.
[0005] In addition to the added value of listeners being able to make purchases of new music heard on the radio that may not have had a large enough name before for the listener to purchase their music in their local stores, the invention also provides a method for bands to sell their music at concerts. If the band has no Internet server to sell their music, a company may sponsor them online. At the gig or concert, the band's fans would only have to hear the company's name and the band's name in order to search online later for music to purchase from the company. The fan would simply type in the band's name and the company's name into the invention, store it to the invention's memory, and then use the software coupled with that invention on their home computer to locate the songs they want and make the purchase.
[0006] This invention provides a connection between all the many ways we have to purchase music today with our day to day life of hearing music we love. While there are other technologies out there that provide such a service, none are as adaptable or as cheap to all participants as this.
[0007] While there have been many different technologies that use SCA data to produce profits for radio stations, none provides the service this invention does while promoting all participants involved in selling the music. For example, US Publication number 20040128514 covers the watermarking of music to track music heard so a user may store the data to purchase the music and purchase it latter. This requires the use of complicated watermarking software and license rights small bands may not have when they are just getting started. The above invention also requires a complicated interpretation of the audio signal to identify watermarks. Separating the purchase information from the audio track and broadcasting it in an SCA channel allows bands to release music to radio stations without the need for expensive watermarking software.
[0008] The patent publication 20040128514 also requires a complicated matching system to allow songs received by the player to be identified with an online database. In this invention the purchasing of music by a band can happen in multiple ways, all independent of each other.
[0009] If the SCA data provides a URL, the listener may purchase the music directly from that URL. This allows profit from both the radio station and the artist by purchasing through the radio station's website. If there is no SCA data available, the user may still enter keywords to search later.
[0010] If the user is at a concert, purchasing the band's music maybe as easy as storing the band's name along with the company name. The user would simply input the names using the keypad, and then store it to the memory device. Once the user returns to their home PC, the data can be used by a program that was shipped with the product that allows searching key servers for the company name or band name. This search will yield a type of profile allowing the download and purchase of the band's music. Either through the band's website, or the company that is sponsoring the band.
[0011] In the case that there is no sponsor and no know band website, keywords can be used. A keywords, such as a series of song lyrics or an artist name can be typed into the device. The search program on their home PC will use this data to search major music purchasing websites such as Amazon.com, Itunes, Wal-Mart, and others. Once a website returns with the keywords, the results are displayed to the user so they can fine tune their search if need be.
[0012] This invention takes out all the overhead of major marketing involved for bands to make their name huge. It provides the most seamless interaction between a band and their listeners without the need for expensive software tools, marketing companies, or even radio stations to play their music. An artist can hang a sign around their neck with his name, publish their name on one of the central servers the device searches, and anyone may then purchase his/her music. These sales can be used to gain more marketing clout as sales will be tracked for tax purposes. An artist can use the sales of their music as proof that their music is in demand, making radio stations more interested in broadcasting their songs to a wider audience. Once that happens, and a market is shown for the artist's music, even more radio stations may play it to gain more profits.
BRIEF DESCRIPTION OF THE INVENTION
[0013] The system has multiple ways of purchasing music using keywords inputed by the user or stored URLs transmitted through SCA data. The device used in conjunction with the invention allows users to store keywords onto a memory unit using a keypad and uses a display to show user input or stored memory items. A software program uses the data on the memory unit and a PC interface to the device to search key web servers for keywords or uses a specific URLs specified in the data to download the song directly to the user's PC after a purchase has been authorized by the user.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Drawing 100 is a perspective view of how the system will be used in relation to the user, radio stations, sponsored servers, and the artists.
[0015] Drawing 200 is an example of a possible form of the user interface for the device.
[0016] Drawing 300 is a basic overview of some of the components that maybe found in the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] This description is intended only to provide one possible embodiment of the proposed invention. The details that follow should not be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
[0018] Drawing 100 shows an overview of how the technology maybe used. When an Artist wishes to place their music online to sell they have three options, two of which are represented on Drawing 100 .
[0019] The first method is to contact a radio station directly to sell their music. This will require the artist to submit the song they wish to sell to the radio station. The radio station will place the song on their servers 104 so it maybe purchased. When the song is played over the station, the SCA data broadcast ed at the same time as the song will contain the URL data from the Radio Station Server 104 . This SCA data will be decoded, checked for integrity, and decrypted if necessary by a small hand held device 103 . Later the Device 103 will be used in conjunction with software 102 on the user's home PC to communicate with the Radio station's server 104 via the Internet. The purchased will be placed according to whatever purchasing method has been established by the Radio Station Server 104 . This purchase will then split the money made from the purchase and distribute it to the Radio station and the Artist.
[0020] The second method is in the case that there is no SCA data to record. When a User hears a song they like or wish to purchase, they can input keywords such as the artist name, song name, or song lyrics, into the Device 103 and store it for retrieval later. With the Software 102 , the user can then use these keywords to communicate with Central Lookup Server 105 . These servers are standard DNS names that will not change for the duration of the software's version is supported. The Central Lookup Servers 105 contain a large database of artists, band links, companies that sponsor bands through hosting online, and individual links for small time artists that do not have a public place to sell their music. The Central Lookup Servers 105 provide links to Sponsored Servers 101 in which the purchase of the music the user wants can be made. Payments are then divided among the parties responsible for placing the song online and the artist.
[0021] The third method is in the case that no keyword match can be found on the Central Lookup Servers 105 . In this case the User's Software 102 will search preset websites on the Internet to purchase the music they are looking for. This may include Itunes, Amazon.com, Wal-Mart.com, or any website not supported by the Central Lookup Servers 105 .
[0022] The next Drawing is of the User Interface for the Device 200 . The Leds 203 will display the current mode of the device. Possible modes include, Purchase available, Searching for SCA data, Tuning, or Management. If SCA data has been detected and validated by the device a light will indicate this to the user. When this light is active the user may press the purchase button to store the URL data to the memory of the device. When the device has been tuned to a specific radio station, the device will indicate that it is searching for SCA data with a specific light. If the user has just entered a new radio station to tun to, the device will notify the user that it is processing their last request with another light.
[0023] The keypad 201 will include numbers and letters, possibly both on the same key as found on most phones. There will also be mode buttons on the keypad that allow the user to turn off the device, tune to a new station, enter keywords to store into the device, or manage the memory in the device.
[0024] The LCD screen 202 will display a variety of information to the user. It allows the user to view the data in the memory when they access it with the keypad 201 . It will notify the user of any errors the device may have encountered during operation. The LCD 202 will also show the station currently tuned to.
[0025] The third drawing is a basic example of the components in the device 300 . An SCA receiver 301 is used to scan the current station the device is tuned to in order to capture any URL data available. The data captured by the SCA receiver 301 will be decoded by an analog to digital converter 302 . This ADC 302 will be activated when the correct signal has been received by the SCA receiver 301 . Once the ADC 302 has been activated, it begins to store the URL data and any other data attached to the URL to the local buffer. A closing signal will notify the ADC to stop receiving data. The received messaged is decoded and checked for integrity 304 . The ADC 302 is locked down from use until this data has been checked. If an error is generated while the data is being checked, an error is generated and displayed to the user through the user interface 303 (communication not shown on drawing). If the data is simply not valid it is thrown away and the buffer is cleared 304 . The ADC 302 is then reactivated for the next signal to be received.
[0026] There are special SCA signals used to tell the ADC 302 if a new song is being played. At which moment the the buffer 304 moves the previous data in it to a long term storage area available in Memory 307 regardless if the user has pressed the purchase button or not 306 . This is to allow the user to scroll through previously heard songs and select to purchase them later. The number of songs the user can scroll back through depends on the device memory capacity and how much has been allowed for such an action 307 . This clearing of the buffer allows the ADC 302 to store URL data for the next song being played without prompting the user for interaction.
[0027] If no URL signal is identified by the SCA receiver 301 , or no valid data is decoded by the ADC 302 / 304 , then the user has the option of inputing keywords to store for searching later. The user will simply press a button on the user interface 303 that will allow them to add a new entry to the memory. As the user enters the data it is displayed on the LCD screen 303 / 202 . This data likewise is stored into a buffer 305 . When the user is ready to store the keyword(s) they press the store button 306 and the buffer 205 is transferred into the long term memory 307 .
[0028] When the device is connect to a computer's USB port, the USB controller 308 will communicate with the Memory of the device 307 to retrieve any keywords or stored URLs the user has selected for purchasing/searching. This data is then used by the software in the manor described before.
[0029] While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
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Method and apparatus for the purchasing of music using SCA data in common radio waves. This invention allows a portable device to record URLs and keywords inputed by the user for retrieval later by a software program capable of running searches on specified servers or placing a purchase using a specific URL.
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BACKGROUND OF INVENTION
(1) Field of Invention
This invention relates to novel methods for preparing fluorinated organic compounds, and more particularly to methods of producing fluorinated olefins.
(2) Description of Related Art
Hydrofluorocarbons (HFC's), in particular hydrofluoroalkenes such tetrafluoropropenes (including 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf) and 1,3,3,3-tetrafluoro-1-propene (HFO-1234ze)) and pentafluoropropenes (1,2,3,3,3-pentafluoropropene (HFO-1225ye) have been disclosed to be effective refrigerants, fire extinguishants, heat transfer media, propellants, foaming agents, blowing agents, gaseous dielectrics, sterilant carriers, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, displacement drying agents and power cycle working fluids. Unlike chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), both of which potentially damage the Earth's ozone layer, HFCs do not contain chlorine and thus pose no threat to the ozone layer.
Several methods of preparing hydrofluoroalkanes are known. For example, U.S. Pat. No. 5,679,875 discloses methods for manufacturing 1,1,1,2,3-pentafluoropropene and 1,1,1,2,3-pentafluoropropane; U.S. Pat. No. 6,031,141 discloses a catalytic process using chromium-containing catalysts for the dehydrofluorination of hydrofluorocarbons to fluorooolefins; U.S. Pat. No. 5,396,000 discloses a process for producing CF3CHFCH2F utilizing a vapor phase catalytic dehydrofluorination step to produce CF3CF═CHF from CF3CHFCHF2; U.S. Pat. No. 6,548,719 discloses a process for producing fluoroolefins by dehydrohalogenating a hydrofluorocarbon in the presence of a phase transfer catalyst; U.S. Publication No. 2006/0106263 discloses the production and purification of hydrofluoroolefin compounds; and WO98/33755 discloses catalytic process for the dehydrofluorination of hexafluoropropanes to pentafluoropropenes.
Notwithstanding prior teachings applicants appreciate a continuing need for methods of efficiently preparing certain hydrofluorocarbons, particularly pentafluorpropenes such as HFO-1225, including particularly HFO-1225ye.
SUMMARY OF THE INVENTION
In one aspect of the present invention, applicants have developed methods for producing fluorinated organic compounds, including hydrofluoroolefins in general and pentafluoropropenes in particular embodiments, which preferably comprises converting at least one compound of formula (I):
CF n X m CF a X b CH 2 X (I)
to at least one compound of formula (II):
CF 3 CF═CHF (II)
where each X is independently Cl, I or Br; n is 2 or 3; m is 0 or 1; a is 1 or 2; b is 0 or 1; m+n=3; and a+b=2.
The preferred converting step of the present invention comprises catalytic reaction of the compound of formula (I). The catalytic reaction step comprises in preferred embodiments introducing said compound of formula (I) to a reaction system under conditions effective to convert, and preferably convert at least about 50%, more preferably at least about 65%, even more preferably at least about 90%, and even more preferably at least about 95% of said compound of formula (I). It is also generally preferred that said converting step produces a reaction product having at least about 60% selectivity, more preferably at least about 70% selectivity and even more preferably at least about 90% selectivity, to compounds of formula (II), preferably HFO-1225ye. In certain highly preferred embodiment the selectivity to pentatetrafluoropropene is at least about 95%.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
One beneficial aspect of the present invention is that it enables the production of desirable fluoroolefins, such as HFO-1225ye, using relatively high conversion and high selectivity reactions. In addition, the methods of the present invention provided reactions with relatively high yield and relatively high selectivity.
In one preferred aspect of the present invention the reactant comprises a compound of formula I in which n is 3, m is 0, a is 2 and b is 0, namely, CF 3 CF 2 CH 2 Cl, which is preferably converted in substantially single reaction step to the compound of formula (II). The starting compound in such embodiments, namely CF 3 CF 2 CH 2 Cl, can be prepared by methods known in the art, including those outlined above, the conversion of CF 3 CF 2 CH 2 OH via the tosylate, and/or the reduction of CF 3 CF 2 CHCl 2 .
In another preferred aspect of the present invention the reactant comprises a compound of formula I in which n is 3, m is 0, a is 1 and b is 1, namely, CF 3 CFXCH 2 Cl. For convenience, such compounds are sometimes referred to herein for convenience as compounds of formula (IA). In preferred aspects of such formula (IA) embodiments, X is Cl.
In another preferred aspect of the present invention the reactant comprises a compound of formula I in which n is 2, m is 1, a is 2 and b is 0, namely, CF 2 XCF 2 CH 2 Cl. For convenience, such compounds are sometimes referred to herein for convenience as compounds of formula (IB). In preferred aspects of such formula (IB) embodiments, X is Cl.
Conversion of Formula (I) Compounds
The methods of the present invention preferably comprise converting a compound of formula (I) to a fluorolefin, preferably a C3 fluorolefin, more preferably a compound of formula (II), and even more preferably pentafluoropropene.
In certain preferred embodiments, the present converting step is carried out under conditions effective to provide a formula (I) conversion of at least about 40%, more preferably at least about 55%, and even more preferably at least about 70%. In certain preferred embodiments the conversion is at least about 90%, and more preferably about 100%. Further in certain preferred embodiments, the conversion of the compound of formula I to produce a compound of formula II is conducted under conditions effective to provide a formula II selectivity of at least about 25%, more preferably at least about 40%, more preferably at least about 70%, and even more preferably at least about 90%.
This reaction step can be carried out in the liquid phase or in the gas phase, or in a combination of gas and liquid phases, and it is contemplated that the reaction can be carried out batch wise, continuous, or a combination of these. Preferably, however, the reaction is carried out as a gas phase reaction.
For example, in embodiments in which the starting compound comprises 1,1,1,2,2-pentafluoro-3-chloropropane (CF 3 C F 2 CH 2 Cl), a catalyzed gas phase reaction is generally preferred. Although it is contemplated that in such embodiments the reaction step may be preformed using a wide variety of process parameters and process conditions in view of the overall teachings contained herein, it is preferred in such embodiments the catalyst is preferably a carbon- and/or metal-based catalyst, such as activated carbon, fluorinated chromium oxide or fluorinated alumina, with or without added metal salts such as those of cobalt, nickel, barium, magnesium, zinc, or cesium. It is expected that many other catalysts may be used depending on the requirements of particular embodiments in view of the teachings contained herein. Of course, two or more any of these catalysts, or other catalysts not named here, may be used in combination.
In general it is preferred that the catalysts are fluorinated, preferably for a period of from about several hours (eg., 6 hours). In preferred embodiments, fluorination of the catalysts comprises exposing the catalyst to a stream of HF at about reaction temperature and under slight pressure, for example about 5-150 psia.
The gas phase reaction may be conducted, for example, by introducing a gaseous form of a compound of formula (I), and preferably CF 3 CF 2 CH 2 Cl, a compound of formula (IA), a compound of formula (IB), and combinations of these, and optionally HF, into a suitable reaction vessel or reactor. Preferably the vessel is comprised of materials which are resistant to corrosion as Hastelloy, Inconel, Monel and/or fluoropolymers linings. Preferably the vessel contains catalyst, for example a fixed or fluid catalyst bed, packed with suitable means to heat the reaction mixture to the desired reaction temperature.
The use of HF is not believed to be necessary as a reactant to effectively conduct the present methods, but is nevertheless preferred in certain embodiments. For example, for processes in which the starting materials include compounds of Formula (IA), Formula (IB) or combinations of these, it is generally preferred that at least one mole of HF per mole of dichlorotetrafluoropropane is used. The mole ratio of HF:dichlorotetrafluoropropane used in such embodiments preferably is in the range of from about 1:1 to about 9.5:1, and even more preferably from about 1:1 to about 8:2.
While it is contemplated that a wide variety of reaction temperatures may be used, depending on relevant factors such as the catalyst being used and the most desired reaction product, it is generally preferred that the reaction temperature is from about 200° C. to about 600° C., preferably about 375° C. to about 550° C.
In general it is also contemplated that a wide variety of reaction pressures may be used, depending again on relevant factors such as the specific catalyst being used and the most desired reaction product. The reaction pressure can be, for example, superatmospheric, atmospheric or under vacuum, and in certain preferred embodiments is from about 15 to about 120 psia.
It is contemplated that the amount of catalyst use will vary depending on the particular parameters present in each.
Although applicant does not intend to be bound to or limited by any particular theory of operation, it is believed that the following reaction scheme represents the preferred operation of the present invention in which the compound of Formula I is CF 3 CF 2 CH 2 Cl:
CF 3 CF 2 CH 2 Cl→CF 3 CF═CHCl+HF
CF 3 CF═CHCl+HF→CF 3 CHFCHFCl
CF 3 CHFCHFCl→CF 3 CF═CHF+HCl
Generally, the reaction is represented as follows:
CF 3 CF 2 CH 2 Cl→CF 3 CF═CHF+HCl
For reactions in which the reactant comprises compounds of formula (IA) or (IB), including particularly ClCF 2 CF 2 CH 2 Cl and CF 3 CFClCH 2 Cl, respectively, the following reaction sequences are deemed likely:
ClCF 2 CF 2 CH 2 Cl→ClCF 2 CF═CHCl→CF 3 CF═CHCl→CF 3 CHFCHFCl→CF 3 CF═CHF
CF 3 CFClCH 2 Cl→CF 3 CF═CHCl→CF 3 CHFCHFCl→CF 3 CF═CHF
Formation of Compounds of Formula (I)
The present invention also involves in one aspect methods for forming compounds of formula (I), and most preferably CF 3 CF 2 CH 2 Cl comprising reacting tetrafluoroethylene with CH 2 FCl. The use of such methods may be advantageous because ethylene and its halogentated derivates, such as tertrafluorethylene, are relatively easy to handle, and are generally readily available in commercial quantities and/or can be easily produced from other readily available materials. In certain embodiments, therefore, the compounds of formula (I) are preferably synthesized by the catalyzed gas phase addition of CH 2 FCl and CF 2 ═CF 2 .
In certain preferred embodiments, the addition step comprises contacting, (preferably by introducing into a reactor) the CH 2 FCl with CF 2 ═CF 2 in a CH 2 FCl:CF 2 ═CF 2 mole ratio of from about 1:1 to about 200:1, and even more preferably of from about 1.5:1 to about 2:1
It is contemplated that this reaction step can be carried out in the liquid phase or in the gas phase, or a combination of liquid/gas phases, and it is further contemplated that the reaction can be carried out batch wise, continuous, or a combination of these. However, it is preferred that this reaction step comprise a gas phase reaction, preferably in the presence of catalyst, supported on carbon or unsupported, preferably a metal-based catalyst, such as antimony-based catalysts (such as SbF 3 , SbF 5 , and partially fluorinated SbCl 3 or SbCl 5 ) aluminum-based catalyst (such as AlCl 3 ), iron-based catalyst such FeCl3 including such catalysts on a carbon or other appropriate support. It is expected that many other catalysts may be used depending on the requirements of particular embodiments, and of course, two or more any of these catalysts, or other catalysts not named here, may be used in combination.
While it is contemplated that a wide variety of reaction temperatures and pressures may be used, depending on relevant factors such as the catalyst being used and the most desired reaction product, it is generally preferred that at least a portion of the addition step is carried out at a reaction temperature of from about 5 to about 1000° C., and even more preferably from about 40 to about 60° C. for reactors which are preferably maintained at a pressure of from about 1 to about 1500 psig, and even more preferably from about 20 to about 40 psig.
In certain preferred embodiments, the reactants are introduced into an appropriate reaction vessel in the form of a gas and the reactor is preferably maintained at a temperature of about 50° C. and the reactor is preferably maintained at a pressure of about 30 psig.
EXAMPLES
Additional features of the present invention are provided in the following examples, which should not be construed as limiting the claims in any way.
Example 1
This example illustrates the reaction of TFE with CH 2 FCl in a gas phase reaction. Into a ½ inch flow reactor (Monel) 50 grams of freshly prepared catalyst (as indicated below) are charged. CF 2 ═CF 2 (TFE) and CH 2 FCl (R31) are passed through a mass flow controller with a desired flow rate (as indicated below) to the preheater from respective cylinders connected with regulators. The preheater was connected to the reactor and always kept 10° C. below the reactor temperature. The reactor was uniformly heated to the desired temperature by an external heating element with an automatic control. The exit line from the reactor was connected to an on-line GC and GCMS for analysis. A 15 wt % KOH scrubber solution was used at 50° C. to neutralize acids coming out from the reactor. The gas stream coming out of the scrubber solution was then condensed in a cylinder under liquid N 2 and then finally fractionated (distilled) to isolate products. SbF 5 /C and AlCl 3 /C are used as the catalyst. At 50° C. and under 30 psig reactor pressure, 50 sccm of TFE and 150 sccm of CH 2 FCl were passed over SbF 5 /C to achieve a 26% conversion of TFE and an 82% selectivity to CF 3 CF 2 CH 2 Cl. When AlCl 3 /C is used as the catalyst, a 35% conversion and 78% selectivity to CF 3 CF 2 CH 2 Cl is obtained.
Example 2
This example illustrates the preparation of CF 3 CF 2 CH 2 Cl by reacting TFE with CH 2 FCl in a batch reactor. Thus, into a 300 ml autoclave, 0.1 mol C 2 F 4 was reacted with 0.2 mol CH 2 ClF in the presence of 0.05 mol of AlCl 3 at 20-30° for 3 hr to give 60% yield to CF 3 CF 2 CH 2 Cl which was then isolated and purified by distillation.
Example 3
This example illustrates the reaction of CTFE with CH 2 FCl in a gas phase reaction. Example 1 is repeated expect that CTFE is used in place of TFE. The major reaction products include CF 3 CFClCH 2 Cl and CF2ClCF2CH2Cl at a CTFE conversion of 21%.
Example 4
This example illustrates the reaction of CTFE with CH 2 FCl in batch reactor. Into a 300 ml autoclave, 0.1 mol C 2 F 4 was reacted with 0.2 mol CH 2 FCl in the presence of 0.05 mol of AlCl 3 at 20-30° for 3 hr to give a 60% yield of CF 3 CF 2 CH 2 Cl which was isolated and purified by distillation.
Example 5
This example illustrates the gas phase conversion of CF 3 CF 2 CH 2 C 1 to CF 3 CF═CHF. A 22-inch (½-inch diameter) Monel tube reactor is charged with 120 cc of chromium oxyfluoride catalyst. The reactor is mounted inside a heater with three zones (top, middle and bottom). The inlet of the reactor is connected to a pre-heater, which was kept at 300° C. by electrical heating. Organic is fed from a cylinder kept at 65° C. HF was introduced similarly to the pre-heater. An on-line GC and a GCMS are used to analyze samples taken at the reactor exit line at regular time intervals. The reactor effluent is introduced into a 20-60% KOH scrubber solution, and the effluent from the scrubber solution is then condensed to collect the products. The desired product, CF 3 CF═CHF, is isolated from the mixture by distillation. The conversion of CF 3 CF 2 CH 2 Cl is from about 50% to about 100% and the selectivity to CF 3 CF═CHF is from about 60% to about 100%, depending on the reaction conditions. The major byproducts were CF 3 CF═CHCl and CF3CHFCHClF.
Having thus described a few particular embodiments of the invention, various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements, as are made obvious by this disclosure, are intended to be part of this description though not expressly stated herein, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only, and not limiting. The invention is limited only as defined in the following claims and equivalents thereto.
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Disclosed is a method for producing fluorinated organic compounds, including petnafluoropropenes, which preferably comprises converting at least one compound of formula (I):
CF n X m CF a X b CH 2 X (I)
to at least one compound of formula (II)
CF 3 CF═CHF (II)
where each X is independently Cl, I or Br; n is 2 or 3; m is 0 or 1, a is 1 or 2, b is 0 or 1, m+n=3 and a+b=2.
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FIELD OF THE INVENTION
[0001] This invention relates to a platform especially suited for use supporting vehicle wheels to provide traction while traveling off-road especially through environmentally sensitive topography and to prevent unnecessary and excessive wear and damage to such off-road paths or trails. More specifically, this invention relates to a grid-type platform designed to provide all-terrain vehicles (ATVs) and four-wheel drive vehicles the necessary traction to reduce tire slippage and rutting when traveling through off-road trails or paths particularly through environmentally sensitive areas. Furthermore, this invention will minimize ecological damage, destruction and wear, for example, to wetlands, by retaining loose or saturated soil, rock, sand, etc., on the off-road trails.
BACKGROUND OF THE INVENTION
[0002] Over recent years, all-terrain vehicles (ATVs) and four-wheel drive (4WD) vehicles have become more and more popular for recreational purposes. “Off-roading” or “four-wheeling” are terms used to describe the act of driving an ATV or 4WD vehicle off a normal paved or unpaved streets. Off-roading is usually done in rural areas on trails, open fields or wooded areas. While some people use ATV or 4WD vehicles for transportation to hunting or fishing grounds, most people use them strictly for recreational purposes.
[0003] There are many state parks and private land owners which allow ATV and 4WD vehicles, usually on marked trails. One of the biggest problems faced with these off-roading trails is that because of the rather large tires and necessary engine torque inherent in such ATVs substantially deep ruts and grooves begin to form in the trails, especially in low-lying wetlands, after excessive use. Consistent wear on a trail by ATV and 4WD vehicle tires can cause irreparable ecological damage to the trail and to the local environment especially in ecologically sensitive areas such as wetlands.
[0004] The deep treaded tires found on ATV and 4WD have a damaging effect on nearly all types of surfaces. On a hard surface, such as a paved road, a tire is very efficient. An ATV or 4WD vehicle can move forward with the engine at an idle and very little power. Loose dirt on the hard surface will be compressed, but not kicked-up or displaced. On such a surface, there is minimal wear damage, however, the loose dirt on the hard surface may be displaced and eventually erode the surface until it reaches a near irreparable state.
[0005] On softer surfaces, such as a meadow, open field or wetland, the wheel and tire will typically sink into the surface under the weight of the vehicle. In these situations, the tire has to continually climb out of the depression it has created. This continuous climb requires extra power, similar to a car climbing up a hill at a similar angle to the tire climbing out of its depression. The climb out is such hard work for the tire that the lugs slip a small amount before they can compress the soil behind the lug enough to grip the surface. This slippage is constant as the vehicle moves forward. As the tire slips, plants under the tire are torn or pulled from the ground. On these surfaces, it takes as few as one vehicle to cause permanent damage to the ground, wetland and the vegetation.
[0006] No matter how slowly and carefully a vehicle is driven on soft ground, the tire always has to climb at a climb out angle and, therefore, a certain amount of slippage and resulting damage always occurs. In fact, high speed may cause less damage on softer ground because there is less time for a deeper depression to occur and thus the climb out angle would be less.
[0007] On very soft ground, such as a wetland, an open field after a heavy rain or a meadow at the base of a steep hill, the tire sinks even deeper than in the previous situation. This deeper depression increases the climb out angle and, therefore, more power is needed. As previously described, the tire must overcome the greater angle and, therefore, even greater slippage and thus more destruction results. In these situations, it is common for the tires to be slipping to the point where the dirt and plants which have been compressed will be thrown in the air behind the vehicle.
[0008] There may be situations where the ground is so soft and corresponding climb out angle is so steep that the tire spins and the vehicle comes to a halt. As the tire spins into a near vertical wall, dirt and plants are constantly thrown high into the air as the vehicle sinks deeper and deeper in the rut it has created.
[0009] Many states in the U.S. have passed laws and regulations banning ATVs and 4WD vehicles from certain parks and areas where the ecological system is too fragile to withstand the damage imposed by use of such vehicles. In some jurisdictions, it is required to use structures for minimizing such trail wear in an attempt to minimize the damage. Traction mats and vehicle support platforms are one solution to this problem.
[0010] Traction mats and vehicle support platforms, known in the art, are similar to the present invention, but with certain drawbacks. One of the largest problems with many of the traction mats known in the art is that they are very expensive to manufacture. They are typically made of a heavy material so as to withstand the weight of a vehicle without suffering from permanent deformation, however, many still become permanently warped from continued use. Another problem with previously known vehicle support platforms is their inability to easily connect with another adjacent platform. Many platforms use a pin-pinhole connection method which makes the platforms very difficult to move once it is placed on the ground. Others are not capable of interlocking or interconnecting with other platforms at all.
[0011] FIGS. 1 and 2 show two types of traction mats known in the art at the time of the invention. Viewing FIG. 1 , the traction mat is made up of certain basic structural features found in door mats used in association with entrance doors of buildings and other places to provide a convenient walking surface for catching mud, dirt or snow from a person's shoes walking thereon. These types of mats are constructed with a unvarying construction and uniform planar upper and lower surfaces.
[0012] This mat comprises a series of serpentine traction strips which may be formed from any suitable metal or high-impact plastic. Each strip has alternately opposing undulations defining corresponding alternating openings. The undulations are substantially U-shaped with leg portions that slightly diverge so that the crest portions can fit inter-digitally by projecting into the mouth ends of each opening.
[0013] The inter-digited crest portions of the undulations are articulately coupled by way of suitable hinge pin rods desirably formed from gauge wire and extending through aligned holes. To retain the rods against endwise displacement, they are provided with a locking means at their opposite ends. For support at each opposite end of the mat, reinforcing and stabilizing means, such as a closure strip bar, may be provided and which may be formed from the same strip material as the traction strips or may be of a slightly heavier gauge, if preferred. Each of the end bars is secured to the crests of the endmost undulations of the mat as by means of rivets.
[0014] Another type of traction mat, as shown in FIG. 2 , is primarily made from a plurality of parallel linear strips arranged with the sides of an elongated, generally rectangular protecting grid having a high traction top surface. A second series of parallel linear strips is positioned to the sides of the protecting grid. The grid is fitted on one side with an interlocking means adapted to fit one grid to another. This interlocking means may consist of adapting sides with a plurality of spaced apertures therein.
SUMMARY OF THE INVENTION
[0015] There is a need in the art for a vehicle support platform which can overcome the previously discussed problems. The present invention is directed at further solutions to address this need.
[0016] In accordance with one aspect of the present invention, a vehicle support platform is designed to disperse the weight of a vehicle and provide improved traction on unstable terrain surfaces.
[0017] In accordance with another aspect of the present invention, a vehicle support platform has a non-interlocking jigsaw, profile structure with congruent surface features so the sidewalls of adjacent vehicle support platforms compliment one another.
[0018] A further aspect of the present invention is to provide a vehicle support platform with a reinforced grid structure to enhance strength and minimize weight.
[0019] Yet another aspect of the present invention is providing strategically positioned cleats to the underside of the vehicle support platform to stabilize motion and to provide a retention support for the platform on the ground underneath.
[0020] The invention relates to a vehicle support platform for use in protecting off-road trails and ecologically sensitive terrain comprising a molded platform having a contiguous sidewall defining an outer edge of the platform and connecting a plurality of longitudinal and lateral intersecting support walls defining a planar top and bottom surface for supporting a vehicle thereon; a plurality of cleats depending from the bottom surface of the platform, at least one of a recess or projection formed by the sidewall in the outer edge of the molded platform; the recess or projection being sized to receive or to be received by a corresponding projection or recess in an adjacent vehicle support platform.
[0021] The invention also relates to a method of protecting off-road trails and ecologically sensitive terrain from damage from off-road vehicles, the method comprising the steps of placing a molded platform in a desired location having a contiguous sidewall defining an outer edge of the platform and connecting a plurality of longitudinal and lateral intersecting support walls defining a planar top and bottom surface for supporting a vehicle thereon; affixing the molded platform into the terrain by a plurality of cleats depending from the bottom surface of the platform; aligning the molded platform with at least a second adjacent molded platform by forming at least one of a recess or projection in the sidewall in the outer edge of the molded platform; the recess or projection being sized to receive, or to be received by a corresponding projection or recess in the second adjacent molded platform.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a top broken view of a known traction mat;
[0023] FIG. 2 is a top elevational view of another known traction mat;
[0024] FIG. 3 is a perspective view of the top surface of one embodiment of the present invention designed for use in flat terrain;
[0025] FIG. 4 is a perspective view of a bottom surface of the first embodiment of the present invention designed for use in flat terrain;
[0026] FIGS. 5A, 5B and 5 C are cross-sectional front, side and perspective elevational views of the present invention designed for use in flat terrain;
[0027] FIG. 6 is a top planar view of the top surface of the grid support of the first embodiment;
[0028] FIG. 7 is a perspective view of the top surface of a second embodiment of the present invention designed for use in sloping, hilly terrain;
[0029] FIG. 8 is a perspective view of a bottom surface of the second embodiment of the present invention designed for use in sloping hilly terrain,
[0030] FIGS. 9A, 9B and 9 C are cross-sectional front, side and perspective elevational views of the present invention designed for use in sloping, hilly terrain, and
[0031] FIG. 10 is a top planar view of the top surface of the grid support of the second embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The present invention, a vehicle support grid 1 shown in a first embodiment in FIG. 3 , is defined, in general, by a framework which is a substantially rigid, single-piece, molded grid structure. The vehicle support grid 1 is defined by a top surface 2 and a bottom surface 4 and delineated by an outer perimeter sidewall 6 . A plurality of depending cleats 8 extend from the bottom surface 4 of the grid structure in order to provide an adequate means of securing the grid structure into a desired ground surface. Preferably, the cleats 8 are integrally positioned depending from the outer perimeter sidewall 6 of the vehicle support grid 1 , however, it is possible to place the cleats 8 at any location depending from the bottom surface 4 of the platform to accommodate various terrain surfaces.
[0033] Each vehicle support grid 1 has a lateral width w and a longitudinal length L, the width w being in the range of about 30 to 60 inches, preferably about 42 inches, and the length being in the range of about 25 to 40 inches, preferably about 30 inches. The sidewall height is between about 2-5 inches and preferably about 3 inches, and the length of the depending cleats 8 between about 2 to 5 inches and preferably about 3 inches. It is important to note the right angular formation of the cleats 8 which facilitates maintaining the support grid in position once positioned on the ground. The right angular nature of the cleats 8 presents perpendicularly adjacent walls 9 and 11 to provide both lateral and longitudinal support horizontally against the ground into which the cleats 8 are placed. Such lateral and longitudinal support keeps the support grid 1 from moving horizontally or twisting once positioned in the ground.
[0034] It is to be appreciated that the lateral width w, length L, sidewall height, and cleat length may be variable to some extent, and should not be unduly limited by the above noted ranges, however, it is important that within such ranges as defined above, the vehicle support grids 1 are easily stacked, carried and placed at an appropriate trail location by hand or from an ATV vehicle itself.
[0035] The vehicle support grid 1 has a grid pattern encompassed by the outer perimeter sidewall 6 composed of intersecting longitudinal reinforcement bars 10 and lateral reinforcement bars 12 . For purposes of the following description, a longitudinal axis P is defined through the center of the vehicle support grid 1 aligned parallel with the longitudinal reinforcement bars 10 and also aligned in the general direction in which an ATV vehicle will travel over the support grid 1 . A lateral axis A is correspondingly defined through the middle of the support grid 1 , but parallel aligned with the lateral reinforcement bars 12 substantially perpendicular to vehicle travel.
[0036] The longitudinal and lateral reinforcement bars 10 , 12 intersect perpendicular with one another and are each provided with respective top edges 18 , 20 which are co-planer with one another and further define the top surface 2 , as well as bottom edges 19 , 21 also co-planar with one another and together define the bottom surface 4 of the support grid 1 as seen in FIG. 4 .
[0037] The embodiment shown in FIGS. 3-6 is generally for being positioned on relatively flat ground as opposed to a second embodiment to be discussed below for placement on a slope. In this first embodiment, the perpendicularly aligned longitudinal and lateral reinforcement bars 10 , 12 define a plurality of grid sections 24 . As seen in FIG. 6 , each grid section 24 in the present embodiment is shown substantially as square or rectangular in nature, although other shapes may be possible as well, where each side of the grid section is formed by portions of the intersecting longitudinal and lateral reinforcement bars 10 , 12 . Each grid section 24 is divided by an intermediate longitudinal reinforcement bar 26 , or web, which is aligned parallel, but spaced from the longitudinal reinforcement bars 10 forming the sides of each grid section 24 . Correspondingly, the intermediate longitudinal reinforcement bar 26 is integrally connected at a right angle with opposing sides of the grid sections 24 formed by the lateral reinforcement bars 12 .
[0038] The support grid 1 is usually placed on the ground in a position where the longitudinal axis l of the support grid 1 is aligned parallel with the direction of travel of the vehicle to be supported. In this arrangement, the wheels of the vehicle generally grip the lateral reinforcement bars 12 as the vehicle wheels travel across the support grid 1 in a manner perpendicular to the lateral axis A. The longitudinal reinforcement bars 10 provide little traction or friction to assist in moving the vehicle forward, except for providing structural support to the lateral reinforcement bars 12 and, of course, some vertical support to the vehicle wheels. However, the longitudinal reinforcement bars 10 do impede lateral slippage or sliding of the wheels by intersecting between extending portions of the tire tread, often referred to as “knobbies”. These knobby extending protrusions from the wheel are blocked or impeded from lateral movement along the lateral axis A because the knobbies are permitted by the above discussed structure of the grid sections 24 to extend below the level of the top surface 2 as defined by the top edges 18 , 20 of the longitudinal and lateral reinforcement bars 10 , 12 . This is further facilitated by the shorter intermediate longitudinal reinforcement bar 26 allowing more of the vehicle wheels and the knobby tread to fall within the grid section 24 to grip the lateral and intermediate reinforcement bars 12 and 26 .
[0039] Observing the side, cross-sectional view of FIG. 5A , the intermediate longitudinal reinforcement bar 26 in each grid section 24 has a height h less than that of the adjacent lateral reinforcement bars 12 . The intermediate longitudinal reinforcement bar 26 extends from a bottom edge 27 generally aligned co-planar with the bottom surface 4 of the support grid 1 , to a top edge 29 spaced from, i.e., lower than the top surface 2 . The intermediate longitudinal reinforcement bar 26 also connects the lateral reinforcement bars 12 forming the sides of each relative grid section. The lateral and longitudinal reinforcement bars 10 , 12 , are similar in height to the sidewall 6 , thus being in the range of about 2 to 5 inches and preferably about 3 inches. The thickness of the sidewall, reinforcement bars, intermediate reinforcement bars as well as the cleats 8 being about 0.25 to 0.5 of an inch and preferably about 0.38 of an inch. The intermediate longitudinal reinforcement bar 26 has a height h may be about one half the height of the longitudinal and lateral reinforcement bars 12 , but is generally in the range of about 1 to 2.5 inches and preferably about 2 inches. As discussed, this assists with the traction of the vehicle by allowing a certain amount of the tread and the wheel to fall below the top surface 2 of the support grid 1 as defined by the top edges 18 , 20 of the longitudinal and lateral reinforcement bars 14 , 16 . This permits more of the vehicle wheel to grip both the lateral and intermediate longitudinal reinforcement bars 10 , 26 to provide traction, as well as permit additional contact and traction with the ground surface which becomes interspersed between grid sections 24 .
[0040] It is notable that the intermediate longitudinal support 26 could also be aligned in parallel with the lateral reinforcement bars 12 , however in the preferred embodiment the intermediate longitudinal supports 26 are parallel aligned with the longitudinal reinforcement bars 10 so that the torque applied by vehicle wheels perpendicularly directly against the lateral reinforcement bars 12 is better supported. In other words, where the vehicle direction of travel is substantially along the longitudinal axis l, the torque applied by the wheels of the ATV to the support grid 1 will generally be born directly by the lateral reinforcement bars 12 where they are contacted directly by the wheel. Without support, such torque could cause the lateral reinforcement bars 12 to twist, deform or even break. With the perpendicular support of the intermediate longitudinal supports 26 in addition to the support provided by the longitudinal reinforcement bars 10 , the lateral reinforcement bars 12 are bolstered to resist the direct torque applied by vehicle wheels.
[0041] Turning to FIG. 6 , the vehicle support grid 1 is further defined by the grid sections 24 being adjacently formed in lateral rows and longitudinal columns 32 . In an advantageous aspect of the present invention, certain of these rows and columns are offset lateral rows 34 or offset longitudinal columns 36 from one another. This arrangement of offset lateral rows 34 and offset longitudinal columns 36 forms a jigsaw-like circumferential profile of the outer perimeter sidewall 6 . By offsetting a lateral row of grid sections 24 by one grid section, a profile in the sidewall 6 is created having at least a recess 40 on one side of the support grid 1 and a protruding grid square 42 defining the sidewall on the opposing side of the support grid, i.e., on the other end of the respective lateral row. Similarly, one or more offset longitudinal columns 36 of grid sections 24 could be offset from the other columns 32 so that a recess 41 is formed in one end of the support grid 1 and a protruding grid square 43 extends at the opposite end of the support grid 1 from the recess.
[0042] It is also to be appreciated that the offset rows and columns 34 , 36 do not have to be offset as described above or offset by a complete grid square 24 . It could be that certain rows and columns may define a recess 40 , 41 by providing one less grid section or a smaller grid section on the peripheral edge of the support grid 1 defining the sidewall 6 . Similarly, an additional grid section or partial grid section may compliment the end of any row or column of grid sections 24 to provide a protruding extension 42 , 43 to the sidewall 6 of the vehicle support grid 1 .
[0043] It is to be recognized that each vehicle support grid 1 has a similar jigsaw-like profile of the sidewall 6 and thus each opposing side and opposing end of each vehicle support grid 1 being respectively complimentary, so as to flexibly engage and interleave with an adjacently positioned support grid 1 . In this manner, the individual vehicle support grids 1 may be laid side by side and end-to-end and interleaved to the extent that while each vehicle support grid 1 may move independently in a vertical direction relative to one another and the ground. The support grids 1 are interleaved with the recess' 40 , 41 defined on one support grid 1 engaging the corresponding protruding grid squares 42 , 43 in the adjacent grid support sidewall 6 , so as to prevent relative planar movement and rotation between one another and to prevent lateral and longitudinal displacement relative to one another and the ground.
[0044] When the support grid 1 is placed on the ground, whether on a trail, an open field or any other natural surface, the cleats 8 will sink into the ground until the bottom surface 4 of the support grid 1 presses against the ground surface. Although the support grid 1 may continue to sink down with use and time, the top surface 2 of the platform defines the new support surface for any off-road vehicle over the terrain. Although the soft, saturated or loose ground surface upon which the support grid 1 is placed may flow or be forced up into the grid sections 24 , especially over time and use, this support grid 1 and the top surface 2 thereof, allows for a vehicle to travel along the trail, field, etc., without significantly impacting or destroying the ground underneath the support grid 1 . As several of these platforms are laid adjacent and interleaved with one another, it is possible to cover the entire length of a desired environmentally sensitive area with these platforms without significantly disturbing the ground underneath and preventing further disruption, erosion or rutting.
[0045] Lastly, in this embodiment the preferable spacing between lateral reinforcement bars 12 is about 5 to 6 inches and also about 5 to 6 inches between longitudinal reinforcement bars 10 . In this regard, the intermediate reinforcement bars are thus parallel spaced from the longitudinal reinforcement at about 2.5 to 3 inches. Such spacing can be important to the usefulness and function of the present invention in regards to ATV vehicles. If the grid sections 24 are too small, very little of the tire will be able to grip the reinforcement bars and the potential to slide off the support grid 1 and into the unprotected terrain is increased. If the grid sections 24 are to large, more radial surface are of the wheels will fall below the surface 2 of the support grid 1 and the ATV wheels will labor and thus require more torque to overcome the impediments presented by the reinforcement bars.
[0046] The jig-saw pattern of the present invention as discussed above allows for two similarly positioned adjacent support grids 1 to fit geometrically together without a secured fastening type device directly between each individual support grid 1 as shown in the previously known traction mats. Therefore, when one support grid 1 is already defining a pathway and a second support grid 1 is placed in the same direction, adjacent to the first support grid 1 , the interleaved recesses and protruding grid sections will allow for each support grid 1 to have the ability to withstand the weight of a vehicle independently without transferring the vertically induced forces to adjacent support grids 1 . However, because the jig-saw fit limits the degree of planar rotation between adjacent support grids 1 , the platforms will not twist relative to one another and the pathway created by these platforms remains intact.
[0047] In FIGS. 7-10 , a further embodiment of the vehicle support grid 1 is designed in regards to the needs of the off-road vehicle while traveling on sloped terrain. In this second embodiment in which like elements are identified by the same reference letters and numerals as in the first embodiment, a complete description of the common elements is not provided for sake of brevity. The difference in structure between this second embodiment and that previously disclosed is the alternation in the arrangement and height of certain of the longitudinal reinforcement bars 10 in order to provide better grip or traction for the vehicle wheels when traveling uphill or downhill.
[0048] This novel sloping terrain structural arrangement can be explained by understanding the increase in required torque for a vehicle traveling up or down an incline. When traveling on flat terrain, low to medium torque is sufficient to accelerate the vehicle under normal operating conditions. As the vehicle begins to ascend a slope, the necessary torque is greatly increased to compensate for the gravitational forces acting against the vehicle. Therefore, there is a much greater demand for power from the tires and hence an increase in torque to the wheels can lead to slippage between the wheels and the ground.
[0049] Observing a central portion of the vehicle support grid 1 as shown in FIG. 7 , the longitudinal reinforcement bars 10 , which define respective sides of the grid sections 24 , are lowered to be the same or similar height as the intermediate longitudinal reinforcement bars 26 . In this manner are created a plurality of adjacent intermediate longitudinal reinforcement bars 26 within elongate, rectangular shaped grid sections 25 . These rectangular shaped grid sections 25 are aligned with their longer sides defined by the lateral reinforcement bars 12 parallel with the lateral axis A to facilitate better traction of the vehicle wheels as discussed in further detail below.
[0050] In this second embodiment, these plurality of adjacent intermediate reinforcement bars 26 may have a height of between about 1 to 2.5, and more preferably about 2 inches. The remaining longitudinal and lateral reinforcement bars 10 , 12 may be generally the same height as described with respect to the first embodiment.
[0051] Similar to the first embodiment, the vehicle support grid 1 of the second embodiment is defined by the grid sections 24 and, also in this case, elongate grid sections 25 , being adjacently formed in lateral rows and longitudinal columns 32 . In an advantageous aspect of the present invention, certain of these rows and columns are offset lateral rows 34 or offset longitudinal columns 36 from one another. This arrangement of offset lateral rows 34 and longitudinal columns 32 forms a jigsaw-like circumferential profile of the outer perimeter sidewall 6 . By offsetting a lateral row of grid sections 24 by one grid section, a profile in the sidewall is created having a recess 40 on one side of the support grid, and a protruding grid square 42 defining the sidewall on the opposing side of the support grid, i.e., on the other end of the respective lateral row. Similarly, one or more longitudinal columns 32 of grid squares could be offset from the other columns so that a recess 41 is formed in one end of the support grid and a protruding grid square 43 extends at the opposite end of the support grid from the recess 41 .
[0052] It is also to be appreciated that the rows and columns do not have to be offset as described above or offset by a complete grid section. It could be that certain rows and columns may define a recess 40 , 41 by providing one less grid section or a smaller grid section on the peripheral edge of the support grid 1 defining the sidewall. Similarly, an additional grid section or partial grid section may compliment the end of any row or column of grid sections 24 to provide a protruding extension 42 , 43 to the sidewall 6 of the vehicle support grid 1 .
[0053] It is to be recognized, observing FIG. 10 , that each vehicle support grid 1 has a similar jigsaw-like profile of the sidewall 6 and thus each opposing side of each vehicle support grid 1 being respectively complimentary so as to flexibly engage and interleave with one another. In this manner, the individual vehicle support grids 1 may be laid side by side and end to end, and interleaved to the extent that while each vehicle support grid 1 may move independently in a vertical direction relative to one another and the ground, the support grids 1 are interleaved with the recess 40 defined on one support grid 1 engaging the corresponding protruding grid square 42 in the adjacent grid support sidewall 6 , so as to prevent relative planar movement and rotation between one another, and to prevent lateral and longitudinal displacement relative to one another and the ground. In general the vehicle support grids 1 of both the first and second embodiment have complimentary recesses and protruding grid sections 42 , 43 so that flat terrain sections of the support grids 1 will interleave also with the sloping terrain support grids 1 of the second embodiment.
[0054] Also, as seen in FIG. 7 the grid sections 24 making up the left and right sides, i.e., the longitudinally aligned grid sections 24 making up the left and right sides on either side of the elongate grid sections 25 may be of different sizes. For example, observing FIG. 7 , the grid sections on the right side of the support grid 1 may have a plurality of intermediate supports 26 , where the grid sections on the left side are most similar to those of the first embodiment with only one intermediate support 26 . This may facilitate better traction of a vehicle towards a center of adjacently side by side positioned support grids 1 .
[0055] Turning to FIG. 9A , by lowering the height of certain of the adjacent longitudinal reinforcement bars 26 in the sloping terrain support grid 1 of the second embodiment to create the elongate grid sections 25 , this embodiment allows for more surface area on the outer circumference of the tire to “sink in” to the platform, i.e., a larger radial portion of the wheel falls below the top surface 2 of the vehicle support grid 1 , into the elongate grid section 25 . The depth to which the radial portion of the wheel will fall is defined by the height h of the lower intermediate reinforcement bars 26 . Thus, the wheel is provided with more circumferential surface area to grip, minimizing slip and maximizing traction between the wheel and the support grid 1 . Greater traction allows the tire to more easily climb the sloped incline while also minimizing the risk of the vehicle slipping and sliding on an incline and creating damage to the trail.
[0056] Since certain changes may be made in the above described improvement, without departing from the spirit and scope of the invention herein involved, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention.
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A grid-type platform especially suited for use supporting vehicle wheels to provide traction while traveling off-road especially through environmentally sensitive topography, and to prevent unnecessary and excessive wear and damage to such off-road paths or trails. More specifically this invention relates to a grid-type platform having a plurality of grid sections defined by intersection lateral and longitudinal walls and having an intermediate support designed to provide all-terrain vehicles and four-wheel drive vehicles the necessary traction to reduce tire slippage and rutting when traveling through off-road trails or paths particularly through environmentally sensitive areas.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the production of annular parts by means of a generally flat metal sheet and whose initial shape is predetermined in order to form, once deformed, the annular part to be obtained. The invention is advantageously used when machining operations are to be carried out on said part. The invention has more particularly been developed for producing a slightly conical, front ferrule of an aircraft turbojet engine casing.
2. Description of the Prior Art
Double flow turbojet engines constitute one propulsion engine type for aircraft. Their overall shape can be likened to a cylinder having a length of several meters, the external diameter varying constantly as a function of the construction of the different parts of the engine. For example, at the coldest flow pipe surrounding the engine, the casing has a shape which widens slightly and then becomes cylindrical, before finally reassuming a conical shape in order to reduce the diameter of said coldest flow pipe. Therefore the engine casing is often constituted by a succession of annular ferrules, whose shapes have varying degrees of complication and on which numerous machining operations take place with a view to fixing the different accessories (inspection means, ducts, control means, etc.). Moreover, these machining operations frequently include the hollowing out of the ferrule in order to reduce its weight.
For example, a front ferrule of a casing at the coldest flow pipe can be constituted by a slightly conical, titanium ferrule, whose diameter can be between 500 and 1000 mm. It is often obtained from a metal sheet with a thickness close to 7 mm and which is then hollowed out by a machining operation in order to lighten the same and provide the fixing of various accessories, while still leaving ribs in order to rigidify the part. Such a part can be obtained in different ways.
One conventional method for shaping the metal sheet, which is known as "ferruling", consists of cambering or bending the sheet between several rollers positioned on either side thereof. The definitive radius of curvature is obtained by the successive passage of the sheet between these rollers. Once bent, the ferrule is terminated by welding in accordance with two generatrixes using conventional equipment. This method makes it necessary to carry out machining operations following the cambering or bending, because the pressure forces of the rollers would lead to the flattening or inclination of numerous ribs resulting from the machining. It is then necessary to machine the part following said bending operation, which is relatively difficult and expensive. Thus, the machining of a ferrule with a diameter of approximately 800 mm and having at numerous locations a thickness of 1 or 2 mm is very difficult. However, such a machining can be brought about chemically, the ferrule being immersed in a large tank provided for this purpose, but said method is very expensive and difficult to perform.
Another method used consists of carrying out bending by successive folds using a conventional folding machine. The folds are made along the generatrixes, which have a reduced inertia compared with the others. This method suffers from the disadvantage that folding marks on the ribs are left behind after said bending operation. Moreover, in this method, the metal is exposed to stresses exceeding the yield strength or modulus of elasticity of the metal.
The aim of the invention is to produce such parts by shaping the metal sheet into a ferrule after carrying out all necessary machining operations on the flat sheet, so as to avoid using chemical working or machining.
SUMMARY OF THE INVENTION
Therefore a first main object of the invention is a process for the production of an annular axis of revolution part from a flat metal sheet, whose shape is predimensioned for this purpose.
According to the invention, the process consists of progressively bending the metal sheet on winding it by a first end about the axis of revolution by means of a pressure roller, which exerts a pressure by rolling on the surface of the sheet which is to become the outer surface of the annular part, so as to join two opposite ends of the sheet to one another, while using deformation forces remaining below the yield strength of the metal from which the sheet is made and then the two joined ends are welded.
Such a bending by the progressive deformation of the sheet makes it possible to machine the latter prior to carrying out said shaping.
The process is preferably performed using internal supports for guiding the inner surface of the sheet during the deformation. Holding brackets can be placed in each case facing an inner support in order to hold the thus deformed sheet.
In order to eliminate a major part of the stresses produced by the bending operation, it is proposed that a thermal expansion treatment be carried out after welding. As a function of the materials used and more particularly in the case of titanium alloy parts, this operation can be carried out at approximately 450° to 550° C. for between 2 and 6 hours. Such an expansion heat treatment can also be followed by a thermal calibration or gauging phase.
The process according to the invention applies more particularly to the production of a ribbed, conical, titanium ferrule with shapes to be fashioned onto at least one of the surfaces of the sheet, the machining of all these shapes taking place prior to the shaping by bending of the sheet.
The second main object of the invention is a tool system for performing the process as summarized hereinbefore. It comprises a plate rotating about an axis, which is the axis of revolution of the annular part to be obtained and which is rotated by a motor and on which are mounted the inner supports fixed to a base; a first means for fixing a first end of the sheet to the rotary plate with an inclination corresponding to that of the generatrixes of the part formed; a pressure roller mounted so as to rotate about a rotation axis parallel to said inclination of the generatrixes and coplanar to the axis of the rotary plate; and second mobile means for fixing the second end to the first end of the metal sheet.
The first and second fixing means comprise a fixing block mounted in fixed manner on the rotary plate, a flange for fixing the first end to the fixing block, a mobile block, a mobile flange for fixing the second end of the sheet to the mobile block close to the first end of the sheet and screws for fixing the mobile and fixing flanges.
The rotary plate is advantageously completed by several inner supports fixed in a regulatable manner relative to the rotary plate in order to guide the inner surface of the metal sheet during bending. In this case, the tool system is advantageously completed by fixing brackets, each bracket being positioned facing an inner support, so that there is no deformation of the sheet once it has been bent.
These inner supports are preferably in the form of a semicylinder, the effective support points being constituted by the generatrix of each semicylinder furthest from the axis of the rotary plate.
In order to permit the welding on said tool system of the two opposite ends to be welded to one another, level with the junction of the two ends of the sheet, the fixing flange and the fixing block are not contiguous with the mobile flange and the mobile block, so as to leave an opening on either side of the sheet at the location of the junction of the two ends to be welded, so as to permit welding before the tool system is removed from the shaped part.
Preferably, the tool system comprises hooks fixed to the mobile flange and which are intended to be attached around the fixing flange and fixing blocks, set screws being screwed into the hooks to permit the complete moving together of the two opposite ends to be welded. In order to carry out said welding operation, the welding head can advantageously be mounted on the rotary plate mobile in translation along the junction to be welded. To permit welding, an argon circulation can be provided in the two mobile and shaping blocks.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIGS. 1A to 1F shows the production process according to the invention.
FIG. 2 illustrate the tool system according to the invention during bending of the metal sheet.
FIG. 3 shows an inner support in the form of a semicylinder and its corresponding bracket.
FIG. 4 illustrates the two fixing means for the two sheet ends.
FIG. 5 shows in section and in silhouette, the fixing of a hook used on the fixing means.
FIG. 6 shows the fitting of the mobile block to the fixing block.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
1) Process
FIGS. 1A to 1F illustrate the bending of a sheet 2 according to the invention, followed by a welding phase for said sheet.
FIG. 1A shows a metal sheet 2, whereof a first end 3 is fixed to a rotary plate 6 about a vertical axis or spindle 7. For this purpose use is made of first fixing means constituted by a fixing block 10 and a fixing flange 36. The sheet 2 is thus tangentially fixed to the rotary plate 6. A roller 4 mounted so as to rotate about a second axis 5 is placed alongside the rotary plate 6, so that its periphery is very close to the fixing block 10 of the rotary plate 6 when the latter is rotated, said roller being a pressure roller.
Thus, as shown by the curved arrow in FIG. 1B, when the rotary plate 6 is rotated about its vertical axis, the fixing block 10 of the rotary plate 6 drives the sheet 2 about the rotary plate 6. The presence of the pressure roller 4 maintains the sheet in the vicinity of the rotary plate 6 by bearing on its outer surface 2E. This starts the winding of the sheet 2, by torsion or bending, about the rotary plate 6. To guide said bending of the sheet 2, several inner supports 8 are fixed to the periphery of the rotary plate 6 in the same way as the fixing block 10. The top 9 of each inner support 8 is placed at a distance from the vertical rotation axis 7 of the rotary plate 6 equal to the radius of the part to be obtained.
If, as shown in FIG. 1C, the rotation of the plate 6 continues, the sheet 2 is rotated about said plate 6, the pressure roller 4 applying the inner surface 2I of the sheet 2 to the tops 9 of the successive inner supports 8. To assist the maintaining in place of the metal sheet 2 around the rotary plate 6, use is preferably made of holding brackets 14, each positioned facing an inner support 8. Therefore the sheet 2 is made to stay in place around the rotary plate 6 and the inner supports 8, no matter what stresses result from this deformation.
FIG. 1D shows the end of the sintering of the sheet 2 when the final inner support 8Z arrives at a position facing the pressure roller 4. The second end 1 of the metal sheet 2, or its rear end is always free. However, mobile fixing means have been previously fixed to said second end 1 of the metal sheet 2. They are constituted by a mobile block 11 and a mobile flange 12. The latter is provided with at least two hooks 13 which are attached round the flange 36 and the fixing block 10 of the rotary plate 6.
Thus, on completing the rotation of the plate 6, the free end 1 of the sheet 2 is brought into the vicinity of the first end 3 of the sheet 2 fixed to the fixing block 10 of the plate 6. A mechanism for fixing the hook 13 to the fixing flange 10 permits the anchoring of the flange 11 and the mobile block 12 on the flange 36 and the fixing block 10 of the rotary plate 6. The bending of the sheet 2 is then terminated. A locking bar 32 makes it possible to maintain said fixing action, as shown in FIG. 1E.
The second main phase of the process according to the invention consists of welding the thus joined ends 1 and 3 to one another. FIG. 1F symbolizes this welding operation by the arrow perpendicular to the sheet 2 indicating the location of the junction of the two ends 1 and 3 of the sheet 2. The shapes of the fixing elements are such that the welding operation can be performed prior to the dismantling of the thus bent sheet 2 with respect to the tool system. These shapes will be described hereinafter.
The thus shaped annular part 20 is consequently bent and welded. The initial sheet 2 has obviously been prepared and dimensioned so that, after bending, the two ends 1 and 3 face one another and permit welding.
FIGS. 1A to 1F tend to suggest that the shaped part 20 is cylindrical. However, the cylinder is only one of the numerous possible shapes which can be obtained. Thus, it is in particular possible to produce conical ferrules. In the latter case, the initial metal sheet 2 would not be rectangular when in place. Its shape must be that of a circular sector or an elongated, twisted rectangle. The latter shape can be seen in FIG. 2. The shape and position of the inner supports 8 also determine the shape of the part to be obtained.
No matter what the final shape of the part 20, the latter has undergone severe stressing during bending. The latter operation is carried out without the metal undergoing mechanical stresses exceeding its yield strength, so that the bending stresses remain within the shaped part 20. However, the latter is constantly exposed to stresses. In order to eliminate this phenomenon, which could have harmful consequences and subject the weld to high tensile forces, it is preferable for the shaped part 20 to undergo an expansion heat treatment. The latter can consist of exposing the part 20 to a temperature close to 500° C. (450° to 550° C.) for approximately 4 hours (between 2 and 6 hours), particularly in the case of titanium alloy parts.
In the case where it is wished to obtain a part having a very precise shape, i.e. with very close dimensional tolerances, it is preferable to carry out a thermal calibration or gauging after the thermal expansion treatment. This operation consists of heating the part obtained, so that its diameter increases very slightly and is then left to cool on a calibrated mold. The external diameter of the latter is the internal diameter of the part to be obtained. During cooling, the part 20 consequently retracts on the template and its internal diameter precisely corresponds to the external diameter of the template.
2) Tool System
FIG. 2 shows a tool system making it possible to perform the abovedescribed process and more particularly in such a way as to obtain a front ferrule of a double flow turbojet engine casing at the cold flow pipe. Such a ferrule is made from titanium, which is a strong metal, has a good machinability and a relatively low density compared with other metals. This ferrule is produced from a sheet with a thickness of approximately 7 mm. However, it is necessary to hollow out said sheet to make it even lighter. Thus recesses 21 are provided in such a way that ribs 22 are left on the surface of the part, so as to ensure that the latter retains an adequate rigidity. Numerous shapes are provided in such a ferrule 20. For example, two bosses 23 are shown on the ferrule 20. Therefore the ferrule 20 is a part having extra thicknesses in a frequent and irregular manner.
The initial sheet 2 is shown with a slightly twisted, elongated rectangular shape. This shape corresponds to the developed shape of the final ferrule 20. In FIG. 2, the sheet is being bent. It is possible to see brackets 14, which have already been positioned facing their corresponding inner supports 8. These supports are mounted by their respective feet 15, preferably on a base 24 of the tool system, which is mounted on the rotary plate 6 of a machine 29. Radial slots 17 permit the positioning of the tool system on the plate 6.
Keeping the sheet centered by means of brackets takes place in a more precise manner with the aid of pressure screws 18 screwed into the brackets 14.
In FIG. 2, the fixing block is covered with a fixing flange 36 traversed by at least two groups of fixing screws 37, which fix said first end 3 of the sheet with respect to the fixing block. For this purpose the sheet contains holes.
It is also possible to see the pressure roller 4 mounted around the spindle or axis 5 in a protective cap 19. The assembly of the pressure roller 4 and its cap 19 is mounted so as to be mobile in horizontal translation with respect to the machine frame 29 on which the tool system is mounted in a rotary manner. This makes it possible to adapt the position of the pressure roller 4 relative to the diameter of the part to be obtained, corresponding with the setting of the position of the inner supports 8 of the tool system on the rotary plate 6.
To the right in the drawing, the second end 1 of the sheet has been shown in its initial form, i.e. flat. Therefore the inner face 21 is still visible and will be applied to the final inner support 8Z, whose bearing semicylinder is still visible. Other elements of the tool system can be seen and will be described in greater detail hereinafter relative to the other drawings.
FIG. 3 shows in detail the brackets 14 for fixing the sheet to the inner supports 8. These brackets 14 are constituted by a metal bar terminated by a hook 28, which is positioned behind the upper portion of the inner support 8, in a notch 27. The pressure applied to the outer surface of the sheet is obtained by the screwing of several screws 18 screwed into the main portion of the bracket 14 and whose widened end acts by pressure on the sheet. The fixing of these brackets 14 to the inner supports 8 also takes place in the lower portion as a result of a notch 25 made in the lower portion of the bracket 14 and a fixing bolt 26 mounted in the foot 15 of each of the inner supports 8.
The inner supports are mounted by their feet 15 using screws 51 on the base 24. Oblong holes 50 in the feet 15 make it possible to adapt said tool system to several different diameters of the ferrules to be obtained. Thus, by varying the spacing of the inner supports 8, it is easy to increase or decrease the diameter of the part to be obtained.
It is possible to set the position of the inner supports 8 by means of an abutment 30, into which is screwed a setscrew 31 acting on the base of the foot 15 of each inner support 8.
In the described construction, the operational portion of the inner supports 8 has been shown in the form of a semicylinder 9, whose generatrix is located at the top thereof and is the part on which the sheet bears. This type of inner support only constitutes one example, other equivalent elements being conceivable and usable for producing an adequate group of supports within the metal sheet.
FIG. 4 corresponds to the phase of the process shown in FIG. 1E. The sheet is completely bent and forms a ferrule 20, the two ends 1 and 3 being engaged with one another. FIG. 4 shows in detail the fixing means for the two sheet ends 1 and 3, so that the latter are joined to one another. The fixing block is covered by the fixing flange 36 covering the first end 3. The second sheet end 1 is covered by the mobile flange 12 traversed by two other groups of fixing screws 35, which fix said second end in the fixing block.
To permit the fixing of the second end 1 to the first end 3, hooks 13 shown in FIGS. 1D and 1A are fixed to the mobile flange 12. Their shape enables them to be hooked behind the fixing block and flange 36. Once in place, they are locked in this position by a fixing bar 32, which is kept secured against the fixing flange by two bolts 33.
The fixing flange 36 and the mobile flange 12, once the two sheet ends 1 and 3 have been joined together, form a slot 34 at the bottom of which is located the junction plane of these two ends 1 and 3. This slot makes it possible to weld the two sheet ends 1 and 3 before the tool system for securing and holding the sheet is removed.
The operation of the mechanism for fixing these two ends 1 and 3 is explained by FIG. 5. It is possible to see in section therein the fixing block 10 fixed to the base and against which is placed the first sheet end 3, which is kept against it by the fixing flange 36. Just to the side thereof, but represented without hatching, are located the mobile block 11 and mobile flange 12 in which is fixed the second sheet end 1. The complete mobile block 11 has a shape complementary to that of the fixing block 10 so that it can be housed in the latter.
When the sheet has been completely bent, the mobile block 11, the mobile flange 12 and the second end 1 are approached with respect to the fixing block 10 and the fixing flange 36, as is indicated by their position shown in silhouette form, i.e. in mixed lines. Thus, the second sheet end 1 has not undergone the pressure roller bending. Consequently it does not have a tendency to curve again and pass directly against the first sheet end 3. As a result, there are difficulties in placing the hooks 13 behind the assembly formed by the block 10 and the fixing flange 36. To this end, use is made of an approach tool system constituted by bolts 33 mounted so as to pivot on the flange 36. A nut 38 pushes the locking bar 32, which has a section which can be likened to a ball joint. In order to carry out the fixing, the bolt 33 is introduced into a hole made through the hook 13. This is followed by the screwing of the nut 38, which move the hook 13 and flange 36 together. Complete screwing makes it possible to place the hook 13 behind the block 10 and the fixing flange 36 and therefore place the second sheet end 1 against the first 3.
The initial size of the sheet may not be precisely that which would be suitable for directly carrying out a welding of the two ends 1 and 3. The tool system according to the invention provides for the use of a tension screw 40 screwed into the hook 13 and which can pass beyond the latter so as to bear against the fixing block 10. Screwing down of said tension screw 40 makes it possible to tension the sheet on moving together the first 1 and second 3 sheet ends.
It is also possible to see a duct 41, which issues within the slot 34 formed by the fixing block 10 and the mobile block 11 between the two sheet ends 1 and 3. This duct 41 symbolizes a supply network for gas, preferably argon, in order to ensure a minimum gas circulation throughout the welding operation carried out when the securing tool system is still fitted to the sheet.
The same tool system for fixing the two sheet ends 1 and 3 is shown in another embodiment in FIG. 6. The latter shows the fixing block 10 in which is inserted the mobile flange. It can be seen that the fixing block 10 has a cavity 42 making it possible to define a portion of the slot, which must be placed beneath the junction point of the two ends 1 and 3. Into the cavity 42 issues several ducts 41 making it possible to supply argon during welding. It is also possible to see locking screws 43, which fix the mobile assembly to the fixng block and traverse these elements by respective holes 52 and 53.
At the upper and lower ends of the mobile flange 12 is placed another setscrew 44 for securing the position of the two sheet ends 1 and 3. Thus, the bending of the initial sheet 2, which can have relatively irregular shapes and thicknesses, may mean that the two sheet ends 1,3 are not strictly facing one another. It is then necessary to adjust the height of one of these ends relative to the other. By using setscrews 44 screwed into two positioning tabs 45 of the mobile block 11 and bearing against the fixing block 10, it is possible to carry out such an adjustment. Therefore the two ends 1,3 can be accurately positioned, as indicated by the arrows, prior to the welding process.
The operation consists of welding the two sheet ends 1 and 3 is preferably carried out when the bending and fixing tool system is still fixed to the bent sheet. The welding head is fitted to the machine or machine frame supporting the rotary plate 6. This fitting can be brought about in such a way that the welding head is mobile in translation in order to make a weld along the entire height of the sheet in order to weld the bent sheet in a single operation.
To this end and as shown in FIG. 2, the rotary plate 6 can be mounted on a support, which pivots about a vertical axis 16 so as to pivot by 90° the assembly of the rotary plate and the tool system, so as to bring the thus formed ferrule into a position where its axis of revolution is horizontal. The welding head can thus be used if it is fitted so as to be mobile in horizontal translation on the frame 29 on which the tool system is mounted.
A main advantage of the invention is that all the machining operations which have to be carried out on the ferrule in order to be able to produce complicated parts, such as the front ferrule of a double flow turbojet engine, can be carried out prior to said bending operation. Thus, the chemical machining operations used beforehand for producing shapes after the formation of the ferrule lead to bubbling in the tanks. However, the shape of a ferrule imposes the use of very large tanks, so that the process is complicated and costly.
Another advantage of the invention is that it simply requires the presence of a frame or a machine having a rotary plate.
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The process and apparatus of the invention permits the production of annular parts, such as ferrules, on which machining operations are to be carried out. The process includes the steps of bending a predimensioned metal sheet by a series of internal supports mounted on a rotary plate and by a pressure roller bearing on the outer surface of the sheet. One complete rotation of the rotary plate makes it possible to completely bend the sheet into the form of a ferrule. The second main operation includes carrying out of a welding operation on the two ends of the metal sheet. This process makes it possible to carry out any random prior machining operation on the predimensioned flat metal sheet, without the machining operations being impaired by the bending or welding operation. The process is applicable to the production of front ferrules for casings surrounding the coldest pipe of a double flow turbojet engine.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a device and method for aiding the process of loading endoluminal devices into a delivery apparatus. More particularly, the present invention is directed to a device and method to facilitate the collapse of a prosthesis.
2. Description of Prior Art
Endoluminal prostheses such as stents, stent-grafts and other related devices are used to treat vessels that have become weakened or diseased. These prostheses are used in a variety of circumstances to provide a remedy for the damaged vessels. The remedy can come in the form, for example, of added support for a vessel that has become weakened as a result of an aneurysm, or to reopen a vessel in which flow has been restricted due to diseases such as arteriosclerosis.
In order to effectively deliver a prosthesis to the problematic site in the vasculature of the patient, the prosthesis must first be placed within a delivery apparatus, generally including a restrictive sheath or catheter. For example, U.S. Pat. No. 6,096,027, incorporated by reference herein, describes a loading device to compress and load prostheses onto or into a catheter. This is accomplished by placing a stent device into a flexible sleeve or bag, and pulling the bagged stent device through a funnel shaped apparatus. At the end of the funnel taper, a catheter is positioned either to receive the stent device therein, or to accept the stent device thereon. The use of the bag or sleeve to pull the stent device through a funnel-shaped loading apparatus acts to minimize frictional forces inherent in collapsing a stent device from its full diameter, as well as avoiding the longitudinally applied forces associated with pushing a stent device through a loading mechanism.
The loading process described above can be additionally facilitated, particularly for large diameter stent and stent-grafts, by providing further methods to reduce the loading forces. Thus, it is desirable to provide devices and methods for preparing endoluminal prostheses in order to diminish frictional forces acting on the prostheses during the loading thereof into a delivery apparatus.
SUMMARY OF THE INVENTION
The present invention relates to devices and methods to facilitate the loading of a prosthesis into a delivery apparatus. More particularly, the present invention is related to devices and methods for forming alterations in the prosthesis to make collapsing of the prosthesis easier by reducing frictional forces acting thereon during the process of loading the prosthesis into a delivery apparatus. Advantageously, creation of alterations in the prosthesis enables a more compact collapse, leading to a smaller insertion profile. This is beneficial to both the physician and patient as complications inherent with the insertion of prostheses are largely reduced.
In preferred embodiments of the present invention, a device to create alterations in a prosthesis includes a grooved mandrel and a pressing comb. The grooved mandrel is preferably a tubular object made from a hard substance, such as stainless steel, with grooves running longitudinally down its length. The grooves are spaced around the circumference of the mandrel, creating two distinct diameters, one for the grooved areas and another for the non-grooved or raised areas. Such a device is also known as a “splined” mandrel to those of skill in the art. The pressing comb is preferably a long hard structure also preferably made of stainless steel, having teeth to create an alteration in a prosthesis without puncturing a layer thereof. The teeth of the comb are therefore extremely short in comparison to a conventional comb. One preferred embodiment of this device additionally includes a coupling apparatus, which not only connects the mandrel and the comb, but also coordinates their actions with respect to one another, mechanically controlling the alteration process.
In a preferred method of utilizing the above-described embodiment of the present invention, the grooved mandrel is placed into the prosthesis, preferably such that a tight fit between the two is achieved, and mounted on a receiving rack. The receiving rack is attached to the coupling apparatus, which is in turn attached to the pressing comb. When the coupling apparatus is activated (i.e., by using a pneumatic control box), the pressing comb is moved a pre-determined distance downward, making contact with the prosthesis (the underlying mandrel being positioned such that a grooved section is facing the comb), until a longitudinal set of alterations is created. The mandrel is then axially rotated until the adjacent grooved section is facing upward and another set of alterations is fashioned. This process is continued until a desired number of sets of alterations are produced.
In other preferred embodiments of the present invention, a device to create alterations in a prosthesis includes a grooved mandrel, a marking wheel and a shaft. The marking wheel can have teeth spaced around its circumference to effectuate an alteration on a prosthesis when the wheel runs along its periphery. In practice, the grooved mandrel is placed within the prosthesis and the shaft is placed through the middle of the marking wheel. The shaft is then used to move the wheel longitudinally down the outside of the prosthesis, forming alterations thereon. Of course, as in the embodiment described above, it would be advantageous to utilize a coupling apparatus to coordinate the formation of the alterations on the desired portion of the prosthesis.
These and other features and advantages of the present invention will become more apparent to those skilled in the art when taken with reference to the following more detailed description of the preferred embodiments of the invention and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a longitudinal view of a grooved mandrel of the present invention.
FIG. 2 depicts a cross-sectional view of a grooved mandrel of the present invention.
FIG. 3 depicts a close-up view of a pressed comb of the present invention acting on an esophageal stent with a grooved mandrel inserted therethrough.
FIG. 4 depicts a frontal view of a preferred embodiment of the present invention, showing a fully assembled pressed comb apparatus.
FIG. 5 depicts a side view of FIG. 4 .
FIG. 6 depicts an overhead view of FIG. 4 .
FIG. 7 depicts a marking wheel of the present invention acting on an esophageal stent.
FIG. 8 is a microphotograph of an esophageal stent-graft taken from one end, prior to collapse thereof for loading into a delivery apparatus.
FIG. 9 is a microphotograph of an esophageal stent-graft taken from one end following collapse thereof, without having first been altered according to the present invention.
FIG. 10 is a microphotograph of an esophageal stent-graft taken from one end following collapse thereof, having first been altered according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings, the present invention relates to devices and methods used to create alterations in a layer of biocompatible material covering or encapsulating a stent. The preferred biocompatible material utilized to cover and encapsulate stents for the present invention is expanded polytetrafluoroethylene (ePTFE), although a number of different materials are certainly within the scope of this invention, including polytetrafluoroethylene, polyesters, polyurethanes and other covering materials that would be, at a minimum, temporarily deformed from an alteration process such as the one described in the present invention. The term alteration as used herein means a small indentation, crease, dimple or differential density created in the surface of the ePTFE or other biocompatible material.
Referring to FIGS. 1 and 2, a grooved mandrel 10 is illustrated. Grooved mandrel 10 is tubular with two distinct diameters, which successively alternate about its circumference. This can best be seen in the cross-sectional view of FIG. 2, where each grooved section 14 set at a first diameter is immediately followed by a raised section 12 set at a second diameter. The importance of the two distinct sections 12 and 14 on the grooved mandrel 10 will be appreciated to one of skill in the art with respect to the creation of the alterations in the covered stents, described in more detail below.
FIG. 3 illustrates a close-up view of the creation of alterations 122 in the ePTFE covering 120 of an esophageal stent-graft 100 . The esophageal stent-graft 100 has a stent 110 that is encapsulated by an ePTFE covering 120 . The term encapsulated as used herein means at least one layer of biocompatible material, in this case ePTFE, covering each of the luminal and abluminal layers of the stent and adhered to one another through the walls of the stent. Ends 104 of the esophageal stent-graft 100 can be left uncovered and flared outward from a central axis of the stent 100 as shown. In a preferred embodiment of the present invention, the esophageal stent-graft 100 is mounted on the grooved mandrel 10 (see FIGS. 4-6 for more detail). Pressing comb 20 is positioned to contact the ePTFE covering 120 of the esophageal stent-graft 100 at measured equidistant intervals longitudinally along the length of the stent-graft 100 . The grooved mandrel 10 is positioned within the stent-graft 100 such that the grooves 12 of the mandrel 10 are underneath each set of alterations to be fashioned. When contact is made between teeth 24 of the pressing comb 20 and the ePTFE covering 120 at each groove 12 of the mandrel 10 , an alteration 122 is created in the ePTFE covering 120 .
The devices and methods to create alterations in biocompatible layers according to the present invention are especially advantageous to large diameter prostheses such as the esophageal stent-graft 100 illustrated herein. This is due to the presence of increased loading forces acting on a larger diameter prosthesis (compared to a smaller diameter prosthesis) when collapsing for loading into a delivery apparatus. However, it should be appreciated that the devices and methods presented herein are equally applicable to biliary stents and other small diameter covered stents as well as grafts or sheaths or other endoluminal prostheses. Moreover, the present invention can be used for purposes unrelated to implantable prostheses where alteration techniques can be used advantageously; for example, where such manipulation of the surface of a material provides increased or facilitated performance of the material or apparatus with which the material is attached or associated in some capacity.
Ideally, the alterations 122 will be created in the ePTFE covering 120 at a mid-point 112 between successive longitudinal articulations 114 in the stent 110 . The term articulation as used herein means a tip or point of a diamond shape in the stent wall. The creation of an alteration 122 at the mid-point 112 between successive longitudinal articulations 114 is accomplished through spacing of the teeth 24 of comb 20 and pre-positioning of the comb 20 prior to the creation of the alterations 122 in accordance with the articulation 114 spacing, so that the teeth 24 correspond to the mid-points 112 . When the comb 20 comes into contact with the ePTFE covering 120 , a set of alterations 122 will simultaneously be produced along a longitudinal axis of the esophageal stent-graft 100 .
Turning now to FIGS. 4-6, a preferred embodiment of the present invention is illustrated. FIG. 4 shows a front view of a pressing comb device 40 with esophageal stent-graft 100 mounted thereon. As partially shown in FIG. 3, the grooved mandrel 10 is inserted through the center of esophageal stent-graft 100 . This enables the mounting and stabilization of the esophageal stent-graft 100 for creation of alterations 122 in the ePTFE covering 120 . The mandrel 10 is coupled to a main support structure 42 by support pins 54 , which are inserted into the center of the mandrel 10 whereby the mandrel 10 with the esophageal stent-graft 100 mounted is fully rotatable. A stop disk 60 abuts one end of the esophageal stent-graft 100 to prevent the esophageal stent-graft 100 from migrating, and a detent disk 50 is coupled to the mandrel 10 via one of the pins 54 to control the rotation of the esophageal stent-graft 100 . The control of the esophageal stent-graft 100 is further accomplished through the use of a locking pin 52 , which is utilized to lock the detent disk 50 in each axial position for creation of alterations on the esophageal stent-graft 100 . The locking action of pin 52 can best be seen in FIG. 5, where an end view of the pressing comb device 40 is shown. The detent disk 50 has several pin holes 56 therein, each associated with an axial position of the esophageal stent-graft 100 where a set of alterations is desired. Certainly, depending on the prosthesis or material to be manipulated by the pressing comb device 40 , these pin holes 56 can be more or less numerous.
A linear slide 30 is mounted atop the main support 42 . The linear slide 30 is controlled mechanically to move in a vertical direction a desired predetermined distance. Pressing comb 20 is attached to the base of the linear slide 30 via screws 28 that slide into a pressing comb body 22 through a comb mounting plate 26 . The features of the pressing comb device 40 can alternatively be viewed from above in FIG. 6 . From this overhead view the esophageal stent-graft 100 can be seen more clearly. Once completely mounted on the pressing comb device 40 , the esophageal stent-graft 100 can be acted on by the pressing comb 20 , where each pass of the pressing comb 20 downward, contacting the esophageal stent-graft 100 , creates a longitudinal set of alterations 122 along the ePTFE covering 120 of the esophageal stent 100 .
Referring now to FIG. 7, an alternate preferred embodiment is depicted. In this embodiment, the alterations are created in the ePTFE covering 120 of the esophageal stent-graft 100 through the use of a marking wheel device 90 . The marking wheel device 90 includes a marking wheel 92 and a shaft 96 . The shaft 96 is positioned through the center of the marking wheel 92 for smooth and steady movement thereof. The marking wheel device 90 may have teeth around the circumference of the marking wheel 92 to produce alternating dimples in the ePTFE covering 120 . In the absence of teeth, alterations can be formed by the wheel 92 itself in the form of grooves along the length of the ePTFE covering 120 . In preferred embodiments, a coupling apparatus will be attached to the shaft 96 to ensure uniform movement and pressure of the wheel 92 along the ePTFE covering 120 .
FIGS. 2-10 are microphotographs of an esophageal stent-graft taken from one end, to illustrate the advantage provided by the alteration process of the present invention. FIG. 8 shows a covered esophageal stent-graft prior to collapse thereof for loading into a delivery apparatus. FIG. 9 is a microphotograph of an esophageal stent-graft following collapse thereof, without having first undergone alteration, while FIG. 10 is a microphotograph of an esophageal stent-graft following collapse thereof, having first been altered according to the present invention. It is apparent from the microphotographs that the covering of the altered stent-graft in FIG. 10 collapses in a much more uniform and compact manner than does the covering of the unaltered stent-graft in FIG. 9 . As stated above, this uniform and compact collapse is advantageous for a number of reasons, including providing a smaller resultant profile for the stent-graft, which leads to a reduction in complications in the delivery process.
In alternate preferred embodiments of the present invention, rather than a set of alterations being created along a longitudinal axis of a prosthesis as described above, different sets of alterations or a series of single alterations could be produced. For example, a circumferential set of alterations could be produced along a circumferential axis of the prosthesis by a disc-like device fashioned to fit around the circumference of the prosthesis. Teeth or other alteration-forming units could be on the inside of the disc-like device and the disc could contract at once or in intervals to cause alterations on the outside of the prosthesis. Similarly, the teeth on the disc-like device could be placed around the outside of the disc, similar to the marking wheel 92 in FIG. 7, and the device could be placed within the prosthesis to be expanded outward to cause alterations on the inside of the prosthesis along a circumferential axis. In addition, circumferential alterations and longitudinal alterations could be made in concert by different types of devices, or sets of alterations could be made on different axes simultaneously.
It should also be noted that while examples have been provided herein with regard to collapse of prostheses from a large to a small diameter, the scope of the present invention extends to the creation of alterations in the prosthesis to effectuate other forms of collapse as well. Thus, for example, alterations could be produced in a prosthesis to facilitate an accordion-like collapse thereof.
Finally, many modifications may be made by those having ordinary skill in the art without departing from the scope of the present invention. In particular, it should be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment details and procedures, can be accomplished without departing from the spirit and scope of the invention. The spirit and the scope of the claims should not, therefore, be limited to the description of the preferred embodiments contained herein.
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A method and method to ensure the uniform collapse and diminished loading forces of a prosthesis, the prosthesis having at least one layer of biocompatible material. The device includes a way to stabilize the prosthesis, wherein the prosthesis can be incrementally axially rotated, and a way to manipulate the layer of biocompatible material simultaneously at several distinct points along an axis of the prosthesis so that a set of alterations is formed in the biocompatible layer.
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BACKGROUND OF THE INVENTION
This invention relates to apparatus for depositing coatings on suitable substrates and, more particularly, to an improved radial flow reactor for coating semiconductor substrates utilizing laminar flow of reactant gases in a radial direction.
The invention will be described specifically with reference to use in depositing silicon-nitrogen films on silicon substrates although it should be evident that it is not limited thereto. The methods of depositing such films is described more fully and claimed in copending application of .[.Houser.]. .Iadd.Hauser .Iaddend.et al., Ser. No. 651,556 and application of .[.Levenstein.]. .Iadd.Levinstein .Iaddend.et al., Ser. No. 651,557, each filed concurrently with this application and having the same assignee as the instant application.
The reliability of semiconductor devices, particularly metal oxide insulator semiconductor device (MOS) is largely a function of the manner in which they are passivated and how the completed devices are isolated from the environment. U.S. Pat. No. 3,757,733, Reinberg, illustrates and teaches the use of an rf powered radial flow cylindrical reactor for coating a plurality of semiconductor substrates with an inorganic film by a low-temperature plasma deposition technique. One of the problems with this reactor is that the glow discharge reaction tends to occur prematurely in a portion of the chamber which is below the semiconductor substrates. This undesirable reaction tends to deplete the gases that eventually flow over the semiconductor substrates that are to be coated. This results in a somewhat nonuniform coating of the substrates. In addition, this premature reaction limits the amount of power that can be supplied by the rf source and results in films which tend to have a relatively high tensile stress and relatively low density. Both these characteristics have been found to contribute to cracking of the films.
It would be desirable to have an improved radial flow reactor in which a plasma discharge reaction occurs that is substantially limited to the area above and near the semiconductor substrates to be coated. Such an improved chamber would facilitate the formation of protective films which are both uniform in coverage and have relatively high resistance to cracking.
SUMMARY OF THE INVENTION
The present invention is directed to a radio frequency (rf) powered radial flow reactor which comprises a top plate, a bottom plate, and cylindrical side walls all connected in a sealing relationship .[.therwith.]. .Iadd.therewith .Iaddend.to define an evacuable chamber. First and second electrodes, which are both typically parallel cylindrical plate-like members, are contained within the reactor. The first electrode is electrically coupled to an rf power source, and the second electrode is electrically coupled to a reference potential which is typically ground potential. The second electrode has a central aperture therein. Heater elements are coupled to the second electrode. A first sheath or tube communicates through the bottom plate in a sealing relationship and extends through to the top surface of the second electrode so as to be in open communication with the aperture in the second electrode. The other end of the first sheath is in open communication with a vacuum pump.
A cylindrical gas shield surrounds and is closely spaced with all but the top surface of the second electrode. Input gases to the reactor are introduced into a gas ring which exits in the cavity between the gas shield and second electrode and then pass over the semiconductor substrates and are exhausted through the aperture therein.
Semiconductor substrates on which it is desired to deposit protective films are placed on a top surface of the second electrode.
When the rf source is activated and appropriate gases are introduced into the reactor chamber, a glow discharge reaction occurs in the space between the two .[.electrode.]. .Iadd.electrodes.Iaddend.. The gas shield is typically spaced from 1/8 inch to 1/4 inch from the second electrode. This limits the glow discharge reaction to essentially just the region between the two electrodes and substantially inhibits the forming thereof elsewhere in the reactor. The gas shield serves to intensify the glow discharge reaction immediately above the substrates. Thus higher rf power than would otherwise be practical can be effectively used to increase the intensity of the rf glow discharge reaction.
These and other features and advantages of the invention will be better understood from a consideration of the following description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 illustrate one embodiment of a radial flow reactor in accordance with one embodiment of the invention;
FIG. 3 illustrates a flow diagram of gases that may be used with the reactor of FIGS. 1 and 2; and
FIGS. 4, 5, 6, 7 and 8 each illustrate a separate graph which has as the abscissa axis one of the variables of a method for the deposition of films on semiconductor substrates, and as the ordinate axis corresponding characteristics of the deposited films.
DETAILED DESCRIPTION
Referring now to FIGS. 1 and 2, there is illustrated in a cross-section and a top view a cylindrical .[.readial.]. .Iadd.radial .Iaddend.flow radio frequency (rf) powered reactor 10. Reactor 10 comprises a top plate section 12, a bottom plate section 14, and cylindrical side wall 16. Side wall 16 is connected to the top and bottom of plates 12 and 14 in a sealing relationship to define an evacuable chamber 24.
A first electrode 18, which is typically a circular metallic member, is coupled to an rf source 22 through an impedance matching network 20. Electrode 18 .Iadd.is .Iaddend.illustrated as electrically isolated from top plate 12. A second electrode 26, which is typically a circular metallic member, comprises a top surface 28, which is adapted to support semiconductor substrates 30, a bottom portion 32, and an end portion 34. Heaters 36, which are typically contained with electrode 26, are utilized to heat the semiconductor substrates .[.3.]. .Iadd.30 .Iaddend.to a preselected temperature.
A gas flow shield 38 is closely spaced to electrode 26 and essentially surrounds electrode 26 except for the portion of the top surface 28 thereof on which the semiconductor substrates .[.wafers.]. 30 are placed. A bottom portion 40 of shield 38 is essentially parallel to bottom portion 32 of electrode 26. A U-shaped end portion 42 of shield 38 surrounds the end portion 34 .[.os.]. .Iadd.of .Iaddend.electrode 26.
A .[.Plurality.]. .Iadd.plurality .Iaddend.of sheaths or tubes 44 communicate with the internal portion of chamber 24 extending through the bottom plate 14 and bottom portion 40 of shield 38 in a sealing relationship. Sheaths 44 are coupled at first ends thereof to a gas ring 46 which has a plurality of essentially equally spaced small apertures 48 therethrough. Gas ring 46 exists in the cavity between the bottom portion 32 of electrode 26 and the bottom portion 44 of gas shield 38. Sheaths 44 are connected by second ends thereof to a common sheath (tube) 50 which has a control valve 52 connected in series therewith.
A .[.sheat.]. .Iadd.sheath .Iaddend.54 communicates with the interior of chamber 24 and extends through 14 and 38 in sealing relationship and contacts electrode 26. Electrode 26 has a central region generally at 56 which defines an aperture therethrough. Sheath 54 extends to this aperture and terminates at the top surface 28 of electrode 26. The other end of .[.sheth.]. .Iadd.sheath .Iaddend.54 is coupled to vacuum pumps 58 that are used to evacuate the interior of chamber 24.
The reactant gases required to coat the semiconductor substrates .[.wafers.]. 30 contained within chamber 24 are introduced into tube 50 and flow as indicated by the arrows.
An rf glow discharge reaction is caused to occur within chamber 24 between electrodes 18 and 26 when the rf source 22 is activated and appropriate gases are introduced into chamber 24 through 50. Gas shield 38 is typically spaced 1/4 .Iadd.inch .Iaddend.or less from electrode 26. This close spacing substantially inhibits the glow discharge reaction which occurs between electrode 18 and the top surface 28 of electrode 26 from occurring around end portion 34 and bottom portion 32 of electrode 26. This serves to intensify the rf glow discharge reaction immediately above semiconductor substrates 30. In addition, the gas shield 38 permits the effective use of higher input rf power than is possible without the shield. Without shield 38 there is a tendency for the gases introduced into the chamber 24 to react below electrode 26 and therefore to dissipate before reaching semiconductor substrates 30. Thus, without the shield 38 the increasing of rf power beyond a certain point is not particularly helpful in intensifying the glow discharge reaction above the substrates 30 where it is important that the reaction occur.
The vacuum pumps of FIG. 1 are selected to be compatible with a high gas flow rate of approximately 2 liters .Iadd.per .Iaddend.minute .[.minutes.]. at greater than 1 mm pressure. A 150 cfm Leybold-Heraeus roots blower backed with two 17 cfm mechanical pumps running in parallel were found to be sufficient to achieve the needed high gas flow rate. Additional pumping capacity comprising a cryopanel and a 400 l/s vacuum pump located below an isolation valve (not illustrated) in the reactor 10 of FIGS. 1 and 2 is utilized to initially pump the reactor 10 and 100 to a base pressure of ˜10 -6 mm.
In operation, semiconductor substrates 30 are loaded on support surface 28. The reactor 10 is then sealed, closed, and pumped down to 10 -6 mm. The heaters connected or part of the electrodes 26 are turned on and the semiconductor substrates are heated to approximately 275° C. The .[.vacion.]. .Iadd.Vacion .Iaddend.isolation valve is closed and reactant gases are admitted to the reactor and the roots blower valve is opened again. A dynamic pressure of approximately 600μ is established in the reactor with the input gases flowing at the desired flow rates. Thereafter the roots blower valve is throttled to the desired pressure. The rf power source is now activated to the desired power level.
A fully functional reactor very similar to the reactor 10 of FIG. 1 was constructed with sections 12, 14 and 16 all being stainless steel and electrode 18 being aluminum. Two tubes 44 are utilized and the gas ring utilized is a tubular member having a diameter of 5 inches. The spacing between the U-shaped section 42 of gas shield 38 and the end portion 34 of electrode 26 is approximately 1/4 .Iadd.inch.Iaddend.. The spacing between the top surface 28 of electrode 26 and electrode 18 is approximately 1 .Iadd.inch.Iaddend..
Another fully functional reactor similar to that of reactor 10 of FIG. 1 was constructed with sections 12 and 14 made of aluminum and sidewalls 16 made of pyrex. Since section 12 is electrically isolated from sections 14 and 16, it is not necessary that the electrical connection from the impedance matching network 20 to electrode 18 be electrically isolated from top plate section 12. In this reactor the gas ring is a cylindrical member having a diameter of approximately 14 inches. There are approximately 120 gas outlet apertures of 40 mils each in diameter equally spaced around this gas ring. The spacing between the end portion 34 of electrode 26 and the U-shaped portion 42 of gas shield 38 is approximately 1/8 of an inch. The distance between surface 28 .Iadd.of .Iaddend.electrode 26 and electrode 18 is approximately 1 inch.
Referring now to FIG. 3, there is illustrated a flow diagram of reactant gases that may be used in the reactor of FIGS. 1 and 2. Sources of silane (SiH 4 ) in a carrier gas argon (Ar) 1000, ammonia (NH 3 ) in a carrier gas argon (Ar) 1100, carbon tetrafluoride (CF 4 ) 1200, and oxygen .[.(o 2 ).]. .Iadd.(O 2 ) .Iaddend.are connected through a separate one of valves 1400, 1500, 1600 and 1700, respectively, to separate flow meters 1800, 1900, 2000 and 2100, respectively, and then through separate leak valves 2200, 2300, 2400, and 2500, respectively. The outputs of leak valves 2400 and 2500 are both connected through a valve 2900 to a reaction chamber 2700. Reaction chamber 2700 can be the chamber 24 of FIGS. 1 and 2. The outputs of leak valves 2200 and 2300 are both connected to mixing chamber 2600. Mixing chamber 2600 is in communiction with reaction chamber 2700 through valve 2800.
The reactant gases SiH 4 and NH 3 mix in the mixing chamber 2600 and then pass through valve 2800 into reaction chamber 2700. During the time of depositing inorganic films on semiconductor substrates, valves 1600, 1700, 2400, 2500 and 2900 are closed and valves 1400, 1500, 2200, 2300 and 2800 are open.
After one or more deposition runs, inorganic films form on the electrodes 18 and 26 and on other areas in the reactor of FIGS. 1 and 2. To clean off the films, the heaters and rf source of FIG. 1 are turned on and valves 1600, 1700, 2400, 2500 and 2900 are all opened, and valves 1400, 1500, 2200, 2300 and 2800 are all closed. The films deposited on internal parts of the reactor are cleaned by the resulting rf glow discharge reaction (the reactant gases being CF 4 and O 2 ) and a new set of semiconductor substrates can then be placed in the reactor for deposition of protective films thereon.
Advantageously all interconnecting tubing connecting the sources of gases illustrated in FIG. 3 to the reactor of FIGS. 1 and 2 are made of stainless steel to insure these connections are essentially leak-free. This essentially prevents any but the desired gases from entering the systems during the deposition operations. Essentially pure sources of SiH 4 , NH 3 , and Ar could be easily substituted for the SiH 4 in Ar and NH 3 in Ar sources.
In the first set of operating conditions described below the reactor was essentially as illustrated in FIGS. 1 and 2 without the gas shield and with electrode 18 in electrical contact with top plate 12. Side wall 16 is pyrex in this case. The following operating conditions were utilized to deposit protective films having the denoted characteristics on semiconductor substrates;
______________________________________ 1st Operating Condition 2nd Operating (using apparatus Condition of FIGS. 1 & 2 (using apparatus without gas shield) of FIGS. 1 & 2)______________________________________Reactant gas SiH.sub.4 /NH.sub.3 /Ar SiH.sub.4 /NH.sub.3 /ArSiH.sub.4 1.25% 1.70%NH.sub.3 1.56% 2.39%Ar 97.19% 95.91%Total gas 2000 2320flow (SCCM)Pressure in 1000 950reactor (μ)Substrate 330 deg. C. 275 deg. C.temperature(degrees C.)Tuned RF 60 250power (watts)(reflected power = ˜ 0)Thickness 1.1 1.1of depositedlayer (μ)Stress in 1-2 (tension) 1-5 (tension)resulting layer(10.sup.9 dynes/cm.sup.2)Etch rate in 175 180BHF (Angstromsper min.)Density (GCM.sup.-3) 2.4 2.55Composition of 1.1 1.05resultinglayer (Si/N)Refractive Index 2.15 2.05Cracking 400 450resistance(deg. C. to whichsubstrates withdeposited layerscould be raisedwithout cracking)Adhesion of Good Gooddeposited layerStep Coverage of Very good Very gooddeposited layerScratch resistance Good GoodDielectric constant 6.9 6.4Breakdown strength 3.4 3.9(10.sup.6 V/cm)Resistivity at 5 × 10.sup.18 4 × 10.sup. 132 × 10.sup.6 V/cm(ohm/cm)______________________________________ 3rd Operating 4th Operating Condition Condition (using apparatus (using apparatus of FIGS. 1 & 2) of FIGS. 1 & 2)______________________________________Reactant gas SiH.sub.4 /NH.sub.3 /Ar SiH.sub.4 /NH.sub.3 /ArSiH.sub.4 1.78% 1.78%NH.sub.3 2.25% 2.25%Ar 95.97% 95.97%Total gas 2320 2320flow (SCCM)Pressure in 950 950reactor (μ)Substrate 275 deg. C. 275 deg. C.temperature(degrees C.)Tuned RF 300 400power (watts)(reflected power = ˜ O)Thickness (μ) 1.1 1.1Stress in 1-2 (compression) 1-2resulting layer (compression)(10.sup.9 dynes/cm.sup.2)Etch rate in 125 75BHF (Ang-stroms per min)Density (GCM.sup.- 3) 2.75 2.90Composition of 0.8 0.75resultinglayer (Si/N)Refractive Index 2.00 1.94Cracking 550 550resistance(deg. C. towhich substrateswith depositedlayers could beraised withoutcracking)Adhesion of Good GooddepositedlayerStep Coverage Very good Very goodof depositedlayerScratch Good GoodresistanceDielectric 6.8 5.8constantBreakdown 5.0 8.1strength(10.sup.6 V/cm)Resistivity 3 × 10.sup.15 5 × 10.sup.19at 2 × 10.sup. 6 V/cm(ohm/cm)______________________________________
The tuned rf power indicated for each of the above operating conditions was read from a meter on the rf power supply. It is to be appreciated that the effective rf input power density between the electrodes of a reactor is a function of the geometry of the electrodes and the spacing therebetween. The reactors utilized with the above operating conditions have a circular top electrode having a .[.radius.]. .Iadd.diameter .Iaddend.of 14 inches. Electrode 18 was separated from the electrode 26 by approximately 1 .Iadd.inch.Iaddend.. A reactor with different type .[.of.]. .Iadd.or .Iaddend.size of electrodes and different spacing between .[.electrode.]. .Iadd.electrodes .Iaddend.would require an appropriately different input rf power in order to produce films on semiconductor substrates with essentially the same characteristics as described herein.
The first operating condition is useful for depositing protective films on semiconductor substrates which utilize aluminum metallization. The aluminum metallization can easily withstand temperatures at and above the 330° C. used. The second through fourth operating conditions can be used with semiconductor substrates which have aluminum or gold with titanium, palladium and gold beam leads since the temperature utilized is below that at which titanium and palladium and gold interact.
Cracking of the protective films allows moisture and inpurities (i.e., sodium) to attack the surface of the semiconductor substrates and thereby destroy the circuitry contained thereon. It is therefore very important that protective films be as crack-resistant as possible.
The fourth operating condition results in films which are substantially stoichiometric silicon nitride (Si 3 N 4 ) and which contain essentially no other organic combinations or argon incorporation. The physical characteristic of the resulting Si 3 N 4 film are superior to Si 3 N 4 films produced by chemical vapor deposition (CVD) processes in that they are much less susceptible to cracking than the CVD produced Si 3 N 4 . The reason for this is that the silicon nitride films resulting from operating condition four have relatively low compressive stress and not the relatively high tensile stress of the CVD produced films.
It is important to note that in all of applicants' operating conditions careful precautions were taken to limit the presence of nitrogen (N 2 ) or oxygen (O 2 ) in the reactor during the glow discharge reactions, it has been determined through experimentation that the addition of even small amounts of N 2 (up to 2%) or O 2 (up to 0.2%) in the reactant gas mixture can significantly adversely affect the characteristics of the resulting films. The addition of only 2% nitrogen to the reactant gases resulted in an order of magnitude increase in tensile stress of the resulting film, and an increase in the BHF etch rate of over 7 times. The addition of only 0.2%, O 2 to the reactant gases resulted in a 7-times increase in the BHF etch rate.
Using the second operating conditions as a standard, the effects of varying the five main process parameters, namely, (A) Gas pressure, (B) Total gas flow, (C) Pressure, (D) Substrate temperature and (E) RF input power into the reactor, were studied. The graphs illustrated in FIGS. 4, 5, 6, 7 and 8 each illustrate on the abscissa one of the variables denoted above, and on the respective ordinate axis some of the resulting characteristics of the film deposited on semiconductor substrates.
A. Gas Composition
The graph of FIG. 4 illustrates the effect of increasing SiH 4 concentration (1.4≦% SiH 4 ≦1.9; 0.5≦SiH 4 /NH 3 ≦0.9) in the reacting gases. These gas compositions were achieved by adjusting the flowmeters for 3%SiH 4 -Ar and 5%NH 3 -Ar to various complementary settings so as to keep the total flow constant.
As expected, increasing the SiH 4 concentration in the gas led to a corresponding linear increase in the Si/N ratio in the film (from ˜1.0 to ˜1.2), and a linear increase in the refractive index (from ˜1.9 to ˜2.2). For the lowest SiH 4 concentration used, (SiH 4 /NH 3 =0.52), the film density was found to be relatively low (˜2.3 .[.gcm-116 3 .]. .Iadd.gcm -3 .Iaddend.), and the BHF etch-rate was .[.corresponding.]. .Iadd.correspondingly .Iaddend.high (250 angstroms/min.). With increasing SiH 4 /NH 3 ratio, the film density ρ showed a broad peak (ρ≈2.55 gcm -3 ) for 0.58≦SiH 4 /NH 3 ≦0.79. The ρ decreased again at SiH 4 /NH 3 ˜0.9; however, this was not accompanied by corresponding increase in BHF etch-rate, presumably because the films now had a much higher Si content (Si/N˜1.2). The film σ, which was always tensile, showed a peak at SiH 4 /NH 3 ˜0.6, which is located at a slightly lower SiH 4 concentration than that for the peak in ρ.Iadd...Iaddend.
While most of our work has involved operating conditions in which the ratio of silane to ammonia was between 0.5 and 0.9, which is believed the preferred range, it may be feasible to deposit useful protective films with ratios outside this range.
B. Gas Flow
The graph of FIG. 5 illustrates the effect of increasing the total gas flow on the other variables of the process. The total gas flow was varied in the range 1.0 to 2.5 liters min -1 , with the SiH 4 /NH 3 ratio constant at 0.71(%SiH 4 = 1 .70). It may be seen from FIG. 5 that increasing the flow led to a higher deposition rate (from 120 to 200 angstroms/min.Iadd.).Iaddend., a greater refractive index, and a larger Si/N ratio in the film (from 0.8 to 1.05). For this range of film composition, the film density seems to have a dominant effect on the BHF etch rate; a broad maximum in ρ corresponds to a broad minimum in the etch rate. The tensile stress .[.descreases.]. .Iadd.decreases .Iaddend.with increasing flow; this is probably the result of a higher film purity (with respect to possible nitrogen/oxygen contamination) as the flow is increased.
C. Pressure
The graph of FIG. 6 illustrates the effect of increasing pressure on the other variables of the process. The average pressure during film deposition was varied from ˜700 to 1000μ (±25μ). As shown in FIG. 6, increasing the pressure also led to a higher deposition rate, whereas the density and the BHF etch rate did not change much. The refractive index decreased linearly This generally (i.e., for pressures ≧750μ) correlates with a decrease in the Si/N ratio in the film.
D. Substrate Temperature
The graph of FIG. 7 illustrates the effects of varying the temperature of the semiconductor substrates on the other variables of the process. The limited range of substrate temperatures studied (200°≦T s ≦.Badd..[.300°".]..Baddend. .Iadd.300° .Iaddend.C.) was influenced by the desire to stay below temperatures at which Pd-Au interdiffusion (in Ti/Pd/Au metallization) becomes excessive. As shown in FIG. 7, T s (substrate temperature) has a pronounced effect on the BHF etch rate, which decreases almost exponentially with increasing T s . The decrease in BHF etch-rate is associated with a linear increase in the film density, ρ and in the refractive index, n. Thus, for films deposited at 200° C. the BHF etch rate was 700 angstroms/min, the density was ˜2.3 gcm -3 and the refractive index was ˜1.85. Interestingly, these films also had a rather large Si/N ratio (˜1.2) and a high tensile stress (7×10 9 dynes cm -2 ). With increasing T s , both σ and the Si/N ratio in the film displayed a shallow minimum at ˜250° C.; however, a higher T s of 275° C. was preferred because it led to films with yet greater density (2.55 gcm -3 ) and somewhat lower etch-rate without an excessive increase in σ.
E. RF Input Power
The graph of FIG. 8 illustrates the effect of increasing the rf input power. Tuned rf input powers were investigated in the range of 100 to 350 watts (reflected power=0). For this series of experiments, the SiH 4 /NH 3 ratio was kept constant at 0.8, and SiH 4 at 1.81. For increasing rf power, there was found to be a rapid and linear increase in the film ρ (weight-gain measurement.[...]..Iadd., .Iaddend.using .Iadd.1.Iaddend.μ thick films) from 2.2 gcm -3 at 100 watts to 2.8 gcm -3 at 350 watts. Films (1μ) thick with lower density had a distinct yellowish tinge to them when deposited on Al-metallized devices, whereas those with densities ≧2.4 gcm -3 appeared to be grayish and more truly transparent. Both the film .[.ρ.]. .Iadd.σ .Iaddend.and BHF etch-rate showed a bimodal behavior at ˜275 watts. Below this power level the stresses were very low tensile (˜0.5×10 9 dynes cm -2 ) and the etch-rates were relatively high (275 to 325 angstroms/min). At rf powers ≧300 watts, the stresses, which had been tensile, became compressive (1-2×10 9 dynes cm -2 ) and the BHF etch rates were relatively low (<150 angstroms/min). Significantly, the refractive index showed a decrease with increasing rf power. The refractive index, film composition, and film density have been correlated using the Lorentz-Lorentz equation.
Finally, it should be understood that the specific embodiment of the invention described is merely illustrative of the general principles and various modifications thereof are feasible, including change in dimensions, geometry, and materials. Moreover, it should be evident that other gases may be utilized to form films of other materials.
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An improved radio frequency (rf) powered radial flow cylindrical reactor utilizes a gas shield which substantially limits the glow plasma discharge reaction to a section of the reactor over the semiconductor substrates which are to be coated. The gas shield permits the use of higher rf input power which contributes to the formation of protective films that have desirable physical and electrical characteristics.
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BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for the preparing or reconditioning the surface of snow skiing courses, or runs, of ski slopes.
The original way of preparing ski runs surfaces consisted of pressing new snow flat by means of rollers. This approach is still used today when sufficient new snow has fallen.
More and more, however, it is necessary to recondition the surfaces of ski runs which have been worn by intensive use. At present, the demand for resurfacing of worn ski runs is about equal to the demand for initial conditioning of runs that have been newly snowed over. This resurfacing is necessary because intensive use of the ski run results at certain locations, particularly on steep run sections, in the formation of an uneven, wavey surfaces having rises and dips. Such a surface requires the less expert skiers to slow down and to execute strenuous avoidance maneuvers.
There is already known a type of apparatus for evening out the irregularities of such uneven ski run sections. One such apparatus includes a driveable chassis provided with a horizontal beam extending the full width of the chassis and carrying a continuous scraper blade at its leading edge. Another has an upright blade provided at the bottom edge with a number of teeth extending to loosen the hard-packed snow of the rises.
The disadvantage of such continuous wide scrapers lies in that they extend over too wide an area to effectively level the relatively small rises. In the course of their forward movement, some portion of the scrapes is likely to strike a rise which raises the scraper at that point and thereby changes the level of the blade along its entire length to prevent it from evenly biting to the desired depth. The result is that other rises at that location are only scraped superficially. The snow thus scraped off settles in the dips between the rises and remains there, usually in the form of hard clumps which are difficult to ski over. It is therefore necessary to work these areas with a further apparatus to loosen and break up the clods and then to pack them down with a roller.
There have been attempts to remedy the disadvantages of these wide scrapers by mounting a number of relatively short scrapers on a frame so that their blades are substantially horizontal and extend in a line across the width. The blades of the scrapers are attached to arms which pivot vertically to permit them to follow the contour of the run surface. A number of relatively wide runners glide side by side in a row in front of the blades. The height of the runners relative to the frame is adjustable. The frame, which is supported in the front on the runners and in the rear on the scraper arms, thus changes its attitude to the surface when the height of the runners is changed. The change in attitude of the frame then results in a change in the pitch of the scraper blades.
It has proved in practice that even this last-described apparatus has major shortcomings. As the runners follow a raised contour, the forward portion of the apparatus becomes raised, thereby changing the pitch of the scraper blades and preventing them from biting in to a sufficient depth. Furthermore, such apparatus likewise leaves the area covered with loose clumps which must again be worked with a further apparatus. So, similar problems arise here also.
SUMMARY OF THE INVENTION
The novel apparatus in accordance with the present invention features a plurality of scrapers arranged side by side and pivoted vertically about an axis which is adjustable in height. The scrapers are disposed in front of rollers for packing down the snow.
The novel apparatus levels a ski run which has developed an uneven surface, breaks up the scraped off clumps, and packs down the material thus loosened in such a way as to form once more a suitably smooth surface.
With this arrangement, the effectiveness of the scrapers is not significantly influenced by the surface contour, and the scrapers can therefore cut deeply into even the higher rises. This results in a substantially even layer of loose snow which can be readily packed down evenly by the rollers which follow, so that the area worked by the apparatus is once again restored to a smooth ski run.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of an apparatus in accordance with a preferred embodiment of the present invention.
FIG. 2 is a side sectional view of the apparatus of FIG. 1 taken along the section line II--II.
FIG. 3 is a perspective view of the main frame of the apparatus of FIG. 1.
FIG. 4 is a partially schematic illustration showing adjustment of the pitch of the scraper blades of the apparatus of FIG. 1.
FIG. 5 is a partially sectioned view of a fragment of the apparatus of FIG. 1 illustrating a linkage between two sub-frames of the apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the present invention is the ski run resurfacing machine shown in the FIG. 1 of the drawings. The machine is suited for connection to a motorized ski run maintenance tractor, such as for example those generally used for towing compacting rollers. For this purpose there is provided a draw bar 1. This is connected to a horizontally oriented main frame 3 by means of a horizontal pivot joint 2, so that the angle between the main frame 3 and the draw bar 1 can be controlled, as will be later described. The main frame 3 is supported at the rear in an indirect fashion on two rollers 4 in a manner which likewise will be described later.
As may be seen from the FIG. 3, the main frame 3 has a front crossmember 31 with a gudgeon plate 32 in the middle for a gudgeon pin 2. A vertical post 33 is threaded to the projection 32. At the rear is a nearly portal-shaped rear cross member 34 and two struts 35 in the form of strong tubes which extend from the upper end 33a of the post 33 diagonally and slanting downward to the free ends of the rear cross member 34. By this arrangement, the frame 3 is made sufficiently resistant to torsion to be substantially unaffected by the degrees of torsion to which it is likely to be exposed in use. The front cross member 31 and ends of the rear cross member 34 each carry two horizontal trunnion studs 5, the axes of which are parallel to the towing direction of the machine and which extend towards the rear from their respective cross members. The central axis of each strut 35 intersects the central axis of the rear studs exactly in the center of the ends 36, so that the least possible bending moments are transmitted.
Two sub-frames 6a, 6b are mounted on the studs 5. In this manner each of the sub-frames 6a, 6b is so arranged that it can tilt at its front or rear stud 5 precisely about its longitudinal axis. Each sub-frame 6a, 6b carries a number of scrapers 7 and one of the rollers 4 and likewise features a front cross member 61, two longitudinal supports 62, 63, and a rear cross member 64 which is spaced some distance from the rear end of the longitudinal supports 62 and connects them together. Scraper blades 70 are mounted in front of the rollers 4 by means of plates 8 attached to pivot arms 9 which pivot vertically about a horizontal scraper trunnion 10, each trunnion being attached to the front cross member 61. The trunnions 10 are formed at the rear side of the front cross member 61 by suitable plates 11. Each scraper blade 70 is pivotable independently of the other scraper blades 70. As may be seen from the FIG. 2, the scraper blades 70 are welded to the plates 8, and the latter fastened to the pivot arm 9 by means of a shear pin 12a and a bolt 12b which serves as a pivot whenever the shear pin is sheared. On the lower side, the scraper blades 70 carry a curved sheet metal runner 71 which permits a backward motion of the machine after work with it has been completed without causing the scrapers 7 to dig into the surface. These runners 71 also provide a certain amount of control for the scrapers 7 in the towing direction, in that they prevent the scrapers 7 from digging too deeply into the surface.
The arrangement of the scrapers 7 in front of the rollers 4 is of particular significance. In contrast to the functioning of prior resurfacing machines, the surface contour is here no longer followed directly in the front, but rather the scraper blades 70 present a particular pitch to the over all surface. As may be seen from the FIG. 4, the action of the scrapers 7 depends upon this pitch. The higher the cross member 61 of the sub-frames 6a, 6b is raised from the surface (it being roughly at the same height as is the cross member 31 of the main frame), the steeper is the slant of the pivot arms 9 and the less pitch the scraper blades 70 have relative to the surface. How the pitch may be adjusted to a new setting will be described in the following.
For adjusting the scraper blade 70 pitch, there is provided on the draw bar 1 a hydraulic cylinder unit 13. It is pivotably mounted there by means of gudgeon plates 14 and pivotable about a gudgeon pin 15. Its piston rod 16 connects pivotably to a further gudgeon pin 17 through gudgeon plates 18 which extend from the upper end 33a of the post 33. If the piston rod 16 is now extended, then the distance between the pivots 15 and 17 becomes greater. Since the draw bar 1, however, is fastened to the tractor and cannot move down, the distance between the pivots 15, 17 can become greater only by the raising up of the post 33, and with it the cross member 31. The angle between the draw bar 1 and the main frame 3 is thereby made smaller. That is, the draw bar 1 is at more of a slant to the main frame 3. With the lifting of the main frame 3, and therewith of the two cross members 61, 62, the pivot arms 9 are also dropped into a steeper position. As was mentioned before, this results in a reduced pitch of the scraper blades 70. If, in reverse procedure, the piston rod 16 is drawn back, then the post 33 of the connected draw bar 1 moves down, the pivot arms 9 are given a less steep position, and therefore, the pitch of the scraper blades 70 is increased. When the machine is drawn forward, there are superimposed upon this basic setting of the scraper blades 70 the movements which each of the individual scrapers makes independently of the movements of the other scrapers by reason of the local uneven contours. The choice of pitch for the scraper blades 70 is determined for the most part by the degree of unevenness of the surface, and also by the condition of the snow.
It is noted as a significant advantage that the pivot arms 9 are fastened immediately adjacent that portion of the machine which undergoes the maximum raising and lowering in response to the height adjustment mechanism. This maximizes the degree of adjustment possible for the scraper blades 70.
As was previously mentioned, the sub-frames 6a, 6b are mounted on the main frame 3 so that they can pivot. However, they should not have the capability of pivoting independently of one another, for it could occur in working across a run that each subframe 6a, 6b and its roller 4 would work separate paths lying on different planes and separated by a shoulder. In order to prevent this, there is provided a linkage member 20 which will be described in the following discussion in relation to FIG. 5.
The linkage member 20 consists of a carriage block 21 about a guide rail 22 which is attached to the rear cross member 34 and extends downward there, as can be seen also from FIG. 3. Inside of each narrow end of the carriage block 21 is a ball bearing 23 which rides against the guide rail 22. A trunnion stud 24 extends outward from the midpoint of each of the longer sides of the carriage block 21. These studs 24 are for fastening two linkage struts 25, 26 on each side, with the other ends of the struts 25, 26 being connected to further trunnion studs on the sub-frames 6a, 6b, so that each sub-frame 6a, 6b is connected by two struts 25, 26 with the carriage block 21. If, for example, as seen facing forward the sub-frame 6a should tilt toward its right side, as a result of its left side running over a snow clump scraped up by the scrapers 7, then it will pull the carriage block 21 down by means of its struts 25. Through the action of the struts 26, this will bring about a tilting of the other sub-frame 6b in the opposite direction of rotation. It can occur that the other sub-frame 6b offers a large resistance to this tilting because its roller 4 lies flat on the surface along its entire width. This has the effect of reducing the tendency of the sub-frame 6a to tilt, with the result that the roller 4 of sub-frame 6a presses on the snow clods with a significantly greater force than is attributable to just its own weight. In this way the snow clods are reliably crushed, so that there results a suitably smooth ski run surface which may be immediately used. It is even better to permit the crushed and compacted material, which as described results from the scraped rises, to lie overnight before use. The run will then on the following day be in particularly favorable condition.
The present machine is intended primarily for downhill ski runs. However, since each of the sub-frames 6a, 6b has all the elements necessary for the surface conditioning, at least one of the sub-frames may be provided with means for using it alone. These means may be, for example, two threaded holes 28 in the upper side of the front cross-member 61. The vertical post 33, which is welded to a base plate 33b fastened to the cross member 31 with bolts is removed therefrom and bolted to the cross member 61. There are also provided two gudgeon plates 62' to permit the fastening thereto of a drawbar such as the drawbar 1, but without the reinforcement struts 41. After connection of the drawbar, it is necessary only to mount the piston-cylinder unit 13. With that, the width of the machine is reduced to one-half, so that it may now be used to condition relatively narrow ski touring and mountaineering trails, which then are sufficiently conditioned that they need only to be again reestablished.
The rear cross member 34 of the main frame 3 also serves to hold a pivoted pair of curved arms 50 which draw a smaller roller 51. These arms 50 are attached to gudgeon plates 52 on the cross-member 34 so that they pivot vertically. The roller 51 acts on the strip between the two large rollers 4 which is not contacted by them. In contrast to the rollers 4, which have numerous rows of ribs 53, the middle roller 51 has only a single row of ribs 54.
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The disclosed apparatus is a machine of the type for connection to a snow skiing course maintenance tractor. It has freely-rolling rollers for compacting the snow and a plurality of scrapers arranged side by side. The scrapers are pivoted vertically about an axis which is adjustable in height. The scrapers are arranged in front of the rollers.
Also disclosed is such a machine with combinations of scrapers and rollers arranged on side by side sub-frames which are connected together by a linkage. When one of the sub-frames is tilted in one direction, the other sub-frame is caused by the linkage to tip in the opposite direction. Means are disclosed for utilizing only one of the sub-frames alone.
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This application is a continuation of U.S. patent application Ser. No. 07/836,654, filed Feb. 18, 1992, now abandoned.
BACKGROUND TO THE INVENTION
The present invention relates to a transfer adaptor for effecting fluid communication between a vial and another container. The invention is especially, but not exclusively, suited to use in the reconstitution of injectable preparations.
It is common practice in hospitals to reconstitute injectable preparations provided in septum-sealed vials by piercing the septum with a wide bore needle and introducing sterile water or other appropriate liquid from a syringe attached to the latter. The sterile water is first drawn into the syringe from a sterile-sealed ampoule. The wide bore needles and ampoules are disposed of after use, which is wasteful.
Next, at least some of the reconstituted preparation is taken back up into the same syringe via the needle. The wide bore needle is then removed from the syringe and disposed of. It is replaced by a narrow bore needle for injection into the patient (intramuscularly, subcutaneously etc as appropriate).
Subsequent doses, if any, are taken up in the same way, using a new wide bore needle for uptake at each occurrence, followed by disposal of same and substitution by another narrow bore needle. It is apparent that this procedure in general is very wasteful of needles. Moreover, it tends to cause degradation of the septum, especially with multiple use, resulting in a loss of sterility.
The primary mechanism of this degradation is known as "coring" whereby the opening at the needle tip removes a section of the septum. The resulting fragment may fall into and contaminate the contents of the vial or else block the needle. The wide bore needles are used for uptake, inter alia to minimize coring, but cannot completely overcome the problem.
FIG. 1 shows a known device 1 for multiple extraction from a vial after reconstitution by the conventional method. This device provides a hollow steel needle 3 terminating in a female luer 5 at the end 7 opposite to the open needle point 9. The needle is used to pierce the septum 11 of a vial.
Syringes without needles attached are then successively attached to the luer to draw-up individual doses. The flange 13 limits the extent of insertion and the cap 15 is used to close the device between uses. However, this known system does not solve the problem of coring and septum degradation, if a wide bore needle is first employed to reconstitute the preparation in the vial.
It is also known to provide a transfer adaptor comprising a steel needle having a point at each end, thereby to transfer contents between two septum-sealed bottles, an integral collar or shroud surrounding each point.
All such transfer systems described above employ steel needles of one kind or another. However, recently there has been a growing demand to minimize use of such needles. The intention is to avoid accidental pricks or scratches from needles which may be contaminated with virally infected blood. There have been several reported incidents of hospital staff becoming infected with AIDS or hepatitis B in this way.
BRIEF DESCRIPTION OF THE INVENTION
It is an object of the invention to provide means for facilitating transfer of fluids between containers and vials, wherein the vial contains a substance to be reconstituted and the container contains a reconstituting fluid, and wherein the transfer means does not core the septum of the vial.
It is a further object to provide such a transfer means which is further capable of facilitating uptake of the reconstituted substance by a syringe, thereby reducing the number of times the septum must be pierced.
We have now discovered that a transfer adaptor for use with a vial containing ingredients to be reconstituted, an ampoule containing a reconstituting fluid and a syringe, wherein the adaptor is made preferably of plastic, is able to cut down on the wasteful use of many needles and reduce the problem of sharps.
Thus, in a first aspect, the present invention provides a transfer adaptor for fluid communication between a vial and a syringe, comprising a cannula for piercing a septum of the vial, a collar to prevent the adaptor passing into the vial through the septum, the cannula comprising a female receptor to receive the male exit nozzle of a syringe at the distal end of the cannula, characterized in that there is further provided, at the distal end of the cannula, a male receptor for the female opening of a reservoir whose contents are intended for transfer into the vial.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a known transfer device;
FIG. 2 shows a transfer adaptor and system according to the present invention;
FIG. 3 shows an alternative connector arrangement for the adaptor and system illustrated in FIG. 2;
FIG. 4 shows a further embodiment of the invention;
FIG. 5 shows a complete syringe/transfer adaptor/vial system; and
FIG. 6 shows the adaptor of FIG. 5 with an ampoule fitted thereto.
DETAILED DESCRIPTION OF THE INVENTION
Many configurations of the transfer adaptor of the present invention will be apparent to those skilled in the art, and various of the preferred embodiments are set out below.
The preferred reservoir whose contents are intended for transfer to the vial is a blow-fill seal ampoule. Such ampoules are well known in the art, and generally comprise a substantially regular shaped body having a supported, constricted neck. The neck then opens out slightly, generally in the form of a female luer, at the rim of which is sealed the cap, shown as "cap means" in FIGS. 2 and 3. This cap can be generally broken off by means of a frangible membrane around the female luer, so that the user only has to exert a sharp sideways pressure on the cap in order to reveal the contents of the ampoule via the female luer.
In the present invention, the male receptor of the transfer adaptor, in a preferred embodiment, is adapted to fit snugly into the female luer. Thus, when the assembled amopule and transfer adaptor are fitted into a vacuum-sealed vial, the vacuum will serve to encourage transfer of the ampoule contents into the vial. It will be appreciated that such transfer will be greatly facilitated by positioning the ampoule above the vial.
Configuration of the male portion of the transfer adaptor to fit within the female neck of the ampoule will generally take one of two forms. The first is to configure the male receptor of the transfer adaptor such that the contours of the male receptor exactly fit those of the female luer. This can be advantageous where a large number of transfer adaptors is manufactured in tandem with a large number of ampoules. However, if it is not known what type of ampoule is to be used in conjunction with the transfer adaptor, then it may be preferable to provide a transfer adaptor with an elongated male receptor. Thus, the base of the receptor will be broader than it is expected to encounter with a female neck of an ampoule, while the tip of the receptor will be narrower. Accordingly, such a receptor could be expected to fit most types ampoule available on the market.
In addition, it will be appreciated that transfer adaptors may be specifically tailored to fit specific types of ampoule. This may particularly be the case where ampoules contain specific substances rather than pharmaceutical grade saline. Thus, the transfer adaptor and the ampoule must be matched before transfer of the contents of the ampoule into the vial, thereby providing a double check that the contents of the ampoule are those which it is desired to transfer into the vial.
From the foregoing, it will be appreciated that the male portion of the transfer adaptor is preferably essentially luer-shaped, but that it may be any suitable shape to cooperate with any suitable ampoule, as desired. It will be appreciated that the term "luer" defines a specific frustoconical shape, whether male or female. Accordingly, "essentially luer-shaped" defines a frustoconical shape which, while not necessarily being a luer, is generally similar thereto.
The cannula of the transfer adaptor of the present invention is preferably in the form of a needle. In order to prevent coring, the opening of the cannula is preferably either set off-centre, or the edges of the rim are rounded. In practice, the walls of the cannula are likely to be so thin at the lip, that rounding the edges of the rim is unlikely to adequately prevent coring. Accordingly, it is preferred to provide the exit of the cannula bore in the side of the cannula.
It will be appreciated that as many openings as desired may be provided to permit maximum flow of fluid from the ampoule to the vial, but one is generally sufficient. Further, in practice, where the cannula is made of plastics material, then only one opening tends to be of practical use, as the bore is provided by a forming rod during injection molding. A requirement for two or more openings to the bore would then be a major inconvenience. However, the present invention envisages the provision of more than one opening to the bore, such as by drilling holes in the side of the cannula.
It will be appreciated from the foregoing, that the cannula may be made of plastics material. This is preferred where the entire transfer adaptor is injection molded in one piece. However, this is not a requirement of the present invention, and the cannula may be provided as a metal needle, for example. Such a needle could then a ultrasonically welded, or glued, into the remainder of the transfer adaptor.
While it is possible to provide the transfer adaptor of the present invention entirely in a suitable metal, such as light steel or aluminum, this will tend to be prohibitively expensive for mass manufacture. Such metal transfer adaptors would generally be intended for extended reuse, for example by autoclaving the transfer adaptor after use.
It is preferred to provide at least that part of the transfer adaptor, other than the cannula, in plastics material. It is further preferred to provide this part as an integral portion into which the cannula can be fitted. One such example of this would be a frustoconical male receptor fitted with a plastics collar which could then fit over the needle. Problems could occur here if the needle were tapered all of the way to the tip, but needles are known which have a substantially cylindrical base and which then taper towards to the tip. Nevertheless, as above, such a construct is unlikely to be commercially viable.
Accordingly, it is preferred to provide the entire transfer adaptor as an integral, injection-molded unit. In such an instance, the cannula could then take the form of a needle of plastics material, such as described above. It is generally preferred to provide such a needle as wide as possible, while still being able to puncture the septum of the vial. This is to permit maximum transfer of fluid. Where the orifice to the bore of the cannula is provided in the side of the cannula, then it is extremely unlikely that any coring will occur. However, even where such coring does occur, it will only occur the once, thereby preventing substantial degradation of the septum.
Similar considerations apply to the female receptor of the transfer adaptor and the male exit nozzle of the syringe as to the male receptor to the transfer adaptor and the female neck of the ampoule. Thus, the female neck, or receptor, of the transfer adaptor may be specifically designed so as to contour with the syringe, or may be tapered in an exaggerated manner so as to fit different types of syringe nozzle. However, by way of contrast to the transfer adaptor/ampoule connection, it is preferred that the female receptor of the transfer adaptor be contoured to fit exactly with the syringe nozzle. This is because the syringe is subject to considerably more manipulation than is the ampoule, so a secure fit, which is unlikely to be disturbed in the natural course of use of the transfer adaptor, is required.
The collar of the transfer adaptor need only be an abutment portion to prevent total penetration of the needle, or cannula, into the septum. However, it is generally preferred that the collar is sufficiently wide to avoid even the remotest likelihood of being pushed through the septum with the needle and, in a preferred embodiment, the collar is sufficiently wide to cover the entire septum.
It is also preferred that the collar, where it covers the entire septum, or at least where portions of the collar reach to the edge of the septum, that there is further provided a dependent flange which extends down the wall of the septum-retaining collar. This flange preferably extends all of the way around the circumference of the septum-retaining collar, but it may be interrupted, so as to provide several dependent members.
It is further preferred that, at the extent of the flange, or flanges, there is provided an inwardly directed finger or catch which is adapted to snap over the septum-retaining collar in use. Thus, when the transfer adaptor is fitted onto the vial, it is prevented from accidental removal by the inwardly projecting fingers.
Where such a flange is provided, it is preferred that it extends beyond the extent of the needle. If this is not the case, then the needle must be exactly positioned in the centre of the septum in order for the flange to cooperate with the septum-retaining collar. Where the flange is longer than the needle, however, the flange can be used to position the needle with the least amount of inconvenience. This also prevents the needle from being inadvertently contacted by the user's fingers, for example.
In a further preferred embodiment, an upwardly directed wall is provided about the male and female receptors of the transfer adaptor. This wall provides much the same purpose as the dependent flange, in that it prevents inadvertent contamination of the receptors, and can also be adapted to cooperate with the ampoule in use. Thus, when the ampoule is fitted on the male receptor, the upstanding wall serves to guide the ampoule into position. The ampoule is then retained in position while the contents are transferred into the vial.
Where the transfer adaptor is intended as a multi-use device, the upstanding wall may also be provided with a cover. This cover may be fitted separately from the transfer adaptor unit, or may be integral. Thus, the cover may be provided during the injection-molding procedure, and be attached by a living hinge.
There is no requirement for the cover to be particularly airtight, as atmospheric contamination is unlikely to play a large part in the use of such devices. Instead, the cover will generally be intended to prevent manual contamination.
While it is generally preferred to provide the transfer adaptors of the present invention as independent units, it is also envisaged that they may form part of the ampoule, for example. Thus, the ampoule may be fitted with a septum which could be punctured by the male receptor of the transfer adaptor when the unit is forced on to a vial. This and other suitable embodiments will be apparent to those skilled in the art.
In a further aspect of the present invention, there is provided a transfer adaptor for effecting fluid communication between a vial and another container, the adaptor comprising a connector for the container and a cannula for piercing a septum of the vial and for allowing passage of fluid between the vial and container, the cannula being provided with an opening in a side wall thereof.
The rim of the opening in the side wall of the cannula does not exert an appreciable force on the septum during insertion as does the opening directly at the tip of a conventional steel needle. Thus, coring is avoided. However, to minimize septum degradation further and to avoid accidental pricks or scratches to the user, it is preferred that the tip of the cannula is not needle sharp and most preferably is rounded. Conveniently, the opening in the side wall is provided at a position so that in use, it will be situated just below the septum. For the same reasons, the cannula is preferably made of a plastics material.
The connector of the adaptor is configured to receive the exit nozzle (male luer) of a syringe without a needle attached to the latter. Sequential filling of several syringes in this way is thereby permitted. When the reconstituted contents of the vial are exhausted, the vial together with the attached adaptor are disposed of. However, another aspect of the present invention overcomes the aforementioned problem of wastage of the wide bore needles used to introduce the sterile water into the vial.
Thus, another aspect of the present invention provides an injection reconstitution system comprising a blow-fill-seal ampoule which contains liquid and a transfer adaptor for effecting fluid communication between the ampoule and a vial.
Blow-fill-seal ampoules are well known in the art, for example as described in EP-A-0 327 397.
If the vial is of the kind sealed with a septum, then the transfer adaptor utilized according to this aspect of the invention preferably should contain means for piercing the septum and for co-operating in the fluid communication between the ampoule and the vial. This means may be a conventional steel needle, a cannula with an opening in the side wall thereof (as recited above) or of any other appropriate kind which may be envisaged by persons skilled in the art.
Whatever the means of connection of the transfer adaptor to the vial, with systems according to this aspect of the present invention, the adaptor is connected to the blow-fill-seal ampoule to permit transfer of the liquid to the vial to reconstitute the contents thereof. Preferably this is facilitated by the vial being sealed under vacuum. In this case, the adaptor should be connected to the blow-fill-seal ampoule before being connected to the vial, for example by piercing of a septum thereof. As used herein, the term "vacuum" refers to any pressure below ambient.
After liquid transfer has taken place, the container is removed to allow subsequent withdrawal of the vial contents.
In systems according to the present invention, it is preferred that the transfer adaptor and blow-fill-seal ampoule are provided with respective complementary fittings to enable them to be manually connected for the required transfer to be effected.
The following are also optional preferred features of transfer adaptors according to the present invention.
The connector of the adaptor may be configured in one respect for connection to a blow-fill-seal ampoule and in another respect for connection to a syringe for extraction of the vial contents. For example, the connector may be formed as a female luer to receive the male luer of a syringe. However, it may also have a tapered external profile to act as a male cone and thereby co-operate with a corresponding female connector on the blow-fill-seal ampoule.
The adaptor may also be provided with a shroud for the cannula or needle as appropriate. The shroud is preferably provided with clips on its lower periphery for clipping over the septum retention collar of the vial. This is especially useful when the vial is intended for multiple uses. Afterwards, the adaptor and vial can be disposed of as a single sharps free unit. Alternatively, the internal surface may be screw thread rifled to aid retention. This does not require a corresponding thread to be provided on the vial neck. Also, for multiple use the adaptor may also be provided with a cap to close it between uses. This cap may be attached via a strap.
In general, it is preferred that all, or as many parts as possible of the adaptor, are integral. Conveniently such an integral structure is manufactured by injection molding of homopolymer- or copolymer-polypropylene of an irradiatable type approved for medical use.
Whether or not forming part of a system according to the present invention, the adaptor is preferably presented sterile and overwrapped.
A yet further aspect of the present invention provides a method of preparing an injectable composition, the method comprising transferring a reconstitution liquid from a blow-fill-seal ampoule to a vial containing an unreconstituted composition by means of a transfer adaptor and subsequently drawing reconstituted injectable composition into a syringe from the vial via the transfer adaptor.
Referring now to the drawings, FIG. 2 shows a transfer adaptor 21 which comprises a rigid cannula 23 having a central bore 25. The upper end (proximal) 27 of the cannula is integral with a female luer 29 which is intended as a connector and defines a receiving chamber 31 which communicates with the bore. The tip 33 of the cannula is rounded. The lower end 35 of the bore terminates in an opening 37 in the side wall 39 of the cannula. The opening may be provided higher in the cannula so that, when the cannula is inserted through a septum (as described below), the opening will be just below the latter.
A cannula shroud 41 extends from approximately the mid-point along the length of the cannula. The lower periphery 43 of the shroud extends to below the lower (distal) end 33 of the cannula and is provided with inwardly extending clips 45, 47.
A strap 49 depends from the cannula at a point between the shroud and the luer. A cap 51 is attached to the end 53 of the strap opposite to the point of attachment.
The inner surface 55 of the female luer 29 is provided with circumferential ribs 57, 59 facing into the receiving chamber, although in some embodiments, the ribs may be omitted.
The lower end of the receiving chamber tapers inwardly frustoconically to terminate in an annular rim 60 at the junction with the cannula bore.
The entire adaptor is injection molded as a single piece.
In use, an ampoule 61 which contains sterile water is opened and a male luer 63 of the ampoule is introduced into the receiving chamber of the female luer of the adaptor. Sealing and temporary retention is facilitated by the ribs 57, 59. However, if these are omitted, then the tolerances of the respective parts are engineered to enable an interference fit to achieve the desired sealing and retention. Sealing is also enhanced by abutment of female portion 63A of the male luer 63 against the annular rim 60.
The adaptor with the ampoule attached is then pushed over the neck 65 of a vial 67, which contains a dried injectable composition, so that the tip of the cannula punctures the rubber septum 69 of the vial. The septum seals against the side wall of the cannula so that external air is excluded from the vial. The adaptor is pushed down until the upper flange 71 of the shroud abuts the upper rim 73 of the vial neck and the clips 45, 47 engage the lower rim 75 of the neck. As mentioned above, screw rifling on the inner surface 76 of the shroud is an alternative means of achieving retention.
As soon as the cannula has punctured the septum, a vacuum in the vial draws the water from the ampoule through the adaptor and into the vial to reconstitute the injectable composition. If necessary, this can be facilitated by shaking.
After the composition has been reconstituted, the ampoule is removed and discarded. The male luer of a syringe is then inserted into the reception chamber of the female luer. The luer of the syringe corresponds in external shape and dimensions to those of the male luer on the blow-fill-seal ampoule. The syringe is then operated to draw-up a desired amount of the reconstituted injectable composition.
If there is a significant delay between reconstituting the composition and charging of the syringe, or if the vial is intended for multiple use, then the cap 51 can be pushed tightly over the female luer to maintain the sterility of the vial contents. During use, the adaptor is retained on the vial by means of the clips 45, 47.
When the contents of the vial are exhausted, the vial with the attached adaptor are discarded as a single unit, having no exposed sharp protrusions, usually known as "sharps", which could come into contact with hospital personnel.
FIG. 18 shows an alternative arrangement which is essentially the same as that shown in FIG. 2, except that the external surface 72 of the connector 73 of the alternative adaptor 75 is frustoconically tapered. The latter removably engages and seals against the inside surface 77 of a female connector 79 of a blow-fill-seal ampoule 81. The latter connector is configured especially for use in this application. To that extent, the connector 73 acts as a male cone.
However, as with the embodiment shown in FIG. 2, the connector 73 is also provided with reception chamber 83 and so, in that respect, also comprises a female luer. Otherwise, the embodiment of FIG. 3 functions in the same way as that of FIG. 2. After the ampoule has been removed, the male luer of a syringe is inserted in the reception chamber of the luer 73.
FIG. 4 shows a further embodiment of the invention where the numbering indicates equivalence with that of the preceding Figures. Essentially, in this embodiment, cap 51 is attached via a living hinge 85 generated during the injection-molding process. Flanges 87 cooperate with flanges 89 to protect male luer 74. In enlargement A, it can be seen that two holes 37 are provided.
FIG. 5 is also similarly numbered. In this system male luer 63 of the syringe 61A syringe is docked in female luer 29, and needle 23 extends into vial 67, via female luer 29A. The assembly is further secured by the action of rim 46 over the bottom 75 of the septum-securing collar.
FIG. 6 illustrates the adaptor of FIG. 5 mated to an ampoule 81 via male luer 74 of the adaptor, and female luer 77 of the ampoule. Walls 101 serve to interact with strengthening walls 103 located on the neck of the ampoule.
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The present invention relates to a transfer adaptor for use with a vial containing ingredients to be reconstituted, an ampoule containing a reconstituting fluid and a syringe, the adaptor being made preferably of plastic, thereby cutting down on the wasteful use of many needles and reducing the problem of sharps.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of PPA Ser. No. 61/340,183, entitled “Device and means to obstruct propagation of electromagnetic radiation in implanted body electrodes” filed Mar. 15, 2010, by the present inventors. This application is a Continuation in Part of Ser. No. 12/586,562, entitled “Method and means for connecting a large number of electrodes to a measuring device” filed 24 Sep. 2009, published Apr. 1, 2010, and CIP of Ser. No. 12/586,763, entitled “Method and means for connecting and controlling a large number of contacts for electrical cell stimulation in living organisms”, filed Sep. 28, 2009, published Apr. 1, 2010, by the present inventors. All these are incorporated herein by reference.
FEDERALLY SPONSORED RESEARCH
[0002] Not applicable
SEQUENCE LISTING OR PROGRAM
[0003] Not applicable
BACKGROUND OR THE INVENTION
[0004] 1. Field of Invention
[0005] This invention relates to electrical stimulation of animal cells, particularly human brain and heart electrical stimulation, including spine and other types of neurons, other types of muscles and organs like bladder and stomach, and in particular to the possibility of partial obstruction of the current induced in same by electromagnetic radiation, e.g., induced during MRI (Magnetic Ressonance Imaging).
[0006] 2. Discussion of Prior Art
[0007] Several types of implanted devices for the purpose of delivering electrical pulses to different parts of the body have become practical, the most ubiquitous of which being the cardiac pacemaker, but also including DBS (Deep Brain Stimulation) and other neuronal stimulating devices, as for pain control, and other stimulators in the brain and peripheral nervous system as well, and also for other needs, as bowl control and the like. One of the disadvantages of wearing some of these, is their propensity to absorb electromagnetic waves, which are induced AC, which is subsequently released as heat in localized spots in the wearer's body, with potential for discomfort, pain, or worse, depending on the temperature increase, or electrical interference with normal neural signals. In heart pacemakers another type of danger exists, which is the transfer of induced voltage on the connecting wires to the heart, or worse, to the heart sinus pacemaker, which could induce unwanted and erratic heart beats with the potential of causing the heart to stop. In other words, the wirings act as an antenna that then is the origin of current pulses along the device. The danger also exists to totally or partly destroy the electronic circuit that controls the device if the electromagnetic induced AC propagates to it, with the potential of erratic electrical pulses, with unpredictable consequences, including death too. These implanted devices are generally composed of a battery and an electronic circuit, which is implanted near the skin, for easy access if a need arises for replacement, from where wires run to the desired electrical stimulation location, as heart, brain, spinal cord, etc. Unfortunately the connecting wires act as antennae for external electromagnetic radiation, which in turn cause an unwanted current to flow through the connecting wire, that ultimately may cause either battery or electronic circuit failure, if the pulse propagates towards the battery, or it may cause heating on the other extremity of the connecting wire, which may then be on or near the heart, brain, spinal cord, etc, wherever the stimulation happens to be. This problem may be especially acute in DBS, because the wires are longer, running from the chest to the top of the skull then down from the top, inside the skull to the bottom of the brain, making DBS a longer antenna for electromagnetic radiation than heart pacemakers are, which in turn causes more energy to be absorbed by the DBS than by the heart pacemakers. With heart pacemakers, on the other hand, though the wires are shorter, so the induced voltage is lower (also the induced energy), the very nature of the device, to pace the heart, with electrodes placed at the most efficient positions to influence the heart beat, any electrical induced voltage is potentially mortally dangerous because it can cause erratic heart beating.
[0008] Because of this possible danger, MRI images are often, or at least occasionally, avoided in patients that wear one of these implanted devices, particularly in DBS and heart pacemakers wearers, because of the longer wires on the former, and the rhythmic sensitivity of the latter. DBS wearers carry a longer antenna, from the battery/electronics in the chest with a wire running to the top of the head. Pacemakers, though having shorter wires, are less likely to develop higher power to cause dangerous heating but suffer from the danger of causing heart arrhythmias. This avoidance is a problem because implanted patients are exactly the older ones, which are the ones more likely to need imaging, X-Ray, MRI, sonography, etc. From these, MRI is the worse, because it subjects the patient to a radio frequency (RF), AC electromagnetic field of frequency on the order of 50 MHz, a frequency range used by many communications devices exactly because the antennae are so effective in this range. Because of this, at the very least the medical practitioners are prone to avoid requesting an MRI imaging on patients wearing electrical stimulating implants, particularly on a DBS wearer, who is known to be implanted with a longer wire, more prone to absorb electromagnetic energy created by the MRI imaging system.
[0009] This problem is widely recognized in the literature, and much time has been devoted to its solution, yet a complete and inexpensive solution has been eluding the designers of electrical stimulating devices.
[0010] Mark Kroll et al. U.S. Pat. No. 7,369,898, May 6, 2008 (REF_Kroll2008), recognizes the problem and teaches a method to prevent the controlling unit from being disturbed by the RF and then sending erratic stimulating pulses to the stimulation site that are not programmed in the device. Though this is an improvement, it still fails to even address the other problem of induced RF in the conducting wire that goes from the power pack box to the stimulation site. It is only a partial solution. Moreover, Kroll teaches a method that depends on the device itself recognizing the presence of strong magnetic field, then the presence of an RF, before it enters in a self-protective mode. This has the disadvantage of relying on an automatic response, which can fail to activate, as opposed to a human activated response, which can be checked by a trained professional. Above all, Kroll's solution, when and if it succeeds, is a protection for the battery and electronics package only, located in the patient chest, but not a solution for heating and unwanted electrical stimulation due to induced currents in the connecting wires. Indeed, the very solution proposed by Kroll indicates that though the community is aware of the problem and have been trying to solve it for a long time, the true solution has been eluding all, indicating the importance of an inventive, a creative solution for this problem.
[0011] Zeijlemaker et al. (U.S. Pat. No. 7,623,930, Nov. 24, 2009) (REF_Zeijlemaker2009) discloses a coordination between the telemetry system and the MRI system with the view of minimizing the possible damage, but it fails to stop the current flow due to induced electromagnetic waves in the wires that comprise the implant device. It also points to the eagerness of the community to solve a serious problem that has been eluding the practitioners of the art.
[0012] These examples show that this is a crowded field, with many practitioners of the art trying to solve a serious problem associated with electrical implants interaction with the RF electromagnetic waves used in MRI imaging. Yet, in spite of so much search and resources through in the problem, its solution has been eluding all.
Objects and Advantages
[0013] Accordingly, several objects and advantages of my invention are:
[0014] 1. To allow patients wearing electrically implanted devices to receive MRI imaging with a smaller risk of complications arising from the procedure,
[0015] 2. To decrease the level of worries by treating physician about possible complications from MRI imaging in implanted patients, therefore opening more options for his diagnostics and creating the possibility of better, more professional and accurate diagnostics,
[0016] 3. To increase the possibility that a patient wearing an electrical stimulation device will indeed have an MRI examination when one is needed for decisions on his/her health,
SUMMARY
[0017] We claim a method and means to substantially decrease the electric current induced in implanted devices, as, for example, by magnetic resonance imaging (MRI) radio frequency (RF) electromagnetic (EM) radiation from propagating through the wires of electrical devices implanted in patients subjected to MRI imaging or other electromagnetic radiation. Without such blocking, or filter, physicians are at least uneasy about requesting MRI imaging in patients wearing such implants, resulting in diminished information for treatment, at most unable to get an MRI imaging. In the worst case an imaging may cause localized heating and possibly catastrophic results, including death, or erratic heart beating, also with the possibility of death. Our device ameliorates this situation, substantially decreasing the probability that adverse side effects occurs.
DRAWINGS
[0018] FIG. 1 shows a schematic representation of the implementation of the main embodiment of this invention. Switches SW 1 (a, b, c, and d) allow current to flow into and out of the stimulating device ( FIG. 1 a ), or interrupt its flow ( FIG. 1 b ).
[0019] FIG. 2 shows a schematic representation of a variation of the implementation of the main embodiment of this invention. FIG. 2 a displays the case where the current flows through the stimulating device (normal use) and FIG. 2 b displays the case where the stimulating device is disconnected while the alternative path through resistors R-sub-a and R-sub-d are connected in a closed loop through switches SW 2 a and SW 2 d.
[0020] FIG. 3 shows a possible variation of the main embodiment with extra switches SW 1 a and SW 1 b inside the picafina of our invention, just before the beginning of the stimulating electrodes.
[0021] FIG. 4 shows an op-amp based low pass filter of the VCVS variety (Voltage-controlled voltage-source)
LIST OF REFERENCE NUMERALS
[0000]
BAT 1 =battery pack/control electronics
CW 1 and CW 2 =Control wire 1 and control wire 2
SW 1 a , SW 1 b , SW 1 c , SW 1 d , switches to turn on or off the stimulating devices and the battery/electronics pack.
ST 1 =electrical stimulating device
R 2 a and R 2 d =resistances to dissipate the energy induced by some external electromagnetic radiation in the circuit.
Wire 1 , wire 2 =two exemplary wires running from the battery pack/electronics circuit to the stimulation electrode. The former is located usually in the patient chest, while the latter is typically in the lower part of the brain, the wires going from the chest, under the skin, behind the ear, up to the top of the skull then down the brain.
WireC, wireCloop=controlling wire to connect/disconnect wires wire 1 , wire 2 , etc. and loops A 1 -A 2 -B 2 -B 1 -A 1 , etc.
WireControl 1 and WireControl 2 =control wires used to turn switches SW 1 and SW 2 on and off, as needed.
DETAILED DESCRIPTION
Preferred Embodiment
FIGS. 1 a and 1 b
[0030] We start with a shorter detailed description suitable for electronics engineers, followed by a more detailed description with less technical terms for medical personnel and general background readers. Such an approach is useful for the complete description of an invention that is of interest of practitioners of two very different fields: electronics and medicine. The first, technical description, is written for the electrical engineer, the latter, general description, is intended for neurosurgeons, neurologists, medical personnel and anyone without knowledge of the electronics circuits and electrical phenomena.
[0031] Detailed Description for Electronics Engineers.
[0032] In its main embodiment, the improvement of our invention over prior art electrical stimulating devices, is the introduction of isolation switches (in-line) to prevent propagation of RF electromagnetic waves into the critical parts of the implant, together with alternate path (or paths) in parallel with both the stimulation device (ST 1 ) and the battery/electronics (BAT 1 ) which serve to damp the electromagnetic energy induced in the connecting wires. It is of note that without the alternate path to form a closed circuit with most of the connecting wire, opening a switch leading to the stimulating device (ST 1 ) or to the battery/electronics box (BAT 1 ) is likely to cause electric potential increase at the gap with a consequent spark and destruction of the switch. The alternative paths to dump the unavoidable induced EM wave that necessarily is induced in the existing wires is an integral part of the invention we disclose. The latter (the bypass network) are necessary to forestall the destruction of the former (the in-line switches) due to the fast increase in voltage at the switch gap, though our invention is not dependent on any theory that explains the mechanism of destruction, which is added here only for completeness.
[0033] Electrical stimulating devices can be generally seen as three main components, but this arbitrary division is made here as only a simplifying subdivision to drive the attention to the parts that are important for the invention. The first component is a battery and other electrical energy source and the controlling electronics (BAT 1 ), which are usually together in a sealed box implanted in the patient's chest, near the skin for easier access; the second are the stimulating electrodes (ST 1 ), which are made in any necessary shape appropriate for the situation, which for the main embodiment we are considering to be a DBS (Deep Brain Stimulator); and finally, the third component are the wires connecting the former to the latter.
[0034] Referring to FIGS. 1 (a and b), the reader can see switches SW 1 c and SW 1 d which are near the battery pack BAT 1 and switches SW 1 a and SW 1 b , which are near the stimulating electrodes, which in this case are brain stimulating electrodes, as used in DBS (Deep Brain Stimulation), as an example only, the principle being valid for other electrical stimulation as well. Switches SW 1 (a, b, c, and d) are controlled by telemetry, either directly, or indirectly via commands received from the electronics command unit in BAT 1 , which receives commands by telemetry. The telemetry control is made with specially designed equipment that can be controlled either by the patient himself or by a neurologist, a nurse, or any other medically trained person. The electronics for this is not shown in the drawings, it being standard technology in use in many other applications. In particular existing DBS, heart pacemakers and the like do use telemetry devices to adjust the parameters of the stimulating electrical pulse, so the telemetry part is old art, not part of our invention. Our device uses additional commands not used by existing art, say, to open/close SW 1 , but these are obvious extensions for the people with experience in the arts of software and/or digital hardware design, so they will not be discussed here. It is worth to point out that current art of DBS use telemetry to select the parameters appropriate to each patient, as voltage level, for example. A trained person, capable of acting on the controls of the device, is able, using some telemetry control, to turn the switches on and off as needed.
[0035] In the main embodiment these switches are semiconductor switches activated by an electronics circuit which contains some logic and perhaps some digital addressing too. Consequently each of the switches needs to be connected to an electrical power. The main embodiment of our invention works with SW 1 of the type known as normally open switches: without power they go into the open state. To turn all off, the BAT 1 command unit has only to turn SW 1 c and SW 1 d off, which automatically turns off SW 1 a and SW 1 b because they lose power. Persons with knowledge in the art of electronics are aware that normally-open switches are not the only possible option, normally-closed switches being also possible, as well as mechanical switches, three-state switches, and more. A semiconductor, normally-open switch is suggested here only as a concrete case, it not being our intention to limit our invention to this option.
[0036] Referring still to FIGS. 1 a and 1 b , resistances R-sub-a and R-sub-d are to provide and alternative path to the induced current in the wires after switches SW 1 (a, b, c and d) are opened. R-sub-a and R-sub-d can be considered as a resistive load for the isolated network. The value of the resistances R-sub-a and R-sub-d are such that their impedances (resistances) is much larger than the total impedance from SW 1 a to SW 1 b through the network branch that includes the stimulating device, that is, the total impedance from a through SW 1 a , the wire connecting SW 1 a to the stimulating device ST 1 , the impedance of ST 1 , the impedance of the wire that connects this latter to SW 1 b , and finally the impedance of SW 1 b . Saying it in other words, the value of the resistance R-sub-a is much larger than the total value of the impedance in parallel with R-sub-a which contains the stimulating device ST 1 . For the main embodiment ST 1 is a Deep Brain Stimulating (DBS) device, which has a typical impedance of Z-sub-ST 1 =1 k-Ohms, in which case R-sub-a should have a resistance R-sub-a=1000 k-Ohms=1 M-Ohms. Considering that Joule's law for resistive devices,
[0000] P=V* 2 /R,
[0037] states that for a fixed potential difference the dissipated power is inversely proportional to the resistance, with these recommended values the power dissipated in R-sub-a would be 1/1000, or 0.1% of the total power dissipated in ST 1 , which is negligible. In battery lifetime, taking into consideration that the implanted battery usually lasts 3 years, and considering that 3 years is approximately 1,000 days, this means that the extra 1/1000 power dissipated in the parallel resistor R-sub-a would decrease the battery lifetime from 3 years to a lifetime of 2 years, 11 months and 30 days (instead of 31 days), a perfectly acceptable degradation.
[0038] If R-sub-d is also 1 M-Ohm, the parallel combined resistance of R-sub-a and R-sub-b is R-par=500 Ohms, the total “lost” power would be 1/500 of the total, and the total average lifetime of the battery would decrease from a typical 3 years to 2 years, 11 months and 29 days, still very acceptable. These are approximate values for the DBS case, other stimulating devices have similar parameters, and the invention is not bound to work only with these values, as will be appreciated by persons with skills in the art of electronics. Moreover, the value of R-sub-a and R-sub-d can be different than 1 M-Ohm, as needed for each case, this particular value of 1 M-Ohm being an exemplary case only, not intended to limit our invention.
[0039] The switches SW 1 a and SW 1 b should be as close as possible to the stimulating device ST 1 , which, in the DBS case of the main embodiment, indicates that SW 1 a and b should preferentially be at the top of the skull, and switches SW 1 c and SW 1 d should be as close as possible to the battery pack/electronics controlling unit BAT 1 , which, in the normal arrangement for DBS means that SW 1 c and d should be, in the main embodiment, in the chest, just at the exit of the box which contains the battery and the electronics controlling unit.
[0040] To turn switches SW 1 off, the battery pack/electronics control package in BAT 1 turns off, upon telemetry command, switches SW 1 c and SW 1 d , which in turns automatically starves SW 1 a and SW 1 b of power, which causes these latter to go into the off state too (assuming that they are of the normally-open type switches). After the MRI session is finished, to turn the stimulating device on again the telemetry control commands the control package in BAT 1 to turn power on for SW 1 c and SW 1 d , which either automatically, or after another command, turns on the two switches close to ST 1 : SW 1 a and SW 1 b , after what the electrical stimulating device is ready for operation again.
[0041] In the main embodiment, switches SW 1 (a, b, c and d) are semiconductor switches, as a bipolar or a FET transistor, which uses less space in the implanted device, which must by necessity be small, but semiconductor switches is not a restriction to our invention, because any other type of switch that can be manufactured on the appropriate size and with bio-compatible materials is within the scope of the invention. The necessary electronics, as transistors, etc., easily fit in the space: REF_DieSize. In particular, switches SW 1 c and SW 1 d , which are located near the battery pack/electronics (BAT 1 ) can easily be other technology, as mechanical switches, etc., for robustness, given that they can be inside or at the exit port of the battery BAT 1 , with more space available.
[0042] It will not escape the persons with knowledge in the art of electronics that the same principles apply to other electrical stimulation, as heart stimulation (heart pacemakers), neural stimulators (as for pain control), physiological electrical stimulators (as for bowel movement control, bladder control, etc.), and devices to cause muscle contraction, as in artificial limbs, etc. all of which causes problems with MRI imaging because all of them needs a relatively long wire, which acts as an antenna for the MRI RF radiation.
[0043] Detailed Description for General Background Readers.
[0044] Before we describe our invention to the readers that are familiar with the medical aspects of the invention but not familiar with the electronics aspects of it, we want to remind the readers that the devices used in current art, whether used for DBS, stimulation for epilepsy or other neurological malfunctions, heart pacemaking, spinal stimulation, etc. generally contain a sophisticated electronics circuit inside the same box that houses the battery pack (BAT 1 ). This electronics circuit is capable of adjusting the parameters of the electrical stimulation upon command send by telemetry (action at a distance, as radio waves). For DBS, which is the example used for the main embodiment, the controlling circuits can adjust the stimulating voltage (or current), the pulse frequency and duration, and more. Our device makes use of some extra commands to be added to this existing set in the current art. It should therefore be clear to persons without electronics experience that the possibility of turning on/off the switches SW 1 (a, b, c and d) is a simple extension of current art.
[0045] During MRI imaging the patient is put inside a strong and homogeneous magnet field, over which there is a slowly space varying magnetic field, and to an electromagnetic (EM) wave of a frequency on the order of 50 MHz, the actual value depending on the strength of the magnetic field. From now on we will refer to this as the RF field or as the 50 MHz wave, though 50 is only an approximate value. The 50 MHz frequency used for MRI is similar in value to the frequency that is used for communications, and is approximately half the frequency used for FM and traditional TV transmission. FM radio reception is affected by the passage of people in front of the radio (if the radio is using its own antenna, and not an external antenna), a fact that can easily be observed walking in front of an inexpensive FM radio receiver, as a bedside clock-radio, which works around 100 Mhz. This signal variation indicates that the FM frequency is capable of interacting with the human body—else there would be no change due to the appearance of a human near the radio; AM does not change as one walks around the radio, because our bodies do not interact with the frequency used for AM, which is around 1 MHz. MRI uses a slightly lower frequency than FM, that is also capable of interacting with the human body. By controlling this EM wave and measuring it after it interacts with the patient, that is, how much of it is absorbed, an image of the atoms inside the body, according to each atom's environment (or the cell structure), can me constructed. Since different tissues have different combinations of atoms and different environment around the same atom, the effect of each tissue on the EM wave is different and measuring this slight changes an image can be made. The EM wave in itself causes no harm to the patient, as it is of a frequency similar to the waves used in communications, a little lower in frequency than the frequency used for FM radio. Some fire, police and other similar services use frequencies near the frequencies used by MRI, at 30 MHz (VHF low), but this information is put here only for completeness, and its accuracy and completeness should not be considered against our invention, because it is independent of our invention and is only included for general understanding of radio frequency EM waves.
[0046] The patient undergoing the imaging cannot wear any ferromagnetic metal as iron, because these would be attracted by the strong magnetic field. Any other non-magnetic metal, as copper, aluminum, titanium, even if it is not attracted by the strong magnetic field, causes another adverse effect, as it functions as an antenna for the RF radio frequency wave used for the imaging. The long wire, acting as an antenna, does the same job as an ordinary radio antenna, capturing the radio waves existing in its environment. It happens that metals are far more effective in absorbing electromagnetic waves than human tissues, this being why antennas are usually made with metallic wires, and consequently most of the 50 MHz power used for the image is absorbed by the wires from the battery pack/electronics to the implanted device. Given that the imaging 50 MHz power is very large, the induced voltage and current in the wires can be enough to either destroy the battery pack/electronics or else to heat up the device enough to cause tissue damage. In other words, since the MRI imaging machine bombard the patient with strong, powerful radio frequency waves, as needed for a better imaging, it follows that stronger currents can appear in the wires. This is similar to having a radio near the transmitting antenna and far from it, an effect that one can see driving away from a city: eventually the signal fades away, because the signal strength becomes too low to be captured, the induced voltage too low, or conversely, eventually a station appears on the radio as one approaches a city, because the signal increases in intensity, the induced voltage in the antenna increases its value. It follows that DBS implanted patients may be subjected to induced voltages, and then to the induced currents caused by the induced voltage, in the long wire that runs under the skin from the battery and electronics BAT 1 , usually implanted in his/her chest, up and along the neck to the top of his/her skull then down again to the base of the brain inside the skull. Indeed, this is a several feet long wire, which acts as a good antenna for the approximately 50 MHz frequency waves used in MRI imaging. It happens that the radio frequency waves used in imaging are quite powerful, as the requirement is to interact with weakly interacting body molecules, which in turn means that the radio waves induced in the wire running under the skin may deposit uncomfortably large electrical energy, with the potential of causing heat, including in the brain. The problem of induced radio waves EM energy is not present in normal situations as the patient walks around town, because the normal energy level of the existing radio waves is quite low. It is only the concentration of radio EM energy inside the confined space of the MRI device that can be potentially dangerous. As an exemplary situation we can mention the production of light by fluorescent lamps just standing alone in the air but near a powerful radio transmitting antenna; the high EM fields existing in the close vicinity of the transmitting antenna is enough to cause the fluorescent lamp to produce light without the normal connection with the standard electrical power. A coil near a high-voltage transmission line is able to power some devices, a practice that found its way to the legislature, laws having been passed to forbid the practice because it is a way to capture the electrical energy from the air without paying for it. Analogously to the car approaching and receding a town, in principle one can do the same capture of the electrical energy at any home in town, but in town the 60 Hz wave is lower voltage, too weak to be practical to capture it from the air.
[0047] Regarding the total power radiated by the RF imaging coils, it depends on the particular MRI system that is used, but it can easily be around 50 ordinary pressing irons set for full heat—quite a lot of heat indeed!
[0048] It is not possible to prevent the induction of EM waves in the wires. Shortening the wires would improve the situation, because the energy induced is proportional to the length of it, among other factors, which could be achieved placing the battery and controlling electronics in the head, nearer to the point of stimulation. But other limitations, among them space in the head, prevent, or make it difficult, to lodge the battery and electronics in the head. In other situations, as heart pacemaker, for example, the points of insertion of the wire for the heart pacemaker, which typically is in the artery/vein near the clavicle also determine a relatively long wire for heart pacemaker too. So far a solution for the length of the wire has not been found and a long wire inevitably captures more EM waves. This has been the conundrum faced by physicians that need MRI images of patients implanted with DBS devices. Our invention seeks to ameliorate this problem of EM waves induced in the long wires that lead from the battery located in the chest to the DBS electrodes ST 1 implanted in the brain.
[0049] It is not possible to prevent the EM induction (the antenna effect, so to say) in the wires, so it is necessary to accept that electric energy will be induced into and then run through the wires when a wearer of electrical implanted devices is undergoing MRI, or otherwise is near any high power EM radiation. Our invention discloses the use of switches that can be closed or opened under the control of the electronics in the battery pack/electronics box BAT 1 , which can interrupt the current flow along the wires running from the battery pack to the brain, as in FIGS. 1 a and 1 b . Just opening the circuit would work, but a safety device is added to our invention, because the possibility that the EM wave induced on the wires could rise the electric potential (the voltage) on the switches, enough to cause them to arc (that is, for a spark to jump across the contacts and the switch going into conducting mode, even if only temporarily). To forestall this electrical energy accumulation on the switches SW 1 , our invention also discloses a closed loop that is used to dissipate the energy induced on it, as described in the sequel. FIGS. 1 a and 1 b display the two situations. The wires running from the battery BAT 1 to the stimulating electrode ST 1 carry the stimulation signal from the battery pack/controlling electronics BAT 1 to the brain, and SW 1 a , SW 1 b , SW 1 c and SW 1 d can be closed or opened by telemetry or some other action-at-a-distance, to close or open the electrical path from the connecting wire to the battery pack BAT 1 and to the stimulating electrode ST 1 . The resistors R-sub-a and R-sub-d are also part of the circuit. The resistance of R-sub-a and R-sub-d are of such a value that it is far more difficult for the stimulating current signal sent by BAT 1 to go through them then to go through the stimulating device ST 1 . In our main embodiment we disclose a value of 1000 larger electrical resistance for R-sub-a/R-sub-d than for the stimulating device ST 1 . The typical resistance of a DBS-type ST 1 , as used in current art, is around 1 k-Ohms, so R-sub-a and R-sub-d are 1000 k-Ohms=1 M-Ohms resistances. The equation that describes the power usage by resistive electrical devices is the Joule's law, which says that for a fixed electric potential (voltage) the power used is inversely proportional to the resistance, as 1000 times higher resistance, 1000 times less power. Consequently the fixed resistors R-sub-a and R-sub-d use 1/1,000=0.1% of the total power delivered by the battery, a very small amount of the total power delivered by the BAT 1 . Battery lifetime is important for implanted devices, because when the battery runs out, another small surgery needs to be performed to change it; a small surgery to change a box implanted just under the skin, but a surgery nonetheless. Assuming a lifetime of 3 years for the battery, which is typical, and considering that 3 years is approximately 1,000 days, the addition of the 2 resistors, each using 1/1000 of the power used by the stimulating device ST 1 , subtracts 2 days of operation (one for each resistor), therefore decreasing the total lifetime of the battery from 3 years to 2 years, 11 months and 29 days (on a 31 days month)—a very negligible and eminently acceptable decrease in battery lifetime.
[0050] Operation of the Invention
[0051] Operation of the invention for electrical engineers.
[0052] In the main embodiment of our invention, during normal operation, switches SW 1 (a, b, c, and d) are set to the conductive, or closed state (see FIG. 1 a ). In this state the main path from the electrical power source to the stimulating device is the normal path offered by the wires that run through d-a and b-c. Resistors R-sub-a and R-sub-d are in parallel with the circuit of interest (ST 1 ) but their values, being as it is suggested, 1,000 larger than the device impedance along implanted stimulating device ST 1 , represents only a minimal perturbation of the system that can safely be disregarded—at least as far as energy drain is concerned. The electrical power source is usually a battery, and is a battery for the main embodiment, but not necessarily so. This normal operation is any situation in which the patient is not subjected to very high power of radio frequency. When the patient knows that he/she is going to enter an environment of high power radio frequency, as happens during MRI imaging, the patient him/herself, or a nurse, an M.D., or any other trained personnel, using a telemetry instrument which works together with the implanted electronics in the patient's chest, in a similar way as a remote control of a TV or similar device, sends a command to the electronics in the battery pack/electronics box BAT 1 located in the patient chest to turn off (to the non-conductive or open state) switches SW 1 (a, b, c and d). Though the main embodiment discloses switches SW 1 (a, b, c, and d) as under control of the electronics in the box indicated as BAT 1 (several figures), this is not the only possibility, it being also possible that SW 1 answers to direct commands from the telemetry, or any other combination. In this state, the current that is induced in the connecting wires cannot reach the stimulating device ST 1 and the battery pack BAT 1 because it is blocked by the interrupted paths at SW 1 . The induced current on the connecting wires would then circulate on the only available closed path, which is through R-sub-a and R-sub-d ( FIG. 1 b ), dissipating the induced EM energy on R-sub-a and R-sub-d.
[0053] In the main embodiment switch SW 1 is controlled by a digital command that is sent by the electronics/control command unit in BAT 1 in the same wire as the power wire, and which is separated from the standard power to ST 1 by a high frequency pass filter followed by a digital decoder which checks if the digital sequence matches the command to open the switches SW 1 c and SW 1 d . If there is a match the switches are turned off, which starves SW 1 a and SW 1 b of power, which then turns these off too, because in the main embodiment SW 1 ( a, b, c and d ) are of the normally open type.
[0054] The main embodiment of our invention uses four switches (SW 1 a, b, c and d ) in line with two wires that run from the battery/electronics box BAT 1 to the stimulating electrodes ST 1 , that is, from the chest to the top of the head and from there into the brain: popularly known as plus and minus, more correctly known as positive and return or positive and ground or better, live and ground or return. In actuality there are several such wires carrying current to the stimulator device, so there exists a plurality of wires wire 1 , wire 2 , etc, each of which contains two switches SW 1 a and b , SW 1 c and d , etc. along its length, capable of opening its path. Switches SW 1 , in the main embodiment, are controlled by the controlling electronics, which is, in the main embodiment, packaged with the battery BAT 1 in the patient's chest. The extra wires that connect R-sub-2 create a loop to dissipate the energy induced in the wires that lead to the stimulating device ST 1 . The introduction of the closed loop is crucial for the invention, for without it the electric potential difference (often called voltage in US) would increase on the switches SW 1 a, b , etc. by the induced EMF effect, as described by Maxwell's equations, eventually causing arcing, possible destruction of the switches, and potential harm to the patient. From this controlling electronics, which is capable of receiving controlling signals by radio waves or some other type of telemetry, a wire with a command runs to the switches SW 1 a , SW 1 b , etc. In the main embodiment this is the same as the power wire, separated by a high=frequency filter to select the command for SW 1 a, b , etc. The command may be, for example, f=100 kHz to turn switch on (completing the connection), and 10 kHz to turn the switch off (disconnecting the connection), and the switches should latch once set in any state. It is also possible to have separate command wires for this control, but the main embodiment uses the same as the power wire to save space in an implanted device. In the normal situation for brain stimulation, that is, current running through SW 1 a, b, c and d , to the stimulating electrodes in the brain ST 1 , CW 1 is set to the on (or conducting state), while during MRI imaging CW 1 is set to the off state. In the former situation (stimulation working) almost all the electrical current, as set by the controlling electronics in the battery pack/electronics control BAT 1 in the patient chest, is directed to the stimulating electrode ST 1 in the brain, while in the latter situation (during MRI imaging) there is no possible electrical current path to the implanted electrodes, while an alternative path is available to dissipate the energy in the resistances along the loop a-b-c-d-a through dumping resistors R-sub-a and R-sub-d.
[0055] Operation of the Invention for General Background Readers.
[0056] Varying electromagnetic fields always induce currents on wires which are in their space. This is why antennas pick up radio signals, and why transformers work as they do. This is an unavoidable result. Therefore, the wires that carry the power or other electrical signals to the stimulating device are certain to “absorb” electrical energy from the approximately 50 MHz imaging radio frequency wave used for the MRI imaging. This “absorbed”, or induced electric current, is capable to cause harm to the wearer of implanted electrical devices, because the imaging radio frequency wave carry power equivalent to 20 or more pressing irons (20 kW or more), which is a lot of heat. Since this induced power cannot be prevented, our invention discloses a set of switches SW 1 ( a, b, c, and d ) to disconnect the battery+electronics in box BAT 1 , and the stimulating device ST 1 , of the wires that connect them. In the main embodiment the switches SW 1 ( a, b, c, and d ) are semiconductor switches. SW 1 ( a, b, c, and d ) etc. are controlled by signals sent over the power wires, blocked from the switches by a high-frequency passing filter, that is a frequency filter that only allows high frequencies to pass, which is able to pass to types of signals, at two different frequencies f 1 =10 kHz and f 2 =100 kHz, one to turn SW 1 on, the other to turn SW 1 off.
[0057] Once SW 1 is off, the continuous path through the stimulating device ST 1 and through the battery/electronics box BAT 1 is open (that is, not available to electrical conduction), which causes that the only closed path for current flow is the path that goes through resistors R-sub-a and R-sub-d, which then dumps the induced EM radiofrequency induced on the connecting wires.
[0058] Without the alternative path through R-sub-a and R-sub-d, the electric potential (known as voltage in US) would increase with the possibility of arcing and destruction of switches SW 1 , besides opening ST 1 and BAT 1 to destruction by the high current induced by the induced radio frequency signal. With the available path through R-sub-a and R-sub-d, these act as energy dump, dissipating the energy induced in the wires that are part of the implanted device.
[0059] Description and Operation of Alternative Embodiments
[0060] Several alternative embodiments are possible. For example, it is possible to have one single switch in each stimulating wire, say near the skull, SW 1 a , omitting the second switch SW 1 b , on the return wire, because once the path is broken no current can flow through stimulating electrodes ST 1 . Likewise for the battery pack/electronic circuit, it is possible to omit SW 1 d , keeping only SW 1 c , for the same reason. Redundancy may be preferable to offer more protection, this being why the main embodiment contains redundancy, a common practice in all branches of engineering, but redundancy is not necessary for the operation of the basic principle of this invention, which is to break the path for induced current while opening an alternative path to dissipate the energy induced by the high frequency external EM field.
[0061] Another alternative embodiment is to use filters F 1 a , F 1 b , etc and F 2 a , F 2 d , etc., passive or active filters, in lieu of the switches SW 1 a , SW 1 b , etc. and in line with R-sub-a, R-sub-b etc., or in lieu of these. The word “filter” is used in the art of electronics engineering to mean “frequency selective device”, devices that provide an easy flow for some frequencies and a difficult flow for other frequencies (see definitions).
[0062] This option would obviate the necessity of switches to open the circuit leading to the stimulating device ST 1 and the battery/electronics pack BAT 1 . This option would use low-pass filters (filters that pass low frequencies only) to close the path for the RF higher frequencies induced by the MRI equipment, to both the stimulating device ST 1 and the battery/electronics pack BAT 1 . A low-pass filter (that allows passage of only low frequencies) is a permanently blocking switch SW 1 for the higher frequency induced currents that cause the damage during MRI. Likewise, a high-frequency pass filter is a constantly unimpeded path to allow the flow of the induced RF (high frequency, around 50 MHz), to flow through the loop composed of resistors R-sub-a and R-sub-d. For example, a low-pass filter F 1 could permanently connect the wires that connect BAT 1 to ST 1 in place of the switches SW 1 ( a, b, c and d ), this filter designed to have low impedance Z 1 -low (low resistance, or conductive state) to the low frequency used by the stimulation signal (usually around 10 kHz, but the exact value is not part of this invention but it is old art, as practiced by neurologists), while having high impedance Z 1 -high (high resistance, or non-conductive state) for the high frequency characteristic of the induced radio frequency signals, e.g., used by imaging MRI, which is of the order of 50 MHz, depending on the static magnetic field, which is typically of the order of 2 to 5 Tesla. Such a filter F 1 , in the positions where SW 1 are located in the main embodiment, would allow the desired stimulating frequency (=˜10 kHz) to flow into the neuron stimulator ST 1 , while permanently blocking most of the energy at the much higher frequencies (=˜50 MHz) created by MRI imaging systems. Such an alternative embodiment may also have a different set of filters F 2 (high-pass filters, that pass the high frequencies) could be added in series with R-sub-a and R-sub-d, such that
[0063] Z 1 -low<<Z 2 -low<<R-sub-a (at low frequencies)
[0064] Z 1 -high>>Z 2 -high<<R-sub-a (at high frequencies),
[0065] Where low frequencies above means around 10 kHz, which corresponds to the 200 Hz stimulating signal of 100 microsecond pulsewidth, corresponding to a 10 kHz frequency, and high frequencies means 50 MHz, which are the stimulating frequencies and the imaging frequencies, respectively. Note here that the actual stimulating frequency used by existing art is 200 Hz (200 square pulses per second), but with 100 microsecond wide pulses, which corresponds to a frequency of 10 kHz. It can be proved mathematically that to pass a 100 microsecond pulse every 200 times per second (200 Hz), it takes a filter that is easy for 10 kHz.
[0066] In this case the low frequency signal (approximately 10 kHz) would find a much easier path (through Z 1 -low) to the stimulating electrode ST 1 than through the alternative parallel path through Z 2 -low and R-sub-a, while the opposite would happen with the RF high frequency induced signal at approximately 50 MHz by the MRI system, which would find an easier path through R-sub-a and R-sub-d, via Z 2 , than to the stimulating electrode ST 1 . In this alternative embodiment most of the desired signal would still go to the electrode ST 1 while most of the undesirable RF signal would still be dissipated in Ra, via Z 2 , etc, instead of depositing its energy in the electrode ST 1 or in the battery pack/electronics BAT 1 .
[0067] It is also possible to have other combinations of frequency filters (usually known in the electronics art simply as filters) and the main embodiment. For example, it is possible to have the main embodiment and filters F 2 described above in series with R-sub-a and R-sub-d, with high impedance for low-frequencies (around 10 kHz) and low impedance for high-frequencies (around 50 MHz). Such an addition would make the main embodiment more robust, with less wasted energy on the dumping resistors R-sub-a and R-sub-d.
[0068] It is also possible to have some of the switches SW 1 as described in the main embodiment, while others being substituted by the filters F 1 described above, for example, have SW 1 c and SW 1 d (the left side of FIG. 1 ), substituted by filters F 1 c and F 1 d.
[0069] Many other combinations are possible, as the persons with skills in the art will see, which are still in the scope of our invention.
[0070] Persons with skills in the art of medicine but not in the art of electronics can look at filters as a permanent selective switch that blocks certain signals while allowing other signals to proceed, the selection being made according to the frequencies of the signals. Persons with skills in the art of medicine but not in the art of electronics can appreciate that such a filtering is what occurs in all radio receivers, which separates a station transmitting at a certain frequency from another station transmitting at another different frequency. Frequency filters are common in the art of electronics and are a developed field.
[0071] Another possible alternative embodiment shown in FIGS. 2 a and 2 b , is to use switches SW 1 as in the main embodiment and switches SW 2 a and SW 2 d , in series with resistors R-sub-a and R-sub-d. This latter switches would be in the on, or conductive state when SW 1 is in the off, or non-conductive state, and vice-versa. During normal stimulation, which is the case all the time except during MRI imaging situations, all SW 1 are in the on state (conductive state), allowing current to flow through stimulating device ST 1 and/all SW 2 are in the off state (non-conductive state), blocking this alternative path through R-sub-a and R-sub-d. Conversely, during MRI imaging, all SW 1 would be turned, by telemetry, to the off (or non-conductive) state, and all SW 2 would be turned, by telemetry, to the on (or conductive) state, thereby isolating both the stimulating device ST 1 and the battery/electronics box BAT 1 , while connecting the alternative network a-b-c-d-a, through resistors R-sub-a and R-sub-d, where the induced RF energy is dissipated.
[0072] Another possibility is to have filters with impedances Z 1 (in the path to ST 1 ) and Z 2 (in the path of R-sub-a and R-sub-d) as above, and also switches SW 2 in series with Z 2 . Such switches SW 2 would then be of the type normally opened switches (normally not conducting), which would go into the closed state (conducting state) upon receiving a digitally-coded signal, for example, short-short-short-long-long-long-short-short-short, which would open a conductive path to filters Z 2 and R-sub-a, R-sub-d, etc. Such a variation would cause a much larger impedance (resistance) to the alternative energy-dumping path through R-sub-a, R-sub-d, etc. when the patient is in the normal state, at which times it would be preferable not to have R-sub-a, R-sub-d, etc.
[0073] Several possible alternatives are possible. One such possible variation is that the loop wires, e.g., the wire connecting points a to b, where R-sub-a and R-sub-d are located, are made of such an alloy as to offer a substantially larger resistance per unit length (resistivity), than the total resistance of the loop wire that goes from the battery to the stimulating device. For example, the total resistance of the wire connecting a to b can be 1000 times larger than the total resistance of the stimulating wire that goes from the battery to the stimulating device. Such wire with such a distributed resistance, 1000 times larger than the stimulating wire, would dissipate one thousand times less electrical energy than the stimulating wire, because the power dissipated is, according to Watt's power dissipation equation, P=delta−V/R*2.
[0074] Another possibility is to have said resistors R-sub-a and R-sub-d connected in cross: R-sub-a connected from point a to point c and R-sub-d connected from point d to point b. Such a connection, which would make an “X” in FIG. 1 , still keeping the general objective of offering an alternative path to any current induced by RF in the connecting wires.
[0075] Another possibility is to have said resistors R-sub-a and R-sub-d connected in parallel with said connecting wires from point b to point c and said return wire from point a to point d: R-sub-a connected from point a to point d and R-sub-d connected from point b do point c. Such a connection would be in parallel with connecting wires that carry the electrical current from the electrical energy source/electronics circuit to the stimulating electrodes.
[0076] Another possibility is to have several power carrying wires at different voltages (or current) levels, which opens the possibility of having different stimulating electrodes at different voltages (or current) levels. In this case each separate power carrying wire has its individual switch SW 1 .
[0077] Another possibility is to have a plurality of wires for use as control wires as normally used in digital electronics. These control wires could select one or another possible combination of functions at the stimulating device ST 1 .
[0078] Another possibility is to have a plurality of wires for use as address wires, as normally used in digital electronics. These address wires could select one of a plurality of electrodes at the stimulating device ST 1 . In this case the stimulating device has the appropriate decoder associated with each stimulating electrode (or pad), which is selected or deselected according to its own address, using the normal practices of digital addressing.
[0079] Another possibility is to have the plurality of control wires and address wires as a single wire which convey the information for the stimulating device ST 1 in a serial fashion, as, for example, USB serial connection. In this case the minimum wire number is one (plus return wire which may be common with all other wires due to the device working at low frequencies). In this case there exists a serial to parallel converter in the stimulating device ST 1 .
[0080] Another possibility is to have switches SW 1 inside the stimulating device instead of outside it as in FIG. 1 . This possibility is shown in FIG. 3 .
[0081] Another possibility is to have one or a plurality of dedicated wires (not shown) to control switches SW 1 and SW 2 (and others).
[0082] Other alternatives that are possible for the VCVS filter displayed in FIG. 4 . For example a Chebychev filter is another type of active filter, as are a Sallen-and-Key filter, a Butterworth filter, a Bessel filter, and so on. Indeed, any active filter would do a similar frequency blocking still using small size capacitors. A particular case may be better with a particular active filter, and the difference between any two filters may be larger or smaller, depending on the case, but the particular active filter type is unimportant for this invention but only that it is a frequency selective device.
[0083] Another possible alternative for the main embodiment is to have active filters placed at more places along the wires, for example, every 10 cm. along any wire, or any other spacing. Such multiple filters would contribute for the prevention of pulse propagation along the wire on a multiplicative manner, besides preventing any current build-up on the wires. Given that the filters would use power only when activated, which is expected to be rarely, there would be no power disadvantage associated with such a scheme, while offering better filtering and imaging RF blocking
Another possible alternative for the main embodiment is to have active filters and switches together all the time. In such an alternative embodiment the high frequency induced signal would always see a difficult path to the stimulator ST 1 and to the battery pack/electronics BAT 1 , on top of which the electrical path would be opened (disconnected) during MRI imaging.
[0085] Another possible alternative embodiment is for stimulating devices which uses one connecting wire only, using the body of the wearer as a return path. Some stimulating devices are of this type. In this case there exists one wire only, and only SW 1 a and SW 1 c . In this case R-sub-a and R-sub-d connect each wire extremity to the body of the wearer, which forms the return path. As it will be appreciated by electrical engineers, connecting the four switches as said does offer some degree of protection to both the battery pack BAT 1 and the stimulating device ST 1 .
[0086] One of the improvements of our invention over prior art electrical stimulating devices, is the introduction of one or several switches, in-line (along the path) of the pertinent wires, which are capable of opening the conductive electrical path on the wires going from the battery pack/electronics located on the chest to the top of the head and implanted electrode, therefore interrupting the path of the radio frequency waves induced by the MRI or other processes. Such switches, which can be located in a plurality of places along the electrical path are controlled by telemetry or some action at a distance, using radio control or the like. These controls, action-at-a-distance can act either on the controlling electronics housed in BAT 1 , which would in turn issue the appropriate commands, carried by wires or by radio signals, to the switches, or they can act directly on the switches themselves. Moreover, our invention discloses switches which are capable of being turned on or off, or to direct the electrical current one path or another, or to disconnect the wire altogether, acting upon external commands, which are send by telemetry, using the existing methods of telemetry to control and adjust the prior art devices, many of which are capable of being adjusted to the needs of each patient using an external programmer.
[0087] Accordingly, prior to an MRI imaging session, a trained technician, nurse, or medical doctor, can disconnect the normal, low impedance pathway for electrical stimulation, causing that an alternative available circuit containing a network of simple resistors (as R-sub-a, R-sub-d, etc.), or a network of simple resistors and high-pass filters, that is, filters that allow high frequency to pass with little opposition, is available for the unavoidable induced RF to dissipate the induced energy in the wires that connect the electrical stimulation device. The high-pass filters can be made with either passive or active devices.
[0088] An active filter (op-amp based) is better than a passive (RC, RLC) filter because it offers sharper transitions from passing-to-blocking frequencies. Active filters rely on an external power supply, which in most cases is no problem, but in the case of an implanted device, which runs on the power of an implanted battery, which needs surgery for replacement, the energy used by an active filter is a serious disadvantage. Indeed, given that every electrical engineer is aware of the superiority of active filters over passive ones, the inventors suggest, but this is not known for sure, and should not therefore be used against the invention, that the use of active filters were never introduced before due to their power consumption. This invention discloses a solution to this problem, as seen in the sequel. Moreover, in the majority of cases, such an active filter consumes power for no reason, because it is only needed if the patient undergoes an MRI imaging procedure, which happens only infrequently. Besides, even when a particular patient is subjected to an MRI procedure, the imaging procedure lasts for less than one hour, an insignificant time when compared with the years during which the active filter consumes the precious battery power. The solution we propose is to have one or a series of active filters, which are powered on demand by the standard telemetry (radio commands) sent to the battery/electronics pack; when not undergoing MRI imaging, or any other potentially EM exposure, the active filter is disconnected from the circuit, therefore not using the precious battery power. Immediately before an MRI imaging, the active filter is turned on and connected to the circuit as needed, providing a better blocking filter for the EM RF frequency used by the imaging procedure, offering a better protection than a passive RC or RLC filter would.
[0089] Another advantage of a active filter is their sizes. Active filters can be designed to work with small valued capacitors. Also op-amps can mimic the electrical characteristics of inductors, effectively creating an inductor-in-a-chip, which is of a size compatible with an implanted device.
[0090] Description of Alternative Embodiments for Non-Engineers.
[0091] It is not possible to prevent the EM induction (the antenna effect, so to say) in the wires, so it is necessary to accept that electric energy will enter (penetrate) the wires of the electrical stimulating devices, then travel to the stimulating device ST 1 and battery pack/electronics BAT 1 . Our invention discloses the use of selective switches that may block the electrical current, and filters that substantially blocks the propagation of such electric energy along the wires, and also of filters and alternative routes (networks) that bypass the deposited electric energy to less harmful locations in the body, as muscles. Our invention also discloses the introduction of switches SW 1 and SW 2 (a, b, c, etc.) located at strategic points in the circuit so as to eliminate or at least to minimize the damage caused by such induced currents. Induced currents can occur during MRI imaging and also in any other situation where the patient is exposed to electromagnetic radiation, the power of it increasing the danger of the consequent harm to the patient.
[0092] One possible technology to make electrical filters to selective block the flow of some currents but not others, is the use of active filters, which are built with amplifiers known as op-amps. The op-amps themselves drain electric power, which is at a premium in an implanted device whose battery requires surgery for replacement. This power drain on the battery, if continuous, would put the use of active filters or any other active circuit out of the realm of the possibility. Our invention discloses a system of switches that turns the active circuits off unless they are needed, that is, unless the patient is entering a situation that requires high frequency protection. Our invention discloses a system that drains power for its operation only when the patient needs the protection from radio frequency EM radiation from magnetic resonance imaging (MRI).
[0093] FIG. 3 shows an active filter constructed with an op-amp (operational amplifier) of the VCVS variety. Op-amps are fully functional amplifiers built in a chip, sometimes several in a chip, offering high gain, with which it is possible to built a variety of circuits, including frequency filtering circuits, or circuits that oppose the flow of AC at some frequencies only, while allowing AC current at other frequencies to pass. Active filters are more selective than passive filters, the former using external electric power to function, the latter using no external power to function. The former is based on transistors or their equivalents, the latter is based on resistors, capacitors and coils. The actual op-amp is very small; even with ancient, 80's technology, a 741 op-amp with 24 transistors, comfortably fits on a pin head, that is, on an area 500 micrometers in side. The full circuit, including the resistors and capacitors, can be made together in an area that is barely visible to the human eye with 80's technology, or to an area or 5 by 5 micrometers with Petium 4 manufacturing technology of 2004. Note that 5 by 5 micrometers is well smaller than what is visible to the naked eye. It is therefore perfectly feasible to have some such op-amp based circuits spaced along the connecting wire, such filters being so designed as to substantially block the 50 or so MHz AC induced by the MRI imaging system.
CONCLUSION, RAMIFICATIONS, AND SCOPE OF INVENTION
[0094] In the main embodiment and in its variations disclosed, the switches in line with the stimulation carrying wires are placed before, or outside the stimulating electrodes that reside in the brain. This is not necessary, it being also possible to have some interrupting switches in the stimulating electrode too.
[0095] The electronic switches can be implemented from transistors, as bipolar transistors, FETs, etc., or a specially designed commercial switch as the Fairchild Semiconductor FSA2259 (Low-Voltage 0.8 Ohm Dual-SPDTAnalog Switch, see REF_Semiconductor_Switch) or any other standard, off-the-shelf commercially available semiconductor switch, offered by many semiconductor company. Semiconductor switch is an established branch of electronics which is not part of this invention. If a commercial switch is used, it is understood that what would be used is the die, not the packaged chip, which is much too large for the application in question.
[0096] The switches can be closed or opened from a distance. The switches SW 1 , SW 2 , etc. can be controlled either by the electronics circuitry together with the battery pack or by direct telemetry, that is, from an outside command via radio, or infrared, etc. signals. The controlling commands can be digital or analog, without changing the scope of the invention.
[0097] The switches of the main embodiment and its variations can be operated by radio command, as disclosed in the main embodiment but also by other types of telemetry, as infrared, ultrasound, etc., as is obvious to the persons familiar with the art. Radio command was used only as a possible example, it not being intended to be a limitation of the invention.
[0098] The extra wires (wires WireControl 1 and WireControl 2 ) to control the switches SW 1 and SW 2 can be replaced by a digital code which can be send by the existing wires that send the pulses to the implant. This is similar to a radio controlled garage door opener, some of which send a particular digital sequence which is recognized by the garage door opener mechanism that acts accordingly. In this case the digital signal is sent by the wire, the same wire that carries the electrical stimulation pulse. It is also possible that instead of the switches be under control of the battery pack/electronics box, they are under direct control of an external device, in this case much like a garage door opener. In either case, the switches would contain a digital signal decoder to detect the digital signal with the instruction to open or to close each switch. These signals are common electronics circuits, widely used by many common devices, and are not part of this invention, which simply can be made with any of the existing prior art.
Sequence Listing
[0099] Not applicable.
DEFINITIONS
[0100] AC=Alternating current. Electric current characterized by a back-and-forth, or to-and-from motion. The standard electric power is AC, at the standard frequency of 60 Hz. Cf. DC
[0101] Active filter=In electronics, a filter, or device to select some frequencies to be accepted, while rejecting others that are rejected, which uses at least one, usually more, active devices, as transistors, op-amps and the like, which uses an external electric power source to function. Cf. passive filter.
[0102] AM=Amplitude modulation, e.g. REF_Horowitz.
[0103] DC=Direct current. Electric current that flows in one direction only along a wire.
[0104] EM=Electromagnetic.
[0105] Filter=The word “filter” is used in the art of electronics engineering to mean “frequency selective device”, devices that provide an easy flow for some frequencies and a difficult flow for other frequencies. Usage defines low-pass filters (which means low-frequency pass filters) as a filter that provides an easy path for low frequencies, and correspondingly a difficult path for high frequencies, with the equivalent modifications for high-pass filters (which means high-frequency pass filters) being a filter that provides an easy flow for higher frequencies and a difficult flow for low frequencies. In either case the frequency of transition from one case to the other is characteristic of the particular situation, and the steepness of the transition as well. There exists also band-pass filters, which provides a low, easy path for frequencies within a certain range, while providing a difficult path (that is, blocking) lower and higher frequencies outside the selected range. Electronics engineers distinguish between passive filters (made with passive devices, as R, L and C), and active filters (made with active devices, as op-amps). The latter have sharper transition curves from low-to-high impedance at the transition frequency.
[0106] FM=Frequency modulation, e.g. REF_Horowitz.
[0107] MRI=Magnetic Resonance Imaging. A modality of imaging in which the protons, mostly in hydrogen are the major responsible for the imaging signal. It is carried or produced placing the object to be imaged inside a strong magnetic field then directing RF radiation to it and measuring how much is absorbed and transmitted as a function of the magnetic field.
[0108] Passive filter=In electronics, a filter, or device to select some frequencies to be accepted, while rejecting others that are rejected, which uses exclusively passive elements, as resistors, capacitors, inductors and the like. A passive filter needs no external power to function. Cf active filter.
[0109] Radiation=a widely used term with many meanings, here used as EM (electromagnetic) radiation only. Note that “radiation” is often used as a short for “ionizing radiation”, as gamma rays, which can cause cancer. The frequencies used in this case are non-ionizing, so radiation used in this context is not cancer-causing agent.
[0110] RF=Radio frequency. General term for EM (q.v.) frequencies above audio frequencies, that is, above 20 kHz, but generally much above this. Normally the term applies to frequencies starting at the low end of the AM range (650 kHz) going to at least the upper end of FM and TV frequencies, some few hundreds MHz or more. THz is generally not considered RF anymore, but microwave.
[0111] Telemetry—used in the context of implanted devices for DBS means the transmission of information using EM waves or any similar action-at-a-distance physical phenomenon, to send instructions to modify the state of operation of the device. Typically the instructions are send to the microcontroller embedded in the battery/electronics pack located in the chest, but nothing forbids other receiving units in other locations.
REFERENCES
[0000]
Medtronic MRI 2002, http://www.medtronic.com/downloadablefiles/UC198877001EN.pdf, pg. 8, 37 ff.
REF_Horowitz Horowitz and Hill “The Art of Electronics” Cambridge University Press 2 nd ed. (1989)
REF_DieSize The Prescott, which is the codename of a 2004 version of the Pentium 4, sports 125 million transistors in 122 mm2, or about 1 million transistors per mm2. The popular 741 op-amp is made of 24 transistors, which scales to an area of 5 by 5 micrometers, invisible to the naked eye!
http://techreport.com/articles.x/6213/1
Not only is the 90 nm process smaller, but Intel is also manufacturing Prescott using seven layers of copper interconnects, instead of the six used at 130 nm. All told, the changes shrink the Pentium 4's die size to 122 mm2, from 145 mm2 for Northwood—this despite the fact Prescott's transistor count is 125 million, over twice Northwood's 55 million transistors.
Number of transistors throughout IC history, particularly microprocessors http://en.wikipedia.org/wiki/Transistor_count
REF_Semiconductor Switch
1. Fairchild Semiconductors
[0000]
http://www.fairchildsemi.com/pf/FS/FSA2259.html
FSA2259
Low-Voltage 0.8 ohm Dual-SPDTAnalog Switch
General Description
[0000]
The FSA2259 is a high-performance, dual, Single Pole Double Throw (SPDT) analog switch that features low RON of 0.8 W (typical) at 3.0V VCC. The FSA2259 operates over a wide VCC range of 1.65V to 4.3V and is designed for break-before-make operation. The select input is TTL-level compatible.
The FSA2259 features very low quiescent current even when the control voltage is lower than the VCC supply. This feature suits mobile handset applications by allowing direct interface with baseband processor general-purpose I/Os with minimal battery consumption.
Features
[0121] 0.8 W Typical On Resistance (RON) for +3.0V Supply
[0122] 0.40 W Maximum RON Flatness for +3.0V Supply
[0123] −3 db Bandwidth: >50 MHz
[0124] Low ICCT Current Over an Expanded Control Input Range
[0125] Packaged in 10-Lead UMLP (1.4×1.8 mm)
[0126] Power-Off Protection on Common Ports
[0127] Broad VCC Operating Range: 1.65 to 4.3V
[0128] HBM JEDEC: JESD22-A114
I/O to GND: 8.5 kV Power to GND: 16.0 kV
2. Pericom is a source for ASS (Application Specific Switches)
http://www.pericom.com/pdf/presentations/switch_ov.pdf REF_Kroll2008 U.S. Pat. No. 7,369,898 Kroll, et al. May 6, 2008 System and method for responding to pulsed gradient magnetic fields using an implantable medical device REF_Zeijlemaker2009 Zeijlemaker et al. “Controlling telemetry during magnetic resonance imaging”, U.S. Pat. No. 7,623,930, Nov. 24, 2009 Medtronic's New MRI Compatible Pacemaker Gets CE Mark Tuesday, Jun. 23, 2009 http://medgadget.com/archives/2009/06/medtronic.html Positive Results for Medtronic's MRI-Safe Pacemaker Thursday, May 14, 2009 http://medgadget.com/archives/2009/05/positive_results_for_medtronics_mrisafe_pacemaker.html http://www.medtronic.com/physician/mri_safety/interference.html http://www.medtronic.com/physcian/mri_safety/index.html# http://www.medtronic.com/physician/mri_safety/clinicalControversy.html http://www.medtronic.com/physician/mri_safety/safeDesign.html http://coolmristuff/wordpress.com/2009/01/05/medtronic-mri-pacing-system-shows-promise-2/Medtronic MRI Pacing System Shows Promise http://wwwp.medtronic.com/Newsroom/NewsReleaseDetails.do?itemID=1245340154210&lang=en_US advisa clinical trial: http://clinicaltrials.gov/ct2/show/study/NCT00839384 European news clip http://wwwp.medtronic.com/Newsroom/NewsReleaseDetails.do?itemId=1245340154210&lang=en_US 1. Gimbel J and Kanal E. Can patients with implantable pacemakers safely undergo magnetic resonance imaging? J Am Coll Cardiol. 2004; 43:1325-1327.
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A device to improve the safety of neuronal, heart, muscle and organ electrical stimulation devices during MRI scanning. The device consists of means to open and/or closing the circuit to the electrical stimulation device and to the battery pack, while, concomitantly, closing and/or opening another circuit to a dedicated path that dissipates the stored energy induced by the radiofrequency used in imaging MRI.
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TECHNICAL FIELD
The field of the invention is subsea drilling, including methods and apparatus for securing an umbilical to a subsea riser.
BACKGROUND
In subsea drilling operations, a marine riser with an attached umbilical is often deployed from a drill ship or platform to the sea floor. The umbilical can be configured to support subsea components, for example, the umbilical could be configured to provide subsea components with electrical, hydraulic, and optical power and control signals as well as chemical and gas delivery. A subsea umbilical is typically connected to a subsea riser concurrent with the subsea deployment of the riser. The connected assemblies of the riser and umbilical are then lowered together into the subsea environment as an integrated unit. Deploying the umbilical together with the riser allows the riser to provide support to the umbilical. However, this method can cause the deployment of the riser to be slower than otherwise possible. In addition, the known deployment methods can make servicing the riser or umbilical more difficult than otherwise because the umbilical is attached to and supported by the riser. There is a need for improved apparatus and methods for deploying and securing umbilicals.
SUMMARY
The present disclosure provides an apparatus and method for connecting an umbilical to a marine riser. The apparatus and method may be used when an umbilical is deployed independently of the deployment of the riser. The term ‘independently’ is used herein to mean that the umbilical is not necessarily coupled to the drilling riser during the time when the umbilical is lowered to the sea floor. For example, the method and apparatus can be employed in those instances when a riser is already in place in the water, extending from a drilling vessel to subsea equipment on the ocean floor. Such a deployment method is disclosed in provisional application Ser. No. 61/422,557, filed on Dec. 13, 2010, which is hereby incorporated by reference in its entirety.
The method of the present disclosure may include securing the umbilical to the riser with the assistance of a remotely operated subsea vehicle (“ROV”). The method also may include releasing the umbilical from the riser and retrieving it without removing the riser from the subsea environment.
The apparatus of the present disclosure may be in the form of an umbilical guide assembly which itself can be deployed and manipulated using a remotely operated subsea vehicle. In one embodiment of the invention, a number of umbilical guide assemblies may be employed in a spaced apart arrangement upon the riser assembly to secure an umbilical laterally and approximately parallel to a riser. This may be accomplished in a manner that allows for movement of the umbilical longitudinally with respect to the riser, which may be desirable.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a schematic illustration of a guide assembly in operation connected between a riser and an umbilical;
FIG. 2 is a top perspective view of the guide assembly according to the present disclosure with its umbilical interface in a closed position and its riser interface in a lock position;
FIG. 3 is a top perspective view of the guide assembly of FIG. 2 with its umbilical interface in an open position and its riser interface in an unlocked position;
FIG. 4 is a bottom perspective view of the guide assembly of FIG. 2 ;
FIG. 5 is a side view of the guide assembly of FIG. 2 ;
FIG. 6 is a top view of the guide assembly of FIG. 2 with its umbilical interface in a closed position;
FIG. 7 is a top view of the guide assembly of FIG. 2 with its umbilical interface in an open position;
FIG. 8 is a cross-section of a portion of the umbilical interface of FIG. 2 ;
FIG. 9 is a perspective view of an alternative embodiment of the guide assembly of FIG. 2 .
FIG. 10 is an illustration of the guide assembly of FIG. 2 being transported to the riser by a remotely operated vehicle;
FIG. 11 is an illustration of the guide assembly of FIG. 2 being connected to the riser by the remotely operated vehicle;
FIG. 12 is an umbilical being connected to the guide assembly of FIG. 2 by the remotely operated vehicle; and
FIG. 13 is a cross-section of a portion of an alternative embodiment of the umbilical interface of FIG. 2 .
DETAILED DESCRIPTION
Referring to FIG. 1 , the umbilical guide assemblies 10 are shown in operation. In the depicted embodiment the guide assemblies 10 are shown spaced apart vertically along a riser 12 and connected between the riser 12 and the umbilical 14 . The guide assemblies 10 are configured to enable installation of the umbilical after the riser 12 has been fully deployed from the drilling vessel 16 and secured to the sea floor 18 . The guide assemblies 10 are also configured to make it possible to retract the umbilical from the sea without disrupting the riser.
Referring to FIGS. 2-8 , an embodiment of the guide assembly 10 is shown in greater detail. The guide assembly 10 includes an umbilical interface assembly 20 configured to interface with an umbilical, a riser interface assembly 22 configured to interface with the riser, and a frame assembly 24 that extends between the umbilical interface assembly 20 and the riser interface assembly 22 . It should be appreciated that many other alternative embodiments of the present disclosure exist.
In the depicted embodiment umbilical interface assembly 20 includes a clam shell portion 26 and an umbilical interface actuation assembly 28 . The clam shell portion 26 is configured to be driven to an opened orientation by the umbilical interface actuation assembly 28 wherein it is arranged to receive a segment of umbilical 14 and configured to be driven to a closed orientation by the umbilical interface actuation assembly 28 wherein it retains the segment of umbilical 14 therein. The clam shell portion 26 is shown in a closed orientation in FIGS. 2, 4, and 6 and shown in an open orientation in FIGS. 3 and 7 .
In the depicted embodiment the clam shell portion 26 is configured to limit the movement of the umbilical in the horizontal plane (x-y plane) while allowing the umbilical to move freely in a vertical direction (z-direction). In the depicted embodiment, the clam shell portion 26 includes a generally cylindrical body having a first portion 30 that pivots relative to the second portion 32 . In the depicted embodiment the first portion 30 moves about axis AA while the second portion 32 is stationary when the umbilical interface actuation assembly 28 is actuated. See FIGS. 6 and 7 . In the depicted embodiment the first portion 30 pivots through at least 60 degrees (e.g., 90, degrees, 110 degrees) such that the first portion 30 is moved sufficiently out of the way so that the umbilical can be easily directed into the target area, which is adjacent the inner surface of the second portion 32 . See FIG. 7 .
In the depicted embodiment the umbilical interface actuation assembly 28 includes a frame mount 34 that supports a normally locked pivot connection 36 between the frame mount 34 and the second portion 32 of the clam shell portion 26 , and a driven pivot connection 38 between the frame mount 34 and the first portion 30 . The driven pivot connection 38 includes a hydraulic actuated device 40 that rotates the first portion 30 of the clam shell portion 26 relative to the second portion 32 of the clam shell portion 26 . When the driven pivot connection 38 is rotated it engages locking pins that retain the first portion 30 to the second portion 32 so that continuous hydraulic pressure is not needed to keep the clam shell portion 26 closed. The normally locked pivot connection 36 is configured to normally be locked to prevent movement of the second portion 32 , and configured to be mechanically unlocked to allow for movement of the second portion 32 . Direct manual movement of the second portion 32 may be desirable in the event of a malfunction of the driven pivot connection 38 or actuation assembly 28 .
In the depicted embodiment the umbilical interface actuation assembly 28 is driven by hydraulic fluid. In the depicted embodiment a hydraulic connection 42 is provided on a side surface of the frame assembly 24 . The hydraulic connection 42 is configured such that a remotely operated vehicle can remove a plug from the hydraulic connection and temporarily store (park) the plug on a holding structure 44 on the frame assembly 24 . Once the plug is removed, a hydraulic line can be provided by the remotely operated vehicle and can be directly connected to the hydraulic connection 42 .
Referring to FIG. 8 the clam shell portion 26 of the umbilical interface 20 is described in greater detail. In the depicted embodiment the geometry of the clam shell portion 26 is configured to prevent damage to the umbilical due to bending, compression or excessive wear. In the depicted embodiment the inner surface forms a sleeve having a generally cylindrical outer shape and a pair of tapered wear inserts 46 , 48 that are define its inner shape. In the depicted embodiment the wear inserts are tapered from both ends towards a central region. The minimum distance Dmin between the wear inserts 46 , 48 is slightly larger than the maximum exterior diameter of the umbilical (e.g., the maximum exterior diameter of the umbilical could be 3.5 inches and the Dmin could be 3.8 inches).
In the depicted embodiment the cross-sectional profile of the wear inserts 46 , 48 define a smooth curve wherein at least a portion of the curve has a radius of curvature that is greater than or equal to the minimum recommended radius of curvature for the umbilical. In the depicted embodiment the central portion Cp of the wear inserts has a radius of curvature Rc between 50-60 inches. This configuration prevents contact between the guide assembly and the umbilical from causing the umbilical to bend beyond its minimum recommended radius of curvature (e.g., a minimum recommended radius of curvature of 40 inches). In the depicted embodiment the entire cross-sectional profile includes a constant radius of curvature. Many alternative embodiments are also possible including embodiment with cross-sectional profiles defined by multiple curves. For example, FIG. 13 depicts one alternative embodiment wherein the cross-sectional profile includes two adjacent curves that each have a radius of curvature Rcc that is greater than or equal to the minimum recommended bend radius of the umbilical. In the depicted embodiment both curves have the same radius of curvature and the radius of curvatures are approximately 42 inches.
It should be appreciated that many other alternative configurations for the umbilical interface exists.
Referring to FIG. 9 , an alternative embodiment of the umbilical guide assembly of FIG. 2 is shown. The umbilical guide assembly 50 is similar to the umbilical guide assembly 10 . The riser interface assembly 52 of the umbilical guide assembly 50 is configured to mount to a shaft portion of the riser 12 rather than the flange located between riser sections. Like the umbilical guide assembly 10 , the umbilical guide assembly 50 is also configured such that it can be installed using a remotely operated vehicle prior to the riser being deployed and secured to the sea floor. This configuration allows for added flexibility with respect to where the guide assembly 50 can be located vertically along the riser. However, it should be appreciated that the umbilical guide assemblies are configured such that they could also be mounted to the riser prior to or during deployment of the riser either manually or via ROV.
Referring to FIGS. 10-12 , a method of securing an umbilical to a riser using the umbilical guide assembly is described in further detail. In the depicted embodiment the umbilical guide assembly 10 is shown being connected to the riser 12 with a remotely operated vehicle 60 while the riser 12 is underwater. In particular, FIG. 10 depicts a remotely operated vehicle 60 transporting the guide assembly 10 to the riser and aligning it with a portion of a riser flange located between adjacent sections of the riser 12 . It should be appreciated that in other embodiments, including the embodiment shown in FIG. 9 , the guide assembly can be connected to portions of the riser other than the flange area (e.g., main body or auxiliary lines of the riser). In the depicted embodiment after the guide assembly 10 is connected to the riser, the remotely operated vehicle locates the umbilical and transports the umbilical to the guide assembly. In the depicted embodiment the remotely operated vehicle has a curved front shovel portion that is configured to capture the umbilical and enable the remotely operated vehicle to drive the umbilical into place.
In the depicted embodiment, the remotely operated vehicle hydraulically connects to the guide assembly and actuates umbilical interface actuation assembly 28 to open the clam shell portion 26 . The remotely operated vehicle 60 maneuvers the umbilical 14 so that a section of the umbilical 14 is adjacent the second portion 32 of the clam shell portion 26 and then closes the clam shell portion 26 , thereby retaining the umbilical 14 therein and limiting the motion of the umbilical 14 in the horizontal plane while still allowing for longitudinal movement of the umbilical relative to the umbilical guide assembly.
The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.
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An apparatus and method for connecting an umbilical to a marine riser is provided. The method and apparatus can be employed in instances when a riser is already in place in the water, extending from a drilling vessel to subsea equipment on the ocean floor.
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BACKGROUND OF THE INVENTION
This invention relates to a fuel injection system for a two cycle engine and more particularly to an improved fuel injection nozzle arrangement for such an engine.
The advantages of fuel injection over carburetion are well known. Normally fuel injectors inject either directly into the combustion chamber (direct injection) or into the induction system (manifold or port injection). Each system has its own advantages and disadvantages. A difficulty with direct injection methods is that the fuel injector is subjected to the combustion chamber temperatures and pressure as the gases burn and expand. This dictates the use of expensive fuel injectors and also can give rise to the problem of servicing the fuel injector and maintaining its injection valve components free of foreign particles formed primarily by the combustion process.
Manifold injection, on the other hand, avoids the problems of direct cylinder injection but also loses many of the advantages of direct injection. That is, when direct cylinder injection is employed, it is possible to provide a stratified charge under low and medium speed running operations and hence both fuel efficiency and exhaust emission control are improved. However, with manifold injection, the ability to obtain stratification is substantially reduced due to the distance that the fuel charge flows from the injector into the combustion chamber.
Another type of fuel injector has also been proposed and may be used either with direct or manifold type of injection systems. This type of injector injects not only fuel under pressure, but also air under pressure. The air assists in dispersion and vaporization of the fuel particles. When utilized with either direct or manifold injection, the air fuel injectors have the same disadvantages as other types of fuel injectors. In addition, it is necessary with this type of injector to regulate the fuel and air pressure and provide separate valves for controlling the flow. Thus this type of injector is also more expensive, particularly if employed in conjunction with direct cylinder injection.
There are disclosed in the copending application of Masahiko Katoh and Masanori Takahashi, entitled "Fuel Injection System For Two Cycle Engine", Ser. No. 831,786, filed Feb. 5, 2992, still pending and assigned to the assignee hereof a number of embodiments of fuel injectors wherein the advantages of direct cylinder injection are employed without the disadvantages thereof by injecting fuel into the combustion chamber through one or more small nozzle ports formed in the cylinder liner and which are opened and closed by the movement of the pistons. Compressed air and fuel is supplied upstream of the nozzle port so as to provide an air fuel injection system which achieves stratification without the disadvantages of direct cylinder injectors and/or the prior art type of fuel air injectors.
Although the construction described in aforenoted copending application Ser. No. 831,786 has a number of advantages, for the most part, the embodiments of that application require the formation of the nozzle port in the cylinder wall or cylinder liner to be accurately positioned and sized. However, this means that servicing or replacement of the nozzle port is not easy and may, in fact, be difficult without completely disassembling the engine. Also, with the types of arrangement shown in that application, the amount of mixing of the fuel and air injected upstream of the nozzle port may be limited.
It is, therefore, a principal object of this invention to provide an improved fuel injection system for a two cycle engine having the advantages of direct and manifold fuel injection without the disadvantages of either and wherein the device may be easily serviced.
It is a further object of this invention to provide an improved air fuel injector that does not require separate valving and control for the air and fuel relative to each other and which has the advantages of both manifold and direct injection without the disadvantages of either.
SUMMARY OF THE INVENTION
This invention is adapted to be embodied in a fuel injection system for an internal combustion engine having a variable volume chamber defined by a pair of relatively movable components. A nozzle port extends through one of the components and is opened and closed by the relative movement of the components. A conduit extends to the nozzle port from externally of the combustion chamber and a nozzle insert is inserted into the conduit and has an inlet opening of a cross sectional area substantially the same as the conduit and an outlet opening juxtaposed to the nozzle port and having a substantially smaller effective flow area than the nozzle port. A chamber is formed between the inlet opening and the outlet opening and means delivers a pressurized gas to the chamber during at least a portion of the time when the nozzle port is open. A fuel injector also injects fuel into the chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view taken through a single cylinder of an internal combustion engine constructed in accordance with a first embodiment of the invention.
FIG. 2 is an enlarged cross sectional view taken through the nozzle port fuel, injector and air delivery system therefor in accordance with this embodiment.
FIG. 3 is an enlarged cross sectional view, in part similar to FIG. 2, and shows another embodiment of the invention.
FIG. 4 is an enlarged cross sectional view, in part similar to FIGS. 2 and 3, and shows another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIG. 1, a multi-cylinder internal combustion engine having a fuel injection system constructed in accordance with an embodiment of the invention is identified generally by the reference numeral 11. The invention is described in conjunction with a multi-cylinder reciprocating engine. However, it should be understood by those skilled in the art that the invention may also be employed in conjunction with a rotary type of engine. The application of the invention to such other types of engines and to multiple cylinder engines having varying cylinder configurations should be well within the scope of those skilled in the art in view of the following description.
The engine 11 includes a cylinder block assembly indicated generally by the reference numeral 12 in which one or more cylinder bores 13 are formed by pressed or cast in liners 14. One end of the cylinder bores 13 is closed by a cylinder head assembly 15 that is affixed to the cylinder block 12 in a known manner. A skirt 16 of the cylinder block 12 has affixed to it a crankcase member 17 which forms a closure for the other end of the cylinder bore 13.
A piston 18 reciprocates in each cylinder bore 13 and is connected to a connecting rod 19 by means of a piston pin 21. The lower end of the connecting rod 19 is journaled on a throw 22 of a crankshaft 23 that is rotatably journaled in a crankcase chamber 24 formed by the cylinder block skirt portion 16 and crankcase member 17.
An air charge for combustion in the engine 11 is drawn through an atmospheric air inlet device which may include a filter and/or silencing arrangement (not shown) which communicates with a throttle body 25 in which a manually operated throttle valve 26 is positioned. This air is delivered to a scavenge pump, indicated generally by the reference numeral 27 which, in the illustrated embodiment, is of the Rootes type and includes a pair of intermeshing rotors 28 that are driven from the crankshaft 23 in a suitable manner. The scavenge pump 27 outputs the pressurized air to a manifold 29 which terminates in a scavenge manifold 31 that at least in part circles the cylinder block 12 at its lower end around each of the cylinder liners 14. The scavenge manifold 31 delivers air to a main scavenge port 32 and a pair of circumferentially spaced side scavenge ports 33 which are opened and closed by the reciprocation of the piston 18.
An exhaust port 34 is provided in the cylinder liner 14 in confronting relationship with the main scavenge port 32 and delivers exhaust gases to an exhaust passage 35 which, in turn, communicates with an exhaust manifold and exhaust system (not shown) for exhausting the gases to the atmosphere.
The porting arrangement comprised of the main and side scavenge ports 32 and 33 and exhaust port 34 are configured so as to provide a Schnurle type of scavenging within the variable volume chamber formed by the piston 18, cylinder bore 13 and a recess 36 formed in the underside of the cylinder head 15 which variable volume chamber is indicated generally by the reference numeral 37 and is at times be referred to as the combustion chamber. It should be noted that the cylinder head recess 36 is offset from the axis of the cylinder bore 13 toward the main scavenge port 32 so as to improve the scavenging of the engine.
Spark plugs 38 are mounted in the cylinder head 15 with their gaps being disposed in the respective recesses 36 associated with each of the cylinder bores 13. The spark plugs 38 are fired in any suitable manner.
A system is also provided for injecting fuel and air under pressure into the combustion chamber 37 at a timed interval which will be described. This injection system includes a fuel injector 39 which is mounted in the cylinder block 12 in a manner to be described and which may be of the electrically controlled type. Fuel is supplied to the fuel injector 39 from a remotely positioned fuel tank 41 by means of a pressure pump 42 that is driven in a suitable manner and which discharges the fuel through a conduit 43 in which a filter 44 is disposed for delivery to a fuel rail 45 that supplies each of the injectors 39.
A pressure regulator 46 is connected with the manifold 45 through a conduit 47 and controls the fuel pressure supplied to the injectors 39 by bypassing excess fuel back to the tank 41 through a return conduit 48.
Manifold 29 has an air boost port 49 that delivers compressed air from the scavenge pump 27 to an air injection manifold 51 that is disposed on the opposite side of the cylinder block 12. The manifold 29 supplies air through a vertically extending conduit 52 which may be formed either integrally with the cylinder block 12 or separately from it and which terminates in an outlet port 53 associated with each cylinder bore 13. The outlet port 53 communicates with an accumulator chamber 54 through a check valve 55 which permits flow from the port 53 to the accumulator chamber 54 but not in the reverse direction. This construction may be best seen by reference to FIG. 2 and the description will proceed with primary reference to that figure.
The cylinder block 12 and cylinder liner 14 are provided with a conduit opening 56 that is disposed closely adjacent the main scavenge port 32 and will be open before and closed after the scavenge port 32 by the reciprocation of the piston 18. The injector nozzle 39 has a nozzle discharge port 57 which is opened and closed in any suitable manner and is surrounded by a nozzle insert, indicated generally by the reference numeral 58 that is sealed to the cylinder block 12 by means of a pair of 0 ring seals 59 and 61. The nozzle insert 58 has a first inlet opening 62 that is of a diameter substantially the same as the conduit 56 and a tapered end 63 that is provided with a nozzle port 64 that is substantially smaller in cross sectional area than the conduit 56. Fuel is sprayed into the inlet opening 62 from the injector nozzle 57 and will be discharged into the combustion chamber, in a manner to be described, during the reciprocation of the piston 18.
The nozzle insert 58 has a second opening 65 that is disposed adjacent its opening 62 which second opening 65 is generally perpendicular to the axis of the conduit 56 and also to the interior of the insert 58 and which communicates with an air port 66 that extends from the accumulator chamber 54 through the cylinder block 12 to the conduit 56. The air port 66 communicates with the area between the 0 ring seals 59 and 61 and hence air leakage will be precluded and all of the air will be delivered to the air port 65 of the nozzle insert 58.
Pressurized air is always present in the accumulator chamber 54 when the engine is running and as the piston 18 descends and opens the conduit 56, air under pressure will be discharged from the nozzle insert outlet opening 64 at a high velocity in a direction toward the cylinder head recess 36. The scavenge port 32 will then be subsequently opened and the scavenge charge will also enter the combustion chamber 37 so as to drive the exhaust gases out of the exhaust port 34.
As the piston 18 begins its upward movement, fuel will be injected by the fuel injector 39, the timing and duration being determined by the load on the engine, and this fuel will be entrained with the air flowing from the accumulator chamber 54 and discharged through the nozzle insert outlet opening 64 in an upward direction toward the spark plug 38. Fuel injection is stopped before the conduit 56 is closed. This operation will insure a stratified charge of fuel even under idle and low speed performance so as to insure good combustion in the combustion chamber. Also, the nozzle insert 58 is protected from the combustion of the gases by the piston until such a time as the charge is at a low enough temperature that no damage can occur.
It should be readily apparent that the injectors 39 may easily be removed so that the opening 64 can be inspected, cleaned or resized if desired.
In the embodiment of FIGS. 1 and 2, the nozzle insert 58 was formed integrally with the fuel injector 39. Accordingly, it was necessary to use a special fuel injector. FIG. 3 shows another embodiment of the invention, which is generally similar to the embodiment of FIGS. 1 and 2, but wherein the nozzle insert is formed as a separate element. Since the construction of the nozzle insert is the only portion of this embodiment that differs from the previously embodiment, components which are the same or substantially the same have been identified by the same reference numerals and will be described again only insofar as is necessary to understand the construction and operation of this embodiment.
In this embodiment, a nozzle insert, indicated generally by the reference numeral 101 has a first larger diameter portion 102 that is received within a counter bore 103 formed in the cylinder block 12 at the base of the conduit 56. The portion 103 has an inlet opening that is sized to receive and support the end of the injector 39 around its nozzle opening 57. An O ring seal 104 sealingly engages the area between the injector 39 and the nozzle insert 101. The injector 39 may be supported and fixed to the engine in any suitable manner.
The nozzle insert 101 has a reduced diameter nozzle outlet opening port 105 that is juxtaposed to the conduit opening 56 in the cylinder liner 14. It should be noted that the conduit opening 56 need not be the same diameter in the cylinder block 12 as in the cylinder liner 14. That is, a somewhat smaller opening may be formed in the cylinder liner 14 than in the cylinder block. Even if this is done, however, the nozzle insert opening 105 is substantially smaller in effective flow area than that of the conduit opening in the cylinder liner 14. This is to insure that the cylinder liner opening cannot become clogged with foreign material.
A chamber 106 is formed by the nozzle insert 101 and air is delivered to this chamber from the accumulator 54 through the air port 66. However, in this embodiment, an opening 107 is formed in the nozzle insert 101 which opening 107 extends perpendicularly to the conduit 56 and to the chamber 106 of the insert 101 at one side of it so as to establish a swirl in the chamber 106 which will further aid in the fuel distribution and mixing as well as vaporization. Like the previously described embodiment, the nozzle insert 101 may be easily removed for inspection, servicing and resizing.
In the embodiments as thus far described, the fuel injector 39 has had its nozzle port 57 communicating directly with the interior of the nozzle insert. In some instances, it may be desirable to have the fuel injector nozzle 57 spray fuel upstream of the injector insert so as to provide further mixing. FIG. 4 shows such an embodiment. This embodiment is generally the same as the preceding embodiments, except insofar as will be noted. For that reason, components which are the same as those of the previously described embodiments have been identified by the same reference numerals.
In this embodiment, a nozzle insert, indicated generally by the reference numeral 151 has a nozzle insert portion 152 which is configured like the nozzle insert 101 of the previously described embodiment. Therefore, the nozzle port 105 and chamber 106 have been identified by the same reference numerals. In this embodiment, however, a closure 153 is formed at the outer end of the chamber 106 and an injector nozzle receiving bore 154 is positioned adjacent the chamber 156. An O ring seal 155 sealingly engages the fuel injector 39 where it enters the nozzle opening 154.
The injector 39 and specifically its nozzle portion 57 sprays fuel into a chamber 156 that is formed directly in the cylinder block 12 and which receives air from the communication port 66. This chamber 156 is opened to the conduit 56 between the ends of the injector insert portion 152. A fuel air receiving opening 157 is formed in this portion of the nozzle insert 152 which is substantially perpendicular to the conduit 56 and also the chamber 106 and communicates the chamber 106 with the chamber 156. The 0 ring seal 61 and a further seal 158 provide a seal between the conduit 56 and the nozzle insert portion 152 on opposite sides of the opening 157 to avoid air and fuel leakage.
It should be readily apparent from the foregoing description that the described embodiments are particularly adapted in providing an efficient and low cost fuel injection system that has all of the advantages of direct and manifold fuel injectors without the disadvantages of either. In addition, the system can be easily serviced and replaced, if desired. It should be noted that the delivery system for air supply to the accumulator chamber 54 was provided by the main scavenge pump 27. However, other air sources are possible, for example, those shown in copending application Ser. No. 831,786. Various other changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.
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Several embodiments of fuel injection systems for two cycle internal combustion engines wherein fuel is injected into a conduit for delivery into the combustion chamber through a port in the cylinder liner. A nozzle insert is positioned in the conduit and has a restricted opening that forms the discharge through which fuel and gas under pressure are supplied to the combustion chamber for facilitating servicing and replacement.
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CROSS REFERENCE TO RELATED APPLICATION
This is a continuation of U.S. patent application Ser. No. 08/007,613, filed Jan. 22, 1993, (now abandoned) which is a continuation-in-part of Ser. No. 07/863,949, filed Apr. 6, 1992 (now abandoned), which is a continuation-in-part of Ser. No. 07/591,444, filed Oct. 1, 1990 (now U.S. Pat. No. 5,102,316), which is a continuation-in-part of Ser. No. 07/387,699, filed Jul. 31, 1989 (now U.S. Pat. No. 4,992,033) which is a division of Ser. No. 07/189,485, filed May 2, 1988 (now U.S. Pat. No. 4,877,382), which is a division of Ser. No. 06/899,003, filed Aug. 22, 1986 (now U.S. Pat. No. 4,767,293).
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates generally to scroll machines and more specifically to an improved axially compliant mounting arrangement for scroll type compressors and arrangement for assembling the components thereof together which greatly facilitates the assembly thereof as well as enables testing of the compressor prior to installation of the compressor in the outer shell.
A unique axially compliant mounting arrangement is disclosed in the above referenced parent application Ser. No. 899,003, now U.S. Pat. No. 4,767,293. One embodiment of this mounting arrangement utilizes an elongated leaf spring strap having opposite ends secured to a flange portion provided on the non-orbiting scroll member. The center portion of this strap is secured to a pair of upstanding spaced posts provided on the main bearing housing. A stop flange is provided on the non-orbiting scroll which engages the lower surface of the strap to limit axial movement of the non-orbiting scroll member away from the orbiting scroll. A retainer overlies the center portion of the strap and serves as a backup to aid in limiting this axial separating movement of the non-rotating scroll. While this mounting arrangement offers excellent performance and durability characteristics, it requires a substantial number of components which render it rather costly in terms of both manufacturing and assembly time and material.
Accordingly, the present invention seeks to provide an improved mounting arrangement which offers all of the advantages provided by the above described mounting system but additionally requires fewer components and hence offers substantial cost savings in both manufacturing and assembly. In one embodiment, the non-orbiting scroll member is secured to the main bearing housing by means of a plurality of bolts extending therebetween which allow limited relative axial movement between the bearing housing and the non-orbiting scroll member. In another embodiment, a separate annular ring is fixedly secured to the bearing housing in surrounding relationship to the non-orbiting scroll member and includes abutment surfaces operative to allow limited relative axial movement of the non-orbiting scroll. A third embodiment is disclosed which is similar to the second embodiment except that the annular ring is integrally formed with a portion of a two piece main bearing housing and separate axial stop means and anti-rotation means are provided. In this embodiment, the two piece main bearing housing is designed to be secured to a lower bearing housing into which the motor stator is fitted. Thus, the entire compressor may be assembled and tested if desired prior to installation of the compressor assembly in the outer hermetic shell. Additionally, this arrangement eliminates the reliance on the outer shell for relative positioning and/or alignment of the components. In a fourth embodiment, an annular stamped ring is pressfitted or otherwise fixedly secured to the non-orbiting scroll and bolted to the bearing housing. The stamped ring offers sufficient flexibility to allow limited axial movement of the non-orbiting scroll.
Each of these embodiments offer distinct advantages with respect to overcoming the often conflicting problems of minimizing the amount of high precision machining required, the need for accurately positioning the non-orbiting scroll member relative to the orbiting scroll member, minimizing the number of components required and hence the complexity and time required for assembly as well as minimizing costs without loss of durability and/or reliability of the resulting scroll compressor.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical section view of a scroll compressor incorporating a non-orbiting scroll mounting arrangement in accordance with the present invention;
FIG. 2 is a section view of the compressor of FIG. 1, the section being taken along line 2--2 thereof;
FIG. 3 is an enlarged fragmentary section view of the mounting arrangement shown in FIG. 1;
FIGS. 4-6 are views similar to that of FIG. 3 but showing other embodiments of the present invention, all in accordance with the present invention;
FIG. 7 is a fragmentary section view of a portion of a scroll compressor showing another embodiment of a non-orbiting scroll mounting arrangement in accordance with the present invention;
FIG. 8 is a section view of the embodiment shown in FIG. 7, the section being taken along line 8--8 thereof;
FIG. 9 is a section view of a slider block assembly for use in preventing rotation of the non-orbiting scroll in the embodiment of FIGS. 7 and 8;
FIG. 10 is a perspective view of the slider block shown in FIG. 9;
FIG. 11 is a perspective view of an alternative slider block for use in the embodiment of FIG. 9;
FIG. 12 is a section view of an alternative rotation limiting assembly for use in the embodiment of FIG. 7;
FIG. 13 is a perspective view of another arrangement for mounting of a non-orbiting scroll member in accordance with the present invention, portions thereof being broken away;
FIG. 14 is an enlarged fragmentary view of a portion of the mounting arrangement shown in FIG. 13;
FIG. 15 is an enlarged fragmentary section view of a modified version of the mounting arrangement shown in FIGS. 13 and 14, all in accordance with the present invention;
FIG. 16 is a fragmentary somewhat diagrammatic horizontal sectional view illustrating a different technique for mounting the non-orbiting scroll for limited axial compliance;
FIG. 17 is a sectional view taken substantially along line 17--17 in FIG. 16;
FIG. 18 is a sectional view similar to FIG. 17 but showing a further technique for mounting the non-orbiting scroll for limited axial compliance;
FIGS. 19 and 20 are views similar to FIG. 17 illustrating two additional somewhat similar techniques for mounting the non-orbiting scroll for limited axial compliance;
FIG. 21 is similar to FIG. 16 and illustrates yet a further technique for mounting the non-orbiting scroll for limited axial compliance;
FIG. 22 is a sectional view taken substantially along line 22--22 in FIG. 21;
FIG. 23 is similar to FIG. 16 and illustrates yet another technique for mounting the non-orbiting scroll for limited axial compliance;
FIG. 24 is a sectional view taken substantially along line 24--24 in FIG. 23;
FIG. 25 is similar to FIG. 16 and illustrates yet a further technique for mounting the non-orbiting scroll for limited axial compliance;
FIG. 26 is a sectional view taken substantially along line 26--26 in FIG. 25;
FIG. 27 is a view similar to FIG. 21 illustrating diagrammatically yet another technique for mounting the non-orbiting scroll for limited axial compliance.
FIG. 28 is a view similar to that of FIG. 1 but illustrating another embodiment of the present invention;
FIG. 29 is an exploded perspective view of the scroll assembly incorporated in the embodiment of FIG. 1;
FIG. 30 is a plan view of the embodiment of FIG. 28, showing the securement for the anti-rotation strap;
FIG. 31 is a section view of the compressor of FIG. 28, the section being taken along line 31--31 thereof;
FIG. 32 is a vertical section view of the scroll compressor of FIG. 28 supported in a test stand prior to installation in the outer shell; and
FIG. 33 is a view similar to FIG. 28 but showing another alternative embodiment of the main bearing assembly in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings and in particular to FIG. 1, a compressor 10 is shown which comprises a generally cylindrical hermetic shell 12 having welded at the upper end thereof a cap 14 and at the lower end thereof a base 16 having a plurality of mounting feet (not shown) integrally formed therewith. Cap 14 is provided with a refrigerant discharge fitting which may have the usual discharge valve therein (not shown). Other major elements affixed to the shell include a transversely extending partition 22 which is welded about its periphery at the same point that cap 14 is welded to shell 12, a stationary main bearing housing or body 24 which is suitably secured to shell 12 and a lower bearing housing 26 also having a plurality of radially outwardly extending legs each of which is also suitably secured to shell 12. A motor stator 28 which is generally square in cross section but with the corners rounded off is pressfitted into shell 12. The flats between the rounded corners on the stator provide passageways between the stator and shell, which facilitate the flow of lubricant from the top of the shell to the bottom.
A drive shaft or crankshaft 30 having an eccentric crank pin 32 at the upper end thereof is rotatably journaled in a bearing 34 in main bearing housing 24 and a second bearing 36 in lower bearing housing 26. Crankshaft 30 has at the lower end a relatively large diameter concentric bore 38 which communicates with a radially outwardly inclined smaller diameter bore 40 extending upwardly therefrom to the top of the crankshaft. Disposed within bore 38 is a stirrer 42. The lower portion of the interior shell 12 is filled with lubricating oil, and bore 38 acts as a pump to pump lubricating fluid up the crankshaft 30 and into passageway 40 and ultimately to all of the various portions of the compressor which require lubrication.
Crankshaft 30 is rotatively driven by an electric motor including stator 28, windings 44 passing therethrough and a rotor 46 pressfitted on the crankshaft 30 and having upper and lower counterweights 48 and 50 respectively. A counterweight shield 52 may be provided to reduce the work loss caused by counterweight 50 spinning in the oil in the sump. Counterweight shield 52 is more fully disclosed in assignee's U.S. Pat. No. 5,064,356 entitled "Counterweight Shield For Scroll Compressor", the disclosure of which is hereby incorporated by reference.
The upper surface of main bearing housing 24 is provided with a flat thrust bearing surface 53 on which is disposed an orbiting scroll 54 having the usual spiral vane or wrap 56 on the upper surface thereof. Projecting downwardly from the lower surface of orbiting scroll 54 is a cylindrical hub having a journal bearing 58 therein and in which is rotatively disposed a drive bushing 60 having an inner bore 62 in which crank pin 32 is drivingly disposed. Crank pin 32 has a flat on one surface which drivingly engages a flat surface (not shown) formed in a portion of bore 62 to provide a radially compliant driving arrangement, such as shown in assignee's aforementioned U.S. Pat. No. 4,877,382, the disclosure of which is herein incorporated by reference. An Oldham coupling 63 is also provided positioned between and keyed to orbiting scroll 54 and bearing housing 24 to prevent rotational movement of orbiting scroll member 54. Oldham coupling 63 is preferably of the type disclosed in the above referenced U.S. Pat. No. 4,877,382, however, the coupling disclosed in assignee's copending application Ser. No. 591,443 entitled "Oldham Coupling For Scroll Compressor" filed Oct. 1, 1990, the disclosure of which is hereby incorporated by reference, may be used in place thereof.
A non-orbiting scroll member 64 is also provided having a wrap 66 positioned in meshing engagement with wrap 56 of scroll 54. Non-orbiting scroll 64 has a centrally disposed discharge passage 75 communicating with an upwardly open recess 77 which is in fluid communication with a discharge muffler chamber 79 defined by cap 14 and partition 22. An annular recess 81 is also formed in non-orbiting scroll 64 within which is disposed a seal assembly 83. Recesses 77 and 81 and seal assembly 83 cooperate to define axial pressure biasing chambers which receive pressurized fluid being compressed by wraps 56 and 66 so as to exert an axial biasing force on non-orbiting scroll member 64 to thereby urge the tips of respective wraps 56, 66 into sealing engagement with the opposed end plate surfaces. Seal assembly 83 is preferably of the type described in greater detail in assignee's copending application Ser. No. 591,454 filed Oct. 1, 1990, now U.S. Pat. No. 5,156,539 and entitled "Scroll Machine With Floating Seal", the disclosure of which is hereby incorporated by reference. Scroll member 64 is designed to be mounted to bearing housing 24 and to this end has a plurality of radially outwardly projecting flange portions 68, 70, 72, 74 circumferentially spaced around the periphery thereof as shown in FIG. 2.
As best seen with reference to FIG. 3, flange portion 68 of non-orbiting scroll member 64 has an opening 76 provided therein within which is fitted an elongated cylindrical bushing 78, the lower end 80 of which is seated on bearing housing 24. A bolt 82 having a head 84 and washer 85 extends through an axially extending bore 86 provided in bushing 78 and into a threaded opening 88 provided in bearing housing 24. As shown, bore 86 of bushing 78 is of a diameter greater than the diameter of bolt 82 so as to accommodate some relative movement therebetween to enable final precise positioning of non-orbiting scroll member 64. Once scroll member 64 and hence bushing 78 have been precisely positioned, bolt 82 may be suitably torqued thereby securely and fixedly clamping bushing 78 between bearing housing 24 and washer 85. Washer 85 serves to insure uniform circumferential loading on bushing 78 as well as to provide a bearing surface for head 84 thereby avoiding any potential shifting of bushing 78 during the final torquing of bolt 82. It should be noted that as shown in FIG. 3, the axial length of bushing 78 will be sufficient to allow non-orbiting scroll 64 to slidably move axially along bushing 78 in a direction away from the orbiting scroll thereby affording an axially compliant mounting arrangement with the washer 85 and head 84 of bolt 82 acting as a positive stop limiting such movement. Substantially identical bushings, bolts and washers are provided for each of the other flange portions 70, 72, and 74. The amount of separating movement can be relatively small (e.g. on the order of 0.005" for a scroll 3" to 4" in diameter and 1" to 2" in wrap height) and hence the compressor will still operate to compress even though the separating force resulting therefrom may exceed the axial restoring force such as may occur on startup. Because the final radial and circumferential positioning of the non-orbiting scroll is accommodated by the clearances provided between bolts 82 and the associated bushings 78, threaded openings 88 in bearing housing 24 need not be as precisely located as would otherwise be required thus reducing the manufacturing costs associated therewith.
Alternatively, as shown in FIG. 4, the bolts 82 and bushings 78 may be replaced by a shoulder bolt 90 slidably fitted within openings 76' provided in the respective flange portions 68, 70, 72 and 74 of non-orbiting scroll 64. In this embodiment, the axial length "A" of the shoulder portion 92 of bolt 90 will be selected such that a slight clearance will be provided between the lower surface 91 of head portion of bolt 90 and the opposed surface of flange portion 68 when scroll member 64 is fully axially seated against scroll member 56 to thereby permit a slight axial separating movement in like manner as described above with reference to FIG. 3. Also, as noted above, surface 91 of bolt 90 will act as a positive stop to limit this axial separating movement of scroll member 64. The relative diameters of shoulder portion 92 and bore 76' will be such as to allow sliding movement therebetween but yet effectively resist radial and/or circumferential movement of scroll member 64. While this embodiment eliminates concern over potential shifting of the bushing relative to the securing bolt which could occur in the embodiment of FIG. 3, it is somewhat more costly in that the threaded holes in bearing housing 24 must be precisely located.
FIGS. 5 and 6 illustrate further alternative arrangements for mounting non-orbiting scroll member 64 to bearing housing 24. In FIG. 5, a bushing 94 is pressfitted within each of the openings 76" provided in respective flange portions 68, 70, 72 and 74. A shoulder bolt 96 is provided extending through bushing 94 and as described above with reference to FIG. 4 includes a shoulder portion 98 having an axial length "B" selected with respect to the length of bushing 94 to afford the desired axial movement of the non-orbiting scroll 64. In this embodiment, because bushing 94 is pressfitted within opening 76" it will slidably move along shoulder portion 98 of bolt 96 along with scroll member 64 to afford the desired axially compliant mounting arrangement. This embodiment allows for somewhat less precise locating of the threaded bores 88 in bearing housing 24 as compared to the embodiment of FIG. 4 in that the bushing 94 may be bored and/or reamed to provide the final precise positioning of the non-orbiting scroll member 64. Further, because the axial movement occurs between the bushing and shoulder bolt, concern as to possible wearing of the openings 76" provided in the flange portions of the fixed scroll is eliminated. As shown, bushing 94 has an axial length such that it is seated on bearing housing 24 when scroll member 64 is fully axially seated against scroll member 54 so as to provide a maximum surface area of engagement with shoulder portion 98, however, if desired, a shorter bushing 94 could be utilized in place thereof. Again, as in the above described embodiments, the head of bolt 96 will cooperate either with the end of bushing 94 or flange 68 as desired to provide a positive stop limiting the axial separating movement of scroll 64.
In the embodiment of FIG. 6, a counterbore 100 is provided in bearing housing 24 which counterbore serves as a pilot to receive an extended shoulder portion 102 of shoulder bolt 104. Again the axial length C of shoulder portion 102 will be selected so as to allow for the desired limited axial movement of non-orbiting scroll 64 and the head of bolt 104 will provide a positive stop therefor. Because the pilot counterbore can be reamed to establish the precise relative location of the non-orbiting scroll, the tolerance for locating the threaded bore may be increased somewhat. Further, this embodiment eliminates the need to provide and assemble separately fabricated bushings. Also, similarly to that described above, the relative diameters of shoulder portions 98 and 102 with respect to the bores through which they extend will be such as to accommodate axial sliding movement yet resist radial and circumferential movement.
A further embodiment of the present invention is illustrated in FIG. 7 wherein corresponding portions are indicated by the same reference numbers used in FIG. 1 primed. In this embodiment a separate annular retainer ring 106 is provided which surrounds non-orbiting scroll 64' and is securely bolted to bearing housing 24' by a plurality of fasteners 108.
Retainer ring 106 is generally L-shaped in cross section and includes an accurately machined inner peripheral surface 110 which is adapted to abut a corresponding accurately machined annular surface 112 provided on non-orbiting scroll 64' to thereby accurately radially position same as well as to guide axial movement thereof. Additionally, retainer ring 106 has an accurately machined radially inwardly facing surface portion 114 which is adapted to abut accurately machined radially outwardly facing shoulder portion 116 formed on bearing housing 24' so as to thereby accurately locate retainer ring 106 with respect thereto. This mounting arrangement also incorporates the axially compliant feature discussed above by providing a slight clearance between surface 117 of retainer ring 106 and an opposed surface 118 provided on scroll 64' both of which surfaces are accurately machined so as to provide a positive stop limiting this axial separating movement.
In order to prevent relative rotation of the non-orbiting scroll 64' with respect to retainer ring 106 and hence bearing housing 24', a slider block assembly 122 is provided on retainer ring 106. As best seen with reference to FIGS. 9-11, slider block assembly 122 comprises a block member 124 which is received within a suitably shaped radially extending slot 126 provided in a radially outwardly extending flange portion of the non-orbiting scroll member 64'. Block member 124 is generally T-shaped in cross section having a depending leg portion 130 received within a narrower portion 132 of slot 126 and oppositely extending arms 134, 136 loosely received within an upper portion 138 of slot 126 which arms serve to support block member 124 on scroll member 64'. A bolt 128 is threadedly secured within an opening 131 provided in retainer ring 106 and has a depending shaft portion 140 extending into a central opening 142 provided in block 124.
In operation, the close tolerance fit of both shaft portion 140 within bore 142 and the opposite circumferentially spaced sidewalls of leg portion 130 with the circumferentially opposed sidewalls of the lower portion 132 of slot 126 will cooperate to effectively prevent rotational movement of the non-orbiting scroll member. Further, because block 124 is free to move axially along shaft portion 140 of bolt 128, this anti-rotation assembly will not restrict the desired axial movement of the non-orbiting scroll member discussed above. Preferably, slide block 124 will be fabricated from metal.
An alternative slide block 144 is shown in FIG. 11. Slide block 144 is similar to slide block 124 with the exception that it includes a lower pair of circumferentially outwardly extending flange portions 146, 148 which may underlie the lower surface of the non-orbiting scroll 64' to thereby aid in retaining slide block 144 within slot 126.
Alternatively, in place of the slide block assembly described above, an anti-rotation clip assembly 150 may be utilized to prevent relative rotation of the non-orbiting scroll member. As shown in FIG. 12, clip assembly 150 includes a generally U-shaped first clip member 152 having a center portion secured to the undersurface of a flange portion of the non-orbiting scroll 64" by means of a suitable threaded fastener 154 and a pair of spaced substantially parallel depending leg members 155, 157. A second clip member 156 is secured to an upstanding post 158 integrally formed at a suitable location on main bearing housing 24" by means of a suitable threaded fastener. Second clip member 156 has a pair of spaced substantially parallel upwardly extending arm members 160, 162 and a raised center portion 164 seated on post 158 which together define a pair of spaced channels 166, 168 adapted to receive legs 155, 157 of first clip member 152. Clip members 152 and 156 will be aligned along a radius of the non-orbiting scroll member such that channels 166, 168 and legs 155, 157 will operate to prevent relative rotation between bearing housing 24" and non-orbiting scroll 64". Additionally, the slip fit connection between clip members 152 and 156 will accommodate the desired relative axial movement of non-orbiting scroll member 64" as noted above.
A further embodiment of an axially compliant non-orbiting scroll mounting arrangement is shown in FIGS. 13 and 14 wherein components corresponding to those shown in FIG. 1 are indicated by the same reference numbers triple primed. In this embodiment, an annular ring 170 is provided which is preferably formed from a suitable flexible sheet metal such as spring steel and is pressfitted on non-orbiting scroll member 64"'. An axially extending flange portion 172 extends around the inner periphery of ring 170 and abuts against an axially extending flange portion of non-orbiting scroll member 64"' so as to increase the engaging surface area therebetween. Ring 170 is in turn secured to bearing housing 24"' by means of a plurality of bolts 174 and sleeves 176. Preferably openings 178 in ring 170 through which bolts 174 extend will be somewhat larger in diameter than bolts 174 so as to reduce the need for precisely locating each of the taped holes in bearing housing 24"' which receive respective bolts 174.
A plurality of arcuate cutouts 180 are provided in ring 170 each being located just radially outwardly of flange 172, centered on respective bolts 174 and extending circumferentially in opposite directions therefrom. Cutouts 180 serve to increase the flexibility of ring 170 so as to accommodate the desired limited axial movement of non-orbiting scroll member 64"' as noted above. While it is believed that the pressfit engagement of ring 170 with scroll member 64"' will be sufficient to resist any relative rotational movement therebetween, additional securement means such as a pin or the like may be utilized to prevent same if desired.
An alternative embodiment of a retaining ring 184 is shown in FIG. 15. In this embodiment internally formed flange 172 is deleted and a separate retaining ring 182 is utilized to aid in securing ring 184 to non-orbiting scroll member 64"". Retaining ring 182 is generally L-shaped in cross section and sized to provide a secure pressfit engagement with non-orbiting scroll member 64"". The radially extending flange portion of retaining ring 182 may be secured to ring 184 in any suitable manner so as to insure against relative rotation therebetween. Retaining ring 182 will preferably be secured to the bearing housing by means of bolts 174' and sleeves 176' in a like manner as described above with respect to ring 170. Also, retaining ring 184 will include cutouts 180' similar to those provided on ring 170.
In FIGS. 16 through 20, there are illustrated a number of other suspension systems which have been discovered for mounting the non-orbiting scroll member for limited axial movement, while restraining same from a radial and circumferential movement. Each of these embodiments including those described above with reference to FIGS. 1 through 15, may function to mount the non-orbiting scroll member approximately at its mid-point, so as to balance the tipping moments on the scroll member created by radial fluid pressure forces.
With reference to FIGS. 16 and 17, support is maintained by means of a spring steel ring 186 anchored at its outer periphery by means of fasteners 188 to a mounting ring 190 affixed to the inside surface of shell 12, and at its inside periphery to the upper surface of flange 192 on non-orbiting scroll member 64 by means of fasteners 194. Ring 186 is provided with a plurality of angled openings 196 disposed about the full extent thereof to reduce the stiffness thereof and permit limited axial excursions of the non-orbiting scroll member 64. Because openings 196 are slanted with respect to the radial direction, axial displacement of the inner periphery of the ring with respect to the outer periphery thereof does not require stretching of the ring, but will cause a very slight rotation. This very limited rotational movement is so trivial, however, that it is not believed it causes any significant loss of efficiency.
In the embodiment of FIG. 18, non-orbiting scroll 64 is very simply mounted by means of a plurality of L-shaped brackets 198 welded on one leg to the inner surface of shell 12 and having the other leg affixed to the upper surface of flange 192 by means of a suitable fastener 200. Bracket 198 is designed so that it may stretch slightly within its elastic limit to accommodate axial excursions of the non-orbiting scroll.
In the embodiment of FIG. 19, the non-orbiting scroll 64 is provided with a centrally disposed flange 202 having an axially extending hole 204 extending therethrough. Slidingly disposed within hole 204 is a pin 206 tightly affixed at its lower end to housing 24. As can be visualized, axial excursions of the non-orbiting scroll are possible whereas circumferential or radial excursions are prevented. The embodiment of FIG. 20 is identical to that of FIG. 19 except that pin 206 is adjustable. This is accomplished by providing an enlarged hole 208 in a suitable flange on housing 24 and providing pin 206 with a support flange 210 and a threaded lower end projecting through hole 208 and having a threaded nut 212 thereon. Once pin 206 is accurately positioned, nut 212 is tightened to permanently anchor the parts in position.
In FIGS. 21 through 27, there are illustrated a number of other suspension systems which have been discovered for mounting the non-orbiting scroll member for limited axial movement, while restraining same from a radial and circumferential movement. Each of these embodiments disclose mounting arrangements that provide reaction to the non-orbiting scroll at substantially the mid point between the end plates of the scroll members as in the first embodiment, so as to balance the tipping moments on the scroll member created by radial fluid pressure forces.
In the embodiment of FIGS. 21 and 22, the non-orbiting scroll is supported for limited axial movement by means of leaf springs or straps 426 and 428 which are affixed at their outer ends to a mounting ring 430 welded to the inside surface of shell 12 by suitable fasteners 432, and to the upper surface of radially outwardly extending flange 433 of non-orbiting scroll 435 in the center thereof by means of a suitable fastener 434. The leaf springs can either be straight, as in the case of spring 426, or arcuate, as in the case of spring 428. Slight axial excursions of scroll member 435 will cause stretching of the leaf springs within their elastic limit.
In the embodiment of FIGS. 23 and 24 radial and circumferential movement of non-orbiting scroll 435 is prevented by a plurality of spherical balls 436 (one shown) tightly fit within a cylindrical bore defined by a cylindrical surface 437 on the inner peripheral edge of a mounting ring 440 welded to the inside surface of shell 12 and by a cylindrical surface 439 formed in the radially outer peripheral edge of a flange 442 on non-orbiting scroll 435, the balls 436 lying in a plane disposed midway between the end plate surfaces of the scroll members for the reasons discussed above. The embodiment of FIGS. 25 and 26 is virtually identical to that of FIGS. 23 and 24 except instead of balls, there are utilized a plurality of circular cylindrical rollers 444 (one of which is shown) tightly fitted within a rectangular slot defined by surface 446 on ring 440 and surface 448 on flange 442. Preferably ring 440 is sufficiently resilient that it can be stretched over the balls or rollers in order to pre-stress the assembly and eliminate any backlash.
In the embodiment of FIG. 27, the inside surface of shell 12 is provided with two bosses 462 and 464 having accurately machined, radially inwardly facing flat surfaces 466 and 468, respectively, disposed at right angles with respect to one another. Flange 433 on non-orbiting scroll 435 is provided with two corresponding bosses each having radially outwardly facing flat surfaces 470 and 472 located at right angles with respect to one another and engaging surfaces 466 and 468, respectively. These bosses and surfaces are accurately machined so as to properly locate the non-orbiting scroll in the proper radial and rotational position. To maintain it in that position while permitting limited axial movement thereof there is provided a very stiff spring in the form of a Belleville washer or the like 474 acting between a boss 476 on the inner surface of shell 12 and a' boss 478 affixed to the outer periphery of flange 433. Spring 474 applies a strong biasing force against the non-orbiting scroll to maintain it in position against surfaces 466 and 468. This force should be slightly greater than the maximum radial and rotational force normally encountered tending to unseat the scroll member. Spring 474 is preferably positioned so that the biasing force it exerts has equal components in the direction of each of bosses 462 and 464 (i.e., its diametrical force line bisects the two bosses). As in the previous embodiments, the bosses and spring force are disposed substantially midway between the scroll member end plate surfaces, in order to balance tipping moments.
In all of the embodiments of FIGS. 13 through 27 it should be appreciated that axial movement of the non-orbiting scrolls in a separating direction can be limited by any suitable means, such as the mechanical stop described in the first embodiment. Movement in the opposite direction is, of course, limited by the engagement of the scroll members with one another.
Another embodiment of the present invention is shown and will be described with reference to FIGS. 28-30. With reference to FIG. 28, a scroll compressor 214 is shown which is generally similar to scroll compressor 10 illustrated in FIG. 1 and includes a hermetically sealed outer shell 216 within which compressor assembly 217 is positioned. Outer shell 216 includes a cap 218 having a discharge fitting 220 secured thereto, and a transversely extending partition 222. Compressor assembly 217 includes intermeshed orbiting and non-orbiting scroll members 224, 226 respectively disposed within shell 216 along with a crankshaft 228 operatively connected to orbiting scroll member 224, a driving motor 230 including a rotor 232 affixed to crankshaft 228 and a stator 234 for effecting orbital motion of orbiting scroll member 224. Non-orbiting scroll member 226 includes a centrally disposed discharge passage 227 through which compressed fluid is discharged into the area enclosed by cap 218 and partition 222. A suitable seal 229 such as of the type disclosed in assignee's U.S. Pat. No. 5,156,539 is positioned in surrounding relationship to discharge passage 227 and engages a flange portion 231 of partition 222. A lower bearing housing 236 is also provided which is supported within and by outer shell 216. Stator 234 is supported within lower bearing housing 236 as is a bearing 238 within which the lower end of crankshaft 228 is journaled. The upper end of crankshaft 228 is rotatably supported by a main bearing assembly 240 which is secured to and supported within shell 216 by lower bearing housing 236. The operation of scroll compressor 214 as well as the other components and optional components incorporated therein are substantially the same as described above with reference to FIG. 1.
As best seen with reference to FIGS. 28 and 29, main bearing assembly 240 includes a lower portion 242 and an upper portion 244. The lower portion 242 has a generally cylindrically shaped central portion 246 within which the upper end of shaft 228 is rotatably supported by means of a suitable bearing. An upstanding annular projection 248 is provided on lower portion 242 adjacent the outer periphery of central portion 246 and includes accurately machined radially outwardly facing and axially upwardly facing locating surfaces 250, 252 respectively. A plurality of radially circumferentially spaced supporting arms 254 extend generally radially outwardly from central portion 246 and include depending portions adapted to engage and be supported on lower bearing housing 236. The lower surface of each of the depending portions of supporting arms 254 includes a step defining accurately machined radially outwardly facing surface 256 and axially downwardly facing surface 257.
Upper portion 244 of main .bearing assembly 240 as best seen with reference to FIG. 29 is generally cup-shaped including an upper annular guide ring portion 258 integrally formed therewith, an annular axial thrust bearing surface 260 disposed below ring portion 258, and a second annular supporting bearing surface 262 positioned below and in radially outwardly surrounding relationship to axial thrust bearing surface 258. As shown in FIG. 28, axial thrust bearing surface 260 serves to axially movably support orbiting scroll member 224, and supporting bearing surface 262 provides support for Oldham coupling 264. The lower end of upper portion 244 includes an annular recess defining radially inwardly and axially downwardly facing surfaces 266, 268 respectively which are designed to mate with surfaces 250 and 252 of lower portion 242 to aid in axially and radially positioning upper and lower portions 242, 244 relative to each other. Additionally, a cavity 270 is defined between upper and lower portions 244, 242 of main bearing assembly 240 positioned in surrounding relationship to the upper end of crankshaft 228. Cavity 270 is designed to accommodate rotational movement of a counterweight 272 secured to shaft 228 at the upper end thereof. The provision of this cavity enables counterweight to be positioned in closer proximity to orbiting scroll member 224 thus enabling the overall size thereof to be reduced. Additionally, the axial height of counterweight as well as the mass thereof can be further reduced as compared to counterweight 48 shown in FIG. 1 because the radial dimension thereof can be increased beyond the diameter of the rotor due to its relative positioning.
Annular integrally formed guide ring 258 is positioned in surrounding relationship to a radially outwardly extending flange portion 273 of non-orbiting scroll member 226 and includes a radially inwardly facing surface 276 adapted to slidingly abut a radially outwardly facing surface 274 of flange portion 273 so as to radially position and guide axial movement of non-orbiting scroll member 226. In order to limit the axial movement of non-orbiting scroll member 226 in a direction away from orbiting scroll member 224, a plurality of stop members 278 are provided which are secured to the top surface of annular ring 258 by bolts 280. Each of the stop members 278 includes a radially inwardly extending portion which is adapted to overlie an upper surface of guide ring 258 which forms a part of flange portion 273 of non-orbiting scroll member 226 and cooperate therewith to limit axial upward movement of the non-orbiting scroll member. As shown in FIG. 28, bolts 280 also serve to both secure upper and lower portions 244, 242 of main bearing assembly together as well as to secure this assembly to lower bearing housing 236. It should also be noted that the axial positioning of stop member 278 will be accurately controlled relative to the corresponding opposed surface of flange 273 to allow slight limited axial movement of non-orbiting scroll member 226. Alternatively, separate bolts could be utilized to secure stop members 278 to the upper surface of ring 258 or bolts 292 could be employed for this purpose. In the event such separate bolts are utilized, it may be desirable to recess the heads of bolts 280 below the upper surface of ring 258 to minimize the overall length thereof.
In order to prevent rotational movement of non-orbiting scroll member 226, an anti-rotation strap 282 is provided which includes a center portion 284 designed to be secured to non-orbiting scroll member 226 by bolt 286. The opposite ends 288, 290 of strap 282 are each secured to the upper surface of annular ring 258 by means of bolts 292 and spacers 294. As shown, the center portion of strap 282 is secured to an axially extending radially outwardly facing sidewall portion of scroll member 226 and hence lies in a plane rotated approximately 90° from the plane in which the respective outer end portions of the strap lie. This twisted construction of anti-rotation strap 282 serves not only to facilitate securement of the mid portion thereof to the non-orbiting scroll member but also aids in minimizing the concentration of stresses along the outer edges thereof.
As shown in FIGS. 28 and 31, lower bearing housing 236 is generally cup-shaped having a continuous inner annular ring portion 296 having an inner surface 300 which is adapted to supportingly engage the outer periphery of motor stator 234. A plurality of substantially identical radially outwardly extending bosses 302 are provided spaced around ring portion 296 each of which projects axially above and below ring portion 296. The lower ends of bosses 302 extend radially inwardly and merge together to form a support for lower bearing 238 in which the lower end of crankshaft 228 is rotatably supported.
The upper end of each of bosses 302 is provided with a stepped portion defining accurately machined radially inwardly facing surface 304 and axially upwardly facing surface 306 which are designed to cooperate with surfaces 256 and 257 respectively formed on supporting arms 254 of lower portion 242 so as to accurately radially and axially position main bearing housing assembly 242 relative to lower bearing housing assembly 236. As shown in FIG. 28, a threaded bore is provided opening outwardly through each of the surfaces 306 to accommodate bolts 280 which serve to secure the assembly together as mentioned above.
Additionally, as also shown in FIGS. 28, 31 and 32 each of the bosses 302 includes an axially elongated circumferentially extending radially outwardly facing surface 308 defining a segment of a cylinder which is designed to engage the inner surface 310 of outer hermetic shell 216 in an interference fit so as to radially position and support compressor assembly 217 therein. A shoulder 312 is provided at the axially upper end of each of the surfaces 310 and is designed to abut a corresponding shoulder 314 formed in outer shell 216 so as to axially position compressor assembly 217 within shell 216. It should be noted that mating shoulders 312 and 314 must be reasonably accurately positioned so as to ensure engagement between seal member 229 and flange 231 of partition 222 which defines discharge passage 318.
As may be readily appreciated from FIG. 28, compressor assembly 217 does not rely on the outer shell for retaining any of the components in assembled relationship with other components. Rather, the entire compressor assembly may be assembled in operational condition and tested prior to its installation in shell 216. Thus as shown in FIG. 32, the fully assembled operational compressor 217 may be placed in a support structure 320, connected to a source of electrical power 321 and tested to ensure correct and satisfactory operation of same. Preferably, a suitable source of lubricating oil 322 will be provided along with means such as conduit 324 to direct such lubricating oil to the lubricant pump provided in the lower end of crankshaft 228.
It should be noted that the operation and function served by integral guide ring 258 is substantially the same as that described above with respect to the embodiment of FIG. 7. Additionally, while the embodiment of FIG. 28 has been illustrated in connection with a preferred axial compliant mounting arrangement, any of the other mounting arrangements may be utilized in place thereof if desired. Similarly, the axially compliant mounting arrangement of FIG. 28 could be utilized in connection with any of the other embodiments disclosed herein. Lastly, it should be noted that the axial positioning of both flange 273 and guide ring 258 is approximately midway between the respective wrap tip and end plate of non-orbiting scroll member 226 and thus serves to minimize the tipping moment exerted thereon in the same manner as described above.
Another embodiment of the compressor 214 of FIG. 28 is shown in FIG. 33 wherein corresponding portions thereof are indicated by the same reference numbers primed. Compressor 214' is substantially identical to compressor 214 except for the construction of main bearing assembly 240'. Lower portion 242' of main bearing assembly 240' does not include any supporting arms 254 as incorporated in portion 242 of main bearing assembly 240 but rather arms 254' are integrally formed with upper portion 244'. The outer peripheral edge of portion 242' is located adjacent upstanding annular projection 248' and a plurality of circumferentially spaced fasteners 296 are provided which operate to secure lower portion 242' to upper portion 244'. As in main bearing assembly 240, abutting surfaces 250', 266' and 252', 268' will serve to aid in radially and axially positioning lower portion 242' with respect to upper portion 244'. In all other respects bearing assembly 240' is substantially the same in construction and operation as main bearing assembly 240 described above. Likewise, as is readily apparent from FIG. 33, compressor 214' may also be tested prior to assembly into shell 216' in a like manner as was described above with reference to compressor 217.
While it will be apparent that the preferred embodiments of the invention disclosed are well calculated to provide the advantages and features above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.
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A scroll type machine is disclosed which is designed to enable it to be fully assembled prior to being installed in a hermetic shell and incorporates an improved mounting arrangement for the non-orbiting scroll member. This design enables the compressor to be tested without the need to first install it in the outer shell. This feature in combination with the mounting arrangement greatly facilitates manufacturing, assembly, testing, effectively prevents radial displacement of the non-orbiting scroll member, and offers the advantages of axial compliance. In one embodiment, the non-orbiting scroll is axially movably secured to a bearing housing by means of a plurality of bolts or bolts and sleeves. In another embodiment a rigid annular ring serves to axially movably secure the non-orbiting scroll to the bearing housing while in a third embodiment a stamped ring is secured to both the non-orbiting scroll and the bearing housing. In another embodiment a two piece main bearing housing includes an integral ring for radially positioning the non-orbiting scroll member and means for securing anti-rotation and axial stop means thereto. A method of assembling and/or testing the compressor is also disclosed.
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FIELD OF THE INVENTION
This invention relates generally to power supplies, and more specifically to switching power supplies adapted to provide uninterrupted power during transient interruption of its input voltage provided by a primary source. It also specifically relates to switching power supplies that have been adapted to limit the maximum voltage presented to the voltage converter portion of the power supply. The power supply may incorporate either or both adaptations.
BACKGROUND OF THE INVENTION
Electronic equipment often requires a power supply with built in energy storage to allow continued operation during interruption of input voltage from the primary power source or to ensure orderly shutdown of equipment when primary power is removed. In certain military applications, for example, the required holdup period is fifty milliseconds. The volume of the capacitor required for such applications may be significant depending on the power that must be provided during the holdup period.
A desirable attribute of power supplies is minimal volume. The volume of the storage capacitance may be significantly decreased if the stored voltage is increased. Since the energy stored in a capacitor is proportional to the voltage squared, increasing the stored voltage by a factor of two, for example, results in a fourfold increase in stored energy. In addition, if the voltage level is not accurately controlled and/or it changes in an adverse direction as a function of temperature, the energy storage capacitor may have to be increased in size to ensure sufficient energy is stored and capacitor voltage ratings are not exceeded. Since typical energy storage capacitors experience a decrease in capacitance as temperature is reduced, and particularly so as temperatures drop toward -40° C. or less as in many military applications, it would be desirable for the stored voltage to increase with decreasing temperature to compensate for the reduced capacitance.
High power conversion efficiency is another desirable power supply attribute. The requirement of a power supply to provide well-regulated, uninterrupted power despite the presence of severe voltage transients at its input makes high power efficiency difficult to achieve. Typical phase voltage variation for a 115 volt AC nominal generator on a military aircraft may range from 80 to 180 volts AC or more. For a typical power supply, the requirement to maintain regulation throughout the input voltage range imposes the requirement for high voltage semiconductors that are inherently more inefficient and result in lower power efficiency. In terms of power efficiency, the wide transient range also forces non-optimal transformer turns ratios within the power converter(s) so that regulation is maintained over the entire input voltage range. Another drawback of requiring the power converter(s) to regulate throughout the highest voltage portion of the transient range is the greater difficultly presented to design the converter to maintain regulation below the minimum line transient level, for example, below 80 volts AC. It would be desirable to maintain regulation below this minimum level for applications where uninterruptable performance is required. Power converters would be able to draw more energy from the storage capacitor that is part of the power converter leading to further size reduction of the holdup capacitor.
Recent years have seen the emergence of a number of manufacturers of high-density DC-DC converter modules, often referred to as "bricks." Examples of these companies include Vicor, Interpoint, Abbott, and Wilorco. Electrical performance variations include input voltage range, output voltage, output power, and number of outputs. Since these bricks are small and offer a wide selection of performance parameters, with minimal additional passive components such as resistors and capacitors they can be configured to form a nearly complete electronic power supply. Overall power supply volume can be maintained relatively small because of the brick's high-density, cost can be reduced since the bricks are mass-produced, and development time is reduced as less engineering is required.
A complete electronic power supply will typically require other functions beyond those that can be provided by bricks. Often fault detection and interface signals are required. The circuitry that provides these functions requires its own dedicated converter since the power supply's outputs may not be operating due to a fault condition or from being intentionally inhibited. This dedicated converter is sometimes referred to as a "housekeeping" converter or a "bias voltage" converter. It is often realized in the form of a flyback converter, since the flyback is the simplest form of isolated switch-mode DC-DC converter and is well suited for low power and wide input voltage range operation.
Another function often required by an electronic power supply is the ability to provide uninterrupted operation in the presence of transients in its voltage input. This circuitry may insure continued operation of the bricks despite a short term power interruption. It may also limit the voltage presented to the bricks to allow continued operation during a high voltage transient while preventing their damage or degradation.
There are a number of simple methods to provide energy storage that will facilitate continued operation of an electronic power supply when primary power is interrupted. One common method is to incorporate some form of battery backup. In many applications such as in military electronic equipment however, batteries are prohibited primarily due to maintenance issues and to a secondary degree, safety and disposal issues. One or more capacitors such as those produced by Cornell Dubilier Electronics, Inc., Wayne, N.J., offer the next best alternative to serve as the energy storage element. Charge control and discharge activation of these capacitors may be implemented in a number of ways to meet the needs of an uninterruptable power supply.
A typical realization of the prior art is shown in FIG. 1 and as in most cases, involves charging an energy storage capacitor 3 from the primary power source 5 through a series connected charge control circuit 7. Charge control circuit 7 is typically in parallel with an element that serves as a discharge element 11 to the load. Rectifier 13 comprises a single blocking diode in the case of a DC primary power source 5 or a rectifier bridge in the case of an AC primary power source 5. In either case, rectifier 13 will prevent the primary source 5 from discharging the capacitor 3 during a low voltage transient. Some form of charge limiting 17 is generally incorporated to prevent high surge current when primary power is first applied through a switch 15.
The charging circuit may be a simple resistor or a current source such as shown in FIG. 2. The charge current of the current source is determined based upon the voltage across resistor 21. The voltage across resistor 21 is the difference of the zener diode 23 voltage and the gate-source threshold voltage of Field Effect Transistor (FET) 25 during the charging interval. Resistor 27 provides bias current to the gate of FET 25.
Referring again to FIG. 1, during a low line transient rectifier 13 becomes reverse biased and the DC-DC converters are provided with energy from the capacitor 3 through diode 11. Upon restoration of input power, the capacitor 3 is recharged and energy is provided to the DC-DC converters by the primary power source 5. Zener diode 17 limits the voltage to capacitor 3 and is selected typically to limit the voltage to approximately the steady-state voltage level of the primary power source 5 and consistent with capacitor 3 voltage derating requirements. Storage voltage levels that incorporate high-voltage zener diodes 17 such as MIL-S-19500/406A for its control may vary by as much as 13% over their operating temperature range including the initial tolerances. An unfortunate aspect of these zener diodes is their positive temperature coefficient that causes the voltage to increase with temperature, opposite from that desired to compensate for reduced capacitance with decreasing temperatures. The maximum stored voltage that can be guaranteed is the minimum steady-state voltage of the primary power source. Although the prior art is simple, the volume of storage capacitance may be large due to the relatively low stored voltage level that can be achieved.
Barlage U.S. Pat. No. 5,168,436 is illustrative of a power supply that provides uninterrupted power during a short term power removal. This is implemented by providing a power supply with two primary windings for the transformer, and two associated switches operable to modulate current flow through the primary windings. One switch is regulated in a conventional manner during normal operation to enable and modulate current flow from a relatively low-voltage power source through the primary winding associated with that switch. A second switch is connected through the second primary winding to a relatively high-voltage capacitor, but is regulated to disable current flow from the capacitor through the winding during normal operation, and to enable and modulate the same during the holdup period. Barlage's invention provides a substantially glitch-free transfer from normal operation to holdup mode. Shortcomings of this method include greater complexity of the power supply transformer and no provision for high voltage limiting. Control of the storage capacitor voltage is not particularly accurate, requiring larger capacitor volume to ensure sufficient energy storage and remaining within capacitor voltage rating. There are also no apparent provisions for charging to higher voltage levels at low temperatures to compensate for reduced capacitance.
Other methods of reducing energy storage capacitor volume are based on extracting more energy from the capacitor. This may be implemented by interposing a second converter between the energy storage capacitor and the main power converter. The combined converters can maintain performance to a lower capacitor voltage and therefore more energy is extracted. Windes U.S. Pat. No. 5,214,313 illustrates a method that allows the energy storage capacitors to discharge down to a much lower voltage than would be possible if they were used to drive the load directly. This is accomplished by inserting a voltage regulator ahead of an inverter which is connected to the load. Lange et al U.S. Pat. No. 5,179,508 present a method whereby a "Standby Boost Converter" is combined with any type DC-DC converter to obtain an overall more efficient power supply and means by which more energy may be extracted from an energy storage capacitor. Windes' and Lange's methods are effective, however, they may not achieve the energy storage capacitor volume reductions that other methods storing voltages higher than maximum steady-state input voltage levels realize. No provisions are made for limiting maximum voltage presented to the power converters.
Several methods exist for limiting maximum voltage to a load such as DC-DC converters from a primary power source. This may be as simple as including a damped low-pass filter composed of resistors, inductors, and capacitors between the power source and load. This method does not provide accurate control of peak voltage, is very dependent on the duration of the transient, may impact stability, and may also require relatively large volume to implement. Semiconductor transient absorption devices such as metal oxide varistors (MOVs), although they exhibit very fast response times, do not accurately limit their peak voltages and performance is dependent upon the impedance of the primary power source. MOV's must be carefully selected to insure sufficient energy absorption capability to limit the worst case transients. Limiters based upon high voltage zener diodes suffer the same inaccuracies as discussed earlier for the energy storage capacitor voltage limiters.
It is an object of the present invention to provide a power supply that can deliver well-regulated, uninterrupted output voltages over a wide temperature range to a load when supplied from an input source having momentary voltage interruptions, while achieving a minimum volume of energy storage capacitance.
It is another object of the present invention to provide a power supply that can deliver well-regulated, uninterrupted output voltages to a load from an input source having wide transient variations while achieving overall power efficiency improvement.
It is yet another object of the present invention to provide a power supply that can deliver well-regulated, uninterrupted output voltages to a load from an input source having wide transient variations that is suitable for use with mass-produced high-density DC-DC converter modules.
It is still another object of the present invention to provide a power supply that can deliver well-regulated, uninterrupted output voltages to a load from an input source having wide transient variations by making effective use of an already existing housekeeping converter. No additional storage capacitor charging converter is required nor are significant changes to the housekeeping converter required.
It is another object of this invention to provide a means of accurately limiting maximum voltage presented to a load such as a DC-DC converter that is not dependent upon the primary power source impedance.
SUMMARY OF THE INVENTION
In one aspect of the present invention, six circuit functions are provided: a high voltage reference, holdup capacitor charger, input voltage transient limiter, energy transfer switch, high voltage bias provided by flyback converter, and holdup capacitor. The high voltage reference establishes an accurate, temperature-compensated charge limit for the holdup capacitor and a maximum voltage limit for the input voltage transient limiter. The holdup capacitor charger provides a voltage and current limited source to charge the holdup capacitor. The current limit for two distinct charge intervals may be set. Initially, holdup capacitor is charged to the input line voltage at a current not to exceed the allowable inrush current or the power limitation of a pass element. Completion of capacitor charge to levels determined by high voltage reference is set by source capability of high voltage bias. The input voltage transient limiter contains a pass element connecting the input line voltage to the conditioned power bus loaded with DC-DC converters, for example. This pass element normally in a saturated state becomes active at a voltage level determined by the high voltage reference to limit the voltage to the load on power bus during high input voltage transients. During a power interruption, energy transfer switch connects the holdup capacitors to the conditioned power bus. High voltage bias is obtained from an internal housekeeping supply and provides high voltage bias to the aforementioned circuits.
A means by which a power supply may be adapted to provide uninterrupted power during transients in its input voltage and limit the maximum voltage presented to the DC-DC converter portion of the power supply is provided. It makes effective use of an already present housekeeping supply, typically realized in the form of a flyback converter. This invention requires no additional windings to the transformer, makes use of otherwise wasted transformer leakage energy, and allows for more efficient design of the flyback converter since its maximum input voltage is also limited. The more efficient design of the flyback converter is made possible by the narrower input voltage range over which the converter is required to operate, allowing advantageous adjustment of the flyback converter transformer turns ratio. Since the energy storage capacitor stores accurately-controlled, adjustable, relatively high voltage, that tends to increase with decreasing temperature, capacitor volume can be minimized. Since there is provision to limit the maximum voltage seen by the DC-DC converters, these converters may be designed to operate more efficiently and/or designed to operate down to a lower input voltage level thereby enabling more energy to be extracted from the energy storage capacitors, facilitating further capacitor volume reduction. Alternatively, this invention can allow the use of lower-cost bricks with narrower input voltage range to configure an uninterruptable electronic power supply. This has become more important recently as the military seeks commercial-off-the shelf (COTS) low-cost solutions to their power needs.
BRIEF DESCRIPTION OF DRAWINGS
The nature of the invention, as well as other objects and advantages thereof will become more apparent to those skilled in the art after considering the following detailed description in connection with accompanying drawings in which like reference numerals indicate like elements throughout, wherein:
FIG. 1 is an electrical schematic of an example of the prior art illustrating an energy storage circuit that is charged directly from the line voltage;
FIG. 2 is an electrical schematic of an example of the prior art illustrating a current source charge control circuit;
FIGS. 3A and 3B are an electrical schematic diagram of the uninterruptable power supply according to the preferred embodiment of the present invention;
FIG. 4 is an electrical schematic of a typical implementation of input voltage sense and required drive for the energy transfer function; and
FIG. 5 is an electrical schematic illustrating modification of the input voltage transient limiter to increase its power handling capability.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing, and more particularly FIG. 3 thereof, six major functions are schematically illustrated: the high voltage reference 31, the holdup capacitor charger 33, the transient voltage limiter 35, the energy transfer switch 37, the flyback converter 41 generating the high voltage bias 65 and the holdup capacitor 43. The functions receive input power from an input power source 51 and develop conditioned power at bus 45.
Input power source 51 is connected to input voltage bus 53 that provides power to the input transient voltage limiter 35. Input voltage limiter 35 includes a diode 47, having its anode connected to input power source 51 via input voltage bus 53 and its cathode connected through a resistor 55 to the gate of a pass element shown as an n-channel MOSFET 57. The cathode of diode 47 is also connected to the drain of MOSFET 57. A diode 61 has its anode connected to the gate of MOSFET 57 and its cathode connected to the cathode of a zener diode 63. The anode of zener diode 63 is connected to the source of MOSFET 57 and conditioned power bus 45. The input transient voltage limiter 35 has the gate of MOSFET 57 connected to a high voltage bias supply 65 through a series connected resistor 67 and diode 71, with the anode of diode 71 connected to the high voltage bias supply 65 and the cathode of diode 71 connected to resistor 67. The input transient voltage limiter 35 also includes a zener diode 73 having its cathode connected to the gate of MOSFET 57 and its anode connected to the anode of blocking diode 75.
The high voltage reference 31 is connected to the high voltage bias supply 65 through a diode 77. The anode of diode 77 is connected to high voltage bias supply 65 and the cathode is connected to the collector of npn transistor 81. Connected between the collector and base of transistor 81 is a current regulator diode 107, with the cathode of current regulator diode 107 connected to the base of transistor 81. The emitter of transistor 81 is connected through series connected variable resistor 83 and resistor 85 to ground. The base of a pnp transistor 87 is connected to the junction of variable resistor 83 and resistor 85. The base of transistor 81 and the emitter of transistor 87 are connected through series connected diode 91 and zener diode 93. Although only one diode 91 is shown, several diodes can be connected in series to increase the amount of temperature compensation as required. The anode of diode 91 is connected to the base of transistor 81 and the anode of zener diode 93 is connected to the emitter of transistor 87. The collector of transistor 87 is connected to ground through series connected resistor 95 and zener diode 97. The anode of zener diode 97 is connected to ground.
The holdup capacitor charger 33 includes a diode 101 having its cathode connected to the emitter of transistor 87 and the cathode of blocking diode 75. The anode of diode 101 is connected to the gate of a pass element shown as an n-channel MOSFET 103. A diode 105 has its anode connected to the conditioned power bus 45 and its cathode connected to the drain of MOSFET 103. The cathode of diode 105 is also connected through a resistor 106 to the anode of a current regulator diode 107 and through a resistor 111 to the gate of MOSFET 103. The source of MOSFET 103 is connected through a resistor 113 to the anode of a blocking diode 115. The anode of diode 115 is also connected to the anode of zener diode 117. The cathode of zener diode 117 is connected to the gate of MOSFET 103. The cathode of blocking diode 115 is connected to the positive plate of holdup capacitor 43. The negative plate of holdup capacitor 43 is connected to ground. While one holdup capacitor is shown, several series connected or parallel capacitors may be used to obtain the desired voltage rating or capacitance.
Energy transfer switch 37 has the anode of a diode 121 connected to the positive plate of holdup capacitor 43. The cathode of diode 121 is connected through a switch shown as an n-channel MOSFET 123 to the conditioned power bus 45. The conditioned power bus provides uninterrupted power during transients in voltage in the input power source 51 to a load 181, that may be a switching power converter or other load requiring uninterrupted power during transients in the primary power supply. The drain of MOSFET 123 is connected to the cathode of diode 121 and the source of MOSFET 123 is connected to the conditioned power bus 45. A drive circuit 125 that senses the voltage at input voltage bus 53 and is connected to the base of npn transistor 127, is shown in more detail in FIG. 4. High voltage bias supply 65 is connected through a resistor 131 to the base of transistor 127 and is connected through a resistor 133 to the collector of transistor 127. A zener diode 135 is connected across the collector and emitter of transistor 127, with the anode connected to the emitter. The collector of transistor 127 is connected to the gate of MOSFET 123.
A flyback converter 41 has a switch shown as an n-channel MOSFET 137, having its drain connected in series with the undotted side of the primary winding of a transformer 141. The source of MOSFET 137 is connected to ground and the gate is driven by a current mode pwm controller 143. The dotted end of the primary winding of transformer 141 is connected to the conditioned power bus 45. The drain of MOSFET 137 is connected to the anode of diode 145 and a cathode 145 to the high voltage bias supply 65. A capacitor 147 is connected between the conditioned power bus 45 and the high voltage bias supply 65. The secondary of transformer 141 has the dotted end of the secondary winding connected to ground and the undotted end of the secondary winding connected to the anode of a diode 151. The anode of diode 151 is connected to the regulated output voltage of the flyback converter 153. A capacitor 155 is connected between the cathode of the diode 151 and ground.
Referring now to FIG. 4, an implementation of the driver 125 is shown. Resistors 157 and 161 are connected in series between the input voltage bus 53 and ground. The noninverting input of a comparator 163 is connected to the junction of resistors 157 and 161. The inverting input of the comparator is connected to a voltage reference. The output of the comparator 163 is connected through a resistor 165 to the LED emitter portion of an opto-coupler 167 to a bias voltage. The photodetector portion of the opto-coupler is connected between the base of transistor 127 and the conditioned power bus 45.
Referring now to FIG. 5, an alternative embodiment of the input voltage transient limiter 35 is shown as input voltage transient limiter 35'. Input power source 51 is connected to input voltage bus 53 that provides power to the input transient voltage limiter 35'. Input voltage limiter 35' includes a diode 47, having its anode connected to input power source 51 via input voltage bus 53 and its cathode connected to the drain of an n-channel MOSFET 57. The input transient voltage limiter has the gate of MOSFET 57 connected to a high voltage bias supply 65 through a series connected resistor 67 and diode 71, with the anode of diode 71 connected to the high voltage bias supply and the cathode of diode 71 connected to resistor 67. A diode 61 has its anode connected to the gate of MOSFET 57 and its cathode connected to the cathode of a zener diode 63. The input transient voltage limiter 35' also includes a zener diode 73 having its cathode connected to the gate of MOSFET 57 and its anode connected to the gate of blocking diode 75. A second FET in the input voltage transient limiter 35', shown as an n-channel MOSFET 171, has its drain connected through a power resistor 173 to the drain of MOSFET 57. The gate of MOSFET 171 is connected to one end of resistor 175. The other end of resistor 175 is connected to the junction of diode 71 and resistor 67. The cathode of zener diode 177 is also connected to the gate of MOSFET 171. The anode of zener diode 177 is connected to the cathode of zener diode 73. The source of MOSFET 171 is connected to the source of MOSFET 57 and the conditioned power bus 45.
The operation of FIGS. 3A and 3B is as follows, the high voltage reference 31 utilizes high voltage bias 65 developed from flyback converter 41. Current regulator diode 107 establishes a constant current in temperature compensated zener diode 93 developing a stable voltage across the zener diode 93. The base of transistor 81 requires relatively little current due to its high gain. Variations of zener diode current with temperature are relatively small. The sum of the voltages across zener diode 93 and diode(s) 91 is impressed across variable resistor 83. The base-emitter voltages of transistors 81 and 87 offset one another over temperature. Diodes 107, 91, 93, transistors 81, 87, and variable resistor 83 in effect form a current source delivering current through resistor 85. The current provided by the current source will vary with temperature determined by the sum of the voltage drops across diodes 93 and 91. Since transistor 87 is high gain, its base will supply relatively small current compared with that of the current source resulting in a voltage across resistor 85 that will track the current provided by the current source. The high voltage reference is taken from the emitter follower connected transistor 87 at node 50 that serves to buffer the reference from its loads 33 and 35. Favorable temperature variation of the reference is provided by the temperature coefficient of diode(s) 91. As temperature decreases, the forward voltage of diode(s) 91 increases, resulting in increased current from the current source, higher voltage across resistor 85 and higher reference voltage at node 50. This takes advantage of the capacitor's 43 ability to support higher voltage at colder temperature. Variable resistor 83 may be adjusted to trim out initial circuit tolerances. Resistor 95 and zener diode 97 reduce the voltage across the collector-emitter of transistor 87 and compensate for variations in load current in the path of diode 101. Resistor 95 and zener diode 97 also reduce power dissipation experienced by transistor 87 by reducing the voltage across its collector-emitter terminals. The necessity of resistor 95 and zener diode 97 is dependent upon the particular application.
The input transient voltage limiter 35 consists of pass element 57 operating in a saturated state under nominal input conditions. Its gate voltage is provided by the high voltage bias circuit 65 via diode 71 and resistor 67. Upon application of input source 51, prior to establishment of high voltage bias 65, gate voltage is provided via resistor 55. The voltage on conditioned power bus 45 is limited by zener diode 73 and blocking diode 75 establishing a clamp level at the gate of FET 57. The clamp level is approximately the sum of the high voltage reference at node 50 and voltage across diodes 73 and 75 minus the gate-source threshold voltage of FET 57. Zener diode 73 is provided since the input voltage clamp level on power bus 45 will typically be set higher than the voltage on the holdup capacitor 43. As power source 51 rises above this clamp level, FET 57 will transition to a linear state absorbing the transient energy and thereby limiting the maximum voltage seen on conditioned power bus 45. Care must be taken to remain within the safe operating area (SOA) of FET 57. FIG. 5 illustrates one method in which the power absorption capability of the transient voltage limiter may be increased. Diodes 61 and 63 limit the gate-source voltage of FET 57 to within its ratings during normal operation.
The holdup capacitor charger 33 sets two different rates of charge for holdup capacitor 43. At application of input power source 51, the majority of charge current is via FET 57 and diode 105 and is limited by a current source formed by FET 103, resistors 113 and 111 and zener diode 117, much as described in the prior art. Current is limited so as not to exceed specified inrush current limitations or SOA of the FET 103. When holdup capacitor 43 reaches the voltage level of the input power source, the charge rate via diode 77 is further limited by resistor 106 to within the capability of the high voltage bias 65. With the gate of pass element FET 103 clamped to the high voltage reference, as the holdup capacitor 43 approaches this level the pass element will be choked off limiting the charge current. Resistor 111 provides gate voltage for FET 103 while zener diode 117 limits gate-source voltage during the charging interval. Blocking diode 115 prevents holdup capacitor 43 from discharging into charger or reference circuits.
The energy transfer function 37 utilizes FET 123 as a switch to connect the holdup capacitor 43 to the conditioned power bus 45 when it is sensed the input power source 51 is falling below an acceptable limit. Bias for this function is provided by high voltage bias supply 65. The input voltage bus 53 is sensed for voltage drops below minimum steady-state limits and this information is used to drive the base of transistor 127. Typical implementation of this sense circuit is contained in FIG. 4. Note that drive for transistor 127 must be referenced to conditioned power bus 45. As shown in FIG. 4, this is realized with an opto-coupler 167. Diode 121 prevents current flow from conditioned power bus 45 through the body diode of FET 123 prior to complete charge of holdup capacitor 43. Zener diode 135 limits gate-source voltage applied to FET 123.
The high voltage bias 65 is derived from an existing flyback housekeeping supply 41. Detailed discussion of flyback converter 41 will not be undertaken since its operation is standard and well documented. Turns ratio of flyback transformer 141 and regulated output voltage 153 determine the magnitude of the high voltage bias. The high voltage bias is typically 20-50% greater than the nominal input power supply 51 voltage. Flyback control 143 is maintained by current mode PWM controller, such as Linear Technology LT1242.
Table 1 contains numerical estimates of performance to understand the type of energy storage volume reductions that may be realized. Three cases are considered where a fixed holdup time is required over a wide temperature range. Capacitor volume is considered to be approximately proportional to the product of capacitance and the capacitor rated voltage. In each case, the DC-DC converters are assumed capable of operating down to 125 volts DC. The capacitor considered has a capacitance 3200 microfarads nominal at room temperature and a capacitance reduced by 20% at cold temperatures. The required capacitor voltage derating is 0.7 times the rated voltage. Case 1 describes a prior art off-the-line energy storage capacitor charger. The capacitor is rated at 350 volts and therefore is derated to 245 volts that establishes the highest acceptable nominal initial capacitor voltage allowed. It is assumed that the voltage is controlled to within 13% by a high voltage zener. The guaranteed energy that can be provided is approximately 38.2 Joules. The nominal capacitor-voltage (CV) product is 1.12 volt-farads. Case 2 describes a high voltage storage that is again controlled by a 13% zener. The capacitor is rated at 500 volts and therefore is derated to 350 volts that again establishes the acceptable nominal initial capacitor voltage. To guarantee that the same amount of usable energy is stored as in Case 1, the nominal capacitance must be 1240 microfarads yielding a CV product of 0.62 volt-farads. Case 3 describes the preferred embodiment of this invention that incorporates an accurate high voltage reference and a 500 volt capacitor. The reference is designed to increase the capacitor voltage by 10% when the temperature is at a minimum. In this case, the required capacitance to guarantee 38.2 Joules is 720 microfarads yielding a CV product of 0.36 volt-farads. The following table summarizes the results. Significant reduction in capacitor volume is realized by storing higher voltage and further significant gains are realized by incorporating an accurate, temperature compensating voltage reference to limit voltage on the storage capacitor.
TABLE 1______________________________________ % Change in volume Nom. Voltage CV from pre-Case Description Cap Rating Product vious case______________________________________I Off-line charge 3200 μF 350 V 1.12 V-F notInaccurate limiter applicableII High voltage charge 1240 μF 500 V 0.62 V-F -44.6 %Inaccurate limiterIII High voltage charge 720 μF 500 V 0.36 V-F -42.0 %Accurate, temperature-correcting limiter______________________________________
There are various changes in form and detail that may be made to the preferred embodiment of the present invention. For those skilled in the art, it will be understood that the high voltage bias may be generated from any converter which makes available from its transformer elements a voltage that is substantially higher than the nominal input voltage from the primary power source. This converter is not required to be the housekeeping circuit but instead may be a DC-DC converter producing the power supply outputs.
The high voltage reference may be modified in other ways to provide the desired performance with temperature. The preferred embodiment demonstrated a means where the temperature performance was controlled by means of diodes 91 and 93. Alternative methods to achieve temperature performance may be through the use of a network of fixed and temperature dependent resistors such as are commonly known as thermistors. Since the values of resistors 83 and 85 strongly determine the reference voltage, their location would provide suitable places to incorporate thermistor-based networks.
It is also understood that one may elect not to take advantage of the preferred embodiment of the high voltage reference. The voltage limiter of the prior art may be used in its place or a reference based upon a precision programmable reference such as a TL431 from Texas Instruments. Data books and application notes illustrate a variety of regulators and current sinks which may be useful for energy storage capacitor voltage limiting and charge control.
The input voltage transient limiter may be modified to increase its power absorption capability. When approaching SOA limitations of FET 57, due to increased loading on conditioned power bus 45, a second FET 171 with power resistor 173 may be added as shown in FIG. 5. Resistors 175 and 173, FET 171 and zener diode 177 have been added to the previous embodiment. For heavy current loading on conditioned power bus 45, FET 57 limits the voltage as previously described. FET 171 is in a saturated state as its gate is being driven via resistor 175 and limited in voltage by zener 177 to a level below FET 171 gate-source breakdown voltage level. Since FET 171 is saturated, high power resistor 173 is in parallel with FET 57 reducing its dissipated power and increasing the overall dissipation capability of the limiter. For lighter current loading on conditioned power bus 45, FET 57 can no longer limit the voltage since the current provided via FET 171 and resistor 173 is greater than that required by the load. The maximum conditioned power bus 45 voltage increases by the amount of the zener 177 voltage limited by FET 171 in the same manner as discussed earlier. The crossover between the operation of the FETs 57 and 171 may be approximately determined by when the load current drawn on conditioned power bus 45 is equal to the current determined by resistor 173 and the difference of the voltage at input voltage bus 53 and the maximum limit on conditioned power bus 45.
It is also understood that one may choose not to include the transient voltage limitation feature 35 of this invention. None of the remaining five circuit functions are dependent on this feature. In situations where the input power source is well behaved this circuit may not be required. Alternatively, the voltage transient limiter 35 feature may be implemented without the need for holdup capacitor charger 33 and capacitor 43.
The foregoing has described a power supply that can deliver well-regulated, uninterrupted output voltages over a wide temperature range to a load when supplied from an input source having momentary voltage interruptions, while achieving a minimum volume of energy storage capacitance.
While the invention has been particularly shown and described with reference to several embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
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An electronic power supply is adapted to provide uninterrupted power during transients in a voltage input received from a primary power source. The volume of the required storage element is significantly reduced. Adaptations are also made to limit the maximum voltage presented to the voltage converter portion of the electronic power supply by the primary power source. Beneficial adjustment to the turns ratio of the voltage converter transformer and use of lower voltage-rated, more energy efficient power semiconductors result. The voltage levels of the energy storage element and the voltage limiter are very accurate, allowing critical power supply components to be used close to their allowable limits. Density and efficiency of an uninterruptable electronic power supply are both increased.
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TECHNICAL FIELD
[0001] The present disclosure generally relates to medical devices for use in correcting foot deformities, and methods for surgically installing such devices and correcting such deformities.
BACKGROUND
[0002] Bunions have long been one of the more common types of painful foot deformities. The technical name for this type of deformity is Hallux Abducto Valgus (HAV), which is generally described as a medial deviation of the first metatarsal accompanied by a lateral deviation and/or valgus rotation of the hallux (or “big toe”). The result effect is a subluxation of the big toe joint (or first metatarsophalangeal joint (MTPJ)) creating a boney prominence (or eminence) on the inside of the foot, near the base of the big toe. FIG. 1A illustrates the normal anatomical configuration of a left human foot, which includes the first metatarsal 10 that extends between the medial cuneiform 12 and the hallux 13 . The first metatarsal 10 articulates with the medial cuneiform 12 at the first metatarsocuneiform joint 14 at its most proximal aspect; and is further connected to the hallux 13 at the metatarsophalangeal joint 15 at its most distal aspect. Located adjacent (lateral) to the first metatarsal 10 is the second metatarsal 16 , which articulates with the intermediate cuneiform 17 at the second metatarsocuneiform joint 18 . The joint between the medial cuneiform 12 and intermediate cuneiform 17 is the intermetatarsocuneiform joint 18 . The sesamoids 19 are located beneath (plantar to) the first metatarsal head at the first MTPJ, and articulates with the head of the first metatarsal.
[0003] FIG. 1B illustrates the resulting anatomical configuration of a human foot experiencing HAV. In particular, the first metatarsal 10 extends from the medial cuneiform 12 and deviates medially while the hallux 13 deviates laterally. As a result, the sesamoids 19 may rotate with the first metatarsal 10 . This condition may lead to painful motion of the big toe joint and/or difficulty fitting footwear. Other conditions associated with HAV may include: hammer toe formation of the adjacent toes, forefoot pain on the ball of the foot (aka metatarsalgia), stress fractures of the adjacent metatarsals, flat feet (pes planus), and arthritis of the first MTPJ or midfoot.
[0004] Bunions may occur from a variety of causes, such as genetic factors, gender influences, biomechanical and structural causes, trauma (injury), and certain shoes. Some physicians believe genetics play a large role in the development of bunions. Dudley Morton suggested that bunions may be a result of evolutionary influence, and described a certain foot type that is associated with bunions—the so called Morton's foot (a condition where the first metatarsal is shorter than the other metatarsals. See Morton D J. The Human Foot: Its evolution, Physiology and functional Disorders. Columbia University Press, Morningside Heights, N.Y., 1935. Some people develop bunions when associated with a condition called hypermobility, where the midfoot (i.e., metatarsocuneiform joint or “MCJ,” illustrated in FIG. 1A as the joint defined at the meeting of the metatarsal 10 and the cuneiform 12 ) exhibits excessive motion. Less commonly, malshaped bones (hallux and/or first metatarsal) may give the appearance of and/or cause bunions. Many physicians attribute the progressive development of bunions to high heel and pointy toe shoes more commonly worn by women. It is well known that women are more likely to develop bunions than men.
[0005] Surgeons use weightbearing radiographs to determine the severity of HAV in an attempt to quantity the deformity, and aid in surgical decision making. The most commonly utilized radiographic measurement is the intermetatarsal angle (IMA), which measures the angle between a longitudinal bisection of the first and second metatarsal shafts. The IMA essentially measures the extent with which the first metatarsal has deviated (medially) from the second metatarsal. The normal value for the IMA is less than 8 degrees. Another useful radiographic measurement is the hallux abductus angle (HAA), which measures the amount of lateral deviation of the big toe (hallux). The HAA essentially measures the extent with which the hallux has deviated (laterally) from its native position (nearly rectus with the more proximal metatarsal). The normal value for the HAA is less than 12 degrees. A patient with a mild HAV deformity may have an IMA of 10-12 degrees and an HAA of 21-30 degrees. A patient with a moderate HAV deformity may have an IMA of 12-16 degrees and an HAA of 31-40 degrees. A patient with a severe HAV deformity may have an IMA of greater than 16 degrees and an HAA of greater than 40 degrees.
[0006] Various techniques have been developed to surgically correct HAV. The most basic technique simply involves resecting any enlarged bone at the medial aspect of the first metatarsal head, but this approach is typically used in conjunction with other more advanced techniques. A common technique involves an osteotomy (bone cut) procedure in which the first metatarsal is broken into two pieces and the distal portion of the bone is translated closer (medially) to the adjacent second metatarsal. The osteotomy may be performed at several locations on the first metatarsal, depending on the severity of the deformity. Less severe HAV deformities are typically corrected with an osteotomy near the head ( 10 a in FIG. 1 ) of the first metatarsal, whereas moderate and larger deformities are corrected with an osteotomy near the base ( 10 b in FIG. 1 ) of the first metatarsal. Whichever osteotomy technique is utilized, only the distal portion of the first metatarsal is relocated into a more lateral position while the proximal segment position remains unchanged. It should be understood that any osteotomy procedure reorients the first metatarsal by changing its shape from that of a straight bone to a more curved bone.
[0007] Alternative techniques have been developed that do not require breaking of the bone, or changing the natural shape of the first metatarsal. One such technique calls for fusion of the MCJ, wherein the entire first metatarsal is relocated into a corrected position. This approach was originally developed by Dr. Paul Lapidus, and hence this particular technique is often referred to as the Lapidus approach (or Lapidus Bunionectomy or Lapidus Arthrodesis or Modified Lapidus Bunionectomy/Arthrodesis). In some situations the procedure may involve an isolated fusion of the 1 st MCJ, and in other situations surgeons may also incorporate a fusion of the intermediate cueniform area and or 2 nd metatarsal base. In general, the idea behind the Lapidus approach is to permanently fuse the base of the first metatarsal to the medial cuneiform bone in a corrected new position. This permanent fixation is carried out by first reducing the IMA and then fusing the MCJ. Implementation of this approach often involves the use of a number of screws across the joint or a plate that can accommodate screws to attach the plate to the metatarsal and medial cuneiform. In some cases, a fusion of the 1 st MCJ that incorporates lengthening of the entire segment by adding bone graft (i.e., a block of bone) into the fusion site is better termed a distraction Lapidus.
BRIEF SUMMARY
[0008] The present disclosure generally relates to an improved fixation or “Lapidus” plate for use in treating HAV deformities or other conditions that may call for a fusion of this joint and possibly concomitant fusion incorporating the 2 nd metatarsal base and/or intermediate cuneiform. The term “Lapidus” as used herein is only meant to be descriptive in terms of a suggested use for the plate and does not confer any structural limitations on the plate described herein. In one exemplary embodiment, the Lapidus plate is used for joint arthrodesis at the first MCJ. The Lapidus plate according to the present disclosure provides mechanical stability of the first metatarsal while also accommodating and assisting reorientation of the first metatarsal to correct the HAV deformity. In one embodiment, the plate is generally elongated and comprises a thin and rigid stabilizing member of biocompatible material. The orientation of the fixation plate offers multiplanar stability including the plantar aspects of the joint to resist tensile forces transmitted across the fusion site. The screw configuration of the plate can be maintained for several different sizes of the plate while still maintaining desired multiplanar stability. Also, the positioning of the screw holes are designed to avoid invasion of the fusion site by the screws that ultimately pass therethrough. Indeed, the screw angles are designed for the post-Lapidus position.
[0009] The Lapidus plate according to the present disclosure includes additional features that accommodate the desired reorientation of the first metatarsal during correction. For example, the Lapidus plate described herein includes a degree of twist along its longitudinal axis to follow the contour of the first metatarsal and medial cuneiform, thereby facilitating reorientation of the first metatarsal to its natural position. The Lapidus plate is further anatomically configured to include a recess, which accommodates the natural crests of the medial cuneiform and the first metatarsal. In this manner, the first metatarsal can be guided against the medial cuneiform and the plate such that the base of the first metatarsal fits within the recess. The recess thus facilitates a desired location and orientation of the first metatarsal that approximates its natural position. In this manner, the Lapidus plate according to the present disclosure accommodates the final position of the fusion of the MCJ. The fixation plate is anatomically configured to provide rigid support of the realigned MCJ fusion site while positioning screws to avoid invasion into the fusion site thus achieving desired stability. It is to be appreciated that the plate described herein can be adapted for use on both right and left feet with a right foot plate being a mirror-image of a left foot plate.
[0010] A surgical method for preparing the MCJ for receipt of the Lapidus plate and subsequently implanting the plate is further described. In patients with HAV, surgical procedures may be concomitantly performed near the first metatarsal head. A capsular release of the first MTPJ and resection of the medial eminence, if present, is often performed in conjunction with release of the adductor tendon and lateral sesamoidal ligament. Next, all cartilage is removed from the first MCJ with either a reciprocal saw and/or manual resection. Removal of the cartilage is preferred to allow for bone on bone contact to allow for a fusion between the medial cuneiform and first metatarsal. The first metatarsal is then repositioned back to its native position (IMA as close to zero as possible). However, in order to compensate for the shortening that occurs with removal of the cartilage of the first MCJ, the first metatarsal must be translated inferiorly and/or angulated inferiorly (plantarflexed) to restore the weightbearing mechanics of the first metatarsal head at the ball of the foot. Lastly, the fusion site is stabilized with the fixation plate described herein. In some embodiments, the plate is placed on the dorsal medial surface of the segment to avoid contact with muscular attachments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Reference is now made to the following descriptions taken in conjunction with the accompanying drawings.
[0012] FIG. 1A illustrates a top view of a human foot;
[0013] FIG. 1B illustrates a top view of a human foot experiencing the condition of Hallux Valgus;
[0014] FIG. 2 illustrates a top view of a fixation plate according to one embodiment of the present disclosure;
[0015] FIG. 3A illustrates a side view of the fixation plate of FIG. 2 ;
[0016] FIG. 3B illustrates a side view of the fixation plate of FIG. 2 positioned adjacent to the MCJ;
[0017] FIG. 4 illustrates a schematic view depicting the gradual twist of the fixation plate of FIG. 2 ;
[0018] FIG. 5A illustrates a perspective view of the fixation plate of FIG. 2 positioned against the medial cuneiform and first metatarsal;
[0019] FIG. 5B illustrates another perspective view of the fixation plate of FIG. 2 positioned against the medial cuneiform and first metatarsal;
[0020] FIG. 6 illustrates a top view of the fixation plate of FIG. 2 affixed to the medial cuneiform and first metatarsal;
[0021] FIG. 7 is a bottom perspective view of the fixation plate of FIG. 6 showing the orientation of the screws; and
[0022] FIG. 8 is a perspective view of another embodiment of the fixation plate wherein the plate is a distraction plate.
DETAILED DESCRIPTION
[0023] Various aspects of a Lapidus plate and methods of using same according to the present disclosure are described. It is to be understood, however, that the following explanation is merely exemplary in describing the devices and methods of the present disclosure. Accordingly, several modifications, changes and substitutions are contemplated.
[0024] A Lapidus plate 20 for a human left foot according to the present disclosure is illustrated in FIG. 2 . It is to be appreciated that a Lapidus plate according to the present disclosure for a human right foot would be substantially similar to and have a mirror image configuration of the plate 20 illustrated in FIG. 2 . The plate 20 generally comprises a distal portion 22 for attachment to a metatarsal and a proximal portion 24 for attachment to a cuneiform. For purposes of illustration only, the distal and proximal portions 22 , 24 are divided along a joint axis (J) generally corresponding to the fusion site (i.e., the interface between the cuneiform and metatarsal) as will be described. In one exemplary embodiment, the metatarsal is the first metatarsal 10 ( FIG. 1 ) and the cuneiform is the medial cuneiform ( FIG. 1 ). The plate 20 is sized and shaped to conform to the anatomical contours of the first MCJ and as such the distal portion 22 includes a relatively narrow and rounded end portion 26 . The distal portion gradually increases in width along a first side 28 of the plate towards the proximal portion 24 . The proximal portion 24 includes a slight gradual increase in width along the first side 28 of the plate 20 culminating in a rounded end portion 30 that is larger in width than the end portion 26 of the proximal portion 22 . The plate 20 further includes a substantially linear second side 32 opposite the first side 28 .
[0025] The plate is configured and designed to avoid tendon and minimize soft tissue irritation, while also providing for optimal rigidity and stability. As such, in some embodiments, the end portion 26 of the distal portion 22 has an anatomically optimal width W 1 in the range of 10.5+/−3 mm, while the end portion 30 of the proximal portion 24 has an anatomically optimal width W 2 in the range of 16+/−4 mm. In some embodiments, the plate has a varying thickness of between 0.75 mm and 3.0 mm, thus minimizing tissue irritation. Moreover, the edges of the plate may be tapered. In one embodiment, the Lapidus plate according to the present disclosure is sized and shaped for placement in a “safe zone” of the area to be treated; that is, the place on the dorsal medial surface of the first metatarsal and medial cuneiform that is devoid of tendon attachments. It is to be appreciated that the Lapidus plate according to the present disclosure may have a configuration different than that described herein so long as the plate accommodates the contours of the particular anatomical region being treated.
[0026] The distal and proximal portions 22 , 24 of the plate 20 each include a plurality of screw holes formed therethrough to facilitate attachment of the plate to the respective metatarsal and cuneiform. In one embodiment, the distal portion 22 includes four screw holes formed through the plate 20 with two holes 40 , 42 being positioned in proximity to the joint axis J and the remaining two holes 44 , 46 being positioned distal of holes 40 , 42 . In some embodiments, the holes 40 , 42 and 46 are countersunk and threaded to accommodate screws having threaded heads as will be described. Hole 40 is positioned adjacent to the second side 32 and the joint axis J while hole 42 is positioned distal of hole 40 and closer to side 28 of the plate 20 . Hole 44 is positioned distally of holes 40 , 42 and is generally elongated to accommodate movement of the plate 20 as will be described. The elongated nature of hole 44 defines a pair of substantially parallel sides 47 , 49 , which are substantially parallel to second side 32 of the plate 20 . Hole 46 is positioned distal of hole 44 and also accommodates a screw (not shown) to assist with fixation of the plate 20 to the metatarsal. The location of hole 46 assists with distributing weight away from the fusion site.
[0027] Similar to the distal portion 22 of the plate 20 , the proximal portion 24 includes a plurality of screw holes to accommodate fixation. In one embodiment, the proximal portion 24 of the plate 20 includes three holes 48 , 50 and 52 formed therethrough. In some embodiments, the holes 48 , 50 and 52 are countersunk and threaded to accommodate screws having threaded heads as will be described. Hole 48 generally corresponds to hole 40 of the metatarsal portion, and as such, is positioned adjacent to the second side 32 and the joint axis J. Hole 50 generally corresponds to hole 42 of the metatarsal portion, and as such, is positioned proximal of hole 48 and closer to side 28 of the plate 20 . Hole 52 is positioned proximal of holes 48 , 50 and accommodates a screw (not shown) to assist with fixation of the plate 20 to the cuneiform bone. The location of hole 52 assists with distributing weight away from the fusion site.
[0028] In one embodiment, the holes 40 , 42 of the distal portion 22 and the holes 48 , 50 of the proximal portion are designed to assist with screw fixation into the widest part of both bone segments while maintaining a safe distance from the fusion site such that the screws that ultimately pass through such holes do not penetrate the fusion site. In this regard, the holes 40 , 42 , 48 and 50 form a substantially trapezoidal shape, which facilitates the even distribution of load across the MCJ. It is to be appreciated that the arrangement of holes 40 , 42 , 48 and 50 may not form an exact trapezoid. For example, the line defined from the centerpoint of hole 40 to the centerpoint of hole 48 and the line defined from the centerpoint of hole 42 to the centerpoint of hole 50 may not be perfectly parallel. Rather, such lines may be only substantially parallel and thus the arrangement of holes 40 , 42 , 48 and 50 may form a substantially trapezoidal shape rather than a true trapezoidal shape. The substantially trapezoidal arrangement of the holes 40 , 42 , 48 and 50 define an angle θ measured between the nonparallel sides of the trapezoid (i.e., between the lines A 1 and A 2 shown for purposes of illustration in FIG. 2 ). Also, the distance between the dorsal screw holes 40 , 48 is measured by the distance D. In some embodiments, the angle θ is optimally 57+/−15 degrees and the distance between the dorsal screws 40 , 48 is optimally 12+/−4 mm.
[0029] Referring to FIGS. 3A and 3B , the plate 20 according to the present disclosure further includes a recess 60 defined along a bone-contacting surface 62 of the plate. The recess 60 is generally defined at and adjacent to the joint axis J of the plate 20 . In this manner, the plate 20 is designed to accommodate the crests of the first metatarsal 10 and medial cuneiform 12 upon placement of the plate against the MCJ as illustrated in FIG. 3B . In some embodiments, a channel 64 is formed laterally in the bone-contacting side of the plate 20 in a region generally corresponding to the recess 60 to facilitate additional flexibility at the fusion site along the joint axis J ( FIG. 2 ). This flexibility assists the surgeon with bending of the plate 20 to achieve the desired final position of the plate at the fusion site.
[0030] In some HAV deformities, the first metatarsal experiences a lateral twist. As a result, the sesamoid bones are no longer in contact with the surface and are thus not able to carry most of the body load transferred through the forefoot during motion. This results in an extra load being placed on other adjacent metatarsals, thus increasing the possibility for metatarsalgia, or possibly stress fractures in those metatarsals. To correct this disorientation, in some embodiments, the plate 20 according to the present disclosure includes a degree of twist along its longitudinal axis (i.e., from end portion 30 to end portion 26 as shown in FIG. 2 ). Referring to FIG. 4 , the plate 20 has a gradual twist γ from proximal portion 24 to distal portion 22 . In some embodiments, the anatomically optimal twist is 12+/−6 degrees measured along the longitudinal axis of the plate 20 defined from end portion 30 to end portion 26 .
[0031] In practice, the first MCJ is prepared for plate implantation by first performing a capsulotomy of the ligaments surrounding the first MCJ and then removing cartilage within this joint. Referring to FIGS. 5A , 5 B and 6 , the proximal portion 24 of the plate 20 is placed against the medial cuneiform 12 and attached thereto using screws 70 having threaded heads and threaded shafts. The threaded heads of the screws 70 thread into the corresponding countersunk threaded holes 48 , 50 and 52 ( FIG. 2 ) such that the screws are fixed relative to the plate 20 . It is to be appreciated that in some embodiments, the screws may have non-threaded heads such that the screws are not locked into place relative to the plate 20 . Upon attachment of the plate 20 to the medial cuneiform 12 , the first metatarsal 10 is translated inferiorly in the direction I as illustrated in FIG. 5B to maintain a natural distribution of ground force over all the foot's sesamoid bones to avoid stress fracture or even breakage of the other four metatarsals. In some embodiments, the optimal amount of translation D I is 3+/−3 mm to accommodate for the shortening that occurs when cartilage is removed from the joint. The first metatarsal 10 is also translated laterally and rotated in the direction R to return the metatarsal to its approximate natural anatomic orientation to reduce the intermetatarsal angle. The plate 20 according to the present disclosure is designed for placement against the medial cuneiform and first metatarsal in an area devoid of muscular and tendinous attachments.
[0032] Upon proper positioning of the first metatarsal 10 , a screw (not shown) is placed through the elongated hole 44 and into the metatarsal with the elongation permitting movement of the bone. In some embodiments, the MCJ may be temporarily fixated in a corrected position using a k-wire. Also, the plate 20 may include k-wire holes such that k-wires can be used in conjunction with the plate to stabilize the first metatarsal for screw implantation. Upon stabilization, the first metatarsal 10 is then moved toward the medial cuneiform 12 whereupon the screw positioned through elongated hole 44 is tightened to compress the first MCJ. Once compression is achieved, the distal portion 22 of the plate 20 is further attached to the metatarsal using threaded screws 70 having threaded heads that are placed through screw holes 40 , 42 and 46 ( FIG. 2 ) and into the bone. The threaded heads of the screws 70 thread into the corresponding countersunk threaded holes 40 , 42 and 46 such that the screws are fixed relative to the plate 20 . It is to be appreciated that in some embodiments, the screws may have non-threaded heads such that the screws are not locked into place relative to the plate 20 . Once the plate is fixed to the medial cuneiform 12 and the first metatarsal 10 , the screw passing through elongated hole 44 may be removed.
[0033] Referring to FIG. 7 , the twist of the plate 20 along its longitudinal axis facilitates desired orientation of the screws into the metatarsal. More specifically, holes 40 and 42 are angled toward one another such that implantation of the screws 70 through these holes results in their axes crossing one another in a divergent manner. This, in turn, provides for optimal orientation of the screws 70 in the first metatarsal 10 to achieve desired stability.
[0034] A variation of the Lapidus plate according to the present disclosure involves providing for distraction (or lengthening) at the fusion site. As illustrated in FIG. 8 , this allows for bone graft 80 to be interposed between the 1 st metatarsal base 10 b and the medial cuneiform 12 , when the clinical situation arises. Providing for distraction at the fusion site maintains that the screw holes 40 and 42 purchase the 1 st metatarsal base 10 b, for which these holes are configured to provide maximal stability at the fusion site. The amount of distraction D′ most commonly required is between 1 mm-25 mm, with the distraction plate accommodating this length. It is to be appreciated, however, that other distraction lengths may be accommodated by the plate 20 of the present disclosure. In some embodiments, the plate 20 may add length by providing additional screw holes formed in distal portion 22 of the plate 20 . In some embodiments, fixation of the plate may occur via a screw passing through the fusion site into the intermediate cuneiform and/or second metatarsal.
[0035] The Lapidus plate 20 described herein and associated method of implantation leads to fusion of the MCJ, which provides for mechanical stability of the first metatarsal and medial cuneiform and the reorientation to compensate for an HAV deformity. The orientation of the fixation achieved according to the principles of the present disclosure offers multiplanar stability including the plantar aspects of the MCJ to resist tensile forces across the fusion site. The screw configuration described herein can thus be maintained for several different sizes of distraction Lapidus arthrodesis. That is, the screw configuration provides multiplanar stability as distraction length is added to the plate 20 .
[0036] While various embodiments of Lapidus plates and related methods of implanting such plates, have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the invention(s) should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. Moreover, the above advantages and features are provided in described embodiments, but shall not limit the application of the claims to processes and structures accomplishing any or all of the above advantages.
[0037] Additionally, the section headings herein are provided for consistency with the suggestions under 37 CFR 1.77 or otherwise to provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Specifically and by way of example, although the headings refer to a “Technical Field,” the claims should not be limited by the language chosen under this heading to describe the so-called technical field. Further, a description of a technology in the “Background” is not to be construed as an admission that technology is prior art to any invention(s) in this disclosure. Neither is the “Brief Summary” to be considered as a characterization of the invention(s) set forth in the claims found herein. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty claimed in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims associated with this disclosure, and the claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of the claims shall be considered on their own merits in light of the specification, but should not be constrained by the headings set forth herein.
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The present disclosure generally relates to fixation plates for use in correcting Hallux Valgus deformities under the Lapidus approach. The plate includes holes defined therethrough in such a way to facilitate multiplanar stability across the metatarsocuneiform joint. The plate is further sized and shaped to approximate the natural anatomic contour of the bone segments surrounding the metatarsocuneiform joint. Related methods for using the Lapidus approach to correct Hallux Valgus deformities are also described.
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FIELD OF THE INVENTION
The present invention relates to medical equipment generally and more particularly to apparatus for sensory and/or pain threshold measurement.
BACKGROUND OF THE INVENTION
There exist a number of known techniques for sensory threshold measurement in general and thermal threshold measurement in particular. These are described, inter alia in the following publications:
Goran A. Jamal et al "An Improved Automated Method for the Measurement of Thermal Thresholds. 1. Normal Subjects", Journal of Neurology, Neurosurgery and Psychiatry 1985; 48:354-360;
Clare J. Fowler et al "A Portable System for Measuring Cutaneous Thresholds for Warming and Cooling", Journal of Neurology, Neurosurgery and Psychiatry 1987; 50:1211-1215;
Dan Ziegler et al "Assessment of Small and Large Fiber Function in Long-term Type 1 (insulin-dependent) Diabetic Patients With and Without Painful Neuropathy" Pain, 34(1988) 1-10;
Claus D. Hilz et al "Thermal Discrimination Thresholds: A Comparison of Different Methods", Acta Neurol Scand 1990:81:533-540;
David Yarnitsky et al "Studies of Heat Pain Sensation in Man: Perception Thresholds, Rate of Stimulus Rise and Reaction Time", Pain, 40(1990) 85-91.
SUMMARY OF THE INVENTION
The present invention seeks to provide improved apparatus for measuring sensory or pain thresholds.
There is thus provided in accordance with a preferred embodiment of the present invention apparatus for measuring threshold sensitivity to a stimulus including sensory stimulation application apparatus for providing the stimulus to a subject, computer apparatus for governing operation of the sensory stimulation application apparatus and operator interface apparatus for interfacing between an operator and the computer apparatus. The computer apparatus and the operator interface apparatus including apparatus for enabling an operator to selectably apply the stimulus to a patient in accordance with any of the following protocols: method of limits; forced choice method; and staircase method. The threshold sensitivities are warm sensation, cold sensation, hot pain and cold pain.
Additionally, in accordance with an embodiment of the present invention, the computer apparatus and the operator interface apparatus includes apparatus for enabling an operator to selectably apply the stimulus to a patient also in accordance with either of the following protocols: Thermal Sensitivity Limen method and method of suprathreshold.
Further, in accordance with an embodiment of the present invention, the stimulus is temperature applied to a desired location on the subject's body and wherein the sensory stimulation application apparatus includes apparatus for changing the temperature.
Still further, in accordance with an embodiment of the present invention, the apparatus for changing the temperature can change the temperature at rates generally between 0.1° C./sec and 4° C./sec.
Moreover, in accordance with an embodiment of the present invention, the apparatus of the present invention also includes apparatus for performing age-normalized matching of results of a test.
Additionally, in accordance with an embodiment of the present invention, the apparatus of the present invention also includes apparatus for defining a new test protocol.
Furthermore, in accordance with an embodiment of the present invention, the apparatus for defining a new test application protocol include apparatus for defining desired parameters from among the following group of parameters: adaptation temperature, sensation or pain to be measured, rate of temperature change, number of trials per test, length of time between trials, manual or automatic triggering of the start of a next trial or test, providing sound at the start of a test, randomization of the order of trials and inclusion of catch trials.
Finally, in accordance with an embodiment of the present invention, the apparatus for defining a new test protocol includes apparatus for defining a default test or series of tests.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:
FIG. 1 is a generalized block diagram illustration of apparatus for measuring sensory and pain thresholds in accordance with a preferred embodiment of the present invention;
FIG. 2 is a detailed electrical schematic illustration of the apparatus of FIG. 1; and
FIGS. 3A, 3B and 3C are top and two side view illustrations, respectively, of a probe forming part of the apparatus of FIG. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Reference is now made to FIGS. 1-3, which illustrate apparatus for measuring sensory and pain thresholds in accordance with a preferred embodiment of the present invention. The apparatus comprises at least one probe unit 10, also called a thermode, including a Peltier cooling/heating element 12 such as the MI1023T-03AC manufactured by Marlow Industries, Inc. of the U.S.A., which receives electrical power via a power amplifier 14 and is cooled by a cooling unit 16. Associated with the Peltier cooling/heating element 12 are a cooling water temperature sensor 18, a probe temperature sensor 20 and, optionally, a skin temperature sensor 22, all of which communicate via an A/D converter circuit 24 and an input/output interface 26, with a computer 28 such as a conventional laptop computer. Optionally, communications devices can be subsituted for computer 28 for communication with a computer already owned by an operator.
The cooling unit 16 comprises a heat exchanger 30, and a heat sink 32, with associated fan 34 associated, as illustrated, with a Peltier cooling element 36. A circulation pump 38, which receives electrical power via a pump control circuit 40, which is in turn controlled by computer 28 via input/output interface 26, circulates cooling fluid through conduits 42 extending between the probe unit 10 and heat exchanger 30.
In addition to the circuitry described above, the laptop computer 28 also controls via the input/output interface 26, a printer selector 44, which passes output information from the computer 28 to either an internal printer 45 or to an external printer (not shown).
Laptop computer 28 also controls via the input/output interface 26, a patient input/output unit 46, which communicates with a patient interface unit 48, such as a unit with two switches on it.
Laptop computer 28 also controls via the input/output interface 26, a temperature watch dog circuit 50, which operates a pulse width modulation circuit 52 which provides power to the probe via amplifier 14.
It will be appreciated that the apparatus of the present invention is typically packaged in a generally small unit.
A power supply 54, provides the necessary electrical power inputs to the various elements of the apparatus. The circuitry of FIG. 1 is fully described in the schematic of FIG. 2. Verbal description of the circuitry is considered to be unnecessary and redundant.
The probe unit 10 is illustrated in detail in FIGS. 3A, 3B and 3C. The probe unit 10 typically comprises at least one Peltier element 60 to be located close to the skin of a patient, covered by a plate 62, typically manufactured of aluminum. Six Peltier elements 60 are shown in FIG. 3A.
Between the Peltier elements 60 and next to the plate 62 are typically located a the probe temperature sensor 20 and, optionally, the skin temperature sensor 22. Skin temperature sensor 22 is located beneath plate 62 which has a hole 64 in it through which sensor 22 sense the skin temperature.
Heat exchangers 66 are typically located above the Peltier elements 60 and are operative to provide a temperature differential across Peltier elements 60. In order to enable rapid cooling and heating of the Peltier elements 60, heat exchangers 66 are typically maintained at a generally constant temperature, such as 32° C., through the operation of cooling unit 16. The probe unit 10 is typically able to provide a rate of change of temperature in the range of 0.1° C./sec to 4° C./sec although other, greater rates of temperature change are also possible. The rates of change of temperature typically vary in steps of 0.1° C./sec.
The heat exchangers 66 and Peltier elements 60 are surrounded on three sides by insulation 68, such as rubber, for maintaining the temperature of the heat exchangers 66 and for providing a housing to probe unit 10.
A cap 70 is additionally provided for connection to attaching apparatus (not shown), such as a belt, for attaching the probe unit 10 to the body of the patient.
The apparatus of the present invention performs the following measurement protocols: method of limits, forced choice method, Thermal Sensitivity Limen (TSL) method, method of staircase, and method of suprathreshold, for measuring thresholds of sensation of warm and cold and thresholds of pain due to heat and due to cold.
It will be noted that, for all measurements, the stimulus intensity is heat or cold. In heat and cold tests, the subject is asked to indicate when he first feels or ceases to feel heat. For pain measurements, he is asked to indicate when he first feels or ceases to feel pain.
In the method of limits protocol, described by Yarnitsky et al which article is incorporated herein by reference, for each trial, a stimulus intensity (either hot or cold) is steadily increased, at a selectable rate, from a reference adaptation temperature, typically 32° C., until a patient indicates, through patient interface unit 48, a point of change in the temperature of the probe unit 10. The stimulus intensity is typically then decreased to the adaptation temperature until a new trial is begun. Typically, a number of trials are performed and the threshold to the stimulus is typically defined as the average intensity of the trials.
It will further be appreciated that the method of limits requires that probe unit 10 be able to relatively quickly change stimulus intensities.
In the forced choice method, described by Jamal et al which article is incorporated herein by reference, the apparatus of the present invention presents a trial comprising two time periods, during one of which a stimulus is present and during the second no stimulus is present. At the end of the trial, the patient is asked to choose during which of the two time periods he felt a stimulus. If he is correct, the computer 28 scores the trial as a Success (S), otherwise, a score of Failure (F) is stored. The stimulus of the next trial will be either the same, or of longer or shorter duration in accordance with the Up-Down-Transform Rule (UDTR).
Alternatively, the trial is comprised of stimulating one of two probe units 10 and the patient has to indicate which probe unit 10 was activated.
The TSL method is described in the article by Navarro et al. "Evaluation of Thermal and Pain Sensitivity in Type I Diabetic Patients", Journal of Neurology, Neurosurgery, and Psychiatry 1991, Vol 54, pgs. 60-64, which article is incorporated herein by reference. In the TSL method, the probe is set to the adaptation temperature and the temperature increased at a steady rate until the patient indicates, through patient interface unit 48, that heat sensation or heat pain was felt. The temperature is then decreased until cold or cold pain is felt. The difference between the reversal points (e.g. points where the patient indicated a change in sensation or pain), over a number of trials, is called the TSL.
The staircase method is described in the article by Fowler et al which article is incorporated herein by reference. The probe unit 10 is brought to a predefined temperature level and the patient indicates, via patient interface unit 48, whether or not the stimulus was perceived. The temperature of the probe unit 10 is then brought to a second temperature level which is higher than the first temperature level if the patient indicated that no stimulus was perceived and lower than the first temperature level otherwise. The response of the patient is recorded after each trial. In this manner, an approximate threshold level is determined and is used to determine the range of temperatures to be provided during the second stage of the test.
In the second stage of the test, the temperature of the probe unit 10 is originally brought to a temperature above the level of the approximate threshold level. The patient is then provided with a series of dynamic thermal ramps to bring the temperature to a predetermined level. If the patient indicates that a stimulus was perceived, the next predetermined temperature level is reduced by one predetermined step level. If the patient indicates that no stimulus was perceived, the predetermined temperature level is increased, typically by a predefined step amount. The test terminates when a predetermined number of negative responses have been received. The patient threshold level is defined as the temperature level midway between the mean temperature of the positive responses and the mean temperature of the negative responses.
The suprathreshold method is described in the article by Price D.D., "Measurement of Pain: Sensory Discriminative Features", Psychological and Neural Mechanisms of Pain, Raven Press. NY, 1988, pp. 18-49. In the suprathreshold method, the extent of pain is measured. The temperature of the probe unit 10 is brought from the adaptation temperature to a level above the known threshold for pain (either hot or cold) for a predetermined length of time and then returned to the adaptation temperature. The patient is then asked to describe the intensity of the pain felt, where the intensity can be described by words, by a digital scale, typically varying between 0 and 10 where 0 represents no pain and 10 represents the maximal possible pain, or by a visual analog scale displayed on the screen of laptop computer 28.
In accordance with the present invention, the tests can be performed manually in which the operator have to indicate to laptop computer 28 to start a new trial, or automatically, in which the computer 28 begins a new trial after passage of a length of time set by the operator.
In accordance with the present invention, the results of a test can be compared to those for a normal population in accordance with the age of the patient. Results of tests with normal subjects, "normal data", can be stored in computer 28 in age blocks. If desired, the normal data can be that provided by the manufacturer or it may be data gathered by the operator during his own experiments.
The computer 28 is typically also operative to provide post-processing on the test data. This post-processing typically comprises mathematical analysis of the test data as is required by the testing method, graphical operations for graphically providing to the operator the results of the tests, comparing the results of the test to an age-normalized group or to previous results received for the patient in previous tests.
The apparatus of the present invention enables an operator to choose the appropriate threshold for sensation or pain to be measured, the appropriate location on the body of the patient to place the probe, and the appropriate protocol by which to measure it. Laptop computer 28 stores information regarding each patient as well as the results of each test performed. Furthermore, laptop computer 28 can present the results graphically and can compare them to age-matched normal values for the selected location on the body.
In accordance with the present invention, an operator can modify or define a desired test sequence by programming laptop computer 28 to provide any desired sequence of stimulus intensities and time intervals. The programmable parameters are typically adaptation temperature, sensation or pain to be measured, rate of temperature change, number of trials per test, length of time between trials, manual or automatic triggering of the start of a next trial or test, and providing sound at the start of a test. The order of trials can be randomized and the operator can choose to have trials during which no stimulation occurs. Such trials are known as "catch trials".
Furthermore, the computer 28 enables the operator to define a "default" test or series of tests which is the test or tests which will be run when a novice or non-operator is operating the apparatus of the present invention.
Annex A is source code of software running on laptop computer 28 for operating the apparatus of the present invention in the manner described hereinabove.
Annex B is a collection of typical screen displays preferably provided by the software of Annex A.
Annex C is a collection of typical instruction sets shown to the operator in connection with the screen displays of Annex B relating to programming a new type of test sequence.
It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention is defined only by the claims that follow: ##SPC1##
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Apparatus for measuring threshold sensitivity to a stimulus is disclosed. The apparatus includes sensory stimulation application apparatus for providing stimulus to a subject, computer apparatus for governing operation of the sensory stimulation application apparatus and operator interface apparatus for interfacing between an operator and the computer apparatus. The computer apparatus and the operator interface apparatus include apparatus for enabling an operator to selectably apply sensory stimulation to a patient minimally in accordance with any of the following protocols; method of limits, forced choice method; and staircase method. Other protocols which can be selected are Thermal Sensitivity Limen method and method of suprathreshold.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a regular application of U.S. Provisional Patent Application Ser. No. 60/893,881 filed Mar. 8, 2007 and entitled “HIGH VOLUME, LOW BACK-PRESSURE GAS SCRUBBER”, the entirety of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The field of present invention relates generally to gas scrubbing equipment and, more particularly, to equipment suitable for scrubbing impurities from high volume gas streams without creating a significant rise or increase in back pressure.
BACKGROUND OF THE INVENTION
[0003] Gas scrubbers are used in many industrial processes and applications to clean, remove or “scrub” certain undesirable gaseous components from gas streams in general. One area in which a large number of developments have been made is in the scrubbing of gases produced during, or related to, oil and gas recovery and storage operations. Examples of operations where a gas scrubber is typically used include loading and transportation of sour liquids, venting storage tanks during completion operations and well testing, purging of vessels and pipelines, bleeding off wellheads, venting settling tanks for underbalanced drilling, controlling emissions and odors from industrial processing, controlling vacuum truck emissions and odor control during plant turn-around and tank cleaning operations.
[0004] During such operations, poisonous hydrogen sulfide (H 2 S) present presents a health hazard to workmen in the area. To protect the workmen and the public-at-large, the permissible conditions and levels for emissions of hydrogen sulfide are regulated by various regulatory agencies.
[0005] Conventional systems for the absorption or removal of unwanted contaminants from a gas source or stream often employ a liquid solvent or scavenger to “scavenge” out the H 2 S. An example of such a treatment liquid is the hydrogen sulfide scavengers HSW705 and HSW700 manufactured by Baker Petrolite of Sugar Land, Tex., U.S.A. Information supplied by Baker Petrolite notes that the HSW705 formulation is specifically designed to remove hydrogen sulfide from produced gas and that this liquid product combines with hydrogen sulfide (H 2 S) to form stable, water-soluble reaction products that may be easily removed from the system. Baker Petrolite recommends that the point of injection of the scavenging chemical be as early as conveniently possible in the producing system to maximize contact time, i.e. injection downhole or before wellhead chokes are generally the best points of application. However, this may be impractical in some of the operations noted above, such as during the loading and transportation of sour liquids, venting storage tanks during completion operations and well testing, purging of vessels and pipelines, venting settling tanks for underbalanced drilling, controlling emissions and odors from industrial processing, controlling vacuum truck emissions and odor control during plant turn-around and tank cleaning operations.
[0006] Likewise, Am-Gas Scrubbing Systems (1989) Ltd. of Didsbury, Alberta, Canada distributes and markets chemical products under the trademark PARATENE, which are used as hydrogen sulfide scavengers for use in oilfield and industrial applications and, depending on the exact formulation, forms either water-soluble or oil-soluable by-products. Examples include PARATENE M310, PARATENE M311, PARATENE M315, PARATENE M316, PARATENE M320 and PARATENE M330.
[0007] The prior art is replete with various examples of devices and methods for the “scrubbing” of gas streams using such treatment liquids or liquid scavengers. However, none of the prior art devices provide a relatively portable device which is capable of efficiently removing gases like hydrogen sulfide quickly from large volumes of influent gas and without creating a significant amount of back-pressure. Furthermore, prior art devices have problems with liquid scavenger chemical exiting out of the devices when back-pressures are low, problems with dealing with the high gas volumes and flow rates when they are hooked up to a vacuum truck and problems with providing sufficient contact time to allow the liquid scavenger to treat the gas and remove or “scrub” the hydrogen sulfide. The present invention addresses these problems.
SUMMARY OF THE INVENTION
[0008] In one aspect of the invention there is provided a gas scrubbing system for removing contaminants from a flow of fluid, comprising: a container having an interior volume, an inlet for receiving the flow of fluid and an outlet for dispensing the stream of fluid, a treatment liquid, a contact cell positioned in the interior volume, between the inlet and outlet, for providing a high surface area to facilitate chemical interactions between the fluid flow and the treatment liquid and means to apply the treatment liquid onto the contact cell.
[0009] In another aspect of the invention there is provided a contact cell for use in a gas scrubbing system, comprising a layer of poly-propylene beads.
[0010] In a method aspect, a method to purify a stream of gas is provided. The method comprises the steps of providing a treatment liquid, treating the stream of gas with a first separator to remove any liquid and solid contaminants, scrubbing the stream of gas with a liquid scavenger and treating the scrubbed stream of gas with a second separator to remove any remaining liquid scavenger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a top view of one embodiment of the gas scrubber according to the present invention;
[0012] FIG. 2 is a diagrammatic front sectional view of the gas scrubber of the embodiment of FIG. 1 ;
[0013] FIG. 3 a is a diagrammatic side sectional view of a preferred embodiment of a contact cell;
[0014] FIG. 3 b is a diagrammatic side sectional view of a second embodiment of a contact cell;
[0015] FIGS. 4-5 are front perspective views of the gas scrubber of the embodiment of FIG. 1 ;
[0016] FIGS. 6-9 are top perspective view the gas scrubber of the embodiment of FIG. 1 , looking down into the interior volume of the scrubber;
[0017] FIG. 10 is a front view of a second embodiment of the gas scrubber;
[0018] FIG. 11 is a top view of the gas scrubber of the embodiment of FIG. 10 ; and
[0019] FIGS. 12 a - 12 c are cut-out perspective and top views of another embodiment of the gas scrubber.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] The following description are of preferred embodiments by way of example only and without limitation to the combination of features necessary for carrying the invention into effect. Reference is to be had to the Figures in which identical reference numbers identify similar components. The drawing figures are not necessarily to scale and certain features are shown in somewhat schematic form in the interest of clarity and conciseness.
[0021] Referring to the Figures generally, one embodiment of a gas scrubbing system constructed in accordance with the present invention 10 is illustrated in FIGS. 1-9 , a second embodiment of a gas scrubbing system constructed in accordance with the present invention is illustrated in FIGS. 10-11 and a third embodiment of a gas scrubbing system constructed in accordance with the present invention is illustrated in FIGS. 12 a - 12 c . The three embodiments are similar to each other, differing only in minor aspects as shown in the figures and as further described below. Operation of the three embodiments is also similar, again with the difference between them as shown in the figures and as further described below.
[0022] Referring to the Figures generally, the scrubber system 10 comprises a main vessel or container 12 . The vessel 12 has an interior volume 12 v , an inlet 12 i for receiving a predetermined mass flow rate of gas, that may be contaminated by a pollutant such as hydrogen sulfide, and an outlet 12 o for dispensing the gas once it has been treated with a treatment liquid, scrubber solution or scavenger 22 , 24 . The flow of the gas is from the inlet 12 i to the outlet 12 o and is shown generally by the arrows designated as 15 . Preferably the treatment liquid 22 , 24 is one of the hydrogen sulfide scavengers distributed by Am-Gas Scrubbing Systems (1989) Ltd. of Didsbury, Alberta, Canada under the PARATENE trademark.
[0023] A preferred material for the vessel 12 is steel. In this embodiment, the vessel 12 is conveniently in the form of a hollow box having a closed bottom 12 b and vertical side walls 12 w and measuring approximately 44 inches long by 29 inches wide and 67 inches high. Preferably the system 10 further comprises an open top 16 and a detachable or removable lid 18 . Alternatively, the system 10 may take any other suitable form, such as that of a drum, without departing from the spirit or scope of this invention. Preferably the vessel 12 is a pressure vessel capable of tolerating gas pressures of 1.5 pounds per square inch (psi) or higher.
[0024] The system 10 further comprises at least one suitable conventional spray nozzle 20 to convert a source of liquid scavenger 22 into a spray of droplets 24 . The spray nozzle 20 is provided or mounted to the vessel 12 so as to inject or introduce the liquid scavenger 24 into the upper portion of the vessel's interior volume 12 v . Preferably a plurality of nozzles 20 are provided at various positions inside the vessel's interior 12 v . The embodiment of FIGS. 1-9 has two nozzles 20 depending from the lid 18 (see FIG. 2 ) and three nozzles 20 positioned as shown in FIG. 8 . The embodiment of FIGS. 10-11 has three nozzles depending from the lid. The embodiment of FIGS. 12 a - 12 c , like that of the first embodiment, has as two nozzles 20 depending from the lid (not shown) and three nozzles 20 positioned as shown in FIG. 12 a.
[0025] More preferably, pumping means, in this embodiment comprising a pump 26 along with associated hosing and tubing 28 , are provided to link the source of liquid scavenger 22 to the nozzles 20 in a conventional manner. Even more preferably, the pump is capable of pumping at least 10 gallons per minute so as to ensure that the porous medium 30 remains substantially wetted with liquid scavenger 22 during operations.
[0026] Yet even more preferably, the lower portion of the vessel's interior volume 12 v functions as a retaining reservoir for the source of liquid scavenger 22 . Advantageously, the liquid scavenger 24 released from the nozzle 20 , or nozzles 20 , in the upper portion of the vessel's interior volume 12 v descends to the lower portion and once again become part of the source 22 .
[0027] The system 10 further comprises a high surface area, porous substrate or medium 30 which is placed inside the vessel 12 and in the path of the flow of the gas 15 as it moves from the inlet 12 i to the outlet 12 o . The porous medium 30 minimizes disruption of the normal flow pattern of the flow of gas 15 through the system 10 while at the same time providing a high surface area to carry treatment liquid 22 , 24 that coats the medium, thereby allowing the system 10 to treat high volume gas streams without creating a significant rise or increase in back pressure.
[0028] In this embodiment, the porous medium 30 is in the form of a 6-inch deep bed of approximately ⅛ th inch diameter poly-propylene beads 32 , measuring approximately 44 inches by 22 inches for a total volume of approximately 5808 cubic inches of ⅛th inch poly-propylene beads. Such poly-propylene beads 32 are distributed by Ashland Canada Corp of Richmond, B.C., Canada. The porous medium 30 is located within the interior volume 12 v so as to be substantially “wetted” or coated by the droplets of scavenger 24 exiting the nozzles 20 while at the same time be in the path of all, or substantially all, of the flow of the gas 15 as it moves from the inlet 12 i to the outlet 12 o . Advantageously, this substantially “wetted” high surface area medium 30 provide for numerous interaction sites for treatment liquid 22 to interact with the gas flow 15 . More advantageously, the continual circulation of treatment liquid 22 (by the pump 26 ) from the source, through the nozzle 20 , or nozzles 20 , across the porous medium 30 and back to the source results in an efficient use of said treatment liquid 22 .
[0029] The inventor has observed that using a porous medium 30 with a thickness range of about 6 inches to 30 inches of beads 32 resulted in good scrubbing or treating performance by the system 10 , allowing the system 10 to treat high volumes and flow rate gas streams 15 without creating a significant rise or increase in back pressure.
[0030] Preferably, the porous medium 30 is in the form of a contact cell 30 c and of such dimensions so as to be in the path of most or all of the flow of gas 15 . More preferably the dimensions of the contact cell's periphery are such that a very close tolerance fit is obtained when the contact cell 30 c is placed inside the vessel, thereby providing little room or space for gas to flow around the cell 30 c.
[0031] More preferably the contact cell 30 c further comprises two ½ inch thicknesses of ⅛ inch thick reticulated open-cell foam layers 33 placed directly below and an top of the porous medium (see FIG. 3 a ). Such reticulated open-cell foam layers 33 is distributed by Norwesco Industries (1983) Ltd. of Calgary, Alberta, Canada. Even more preferably, the contact cell 30 c is removable by surrounding or encasing the 6-inch bed of beads 32 , and the open-cell foam 33 , with a 1/16th inch screen material 30 m at the top and bottom and enclosing the sides 30 s with ⅛ th inch steel (see FIG. 3 a ). Advantageously, the thicknesses of open-cell foam 33 provides additional stability and cushioning to the contact cell 30 c as a whole and keeps the beads 32 well packed. More advantageously, the relatively thin layers of foam 33 (only ½ inch total thickness at both top and bottom) acts as a filter material, preventing dirt and debris from lodging in the beads 32 , while allowing the flow of gas 15 through without significantly increasing the back pressures.
[0032] Even more preferably, sealing means (not shown) are used to seal the periphery of the contact cell 30 c against the interior walls of the vessel 12 , thereby ensuring that all of the flow of gas is directed through the contact cell 30 c . The inventor initially utilized a Ethylene Propylene Diene Monomer (EPDM) seal for this purpose. This worked well initially. However, after some time this seal underwent some shrinkage and needed to be replaced. It is speculated that this shrinkage was due to heat. Subsequent experimentation with a buna seal showed that this type of seal did not undergo this kind of shrinkage and therefore lasts longer. It is to be understood that a seal or sealing means is not critical to the invention.
[0033] Advantageously, the contact cell 30 c provides for easy containment of the beads 32 , thereby allowing them to be easily removed, cleaned, replaced and/or serviced when dirty. More advantageously, the contact cell 30 c prevents shifting of the beads 32 during operations on unleveled ground or during transportation of the system 10 .
[0034] The inventor estimates that providing the above-noted 6-inch deep bed of approximately ⅛ th inch diameter poly-propylene beads 32 , measuring approximately 44 inches by 22 inches and having a cross sectional area of 968 square inches and total volume of 5808 cubic inches, results in a surface area of approximately 81,312 square inches plus-or-minus 25%. The inventor observed that using the above-noted contact cell 30 c configuration, with the layers of open-cell foam 33 , and said cell 30 c being substantially wetted with treatment liquid 22 , 24 during gas scrubbing operations, resulted in back pressure of only approximately 18″ water column with a flow rate of approximately 800 standard cubic feet per minute across said bed.
[0035] Another embodiment of a contact cell 30 c (see FIG. 3 b ) comprises two ½ inch thicknesses of mist eliminators or demister pads 34 instead of reticulated open-cell foam 33 , but is otherwise similar to the embodiment of FIG. 3 a . Such demister pads 34 are distributed by Industrial Process Products Ltd. of Calgary, Alberta, Canada. Advantageously, the use of demister pads 34 provides for even less back pressures during operations than a similar thickness of reticulated open-cell foam. The inventor observed that using a substantially wetted (with treatment liquid 22 ) contact cell 30 c configuration of 10½-inch deep bed of approximately ⅛ th inch diameter poly-propylene beads 32 , measuring approximately 44 inches by 22 inches and having a cross sectional area of 968 square inches, but with the two layers of ½ inch thick demister pad 34 (instead of the layers of open-cell foam 33 ), during gas scrubbing operations resulted in very similar back pressures, again of only approximately 18″ water column with a flow rate of approximately 800 standard cubic feet per minute across said bed. However, by using a 10½-inch deep bed of beads 32 , the total surface area provided increased significantly (estimated by the inventor to be approximately 142,296 square inches, plus-or-minus 25%).
[0036] During operations, the inventor observed that, when using this second embodiment of contact cell 30 c (i.e. having demister pad material instead of open-cell foam) in the system 10 of the embodiment shown in FIGS. 12 a - 12 c , the system 10 , using approximately 410 liters of PARATENE M320 treatment liquid 24 , was able to completely scrub a 1½ percent sour (H 2 S) flow of gas 15 (i.e. resulting in 0 ppm H 2 S concentration at the outlet) having a flow rate of 800 cubic feet per minute and only created a back pressure of approximately 18″ water column.
[0037] As will be appreciated by those skilled in the art, a number of factors will determine how long a particular batch of treatment liquid 24 will last before said batch 24 becomes spent and the system 10 , during operation, will start showing signs of H 2 S breakthrough at the outlet 12 o , such as H 2 S concentrations in the range of 5-25 ppm at the outlet. One factor is the particular treatment liquid used. Another factor is the amount of treatment liquid used (for example, one would expect a 200 liter batch of treatment liquid to last roughly half as long as a 400 liter batch, assuming all other factors are equal). A third factor is the H 2 S concentration in the flow of gas 15 . A forth factor is the volumetric flow rate of gas 15 through the system.
[0038] Observations:
[0039] When using 410 liters of PARATENE M320 treatment liquid 24 in the system 10 of the embodiment shown in FIGS. 12 a - 12 c with the second embodiment of the contact cell 30 c ( FIG. 3 b ) and a gas flow 15 rate of 1400 standard cubic feet per minute (SCFM), the inventor has observed the following:
[0040] (i) light duty operation, of scrubbing a gas flow with 2,000 ppm H 2 S concentration at the inlet 12 i , resulted in the system 10 being able to operate for 50 hours or more before any signs of H 2 S breakthrough at the outlet 12 o ; and
[0041] (ii) heavy duty operation, of venting two storage tanks at approximately 80,000 ppm H 2 S concentration at the inlet 12 i , resulted in the system 10 initially having a 20 ppm H 2 S concentration at the outlet 12 o , with this having increased to 80 ppm H 2 S concentration after one hour of operations.
[0042] When the treatment liquid 24 starts showing signs of breakthrough, i.e. it becoming less effective at combining with hydrogen sulfide (H 2 S) to form stable end products and resulting in an unacceptable concentration of H 2 S at the outlet (such as an H 2 S concentration greater than 10 ppm), the liquid scavenger 24 can be drained from the system 10 and replaced with a fresh batch of such treatment liquid 24 .
[0043] Using a contact cell 30 c composed only of demister pad material 34 (see FIGS. 6-7 ) proved to be cost prohibitive in that a given thickness of demister pad is much more expensive that a given thickness of poly-propylene beads 32 and the surface/contact area provided by demister pads is significantly inferior to the amount of surface area provided by a similar thickness of poly-propylene beads 32 .
[0044] Similarly, the inventor has observed that using glass particles, instead of poly-propylene beads also had disadvantages. Although glass particles provide a similar amount of surface area per unit volume, as compared to the poly-propylene bead, one of the disadvantage of such glass particles is that over time they could break into even smaller pieces which may escape from the contact cell and can get caught in the pump 26 , potentially damaging the pump's internal mechanisms.
[0045] Preferably, the scrubber system 10 further comprises an inlet separator 40 and catch reservoir 41 associated with the vessel's inlet 12 i and an outlet separator 42 associated with the vessel's outlet 12 o . More preferably, the inlet and outlet separators 40 , 42 are cyclone separators (see FIG. 2 ). Cyclone separators as such are well-known in the art and rely on generated centrifugal and shear forces to achieve separation into two streams of different densities.
[0046] Briefly and as shown in FIG. 2 , the cyclone separators 40 , 42 comprises a chamber 40 c , 42 c having a vertical axis with an upper cylindrical portion 40 u , 42 u and a lower, inverted frustro-conical portion 40 f , 42 f . The mixture is introduced through a tangential inlet 12 i , 42 i to the cyclone separator, which causes heavier particles to be flung, under centrifugal force, against the outer wall of the chamber and flow downwardly along, as underflow, and around the wall to a lower axial outlet 401 , 421 , while the lighter, remaining, proportion of the mixture is drawn off by an axial pipe, known as a vortex finder 40 v , 42 v , from a point within the body of the cyclone separator 40 , 42 as overflow and conveyed overhead through upper axial outlet 40 u , 42 u . One form of cyclone separator is disclosed in U.S. Pat. No. 4,737,271, but other forms of cyclone separators are known in the art and may also be used. The cyclone separators are preferably used, for the reason that a cyclone separator is a simple, reliable and relatively inexpensive piece of equipment that is highly effective in separating lower and higher density materials.
[0047] Other forms of inlet and outlet separators 40 , 42 may be utilized. For example, FIGS. 12 a - 12 c illustrate another embodiment of the system 10 wherein the separators 40 , 42 comprise a generally cylindrical chamber 40 c , 42 c having a vertical axis, an upper axial outlet 40 u , 42 u and an internal cylindrical member 40 m , 42 m positioned around the upper axial outlet 40 u , 42 and depending partway downward into the separator 40 , 42 . The cylindrical member 40 m has a bottom axial opening 40 b , 42 b . The mixture is introduced into the separator 40 , 42 through one or more a tangential inlets 12 i , 42 i , which, under gravitational and centrifugal forces, causes heavier particles to be flung against the outer wall of the separator and flow downwardly to the bottom of the separator 40 , 42 , while the lighter, remaining, gaseous mixture is forced around the cylindrical member 40 m in a generally downward rotary motion until conveyed into the cylindrical member 40 m (through its bottom axial opening 40 b , 42 b ) and finally out through upper axial outlet 40 u , 42 u.
[0048] Advantageously, the inlet separator 40 facilitates the removal of contaminants 41 c such as oil, water and dirt from the inlet flow of fluid prior to entering the interior volume 12 v (through passage 70 ) and directing said contaminants 41 c into the catch reservoir 41 , thereby preventing such contaminants 41 c from plugging or contaminating the contact cell 30 c . More advantageously, the outlet separator 42 facilitates separation of any liquid scavenger 24 from the gaseous flow 15 (coming via inlets 42 i ), that did not fall back into the source 22 , prior to the gaseous flow exiting of the vessel 12 through the outlet 12 o . Even more advantageously, the axial outlet 42 l directs any separated out scavenger 24 back to the main source 22 , preferably via openings 65 . Alternatively, other forms of separators may be utilized.
[0049] As noted above, the contact cell 30 c provides a high surface area for the liquid scavenger 22 , 24 to cling to, and/or coat, while still allowing for the gas flow 15 to move therethrough without producing a great deal of back pressure. The contact cell 30 c , along with the liquid scavenger 22 , 24 , thereby creates a gas filtering means that results in an efficient absorption of the contaminants (such as hydrogen sulfide) by the scavenger 22 , 24 without creating a large amount of back pressure compared to that in conventional absorption towers or columns (where gas is typically allowed to bubble through a volume of liquid scavenger).
[0050] Preferably, the gas scrubbing system 10 further comprises one or more valved drains 50 , 52 to allow an operator to drain away any contaminants 41 c from the inlet separator 40 and/or liquid scavenger 24 from the system 10 . In this embodiment, drain 50 is associated with the inlet separator 40 to facilitate draining of any contaminants 41 c and drain 52 is associated with the scavenger 24 reservoir to facilitate draining of said scavenger 24 . Even more preferably, the scrubber system 10 further comprises a burst plate 60 associated with the inlet 12 i , so as to protect the vessel 12 and/or any vacuum pump (not shown) that may be hooked up to the system 10 from damage due to excess pressures. Preferably the burst plate 60 is set to burst at 5 psi.
[0051] Those of ordinary skill in the art will appreciate that various modifications to the invention as described herein will be possible without falling outside the scope of the invention.
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In one aspect of the invention there is provided a gas scrubbing system for removing contaminants from a flow of fluid, comprising a container having an interior volume, an inlet for receiving the flow of fluid and an outlet for dispensing the stream of fluid, a treatment liquid, a porous medium positioned in the interior volume, between the inlet and outlet, said porous medium providing a high surface area to facilitate chemical interactions between the fluid flow and the treatment liquid and means to apply the treatment liquid onto the porous medium. A contact cell aspect of the porous medium and a method aspect are also provided.
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BACKGROUND OF THE INVENTION
This invention relates to a liquid fuel gasification device for a liquid fuel combustion apparatus in which liquid fuel is sprayed in an atomized or mist form into an elevated temperature air flow under high pressure and increased whereby the fuel can be efficiently and perfectly gasified.
Liquid fuels such as petroleum-origin fuels have been burnt in various systems and the fuel combustion systems are now generally classified into the pressure-spray, vaporization and gasification systems. These fuel combustion systems have their inherent advantages and disadvantages. The pressure-spray system presents the problem relating to noise and the vaporization system presents the problem relating to slowness in response speed. The third or gasification method also has the following disadvantages because the system has been heretofore based on the conception that the fuel is simply gasified by means of heating wires or the like and these disadvantages are:
1. It takes a rather long time to remove the gas.
2. The combustion of fuel is frequently interrupted because both liquid and gas coexist in the gasification device.
3. The service life of the compenents of the gasification device is relatively short because the fraction having a high boiling point remains in the gasification device.
4. Consumption of electric energy is substantial because the fuel is gasified by electric heating.
SUMMARY OF THE INVENTION
Therefore, the principal object of the present invention is to provide a liquid fuel gasification device whereby liquid fuel is perfectly gasified under quiet combustion or simplified control conditions which are advantages inherent in gas combustion.
In the operation of a liquid gasification device of the invention, liquid fuel is pumped from a fuel supply source through fuel heating means to a spray nozzle by a fluid pump while combustion air is forcibly passed from the atmosphere through air heating means into a mixing or gasification zone. Thus, the liquid fuel is passed through the fuel heating means maintained at a predetermined pressure. The purpose of heating the liquid fuel is to more effectively gasify the fuel which has been sprayed through a spray nozzle and the purpose of pressurizing the fuel is to atomize the fuel into substantially fine particles at the time when the fuel is sprayed through the nozzle and also is based on the finding that the fuel will not boil easily under any pressure, that is, although the higher the temperature of fuel is in the heating means, the more effective the gasification of fuel is, if it is not allowed to raise the temperature of the fuel to its boiling point within the heating means. The reason is that if the fuel is gasified in the heating means, the sprayed amount of the fuel through the spray nozzle is substantially reduced and the passage between the heating means and spray nozzle is liable to be clogged with the fraction of high molecular weight. Thus, even when the fuel is heated under a high pressure condition, the fuel will be seldom gasified to its boiling point as occurs when the fuel is heated to a high temperature under atmospheric pressure conditions. The thus heated and pressurized liquid fuel is then fed to the spray nozzle from which the fuel is sprayed in a fine particle or atomized form into the atmosphere. Since the fuel sprayed in the fine particle form is at an elevated temperature, the size of the fuel particles is substantially finer than that of fuel particles when the same fuel is sprayed at normal temperature and since the pressure of the individual fuel particles is instantly reduced to the atmospheric pressure when the fuel is sprayed, a substantial portion of the sprayed fuel is instantly gasified. However, the instant gasification of fuel presents problems, i.e., one of the problems is that when the fuel particles are gasified, the particles will be deprived of heat of vaporization. If the liquid fuel has imparted thereto an amount of heat sufficient to increase the fuel temperature to its boiling point and a heat amount sufficient to compensate for the lost heat of vaporization, while the fuel is within fuel pressurizing and heating means, there may be no difficulty, but in fact, in order to obtain conditions under which the fuel is heated without causing to gasify up to its boiling point within the pressurizing and heating means, it requires a substantial amount of pressure and is impractical. In such a case, an important impediment is that the boiling point varies within a wide range depending upon the type of fuel employed. In other words, liquid fuels employed in combustion apparatus are generally obtained by fractionating petroleum and refining the fraction, but the boiling point of the fraction varies depending upon the type of fuel and even one type of fuel has a widely varying boiling point range. When considered from the view point of components, the petroleum fuel is a hydrocarbon compound having lower and higher molecular weight components co-existing therein and in general, the higher molecular weight components have higher boiling points. Thus, it can be said that lower molecular weight components will boil easily while higher molecular weight components will hardly boil. If the heating means is designed to heat the liquid fuel under conditions suitable for higher molecular weight components in the fuel, the lower molecular weight components in the fuel would boil in the heating means and as a consequence, the heating conditions in the heating means are necessarily determined based on the properties of the lower molecular components.
Also to take differential pressure, when the amount of heat lost by heat of vaporization is taken into consideration, it is apparent that higher molecular weight components will not be perfectly gasified.
In order to compensate for the deficiency of the amount of heat, a heating means for heating combustion air is employed. More particularly, as to the temperature of air in the atmosphere, there also exists the phenomenon that as the air temperature is increased, saturated vapor pressure changes and the phenomenon is also applicable to liquid fuel. In short, there exists the natural phenomenon that the total amount of liquid fuel allowable to be present in air at room temperature is substantially greater than that of liquid fuel allowable to be present in air at an elevated temperature.
On one hand, when sprayed by a spray nozzle, it may be assumed that the liquid fuel will take the three different phases, that is, gaseous phase, phase just prior to gaseous phase and mist phase. In any one of these phases, the liquid phase is released in a fine particle form into the air. In other words, it means that the surface area of the liquid fuel is increased to a maximum extent and as a consequence, upon contacting an elevated temperature dry air, the liquid fuel is instantly gasified and thus, the gasification of the liquid fuel can be effected in a brief time.
Next, practical methods for carrying out this process will be described hereinbelow:
In carrying out this process, parameters such as amount of heat and pressure required to heat amounts of liquid fuel, and air to be consumed have to be previously set. These parameters vary depending upon the type of liquid fuel. However, for example, it may be assumed that the amount of necessary heat is the amount of heat obtainable from combustion; heat amount for heating air; heat amount for heating fuel are in the relationship of 100: 10: 1. However, in practice, it is necessary that these parameters be elastically determined by taking into consideration the properties of the liquid fuel employed.
Next, the practical methods for carrying out the process will be considered. In order to increase the pressure of liquid fuel, any conventional hydraulic pump can be conveniently employed and there is no difficulty in pressurizing the fuel. On the other hand, the heating of liquid fuel can be effected by any one of the following methods;
I. Heating of fuel:
1. The outer surface of a heating means is surrounded by nichrome wires.
2. Nichrome wires are provided on the inner surface or more particularly, the liquid oil receiving portion of a heating means.
3. A portion of the heat obtained from an air heating means is utilized for heating the liquid fuel.
II. Heating of air:
1. Nichrome wire heating means are provided within an air conduit down stream of a blower to heat air as the air passes by the heating means.
2. A heat accumulating material is heated by nichrome wire heating means of relatively small capacity. In the initiation of operation with a gasification device, the heat accumulated in the heat accumulating material is temporarily utilized until proper operation conditions are obtained whereupon the heat from combustion is utilized.
3. A small capacity pre-combustion means is provided within a air conduit on the downstream of a blower and the heat obtained from the pre-combustion means is employed for heating air.
The above mentioned methods are only illustrative and other methods can be also employed without departing from the spirit of the present invention. It is also within the scope of the invention to heat only air without heating liquid fuel. However, needless to say in the last-mentioned case, it takes a rather long time to perfectly gasify the liquid fuel.
Let us consider applications of the thus perfectly burnt product. The combustion product finds its applications in such combustion devices such as grills, ovens and boilers and internal combustion engines. When the gasification device of the invention is employed in combination with a combustion appliance, although liquid fuel is employed, the gasification operation with the gasification device can be quietly performed under control in the same manner as in a gasification device in which gaseous fuel is employed. The gasification device of the invention can serve a plurality of appliances by connecting the device to the appliance through an insulated piping system. When the gasification device of the invention is employed as a carburetor, since the gasification device can provide a gaseous body having greater surface area than that of the liquid in the form of a mist which is charged into the combustion chamber of a combustion device by a conventional liquid fuel gasification device, the gaseous body can mix with air satisfactorily resulting in perfect combustion. Therefore, the gasification device of the invention has advantages such as saving in fuel, reduction in carbon monoxide contained in exhaust gas and an increase of output. The air to be employed in the gasification device of the invention is combustion air. Therefore, the present invention has advantages that any external air supply source can be eliminated, since air and fuel have been previously mixed together before they are discharged into a combustion chamber, a small excess amount of air is sufficient and since any external air source is unnecessary, combustion with concentrated and intensified heating can be obtained.
The above and other objects and attendant advantages of the present invention will be more readily apparent to those skilled in the art from a reading of the following detailed description in conjunction with the accompanying drawings which show preferred embodiments of the invention for illustrative purpose only but not for limiting the scope of the same in any way.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view of a first or fundamental embodiment of liquid fuel gasification device constructed in accordance with the present invention in which atomized liquid fuel is gasified by high temperature combustion air;
FIG. 2 is a longitudinally sectional view of a second embodiment of liquid fuel gasification device constructed in accordance with the present invention in which liquid fuel is atomized at an elevated temperature under pressure and the atomized fuel is then mixed with pre-heated combustion air whereby the fuel is perfectly gasified by the high temperature air;
FIG. 3 is a longitudinally sectional view of a third embodiment of fuel gasification device constructed in accordance with the present invention in which combustion air is heated by the heat obtained from the combustion of fuel in a pre-combustion means and the heated air is mixed with pre-heated liquid fuel to perfectly gasify the fuel; and FIG. 4 is a longitudinally sectional view of a modification of the embodiment as shown in FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention will be now described referring to the accompanying drawing and more particularly, to FIG. 1 which shows a first embodiment of fuel gasification device of the invention. As shown in the figure, the fuel gasification device generally comprises a main body 1 in the form of a horizontally extending hollow cylinder which is divided into an air supply and heating zone 2, a fuel intake and spray zone 3 in communication at the right hand end (as seen in FIG. 1) with the air supply and heating zone 2, and a mixing zone 4 in communication at the right hand end (as seen in FIG. 1) with the fuel intake and spray zone 3. A blower 5 is provided at the right hand end of the air supply and heating zone 2 within the gasification device main body 1 for forcibly feeding combustion air from the air supply and heating zone 2 through the fuel intake and spray zone 3. Also provided within the air supply and heating zone 2 is a heater 6 which is suitably connected to any suitable conventional electric source (not shown) to be energized thereby and comprises nichrome wire heating elements. The heater 6 is adapted to heat the air from the blower 5 as the air passes through the air supply and heating zone 2 so as to elevate the temperature of the air to a value sufficient to burn liquid fuel discharged into the mixing zone 4. A fuel supply conduit 7 extends from any suitable conventional fuel supply source (not shown) positioned outside of the gasification device into the fuel intake and spray zone 3 and a hydraulic pump 8 is provided in the fuel conduit 7 for pumping the fuel from the fuel source into a spray nozzle 9 supported on a hollow cylindrical nozzle holder 10 which is turn supported at the lower end of the fuel conduit 7 and in fluid communication with the spray nozzle and fuel conduit. The spray nozzle 9 opens into the mixing zone 4 in the gasification device main body 1.
In operation, when the pump is actuated, fuel is pumped from the fuel source through the fuel conduit 7 into the nozzle holder 10 under pressure by the action of the pump 8 and the thus pump fuel is then sprayed through the nozzle 9 in an atomized form into the mixing zone 4.
Simultaneously, the blower 5 is actuated to forcibly pass combustion air through the air supply and heating zone 2 and the heater 6, which has been actuated, at the same time as the pump 8 and blower 5 have been actuated heats the air passing through the zone 2 to a temperature sufficient to burn the fuel. The thus heated air then passes through the fuel intake and spray zone 3 into the mixing zone 4 in which the elevated temperature air rapidly combines with and gasifies the atomized fuel issuing from the spray nozzle 9. The combined vaporized fuel and air mixture passes through the mixing zone 4 into the combustion zone of an associated combustion apparatus (not shown) in which the mixture is ignited.
Referring now to FIG. 2 which shows a second embodiment of the present fuel gasification device, the gasification device generally comprises a main body 110 in the form of a horizontally extending hollow cylinder and an air supply conduit 111 branched from the main body and extending substantially in parallel to a substantial portion of the main body. The main body 110 is divided into a fuel intake and heating zone 112, a fuel spraying zone 113 in communication at the right hand end (as seen in FIG. 2) in the fuel intake and heating zone 112 and a mixing zone 114. The branched air supply conduit 111 is communicated at one end with the juncture between the spraying zone and mixing zone 113 and 114 respectively and has a blower 115 at the other end. A fuel conduit 116 extends from the right hand end of the fuel intake and heating zone 112 to any suitable conventional fuel supply source (not shown) and a hydraulic pump 117 is provided in the fuel conduit 116 for pumping liquid fuel from the supply source through the conduit 116 into a fuel spray nozzle 118 supported by a hollow cylindrical nozzle holder 119 which is suitably mounted in the fuel intake and heating zone 112 and in fluid communication with the fuel conduit 116 and spray nozzle 118. A heater 120 comprising nichrome wire heating elements is mounted within the holder 119 in a suitably shielded condition. The heater 120 is electrically connected to a suitable electric source S to be energized thereby. An air heat exchanger 121 is provided about the air conduit 111 and comprises a plurality of fins and the heat exchanger 121 is positioned adjacent to a combustion chamber 122 of a combustion apparatus associated with the gasification device to be heated thereby.
In operation, when the hydraulic pump 117 is actuated, liquid fuel is pumped under pressure from the fuel source through the conduit 116 into the spray nozzle 118 from which the fuel is sprayed in an atomized condition. As the fuel passes by the heater 120, the fuel is directly heated to a pre-determined elevated temperature sufficient to be partially gasified by the heater 120 which has been energized simultaneously when the pump 117 has been actuated. Thus, the atomized fuel, immediately after the fuel has been sprayed through the nozzle 118, comprises a perfectly gasified component and the remaining partially gasified component.
Simultaneously, the blower 115 is actuated to forcibly pass combustion air through the air conduit 111 into the mixing zone 114 to mix with the sprayed fuel and as the air passes through the conduit 121, the air is indirectly heated through the conduit by the fins 121 which have been heated with the heat from the combustion chamber 122.
With the construction of the embodiment of FIG. 2, in the initial stage of the operation of the gasification device, the air is not heated, only the perfectly gasified component of the sprayed fuel in other words, only the component of the sprayed fuel which can be contained in the cool air is burned with the combustion air in the combustion chamber 122 and since the interior of the combustion chamber is heated as the combustion progresses, the air is heated by the temperature of the fins which have now been increased as the air passes through the conduit 111 and the heated air perfectly gasifies the sprayed fuel when the air mixes with the fuel in the mixing zone 114 to thereby increase the combustion efficiency of the fuel mixture. With the construction of the embodiment of FIG. 2, since it takes a certain time interval before a sufficiently heated air is obtained, if desired, any means which accelerates the re-gasification of the condensed fuel within the mixing zone 114 can be provided or alternatively, the air may be initially heated by a nichrome wire heater within the scope of the invention.
FIG. 3 shows a third embodiment in which the heat obtained by a pre-combustion means is utilized for heating liquid fuel. The gasification device of FIG. 3 generally comprises a main body 220 in the form of a horizontally extending hollow cylinder which is divided into a liquid fuel intake and heating zone 221, a fuel spraying zone 222 in communication at the right hand end with the fuel intake and heating zone 221 and a mixing zone 223 in communication at the right hand end with the spraying zone 222 and an air conduit 224 extending vertically and upwardly from and in communication with the fuel intake and heating zone 221. A fuel conduit 225 extends from the right hand end of the fuel intake and heating zone 221 to an external suitable fuel supply source (not shown) and a fluid pump 226 is provided in the conduit 225 for pumping liquid fuel under pressure from the supply source into a heat exchanger 227 suitably mounted within the fuel intake and heating zone 221 and having a plurality of fins 227' thereabout. A fuel spray nozzle 228 is provided at the inner end of the heat exchanger 227 for receiving the liquid fuel from the heat exchanger 227 and spraying the fuel in an atomized condition. A blower 229 is provided at the upper end of the vertical air conduit 224 for forcibly passing combustion air through the conduit 224 into the fuel intake and heating zone 221. A pre-combustion means 230 is suitably provided within the air conduit 224 and has a fuel conduit 231 extending from the top of the pre-combustion means 230 to an external fuel supply source (not shown) and an ignition means 232 is positioned adjacent to the nozzle end of the pre-combustion means 230 and electrically connected through a conductor 233 to an external electric source. The fuel to be employed in the pre-combustion means 230 may be combustible gas or kerosene, which has calories as low as one tenth that of gasified liquid but the fuel is preferably selected from those which have a rapid response to obtain satisfactory results.
In operation, when the pump 226 is actuated, the liquid fuel is pumped under pressure from the external supply source through the heat-exchanger 227 into the spray nozzle 228 from which the liquid fuel is sprayed in an atomized condition. Simultaneously, the fan 229 is actuated to forcibly pass the air downwardly into the fuel intake and heating zone 221. The pre-combustion means 230 is also simultaneously actuated to burn the combustible gas or kerosene therein and the combustion product is sprayed at the lower nozzle end thereof.
In operation, the pre-combustion means 230 is actuated to spray the combustible gas or kerosene through the lower end spray nozzle and the ignition means 232 is actuated. Simultaneously, the blower 229 is actuated to forcibly pass air through the air conduit 224 downwardly into the fuel intake and heating zone 221. Thus, the combustion gas or kerosene is ignited at the time when the fuel is sprayed from the pre-combustion means 230 whereby the air is heated. The heated air impinges against the heat exchanger 227 to heat the heat exchanger and the heat permeates through the wall of the heat exchanger. Since the heat exchanger 227 has the plurality of fins 227 thereabout, the heat exchanger has an increased heat transfer area to effect heat transfer to the fuel passing through the heat exchanger more effectively. When the temperature of the heat exchanger has reached a predetermined value, the pump 226 is actuated to pump liquid fuel under pressure from the fuel supply source through the heat exchanger into the spray nozzle 228 from which the fuel is sprayed in an atomized condition into the mixing zone 223 in which the atomized fuel mixes with the heated air from the air conduit 224. Since the heat exchanger has been sufficiently heated, the liquid fuel will have been sufficiently heated before the fuel is sprayed from the spray nozzle 228 and can be perfectly atomized as soon as the fuel is sprayed into the mixing zone. Since the temperature of the fuel will not be increased in excess of that of the heated air, no hazard will occur. It is only necessary to set the heating temperature of the combustion air to a predetermined value to thereby ensure a long service life for the entire gasification device.
The embodiment of FIG. 4 is a modification of the embodiment of FIG. 1 and is substantially similar to that of FIG. 1 except for the disposition of the parts which are similar in function to the corresponding parts of FIG. 1 and are indicated by the same reference numerals as employed in FIG. 1. In FIG. 4, the blower 5 is provided within the downwardly extending extension of a main body 1 and the nichrome wire heating means 6 extends horizontally into the air supply and heating zone 2 above the blower 5. The fuel conduit 7 having the hydraulic pump 8 extends horizontally through the main body proper parallel to and above the heating means 6, into the fuel intake and spray zone 3, and supported in the nozzle holder 10 at the inner end of which the spray nozzle 9 is mounted in fluid communication with the fuel conduit 7. The outer end of the fuel conduit 7 is connected to and in fluid communication with a external fuel supply source (not shown). The mixing zone 4 is in fluid communication at one end with the spraying zone and at the other end in communication with the burner 4 which in turn is in communication with the combustion chamber of an associated combustion apparatus (not shown). The operation of the embodiment of FIG. 4 is identical with that of the embodiment of FIG. 1 and a description of the operation will be omitted herein.
While several embodiments of the invention have been shown and described in detail, it will be understood that the same are for illustration purpose only and not to be taken as a definition of the invention, reference being had for the purpose of the appended claims.
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A perfect fuel gasification device for use in combination with a combustion apparatus in which there is provided a hollow cylindrical main body divided into a plurality of operation zones, an air or fuel conduit extending from and in fluid communication with said main body, fuel intake-spraying or intake-heating-spraying means and air heating means wherein liquid fuel is heated to a temperature below its boiling point under a high pressure, with the heated fuel being introduced into the spray means in a mist form to provide a wide contact surface and the fuel mist being mixed with an elevated temperature air to be perfectly gasified thereby.
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FIELD OF THE DISCLOSURE
[0001] The disclosure relates to surfaces having hydrophobic/oleophobic properties and methods of making them. The surfaces disclosed may be used, for example, in touch screen applications or other applications that involve contact with human skin.
BACKGROUND
[0002] When skin comes in contact with glass, not treated to be smudge resistant it leaves an oily residue that is difficult to remove. By treating the glass, one can increase both the hydrophobicity and oleophobicity of the surface allowing for smudge resistance and easier cleaning of the glass.
[0003] Current methods of treating glass to increase hydrophobicity and oleophobicity of the surface involve treating glass with a perfluoropolyetherfunctional trimethoxysilane that requires the use of an expensive fluorinated solvent. The problems associated with this method center on cost of materials, film quality (i.e. uniformity, robustness, and pin-hole formation) and processability of the film and time of cure.
[0004] There remains a need for an easily applied coating that provides a water contact angle between 100°-120° and an oleic acid contact angle ranging from 70°-90° and that also provides the desired quality and abrasion resistance.
SUMMARY
[0005] The inventors have now developed a surface treatment by which less expensive materials can be used to accomplish the target contact angles and abrasion resistance in less time compared to conventional techniques.
[0006] One embodiment is a method comprising providing a surface comprising surface hydroxyl groups; applying an amine to the surface to form a first coated surface; applying a fluorinated silane compound to the first coated surface to form a second coated surface; and reacting the silane with the amine and surface hydroxyl groups to form a crosslinked network between the amine, fluorinated silane and surface.
[0007] An additional embodiment is an article comprising a substrate and a layer chemically bonded to the substrate comprising a fluorinated silane crosslinked with an amine.
[0008] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.
[0009] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.
[0010] The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and operation of the various embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a graph comparing contact angle measurements for three embodiments.
[0012] FIG. 2 is a graph comparing contact angle measurements as a function of test cycles for two embodiments.
[0013] FIG. 3 is a graph comparing contact angle measurements before and after 85/85 temperature/humidity testing.
DETAILED DESCRIPTION
[0014] A first embodiment is a method comprising providing a surface comprising surface hydroxyl groups; applying an amine to the surface to form a first coated surface; applying a fluorinated silane compound to the first coated surface to form a second coated surface; and reacting the silane with the amine and surface hydroxyl groups to form a crosslinked network between the amine, fluorinated silane and surface.
[0015] In one embodiment, the provided surface is glass. The provided surface may be present as a layer on a substrate, for example, the provided surface may be a glass layer on a substrate. In another embodiment, the provided surface is a glass substrate. In yet another embodiment, the provided surface is a polymer, either alone or as a layer on a substrate.
[0016] The provided surface comprises surface hydroxyl groups. As used herein, the term hydroxyl group refers to the functional group (—OH). In some embodiments, the surface hydroxyl group may be present in the form of a silanol, where the hydroxyl group is bonded to a silicon atom. The number of surface hydroxyl groups on the provided surface may be increased, for example, by plasma cleaning the surface.
[0017] In one embodiment, the amine and the fluorinated silane compound are applied in a two-step process. First, the amine is applied to the provided surface to form a first coated surface, followed by applying the fluorinated silane compound to the first coated surface to form a second coated surface. The amine may be applied to the provided surface using any suitable technique, such as, dip coating or aerosol coating. In one embodiment, dip coating may comprise dipping the surface in an amine for a period of 10 seconds, 1 minute, 2 minutes or more. In one embodiment, the amine alone may be applied to the provided surface. In other embodiments, the amine may be dispersed in a solvent then applied to the provided surface.
[0018] The fluorinated silane compound may be applied to the first coated surface using any suitable technique, such as, dip coating or aerosol coating. In one embodiment, dip coating may comprise dipping the surface in a fluorinated silane compound for a period of 10 seconds, 1 minute, 2 minutes or more. In one embodiment, the fluorinated silane compound alone may be applied to the first coated surface. In other embodiments, the fluorinated silane compound may be dispersed in a solvent then applied to the first coated surface.
[0019] Appropriate solvents include those that are anhydrous, hydrophobic, slow to evaporate and non-reactive with the amine or fluorinated silane compound. Example solvents include aliphatic hydrocarbons such as hexanes, cyclohexane, heptane; substituted aliphatic hydrocarbons such as ethyl lactate; and aromatic hydrocarbons such as toluene.
[0020] In one embodiment, the amine functions as a catalyst, promoting the reaction between the fluorinated silane compound and the surface hydroxyl groups. In another embodiment, the amine functions as a crosslinker to form a network between the silicon of the silane, the nitrogen of the amine and the oxygen of the surface hydroxyl groups. In some embodiments, the amine may function as both a catalyst and a crosslinker.
[0021] In one embodiment, the amine is multifunctional. As used herein, a multifunctional amine is defined as an amine compound having more than one amine group, for example, a diamine or a triamine.
[0022] In one embodiment, the amine comprises a primary or secondary amine, for example, an amine comprising one or two R groups attached to the nitrogen atom. The amine may also comprise at least two primary or at least two secondary amine groups. In one embodiment, the amine is a polyetheramine. Suitable amines include polyetheramines, for example, Jeffamine® Diamines D-230 and D-400; Jeffamine® Triamine T-403; and Jeffamine® EDR-148 and EDR-176. In one embodiment, the amine is selected from tetraethylenetetramine (TETA) and tetraethylenepentamine (TEPA). In one embodiment, the amine is ethylene diamine.
[0023] The fluorinated silane compound may be chosen to tailor the final properties of the treated surface. As used herein the term “fluorinated silane” refers to chlorosilanes containing as least one perfluorinated, or partially fluorinated, aliphatic or aromatic substituent. In one embodiment, the silane is a fluorinated alkyl silane. Suitable silanes include perfluoralkyltrichlorosilanes, for example, perfluorooctyltrichlorosilane, and fluorinated alkylsilanes such as (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trichlorosilane. The solubility of the silane in the solvent can be considered when choosing the most appropriate combinations of silanes and solvents. In this respect, the solubility of the silane in standard hydrocarbon solvents decreases as the degree of fluorination increases.
[0024] The reactions involving the silane with the amine and hydroxyl groups may occur spontaneously. In one embodiment, the reaction may be driven to completion via heating, for example, in an oven. The treated surface may be heated for example at 100 degrees C. for 10 minutes, 20 minutes, or more. Heating may also be employed to evaporate any excess solvent remaining on the surface.
[0025] Some embodiments include a drying step between and/or after amine and/or silane applications. Depending on the solvent, the first coated surface may be air dried for a period of time, such as 1 minute, 5 minutes, 10 minutes or more before the fluorinated silane compound is applied. Furthermore, the second coated surface may be air dried for a period of time, such as 1 minute, 5 minutes, 10 minutes or more before heating.
[0026] In one embodiment, the crosslinked network formed between the amine, fluorinated silane and surface includes silicon of at least a portion of the silane bonded to the nitrogen of at least a portion of the amine and at least a portion of oxygen of the surface hydroxyl groups. In one embodiment, the crosslinked network forms a hydrophobic coating on the provided surface. Hydrophobic surfaces include those surfaces that are antagonistic to water, mostly incapable of dissolving in water in an appreciable amount or being repelled from water or not being wetted by water.
[0027] In one embodiment, the crosslinked network forms an oleophobic coating on the provided surface. Oleophobic surfaces include those surfaces that lack an affinity to oils.
[0028] A second embodiment is an article comprising a substrate; and a layer chemically bonded to the substrate comprising a fluorinated silane crosslinked with an amine.
[0029] In one embodiment, the substrate is glass. In another embodiment, the substrate is a polymer.
[0030] In one embodiment, the layer comprising a fluorinated silane crosslinked with an amine includes silicon of the silane bonded to nitrogen of the amine. The layer is chemically bonded to the substrate via bonds between the silicon of the silane and oxygen of the surface hydroxyl groups.
[0031] In one embodiment, the layer is a hydrophobic surface, for example, the surface has a water contact angle greater than 95 degrees, such as, greater than 98 degrees, greater than 100 degrees, or greater than 105 degrees. In one embodiment, the surface is oleophobic, for example, the surface has an oleic acid contact angle greater than 70 degrees.
[0032] Various embodiments will be further clarified by the following examples.
[0033] Glass substrates were cleaned in an ultrasonic bath containing a 4% soap solution. After ultrasonic cleaning, the glass substrates were rinsed twice in DI water to remove any soap residue. The glass substrates were placed in a plasma cleaner and air plasma cleaned for 10 minutes to remove any residual organic material from the surface and form silanol groups on the surface.
[0034] Two separate solutions were prepared for coating the glass substrates. First, an amine solution comprising 0.15 ml of ethylene diamine (EDA) suspended in 150 ml of hexanes. Second, a fluorinated silane compound solution comprising 0.2 ml of (Heptadecafluoro-1,1,2,2-tetrahydrodecyl)trichlorosilane (HDFTCS) in 150 ml of hexanes.
[0035] The air plasma treated glass substrates were first placed into the amine/hexanes solution for 1 minute. After 1 minute, the glass substrates were removed and allowed to air dry. Once visibly dry the amine coated glass substrates were placed in the silane/hexanes solution for 1 minute. After 1 minute, the substrates were air dried, placed in a holder, and placed in a 100° C. oven for one hour. After the one hour post bake, the substrates were rinsed with water followed by a rinse with ethanol and blown dry with a stream of nitrogen.
[0036] Three glass substrates were prepared using the method described above. Sample A was not treated with an amine catalyst/crosslinker prior to silane coating. Sample B was treated with EDA prior to silane coating and Sample C was treated with triamine functional polyetheramine (TA) prior to silane coating. All three samples were treated with HDFTCS.
[0037] Contact angle measurements for water (represented as squares) and oleic acid (represented as circles) are shown for the three samples in FIG. 1 .
[0038] The results of an abrasion resistance test of samples B and C are shown in FIG. 2 , which graphs the contact angle as a function of test cycles. A test cycle is defined as a forward and reverse wipe of the sample surface; the contact angle is measured at various points throughout the process up to 10,000 test cycles. Water contact angle for sample B is represented as a solid square and oleic acid contact angle for sample B is represented as an open square. Water contact angle for sample C is represented as a solid triangle and oleic acid contact angle for sample C is represented as an open triangle.
[0039] Additional glass samples were prepared as above using trifunctional polyetheramine in toluene (2 minutes) and fluorosilane in hexanes (1 minute). Samples were collected from each step of the process and tested in 85/85 temperature/humidity conditions for 672 hours. Samples were as follows: 1) control, 2) ethanol rinse step between amine and silane dips, 3) ethanol rinse step after silane dip, 4) ethanol rinse after amine and silane steps, 5) 15 min bake at 100° C. after amine step, and 6) ethanol rinse and 15 min bake at 100° C. after amine step. FIG. 3 compares the contact angle measurements for water before, represented by open squares, and after testing, represented by solid triangles. Also shown in FIG. 3 are contact angle measurements for oil before, represented by solid circles, and after testing, represented by open triangles.
[0040] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.
[0041] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the invention. Since modifications combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and their equivalents.
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Surfaces having hydrophobic/oleophobic properties and methods of making them. The surfaces disclosed may be used, for example, in touch screen applications or other applications that involve contact with human skin.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority from provisional application No. 60/286,908, filed Apr. 27, 2001. The present application is a continuation-in-part of application Ser. No. 10/135,875 filed on Apr. 29, 2002, which is hereby incorporated by reference in its entirety.
BACKGROUND
[0002] Image sensors receive light into an array of photosensitive pixels. Each pixel may be formed of a number of cooperating elements including, for example, a lens, often called a “microlens”, a color filter which blocks all but one color from reaching the photosensitive portion, and the photosensitive portion itself. These elements are typically formed on different physical levels of a substrate.
[0003] It has typically been considered that the elements of the pixels should have their centers substantially exactly aligned. That is, the microlens, the color filter, and the photosensitive portion should each be substantially coaxial. The physical process used to create the semiconductor will have inherent errors, however, conventional wisdom attempts to minimize these errors.
SUMMARY
[0004] The present application teaches a way to improve image acquisition through intentional shift among different optical parts of the optical elements in the array. This may be done to compensate for various characteristics related to acquisition of the image.
[0005] In an embodiment, the amount of shift may be variable throughout the array, to compensate for imaging lens angles. That is, the amount of shift at one location in the array may be different than the amount of shift at other locations in the array. Such a variable relative shift may also be used to obtain a three-dimensional view.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] These and other aspects will now be described in detail with reference to the accompanying drawings, wherein:
[0007] FIG. 1 shows a layout of optical parts including microlens and color filter array which is aligned directly with its underlying photosensitive part;
[0008] FIG. 2 shows a layout of optical parts with a shift among the centers of the microlens/filter array and the photosensitive part;
[0009] FIG. 3 shows the effect of varying angles of incidence with shifts among microlens and image sensor;
[0010] FIG. 4 shows an improved technique where shifts among optical part and photosensitive part are configured to maintain the light incident to the proper photosensitive element;
[0011] FIG. 5 shows an exemplary light graph for a number of different angles of incidences;
[0012] FIGS. 6A and 6B show a graph of output vs. angle of incidence for a number of different angles of incidences; and
[0013] FIG. 7 is a block diagram of a processor based system incorporating the image sensor of FIG. 4 in accordance with an exemplary embodiment of the invention.
DETAILED DESCRIPTION
[0014] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those of ordinary skill in the art to make and use the invention, and it is to be understood that structural, logical or procedural changes may be made to the specific embodiments disclosed without departing from the spirit and scope of the present invention.
[0015] The present application teaches a photosensor with associated parts, including passive imaging parts, such as a lens and/or color filter, and photosensitive parts. An alignment among the imaging parts and the photosensitive parts is described.
[0016] The imaging parts may include at least one of a microlens and/or a filter from a color filter array. The photosensitive parts may include any photosensitive element, such as a photodiode, photogate, or other photosensitive part.
[0017] FIG. 1 shows a typical array used in an image sensor that is arranged into pixels, such as a CMOS image sensor array. The image sensor array 100 is divided into a number of different pixel areas 102 , 104 . Each different pixel area may include a photosensor 106 therein, for example a photodiode or the like. The photosensor 106 is preferably a CMOS type photosensor such as the type described in U.S. Pat. No. 5,471,515. Each pixel such as pixel 102 also appends a color filter 110 in a specified color. The color filters 110 collectively form a color filter array. Each pixel may also append an associated microlens 120 . In FIG. 1 , the center axis 125 of the microlens 120 substantially aligns with the center axis 115 of the color filter 110 which also substantially aligns with the center axis 105 of the CMOS photosensor 106 .
[0018] FIG. 2 shows an alternative embodiment in which the centers of the elements are shifted relative to one another. In the FIG. 2 embodiment, the center line 225 of the lens 220 may be substantially aligned with the center line 215 of the color filter 210 . However, this center line 215 / 225 may be offset by an amount 200 from the line 205 of the photosensor 201 which represents the point of maximum photosensitivity of the photosensor 201 . Line 205 may be the center of the photosensor 201 . That is, the filters 210 and microlenses 220 have shifted centers relative to the line 205 of the photoreceptor/photosensor 201 . According to an embodiment, the amount of shift is controlled to effect the way the light is received into the photosensitive part of the pixels.
[0019] The shift among the pixels may be configured to minimize the crosstalk among neighboring pixels. This crosstalk may be spatial crosstalk among the neighboring pixels and spectral crosstalk within the pixel. In addition, the shift may be used to compensate for irregular beam angles during imaging, for example due to non telecentric imaging.
[0020] Relative shift among the microlenses and filter, and the photosensitive pixel centers, can vary across the array. According to an embodiment, the variable shift among the microlens/filter and pixel can be modeled according to the following equation:
S = D tan { sin - 1 [ sin ( θ ) n ] } = D tan { sin - 1 [ sin ( Mr R ) n ] }
[0021] Where S is the variable shift among the center of the microlens and/or filters and the center of peak photosensitivity or minimum crosstalk region of the pixel, shown as 200 in FIG. 2 . This center line, shown as 205 in FIG. 2 , may be variable as a function of beam entry angles. D represents the physical distance between the plane of the microlens/filters and the plane of the peak photosensitive region of the pixels. The variable θ represents the external beam entry angle, and n is the refractive index of the medium between the microlens/filter and the photosensitive region of the pixel.
[0022] The beam entry angle θ can be replaced by the quotient Mr/R for general calculations, where M is the maximum beam angle of non-telecentricity, i.e. the maximum beam entry angle given at the maximum image point radius. The variable r is the image point radius under consideration for calculating S. R is the maximum image point radius.
[0023] When the alignment among the optical elements is nonzero (S≠0), the misalignment may cause crosstalk among neighboring pixels, and may cause beams to arrive from irregular angles in the image plane. This may be especially problematic when non telecentric lenses are used for imaging. FIG. 3 shows how light at different angles of incidences will strike the pixel bases at different locations. Beams which are incident at angles <0, such as beam 300 , strike the base of the pixel near, but not at, the pixel's peak photosensitive region. That is, the beam remains in the pixel, but misses the specific “sweet spot” of maximum photosensitivity.
[0024] The beams which are incident at angles equal to zero, such as beam 305 , hit exactly on the pixel's “sweet spot” that is the area of maximum photosensitivity. Beams which are incident at other angles, such as beam 310 , may, however, strike the base of the neighboring pixel. This forms spatial crosstalk.
[0025] FIG. 4 shows the specific layout, with shifted pixel parts, which is used according to the present system. Each of the beams 400 , 405 , 410 are shifted by the lens and filter array such that each of the pixel photoreceptors hits a position of maximum photosensitivity of the CMOS image sensor.
[0026] To observe or test the performance of relative pixel shift as a function of beam incidence angle, numerous arrays can be fabricated with a single unique relative shift among the lens/filter and pixel center. A single array can also be used with deterministically varying relative shifts among the microlenses and pixels across the array. The array is illuminated at various angles of incidences and the response and crosstalk of the array is recorded. A single array may be fabricated with deterministically varying relative shift among the microlenses and pixel elements. The pixel may then be viewed three-dimensionally, at different angles of incidences. This may be used to test the performance of the trial and error determination.
[0027] FIG. 5 shows a number of captured images. These images were captured using a CMOS image sensor whose microlenses and filters were offset in the varying amount across the arrays similar to the technique shown in FIG. 4 . That is, the microlens/filter is aligned over the center of its respective pixel in the center of the array, then the microlens/filter is gradually shifted off of its respective pixel's center moving toward the edge of the array until at the very edge of the array the microlens/filter was centered over the very edge of its respective pixel. In this manner, illumination of the whole array produced a (whole-array) picture of a single pixel's spatial photosensitivity map for any given angle of incidence and color. Illumination in these images was quasi plane wave white light and incident at angles specified in each of the elements. The center of FIG. 5 shows a pixel's spatial photosensitivity map under an angle of incidence of θ x =0, θ y 32 0. This output may be used to white balance the sensor output for optimal relative shift position. The other parts of the figure show the response of the sensor for different angles of incidence of the illuminating light.
[0028] FIG. 6A shows a graph which tracks the RGB values of pixel located at x=320, y=283 (“pixel 320, 283”) under various horizontal angles of illumination, while FIG. 6B plots the RGB values of pixel 320, 283 under various vertical angles of illumination. Note that the RGB values under normal incidence have been white balanced for that pixel to a value of 196 (and that 196 is not the maximum value this pixel experiences under various angles of illumination). These plots show how the color and sensitivity vary under various angles of illumination for a given relative shift among the microlens/filter and the physical center of the pixel.
[0029] In this experiment, the apparent motion of a given pixel's white balance may be tracked as the illumination angle of incidence is varied. This may be compared to a variable shift among the microlenses and pixels. An optimum variable shift to compensate for given angles of incidence can be deterministically obtained.
[0030] For example, the sensor, whose images are shown in FIG. 5 may benefit from a variable shift among the microlens, filters and pixels of 8 nm per pixel, if the imaging lens used with this sensor array suffers from a non-telecentricity of +/−30 degrees at the edges of its image field. This can be seen from the images in FIG. 5 which shows that the apparent motion is one pixel across −30 to +30 degrees. That represents 640 pixels horizontally for which there is a variable microlens shift of 8 nm per pixel. This enables calculating the total microlens shift of 5.12 microns. The corresponding variable shift microlens placement correction factor, for non telecentric imaging should therefore be 0.085 microns per degree.
[0031] Thus, for any image, there exists an additional one degree of non telecentricity. The relative shift among the microlens centers and pixel centers should hence be reduced towards the center of the array by 85 nm.
[0032] For example, if the 85 nm per degree variable shift is substituted into equation 1, that is S=85 nm when θ equals one degree, and we assume a relative dielectric refractive index n=1.5, then the depth (i.e., D) from the plane of the microlens to the plane of the specified feature comes out D=7.3 microns. This result is very close to the value from the plane of the microlens layer to the plane of the metal one (M 1 ) layer in the array under examination as estimated from the fabrication design rules (7.2 microns +/−0.2 microns).
[0033] The microlenses according to this system may be spherical, cylindrical, or reflowed square footprint lenses. Use of microlenses with deterministic prismatic properties may be employed if non-telecentric imaging optics are used.
[0034] An aspect of this system includes minimizing the crosstalk from the resulting received information. Crosstalk in the image sensor may degrade the spatial resolution, reduce overall sensitivity, reduce color separation, and lead to additional noise in the image after color correction. Crosstalk in CMOS image sensors may generally be grouped as spectral crosstalk, spatial optical crosstalk, and electrical crosstalk.
[0035] Spectral crosstalk occurs when the color filters are imperfect. This may pass some amount of unwanted light of other colors through the specific filter.
[0036] Spatial optical crosstalk occurs because the color filters are located a finite distance from the pixel surface. Light which impinges at angles other than orthogonal may pass through the filter. This light may be partially absorbed by the adjacent pixel rather than the pixel directly below the filter. The lens' optical characteristics, e.g. its F number or telecentricity, may cause the portion of the light absorbed by the neighboring pixel to vary significantly. Microlenses located atop the color filters may reduce this complement of crosstalk.
[0037] Electrical crosstalk results from the photocarriers which are generated from the image sensor moving to neighboring charge accumulation sites. Electrical crosstalk occurs in all image sensors including monochrome image sensor. The quantity of crosstalk in carriers depends on the pixel structure, collection areas size and intensity distribution.
[0038] Each of these kinds of crosstalk can be graphed, and the optimum shift for the crosstalk reduction can be selected. For example, each of the spectral crosstalk, optical crosstalk and electrical crosstalk can be separately viewed. The different types of crosstalk can then be separately optimized.
[0039] FIG. 7 shows system 2000 , a typical processor based system modified to include an image sensor as depicted in FIG. 4 as part of an imager device 2040 . Processor based systems exemplify systems of digital circuits that could include an image sensor. Examples of processor based systems include, without limitation, computer systems, camera systems, scanners, machine vision systems, vehicle navigation systems, video telephones, surveillance systems, auto focus systems, star tracker systems, motion detection systems, image stabilization systems, and data compression systems for high-definition television, any of which could utilize the invention.
[0040] System 2000 includes central processing unit (CPU) 2010 that communicates with various devices over bus 2070 . Some of the devices connected to bus 2070 provide communication into and out of system 2000 , illustratively including input/output (I/O) device 2050 and imager device 2040 . Other devices connected to bus 2070 provide memory, illustratively including random access memory (RAM) 2060 , and one or more peripheral memory devices such as floppy disk drive 2020 and compact disk (CD) drive 2030 .
[0041] Other embodiments are within the disclosed invention. While the invention has been described in detail in connection with preferred embodiments known at the time, it should be readily understood that the invention is not limited to the disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. For example, the offset may be calculated without the refractive index n. Accordingly, the invention is not limited by the foregoing description or drawings, but is only limited by the scope of the appended claims.
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An image sensor is formed with shifts among the optical parts of the sensor and the photosensitive parts of the sensor. The optical parts of the sensor may include a color filter array and/or microlenses. The photosensitive part may include any photoreceptors such as a CMOS image sensor. The shifts allow images to be formed even when the light received at a given pixel location varies in angle of incidence as a function of pixel location within the array. The relative shifts among the pixel components may be, for example, plus or minus some fraction of the pixel pitch. The shift may be variable across the array or may be constant across the array and may be deterministically determined.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001]
[0000]
D129880
August 1941
Hafner
D350613
September 1994
Fahy, Jr.
D419783
February 2000
Tavenas
D438381
March 2001
Sijmons
1281385
October 1918
Johnson
6581736
June 2003
Scicluna
1608924
November 1926
Brown
1696245
December 1928
Manley
2010/0205737
August 2010
Peterson
2011/0000017
January 2011
Peterson
2011/0023232
February 2011
Sun
D454430
March 2002
Sijmons
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX
[0003] Not Applicable
BACKGROUND OF THE INVENTION
[0004] In accordance with an embodiment of the present Invention relates to a modified suitcase incorporating a compartment from which would extend a lightweight telescopic cot. There is a suitcase with a built in collapsible cot structure in the back comprising a fabric Web, a frame, and folding legs. When set up, the cot structure provides for a person to lie down or sit on top of the fabric. There is a divider, where divider separates the luggage first compartment and cot in second compartment in one particular embodiment. The lugcot modification would ensure a place to set or sleep, was always available and the traveler did not have to rest upon the floor or ground. Not only will present invention benefit traveler, it will benefit camper for backpacks, military backpacks, forest fire fighter's backpacks.
[0005] The present suitcases only provide the service of carrying clothing and cosmetics. This Invention would carry clothing, cosmetics and bed.
BRIEF SUMMARY OF THE INVENTION
[0006] The Invention a modified suitcase would incorporate a compartment from which would extend a lightweight Cot. The design of his article of luggage would ensure the individual luggage was always attended as the cot would be secured to the base of the luggage. Thus, it would eliminate the luggage from being stolen. In this sense, this invention would provide travelers with enhanced safety and peace of mind.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0007] FIG. 1 Back of luggage
[0008] FIG. 2 Side of luggage
[0009] FIG. 3 Angle of Luggage
[0010] FIG. 4 LUGCOT wheels and material not shown
DETAILED DESCRIPTION OF THE INVENTION
[0011] The present invention relates to a travel luggage with a telescopic Cot extendable therefrom. The present invention provides travel Luggage that includes two compartments. One compartment is provided for the placement of clothing, toiletries and other travel accessories and a second compartment is provided where a telescopic Cot is stored. The present invention allows for the extension of a Telescopic Cot from the back of the Luggage. This Luggage along with Cot provides a means for a Traveler to create a bed to relax during an extended lay-over at an airport, or on a hiking or camping trip, when visiting relatives, for military backpacks when wrist is needed and for forest fire fighters.
[0012] In reference to FIG. 1A , a perspective view of a Travel Luggage 6 views is depicted. The travel luggage includes a Main Body 3 , with a First Side 2 . As shown in FIG. 1 , the back view Side 1 , the back angle view 4 , opens and allows the extension of a Cot 5 , for use by the owner. The Cot 5 , extends from a Compartment 1 , as shown in FIG. 1 of the Luggage 4 . In addition to the First first 1 , the Luggage 1 also includes a Second Compartment also shown in FIG. 1 . When in a closed position the Luggage 1 is similar to any other respective travel luggage that is used on the market. Travel Luggage 1 according to the present invention includes two compartments, one for storing clothing and other travel accessories in Second Compartment 7 and the First Compartment 6 for the storage of an Cot.
[0013] In reference to FIG. 1B , a perspective view of a Travel Luggage, 8 views is depicted, 1Locking Pin and Cot and frame of Cot. FIG. 1B a Perspective view shows the Cot being set up in a matter of minutes.
[0014] In reference to FIG. 1C a perspective view of a Travel Luggage, view 8 , Locking Pin.
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The present suitcases only provide the service of carrying clothing and cosmetics. This Invention would carry clothing, cosmetics and bed.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 11/946,454 (now U.S. Pat. No. 8,641,724), filed Nov. 28, 2007, which is a continuation of PCT/US2006/024858, filed on Jun. 26, 2006, which claims priority from U.S. Application No. 60/696,319, filed on Jun. 30, 2005, the full disclosures of each which are incorporated herein by reference.
BACKGROUND
Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the present invention relates to devices and methods for creating or modifying a fistula between a first vessel and a second vessel, such as for the treatment of chronic obstructive pulmonary disease.
Chronic obstructive pulmonary disease affects millions of patients in the United States alone. The present standard of care is externally supplied oxygen therapy, which requires a patient to remain near a stationary oxygen source or carry a bulky oxygen source when away from home or a treatment facility. It is easy to appreciate that such oxygen therapy has many disadvantages.
Lung reduction surgery has recently been proposed for treating patients with chronic pulmonary disease. Such surgery, however, is not a panacea. It can be used on only a small percentage of the total patient population, requires long recovery times, and does not always provide a clear patient benefit. Even when successful, patients often continue to require supplemental oxygen therapy.
There is therefore a need for improved approaches, including both devices and methods, for treating patients suffering from chronic obstructive pulmonary disease. If would be desirable if such devices and methods were also useful for treating patients with other conditions, such as congestive heart failure, hypertension, lung fibrosis, adult respiratory distress syndrome, and the like. Such devices and methods should provide for effective therapy, preferably eliminating the need for supplemental oxygen therapy in the treatment of chronic obstructive pulmonary disease. There is a need for simplified devices and procedural methods that reduce costs to the patient and healthcare system, as well as decrease procedure times and minimize patient risks. Improved devices and procedures must be developed to apply to a broad base of patient populations with a wide range of applicable arteriovenous anatomies. At least some of these objectives will be met by the invention described hereinafter.
BRIEF SUMMARY OF THE INVENTION
According to a first aspect of the invention, a device for creating a fistula in a patient is disclosed. The device comprises an elongate tubular structure comprising a proximal end and a distal end. The distal end is configured to penetrate or otherwise pass first through the skin of the patient, then through a first vessel, and then into a second vessel. The device includes an integral assembly configured to create a fistula between two neighboring vessels. In a preferred embodiment, the first vessel is an artery and the second vessel is a vein. In an alternative, also preferred embodiment, the first vessel is a vein and the second vessel is an artery. The fistula is typically created at a location wherein the artery and vein vessel walls are within 20 mm of each other. The fistula is created to provide therapeutic benefit, such as for an acute period less than twenty-four hours, a sub-chronic period between twenty-four hours and thirty days, or for a chronic period greater than thirty days. The fistula creation assembly is preferably mounted on a core that is slidable within an outer sheath of the device. The fistula creation assembly can be uncovered from the sheath by an operator through advancement of the core, retraction of the sheath, or a combination of the two movements. In a preferred embodiment, a second slidable core, such as a slidable needle assembly with a sharpened, beveled tip, is slidingly received by the first core. When fully advanced, the needle assembly exits the distal end of both the sheath and the first core, and assists in penetrating first through the skin of the patient and then through the tissue that exists along the trajectory to the proposed fistula. Both the first core and the sheath preferably have tapered ends to assist in penetration and/or advancement through the skin and tissue up to the fistula site. In another preferred embodiment, the needle assembly includes a guidewire lumen for insertion of a guidewire from outside the patient's body, through the first vessel and into the lumen of the second vessel. In another embodiment, the needle assembly is removable. In a preferred embodiment, the device is rigid along a majority of its length. In an alternative embodiment, the device is flexible along a majority of its length, such as a flexible section that can be advanced down a segment of the first vessel prior to entering the second vessel. In another alternative embodiment, the device includes both flexible segments and rigid segments along its length.
The fistula creation assembly of the present invention can be configured in numerous forms to produce the desired fistula. In a preferred embodiment, a cone shaped dilator is expanded and/or delivers energy to create the fistula. In another embodiment, an expandable balloon is used to create the fistula. An anastomotic implant is preferably deployed to initially create the fistula and/or to improve the long-term patency of the fistula. The implant can perform numerous functions, and may include self-expanding materials, plastically deformable materials, or a combination of self-expanding or plastically deformable materials. In a preferred embodiment, the anastomotic implant forms the fistula into an oval cross section. In an alternative embodiment, the anastomotic implant forms the fistula into a circular cross section. Numerous forms of energy can be used to create and/or improve the fistula, including energies selected from the group consisting of: electrical energy such as radiofrequency or microwave energy; cryogenic energy; heat; radiation; chemical energy; light such as light delivered to photoreactive agents; and combinations thereof. The fistula creation assembly may deliver an agent to the fistula and its surrounding tissue, such agents selected from the group consisting of: anti-proliferative; anti-biotic; anti-thrombogenic; and combinations thereof.
In a preferred embodiment, the device is configured to create a fistula to treat a patient suffering from COPD, such as via the fistula decreasing systemic vascular resistance of the patient. In these and other patient populations, the fistula may provide therapy by increasing the oxygen content of venous blood, such as blood supplied to a lung of the patient. The fistula may additionally cause oxygen content in arterial blood to also increase. The fistulas of the present invention are configured to have blood flow through the fistula of at least 5 ml/min, and preferably greater than 50 ml/min.
In yet another preferred embodiment, the device includes a handle at its proximal end. The handle includes one or more controls, such as controls to advance and/or retract a slidable core. In a preferred embodiment, one or more controls are included to perform a function selected from the group consisting of: initiate or modify the delivery of energy to an intended or existing fistula location; expand a distal portion of the device such as an expandable dilator or inflatable balloon; deploy an implant such as an anastomotic device which applies tension between the two vessels at the fistula location and/or scaffolds the lumen of the fistula; and combinations thereof.
In yet another preferred embodiment, the device is configured to create a fistula in a limb of a patient, such as between an artery and vein selected from the group consisting of: axillary artery; brachial artery; ulnar artery; radial artery; profundal artery; femoral artery; iliac artery; popliteal artery; carotid artery; saphenous vein; femoral vein; iliac vein; popliteal vein; brachial vein; basilic vein; cephalic vein; medial forearm vein; medial cubital vein; axillary vein; and jugular vein. In an alternative embodiment, the fistula is located in the abdomen or thorax of the patient.
In yet another preferred embodiment, the fistula creation device further comprises a flow measurement element, such as an ultrasound or Doppler ultrasound element, or a lumen that allows a flow measurement catheter to be inserted into the proximal end of the device and advanced to a location near or beyond the device's distal end. Flow measurement can be made directly using Doppler technologies and techniques, or indirectly by measuring flow channel geometries.
In yet another preferred embodiment, the fistula creation device further comprises flow adjustment means mounted to one or more of the outer sheath or an inner core. The flow adjustment means can be activated on demand by an operator and preferably includes: an energy delivery element; an agent delivery element; an inflatable balloon; an expandable dilator; a deployable implant such as a second implant of the fistula creation device; and combinations thereof.
According to a second aspect of the invention, a system for creating a fistula is disclosed. The system includes one or more of the embodiments of the fistula creation device of the first aspect of the invention, and an ultrasound visualization monitor. The visualization monitor may be configured to display information received from one or more ultrasound crystals integral to the fistula creation device, or may work with separate device such as an external or internal ultrasound probe.
According to a third aspect of the invention, a system for creating a fistula is disclosed. The system includes one or more of the embodiments of the fistula creation device of the first aspect of the invention, and an apparatus selected from the group consisting of: a balloon catheter; an anastomotic implant deployment catheter; a flow measurement device such as a flow catheter or an external Doppler probe; an angiography catheter; a venography catheter; a guidewire; an introducer; a needle; a biopsy needle; and combinations thereof. In a preferred embodiment, the system further comprises an ultrasound visualization monitor configured to provide an image received from one or more of: an ultrasound element integral to the fistula creation device; an external ultrasound probe; and an internal ultrasound apparatus such as an intravascular ultrasound catheter; and an inserted probe such as a transesophageal probe.
According to a fourth aspect of the invention, a method of creating a fistula is disclosed. The distal end of a fistula creation device is placed through the skin of the patient. The distal end, which is preferably the distal end of a sharpened, beveled tip needle assembly, such as a removable needle assembly, is advanced through a first vessel, such as a vein or an artery. The distal end is then advanced into a second vessel at an existing-fistula or an intended-fistula location. A fistula is then created, or an existing fistula is maintained, such that a long-term flow of blood is provided between the first vessel and the second vessel. The fistula creation device includes an elongate tubular structure that may be rigid along a majority of its length, may be flexible along a majority of its length, or may include rigid and flexible portions such as two rigid portions attached with a flexible hinge. In a preferred embodiment, blood flows from the first vessel to the second vessel. In an alternative, also preferred embodiment, blood flows from the second vessel to the first vessel. At the intended fistula location of the patient, the vessels may lie in various geometric configurations, such as wherein the first vessel is “on top” of the second vessel such that the lumen of the first vessel lies relatively proximate the shortest line between the lumen of the second vessel at the fistula location and the surface of the patient's skin. In alternative fistula locations, the vessels may lie in a more “side-to-side” configuration. When inserted, the elongate body of the fistula creation device is positioned to lie relatively in the plane defined by the lumens of the two vessels near the intended fistula location. While maintaining position within this plane, the fistula creation device can be inserted at an angle relatively perpendicular to the surface of the patient's skin, or at a smaller angle, such as an angle between 20 and 80 degrees. This insertion angle may be chosen by the clinician to affect the fistula angular geometry between the two vessels, such as at a small insertion angle to correspond to a similarly small angle between the lumen of the first vessel and the lumen of the fistula. Such a small angle between the first vessel lumen and the fistula lumen may be desirous to reduce turbulent flow through the fistula. In alternative embodiments, an insertion angle approximating ninety degrees may be chosen in order to minimize the length of the fistula.
In a preferred embodiment, the method further comprises the step of determining the anatomical location for the fistula. Prior to creating the fistula, the fistula location is determined using one or more of: angiography; venography; extra-vascular ultrasound; intravascular ultrasound; Doppler ultrasound; and MRI. The fistula location is determined based on an analysis of a parameter selected from the group consisting of: first vessel diameter; second vessel diameter; artery diameter; vein diameter; ratio of artery to vein diameter; distance between the artery and vein lumens; geometric relationship between the artery and vein lumens; distance from an arterial side branch; distance from an venous side branch; arterial flow; venous flow; oxygen content in artery; oxygen content in vein; wall thickness of artery; wall thickness of vein; degree of calcification of artery; degree of calcification of vein; geometric relationship between the artery and vein lumens at the fistula site; hemodynamic factors; other parameters; and combinations thereof.
In another preferred embodiment, the method further comprises the step of performing a blood flow measurement procedure, such as a procedure performed prior to fistula creation, during fistula creation, after fistula creation, and combinations thereof. The information determined during the flow measurement procedure can be used to select the fistula site, modify the fistula such as a balloon dilation fistula modification procedure and/or otherwise treat the fistula.
In yet another preferred embodiment, an anastomotic implant is placed in the fistula. The anastomotic implant is placed to provide a function selected from the group consisting of: scaffolding an opening between the first vessel and the second vessel; reducing neointimal proliferation into the fistula flow path; preventing tissue from protruding into the fistula flow path; placing a portion of the first vessel wall in tension with the tissue of the second vessel wall; reducing bleeding of the tissue neighboring the fistula; enhancing healing of the tissue neighboring the fistula; and combinations thereof. The anastomotic implant may include one or more coatings, such as anti-bacterial; anti-thrombogenic and anti-prolific coatings. The anastomotic implant may additionally or alternatively include a covered portion, such as a partial covering, such covering materials selected from the group consisting of: polytetrafluoroethylene; Dacron; Nitinol; stainless steel; and combinations thereof. The fistula creation device of the present invention preferably places the anastomotic implant.
In yet another preferred embodiment, a guidewire is placed between the first and second vessel through the fistula, prior to, during, or after the fistula is created. The guidewire preferably remains in place after the fistula creation device is removed, or partially removed, such that a second catheter device can be placed over that guidewire. The second catheter device can be used to perform a diagnostic event such as a radiographic dye injection catheter inserted to perform angiography or venography, or an ultrasound catheter used to visualize the fistula structure. The second catheter device can be used to modify the fistula such as a balloon catheter inserted to enlarge the fistula or an anastomotic implant deployment catheter inserted to increase or decrease flow through the fistula.
In yet another preferred embodiment, the fistula is created to provide therapeutic benefit that results from: a decrease is systemic vascular resistance; an increase in the oxygen content in at least a portion of the venous system such as the venous supply to a lung of the patient; and combinations thereof. Blood flow through the fistula is at least 5 ml/min and preferably greater than 50 ml/min. The fistula is preferably created between an artery and a vein at a location in a limb of the patient. The artery is selected from the group consisting of: axillary artery; brachial artery; ulnar artery; radial artery; profundal artery; femoral artery; iliac artery; popliteal artery; and carotid artery. The vein is selected from the group consisting of: saphenous; femoral; iliac; popliteal; brachial; basilic; cephalic; medial forearm; medial cubital; axillary; and jugular. The artery is preferably between 5 mm and 25 mm in diameter at the intended fistula location. The vein is preferably less than 35 mm in diameter at the intended fistula location. The fistula preferably has a non-circular or oval cross section, such that the major axis of the oval is greater than either the vein diameter or the artery diameter. In an alternative embodiment, the fistula has a circular cross section. The geometry of the cross section of the fistula is preferably matched with a similar geometry of an anastomotic implant placed during the disclosed method.
According to a fifth aspect of the invention, a kit for creating a long-term fistula in a patient for the treatment of COPD is disclosed. The kit includes a first fistula creation device for forming a fistula with a first geometry. The kit further includes a second fistula creation device for forming a fistula with a second geometry. Either the first or the second fistula creation device is used to create the long-term fistula based on an analysis of information gathered during a visualization procedure performed on the patient. The visualization procedure is preferably selected from the group consisting of: ultrasound visualization including intravascular ultrasound and extravascular ultrasound; angiography; venography; MRI; and combinations thereof. The first fistula creation device and the second fistula creation device can be configured to create a first fistula and a second fistula respectively. The first fistula and the second fistula may have two different cross sectional geometries, such as a circular and an oval cross sections, two different circular cross sections or two different oval cross sections. Varied oval cross sections may include ovals with different major axes and different minor axes, and ovals with different major axes with similar minor axes.
Both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the embodiments of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the present invention, and, together with the description, serve to explain the principles of the invention. In the drawings:
FIG. 1 illustrates a partial cross sectional side view of a fistula creation apparatus consisting with the present invention;
FIG. 2 a illustrates a cross sectional side view of a fistula creation apparatus consistent with the present invention shown with a slidable needle assembly in the advanced position;
FIG. 2 b illustrates the fistula creation apparatus of FIG. 2 a with the needle assembly removed;
FIG. 2 c illustrates the fistula creation apparatus of FIG. 2 b with an outer sheath retracted such that an integral anastomotic implant is partially expanded;
FIG. 2 d illustrates the fistula creation apparatus of FIG. 2 c with the outer sheath further retracted such that the integral anastomotic implant is fully expanded;
FIG. 3 a is a cross sectional side view of a device and method for creating a fistula consistent with the present invention shown prior to advancement of the device through the patient's skin;
FIG. 3 b illustrates the device and method of FIG. 3 a shown with the distal end of a slidable needle assembly of the device having penetrated the skin and the first wall of an artery;
FIG. 3 c illustrates the device and method of FIG. 3 b shown with the needle assembly having further penetrated a second wall of the artery and a first wall of a vein, and a guidewire having been advanced down the vein through a lumen of the needle assembly;
FIG. 3 d illustrates the device and method of FIG. 3 c shown with the needle assembly having been retracted while leaving the guidewire seated in the vein;
FIG. 3 e illustrates the device and method of FIG. 3 d shown with an anastomotic implant of the device partially deployed in the vein;
FIG. 3 f illustrates the device and method of FIG. 3 e shown with the anastomotic implant of the device fully deployed in the fistula between the artery and the vein, and the device outer sheath partially retracted from the patient;
FIG. 4 a is a cross sectional side view of a device and method for creating a fistula consistent with the present invention shown with advancement of the distal end of the device through the patient's skin and into an artery and an ultrasound probe located proximate the entry site;
FIG. 4 b illustrates the ultrasound image produced by the ultrasound probe of FIG. 4 a.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
FIG. 1 depicts a preferred embodiment of the fistula creation device of the present invention. Device 10 is configured to be inserted by an operator through the skin of a patient to create and/or maintain a fistula that provides a flow of blood between a first vessel and a second vessel, such as a long-term flow of blood to achieve a therapeutic benefit. Device 10 includes an elongate tubular structure with a proximal end and a distal end, the tubular structure comprising multiple tubes that surround or are slidingly received within a separate tube. Each tube may have a rigid, semi-rigid, and/or flexible construction and each tube comprises one or more materials such as: nylon; polyvinyl chloride; polyethylene; polypropylene; polyimide; Pebax™; Hytrel™; polyurethane; silicone; steel; Nitinol™; blends, alloys and copolymers of the preceding, or other biocompatible materials, and may include a structural braid such as a nylon or metal braid commonly used in interventional guide catheters. Each tube may include a tapered, sharpened, beveled, expandable such as balloon expandable, and/or energy emitting distal end, and each tube may include one or more lumens, such as a Teflon-lined or Teflon-coated lumen. The elongate tubular structure may be rigid or flexible along a majority of its length, or may include both rigid and flexible portions such as two rigid portions separated by a flexible hinge portion. Device 10 further includes, on its proximal end, handle 40 , which is grasped by an operator to advance, retract, rotate, control, activate, and/or otherwise manipulate device 10 or a component or sub-assembly of device 10 . Each advanceable and/or retractable tube of device 10 may be attached at its proximal end to one or more advancement and/or retraction controls, such as a tube that is operably attached to a control integral to or proximate to handle 40 . Handle 40 may include additional controls, such as a control to enlarge a dilator, inflate a balloon, deploy an implant, initiate energy or agent delivery, activate a diagnostic device and/or perform another function.
The outermost tube, outer sheath 30 , which preferably has a tapered distal end and is constructed of a biocompatible plastic, surrounds and slidingly receives a first slidable core, inner core 20 , which includes conically tapered tip 21 and is preferably constructed of biocompatible metal and/or plastic. Fistula creation assembly 25 is mounted near the distal end of inner core 20 and is configured to create a fistula on demand by an operator. Fistula creation assembly 25 may include one or more of various means to create the fistula such as a cone shaped dilator, not shown, such as a dilator that is expandable and/or configured to deliver energy. Fistula creation assembly 25 may include a force-exerting balloon, such as a compliant or non-compliant balloon and/or a balloon to dilate an implant. Alternatively or additionally, fistula creation assembly 25 may include a delivery assembly and an anastomotic implant, such as a vessel-to-vessel tensioning anastomotic clip and/or a fistula scaffolding assembly. Alternatively or additionally, fistula creation assembly 25 may include an energy delivery element such as an element configured to deliver electrical energy such as radiofrequency or microwave energy; cryogenic energy; heat; radiation; chemical energy; light; and/or other forms of energy. Energy may be delivered to ablate tissue, cut tissue and/or coagulate blood and tissue. Alternatively or additionally, fistula creation assembly 25 may include an agent delivery assembly, such as an agent delivery mechanism configured to deliver one or more of anti-proliferatives; anti-biotics; and anti-thrombogenics. In a preferred embodiment, fistula creation assembly 25 further is configured to modify an existing fistula, such as a fistula created by device 10 previously used to create the fistula, or by a separate device 10 or an alternative fistula creation device, such as during the same medical procedure or a previously performed procedure. In order to modify an existing fistula, fistula creation assembly 25 may include an anastomotic implant, such as a second anastomotic implant nested within a first implant, an expandable balloon, an energy or agent delivery element, a tissue removing element such as a forward or pull back atherectomy catheter, or other means. Other fistula modifying events can be performed such as the placement of an implant, which partially covers the fistula from either the venous or arterial side.
Referring back to FIG. 1 , fistula creation assembly 25 is operably attached to conduit 26 , a flexible or rigid conduit which travels proximally to handle 40 . Conduit 26 may include one or more of: a power or data transfer conduit such as one or more electrical wires and/or optical fibers, a tube such as an inflation lumen or cryogenic flow tube; and a slidable cable such as a pull wire. Conduit 26 is electrically attached through an electrical switch control, button 42 , to another control on handle 40 , port 41 . Port 41 is an electrical jack that can be attached to an energy delivery unit such as an RF generator, not shown. An operator depresses button 42 to deliver energy to fistula creation assembly 25 . In an alternative or additional embodiment, port 41 is attached to a balloon endoflator that is used to inflate a balloon integral to fistula creation assembly 25 . In another alternative or additional embodiment, port 41 is attached to a drug delivery pump or supply to deliver drugs to fistula creation assembly 25 . Outer sheath 30 is operably attached to a control on handle 40 , sheath retraction knob 32 , which can be slid proximally by an operator to retract outer sheath 30 and subsequently slid distally to advance outer sheath 30 . Outer sheath 30 is retracted to expose fistula creation assembly 25 , such as when fistula creation assembly 25 is an expandable balloon and/or an anastomotic implant delivery assembly such as an assembly including a self-expanding anastomotic implant. In an alternative embodiment, inner core 20 is advanced to expose fistula creation assembly 25 , or a combination of advancing inner core 20 and retracting outer sheath 30 is performed. Inner core 20 is operably attached to core advancement knob 22 of handle 40 such that inner core 20 can be advanced and retracted by sliding core advancement knob 22 forward or back.
Located in the distal portion of inner core 20 and in proximity to fistula creation element 25 is visualization element 70 , preferably an ultrasound element such as a phased array of ultrasound crystals, signal and power wires not shown, or a rotating ultrasound crystal, rotating shaft and signal and power wires not shown. Visualization element 70 can be electrically connected to an ultrasound monitor, not shown, such that a cross sectional view of the tissue and other structures surrounding the distal portion of device 10 and fistula creation assembly 25 can be visualized. In alternative embodiments, visualization element 70 consists of a visualization marker, such as an ultrasonically reflective surface that can be visualized with an external ultrasound probe, a radiopaque marker that can be visualized under fluoroscopy, a magnetic marker, and other markers compatible with visualization equipment found in hospitals, doctor's offices and other health care settings. An operator utilizes visualization element 70 during various procedural steps involving device 10 , such as penetration of its distal end through the skin and vessels of the patient and rotational orientation of the device. Visualization element 70 also provides valuable information prior to, during, and after the activation of fistula creation element 25 such as information relating to the inflation of a balloon and/or placement of an anastomotic implant. In an alternative embodiment, device 10 further includes a flow measurement element, not shown, preferably embedded in visualization element 70 , such as a Doppler ultrasound function. In another alternative embodiment, a visualization catheter or flow measurement catheter is inserted in a lumen of device 10 , such as within the lumen of inner core 20 in which needle assembly 50 is inserted, a separate lumen of inner core 20 not shown, or a lumen of outer sheath 30 . In a preferred embodiment, device 10 further includes a visualization and/or flow measurement monitor, such as a Doppler ultrasound monitor.
A second slidable core, needle assembly 50 , is slidingly received within a lumen of inner core 20 . Needle assembly 50 , which may be rigid or flexible along its length, is preferably constructed of one or more metals such as stainless steel and Nitinol. Needle assembly 50 can be retracted, and completely removed from the lumen of inner core 20 by retraction of yet another control of handle 40 , needle retraction knob 52 . In an alternative embodiment, full removal of needle assembly 50 is prevented by the inclusion of one or more mechanical stops. Needle assembly 50 has a sharpened distal tip 51 , which is preferably sharp and beveled. Needle assembly 50 includes a lumen from its proximal end to its distal end, guidewire lumen 53 , which is configured to allow a standard interventional guidewire to be advanced therethrough, and further configured to allow needle assembly 50 to be removed leaving the previously inserted guidewire to reside within the lumen of inner core 20 previously inhabited by needle assembly 50 . In an alternative embodiment, needle tip 51 may be configured to deliver energy, such as RF energy used to assist in advancement, and/or to cauterize, cut and ablate tissue.
In a preferred embodiment, a kit is provided for the creation of multiple fistulas, in a single patient or multiple patients, includes multiple fistula creation devices of FIG. 1 with varied fistula creation elements in each device. An operator selects a specific fistula creation device based on the configuration of the fistula creation element included in that device. In one alternative, a first fistula creation device creates a fistula with a different geometry than a second fistula creation device, such as might be chosen to differentiate a fistula between vessels with a first set of luminal diameters and a second set of fistulas with different luminal diameters. Numerous fistula creation parameters can be varied between a first fistula creation device and a second fistula creation device such as use of energy, fistula diameter, fistula cross section geometry such as circular cross section versus elliptical cross section wherein the major diameter of the ellipse is at least 20 percent larger than the minor diameter of the ellipse. In a preferred embodiment, the major diameter of the fistula is at least twice the minor diameter. In another preferred embodiment, a kit includes a first fistula creation device with a target fistula cross section dimensions having unequal major and minor axes, and a second fistula creation device with a target fistula cross section dimensions have similar minor axis length and greater major axis length. In a preferred method, an operator selects either the first fistula creation device or the second fistula creation device based on a visualization procedure performed on the anatomy of the patient proximate the intended fistula creation site.
Referring now to FIGS. 2 a through 2 d , a preferred embodiment of a fistula creation device of the present invention is shown in various stages of a preferred method of activation. Referring specifically to FIG. 2 a , device 10 is configured to be inserted by an operator through the skin of a patient to create and/or maintain a fistula that provides a flow of blood between a first vessel and a second vessel, such as a long-term flow of blood to achieve a therapeutic benefit. Device 10 includes an elongate tubular structure with a proximal end and a distal end, the tubular structure comprising multiple tubes that surround or are slidingly received within a separate tube. Each tube may have a rigid, semi-rigid, and/or flexible construction and each tube comprises one or more materials such as: nylon; polyvinyl chloride; polyethylene; polypropylene; polyimide; Pebax™; Hytrel™; polyurethane; silicone; steel; Nitinol™; blends, alloys and copolymers of the preceding, or other biocompatible materials, and may include a structural braid such as a nylon or metal braid commonly used in interventional guide catheters.
The outermost tube, outer sheath 30 , which preferably has a tapered distal end, surrounds and slidingly receives a first slidable core, inner core 20 , which includes conically tapered tip 21 . Outer sheath 30 includes on its proximal end sheath advancement knob 32 , which is manipulated by an operator to advance and retract outer sheath 30 . Inner core 20 includes on its proximal end, core advancement knob 22 , which is manipulated by an operator to advance and retract inner core 20 . Balloon 25 is mounted near the distal end of inner core 20 and is expandable on demand by an operator, inflation lumen and endoflator attachment port not shown, such as to create the fistula and/or expand an implant placed to maintain the fistula. Balloon 25 may comprise a compliant or non-compliant balloon. Surrounding balloon 25 is an anastomotic implant, clip 60 , which is deployed in the fistula to perform one or more functions including but not limited to: scaffolding an opening between the first vessel and the second vessel; reducing neointimal proliferation into the fistula flow path; preventing tissue from protruding into the fistula flow path; placing a portion of the first vessel wall in tension with the tissue of the second vessel wall; and reducing bleeding of the tissue neighboring the fistula; enhancing healing of the tissue neighboring the fistula. In a preferred embodiment, the anastomotic implant includes an active agent, such as an anti-thrombogenic or anti-proliferative agent, and may also include a covering or partial covering.
A second slidable core, needle assembly 50 , is slidingly received within a lumen of inner core 20 . Needle assembly 50 , which may be rigid or flexible along its length, is preferably constructed of one or more metals such as stainless steel and Nitinol. Needle assembly 50 can be retracted, and completely removed from the lumen of inner core 20 by retraction of needle retraction knob 52 . In a preferred embodiment, Inner core 20 can also be retracted, and completely removed from the lumen of outer sheath 30 , by retraction of knob 20 . Needle assembly 50 has a sharpened distal tip 51 , which is preferably sharp and beveled. Needle assembly 50 includes a lumen from its proximal end to its distal end, guidewire lumen 53 , which is configured to allow a standard interventional guidewire to be advanced therethrough, and further configured to allow needle assembly 50 to be removed leaving the previously inserted guidewire to reside within the lumen of inner core 20 previously inhabited by needle assembly 50 . In an alternative embodiment, needle assembly 50 is partially retracted but remains within lumen of inner core 20 . In another alternative embodiment, needle tip 51 may be configured to deliver energy, such as RF energy used to assist in advancement, and/or to cauterize, cut and ablate tissue. In a preferred method, device 10 is advanced through the skin, through a first vessel and into the lumen of a second vessel with needle assembly 50 in the fully advanced position. A locking mechanism, not shown, may be engaged to prevent relative motion between needle assembly 50 and outer sheath 30 during insertion and subsequent advancement. A guidewire is then advanced through guidewire lumen 53 and further advanced down the lumen of the second vessel.
Referring now to FIG. 2 b , needle assembly 50 has been completely removed from the lumen of inner core 20 , such as when a guidewire has been successfully placed from a location outside the patient's skin to and into the second vessel. Referring now to FIG. 2 c , the distal end of clip 60 has been released from being constrained by outer sheath 30 , either by retraction of outer sheath 30 , advancement of inner core 20 , or a combination of both movements. Clip 60 of FIGS. 2 a through 2 d is self-expanding, such as a resiliently biased tubular structure made of Nitinol. In FIG. 2 d , clip 60 has been fully released from being constrained and is in a fully expanded condition. Balloon 25 has been inflated, inflation lumen and endoflator attachment not shown, to provide additional expansion force to clip 60 . In an alternative embodiment, clip 60 is plastically deformable, or includes plastically deformable portions, such that balloon 25 is required to expand clip 60 . In a preferred embodiment, device 10 of FIGS. 2 a through 2 d is used as a system in conjunction with one or more additional devices to create and/or maintain the fistula. Such additional devices include but are not limited to guidewires and various over-the-wire devices that are placed over the guidewire placed through needle assembly 50 , after needle assembly 50 is removed. These additional over-the-wire devices may be placed within a lumen of inner core 20 , within a lumen of outer sheath 30 with inner core 20 removed, or over the guidewire after device 10 has been completely removed. These over-the-wire devices include but are not limited to: balloon catheters; anastomotic implant delivery devices and implants; flow measurement catheters; angiography catheters; venography catheters; and other over-the wire devices applicable to modifying the fistula, such as modifying the flow of the fistula, or to perform a procedure to otherwise enhance and/or maintain the long term benefit of the fistula.
Referring now to FIGS. 3 a through 3 f , a preferred method of using the fistula creation device of the present invention is shown. A cross sectional view of a patient's anatomy at a proposed fistula location 111 is depicted wherein artery 130 is directly above vein 120 in relation to skin surface 105 . Intended fistula location 111 may be determined using one or more visualization techniques including but not limited to: angiography; venography; extra-vascular ultrasound; intravascular ultrasound; and MRI. Intended fistula location 111 may be determined using one or more flow measurement techniques such as Doppler ultrasound. The intended fistula location 111 may be selected based on parameters selected from the group consisting of: first vessel diameter; second vessel diameter; artery diameter; vein diameter; ratio of artery to vein diameter; distance between the artery and vein lumens; geometric relationship between the artery and vein lumens; distance from an arterial side branch; distance from an venous side branch; arterial flow; venous flow; oxygen content in artery; oxygen content in vein; wall thickness of artery; wall thickness of vein; degree of calcification of artery; degree of calcification of vein; geometric relationship between the artery and vein lumens at the fistula site; hemodynamic factors; other parameters; and combinations thereof.
Artery 130 includes, in closest proximity to skin 105 , arterial wall 131 . Vein 120 includes, in closest proximity to artery 130 , venous wall 121 . At the intended fistula location 111 of the patient, the vessels may lie in various geometric configurations, such as the geometry of FIGS. 3 a through 3 f wherein the first vessel is relatively “on top” of the second vessel such that the lumen of the first vessel lies relatively proximate the shortest line between the lumen of the second vessel at the fistula location and the surface of the patient's skin. In alternative fistula locations, the vessels may lie in a more “side-to-side” configuration. When inserted, the elongate body of outer sheath 30 is positioned to lie relatively in the plane defined by the lumens of the two vessels near the intended fistula location. While maintaining position within this plane, the fistula creation device can be inserted at an angle relatively perpendicular to the surface of the patient's skin, or at a smaller angle as is shown in FIG. 3 a , such as an angle between 20 and 80 degrees. This insertion angle may be chosen by the clinician to form the resultant fistula angular geometry between the two vessels, such as at a small insertion angle to correspond to a similarly small angle between the lumen of the first vessel and the lumen of the fistula. Such a small angle between the first vessel lumen and the fistula lumen may be desirous to reduce turbulent flow through the fistula. In alternative embodiments, an insertion angle approximating ninety degrees may be chosen, such as to minimize the length of the resultant fistula. Vein 120 is preferably a vein located in a limb of the patient, such as a vein selected from the group consisting of: saphenous vein; femoral vein; iliac vein; popliteal vein; brachial vein; basilic vein; cephalic vein; medial forearm vein; medial cubital vein; axillary vein; and jugular vein. Artery 130 is preferably an artery in a limb of the patient, such as an artery selected from the group consisting of: axillary artery; brachial artery; ulnar artery; radial artery; profundal artery; femoral artery; iliac artery; popliteal artery; carotid artery.
Referring now specifically to FIG. 3 a , a fistula creation device is positioned with its distal end near an intended skin puncture site and includes outer sheath 30 with distal end 31 . Outer sheath 30 is preferably constructed of a biocompatible catheter material, such materials and construction methods described in detail hereabove. Extending beyond distal end 31 is the distal end of a slidable needle assembly including needle tip 51 and guidewire lumen 53 . The needle assembly is preferably constructed of a metal or metal alloy such as stainless steel or Nitinol, and needle tip 51 is a sharpened, beveled tip.
Referring now to FIG. 3 b , needle tip 51 has been advanced through skin 105 , through artery wall 31 , and into the lumen of artery 130 . Distal end 31 of outer sheath 30 has also passed through skin 105 without any significant displacement between needle tip 51 and distal end 31 , either by a releasable fixation device, not shown but integral to the fistula creation device, or by stabilization of both the outer sheath 30 and the needle assembly by the operator. Referring now to FIG. 3 c , needle tip 51 has been advanced out of artery 130 , through venous wall 121 and into the lumen of vein 120 . Similar to the advancement shown in FIG. 3 b , there has been no relative displacement between needle tip 51 and distal end 31 of outer sheath 30 , such that distal end 31 has also advanced into the lumen of vein 120 . Guidewire 80 has been advanced from the proximal end of the fistula creation device, through guidewire lumen 53 and down the lumen of vein 120 . Referring now to FIG. 3 d , the needle assembly has been retracted such needle tip 51 has moved proximal to outer sheath 30 distal end 31 , while leaving guidewire 80 deep seated into vein 120 .
Referring now to FIG. 3 e , a self-expanding anastomotic implant, clip 60 , is partially deployed out of distal end 31 of outer sheath 30 , such that two tensioning arms 61 and two stabilizing arms 62 have been released from being constrained within outer sheath 30 . Clip 60 has been partially deployed through one or more actions including: pushing clip 60 out of outer sheath 30 via advancement of a core contained within outer sheath 30 ; retracting sheath 30 such as while maintaining the longitudinal position of clip 60 ; or by a combination of these two actions. While clip 60 is partially deployed, the fistula creation device is retracted to a position wherein one or more of tensioning arms 61 are in firm contact with venous wall 121 , position not shown. Clip 60 is then fully deployed such as by retraction of sheath 30 , advancement of clip 60 , or a combination of the two actions. Referring now to FIG. 3 f , clip 60 has been fully deployed such that fistula 110 is scaffolded by clip 60 , the four tensioning arms 61 placing vein 120 and artery 130 in tension at a location neighboring fistula 110 , and stabilization arms 62 stabilizing clip 60 in the vessels to prevent twisting or other clip 60 migrations. Clip 60 is preferably configured such that fistula 110 has an oval cross-section, with a major axis at least twenty percent greater than the minor axis of the oval. In a preferred embodiment, the major axis has a diameter larger than either vein 120 or artery 130 's luminal diameter. In an alternative embodiment, clip 60 's construction geometry causes fistula 110 to have a circular cross section.
Shown in FIG. 3 f , the fistula creation device is being withdrawn, such that distal end 31 of outer sheath 30 is almost removed from entering skin 105 . Guidewire 80 remains in place, such that one or more additional devices can be placed over-the-wire and easily access either the artery 130 or venous 120 side of fistula 110 . These subsequent over-the-wire devices, described in detail in reference to FIG. 2 d , can be used to assess the fistula such as an ultrasound catheter to visualize the fistula, or a Doppler ultrasound catheter to measure fistula flow. The over-the-wire devices can be used to modify the fistula such as to modify the flow rate through the fistula, or to otherwise improve the therapeutic benefit of the fistula such as to increase the long-term patency of the fistula or to minimize adverse side effects of the fistula. In a preferred embodiment, an over-the-wire or other procedure is performed to measure flow through the fistula. If inadequate flow is determined, a flow modification procedure may be performed, such as an over-the-wire flow modification procedure utilizing an inflatable balloon or a tissue removing device to increase fistula flow. In a preferred embodiment, the inflatable balloon has a non-circular geometry which corresponds to a fistula created with a non-circular geometry. The balloon may be integral to the fistula creation device, or a separate over-the-wire catheter, and may be inflated to apply force to clip 60 , or a second implant, all not shown. Other flow modification procedure may also be performed, such as procedures which place implants, within or external to the flow path, to increase or decrease fistula flow to maximize therapeutic benefit and/or reduce adverse side effects. Other flow modification procedures that may be performed include application of an agent such as an anti-biotic, anti-thrombogenic or anti-proliferative agent, or delivery of energy such as radiation delivery to prevent neointimal growth.
The method and device of FIGS. 3 a through 3 f are used to create a fistula for therapeutic benefit such as to treat a patient with COPD. The fistula can be created for various purposes such as: increasing the oxygen content of venous blood supplying a lung of the patient, increase the oxygen content of arterial blood; and/or decreasing systemic vascular resistance. The fistula can be created for an acute period less than twenty-four hours, a sub-chronic period between twenty-four hours and thirty days, as well as for a chronic period longer than thirty days. The fistula preferably provides a flow of blood from the arterial system to the venous system of greater than 5 ml/min, typically greater than 50 ml/min. Clip 60 provides one or more functions including but not limited to: scaffolding an opening between the first vessel and the second vessel; reducing neointimal proliferation into the fistula flow path; preventing tissue from protruding into the fistula flow path; placing a portion of the first vessel wall in tension with the tissue of the second vessel wall; reducing bleeding of the tissue neighboring the fistula; enhancing healing of the tissue neighboring the fistula; and combinations thereof. While clip 60 has been described as a self-expanding device such as a resiliently biased Nitinol component, anastomotic implants that are plastically deformable or include both self-expanding sections and balloon expandable portions are also preferred. In an alternative embodiment, clip 60 includes a covering, such as a covering that surrounds the interior of the tissue within the fistula between the artery and vein lumens. The covering is a biocompatible material such as polytetrafluoroethylene; Dacron; Nitinol; stainless steel; or combinations thereof. In another alternative embodiment, clip 60 includes an agent, such as an agent that is eluded over time including anti-bacterial, anti-thrombogenic and/or anti-prolific agents. While, the method of FIGS. 3 a through 3 f illustrate an artery to vein connection method, a vein to artery approach is also a preferred method of this invention.
The device and method of FIGS. 3 a through 3 f create an initial puncture through the skin of the patient, subsequently penetrating into and through the first vessel, and into the lumen of the second vessel. In an alternative, also preferred embodiment, not shown, a standard vessel introducer and sheath is utilized, making the initial puncture through the skin of the patient and into the first vessel. The fistula creation device distal end is then inserted into the sheath, passing through the skin and into the first vessel. The fistula creation device distal end exits the end of the sheath and further exits the lumen of the first vessel at the intended fistula location site by penetrating through the first vessel wall, and enters the lumen of the second vessel by penetrating through the second vessel wall. The intended fistula location may be proximate the site that the vessel introducer entered the first vessel, or at a location remote from this site, such as at a location greater than 20 mm from the first vessel entry site. Fistulas may be created remote from the first vessel entry site by intraluminally advancing the introducer sheath and/or the fistula creation device down the lumen of the first vessel prior to the distal end of the fistula creation device exiting the first vessel lumen and penetrating into the second vessel.
Referring now to FIGS. 4 a and 4 b , a method and system for creating a fistula is shown in which an operator utilizes a fistula creation device and ultrasound visualization system in combination. A cross sectional view of a patient's anatomy at a proposed fistula location 111 is depicted wherein artery 130 is directly above vein 120 in relation to skin surface 105 . Intended fistula location 111 may be determined using one or more visualization techniques including but not limited to: angiography; venography; extra-vascular ultrasound; intravascular ultrasound; and MRI. Intended fistula location 111 may be determined using one or more flow measurement techniques such as Doppler ultrasound. The intended fistula location 111 may be selected based on parameters selected from the group consisting of: first vessel diameter; second vessel diameter; artery diameter; vein diameter; ratio of artery to vein diameter; distance between the artery and vein lumens; geometric relationship between the artery and vein lumens; distance from an arterial side branch; distance from an venous side branch; arterial flow; venous flow; oxygen content in artery; oxygen content in vein; wall thickness of artery; wall thickness of vein; degree of calcification of artery; degree of calcification of vein; geometric relationship between the artery and vein lumens at the fistula site; hemodynamic factors; other parameters; and combinations thereof.
Artery 130 includes, in closest proximity to skin 105 , arterial wall 131 . Vein 120 includes, in closest proximity to artery 130 , venous wall 121 . While vein 120 and artery 130 are shown in a line relatively perpendicular to skin 105 , adjusting the orientation of outer sheath 30 can not only vary insertion angles, but also accommodate anatomies with vessels in a relatively side-by-side configuration (relatively equidistant from skin surface 105 ) as has been described hereabove in reference to FIGS. 3 a through 3 f . In a preferred method, the fistula creation device enters the skin at an angle relatively perpendicular to skin 105 . In another preferred embodiment, the fistula creation device penetrated the skin at an angle between 20 and 80 degrees relative to the surface of the skin 105 . Vein 120 is preferably a vein located in a limb of the patient, such as a vein selected from the group consisting of: saphenous vein; femoral vein; iliac vein; popliteal vein; brachial vein; basilic vein; cephalic vein; medial forearm vein; medial cubital vein; axillary vein; and jugular vein. Artery 130 is preferably an artery in a limb of the patient, such as an artery selected from the group consisting of: axillary artery; brachial artery; ulnar artery; radial artery; profundal artery; femoral artery; iliac artery; popliteal artery; carotid artery.
Referring now to specifically to FIG. 4 a , a fistula creation device is positioned with its distal end at an intended fistula site 111 . The fistula creation device includes outer sheath 30 , which is preferably constructed of a biocompatible catheter material, such materials and construction methods described in detail hereabove. Extending beyond distal end 31 of outer sheath 30 is the distal end of a slidable needle assembly including needle tip 51 and guidewire lumen 53 . The needle assembly is preferably constructed of a metal or metal alloy such as stainless steel or Nitinol, and needle tip 51 is a sharpened, beveled tip. Needle tip 51 has been advanced through skin 105 , through artery wall 31 , and into the lumen of artery 130 residing near intended fistula site 111 . Distal end 31 of outer sheath 30 has also passed through skin 105 without any significant displacement between needle tip 51 and distal end 31 , either by a releasable fixation device, not shown but integral to the fistula creation device, or by stabilization of both the outer sheath 30 and the needle assembly by the operator.
Also shown in FIG. 4 a is ultrasound probe 71 , which is positioned relatively orthogonal to the surface of skin 105 , and preferably held by an operator, operator not shown, to provide a visual cross sectional image of intended fistula site 111 , as well as artery 130 , vein 120 , and any devices crossing through the imaging plane of ultrasound probe 71 . Ultrasonic coupling gel 74 , common to external ultrasound probe use, is first placed on the skin, in the area to be visualized, to enhance the image produced by ultrasound probe 71 via improved acoustic coupling between ultrasound probe 71 and skin 105 . Referring additionally to FIG. 4 b , ultrasound probe 71 is attached to an ultrasound generator, not shown, as well as ultrasound monitor 72 which displays on imaging area 73 the cross sectional image associated with the imaging plane of FIG. 4 a . Manipulation of probe 71 , either in the position of contact with skin 105 and/or the relative angle made with the surface of skin 105 , modifies the location of the imaging plane and the associated image displayed on monitor 72 . Ultrasound probe 71 and monitor 72 are used and manipulated by an operator as a system including the fistula creation device of the present invention. This system is used to assess and pre-determine the location of intended fistula location 111 . The visualization equipment is also used to view and confirm advancements of the percutaneous devices such as catheter, sheath, inner tube and guidewire advancements; confirm device locations such as device distal end (tip) locations; and assist in other preferred fistula creation steps of the present invention in which real-time visualization of the procedure can be made available to an operator. In an alternative, also preferred embodiment, as an alternative to or in conjunction with ultrasound probe 71 , an internal ultrasound probe provides an image to monitor 72 . The internal probe, not shown, is selected from the group consisting of: an ultrasound catheter such as a rotational or phased array intravascular ultrasound catheter; an inserted probe such as a transesophageal probe; and combinations thereof.
In subsequent steps, not shown but similar to steps 3 c through 3 f hereabove, needle tip 51 will be advanced out of artery 130 , through venous wall 121 and into the lumen of vein 120 . A guidewire, not shown, will be advanced from the proximal end of the fistula creation device, through guidewire lumen 53 and down the lumen of vein 120 . The needle assembly will then be retracted such that needle tip 51 will be retracted proximal to distal end 31 of outer sheath 30 , while leaving the guidewire deep seated into vein 120 . An anastomotic implant, not shown, is deployed such as by retraction of sheath 30 while maintaining the position of the anastomotic implant. The anastomotic implant is configured such that the resultant fistula has an oval cross-section, with a major axis at least twenty percent greater than the minor axis of the oval. The fistula creation device is then withdrawn, such that distal end 31 of outer sheath 30 is almost removed from entering skin 105 . The guidewire preferably remains in place, such as through a standard vessel introducer, not shown. In a preferred embodiment, outer sheath 30 performs as the vessel introducer. Leaving the guidewire in place allows one or more additional devices to be placed over-the-wire and easily access either the venous or arterial side of the fistula. These subsequent over-the-wire devices, described in detail in reference to FIG. 2 d , can be used to assess the fistula such as an ultrasound catheter to visualize the fistula, or a Doppler ultrasound catheter to measure fistula flow. The over-the-wire devices can be used to modify the fistula such as to modify the flow rate through the fistula, or to otherwise improve the therapeutic benefit of the fistula such as to increase the long-term patency of the fistula or to minimize adverse side effects of the fistula. In a preferred embodiment, an over-the-wire or other procedure is performed to measure flow through the fistula. If inadequate flow is determined, a flow modification procedure may be performed, such as an over-the-wire flow modification procedure utilizing an inflatable balloon or a tissue-removing device to increase fistula flow. In a preferred embodiment, the inflatable balloon has a non-circular geometry that corresponds to a fistula created with a non-circular geometry. The balloon may be integral to the fistula creation device, or a separate over-the-wire catheter, and may be inflated to apply force to clip 60 , or a second implant, all not shown. Other flow modification procedure may also be performed, such as procedures that place implants, within or external to the flow path, to increase or decrease fistula flow to maximize therapeutic benefit and/or reduce adverse side effects.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
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Devices, systems and methods are disclosed for the formation of an arteriovenous fistula in the limb of the patient. Embodiments include a device for the creation, modification and maintenance of a fistula that includes an integral fistula creation assembly near its distal end that passes through the skin of the patient, through a first vessel such as an artery, and into a second vessel such as a vein. The fistula creation assembly preferably includes an anastomotic implant that is placed within the fistula to maintain long-term blood flow therethrough. The devices, systems and methods can be used to treat patients with one or more numerous ailments including chronic obstructive pulmonary disease, congestive heart failure, hypertension, hypotension, respiratory failure, pulmonary arterial hypertension, lung fibrosis and adult respiratory distress syndrome.
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CLAIM OF PRIORITY
This patent application claims the benefit of priority of Michael J. Eberle et al. U.S. Provisional Patent Application Ser. No. 61/102,216, which was filed on Oct. 2, 2009, and which is incorporated herein by reference in its entirety.
BACKGROUND
Bates et al. U.S. Pat. No. 7,245,789 is incorporated by reference herein in its entirety, including its discussion of systems and methods for minimally-invasive optical-acoustic imaging. It discusses, among other things, an imaging guidewire that includes one or more optical fibers communicating light along the guidewire. At or near a distal end of the guidewire, light is directed to a photoacoustic transducer material that provides ultrasonic imaging energy. Returned ultrasound energy is sensed by an ultrasound-to-optical transducer. A responsive signal is optically communicated to the proximal end of the guidewire, such that it can be processed to develop a 2D or 3D image.
OVERVIEW
Among other things, the present applicant has recognized the desirability of reducing or minimizing the size of a system like that described in Bates. However, the present applicant has recognized that reducing the size of the ultrasound-to-optical transducer can also change the mechanical acoustic resonance of the transducer at some ultrasound frequencies and can also result in a generally smaller output signal. Additionally, the transducer response can become dependent on the polarization of the optical signal since it is responsive to acoustic impedances in the direction of polarization. This can result in undesirable variations in the output signal conditional on the polarization direction due to different resonances in different lateral directions, for example. One approach to reduce or eliminate this effect would be to control polarization of the optical signal. However, such polarization is difficult to control or predict in a cost-effective manner. Accordingly, the present applicant has recognized, among other things, that it can be advantageous to provide an ultrasound-to-optical transducer that is relatively insensitive to optical signal polarization.
Example 1 can include an ultrasound-to-optical transducer, including an optical fiber, an ultrasound-absorptive backing configured for substantially absorbing ultrasound energy that passes beyond the optical fiber to reach the backing, and a Fiber Bragg Grating (FBG) interferometer configured for receiving the ultrasound energy and capable of modulating an optical sensing signal, in response to the ultrasound energy, substantially independent of a polarization angle of the optical sensing signal. In this example, the optical fiber can include an optical fiber diameter that is less than half of a wavelength of target ultrasound energy to be received by the transducer.
In Example 2, the subject matter of Example 1 can optionally comprise an elongated intravascular imaging assembly, comprising a proximal external portion comprising an optical signal interface and a distal portion sized and shaped and configured for internal intravascular acoustic imaging. In this example, the imaging assembly can comprise an elongated support, extending substantially from the proximal portion of the imaging assembly to the distal portion of the imaging assembly, the support configured to provide adequate length, rigidity, and flexibility to permit intravascular introduction and steering of a distal portion of the imaging assembly to a location of interest, the optical fiber, extending longitudinally and affixed along the support substantially from the proximal portion of the imaging assembly substantially to the distal portion of the imaging assembly, a transducer, located at or near a distal portion of the imaging assembly and configured as at least one of the ultrasound-to-optical transducer or an optical-to-ultrasound transducer; and the backing, located in a backing region between the transducer and the elongated support, the backing configured to attenuate ultrasound energy that reaches the backing region by at least 90%.
In Example 3, the subject matter of any one of Examples 1 or 2 can optionally be configured so that the assembly comprises a plurality of the optical fibers, extending longitudinally and affixed along the support, the fibers arranged circumferentially about a central longitudinal axis of the support, and a plurality of the transducers, wherein the transducer includes a photoacoustic material located at a peripheral portion of the optical fiber that is away from the backing.
In Example 4, the subject matter of any one of Examples 1-3 can optionally be configured such that the optical fiber diameter is less than sixty micrometers.
In Example 5, the subject matter of any one of Examples 1-4 can optionally be configured so that the backing comprises microballoons containing a gas.
In Example 6, the subject matter of any one of Examples 1-5 can optionally be configured so that the microballoons comprise about 30% to about 50% of the volume of the backing.
In Example 7, the subject matter of any one of Examples 1-6 can optionally be configured so that a thickness of the backing is between about 25 micrometers and about 100 micrometers.
In Example 8, the subject matter of any one of Examples 1-7 can optionally comprise the transducer being configured such that a peak-to-peak amplitude of an oscillating output optical bias signal modulated by the transducer varies by no more than one decibel when the polarization angle of the optical sensing signal is varied by 90 degrees.
In Example 9, the subject matter of any one of Examples 1-8 can optionally be configured such that a total birefringence induced on an optical signal with a wavelength of about 1550 nanometers transmitted within the optical fiber is less than (3×10 −6 ).
Example 10 can include (or can be combined with the subject matter of any one of Examples 1-9 to include) fabricating an ultrasound-to-optical transducer, the fabricating comprising providing an optical fiber that includes a diameter that is less than half of a wavelength of target ultrasound energy to be received by the transducer, creating a Fiber Bragg Grating (FBG) interferometer configured for receiving the ultrasound energy and capable of modulating an optical sensing signal substantially independent of a polarization of the optical sensing signal, associating an ultrasound-absorptive backing with the optical fiber, and configuring the backing for substantially absorbing ultrasound energy that passes beyond the optical fiber to reach the backing.
In Example 11, the subject matter of any one of Examples 1-10 can optionally comprise associating the backing comprising microballoons containing a gas with the fiber.
In Example 12, the subject matter of any one of Examples 1-11 can optionally comprise providing the backing comprising the microballoons that comprise about 30% to about 50% of the volume of the backing.
In Example 13, the subject matter of any one of Examples 1-12 can optionally comprise inserting the backing into a backing region between a central support structure and the optical fiber, wherein both the support structure and the fiber extend longitudinally, the backing region being bounded laterally by a tubular sheath.
In Example 14, the subject matter of any one of Examples 1-13 can optionally comprise conforming the backing to the external surface of a central support structure, wherein both the support structure and the fiber extend longitudinally.
In Example 15, the subject matter of any one of Examples 1-14 can optionally further comprise conforming a tubular sheath to a surface of the backing that is away from the support structure.
Example 16 can include (or can be combined with the subject matter of any one of Examples 1-15 to include) receiving ultrasound energy with an optical fiber, the optical fiber including a diameter that is less than half of a wavelength of the ultrasound energy, and using the ultrasound energy to modulate an optical sensing signal substantially independent of a polarization of the optical sensing signal.
In Example 17, the subject matter of any one of Examples 1-16 can optionally comprise using the ultrasound energy to modulate the optical sensing signal substantially independent of the polarization of the optical sensing signal comprises generating a modulated output optical signal with a peak-to-peak amplitude that varies by no more than one decibel when a polarization angle of the optical sensing signal is varied by 90 degrees.
In Example 18, the subject matter of any one of Examples 1-17 can optionally comprise using an ultrasound-absorptive backing to substantially attenuate ultrasound energy that passes beyond the optical fiber to reach the backing.
In Example 19, the subject matter of any one of Examples 1-18 can optionally comprise using the ultrasound-absorptive backing to attenuate ultrasound energy that passes beyond the optical fiber to reach the backing by at least 90%.
In Example 20, the subject matter of any one of Examples 16-19 can optionally comprise forming an image of a region within a living body using information from a modulated output optical signal.
These examples can be combined with each other in any permutation or combination and or with other subject matter disclosed herein. This overview is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.
FIG. 1 is a cross-sectional side view illustrating generally, by way of example, but not by way of limitation, an example of an FBG strain sensor in an optical fiber.
FIG. 2 is a cross-sectional side view illustrating generally, by way of example, but not by way of limitation, an example of an FBG grating interferometer sensor.
FIG. 3 is a cross-sectional schematic diagram illustrating generally an example of an acousto-optic transducer.
FIG. 4 is a cross-sectional schematic diagram illustrating generally another example of an FBG strain sensor in an optical fiber.
FIG. 5 is a schematic diagram that illustrates generally an example of a side view of a distal portion of a guidewire.
FIG. 6 is a schematic diagram that illustrates generally an example of a cross-sectional side view of a distal portion of a guidewire.
FIG. 7 is a schematic diagram that illustrates generally an example of a cross-sectional end view of a proximal portion of a guidewire.
FIG. 8 is a schematic diagram that illustrates generally an example of a cross-sectional end view of a distal portion of a guidewire.
FIG. 9 is a cross-sectional end view that illustrates generally an example of a guidewire assembly at a location of a transducing window.
DETAILED DESCRIPTION
1. Examples of Fiber Bragg Grating Strain Sensors
FIG. 1 is a cross-sectional side view illustrating generally, by way of example, but not by way of limitation, an example of a strain-detecting or pressure-detecting acoustic-to-optical FBG sensor 100 in an optical fiber 105 . FBG sensor 100 senses acoustic energy received from a nearby area to be imaged, and transduces the received acoustic energy into an optical signal within optical fiber 105 . In the example of FIG. 1 , FBG sensor 100 can include Bragg gratings 110 A-B in an optical fiber core 115 , such as surrounded by an optical fiber cladding 120 . Bragg gratings 110 A-B can be separated by a strain or pressure sensing region 125 , which, in an example, can be about a millimeter in length. This example can sense strain or pressure such as by detecting a variation in length of the optical path between these gratings 110 A-B.
A Fiber Bragg Grating can be conceptualized as a periodic change in the optical refractive index of a portion of the optical fiber core 115 . Light of specific wavelengths traveling down such a portion of core 115 will be reflected; the period (distance) 130 of the periodic change in the optical index determines the particular wavelengths of light that will be reflected. The degree of optical index change and the length 135 of the grating determine the ratio of light reflected to that transmitted through the grating 110 A-B.
FIG. 2 is a cross-sectional side view illustrating generally, by way of example, but not by way of limitation, an operative example of an interferometric FBG sensor 100 . The example of FIG. 2 can include two FBG mirrors 110 A-B, which can be both partially reflective such as for a specific range of wavelengths of light passing through fiber core 115 . Generally, the reflectivity of each FBG will be substantially similar, but can differ for particular implementations. This interferometric arrangement of FBGs 110 A-B can be capable of discerning the “optical distance” between FBGs 110 A-B with extreme sensitivity. The “optical distance” can be a function of the effective refractive index of the material of fiber core 115 as well as the length 125 between FBGs 110 A-B. Thus, a change in the refractive index can induce a change in optical path length, even though the physical distance 125 between FBGs 110 A-B has not substantially changed.
An interferometer, such as FBG sensor 100 , can be conceptualized as a device that measures the interference between light reflected from each of the partially reflective FBGs 110 A-B. When the optical path length between the FBG minors 110 A-B is an exact integer multiple of the wavelength of the optical signal in the optical fiber core 115 , then the light that passes through the FBG sensor 100 will be a maximum and the light reflected will be a minimum, so the optical signal is substantially fully transmitted through the FBG sensor 100 . This addition or subtraction can be conceptualized as interference. The occurrence of full transmission or minimum reflection can be called a “null” and occurs at a precise wavelength of light for a given optical path length. Measuring the wavelength at which this null occurs can yield an indication of the length of the optical path between the two partially reflective FBGs 110 A-B. In such a manner, an interferometer, such as FBG sensor 100 , can sense a small change in distance, such as a change in the optical distance 125 between FBGs 110 A-B resulting from received ultrasound or other received acoustic energy. This arrangement can be thought of as a special case of the FBG Fabry-Perot interferometer, sometimes more particularly described as an Etalon, because the distance 125 between the FBGs 110 A-B is substantially fixed.
The sensitivity of an interferometer, such as FBG sensor 100 , can depend in part on the steepness of the “skirt” of the null in the frequency response. The steepness of the skirt can be increased by increasing the reflectivity of the FBGs 100 A-B, which also increases the “finesse” of the interferometer. The present applicant has recognized, among other things, that increasing the finesse or steepness of the skirt of FBG sensor 100 can increase the sensitivity of the FBG sensor 100 to the reflected ultrasound signals within a particular wavelength range but can decrease the dynamic range. As such, keeping the wavelength of the optical sensing signal within the wavelength range can be advantageous. In an example, a closed-loop system can monitor a representative wavelength (e.g., the center wavelength of the skirt of the filtering FBG sensor 100 ) and can adjust the wavelength of an optical output laser to remain substantially close to the center of the skirt of the filter characteristic of the FBG sensor 100 as forces external to the optical fiber 105 , such as bending and stress, cause the center wavelength of the skirt of the filter characteristic of the FBG sensor 100 to shift.
In an example, such as illustrated in FIG. 2 , the interferometric FBG sensor 100 can cause interference between that portion of the optical beam that is reflected off the first partially reflective FBG 110 A with that reflected from the second partially reflective FBG 110 B. The wavelength of light where an interferometric null will occur can be very sensitive to the “optical distance” between the two FBGs 110 A-B. The interferometric FBG sensor 100 of FIG. 2 can provide another very practical advantage. In this example, the two optical paths along the fiber core 115 are the same, except for the sensing region between FBGs 110 A-B. This shared optical path ensures that any optical changes in the shared portion of optical fiber 105 will have substantially no effect upon the interferometric signal; only the change in the sensing region 125 between FBGs 110 A- 110 B is sensed. However, the present applicant has recognized, among other things, that this sensing can be affected by birefringence of the optical fiber within FBG sensor 100 .
Optical birefringence is a measure of the difference in refractive index of an optical medium for light of different polarizations. The polarization of light can be defined as the orientation of the electric vector of the electromagnetic light wave. Birefringence between two at least partially reflective FBGs, such FBGs 110 A-B, can cause different beams of light with different polarizations to effectively travel slightly different optical path lengths between the FBGs 110 A-B. Therefore, a combination of birefringence between the at least partially reflective FBGs 110 A-B and a shift in the polarization of the optical signal within the optical fiber core 115 can cause a shift in the exact wavelength of the null of the FBG sensor 100 . When light is split between different polarization states, the light will be reflected or transmitted from different parts of the skirt of the null, which can lead to fading of the optically transduced signal. There are many possible states of polarization, such as linear, circular, and elliptical, but the worst signal fading generally occurs when the optical signal is split equally between linear polarization states that are orthogonally aligned. With this in mind, the present applicant has recognized, among other things, that birefringence should be reduced or otherwise addressed, if possible.
The present applicant has also recognized that there can be two main sources of optical birefringence within the FBG sensor 100 . The first source is the intrinsic birefringence of the optical fiber 105 . The intrinsic birefringence is determined mostly during the manufacturing of the optical fiber 105 and is generally a function of the level of geometric symmetry, the uniformity of dopant distribution, and the level of stress in the fiber core 115 during the drawing of the fiber core 115 .
The second source of optical birefringence in the FBG sensor 100 is the process of writing the FBGs 110 A and 110 B. The present applicant has also recognized that the birefringence induced by the writing of FBGs 110 A and 110 B can be reduced such as by controlling one or more aspects of the writing process, such as the polarization of the writing laser, the laser pulse energy, the writing exposure time, the amount of hydrogen or deuterium in the fiber during writing, or any combination thereof.
2. Examples of FBG Acoustic-to-Optical Transducers
In an example, an FBG sensor 100 senses pressure or strain such as generated by ultrasound or other acoustic energy received from a nearby imaging region to be visualized and, in response, modulates an optical sensing signal in an optical fiber. Increasing the sensitivity of the FBG sensor 100 can provide improved imaging. A first example of increasing sensitivity is to increase the amount of strain induced in the FBG sensor 100 for a given dynamic pressure provided by the acoustic energy. A second example is to increase the modulation of the optical signal for a given change in strain of the FBG sensor 100 . Any combination of the techniques of these first and second examples can also be used.
One technique of increasing the strain induced in the FBG sensor 100 is to configure the physical attributes of the FBG sensor 100 such as to increase the degree of strain for a given externally-applied acoustic field. In an example, the FBG sensor 100 can be shaped so as to increase the strain for a given applied acoustic pressure field. FIG. 3 is a cross-sectional schematic diagram illustrating such an example in which the FBG sensor 100 is shaped such that it mechanically resonates at or near the frequency of the acoustic energy received from the nearby imaging region, thereby resulting in increased strain. In the example of FIG. 3 , all or a portion of the strain sensing region between FBGs 110 A-B is selected to provide a thickness 300 that promotes such mechanical resonance of the received acoustic energy, thereby increasing the resulting strain sensed by FBG sensor 100 . In an example, such as illustrated in FIG. 3 , this can be accomplished by grinding or otherwise removing a portion of fiber cladding 120 , such that the remaining thickness of fiber core 115 or fiber cladding 120 between opposing planar (or other) surfaces is selected to mechanically resonate at or near the frequency of the acoustic energy received from the nearby imaging region.
In an example, mechanical resonance can be obtained by making the thickness 300 of the strain sensing region substantially the same thickness as ½ the acoustic wavelength (or an odd integer multiple thereof) in the material(s) of FBG sensor 100 at the acoustic center frequency of the desired acoustic frequency band received from the imaging region. In other examples, such as for other materials, the thickness 300 can be selected to match a different proportion of the acoustic wavelength that obtains the desired mechanical resonance for that material. Calculations indicate that obtaining such mechanical resonance can increase the strain sensitivity by a factor of 2 or more over that of a sensor that is not constructed to obtain such mechanical resonance.
In a third example, a coating 305 can be applied to the FBG sensor 100 such as to increase the acoustic pressure as seen by the FBG sensor 100 over a band of acoustic frequencies, such as for improving its sensitivity over that band. The difference between the mechanical characteristics of water (or tissue and/or blood, which is mostly comprised of water) and glass material of the optical fiber 105 carrying the FBG sensor 100 is typically so significant that only a small amount of acoustic energy “enters” the FBG sensor 100 and thereby causes strain; the remaining energy is reflected back into the biological or other material being imaged. For a particular range of acoustic frequencies, one or more coatings 305 of specific thickness 310 or mechanical properties (e.g., the particular mechanical impedance) of the coating material can be used to dramatically reduce such attenuation due to the different mechanical characteristics. An example can use quarter wave matching, providing a coating 305 of a thickness 310 that is approximately equal to one quarter of the acoustic signal wavelength received from the region being imaged. Using such matching, the sensitivity of the FBG sensor 100 , over a given band of acoustic frequencies of interest, is expected to increase by about a factor of 2.
However, for a mechanically resonant transducer, reducing the thickness of fiber cladding 120 , and therefore reducing the total size of the transducer, is limited by the wavelength of the acoustic energy to be received. In a fourth example, the thickness 300 of the strain sensing region is substantially less than half of the wavelength of the target acoustic energy. FIG. 4 is a cross-sectional schematic diagram illustrating such an example. In this example, the thickness 300 of the strain sensing region can be less than 60 micrometers. As the acoustic width of the transducer is reduced, the cross-sectional area of the transducer is reduced, and the total strain due to acoustic pressure on the transducer is reduced. Therefore, a smaller thickness 300 of the strain sensing region results in a smaller received acoustic signal, leading to reduced receive sensitivity of the FBG sensor 100 . This reduced receive sensitivity of the FBG sensor 100 can be improved by placing a backing 440 between the strain sensing region of the optical fiber 105 and a core wire 450 that can be configured to provide support, rigidity, and flexibility for the assembly. The backing 440 can include a high acoustic impedance material such as a metal or ceramic. In an example, the backing 440 can be separated from the optical fiber such as by an acoustically thin (e.g., less than a quarter wavelength thick) tubular sheath 460 . The coating 305 can also be configured, in an example, for acoustic impedance matching.
In an example, the backing 440 can be configured to reflect acoustic energy back to the strain sensing region, such as in a resonant manner, to increase the total amount of acoustic energy received by the strain sensing region and thereby increase the strain on the region. In this example, however, the receive sensitivity of FBG sensor 100 may depend on the polarization of the optical sensing signal because the backing 440 does not enhance the acoustic signal in all directions. The receive sensitivity generally is highest when the optical sensing signal is polarized parallel to an axis extending through the backing 440 and the fiber core 115 or an axis extending through the core wire 450 and the fiber core 115 . The receive sensitivity is generally lowest when the angle of the polarization of the optical sensing signal is parallel to the outline of the interface between the backing 440 and the sheath 460 , because the backing does not enhance the signal for this polarization orientation. The variable sensitivity in this example results at least partially from acoustic reflections from the backing 440 and from the core wire 450 . The present applicant has recognized, among other things, that sensitivity to polarization of the optical sensing signal should be reduced or eliminated, if possible, in an example.
In an example, the backing 440 can be configured to absorb the acoustic energy that penetrates completely through the optical fiber to reach the backing 440 . In this example, the backing 440 can be configured both to not reflect any acoustic energy back to FBG sensor 100 and also to inhibit or prevent the core wire 450 from reflecting any acoustic energy back to FBG sensor 100 . The sheath 460 in this example can be configured to not reflect any substantial amount of acoustic energy. In an illustrative example, the sheath 460 can comprise a layer of UV-curable polyester such as with a thickness of about 10 micrometers or less. The backing 440 in this illustrative example can comprise microballoons filled with gas or microballoons filled with gas mixed into a polymer matrix. In an example of a device configured for imaging within a coronary vasculature, the room for the backing 440 is very limited, and therefore it can be advantageous if the backing 440 is relatively highly acoustically absorbent with a relatively small thickness. In an example in which acoustic energy that penetrates completely through the optical fiber to reach the backing 440 is substantially absorbed by a relatively small thickness of the backing 440 , microballoons can comprise 30% to 50% of the volume of the backing 440 . With such a poymer-microballoon mixture, the backing 440 can have a thickness of as little as 50 micrometers and can be configured to be capable of attenuating acoustic energy with a frequency of 20 megahertz by 17 decibels to 23 decibels per millimeter of thickness of the backing 440 . In an example, the sensitivity of FBG sensor 100 is relatively independent of the polarization of the output optical beam within FBG sensor 100 . In an example, a peak-to-peak amplitude of the oscillating output optical sensing signal varies by no more than one decibel as the polarization of the output optical sensing signal is rotated 90 degrees. In an example, the backing 440 attenuates ultrasound energy by at least 90%.
The above examples can be combined with each other or can include more or fewer elements than are recited in the examples and can still function as described in the examples. For example, an ultrasound-to-optical transducer that is relatively insensitive to the polarization of the optical sensing signal can include an optical fiber, a backing configured to absorb ultrasound energy that goes through the optical fiber to reach the backing, and an FBG interferometer configured to modulate an optical sensing signal in response to the ultrasound energy. The optical fiber can include a thickness of the optical fiber that is less than half the wavelength of the ultrasound energy that is sensed by the transducer.
3. Examples of Guidewire Design
FIG. 5 is a schematic diagram that illustrates generally an example of a side view of a distal portion 500 of an imaging guidewire 505 or other elongated catheter (in an example, the guidewire 505 is sized and shaped and is of flexibility and rigidity such that it is capable of being used for introducing and/or guiding a catheter or other medical instrument, e.g., over the guidewire 505 within a living body). In this example, the distal portion 500 of the imaging guidewire 505 includes one or more imaging windows 510 A, 510 B, . . . , 510 N located slightly or considerably proximal to a distal tip 515 of the guidewire 505 . Each imaging window 510 includes one or more acoustic-to-optical FBG sensors 100 . In an example, the different imaging windows 510 A, 510 B, . . . , 510 N are designed for different optical wavelengths, such that particular individual windows can be addressed by changing the optical wavelength being communicated through fiber core 115 .
FIG. 6 is a schematic diagram that illustrates generally an example of a cross-sectional side view of a distal portion 600 of a guidewire 605 . In this example, the guidewire 605 can include a solid metal or other core wire 450 that can taper down in diameter (e.g., from an outer diameter of about 0.011 inches) at a suitable distance 615 (e.g., about 50 cm) from the distal tip 620 , to which the tapered-down distal end of core wire 450 can be attached. In this example, optical fibers 625 can be distributed around the outer circumference of the guidewire core 450 , and can be attached to the distal tip 620 . In this example, the optical fibers 625 can be at least partially embedded in a binder material (e.g., UV curable acrylate polymer) that bonds the optical fibers 625 to the guidewire core wire 450 or the distal tip 620 . The binder material may also contribute to the torsion response of the resulting guidewire assembly 605 . In an example, the optical fibers 625 and binder material can be overcoated with a polymer or other coating 630 , such as for providing abrasion resistance, optical fiber protection, or friction control, or a combination thereof. At least one metallic or other bulkhead 640 can be provided along the tapered portion of the core wire 450 . In an example, the optical fibers 625 and binder 635 can be attached to a proximal side of the bulkhead 640 such as near its circumferential perimeter. A distal side of the bulkhead 640 can be attached, such as near its circumferential perimeter, to a coil winding 610 that can extend further, in the distal direction, to a ball or other distal tip 620 of the guidewire 605 . In this example, the composite structure of the distal region 600 of the guidewire 605 can provide, among other things, flexibility and rotational stiffness, such as for allowing the guidewire 605 to be maneuvered to an imaging region of interest such as within a vascular or any other lumen.
FIG. 7 is a schematic diagram that illustrates generally an example of a cross-sectional end view of a proximal portion 700 of guidewire 605 , which can include core wire 450 , optical fibers 625 , binder material 635 , and outer coating 630 . In this example, but not by way of limitation, the diameter of the core 450 can be about 11/1000 inch, the diameter of the optical fibers 625 can be about (1.25)/1000 inch, and the optional outer coating 1030 can be about (0.25)/1000 inch thick.
FIG. 8 is a schematic diagram that illustrates generally an example of a cross-sectional end view of the distal portion 600 of the guidewire 605 , e.g., adjacent to the distal tip 620 . In this example, but not by way of limitation, the diameter of core wire 450 has tapered down to about 1.5/1000 inch, circumferentially surrounded by a void 800 of about the same outer diameter (e.g., about 11/1000 inch) as the core wire 450 near the proximal end 700 of the guidewire 605 . In this example, the optical fibers 625 can be circumferentially disposed in the binder material 635 around the void 800 . Binder material 635 can provide structural support. Optical fibers 625 can be optionally overlaid with the outer coating 630 .
4. Examples of Acoustic Transducer Construction
In an example, before one or more acoustic transducers are fabricated, the guidewire 605 can be assembled. FIG. 9 is a cross-sectional end view illustrating an example of a structure of such a guidewire assembly such as at a location of a transducing window 510 . An example of such assembling can include placing the tubular sheath 460 on the core wire 450 such as at the locations selected for transducing, inserting the backing 440 into a gap between the core wire 450 and the tubular sheath 460 , and binding the optical fibers 625 to the sheath 460 and the distal tip 620 or bulkhead 640 . The coating 305 , which, in an example, can include the outer coating 630 , can then optionally be layered over the optical fibers 625 . In another example of such assembling, the backing 440 can be formed to the surface of the core wire 450 such as at the locations selected for transducing, and the tubular sheath 460 can be formed to the exposed surface of the backing, such as by heat-shrinking, for example. In an example, the optical fibers 625 can each have a diameter of less than half of the wavelength of the acoustic energy that the acoustic transducers are designed to sense, although the diameter of each of the optical fibers 625 can be larger than this in other examples.
After the guidewire 605 has been assembled, the FBGs can be added to one or more portions of the optical fibers 625 , such as within the transducer windows 510 . In an example, an FBG can be created using an optical process in which a portion of the optical fiber 625 is exposed to a carefully controlled pattern of ultraviolet (UV) radiation that defines the Bragg grating. Then, a photoacoustic material or other desired overlayer can be deposited or otherwise added in the transducer windows 510 such as over the Bragg grating. Thus, in this example, the FBGs can be advantageously constructed after the optical fibers 625 have been mechanically assembled into the guidewire assembly 605 .
An FBG writing laser can be used to expose the desired portion of the optical fiber 625 to a carefully controlled pattern of UV radiation to define the Bragg grating. The FBG writing laser can be operated so as to reduce the amount of birefringence caused by the FBGs. This will reduce the dependence of the FBG sensor 100 on the polarization of the optical sensing signal that is modulated by the received acoustic energy. In an illustrative example, at least one of hydrogen or deuterium can first be optionally infused into the optical fiber core 115 . Conditions for diffusion of the gas into the fiber can be 150 atm pressure at room temperature for 1 to 10 days. Then, the optical fiber 625 can be exposed to the writing laser, such as for a time period of between about 30 seconds and about 10 minutes. In this example, the writing laser can have a pulse energy of between about 0.1 millijoules (mJ) and about 10 millijoules and can have a polarization angle that is substantially parallel to the longitudinal axis of the optical fiber core 115 .
In an illustrative example, such as in which hydrogen is not infused into the optical fiber core 115 , the optical fiber 625 can be exposed to the writing laser such as for a time period of between about 30 seconds and about 10 minutes. In this example, the writing laser can have a pulse energy of between about 0.1 millijoules and about 10 millijoules and a polarization angle that is substantially perpendicular to the longitudinal axis of the optical fiber core 115 . In either this example or the above example in which hydrogen or deuterium is first optionally infused into the optical fiber core 115 , desired portions of all layers or coverings over the fiber cladding 120 can optionally be removed before the optical fiber 625 is exposed to the writing laser.
In an example, the writing conditions can be controlled so that the FBG sensor 100 is relatively insensitive to the polarization of the output optical signal. This can include, for example, reducing the speed of writing by lowering the intensity of the UV lamp in order to reduce heating biases. In an example, the shift in the center wavelength of the skirt of the FBG sensor 100 as the polarization of the output optical sensing signal is rotated 90 degrees is less that half of the Full Width Half Maximum of the skirt of the FBG sensor 100 . In another example, a total birefringence induced on an optical signal with a wavelength of about 1550 nanometers transmitted within the optical fiber 625 is less than (3×10 −6 ).
Additional Notes
In this document, the term “minimally-invasive” refers to techniques that are less invasive than conventional surgery; the term “minimally-invasive” is not intended to be restricted to the least-invasive technique possible.
Although certain of the above examples have been described with respect to intravascular imaging (e.g., for viewing or identifying vulnerable plaque), the present systems, devices, and methods are also applicable to imaging any other body part. For example, the guidewire or other elongated body as discussed above can be inserted into a biopsy needle, laparoscopic device, or any other lumen or cavity such as for performing imaging. Moreover, such imaging need not involve insertion of an elongate body into a lumen, for example, an imaging apparatus can be wrapped around a portion of a region to be imaged.
In an example, the present systems, devices, and methods can be used to process the Doppler shift in acoustic frequency to image or measure blood flow. The operation can be similar to that described above, however, this would increase the length of the transmitted acoustic signal, and can use Doppler signal processing in the image processing portion of the control electronics. The transmitted acoustic signal can be lengthened, in an example, such as by repeatedly pulsing the transmit optical energy at the same rate as the desired acoustic frequency.
The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown and described. However, the present inventors also contemplate examples in which only those elements shown and described are provided.
All publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference(s) should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.
In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.
Method examples described herein can be machine or computer-implemented at least in part. Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, the code may be tangibly stored on one or more volatile or non-volatile computer-readable media during execution or at other times. These computer-readable media may include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.
The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
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An imaging guidewire can include one or more optical fibers communicating light along the guidewire. At or near its distal end, one or more blazed or other Fiber Bragg Gratings (FBGs) can direct light to a photoacoustic transducer material that provides ultrasonic imaging energy. Returned ultrasound can be sensed by an FBG sensor. A responsive signal can be optically communicated to the proximal end of the guidewire, and processed such as to develop a 2D or 3D image. In an example, the guidewire outer diameter can be small enough such that an intravascular catheter can be passed over the guidewire. To minimize the size of the guidewire, an ultrasound-to-acoustic transducer that is relatively insensitive to the polarization of the optical sensing signal can be used. The ultrasound-to-optical transducer can be manufactured so that it is relatively insensitive to the polarization of the optical sensing signal.
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This is a continuation application to U.S. Pat. No. 5,186,670, filed as U.S. patent application Ser. No. 07/844,369, on Mar. 2, 1992.
FIELD OF THE INVENTION
This invention relates to field emission devices, and more particularly to processes for creating gate and focus ring structures which are self-aligned to the emitter tips using chemical mechanical planarization (CMP) and etching techniques.
BACKGROUND OF THE INVENTION
Cathode ray tube (CRT) displays, such as those commonly used in desk-top computer screens, function as a result of a scanning electron beam from an electron gun, impinging on phosphors on a relatively distant screen. The electrons increase the energy level of the phosphors. When the phosphors return to their normal energy level, they release the energy from the electrons as a photon of light, which is transmitted through the glass screen of the display to the viewer.
Flat panel displays have become increasingly important in appliances requiring lightweight portable screens. Currently, such screens use electroluminescent or liquid crystal technology. A promising technology is the use of a matrix-addressable array of cold cathode emission devices to excite phosphor on a screen.
In U.S. Pat. No. 3,875,442, entitled "Display Panel," Wasa et. al. disclose a display panel comprising a transparent gas-tight envelope, two main planar electrodes which are arranged within the gas-tight envelope parallel with each other, and a cathodoluminescent panel. One of the two main electrodes is a cold cathode, and the other is a low potential anode, gate, or grid. The cathode luminescent panel may consist of a transparent glass plate, a transparent electrode formed on the transparent glass plate, and a phosphor layer coated on the transparent electrode. The phosphor layer is made of, for example, zinc oxide which can be excited with low energy electrons. This structure is depicted in FIG. 1.
Spindt, et. al. discuss field emission cathode structures in U.S. Pat. Nos. 3,665,241, and 3,755,704, and 3,812,559. To produce the desired field emission, a potential source is provided with its positive terminal connected to the gate, or grid, and its negative terminal connected to the emitter electrode (cathode conductor substrate). The potential source may be made variable for the purpose of controlling the electron emission current. Upon application of a potential between the electrodes, an electric field is established between the emitter tips and the lo potential anode grid, thus causing electrons to be emitted from the cathode tips through the holes in the grid electrode.
An array of points in registry with holes in low potential anode grids are adaptable to the production of cathodes subdivided into areas containing one or more tips from which areas emissions can be drawn separately by the application of the appropriate potentials thereto.
The clarity, or resolution, of a field emission display is a function of a number of factors, including emitter tip sharpness, alignment and spacing of the gates, or grid openings, which surround the tips, pixel size, as well as cathode-to-gate and cathode-to-screen voltages. These factors are also interrelated. Another factor which effects image sharpness is the angle at which the emitted electrons strike the phosphors of the display screen.
The distance (d) that the emitted electrons must travel from the baseplate to the faceplate is typically on the order of several hundred microns The contrast and brightness of the display are optimized when the emitted electrons impinge on the phosphors located on the cathodoluminescent screen, or faceplate, at a substantially 90° angle. However, the contrast and brightness of the display are not currently optimized due to the fact that the initial electron trajectories assume a substantially conical pattern having an apex angle of roughly 30°, which emanates from the emitter tip. In addition, the space-charge effect results in coulombic repulsion among emitted electrons, which tends to further dispersion within the electron beam, as depicted in FIG. 1.
U.S. Pat. No. 5,070,282 entitled, "An Electron Source of the Field Emission Type," discloses a "controlling electrode" placed downstream of the "extracting electrode." U.S. Pat. No. 4,943,343 entitled, "Self-aligned Gate Process for Fabricating Field Emitter Arrays," discloses the use of photoresist in the formation of self-aligned gate structures.
SUMMARY OF THE INVENTION
The object of the present invention is to enhance image clarity on flat panel displays through the use of self-aligned gate and focus ring structures in the fabrication of cold cathode emitter tips. Chemical mechanical planarization (CMP) and selective etching techniques are key elements of the fabrication process.
The focus rings of the present invention, which are similar to the focusing structures of CRTs, function to collimate the emitted electrons so that the beam impinges on a smaller spot on the display screen, as seen in FIG. 2.
One advantage of the process of the present invention is that it allows for the incorporation of focus rings into a cold cathode fabrication process, which provides enhanced collimation of electrons emitted from the cathode emitter tips, and results in improved display contrast and clarity.
Another advantage of the process of the present invention is the fabrication of the focus rings is accomplished in a self-aligned manner, which greatly reduces process variability, and decreases manufacturing costs.
BRIEF DESCRIPTION OF THE DRAWINGS
The process of the present invention will be better understood by reading the following description of nonlimitative embodiments, with reference to the attached drawings, wherein like parts in each of the several figures are identified by the same reference character, and which are briefly described as follows:
FIG. 1 is a cross-sectional schematic drawing of a flat panel display showing a field emission cathode which lacks the self-aligned focus rings of the present invention;
FIG. 2 is the flat panel display shown in FIG. 1, further depicting the added focus ring structures of the present invention;
FIG. 3 shows a field emission cathode, having a substantially conical emitter tip, on which has been deposited a first insulating layer, a conductive layer, a second insulating layer, a focus electrode layer, and a buffer layer according to the present invention;
FIG. 3A shows the field emission cathode of FIG. 3, further illustrating multiple insulating layers and focus electrode layers;
FIG. 4 shows the multi-layer structure of FIG. 3 after it has undergone chemical mechanical planarization (CMP), according to the present invention;
FIG. 5 shows the structure of FIG. 4, after a first etching, according to the present invention;
FIG. 6 shows the structure of FIG. 5, after a second etching, according to the present invention;
FIG. 7 shows the structure of FIG. 6, after wet etching, according to the present invention; and
FIG. 7A shows the structure of FIG. 3A, after wet etching according to the present invention;
FIG. 8 is a flow diagram of the steps involved in the formation of self-aligned gate and focus-ring structures according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a field emission display employing a cold cathode is depicted. The substrate 11 can be comprised of glass, for example, or any of a variety of other suitable materials. In the preferred embodiment, a single crystal silicon layer serves as a substrate 11 onto which a conductive material layer 12, such as doped polycrystalline silicon has been deposited. At a field emission site location, a conical micro-cathode 13 (also referred to herein as an emitter tip) has been constructed on top of the substrate 11. Surrounding the micro-cathode 13, is a low potential anode gate structure 15. When a voltage differential, through source 20, is applied between the cathode 13 and the gate 15, an electron stream 17 is emitted toward a phosphor coated screen 16. The screen 16 functions as the anode. The electron stream 17 tends to be divergent, becoming wider at greater distances from the tip of cathode 13. The electron emission tip 13 is integral with the single crystal semiconductor substrate 11, and serves as a cathode conductor. Gate 15 serves as a low potential anode or grid structure for its respective cathode 13. A dielectric insulating layer 18 is deposited on the conductive cathode layer 12. The insulator 18 also has an opening at the field emission site location.
The cathode structure of FIG. 2 is similar to FIG. 1. However, beam collimating focus ring structures 19 fabricated by the process of the present invention, are also depicted. The focus rings 19 collimate the electron beam 17 emitted from each cathode so as to reduce the area of the spot where the beam impinges on the phosphor coated screen 16, thereby improving image resolution.
The invention can best be understood with reference to FIGS. 3-8 of the drawings which depict the initial, intermediate and final structures produced by a series of manufacturing steps according to the invention.
There are several methods by which to form the electron emission tips (Step A of FIG. 8) employed in the process of the present invention. Examples of such methods are presented in U.S. Pat. No. 3,970,887 entitled "Microstructure Field Emission Electron Source."
In practice, a single crystal P-type silicon wafer having formed therein (by suitable known doping pretreatment) a series of elongated, parallel extending opposite N-type conductivity regions, or wells. Each N-type conductivity strip has a width of approximately 10 microns, and a depth of approximately 3 microns. The spacing of the strips is arbitrary and can be adjusted to accommodate a desired number of field emission cathode sites to be formed on a given size silicon wafer substrate. (Processing of the substrate to provide the P-type and N-type conductivity regions may be by may well-known semiconductor processing techniques, such as diffusion and/or epitaxial growth.) If desired the P-type and N-type regions, of course, can be reversed through the use of a suitable starting substrate and appropriate dopants.
The wells, having been implanted with ions will be the site of the emitter tips. A field emission cathode microstructure can be manufactured using an underlying single crystal, semiconductor substrate. The semiconductor substrate may be either P or N-type and is selectively masked on one of its surfaces where it is desired to form field emission cathode sites. The masking is done in a manner such that the masked areas define islands on the surface of the underlying semiconductor substrate. Thereafter, selective sidewise removal of the underlying peripheral surrounding regions of the semiconductor substrate beneath the edges of the masked island areas results in the production of a centrally disposed, raised, single crystal semiconductor field emitter tip in the region immediately under each masked island area defining a field emission cathode site. It is preferred that the removal of underlying peripheral surrounding regions of the semiconductor substrate be closely controlled by oxidation of the surface of the semiconductor substrate surrounding the masked island areas with the oxidation phase being conducted sufficiently long to produce sideways growth of the resulting oxide layer beneath the peripheral edges of the masked areas to an extent required to leave only a non-oxidized tip of underlying, single crystal substrate beneath the island mask. Thereafter, the oxide layer is differentially etched away at least in the regions immediately surrounding the masked island areas to result in the production of a centrally disposed, raised, single crystal semiconductor field emitter tip integral with the underlying single, crystal semiconductor substrate at each desired field emission cathode site.
Before beginning the gate formation process, the tip of the electron emitter may be sharpened through an oxidation process (Step A' of FIG. 8). The surface of the silicon wafer (Si) 11 and the emitter tip 13 are oxidized to produce an oxide layer of SiO 2 , which is then etched to sharpen the tip. Any conventional, known oxidation process may be employed in forming the SiO 2 , and etching the tip.
The next step (Step B of FIG. 8) is the deposition of a conformal insulating material which is selectively etchable with respect to the conductive gate material. In the preferred embodiment, a silicon dioxide layer 18 is used. Other suitable selectively etchable materials, including but not limited to, silicon nitride and silicon oxynitride may also be used. The thickness of this first insulating layer will substantially determine both the gate 15 to cathode 13 spacing, as well as the gate 15 to substrate spacing 11. Hence, the insulating layer must be as thin as possible, since small gate 15 to cathode 13 distances result in lower emitter drive voltages, at the same time, the insulating layer must be large enough to prevent the oxide breakdown which occurs if the gate is not adequately spaced from the cathode conductor 12. The oxide insulating layer 18, as shown in FIG. 3, is a conformal insulating layer. The oxide is deposited on the emitter tip 13 in a manner such that the oxide layer conforms to the preferably conical shape of the cathode emitter tip 13.
The next step in the process (Step C of FIG. 8) is the deposition of the conductive gate material 15 (FIG. 3). The gate is formed from a conductive layer. The conductive material layer 15 may comprise a metal, such as chromium or molybdenum, but the preferred material for this process is deemed to be doped polysilicon or silicided polysilicon.
At this stage in the fabrication, Step E' of FIG. 8) a buffer material 21 may be deposited to prevent the undesired etching of the lower-lying portions of the focus electrode material layer 19 during the chemical mechanical polishing (CMP) step (Step F of FIG. 8) which follows. It should be emphasized that the deposition of a buffering layer 21 is an optional step. A suitable buffering material is a thin layer of Si 3 N 4 . The nitride buffer layer 21 has the effect of enhancing the strength of the tip 13, which is one advantage of performing this optional step. The buffering layer 21 substantially impedes the progress of the CMP into the layer on which the buffering material 21 is deposited.
The next process step (Step E of FIG. 8), a focus electrode layer 19 is deposited (FIG. 3). The focus rings 19 (FIG. 2) will be formed from the focus electrode layer 19. The focus electrode material layer 19 is also a conductive layer which may be comprised of a metal, such as chromium or molybdenum, but as in the case with the conductive gate material layer 15, the preferred material is doped polysilicon or silicided polysilicon.
At this stage in the fabrication, (Step E' of FIG. 8) a buffer material may deposited to prevent the undesired etching of the lower-lying portions of the focus electrode material layer 19 during the chemical mechanical polishing (CMP) step (Step F of FIG. 8) which follows. It should be emphasized that the deposition of a buffering layer is an optional step. A suitable buffering material is a thin layer of Si 3 N 4 . The nitride buffer layer has the effect of enhancing the strength of the tip 13, which is one advantage of performing this optional step. The buffering layer substantially impedes the progress of the CMP into the layer on which the buffering material is deposited.
The next step in the gate formation process (STEP F of FIG. 8) is the chemical mechanical planarization (CMP), also referred to in the art as chemical mechanical polishing (CMP). Through the use of chemical and abrasive techniques, the buffer material as well as any other layers (e.g. the peaks of the focus electrode layer, the conformal insulating layers and the conductive gate layer) extending beyond the emitter tip 13 are "polished" away.
In general, CMP involves holding or rotating a wafer of semiconductor material against a wetted polishing surface under controlled chemical slurry, pressure, and temperature conditions. A chemical slurry containing a polishing agent such as alumina or silica may be utilized as the abrasive medium. Additionally, the chemical slurry may contain chemical etchants. This procedure may be used to produce a surface with a desired endpoint or thickness, which also has a polished and planarized surface. Such apparatus for polishing are disclosed in U.S. Pat. Nos. 4,193,226 and 4,811,522. Another such apparatus is manufactured by Westech Engineering and is designated as a Model 372 Polisher.
CMP will be performed substantially over the entire wafer surface, and at a high pressure. Initially, CMP will proceed at a very fast rate, as the peaks are being removed, then the rate will slow dramatically after the peaks have been substantially removed. The removal rate of the CMP is proportionally related to the pressure and the hardness of the surface being planarized.
FIG. 4 illustrates the intermediate step in the gate formation process following the chemical mechanical planarization CMP. A substantially planar surface is achieved, and the second conformal insulating layer 14 is thereby exposed. At this point, (Step G of FIG. 8) the various layers can be selectively etched to expose the emitter tip 13 and define the self-aligned gate 15 and focus ring 19 structures using any of the various etching techniques known in the art. As a result of the CMP process, the order of layer removal can also be varied.
In the preferred embodiment, the second insulating layer 14 is selectively etched to expose the gate. FIG. 5 shows the means by which the second conformal insulating layer 14 defines the gate 15 to focus ring 19 spacing, as well as the means by which the gate 15 and the focus rings 19 become self-aligned.
The gate material layer 15 is then etched, as shown in FIG. 6. After the gate material layer 15 is removed, the first conformal insulating layer 18 which covers the emitter tip 13 is exposed.
The next process step is a wet etching of the first selectively etchable insulating layer 18 to expose the emitter tip 13. FIG. 7 illustrates the field emitter device after the insulating cavity has been so etched.
In an alternative embodiment, (not shown) the gate material layer 15 can be removed first, thereby exposing the first insulating layer 18. Both of the selectively etchable insulating layers can then be removed at the same time, thereby exposing the emitter tip 13.
If desired, the cathode tip 13 may optionally be coated with a low work function material (Step G' of FIG. 8). Low work function materials include, but are not limited to cermet (Cr 3 Si+SiO 2 ), cesium, rubidium, tantalum nitride, barium, chromium silicide, titanium carbide, molybdenum, and niobium. Coating of the emitter tips may be accomplished in one of many ways. The low work function material or its precursor may be deposited through sputtering or other suitable means on the tip 13. Certain metals (e.g., titanium or chromium) may be reacted with the silicon of the tip to form silicide during a rapid thermal processing (RTP) step. Following the RTP step, any unreacted metal is removed from the tip 13. In a nitrogen ambient, deposited tantalum may be converted during RTP to tantalum nitride, a material having a particularly low work function. The coating process variations are almost endless. This results in an emitter tip 13 that may not only be sharper than a plain silicon tip, but that also has greater resistance to erosion and a lower work function. The silicide is formed by the reaction of the refractory metal with the underlying polysilicon by an anneal step.
It is believed obvious to one skilled in the art that the manufacturing method described above is capable of considerable variation. For example, it is possible to fabricate several focus ring structures by adding successive insulating layers 14, 14a, etc., and conductive layers 19, 19a, etc. prior to the CMP step, (the relative level of the planarization step being indicated by the dotted line) and thereafter selectively etching the layers to expose the emitter tips 13, as shown in FIGS. 3A and 7A.
All of the U.S. patents cited herein are hereby incorporated by reference herein as if set forth in their entirety.
While the particular process as herein shown and disclosed in detail is fully capable of obtaining the objects and advantages herein before stated, it is to be understood that it is merely illustrative of the presently understood embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.
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A selective etching and chemical mechanical planarization process for the formation of self-aligned gate and focus ring structures surrounding an electron emission tip for use in field emission displays in which the emission tip is i) optionally sharpened through oxidation, ii) deposited with a first conformal layer, iii) deposited with a conductive material layer, iv) deposited with a second conformal insulating layer, v) deposited with a focus electrode ring material layer, vi) optionally deposited with a buffering material, vii) planarized with a chemical mechanical planarization (CMP) step, to expose a portion of the second conformal layer, viii) etched to form a self-aligned gate and focus ring, and thereby expose the emitter tip, afterwhich xi) the emitter tip may be coated with a low work function material.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to co-pending and commonly-assigned patent application Ser. No. 09/494,325, filed on Jan. 28, 2000, by Cynthia M. Saracco, entitled “TECHNIQUE FOR DETECTING A SHARED TEMPORAL RELATIONSHIP OF VALID TIME DATA IN A RELATIONAL DATABASE MANAGEMENT SYSTEM,” which application is incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to relational database management systems, and, in particular, to a technique for detecting a subsuming temporal relationship of valid time data in a relational database management system.
2. Description of Related Art
Databases are computerized information storage and retrieval systems. A Relational Database Management System (RDBMS) is a database management system (DBMS) which uses relational techniques for storing and retrieving data. Relational databases are organized into tables which consist of rows and columns of data. The rows are formally called tuples. A database will typically have many tables and each table will typically have multiple tuples and multiple columns. The tables are typically stored on random access storage devices (RASD) such as magnetic or optical disk drives for semi-permanent storage.
RDBMS software using a Structured Query Language (SQL) interface is well known in the art. The SQL interface has evolved into a standard language for RDBMS software and has been adopted as such by both the American National Standards Institute (ANSI) and the International Standards Organization (ISO). The SQL interface allows users to formulate relational operations on the tables either interactively, in batch files, or embedded in host languages, such as C and COBOL. SQL allows the user to manipulate the data.
A data warehouse is a combination of many different databases across an entire enterprise. Data warehouses contain a wide variety of data that presents a coherent picture of business conditions at a single point in time. As a result, many companies use data warehouses to support management decision making. A data mart is similar to a data warehouse. The only difference between the data mart and the data warehouse is that data marts are usually smaller than data warehouses, and data marts focus on a particular subject or departments. Both the data warehouse and the data mart use the RDBMS for storing and retrieving information.
Companies frequently use data warehouses and data marts to create billions of bytes of data about all aspects of a company, including facts about their customers, products, operations, and personal. Many companies use this data to evaluate their past performance and to plan for the future. To assist the companies in analyzing this data, some data warehousing and decision support professionals write applications and generate reports that seek to shed light on a company's recent business history.
Several common forms of data analysis involve evaluating time-related data, such as examining customer buying behaviors, assessing the effectiveness of marketing campaigns or determining the impact of organizational changes on sales during a selected time period. The relevance of time-related data to a variety of business applications has caused some DBMS professionals to reexamine the need for temporal data analysis.
Temporal data is often used to track the period of time at which certain business conditions are valid. To illustrate, a company may sell product X for: $50 during a first period of time; $45 during a second period of time; and $52 during a third period of time. The company may even know that this same product will sell for $54 during some future period of time. When the company's database contains information about the valid times for each of these price points, the pricing points are referred to as temporal data. Common techniques for recording valid time information in a RDBMS involve including a DATE column in a table that tracks business conditions, such as a START_DATE and an END_DATE column in a table that tracks pricing information for products.
Analyzing temporal data involves understanding the manner in which different business conditions relate to one another over time. Returning to the previous example, each product has a retail price for a given period of time, and each product also has a wholesale cost. Retail prices can fluctuate independently of the product's wholesale cost, and vice versa. To determine efficiencies (or inefficiencies) in a product's pricing scheme, a retailer may wish to understand the relationship between a product's retail price and a product's wholesale cost over time. More specifically, a retailer may wish to evaluate: whether products are being placed on sale at inopportune times (e.g., before the retailer is eligible to receive a reduction in wholesale price) or whether the retailer has failed to pass on cost savings to customers (e.g., failing to place products on sale during the period in which their wholesale cost is reduced).
These questions involve temporal analysis because the questions involve tracking the period of time at which certain business conditions were in effect. These questions can be challenging to express in SQL, and many users are incapable of correctly formatting such SQL queries. Further, mistakes in the SQL query are common and difficult to detect.
Thus, there is a need in the art for a technique of creating a simplified SQL query to analyze the temporal relationships of various business conditions.
SUMMARY OF THE INVENTION
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a method, apparatus, and article of manufacture for detecting subsuming temporal relationships in a relational database.
In accordance with the present invention, an invocation of a within operation that specifies a first event and a second event is received. In response to the invocation, a combination of temporal relationships between the first event and the second event is evaluated to determine (1) whether the second event starts at the same time as the first event or whether the second event starts before the first event and (2) whether the second event ends at the same time as the first event or whether the second event ends after the first event.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings in which like reference numbers represent corresponding parts throughout:
FIG. 1 schematically illustrates a hardware environment of a preferred embodiment of the present invention;
FIG. 2 illustrates seven temporal relationship operators; and
FIGS. 3A-3B are flow charts that illustrate the steps performed by the single function operator system in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof, and which is shown by way of illustration a specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized as structural changes may be made without departing from the scope of the present invention.
Hardware Environment
FIG. 1 illustrates a computer hardware environment that could be used in accordance with the present invention. In the exemplary environment, a computer system 102 is comprised of one or more processors connected to one or more data storage devices 104 and 106 that store one or more relational databases, such as a fixed or hard disk drive, a floppy disk drive, a CDROM drive, a tape drive, or other device.
Operators of the computer system 102 use a standard operator interface 108 , such as IMS/DB/DC®, CICS®, TSO®, OS/390®, ODBC® or other similar interface, to transmit electrical signals to and from the computer system 102 that represent commands for performing various search and retrieval functions, termed queries, against the databases. In the present invention, these queries conform to the Structured Query Language (SQL) standard, and invoke functions performed by Relational DataBase Management System (RDBMS) software.
The SQL interface has evolved into a standard language for RDBMS software and has been adopted as such by both the American National Standards Institute (ANSI) and the International Standards Organization (ISO). The SQL interface allows users to formulate relational operations on the tables either interactively, in batch files, or embedded in host languages, such as C and COBOL. SQL allows the user to manipulate the data.
In the preferred embodiment of the present invention, the RDBMS software comprises the DB2® UDB V5.2 product offered by IBM for the Windows NT 4.0 operating systems. Those skilled in the art will recognize, however, that the present invention has application program to any RDBMS software, whether or not the RDBMS software uses SQL.
As illustrated in FIG. 1, the DB2® UDB V5.2 system for the Windows NT 4.0 operating system includes three major components: the Internal Resource Lock Manager (IRLM) 110 , the Systems Services module 112 , and the Database Services module 114 . The IRLM 110 handles locking services for the DB2® UDB V5.2 system, which treats data as a shared resource, thereby allowing any number of users to access the same data simultaneously. Thus concurrency control is required to isolate users and to maintain data integrity. The Systems Services module 112 controls the overall DB2® UDB V5.2 execution environment, including managing log data sets 106 , gathering statistics, handling startup and shutdown, and providing management support.
At the center of the DB2® UDB V5.2 system is the Database Services module 114 . The Database Services module 114 contains several submodules, including the Relational Database System (RDS) 116 , the Data Manager 118 , the Buffer Manager 120 , the Rebalancing System 124 , and other components 122 such as an SQL compiler/interpreter. These submodules support the functions of the SQL language, i.e. definition, access control, interpretation, compilation, database retrieval, and update of user and system data. The Single Function Operator System 124 works in conjunction with the other submodules to provide a single function operator that simplifies the process of detecting and tracking subsuming temporal relationships.
The present invention is generally implemented using SQL statements executed under the control of the Database Services module 114 . The Database Services module 114 retrieves or receives the SQL statements, wherein the SQL statements are generally stored in a text file on the data storage devices 104 and 106 or are interactively entered into the computer system 102 by an operator sitting at a monitor 126 via operator interface 108 . The Database Services module 114 then derives or synthesizes instructions from the SQL statements for execution by the computer system 102 .
Generally, the RDBMS software, the SQL statements, and the instructions derived therefrom, are all tangibly embodied in a computer-readable medium, e.g. one or more of the data storage devices 104 and 106 . Moreover, the RDBMS software, the SQL statements, and the instructions derived therefrom, are all comprised of instructions which, when read and executed by the computer system 102 , causes the computer system 102 to perform the steps necessary to implement and/or use the present invention. Under control of an operating system, the RDBMS software, the SQL statements, and the instructions derived therefrom, may be loaded from the data storage devices 104 and 106 into a memory of the computer system 102 for use during actual operations.
Thus, the present invention may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques to produce software, firmware, hardware, or any combination thereof. The term “article of manufacture” (or alternatively, “computer program product”) as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. Of course, those skilled in the art will recognize many modifications may be made to this configuration without departing from the scope of the present invention.
Those skilled in the art will recognize that the exemplary environment illustrated in FIG. 1 is not intended to limit the present invention. Indeed, those skilled in the art will recognize that other alternative hardware environments may be used without departing from the scope of the present invention.
Single Function Operator System
The growing interest in advanced data analysis techniques—prompted, in part, by increased use of data warehouses, data marts, and other decision support environments—has led some DBMS professionals to revisit the need for temporal data analysis. Such analysis attempts to discern the manner in which the states of things (e.g., product content, product pricing, product promotions, product management, etc.) vary over time and the manner in which these different states may be inter-related.
For example, a product may sell at its standard retail price for certain periods of time, while at other times it may sell at various discounted rates. Furthermore, this same product may cost the retailer different prices at different periods of time (perhaps due to a manufacturer's rebate offer). Understanding the relationship between the product's various states of pricing can be important when determining the effectiveness of the product's pricing strategy and assessing profits on the product's sales.
The examples discussed herein involve retail-oriented databases with a star schema architecture. The retail industry is used because of its commercial significance in the data warehousing and decision support fields and because members of the retail industry tend to be interested in temporal analysis. However, the single function operator system 124 is applicable to other industries.
Some forms of temporal analysis are challenging to express using current commercial technology. Researchers have argued that these commercial limitations may place an undue burden on DBMS users in the future, as data warehouses are likely to store greater quantities of historical data.
Temporal data tracks state-related information. This often translates into recording the time period for which a given condition was (or is or will be) valid. An example of temporal data is shown below in Table 1 and Table 2. Specifically, Table 1 and Table 2 contain information about Grace Theophila's salary and job titles over time. Grace Theophila is a fictional employee. Date information is shown in the MM/DD/YYYY format.
TABLE 1
ID
NAME
SALARY
START_DATE
END_DATE
123
Grace Theophila
45,000
Feb. 01, 1997
Apr. 20, 1998
123
Grace Theophila
48,000
Apr. 20, 1998
Oct. 30, 1998
123
Grace Theophila
49,500
Oct. 30, 1998
Apr. 04, 1999
...
...
...
...
...
TABLE 2
START —
ID
NAME
TITLE
DATE
END_DATE
123
Grace Theophila
Asst
Feb. 01, 1997
Dec. 01, 1997
Manager
123
Grace Theophila
Manager
Feb. 01, 1997
Apr. 04, 1999
...
...
...
...
...
Both Table 1 and Table 2 track valid time information about different business conditions. Table 1 records salary information for employees throughout various periods of time, and Table 2 records employees'job titles throughout various periods of time. The “period” nature is a characteristic of temporal data and temporal analysis.
Traditional databases (i.e., databases which focus on currently valid data) rarely model employee salary and job title information in two separate tables, as shown in Table 1 and Table 2. However, for simplicity, a “temporal” database (i.e., one which attempts to track historical information and, possibly, current and future information as well) may model data in separate tables. An employee's salaries and job titles can vary over time, independently of one another. Storing both pieces of information in a single temporal table forces the DBMS professional to design the database in the following manner either: (1) retain only one start/end date pair to record the valid time for all the row's content; or (2) include multiple start/end date pairs, each recording the valid time for a single part of the row's content. Each of these design options increases the complexity of the temporal analysis. Therefore, in the interest of simplicity and clarity, the single function operator system 124 will be described herein with respect to separate tables for each type of data. However, if desired, the single function operator system 124 can be used with other database designs, e.g., single table designs.
Both Table 1 and Table 2 use dates as their level of temporal granularity, because presumably, an employee's salary or job title remains constant for a single day. However, temporal data can be recorded at coarser or finer levels of granularity. The START_DATE represents the first day on which the condition became true, and the END_DATE represents the first day thereafter in which the condition failed to remain true. For example, beginning Feb. 1, 1997, Grace had a salary of $45,000 per year. Grace continued to earn this salary until—but not including—Apr. 20, 1998. This technique of modeling temporal data is sometimes referred to as a “closed-open” representation in research literature. Of course, other representations of the data are possible without exceeding the scope of the single function operator system 124 .
Many of the underlying principles for a preferred embodiment of the single function operator system 124 are based on the theoretical work of J. F. Allen, who identified a set of operators (commonly referred to as Allen's operators) that can be used to assess temporal relationships. Allen's operators can be expressed in a variety of languages, including SQL.
Allen's operators are shown in FIG. 2 . FIG. 2 has an OPERATOR column 200 , a RELATIONSHIP column 202 , and a GRAPHIC EXAMPLE column 204 . The OPERATOR column 200 contains seven of Allen's operators, including BEFORE 206 , MEETS 208 , OVERLAPS 210 , DURING 212 , STARTS 214 , FINISHES 216 , and EQUAL 218 . These operators 206 , 208 , 210 , 212 , 214 , 216 , and 218 perform a comparison operation. The result of each comparison operation yields a TRUE or FALSE value. The RELATIONSHIP column 202 shows the relationship between a time period X 220 and a time period Y 222 . The GRAPHIC EXAMPLE column 204 displays a graphical representation of the relationship between the time period X 220 and the time period Y 222 . Other of Allen's operators include MET BY, OVERLAPPED BY, STARTED BY, and FINISHED BY. The results of these operators also produce a TRUE or FALSE value.
The preferred embodiment of the single function operator system 124 combines some of the operators 206 , 208 , 210 , 212 , 214 , 216 , and 218 into a single function. Combining some of the operators 206 , 208 , 210 , 212 , 214 , 216 , and 218 simplifies certain queries and helps reduce the number of lines of SQL code. More specifically, an embodiment of the single function operator system 124 provides a WITHIN operator that combines the EQUAL 218 , DURING 212 , STARTS 214 , and FINISHES 216 operators into a single function operator. The WITHIN operator returns a TRUE value when the time period X 220 is wholly or partly contained (or subsumed) within the time period Y 222 .
Another embodiment of the present invention provides a SHARES operator. The SHARES operator is similar to the WITHIN operator. Like the WITHIN operator, the SHARES operator combines the EQUAL 218 , DURING 212 , STARTS 214 , and FINISHES 216 operators into a single function operator. The difference between the WITHIN operator and the SHARES operator is that the SHARES operator adds the following operators to the combination: OVERLAPS 210 , OVERLAPPED BY, CONTAINS, STARTED BY, and FINISHED BY. The SHARES operator returns a TRUE value when time period X 220 shares any time in common with time period Y 222 .
To illustrate the benefits of the SHARES operator, the SHARES operator is used to extract data from Table 3 and Table 4 . Table 3 represents a Store database. The Store database records data about stores and the districts to which each store reports. Table 3 contains five columns, a SID column, a STORE_NAME column, a DID column, a ORG_START column, and ORG_END column.
The SID column contains a store identifier. The STORE_NAME column contains the name of store. The DID column contains the district identifier of the district that the store reports to. The ORG_START column contains the start date of the store-to-district reporting structure, and the ORG_END column contains the end date of the store-to-district reporting structure.
TABLE 3
SID
STORE_NAME
DID
ORG_START
ORG_END
0
Acme 0
7
May 06, 1998
July 20, 1998
0
Acme 0
6
Jan. 01, 1998
May 06, 1998
1
Acme 1
7
Apr. 20, 1998
May 05, 1998
2
Acme 2
6
Jan. 01, 1998
Sep. 30, 1998
2
Acme 2
7
Sep. 30, 1998
Dec. 30, 1998
3
Acme 3
5
Jan. 10, 1998
Dec. 30, 1998
4
Acme 4
5
Sep. 01, 1998
Dec. 30, 1998
...
...
...
...
...
Table 4 represents a District database. The District database records data about the districts and about the districts associated trading area. Table 4 contains five columns: a DID column that contains a district identifier; a D_NAME column that contains a district name; a TID column that contains an identifier of the trading area that the districts reports to; an ORG_START column that contains a start date of the reporting structure, and an ORG_END column that contains an end date of the reporting structure.
TABLE 4
DID
D_NAME
TID
ORG_START
ORG_END
5
Valley District
11
Jan. 01, 1998
July 30, 1998
6
Springs District
11
May 30, 1998
Dec. 30, 1998
6
Lakes District
12
Jan. 01, 1998
May 30, 1998
7
Mountain District
12
Feb. 04, 1998
Nov. 30, 1998
5
Willows District
12
July 30, 1998
Aug. 30, 1998
6
Waterfront District
9
Jan. 01, 1997
Dec. 30, 1997
...
...
...
...
...
As an example, assume that a query seeks to report the names of stores and the districts which the stores are associated with over time. This type of query is sometimes referred to as a “temporal sequenced join”. Such a query might produce a report that cites the name of each store, the name of the district into which the store reported, and the dates for which this store-to-district reporting information is valid. Table 5 represents a sample result.
TABLE 5
STORE_NAME
D_NAME
ORG_START
ORG_END
Acme 0
Lakes District
Jan. 01, 1998
May 06, 1998
Acme 0
Mountain District
May 06, 1998
July 20, 1998
Acme 1
Mountain District
Apr. 20, 1998
May 05, 1998
Acme 2
Lakes District
Jan. 01, 1998
Sep. 30, 1998
Acme 2
Springs District
Jan. 01, 1998
Sep. 30, 1998
Acme 2
Mountain District
Sep. 30, 1998
Dec. 30, 1998
Acme 3
Valley District
Jan. 10, 1998
Dec. 30, 1998
Acme 3
Willows District
Jan. 10, 1998
Dec. 30, 1998
Some conventional techniques for drafting a query that produces the results contained in Table 5 require four SELECT statements, three UNION statements, and a total of eleven data comparison operations. Each SELECT statement tests for some relationship between the time period of validity for the store-to-district reporting structure. The data comparison operators, which implement Allen's operators, test for various temporal relationships. After testing for the temporal relationships, the query then unions the results together. A sample conventional query is shown below:
SELECT store_name, d_name, store.org_start, store.org_end
FROM store, district
WHERE store.did=district.did
and district.org_start<=store.org_start
and store.org_end<=district.org_end
UNION
SELECT store_name, d_name, store.org_start, store.org_end
FROM store, district
WHERE store.did=district.did
and store.org_start>district.org_start
and district.org_end<store.org_end
and store.org_start<district.org_end
UNION
SELECT store_name, d_name, store.org_start, store.org_end
FROM store, district
WHERE store.did=district.did
and district.org_start>store.org_start
and store.org_end<district.org_end
and district.org_tart<store.org_end
UNION
SELECT store_name, d_name, store.org_start, store.org_end
FROM store, district
WHERE store.did=district.did
and district.org_start>=store.org_start
and district.org_end<=store.org_end
ORDER BY store_name
The above query contains four query blocks. Each section of the query that begins with a SELECT statement is a query block. Each query block contains a standard join clause based on the district identification number (i.e., the DID column of the STORE and DISTRICT tables). Each query block also includes a temporal join clause.
To simplify the discussion of the temporal join clauses, assume “P 1 ” denotes the time period specified by the ORG_START and ORG_END dates of the STORE table shown in Table 3, and assume “P 2 ” denotes the time period specified by the ORG_START and ORG_END dates of the DISTRICT table shown in Table 4. Thus, the four query blocks test for the following temporal conditions:
Query Block 1 : P 1 DURING P 2 or P 1 EQUAL P 2 or P 1 STARTS P 2
Query Block 2 : P 2 OVERLAPS P 1
Query Block 3 : P 1 OVERLAPS P 2
Query Block 4 : P 2 DURING P 1 or P 2 EQUAL P 1 or P 2 FINISHES P 1
While this query produces the intended result set shown in Table 5, many users would experience difficulty formulating this query. In particular, few users are capable of developing the logic and correctly coding the syntax (particularly all the date comparison operators) in a timely manner. Assuming that users store their temporal data in a relational or object/relational DBMS, a user must perform the following steps to formulate the above query: (1) understand the logic of each of the relevant temporal conditions; (2) correctly translate the logic into SQL date comparison operators; (3) formulate appropriate query blocks; and (4) UNION these query blocks together. Such query logic can be difficult to debug, as an error in one date comparison operator will yield incorrect results. However, that same error will fail to produce an error warning message from the database. In addition to the difficulty in formulating and debugging the SQL query, the execution of the SQL query can cause a database management system to scan the table(s) referenced in the query multiple time (one time for each query block). Such scanning may result in considerable input and output processing and poor performance (e.g., delays in receiving query results).
Fortunately, the single function operator system 124 provides the SHARES operator. The SHARES operator simplifies the above query. More specifically, the SHARES operator eliminates three of the four SELECT statements, all of the UNION statements, and ten of the eleven date comparisons. Using the SHARES operator, the above query can be revised as follows:
SELECT store_name, store.did, d_name, store.org_start, store.org_end
FROM store, district
WHERE store.did=district.did
and shares(store.org_start, store.org_end, district.org_start,
district.org_end)=1
ORDER BY store_name, store.did
In addition to greatly simplifying the traditional query, the revised query adds a the district identifier (the DID column of Table 4) to the result shown in Table 6.
TABLE 6
STORE —
NAME
DID
D_NAME
ORG_START
ORG_END
Acme 0
6
Lakes District
Jan. 01, 1998
May 05, 1998
Acme 0
7
Mountain District
May 06, 1998
July 20, 1998
Acme 1
7
Mountain District
Apr. 20, 1998
May 05, 1998
Acme 2
6
Springs District
Jan. 01, 1998
Sep. 30, 1998
Acme 2
6
Lakes District
Jan. 01, 1998
Sep. 30, 1998
Acme 2
7
Mountain District
Sep. 30, 1998
Dec. 30, 1998
Acme 3
5
Valley District
Jan. 10, 1998
Dec. 30, 1998
Acme 3
5
Willows District
Jan. 10, 1998
Dec. 30, 1998
In the revised query, the operator that eliminates the most code is the SHARES OPERATOR:
shares(store.org_start, store.org_end, district.org_start, district.org_end)=1
The SHARES function combines several temporal tests into one. A temporal relationship exists when either time period is equal to the other time period, or overlaps with the other time period, or occurred during the other time period, or starts during the other time period, or finishes during the other time period. That is, the two periods share some time in common.
The SHARES operator expects to receive four DATE values as input (each pair containing the start/end points of each time period). The SHARES operator returns a “1” if the test evaluates as TRUE or a “0” if the test evaluates as FALSE.
The WITHIN operator also eliminates the amount of code used in a traditional query. To illustrate the benefit of using the WITHIN operator, the WITHIN operator is used to extract data from Table 7 and Table 8 below.
Table 7 represents a Discount database. The discount database records the retail price discount offered by store for products. Table 7 contains five columns: a PID column, a SID column, a PERCENT_OFF column, a D_START column, and a D_END column. The PID column contains a product identifier. The SID column contains a store identifier. The PERCENT_OFF column contains a discount rate. The D_START column contains a start time for a discount on product. The D_END columns contains the end time for a discount on product.
TABLE 7
PID
SID
PERCENT_OFF
D_START
D_END
100
3
5
May 01, 1998
May 30, 1998
200
1
7
Apr. 30, 1998
May 10, 1998
200
2
7
Apr. 30, 1998
May 10, 1998
600
2
5
Nov. 30, 1998
Dec. 05, 1998
500
0
10
Feb. 01, 1998
Feb. 10, 1998
...
...
...
...
...
Table 8 represents a Manu_Special database. The Manu_Special database records a manufacturer's discount offered to retailers. Table 8 contains four columns, a PID column, a PERCENT_OFF column, a S_START column, and a S_END column. The PID column contains the product identifier. The PERCENT_OFF column contains manufacturer's discount rate. The S_START column contains the start date of manufacturer's special pricing. The S_END column contains the end date of manufacturer's special pricing.
TABLE 8
PID
PERCENT_OFF
S_START
S_END
100
2
Apr. 30, 1998
May 15, 1998
100
5
July 30, 1998
Aug. 15, 1998
400
10
July 30, 1998
Aug. 30, 1998
600
5
Dec. 10, 1998
Dec. 30, 1998
500
15
Jan. 01, 1998
Feb. 15, 1998
...
...
...
...
A sample query is shown below. The query seeks to determine which products were put on sale during a time period X 220 , wherein the time period X 220 occurs outside of the time period Y 222 . The time period Y 222 represents the time period in which the store was eligible to receive a manufacturer's rebate. In other words, the query seeks to determine if any portion of a product's retail discount period fell outside the manufacturer's rebate period.
SELECT discount.pid, sid, d_start as disc_start,
d_end as disc_end,
s_start as rebate_start,
s_end as rebate_end
FROM discount, manu_special
WHERE discount.pid=manu_special.pid
and ((d_start<s_start) or (d_end>s_end))
The query contains one query block. The query block contains a standard join clause based on the product identification number (i.e., the PID column of the Discount and Manu_Special tables). The query block also includes a temporal join clause. Formulating this temporal join clause is difficult because correct date comparison operations must be specified. In this example, the goal is to produce a result that contains discounted products that fell outside the manufacturer's rebate period—that is, any discounts occurring before or after the rebate period. To simplify the discussion of the temporal join clauses, assume “P 1 ” denotes the time period specified by the D_START and D_END dates of the Discount table shown in Table 7, and assume “P 2 ” denotes the time period specified by the S_START and S_END dates of the Manu Special table shown in Table 8.
While this query produces the intended result set, many people would experience difficulty formulating this query. In particular, few people are capable of developing the logic and correctly coding the syntax (particularly the date comparison operators) in a timely manner. The WITHIN operator simplifies the above query. Using the WITHIN operator, the above query can be revised as follows:
SELECT discount.pid, sid, d_start as disc_start,
d_end as disc_end,
s_start as rebate_start,
s_end as rebate_end
FROM discount, manu_special
WHERE discount.pid=manu_ 1 special.pid
and within(d_start, d_end, s_start, s_end)=0
In the revised query, formulating the temporal portion of the query is simple. Namely, the revised query returns those rows that lack the WITHIN condition. Specifying that the query return a “0” or FALSE value produces rows that lack the WITHIN condition.
FIGS. 3A and 3B are flow charts illustrating the steps performed by the present invention 124 in accordance with an embodiment of the single function operator system 124 . In particular FIG. 3A illustrates the steps performed by the present invention to create a WITHIN operator and FIG. 3B illustrates the steps performed by the present invention to create a SHARES operator.
In FIG. 3A, block 300 represents the single function operator system 124 receiving a WITHIN operator. Block 302 represents the single function operator system 124 logically combining the EQUAL, DURING, STARTS, and FINISHES operators into a single function operation represented by the WITHIN operator.
In FIG. 3B, block 304 represents the single function operator system receiving a SHARES operator. Block 306 represents the single function operator system 124 logically combining the OVERLAP, OVERLAPPED BY, DURING, CONTAINS, STARTS, STARTED BY, FINISHES, FINISHED BY, and EQUALS operators into a single operation represented by the SHARES operator.
CONCLUSION
This concludes the description of the preferred embodiment of the invention. The following describes some alternative embodiments for accomplishing the present invention. For example, any type of computer, such as a mainframe, minicomputer, or personal computer, or computer configuration, such as a timesharing mainframe, local area network, or standalone personal computer, could be used with the present invention.
The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
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A method, apparatus, and article of manufacture for detecting subsuming temporal relationships in a relational database. In accordance with the present invention, an invocation of a within operation that specifies a first event and a second event is received. In response to the invocation, a combination of temporal relationships between the first event and the second event is evaluated to determine (1) whether the second event starts at the same time as the first event or whether the second event starts before the first event and (2) whether the second event ends at the same time as the first event or whether the second event ends after the first event.
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FIELD OF THE INVENTION
[0001] The present invention relates to amplifier circuits generally and, more particularly, to a method and/or apparatus for implementing a low-voltage constant-gm rail-to-rail CMOS input stage with improved gain.
BACKGROUND OF THE INVENTION
[0002] Conventional amplifier circuits often implement operational amplifiers. Supply voltages tend to decrease as process technology scales down. In low voltage applications, signal levels remain the same to obtain a targeted signal-to-noise ratio. Conventional input differential transistor pairs cannot satisfy stringent signal-to-noise specifications. Conventional approaches suffer from drawbacks such as low DC gain when input common mode is close to ground.
[0003] It would be desirable to implement a low-voltage constant-gm rail-to-rail CMOS stage with improved gain. It would also be desirable to implement a low voltage constant-gm rail-to-rail CMOS input stage that may be used in analog and/or mixed signal applications.
SUMMARY OF THE INVENTION
[0004] The present invention concerns an apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate an output signal in response to a differential input signal, a first power supply and a ground. The output signal may have a rail-to-rail voltage with a magnitude between the first power supply and the ground. The first circuit may also be configured to source an intermediate differential signal in response to the differential input signal, the first power supply and ground. The second circuit may be configured to sink the differential intermediate signal in response to the differential input signal, the first power supply, ground and a second power supply. The second circuit may flatten the transconductance of the first circuit relative to a common mode voltage of the differential input signal.
[0005] The objects, features and advantages of the present invention include providing an amplifier stage that may (i) provide an improvement in gain, (ii) reduce variations in gain, (iii) reduce harmonic distortion with higher gain, (iv) be implemented without additional design specifications and/or extra gain stages, (v) provide a low-voltage constant-gm rail-to-rail CMOS input stage with improved gain, and/or (vi) overcome DC gain issues.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] These and other objects, features and advantages of the present invention will be apparent from the following detailed description and the appended claims and drawings in which:
[0007] FIG. 1 is a block diagram of the present invention;
[0008] FIG. 2 is a more detailed diagram of the present invention;
[0009] FIG. 3 is a plot of the comparison of transconductance versus input common mode voltage;
[0010] FIG. 4 is a plot of a comparison of gain variation versus input common mode;
[0011] FIG. 5 is a conceptual diagram of an N-type differential input stage;
[0012] FIG. 6 is a conceptual diagram of a P-type differential input stage;
[0013] FIG. 7 is a conceptual diagram of the current flow when an input voltage level is close to ground; and
[0014] FIG. 8 is a conceptual diagram when an input voltage level is close to mid level and/or close to a supply level.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Referring to FIG. 1 , a block diagram of a circuit 100 is shown in accordance with an embodiment of the present invention. The circuit 100 generally comprises a block (or circuit) 102 and a block (or circuit) 104 . The circuit 102 may provide a low voltage constant-gm rail-to-rail CMOS input stage that may be used in analog and/or mixed signal applications. The circuit 104 may be implemented as a compensation circuit. The circuit 100 may improve the gain of an input stage across a rail-to rail input common mode. The circuit 100 may also provide a higher gain and/or may improve harmonic distortion of an operational-amplifier. The circuit 100 may incorporate a general purpose low-voltage constant-gm rail-to-rail input stage 102 that may provide a solution to improve the gain across rail-to-rail input common mode. The circuit 100 may provide a gain enhancement.
[0016] The circuit 102 may receive a signal (e.g., VDDA), a signal (e.g., VI+), a signal (e.g., VI−), and a signal (e.g., VSSA). The circuit 102 may present a current (e.g., IA), a current (e.g., IB), a signal (e.g., V 0 ), and a signal (e.g., V 0 B). The circuit 104 may receive the signal VDDA, a signal (e.g., VDDA/2), the signal VI+, the signal VI−, the current LA, the current IB and the signal VSSA. The signal VDDA may be a supply voltage. The signal VDDA/2 may have a magnitude around one half of the supply voltage VDDA. The signal VSSA may be ground voltage.
[0017] Referring to FIG. 2 , a more detailed diagram of the circuit 100 is shown. The circuit 100 may overcome limitations on the input common mode voltage VCMR that may commonly be associated with a typical n-channel or p-channel differential input stage. The signal VI (e.g., either VI+ or VI−) may be presented to the input terminal of each amplifier stage. The signal VI may have a voltage range when a particular amplifier becomes operation. The voltage range of the signal VI may be referred to as a voltage common mode range (VCMR). The signals VI+/VI− may represent a positive/negative terminal of each amplifier stage. Two floating voltage sources (e.g., VI++/VI−−) may be implemented by two similar source followers (e.g., S 1 -S 2 and/or S 3 -S 4 ) connected in front of the input terminals of one of the differential pairs ( 1 NS- 2 NS). The source followers S 1 -S 2 and/or S 3 -S 4 may provide a positive voltage shift on the signal VGS to the signal VCMR applied to the differential pair 1 NS- 2 NS. To ensure rail-to-rail operation, the voltage shift from the signal VCMR should normally keep the corresponding input pair active when the other differential pair (e.g., 1 N- 2 N) is inactive (e.g., when the signal VCMR is close to ground).
[0018] The circuit 102 generally comprises a section 110 , a section 112 , a section 114 , a section 115 , a section 116 , a section 118 , and a section 120 . The section 112 may include a transistor A 1 S and a transistor A 2 S. The section 112 may be active when a common mode is at a mid level. The section 114 may include a transistor S 1 and a transistor S 2 . The section 115 may include a transistor 1 N and a transistor 2 N. The transistor pair 1 N and 2 N may be active when an input mode is close to a level of the signal VDDA. The section 115 may also include the transistor 1 NS and the transistor 2 NS. The transistor 1 NS and 2 NS may be active when a common mode is close to a level of the signal SSA. The section 120 may include a transistor S 3 and a transistor S 4 .
[0019] The transistor S 1 and a transistor S 2 may be implemented as PMOS transistors. Similarly, the transistor S 3 and the transistor S 4 may be implemented as PMOS transistors. The transistor pair S 1 and S 2 and the transistor pair S 3 and S 4 may be implemented as level shifters configured to shift an input level when the circuit 100 is active.
[0020] For levels of the signal VCMR close to ground, the current source transistors (e.g., BA and BN) and hence, the transistor pairs A 1 -A 2 and 1 N- 2 N, are normally cut-off. Then, the small- and large-signal behaviors of the rail-to-rail input stage result only by the contribution of the differential pair 1 NS- 2 NS, which is biased with current equal to the current IC (the ensuing transconductance will be referred to as g m0 ). In the middle voltage range, both input pairs ( 1 N- 2 N and 1 NS- 2 NS) are active. However, a bias current equal to the current IC is provided to an input pair A 1 S-A 2 S, which cancels out the limiting current and transconductance contribution of one of the differential pairs of the input stage. Finally, for values of the signal VCMR close to the supply VDDA, the bias current IBS of the input level shifters becomes zero and, consequently, the input pairs A 1 S-A 2 S and 1 NS- 2 NS provide no contribution to the output. Thus, the only differential pair active is 1 N- 2 N, and the small and large signal behaviors of the stage are the same as in the above considered operating regions. The following TABLE 1 shows the current flowing in each of the differential pairs and through the load devices M 5 /M 6 when the circuit 104 is not present:
[0000]
TABLE 1
Current conducting
Diff Pairs
Current through
VCMR Range
1N-2N
1NS-2NS
A1S-A2S
M5/M6(I L )
Close to Ground
0
I C /2
0
I B -I C /2
(VSSA)
Mid-level
I C /2
I C /2
I C /2
I B -3I C /2
Close to Supply
I C /2
I C /2
I C /2
I B -3I C /2
(VDDA)
[0021] Open loop gain of the amplifier in FIG. 2 ,
[0000] Av≈g m0 [g m4 r 04 r 02 ∥g m6 r 06 r 08 ]
[0000] Where, g mx and r 0x are the transconductance and output impedance of transistor MX in FIG. 2 respectively.
[0022] For simplicity assume,
[0000] g m4 ≈g m6
[0000] r 04 ≈r 06
[0000] r 02 ≈r 08
[0000] Therefore,
[0000] Av≈g m0 [g m4 r 04 r 02 ]/2
[0000] Across rail-to-rail g m0 is nearly constant, therefore,
[0000] Avαg m0 [g m4 r 04 r 02 ]/2
[0000] g m4 α√I L
[0000] r 04 ,r 02 α1/I L
[0000] Therefore, Avα√I L ×1/I L ×1/I L
[0000] AvαI L −3/2
[0000] ΔAvα(ΔI L ) −3/2 [when g m0 is constant]
[0023] Therefore, when transconductance of the input stage 102 is constant, the current through the transistors M 5 /M 6 should also remain constant across rail-to-rail in order to have a constant gain Av.
[0024] When the signal VCMR is close to the ground voltage VSSA, the transistors D 1 /D 2 are cut-off and no current flows through the transistor MD 3 . All of the current IC flows through the transistor MD 5 and the current IC flows through each node A/B. This compensates for the cut-off of the transistors 1 N/ 2 N and the transistors A 1 S/A 2 S. As a result, the current IL is maintained as I L =I B −3I C /2 when the signal VCMR is close to ground.
[0025] When the signal VCMR is in the middle voltage or close to VDDA range then D 1 /D 2 are active and I C flows through MD 3 and no current flows D 5 /D 6 /D 7 /D 8 . As a result no current flows through A/B and, consequently, I L =I B −3I C /2 is maintained at this input common mode range. The following TABLE 2 shows the current flowing in each differential pair and through the load devices M 5 /M 6 .
[0000]
TABLE 2
Current conducting
Diff Pairs
Current through
VCMR Range
1N-2N
1NS-2NS
A1S-A2S
M5/M6(I L )
Close to Ground
I C /2
I C /2
I C /2
I B -3I C /2
(VSSA)
Mid-level
I C /2
I C /2
I C /2
I B -3I C /2
Close to Supply
I C /2
I C /2
I C /2
I B -3I C /2
(VDDA)
[0026] Referring to FIG. 3 , a plot illustrating a comparison of the gm with respect to the signal VCMR in the case of the circuit 100 versus a conventional circuit is shown. FIG. 3 shows the variation of transconductance GM with respect to the signal VCMR as being nearly the same.
[0027] Referring to FIG. 4 , a plot illustrating a comparison of DC gain with respect to the signal VCMR of the circuit 100 versus a conventional circuit. An example of minimum gain shown is 40 dB. The variation of gain of 40-45 dB illustrates an improvement from the gain of 28-43 dB without the circuit 104 .
[0028] Referring to FIG. 5 , a diagram illustrating an example of an N-type differential input stage used in the circuit 100 is shown. A voltage VCMR may be equal to VDDA−Vgs(MN)−Vdsat(IB).
[0029] Referring to FIG. 6 , a P-type differential input stage is shown. The circuit of FIG. 6 illustrates the voltage VCMR as being equal to VDDA−Vgs(MP)−VDSAT(IB).
[0030] Referring to FIG. 7 , a conceptual diagram of the circuit 100 is shown when an input voltage is close to ground. In general, a current Il may be equal to a current Ib−3×Ic/2.
[0031] Referring to FIG. 8 , a diagram of the circuit 100 is shown when an input voltage is close to mid level or close to a supply voltage. In a current IL may be equal to a current Ib−3×Ic/2. In this case, the circuit 104 may be reduced to limit the current IC added to the overall current.
[0032] The terms “may” and “generally” when used herein in conjunction with “is(are)” and verbs are meant to communicate the intention that the description is exemplary and believed to be broad enough to encompass both the specific examples presented in the disclosure as well as alternative examples that could be derived based on the disclosure. The terms “may” and “generally” as used herein should not be construed to necessarily imply the desirability or possibility of omitting a corresponding element.
[0033] While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention.
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The present invention concerns an apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate an output signal in response to a differential input signal, a first power supply and a ground. The output signal may have a rail-to-rail voltage with a magnitude between the first power supply and the ground. The first circuit may also be configured to source an intermediate differential signal in response to the differential input signal, the first power supply and ground. The second circuit may be configured to sink the differential intermediate signal in response to the differential input signal, the first power supply, ground and a second power supply. The second circuit may flatten the transconductance of the first circuit relative to a common mode voltage of the differential input signal.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] Land use and development has become an increasingly important aspect of modern civilization. As more land is required for a variety of reasons, innovative methods of utilizing the remaining land become essential. One traditional use of land is for the burial of the dead. However, traditional methods of burial or interment do not effectively utilize land. Other methods, such as cremation, while conservative with respect to land allocation, are sometimes unacceptable to individuals or their surviving loved ones for religious or other personal reasons.
[0004] Other solutions to the aforementioned land use problem have been suggested. For example, U.S. Pat. No. 5,381,591, issued to Ponger et al. on Jan. 17, 1995, discloses a multi-tier burial system comprising a plurality of precast elements, a first plurality of the elements being aligned to form a first tier defining a plurality of spaced-apart burial niches, and a second plurality of the elements being aligned to form a second tier supported by the first tier also defining a plurality of spaced-apart burial niches, the niches in the second tier being vertically staggered in relation to the niches in the first tier. This solution still requires a substantial area for burial, and situates distinct burial sites in a group of potentially unrelated individuals.
BRIEF SUMMARY OF THE INVENTION
[0005] In accordance with the present invention, a vertical burial system is disclosed. The vertical burial system of the present invention comprises an outer, elongate chamber disposed substantially underground, and at least one burial capsule adapted to fit within the burial chamber. The burial chamber has a cover that is removable, so that as the need arises, additional burial capsules may be placed in the elongate burial chamber. The present invention thus simulates traditional burial, but conserves precious land by allowing multiple burials within the elongate burial chamber. The burial system of the present invention is particularly well suited for grouping families or relatives within a discrete burial site.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0006] The objects of the invention are achieved as set forth in the illustrative embodiments shown in the drawings which form a part of the specification.
[0007] [0007]FIG. 1 is a cross sectional view of an elongate burial chamber of the present invention;
[0008] [0008]FIG. 2 is a side elevational view of a burial capsule of the present invention;
[0009] [0009]FIG. 3 is a cross sectional view of ground prepared to receive an elongate burial chamber of the present invention;
[0010] [0010]FIG. 4 is a cross sectional view of an elongate burial chamber of the present invention disposed in the ground with a single burial capsule;
[0011] [0011]FIG. 5 is a cross sectional view of an elongate burial chamber of the present invention disposed in the ground with multiple burial capsules;
[0012] [0012]FIG. 6 is a side view of a burial capsule of the present invention;
[0013] [0013]FIG. 7 is a top plan view of a burial capsule of the present invention;
[0014] [0014]FIG. 8 is a front plan view of a burial capsule of the present invention;
[0015] [0015]FIG. 9 is top plan view of an array of burial chambers of the present invention; and
[0016] [0016]FIG. 10 is a side elevational view of an array of burial chambers of the present invention.
[0017] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF INVENTION
[0018] Referring to the drawings, and in particular to FIG. 1, a vertical burial system of the present invention has an elongate, outer burial chamber 1 comprising an elongate chamber portion 3 and a cover 11 . The elongate chamber portion 3 is defined by an inner wall 5 and an outer wall 7 . The cap 11 has an upper end 13 and a lower end 15 . Near the top of the chamber portion 3 , internal threads 6 are adapted to receive the external threads 16 of the bottom end 15 of cap 11 . In the preferred embodiment of the present invention, an opening 19 extends from the upper end 13 through the lower end 15 of the cap 11 . A vent tube 21 is disposed toward the upper end 13 of the cap 11 , and preferably extends a distance above the upper end 13 of the cap 11 . In an especially preferred embodiment, a carbon filter 23 is situated within the vent tube 21 . The lower end 24 of the vent tube 21 extends a distance into the opening 19 , and preferably extends completely through the opening 19 and the lower end 15 of the cap 11 .
[0019] Referring now to FIG. 2, a burial capsule of the present invention is generally shown at 30 . The length and width of the burial capsule 30 is determined by the remains of the deceased to be buried, so that the burial capsule may configured to hold the body of an adult, or a smaller version may be required to hold the body of a child. Preferably, the length of the burial capsule will be that length sufficient to hold a body in an extended, supine position. In the preferred embodiment of the present invention, the burial capsule 30 is formed as a clamshell, with an upper portion 33 and a lower portion 35 . In the closed position of burial capsule 30 , the upper portion 33 meets the lower portion 35 at seam 37 . In the preferred embodiment of the present invention, a vent 39 allows gasses evolved during decomposition of a corpse to be released from the interior of the capsule 30 . In an especially preferred embodiment of the burial capsule 30 , the vent 39 allows gasses to escape without admitting gasses from the exterior of the capsule 30 . The burial capsule 30 may be fabricated in a number of colors, depending upon the wishes of the deceased or the family of the deceased.
[0020] Referring now to FIG. 3, a prepared site for a burial system of the present invention is shown. The ground 43 may be prepared by digging, blasting, boring with an auger, or other effective means of creating an opening 45 in the ground 43 . The opening 45 should of course be sufficient to allow the outer surface 7 of the elongate chamber 3 to be placed within the opening's confines.
[0021] Referring now to FIG. 4, a burial capsule 30 is shown inside the elongate chamber 3 . As gasses are evolved during decomposition of a corpse inside the burial capsule, those gasses escape through the vent 39 into the elongate chamber portion 3 , and finally into the atmosphere through the vent tube 21 in the cap 11 . A monument or headstone 48 may be installed at or near the burial system. Optionally, the monument 48 may partially obscure the vent 21 , and in this regard, the monument 48 may additionally be fabricated to accommodate a portion of the vent 21 , for further concealment, such as with, for example, a cavity (not shown) formed within monument 48 for partially concealing vent 21 .
[0022] Referring to FIG. 5, a plurality of burial capsules 30 , 50 and 53 are shown disposed inside the elongate chamber 3 . As can be seen from this illustrative embodiment, the lower end 24 of vent tube 21 is spaced a distance from the uppermost burial capsule 53 . It is to be understood that more than the illustrative number of burial capsules may be disposed in the elongate chamber 3 in the practice of the present invention, and that a corresponding adjustment to the length of elongate chamber 3 enables a larger or smaller number of burial capsules to be so disposed. Furthermore, the size of one or more burial capsules may be different within a single elongate chamber.
[0023] Referring now to FIGS. 6 - 8 , and alternative embodiment of a burial capsule 60 is shown. Burial capsule 60 is preferably formed in two cooperating portions, and therefore has a top portion 63 , a bottom portion 65 , and a center seam 67 . Center seam 67 is the point of closure for the top portion 63 and the bottom portion 65 . Center seam may be hinged on one side, such that top the portion 63 and the bottom portion 65 are attached, or alternatively the top portion 63 and the bottom portion 65 may be separate pieces. Preferably, a vent 69 is disposed in either the top portion 63 or the bottom portion 65 of the burial capsule 60 . The vent 69 allows gasses evolved during decomposition of a corpse to be released from the interior of the capsule 60 . Of course, the burial capsule 60 may be formed without the vent 69 , and may be fabricated from a gas permeable material, or have holes incorporated for release of gasses. Furthermore, the burial capsule 60 may alternatively have no accommodation for evolved gasses, and may be sealed, for example.
[0024] In this alternative embodiment of a burial capsule or the present invention, plurality of rings 71 , 73 , 75 , and 77 are formed in or near the center seam 67 of the burial capsule 60 . The rings 71 , 73 , 75 , and 77 provide convenient attachment points for raising or lowering the burial capsule 60 into an elongate chamber of the present invention. Additionally, the rings 71 , 73 , 75 , and 77 may be used for carrying the burial capsule 60 from a funeral home, for example, to the burial site. It will be appreciated by those skilled in the art that the rings 71 , 73 , 75 , and 77 may be oriented either parallel to the plane defined by the longitudinal axis of the center seam 67 of the burial capsule 60 , or at an angle or transverse to the plane defined by the longitudinal axis of the center seam 67 . Alternatively, the rings may swivel, such that in one orientation, the rings are parallel to the plane defined by the longitudinal axis of the center seam 67 of the burial capsule 60 , for example, and movable into a position transverse to the plane defined by the longitudinal axis of the center seam 67 . In this embodiment, when the rings are placed in their parallel orientation, a rod (not shown) may be placed through the rings on each side of the burial capsule 60 for carrying the burial capsule 60 to a destination, for example to the elongate chamber. Once at the destination, one or all of the rings may then be moved into the transverse position, for receiving a hook, for example, for lowering the capsule 60 into an elongate burial chamber 3 .
[0025] Referring now to FIGS. 9 and 10, a burial complex 80 comprises a plurality of interconnected burial systems 3 , 83 , 85 , 87 , 89 , and 91 . The burial systems 3 , 83 , 85 , 87 , 89 , and 91 are preferably interconnected by beams 82 , 84 , 86 , 88 , and 90 , respectively. The beams 82 , 84 , 86 , 88 , and 90 are preferably attached to respective burial systems 3 , 83 , 85 , 87 , 89 , and 91 at a point below the respective caps, for example. Preferably, a second set of beams, 92 , 94 , 96 , 98 , and 100 interconnect burial systems 3 , 83 , 85 , 87 , 89 with burial system 91 . It is to be understood that any number of burial systems may be interconnected with corresponding beams, and the illustrative example of six burial systems is not intended to be limiting. Beams 82 , 84 , 86 , 88 , and 90 , along with beams, 92 , 94 , 96 , 98 , and 100 provide a strong, stable interconnection between burial systems 3 , 83 , 85 , 87 , 89 , and 91 . Alternatively, the beams may be pre-attached one to another, such that a frame is established. The frame may have round members at the remote ends of the beams, and the round members may have openings therein, for receiving respective elongate chambers.
[0026] It is contemplated by the present invention that locations previously considered too inhospitable for traditional burial, such as areas with highly water saturated earth, for example may be used for burial utilizing the burial complex 80 . It is also contemplated by the present invention that one or more burial systems in the burial complex 80 may have weights or other anchoring devices for stabilizing the burial complex 80 in such environments.
[0027] Numerous variations will occur to those skilled in the art in light of the foregoing disclosure. For example, a traditional coffin may be temporarily used to carry a burial capsule from a funeral facility to a burial facility. The elongate burial chamber may be made from a variety of materials. The elongate burial chamber may be made in a shape other that the illustrative generally cylindrical form. The cap of the elongate burial chamber may optionally omit a vent, and the elongate burial chamber may be made of a gas permeable material, have holes, or make no provision at all for gasses evolved during the decomposition of a corpse disposed therein. The burial capsule may also be fabricated from a variety of materials. These are merely illustrative.
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A vertical burial system is disclosed. The vertical burial system of the present invention comprises an outer, elongate chamber disposed substantially underground, and at least one burial capsule adapted to fit within the burial chamber. The burial chamber has a cover that is removable, so that as the need arises, additional burial capsules may be placed in the elongate burial chamber. The present invention thus simulates traditional burial, but conserves precious land by allowing multiple burials within the elongate burial chamber.
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BACKGROUND OF THE INVENTION
The invention relates to a tool with self-locking grip, interchangeable head-pieces and clamp for fastening to a work bench.
DESCRIPTION OF THE RELATED ART
It is well known that there is currently a vast range of work tools made up essentially of two levers, also known as gripping arms, which are permanently fastened to the handle, with at least one of the gripping arms or levers being mobile.
Jaws are generally provided at the end of the arms, for holding a workpiece. In some cases the ends of the arms comprise devices specially adapted to some operations, for example, for cutting a pipe, punching holes, etc.
These work tools are generally designed to perform just one task, depending on the type and shape of the jaws, the means provided for regulating the distance between the ends of the arms, and the possibility of locking the arms using a specific self-locking system.
For this reason, there is an almost endless variety of two-gripping arms tools on the market today, the more common of which being: self-locking pliers with screw-adjustment of the distance between the jaws and the locking pressure; adjustable pipe wrenches which allow the distance between the jaws to be set; wrenches featuring one movable jaw which slides along a worm screw-lead screw system; pipe cutters with cutting wheel set at the end of at least one of the gripping arms; punches for punching holes in soft sheet material, etc.
As a result, different operations normally require the purchase of different tools with greater expense and transport and handling problems.
U.S. Pat. No. 2,312,425 describes a wrench wherein it is easy to place the jaws in gripping relation to the work, and having interchangeable jaws of different contours, suitable to particular types of work.
The wrench comprises an elongated flat transversely rectangular casing having an open end and a closed end, and an elongated longitudinal slot in one edge thereof, a pair of jaw members having flat shanks extending into said open end of the casing and relatively slidable in edge-to-edge engaging relation therein, inwardly and outwardly of said open end, respectively, into different positions, detent means for releasably holding one shank in different positions, a spring in said casing having its ends fastened to the inner end of the other shank and to the closed end of the casing, respectively, in the line of movement of said other shank and tensioning said other shank against outward sliding, and means to slide said other shank outwardly in opposition to said spring comprising a lateral edge lug on said other shank extending into the slot in said one edge of the casing flush with said edge, a pair of opposed ears extending from said one edge of the casing at opposite sides of said slot, a cam pivoted between said lugs and having a handle and a radial shoulder rotatable into said slot into camming engagement with said lug.
The main disadvantages of the wrench consist in that is difficult to unfasten the spring and to interchange the shank without disassembling the casing.
The interchangeability is theoretic more than practical.
Moreover, the thickness of the object to be gripped does not allow the handle to find a rest in the casing.
Furthermore, the user must hold the wrench in his hand while he is working, and this means that one hand is constantly engaged.
Finally, the compression of the handle always causes the lower jaw to move towards the upper jaw, whereas in some works it is more convenient that the upper jaw moves towards the lower one.
In U.S. Pat. No. 2,149,541 a wrench is disclosed having a handle and a pair of complemental jaws. The jaws have some type of removable jaw members attached to the regular jaws of the wrench, in order to provide alternatively a smooth flat clamping surface on the jaws, or a punch member, or a cutting pipe device.
The main defect consists in that the jaws are not interchangeable, but may just be fitted by applying thereto devices of reduced dimensions, which aren't practical and are weak. Further disadvantages consist in that the wrench lacks a device for blocking the jaws in position, and that the push of the user on the handle is not balanced, thus forcing the user himself to use not only one, but both hands to do his work.
Furthermore, none of the more commonly available tools has the option of being fastened directly to the work bench; indeed, even tools designed to hold two objects for operations such as welding or gluing, must be fastened to the bench using a traditional vice, in order to allow the user to have both hands free.
Said bench vice, may also damage or deform the handle of the tool.
SUMMARY OF THE INVENTION
The aim of this invention is to eliminate all of the problems described above.
In particular, the main objective of the invention is to realize a tool with removable and interchangeable gripping arms, for performing a wide variety of tasks.
A further objective is the possibility of fastening the tool to the work bench using a specific, incorporated device, which is operated by the same self-locking system of the arms.
These and other objectives are fulfilled by the invention, a self-locking tool comprising a handle, two gripping arms and a self-locking system, wherein the handle of the tool comprise a main body with two prismatic housing-guides, holding and guiding said two arms; the arms are removable and interchangeable with other arms and fitted with ends adapted for performing a range of mechanical functions; the self-locking device is connected between the body of the handle and one of the arms, so that operation of the device causes a sliding of said one of the arms, whose end approaches the end of the other gripping arm, this last being fixed inside its housing, to give a gripping effect and locking into position when closed.
The main body of the handle contains at least a third prismatic housing-guide, for a further removable gripping arm at the opposite end of the handle; this arm being connected to the same self-locking device and sliding inside its housing, for fastening the tool to a workbench, in cooperation with a fixed element.
Moreover, the gripping area of the ends of the arms is advantageously fitted with removable devices which can be easily replaced.
The advantages of this invention consist, in general, in the fact that several different applications can be performed using one single handle, costs for the purchasing of a complete kit of tools are reduced, and the user can work alone, without using a vice to clamp the wrench.
Further advantages are the possibility to obtain a greater opening of the jaws at the end of the gripping arms; the possibility to have a progressive pressure between the end of the gripping arms using a claw device, fitted in the self-blocking lever (useful, for example, when cutting pipes); the high force allowed by the kinematic movement of the self-locking lever (useful for example, to trim or punch), etc.
BRIEF DESCRIPTION OF THE DRAWINGS
Finally, further characteristics and advantages of the invention will be better highlighted by the more detailed description as follows, with the help of drawings showing some preferred embodiments and common applications. The drawings are provided as examples only, and do not represent the complete range of possibilities.
FIG. 1 shows a side view with hidden lines dashed, of the self-blocking tool in grip closed position, the principle version of this invention.
FIG. 2 shows a side view of the same tool, in open release position.
FIG. 3 shows a side view with hidden lines dashed, the self-blocking tool in grip closed position, one possible variation.
FIG. 4 shows the same variation of the tool as in FIG. 3, in open release position.
FIG. 5 shows a side view with hidden lines dashed, the self-blocking tool in grip position closed, a further possible variation.
FIG. 6 shows the same variation of the tool as in FIG. 5, in open release position.
FIG. 7 shows a side view of the interchangeable gripping arms of the tool.
FIG. 8 shows an exploded perspective view of the jaws at the ends of the interchangeable gripping arms, with an example of the replaceable grip zone.
FIGS. 9, 10 , 11 , and 12 show a side view of the tool respectively and illustratively fitted with jaws for holding objects in place for operations such as welding or gluing, jaws for tightening or loosening bolts, jaws with a pipe cutting device, and jaws with a device for punching holes.
FIG. 13 shows an exploded perspective view of the fixed element for the locking jaw of the tool, in the versions illustrated in FIGS. 1, 2 , 3 , and 4 .
FIG. 14 shows a perspective view of the sliding block on which the manoeuvring lever of the self-blocking lever device pivots.
FIG. 15 shows a perspective view of the ratchet of the handle, which allows the tool to be fastened to the work bench.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the details shown in the figures, the invention features a handle 1 , two gripping arms 2 a and 2 b , and a self-locking lever device 3 .
The handle of the tool 1 comprises a main body 45 , with two internal prismatic housing-guides 4 a and 4 b , holding and guiding respectively the two arms 2 a and 2 b.
Each of the arms 2 a and 2 b comprises a prismatic portion 5 a , 5 b which can be inserted in the two prismatic housing-guides 4 a and 4 b , and external ends 6 a and 6 b , which remain external to the main body upon insertion.
The gripping arms 2 a and 2 b are thus removable and interchangeable with other gripping arms, provided that each of said interchangeable gripping arms comprise a prismatic portion, substantially identical to said prismatic portions 5 a and 5 b , and is fitted with an external end adapted to the use. For example, external ends of the gripping arms may work as jaws as shown in FIGS. 1 to 10 , or support other tools, as shown in FIGS. 11 and 12.
In the case where ends 6 a and 6 b work as jaws, their gripping portions 7 a and 7 b are fitted with a track guide 46 , which allows their replacement to modify the shape of the gripping zone or to change the grip materials.
Both the shape and the materials of the gripping portions may be varied according to the requirements of the application.
The materials which may be used include rubber, Teflon, copper, etc., in addition to the standard steel.
The prismatic portion 5 a of arm 2 a comprises, on one side, selective locking means, which in the embodiments shown are obtained with a rack 8 .
Furthermore, the main body 45 of the handle 1 comprises a third prismatic housing-guide 9 , for housing and guiding a third gripping arm 10 .
The gripping arm 10 comprises a prismatic portion 11 which can be inserted in the prismatic housing-guide 9 , and an end 12 working as a jaw.
The prismatic portion 11 of arm 10 also features, on one side, selective locking means 13 , which in the embodiment shown are saw-tooth shaped, like those of the gripping arm 2 a.
A removable element 14 , having a gripping portion 15 adapted to cooperate with the corresponding gripping portion of the jaw 12 for fastening the tool to a workbench, is associated to body 45 , with locking means 48 or 49 .
The self locking lever device 3 is connected to the main body 45 and to one of the gripping arms, namely the arm 2 a or the arm 2 b , so that the operation of the device 3 cause said gripping arm to slide inside its guide 4 a or 4 b , the external end of said arm thus moving towards the end of the other gripping arm, where this last is fixed, giving a gripping effect. Moreover, the device 3 is adapted to lock said gripping arm into position, when closed.
With reference to the embodiment of the tool shown in FIGS. 1 and 2, the self-locking device 3 comprises a manoeuvring lever 16 , a spike 17 , a sliding block 18 and a saddle 19 .
The manoeuvring lever 16 is pivoted on the sliding block 18 using a pin 20 and connected to saddle 19 through a cam 21 , as shown in FIG. 1, or otherwise using a rod 44 , as shown in the alternative versions of FIGS. 3 and 4.
The spike 17 is pivoted on the manoeuvring lever 16 using a pin 47 and is engaged with a rack 22 on the sliding block 18 by the effect of a spring 23 .
The spike 17 and the rack 22 allow multiple locking positions of the manoeuvring lever 16 .
A worm screw and nut screw device, made up of a reel 24 pivoted on the sliding block 18 and engaged with a nut screw 25 , housed in the main body 45 of handle 1 , allow small movements of the sliding block 18 along the rail guide 34 , and consequently of the manoeuvring lever 16 , for adjusting the gripping force between the ends 6 a , 6 b , 12 and 15 .
The saddle 19 slides in both directions along the main body 45 , contrasted by the spring 35 .
The saddle 19 is connected to arm 2 a through a connection device 26 , fitted with teeth adapted to engage the rack 8 .
This device 26 is meshed in the saddle 19 using rail-type connection means, adapted to remove it from rack 8 , for disconnecting the saddle 19 from arm 2 a , and moving the arm to the desired starting position.
The saddle 19 , finally, is also connected to arm 10 using a pawl 27 , fitted with teeth adapted to engage rack 13 , due to the action of a spring 28 .
The pawl 27 is also fitted with a pin 29 which slides or rotates along the surfaces bordering the slotted holes 30 and 31 , on the main body of handle 1 and the saddle 19 , as well as with a second pin 32 which slides in slotted hole 33 on saddle 19 , and, if required, horizontally in a slotted hole 50 of the main body 45 , countered by spring 28 .
The first pin 29 allows selective engagement of means blocking the pawl 27 , e.g. a hook 36 pivoted to the main body 45 of handle 1 .
The second pin 32 is pushed towards the teeth 13 by the spring 28 housed in the main body 45 .
In a second version of the tool, as illustrated in FIGS. 5 and 6, the saddle 19 is replaced with a block 37 which slides inside guide 4 b of arm 2 b.
This block 37 is connected to manoeuvring lever 16 using a connecting rod 38 and to arm 10 using a rod 39 , at the lower end of which is fastened a rotating reel 40 , a portion of the side surface of which is fitted with teeth 41 engaging the teeth 13 .
In this version, arm 10 is inserted into a prismatic guide which is coaxial to that of arm 2 a ; the position of the arm 10 can be selectively blocked as required using a locking device 42 of teeth 13 fixed to the main body 45 of handle 1 .
In a further version of the device, which is not illustrated, arm 10 is absent and element 14 is replaced by magnetic fastening means.
In the preferred embodiment of the tool, arm 2 a can be inserted in housing 4 a by disconnecting device 26 , while arm 2 b can be directly inserted into housing 4 b.
The connecting device 26 also allows the setting of the initial distance between jaws 6 a and 6 b.
Arm 10 can be disconnected (or inserted) from housing 9 by disconnecting pawl 27 , acting on pin 32 which can horizontally slide in slotted hole 33 , against the force of spring 28 .
Element 14 can be fastened at the end of the main body 45 of handle 1 using locking elements 48 of known type.
Acting on manoeuvring lever 16 , the saddle 19 slides downwards, dragging arm 2 a , whose end 6 a approaches end 6 b of lever 2 b , which remains fixed in its housing.
At the same time, pin 29 slides along slotted hole 30 , dragged by slotted hole 31 .
In this way the toothed side of pawl 27 engaging rack 13 of arm 10 , makes it slide upwards, causing the end 12 to approach the grip portion 15 of element 14 .
This movement allows the vice, made up of jaws 12 and 14 , to fasten the tool to a protruding part of a work bench.
Lever 16 is kept in position by spike 17 which meshes in the teeth 22 of block 18 , thanks to the action of spring 23 .
In this way it is possible to keep a fixed distance both between end 6 a and 6 b of gripping arms 2 a and 2 b , and between the end jaw 12 of arm 10 and the grip portion 15 of element 14 .
Reel 24 can be used to adjust the pressure on the object tightened between these elements with greater precision.
To fasten the grip of the jaws 10 and 14 , hook 36 acting on pawl 27 can be used. In this way, even further upward movement of saddle 19 will not separate arm 10 from element 14 , keeping the tool fastened to the work bench.
As a consequence, the fine adjustment of the pressure between arms 2 a and 2 b or 10 and 14 , using reel 24 , can be performed independently, depending on whether the hook 36 is inserted or not.
In the second version of the tool, acting on manoeuvring lever 16 , block 37 slides inside housing 4 b , pushing arm 2 b upwards, whose end 6 b approaches end 6 a of arm 2 a.
At the same time, rod 39 slides and drags the arm 10 , via reel 40 , whose teeth 41 are meshed in rack 13 .
To block the arm 10 and free the movement of arms 2 a and 2 b from the movement of arm 10 , the user can turn the reel 40 , so as to disengage teeth 41 from rack 13 .
This operation thus allows the upper section of the tool, made up of gripping arms 2 a and 2 b , to be made independent from the lower portion (or vice), made up of elements 10 and 14 , which can remain closed even when the lever 16 is opened.
For removing arm 10 from its housing, the user removes the locking element 42 from rack 13 , after disengaging teeth 41 of the reel 40 .
To remove arm 2 a from its housing 4 a , the user must disconnect the teeth of locking element 43 , fastened in a removable manner to handle 1 , from teeth 8 of arm 2 a.
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Tool with self-locking grip featuring a handle ( 1 ), two levers ( 2 a ) and ( 2 b ), and a self-locking device ( 3 ), in which the handle ( 1 ) features a main body ( 45 ), containing two prismatic housing-guides ( 4 a ) and ( 4 b ) which hold the two levers. These are removable and interchangeable with other levers for performing different mechanical functions, where the self-locking device ( 3 ) is kinetically connected between the main body ( 45 ) and one of the levers. The main body ( 45 ) also contains a third prismatic guide ( 9 ) for a further removable lever ( 10 ); this lever, being connected as required to the same a self-locking device ( 3 ) and sliding inside its own housing, approaching a counter element ( 14 ) fixed to the main body ( 45 ) allows vice-like fastening of the tool to a protruding part of the work bench.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to noise control in suspended ceilings. Such suspended ceilings have a grid of intersecting metal beams that are suspended by hangers from a structural ceiling. Panels or drywall sheets are supported on the grid.
[0003] Noise generated in the structural ceiling, which is frequently a floor for the space above, is transmitted by sound vibrations passing downward through the hangers, which form a sound path, to the grid of the suspended ceiling. The suspended ceiling, which includes panels or drywall sheets attached to the beams in the grid, forms a receiver for the sound vibrations, which broadcasts the resulting unwanted noise to the space below.
[0004] The invention deals with deadening such sound vibrations coming down the hangers.
[0005] 2. Prior Art
[0006] Suspended ceilings are constructed in a special way so that the ceilings are extremely stable. Over many years, a standard way of constructing such ceilings has evolved. Suspended ceilings are constructed at a building site by individually explosively embedding an anchor such as an eye bolt, into the structural ceiling, and then attaching a hanger, such as a wire, to the anchor, by twisting the wire about the anchor. The lower end of the hanger is attached to a metal beam in a grid that supports panels, or drywall sheets, by looping the hanger through a hole in the web of the beam and twisting the loop closed around the bulb and a segment of the beam.
[0007] The substantial weight of the suspended ceiling is spread among numerous hangers that are spaced every few feet along the main beams in the grid. Each hanger must be individually secured to the structural ceiling, and to the grid beam, by an installer who must keep the grid of interconnected main and cross beams level at a desired height. Much time and effort is required to hang a suspended ceiling grid from a structural ceiling.
[0008] Much more time and effort is required where sound attenuator devices that dampen the vibrations coming down a hanger sound path, from noise generated in a structural ceiling, are used.
[0009] In the prior art, to control noise in a suspended ceiling, a noise attenuator is individually inserted by the installer, about midway in the length of a wire hanger that is cut into two segments. An upper segment of the wire hanger is first secured at its top to the structural ceiling, and at its bottom, to a top terminal in the attenuator. A lower segment of the wire hanger is connected at the top to a bottom terminal in the attenuator, and then, at the bottom of the lower segment, to the grid beam.
[0010] In such prior art attenuator, the upper and lower metal terminals are separated from each other by a suitable amount of sound vibration damping material, such as gum rubber. Sound vibrations coming down the wire hanger sound path from the structural ceiling, which frequently serves as a floor for the building level above, are absorbed in the noise attenuator.
[0011] The insertion of such prior art noise attenuators in a wire hanger that must be divided into two segments is time and labor consuming, since the normally single segment of a wire hanger must not only be divided into two segments, but each segment must then be secured to the noise attenuator by passing the hanger through an attenuator terminal, and then twisting the hanger back around the segment. Thus, instead of just two attachments of a single segment of a wire hanger at an upper end to the structural ceiling, and at its lower end to a grid beam itself, as in prior art suspended ceilings with no noise attenuation, there are two additional attachments involving threading the wire hanger through a hole, and then twisting the wire hanger back upon itself, to the noise attenuator.
[0012] Such manual cutting, threading, and twisting must be individually custom performed by the installer of the grid in the field during the construction of the ceiling, since good judgment must be exerted at each wire hanger to keep the grid level, through controlling the length of the wire hanger suspensions.
BRIEF SUMMARY OF THE INVENTION
[0013] A noise damper, of material that deadens sound vibrations coming down a hanger, is inserted between the grid beam and a hanger in the construction of the suspended ceiling.
[0014] The noise damper insulates the entire hanger attached to the structural ceiling from contact with the metal grid beam in the suspended ceiling, so the sound vibrations passing down the hanger are deadened in the noise damper. The noise damper, however, does not interfere with the structural support of the grid beam and suspended ceiling by the hangers, which are generally of wire, but permissibly of other material having adequate tensile strength to support the suspended ceiling.
[0015] The time required to install a suspended ceiling with the present invention is virtually the same as the time required to install a prior art suspended ceiling without any noise damping. In the present invention, the noise damper, which is of a resilient, sound vibration deadening material, can be merely inserted into place, and the hanger attached to the beam by looping a wire hanger through a knock-out in the beam, as done in the prior art in a suspended ceiling that is not sound dampened.
[0016] The knock-out can be shaped so the stress that the suspended ceiling imparts to the hanger where it passes through the knock-out is distributed over a section of the noise damper, rather than concentrated at the site of the hanger.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWING
[0017] FIG. 1 is a perspective view of the noise damper of the invention.
[0018] FIG. 2 is an elevational view comparing
(a) a prior art suspended ceiling segment without noise damping; (b) a prior art ceiling segment with noise damping; and (c) a suspended ceiling with the noise damper of the invention
[0022] FIG. 3 is a side elevational view of a noise damper in place on a grid beam with a wire hanger looped through the noise damper and beam.
[0023] FIG. 4 is an exploded perspective view of a section of a grid beam showing a knock-out that seats a conforming raised section of a noise damper.
[0024] FIG. 5 is an enlarged sectional view taken on the line 5 - 5 in FIG. 3 .
DETAILED DESCRIPTION OF THE INVENTION
[0025] Although the invention is illustrated with hangers of wires, which is the predominant material used to suspend present day ceilings, the invention can be used with other forms of hangers, such as rods, or chains.
[0026] In FIG. 2 , there is shown comparatively (a) a prior art ceiling without noise damping; (b) a prior art ceiling with noise damping; and (c) the noise dampened suspended ceiling of the present invention. In a prior art suspended ceiling installation without noise damping, ( FIG. 2 a ), the suspended ceiling 43 , is hung from a structural ceiling 22 , by wire hangers 40 embedded in the structural ceiling at the top, and looped through about the grid beam 21 at the bottom. A single length of wire hanger 40 is used.
[0027] In FIG. 2 b , a wire hanger is cut in two into segments, 23 and 24 , and secured to the structural ceiling 22 and suspended ceiling 43 as shown. A grid beam 21 is suspended from structural ceiling 22 by an upper wire segment 23 and a lower wire segment 24 , connected to a sound attenuator 25 . The upper wire segment 23 is looped through an eye bolt 26 explosively embedded in the structural ceiling 22 , and manually twisted to close the loop 27 . Similar connections are made to sound attenuator 25 at the bottom of segment 23 and at the top of the lower segment 24 . At the bottom of the lower segment 24 , there is formed a loop 27 that passes through a hole 28 in the web 29 of grid beam 21 . The loop 27 is closed by twisting the wire hanger segment 24 .
[0028] In the present invention, as shown in FIG. 2 c , a single length of wire hanger 40 is used to suspend a beam 21 at suspension points along the beam 21 . A noise damper is inserted onto grid beam 21 between the suspension loop 42 at the bottom of wire hanger 40 and the grid beam 21 , to insulate the beam 21 from the wire hanger 40 . The noise damper 41 of the invention deadens the sound vibrations from structural ceiling 22 as they travel down the wire hanger 40 , before the vibrations reach the metal grid beam 21 , in the suspended ceiling 43 , which would serve as a receiver that would broadcast the noise to the space below.
[0029] At the top, the wire hanger 40 is looped through eye bolt 26 explosively embedded in structural ceiling 22 , and the loop 44 is twisted closed. The lower end of wire hanger is passed through hole 61 in noise damper 41 on grid beam 21 , and passes through knock-out 46 .
[0030] Noise damper 41 has an inverted U-shaped upper portion 47 conforming in cross section to the bulb 48 of the grid beam 21 , as seen particularly in FIG. 5 . A flat lower portion 51 is intended to lie along the web 29 of the grid beam 21 as seen in FIG. 5 .
[0031] A raised insert 53 on flat lower portion 51 is shaped to conform to a knock-out 46 , desirably with the shape of an arch 56 at the top. Lip retainers 57 hold the raised insert 53 firmly in the knock-out 46 . An angled lip 58 on the U-shape clip portion 47 retains such U-shaped portion 47 of the noise damper 41 on the bulb 48 of the grid beam 21 . A hole 61 that receives wire hanger 40 extends through the raised insert 53 and knock-out 46 .
[0032] The noise damper 41 is injection molded into one resilient integral piece from a vibration deadening material. An example of such a material is thermoplastic vulcanizate, an elastomer, that includes carbon black and a paraffin wax. Such material, in pellet form, is injection molded into the form of the noise damper 41 insert of the invention. The noise damper 41 , when molded, is flexible, and can readily expand when being inserted onto the grid beam 21 , to envelope the grid beam 21 as depicted in the drawings.
[0033] The noise damper 41 is inserted onto the beam by passing the inverted U-shape portion 47 vertically downward over the bulb 48 of grid beam 21 to seat raised insert 53 in knock-out 46 . The noise damper 41 expands while being inserted onto the grid beam 21 , and contracts to the position about the beam 21 , and into knockout 46 , as shown particularly in FIGS. 3 and 5 .
[0034] A single length of wire hanger 40 , which has been embedded previously in the structured ceiling, is then looped through the hole 61 in the noise damper 41 , as shown in FIG. 5 , and then twisted at 62 to close the loop.
[0035] In this manner, the metal wire hanger 40 is insulated from metal grid beam 21 , while still structurally supporting the grid beam 21 .
[0036] A series of wire hangers 40 and noise dampers 41 are applied at, for instance, four (4) foot intervals along the main grid beams 21 . The knock-outs 46 may be pre-punched at more frequent intervals, along the beam, and the noise dampers inserted selectively. The knock-outs 46 do not appreciatively affect the strength of the grid beams 21 .
[0037] By means of the present invention, as set forth above, the hanger 40 which acts as a sound path from the structural ceiling 22 noise source to the suspended ceiling 43 which acts as a receiver is interrupted and dampened by the noise damper 41 of the invention.
[0038] The noise dampers 41 can be inserted at the job site as the grid beams 21 are being hung, or in the alternative, the noise dampers 41 can be inserted on the grid beams 21 before the grid beams 21 themselves are shipped to the job site.
[0039] In case of a fire, even though the noise dampers 41 of the invention are destroyed, wire hangers 40 continue to support the grid beams 21 , since the wire hangers 40 remain attached to the grid beams 21 .
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Noise dampers of sound absorbent material are inserted on the metal grid beams in a suspended ceiling.
Hangers, embedded in a structural ceiling, that support the beams, are insulated from the beams by the noise dampers.
Sound vibrations generated in the structural ceiling, which is often a floor, are not transmitted through the hangers, to the suspended ceiling, or to the room, below, but are absorbed in the dampers before reaching the grid beams.
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TECHNICAL FIELD
This invention relates generally to a blade control system having a pair of master/slave cylinders which provide a first stage fluid flow regeneration and more specifically to a system having a second stage of fluid flow regeneration.
BACKGROUND ART
The use of a pair of hydraulic cylinders in a master/slave series flow relationship to achieve faster actuating speed of the hydraulic cylinders is well known. Typically, the rod end chamber of the master cylinder is connected to the head end chamber of the slave cylinder so that fluid discharged from the rod end chamber of the master cylinder is directed to the head end chamber of the slave cylinder when pressurized fluid is directed to the head end chamber of the master cylinder. The fluid exhausted from the rod end chamber of the slave cylinder is typically directed to the tank. Heretofore, the cylinders in a master/slave relationship have been identical in size and construction. One example of a system including the master/slave feature is disclosed in U.S. Pat. No. 4,802,537.
With the control system disclosed in the above-noted patent, the volume of fluid discharged from the rod end chamber of the master cylinder for each increment of movement of the piston rod is less than the volume of pressurized fluid directed to the head end chamber of the master cylinder. This results in the master cylinder extending a greater distance and faster than the slave cylinder. However, the blade of the '537 patent controlled by the pair of master/slave hydraulic cylinders is basically used for dozing operations and does not require very large fore and aft tipping motion. Thus, the stroke of the cylinders is relatively short and the disparity in the extension of the cylinders does not unduly affect the operation of the earthmoving blade.
The above reference to unequal extension rates of the hydraulic cylinders is a problem when the pair of master/slave hydraulic cylinders are connected to a "carry dozer" blade requiring much larger tipping motions of the blade to dump the material from the blade. More specifically, a significant amount of material remains on the side of the blade controlled by the slave cylinder when the master cylinder reaches its limit of,extension. Finally, the carry dozer is typically used in mass excavating types of operation and it would be desirable to dump the load faster than that obtained solely by the master/slave arrangement without drastically increasing the size of the supply pump. Moreover, it would be desirable to increase the extension speed of the slave cylinder to match the extension speed of the master cylinder so that both sides of the blade reach their maximum dumping position at the same time.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, a blade control system includes a pump connected to a tank, and first and second hydraulic cylinders disposed on opposite sides of a machine and between the machine and an earthworking blade. A directional control valve is connected to the pump and the tank and has first and second control ports. The directional control valve has an operative position communicating the pump with the first control port. A fluid regeneration valve is connected to the first and second control ports of the directional control valve and has a cylinder port and a valve port with the cylinder port being connected to the head end of the first cylinder. The fluid regeneration valve has an operative position at which the first control port of the directional control valve communicates with both the cylinder and valve ports. A selector valve is connected to the valve port of the fluid regeneration valve and has a second cylinder port connected to the rod end of the first cylinder, a third cylinder port connected to the rod end of the second cylinder and a fourth cylinder port connected to the head end of the second cylinder. The selector valve has an operative position communicating the rod end of the first cylinder with the head end of the second cylinder and the rod end of the second cylinder with the valve port of the fluid regeneration valve.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of an embodiment of the present invention; and
FIG. 2 is an elevational perspective view of a representative blade which is variably positioned by the blade control system of the present invention and further illustrating in fragmentary phantom outline a representative machine on which the blade is pivotally mounted.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, a blade control system 10 is illustrated for positioning an earthworking blade 11 suitably mounted on a machine 12. The machine includes a pair of push arms 13 mounted on opposite sides of the machine 12 through a pair of universal connections 14. The blade is pivotally connected to the forward ends of the push arms 13 by a pair of universal connections 16. A pair of double acting hydraulic lift cylinders 17 are coupled intermediate the machine and the blade for raising and lowering the blade in the usual manner. A pair of double acting hydraulic tilt/tip cylinders 18,19 are disposed on opposite sides of the machine between the push arms 13 and the blade 11 for tilting and tipping the blade relative to the machine. Each of the tilt/tip cylinders 18,19 have a rod end chamber 20 and a head end chamber 21.
It should hereinafter be appreciated that in this application, tilting is the action of moving the blade 11 about a horizontally arranged longitudinal axis 22 substantially perpendicular to the blade, whereas tipping is the action of moving the blade about a horizontally arranged transverse axis 23 substantially parallel to the blade.
The blade control system 10 includes a solenoid operated directional control valve 24, a solenoid operated fluid regeneration valve 25, and a solenoid operated selector valve 26 that are conventionally actuated by electric signals. The directional control valve 24 is connected to a pump 27 and a tank 28 and has a pair of control ports 29,30. The directional control valve is shown in a neutral position and is movable in opposite directions to first and second variable operative positions. The directional control valve is this embodiment is actuated, for example, by electric signals received from a signal generator 31 in response to appropriate movement of a lever 32.
The fluid regeneration valve 25 is a two-position valve and is connected to the control ports 29,30 of the directional control valve. The fluid regeneration valve 25 has a cylinder port 33 and a valve port 34 with the cylinder port 33 being connected to the head end chamber 21 of the left cylinder 18. The regeneration valve 25 is normally biased to an operative position shown and is movable leftward to another operative position. In this embodiment, the fluid regeneration valve is moved leftward in response to receiving an electric signal, for example, from a push button 35 mounted on the control lever 32.
The selector valve 26 is connected to the valve port 34 of the regeneration valve 25 and has a cylinder port 36 connected to the rod end chamber 20 of the hydraulic cylinder 18, and another pair of cylinder ports 37,38 connected to the rod end and head end chambers 20,21 respectively of the hydraulic cylinder 19. The selector valve is a three position valve and is spring biased to the position shown. The selector valve is movable in a opposite directions from the position shown to two operative positions. The selector valve 26 can be shifted in any conventional manner independently of or in combination with movement of the lever 32.
The hydraulic cylinder 18 includes a piston 44 separating the head end and rod end chambers 21,20 with the piston having a circular area 46 defining one end of the head end chamber and an annular area 47 defining one end of the rod end chamber 20. Similarly, the hydraulic cylinder 19 has a piston 48 separating the head and rod end chambers with the piston having a circular area 49 defining one end of the head end chamber 21 and a circular area 50 defining one end of the rod end chamber 20. In this embodiment, the annular area 47 of the piston 44 is equal to the circular area 49 of the piston 48 and the circular area 46 of the piston 44 is larger than the circular area 49 of the piston 48.
In this embodiment, the directional control valve 24, regeneration valve 25 and selector valve 26 are described as solenoid operated valves actuated by electric signals. However, the invention is not limited to this specific form of the valves and each of them may be formed as a pilot operated valve actuated by a pilot signal generated by a proportional valve which is actuated by an electrical signal or a manually controlled pilot valve.
Industrial Applicability
In use with the selector valve 26 moved to its rightward operative position, the operator can obtain two stage regeneration for rapid extension of the hydraulic cylinders 18,19 to tilt the blade 11 forwardly by depressing the push button 35 to actuate the fluid regeneration valve 25 to its leftward operative position while moving the control lever 32 rightward, for example, to actuate the directional control valve 24 to its rightward operative position. With the valves 24,25,26 in the above noted position, pressurized fluid from the pump 27 is directed to the head end chamber 21 of the hydraulic cylinder 18. The hydraulic cylinder 18 functions as a master cylinder with the fluid expelled from the rod end chamber 20 being directed through the selector valve to the head end chamber 21 of the hydraulic cylinder 19 which functions as a slave cylinder. This provides the first stage of fluid regeneration the cylinders are extended at a rate about 2-3 times faster than if the pump flow was divided between the head end chambers of both cylinders. In this embodiment, since the annular area 47 of the piston 44 is equal to the circular end 49 of the piston 48, both cylinders will extend at identical speeds.
The second stage fluid regeneration is established by combining the fluid expelled from the rod end chamber 20 of the hydraulic cylinder 19 with the fluid passing through the regeneration valve 25 from the pump 27 to the head end chamber 21 of the hydraulic cylinder 18. Combining the fluid expelled from the rod end chamber 20 with the fluid directed to the head end chamber 21 of the hydraulic cylinder 18 causes the extension speed of the hydraulic cylinders to be increased by another 2-3 times resulting in a cylinder being extended at a rate of about 4-6 times faster than if the pump flow was divided between the head end chambers of both cylinders.
A slower, forward tipping mode is established by leaving the regeneration valve 25 in the position shown, moving the selector valve 26 rightward to its operative position and moving the directional control valve 24 rightward to communicate pressurized fluid from the pump 27 to the head end chamber 21 of the hydraulic cylinder 18. The fluid expelled from the rod end chamber 20 passes through the selector valve 26 to the head end chamber 21 of the hydraulic cylinder 19. However, in this mode, the fluid exhausted from the rod end chamber 20 of the hydraulic cylinder 19 is returned to the tank so that the second stage fluid regeneration feature is negated.
Rearward tipping of the blade is accomplished by moving the directional control valve 24 leftward while the selector valve 26 is in its rightward position and the regeneration valve is in the position shown. With the valves in these positions pressurized fluid from the pump passes through the directional control valve, the fluid regeneration valve 25 and through the selector valve 26 to the rod end chamber 20 of the hydraulic cylinder 19. Fluid expelled from the head end chamber 21 of the hydraulic cylinder 19 passes through the selector valve to the rod end chamber 20 of the hydraulic cylinder 18. The fluid expelled from the head end chamber 21 of the hydraulic cylinder 18 is vented to the tank 28. With the circular area 49 of the piston 48 being equal to the annular area 47 of the piston 44, both cylinders will retract at the same speed.
Dual cylinder tilting of the blade is accomplished by actuating the directional control valve 24 with the fluid regeneration valve 25 and the selector valve 26 in the positions shown. Single cylinder tilting of the blade is accomplished by actuating the directional control valve 24 with the regeneration valve 25 in the position shown and the selector valve 26 shifted to its leftward operative position.
Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.
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A blade control system includes a directional control valve, a fluid regeneration valve and a selector valve for selectively controlling fluid flow between a pump and first and second hydraulic cylinders and between the cylinders. With the valves positioned at preselected operative positions, pressurized fluid from the pump is directed to the head end chamber of the first cylinder, fluid expelled from the rod end chamber of the first cylinder is diverted to the head end chamber of the second cylinder, and fluid expelled from the rod end chamber of the second cylinder is combined with the fluid being directed to the head end chamber of the first cylinders to provide two stages of fluid regeneration for increasing the extension speed of the cylinder.
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BACKGROUND OF THE INVENTION
It is known that certain polysalt compositions which are composed of oppositely charged wet or dry strengthening agents for paper and an ionization suppressor provide paper of improved strength when added to beater pulp. A variety of these compositions and methods for the manufacture of strengthened paper therewith is disclosed in Economou U.S. Pat. Nos. 3,660,338 and 3,677,888.
FIELD OF THE INVENTION
The present invention relates to a novel water-soluble amphoteric polysalt useful as strengthening agent in the manufacture of paper. The invention includes the polysalt itself, paper having a content thereof, compositions of the polysalt with an ionization suppressor, and processes for the manufacture of paper of improved strength resulting from a content of the polysalt.
DESCRIPTION OF THE PRIOR ART
U.S. Pat. No. 3,660,338 discloses that a normally liquid water-insoluble polysalt coacervate, wherein one of the component polymers is only weakly ionic, is water-soluble when it contains a sufficient amount of an ionization suppressor. The compositions of the patent are strengthening agents useful as beater additives in the manufacture of paper.
U.S. Pat. No. 3,677,888 discloses that when an aqueous solution of the polysalt-ionization suppressor composition of the patent is added to a papermaking fibrous suspension, the polysalt is precipitated out of solution as colloidal droplets. The patent further discloses that the droplets are substantively adsorbed by the fibers while the fibers are in aqueous suspension and bind the fibers together when the fibrous suspension is further processed into paper. The result is paper of improved strength.
SUMMARY OF THE INVENTION
The discovery has now been made that the polysalt composed of an acrylamide-acrylic acid copolymer containing a small proportion of styrene units and a water-soluble cationic polymer having a molecular weight in excess of about 1,000 (as more particularly hereinafter described) is an effective strengthening agent for paper. I have also found that this polysalt, when colloidally dispersed in moderately acid and even substantially neutral aqueous medium, is substantive to cellulose papermaking fibers suspended in the medium and that these colloidal droplets or particles are strongly adsorbed by the cellulose fibers even though the aqueous medium has a high dissolved or dispersed content of black liquor solids and a high content of dissolved sulfate ions. I have further found that a mixture of a major proportion of the anionic component and a minor proportion of the cationic component in water is solubilized by an added acidic ionization suppressor and that the resulting solution releases its polysalt content in colloidal (ionic) state when the pH of the solution is raised to a value between about 4 and 7.
I have finally found that the invention permits the manufacture of paper possessing good dry strength (and if desired, both wet and dry strength) without need for alum at a nearly neutral pH from a pulp which has a substantial content of black liquor solids.
More in detail, according to the present invention the anionic component of the polysalt is a vinyl polymer which consists essentially of acrylamide, styrene and acrylic acid units (or their equivalents) in such proportion within the molar range of 94 - 65 : 5 - 15 : 1 - 20 (totalling 100%), that the polymer does not dissolve in water but disperses in water (which may be hot) when gently agitated therewith, forming a stable latex-like colloidal dispersion. Suitable polymers can be made by emulsion copolymerization of acrylamide with styrene in the range of about 95 : 5 to 85 : 15, followed by hydrolysis of part of the acrylamide substituents to provide about 1 to 20 mol percent of acrylic acid linkages. The term "acrylic acid linkages" includes those linkages in soluble salt form (i.e., as sodium salt form), as well as in acid form.
The styrene content of the anionic component of the polysalt is critical. I have found that the styrene substituents augment the driving force of the cationic substituents and permit paper of high dry strength (and if desired, wet strength) to be manufactured from pulps which contain a high concentration of black liquor soap. When less than about 5 mol percent of styrene units are present in the anionic polymer, use of the polysalt provides no significant economic advantage. When more than about 15 mol percent of these substituents are present in the anionic component, the polysalt decreases in its strengthening properties since an increase in the content of styrene units in the anionic polymer is generally at the expense of the amide substituents therein. It is the amide substituents which provide most of the strengthening properties of the polysalt.
The anionic polymers used in the present invention can contain linkages other than those disclosed in the present application provided that those other linkages are of such kind and are present in such small proportion as not to change the essential character of the polymer.
Thus, the polymer can contain small proportions of methacrylamide, N-diethylacrylamide, vinylphthalimide and maleamide linkages; p-chorostyrene, p-vinyltoluene, p-chloromethylstyrene, 2-vinylnapthalene and acrylonitrile linkages; and maleic acid, vinylbenzoic, and acrylic acid linkages.
The cationic component of the polysalt can be any water-soluble polyamine which has a molecular weight in excess of about 1,000, as the cationic molecule must be large enough to bind at least several of the anionic molecules together thereby ensuring that all the anionic macromolecules are formed into colloidal complex state when the polysalt-ionization suppressor solution is added to the pulp, and to drive on to the fibers as high as practicable a proportion of the polyamine.
The particular polyamine (or mixture of polyamines) to be used in any instance is not critical as the polyamine does not interfere with the substantivity imparted by the styrene units. However, I prefer to use a cationic polyamino water-Soluble dry- (or dry- and wet-) strenthening agent because these agents, which have molecular weights in excess of 1,000, possess adequate molecular size and cationicity, and in addition make their own contribution to the strength of the paper product. The cationic strengthening agent may be non-thermosetting or thermosetting, and in the latter event the paper product must be heated to thermosetting temperature (190° - 250° F.) to obtain the full benefit thereof.
The cationic strengthening agent can be the non-thermosetting water-soluble polyamidopolyamine-epichlorohydrin condensate of U.S. Pat. No. 3,329,657; polyvinylimidazoline; poly-N-(2-aminoethyl)acrylamide; polyvinylpyridine; and polymerized vinylmethylpyridinium chloride; other water-soluble vinyl polymers containing quaternary ammonium substituents including the 90 : 10 molar ratio acrylamide:diallyldimethyl ammonium chloride copolymers (U.S. Pat. Nos. 2,884,057 and 2,884,058); the polymers composed of acrylamide and vinylamine linkages of U.S. Pat. No. 2,890,978; the non-thermosetting amine-epichlorohydrin dry strength resins of U.S. Pat. Nos. 3,258,393 and 3,567,659; cationic starch; and the water-soluble salts of deactylated chitin. All of these have molecular weights in excess of 1,000. If desired, these polymers can beneficially carry a small proportion of styrene units in the range of 5 - 15 mol percent.
The anionic and cationic components are present in such ratio that a polysalt composed of these two polymers is soluble in water at a pH below 3, but insoluble in water at a pH in the mildly acidic to neutral pH range of 4 to 7. Such polysalts are generally composed of anionic and cationic components in weight ratio between about 9 : 1 and 1 : 1, i.e., in a charge equivalent ratio of about 1.25 : 1 to 0.5 : 1. I have found that this solubility requirement ensures that when a 1 - 10% by weight solution of the polysalt-ionization suppressor complex of the present invention (which generally has a pH below 2) is added to a large volume of water having a pH in the range of 4 to 7, the polysalt separates as an insoluble phase consisting of discrete colloidal particles which are neutral or ionic, and which are substantively adsorbed by the fibers.
It has not been found possible to develop a general rule which will permit predetermination of the ratio of the number of the anionic substituents in the polysalt of the present invention to the number of cationic substituents needed for formation of compositions of the present invention. The ratio varies from instance to instance, and is affected by such independent variables as the amount and the degree of ionization of the anionic substituents (e.g., carboxyl as compared with sulfo substituents); the charge of the cationic substituents (e.g., amine as compared with quaternary ammonium substituents); the number and kind of hydrophobic and hydrophilic substituents present; and the respective molecular weights of the anionic and cationic polymers. However, in any instance a suitable ratio is easily found by laboratory trial. One method is to add a 10% aqueous solution of a suitable cationic polymer slowly to a 10% aqueous solution of a suitable anionic polymer, the pH of the solution being maintained at 5.5. The correct ratio is found when an insoluble colloidal precipitate occurs. When the pH is adjusted to 2 or less with a strong acid, a clear solution results from which the polysalt colloid precipitates when the solution is added to mildly acidic beater pulp. If desired, the proportion of the cationic component can be increased somewhat, and this often improves the dry strengthening properties of the polysalt.
According to another method, a suitable ratio can be found by preparing 10% by weight aqueous solutions of the anionic and cationic components in various ratios at pH 4 to 7 and then adding a strong water-soluble acid. Those ratios are suitable which provide polysalts which are insoluble in the pH range of 4 to 7 but which dissolve at a lower pH, preferably below pH 3, and which form a colloid when the pH of the solution is raised to 4 - 7. Formation of the colloid can be seen by filtering a sample of the papermaking suspension to be treated (to remove all solids therefrom), adding sufficient of the polysalt-ionization suppressor solution to provide about 0.001% by weight of the polysalt, and adjusting the pH to 4 - 7. Formation of a colloidal phase (visible by Tyndall effect) shows that the anionic and cationic components are present in proper ratio.
In practice, the polysalt-ionization complex is prepared by mixing 10% - 20% aqueous solutions of the anionic and cationic components (in previously ascertained desirable ratio). The polysalt thus formed does not dissolve, but forms a supernatant layer. A sufficient amount of a strong water-soluble acid is then added to cause the two phases to dissolve. A suitable amount of acid has been added when the supernatant layer dissolves and remains soluble when the resulting solution is diluted with water to 0.5% - 1% polymer solids content. The pH of the latter solution usually is about 2.5 - 3.0.
If preferred, the ionization suppressor can be added to the cationic component, in which event the anionic component forms a soluble polysalt directly.
Suitable strong water-soluble acids which are satisfactory for use as ionization suppressors include benzenesulfonic, hydrochloric, sulfuric, phosphoric, nitric, chloroacetic, bromoacetic, trichloroacetic acids and other similar monomeric acids which have a pH of less than 3 and which are compatible with the polysalt (i.e., which do not form a precipitate therewith). Volatile acids (i.e., acids which are steam-distillable) such as hydrochloric acid are preferred when paper having an alkaline pH is desired. Normally solid acids (e.g., 1- and 2- naphthalene sulfonic acids) can be used when it is desired to prepare the components as a particulate free-flowing blend.
The polysalt of the present invention may be thermosetting or non-thermosetting. It possesses wet strengthening properties (in addition to dry strengthening properties) when at least one of its components carries a sufficient number of reactive substituents to render the component thermosetting. Substituents which impart thermosetting properties are methylol substituents (introduced by formaldehyde), --CHOHCHO substituents (introduced by glyoxal), and epoxy ##STR1## substituents (introduced by epichlorhydrin). Thus, for example, the anionic component may be a vinylamide linkage carrying a methylol or glyoxal substituent, or the cationic component may be a polyalkylenepolyamine linkage carrying a thermosetting substituent. Polymers carrying these substituents are disclosed in U.S. Pat. Nos. 2,345,543 and 2,986,489 (methylol substituents); 2,595,935 and 2,926,154 (epoxy substituents); and 3,556,932 (glyoxal substituents). Alternatively, the polymers can be those which possess wet strengthening properties but which possess no identifiable wet strengthening substituents, for example polyethylenimine.
The polysalt possesses dry strengthening properties (without possessing wet strengthening properties) when neither of the components carries thermosetting substituents.
The present invention also includes a particulate free-flowing blend (i.e., physical mixture) of the anionic component, the cationic component and the ionization suppressor all in appropriate proportions. A polysalt according to the present invention forms when the blend is dissolved in water.
The polysalt-ionization suppressor compositions of the present invention are used in papermaking by distributing them uniformly through the papermaking stock into paper. For convenience in metering, they are preferably diluted to 1% - 5% solids in water having an appropriately low pH, and are added as close to the fourdrinier wire as is practical, for example, at the fan pump or head box. The compositions can be successfully added to furnishes which contain alum in normal amount and which thus have a pH in the range of 4 - 6. This secures the full benefit of the alum present and incorporates alum into the paper, and when one or both of the polymers carries aldehyde thermosetting substituents, best wet strengthening is obtained.
The compositions can also be successfully added to substantially neutral pulps (i.e., pulps having a pH in the range of 6 or 7 or slightly higher), permitting the production of neutral or alkaline paper.
The polysalt is added in suitable amount to provide the desired amount of strengthening. The polysalt is effective for the purpose when present in the range of 0.1% - 3% (polymer solids based on the dry weight of the fibers). The wet web is dried as is customary (for example 1/4 to 3 minutes on rolls having a surface temperature between about 190° F. and 250° F.) This is sufficient to develop the wet-strengthening properties of polymers which contain thermosetting components. The polysalt can also be applied by size press or it can be sprayed on the wet web.
The polysalt is also useful as flocculant in the purification of water having a suspended content of mineral and organic matter or fiber fines, such as in a saveall.
The invention is more fully described in the examples. These examples are preferred embodiments of the invention, and should not be construed as limitations thereon.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
EXAMPLE 1
The following illustrates the preparation and certain of the properties of a series of polysalt-ionization inhibitor compositions, according to the present invention.
The polysalt in each instance is prepared by mixing a 10% by weight solution of a cationic polymer (as described in the table below, adjusted to pH 2) with an equal amount of a 10% by weight solution of a vinyl anionic polymer composed of acrylamide, styrene, and acrylic acid linkages in about 80 : 11 : 9 molar ratio, also adjusted to pH 2. Opalescent solutions form.
A sample of each solution is held at 70° F. for 30 days to determine its storage-stability, and a sample is diluted to about 0.001% solids with water at pH 6 to determine whether the solution develops a polysalt colloid when so diluted.
Results are as follows.
__________________________________________________________________________Composition.sup.1 Stability.sup.2Soln. Ionizat. On Dilution AfterNo. Cationic Polymer.sup.3 Inhibitor To 0.001%.sup.4 1 Mo.__________________________________________________________________________1 Cationic starch HCl Forms colloid. No change2 Polyvinylimidazoline H.sub.2 SO.sub.4 " "3 Polyethylenimine HCl " "4 Adipic acid - DETA.sup.5 " " "5 AM-DADMA (glyoxalated " " " thermosetting).sup.66 Urea-TETA-CH.sub.2 O.sup.7 " " "__________________________________________________________________________ .sup.1 Contains anionic and cationic polymers in 1 : 1 weight ratio. The cationic polymers have molecular weights in excess of 1,000. .sup.2 Of 10% solution of polysalt and ionization inhibitor having a pH below 3. .sup.3 DETA = diethylenetriamine; TETA = triethylenetetramine; AM = acrylamide; DADMA = diallyldimethylammonium chloride. 4On dilution to 0.001% polymer solids with water at pH 6. .sup.5 For preparation see U.S. Pat. No. 2,926,154. .sup.6 For preparation see Williams et al. U.S. Pat. No. 3,556,932. .sup.7 For preparation see U.S. Pat. No. 2,926,154.
EXAMPLE 2
The syrupy polymer supernatant layer obtained by mixing one volume of the 10% aqueous anionic polymer solution of Example 1 with one volume of a 10% aqueous polyethylenimine solution is drawn off. A portion is used to cement two aluminum panels together under 1,000 lb./in. 2 pressure and 200° C. for 10 minutes. On cooling, the panels are strongly bonded together.
EXAMPLE 3
The following illustrates the dry strength imparted by certain polysalts of the present invention in the manufacture of paper from a pulp of unbleached fibers in an aqueous medium containing a large amount of black liquor.
A series of polysalt-ionization suppressor solutions is prepared by the general method of Example 1. The anionic polymer is composed of acrylamide, styrene and acrylic acid units in 75.8 : 20.2 : 4 molar ratio respectively. The cationic polymers are stated in the table below. In each instance a 10% solution of the anionic polymer is mixed with sufficient of a 10% solution of the cationic polymer to provide a polysalt containing the anionic and cationic polymers in 4 : 1 weight ratio, equivalent to a roughly 1 : 1 ratio in terms of ionic functionalities, followed by enough concentrated hydrochloric acid to adjust the pH to 2.
A stock papermaking suspension is prepared by slurrying well-beaten unbleached kraft fibers (known as "Fortopulp") in water containing 3% of black liquor solids and 1% alum and diluting to a consistency of 0.7% (percentages based on the dry weight of the fibers). The resulting suspension has a pH of 5.7.
In each instance an aliquot of the suspension is taken and to this is added sufficient of one of the polysalt-ionization suppressor solutions (diluted to 1% solids with water) in amount shown in the table below. Colloid formation occurs. The suspension is gently stirred for 30 seconds to permit the fibers to adsorb polysalt colloid particles, while the pH of the suspension is adjusted to 5.7.
In each instance addition of the polysalt solution causes the freeness of the pulp to increase perceptibly (by 3% - 4%).
The fibers are formed into a wet web on a laboratory handsheet machine at a basis weight of 70 lb. per 25 × 40 inches/500 ream. The wet web is dried for 2 minutes on a laboratory drum drier having a surface temperature of 240° F. The dry strength of the resulting paper is determined by the Mullen burst test and by the internal bond test (delamination in the "z" direction).
Results are as follows.
__________________________________________________________________________ Burst % Polysalt %Run No. Cationic Polymer Added.sup.a Lb./in..sup.2 Increase Ft.-lb./in..sup.2__________________________________________________________________________Control None -- 53.0 -- 0.0581 Isophthalic - DETA - epi.sup.b 0.2 61.8 16.6 0.0852 " 0.4 71.3 34.6 0.1053 Adipic - TETA - epi.sup.c 0.2 64.3 21.3 0.0934 " 0.4 71.8 35.5 0.1045 Adipic - DETA - epi.sup.d 0.2 66.2 25.0 0.0886 " 0.4 69.0 30.0 0.103__________________________________________________________________________ .sup.a Based on dry weight of fibers. .sup.b Isophthalic acid-diethylenetriamine-epichlorohydrin thermosetting wet- and dry-strength polymer of U.S. Pat. No. 3,733,290 .sup.c Adipic acid-tetraethylenetetramine-epichlorohydrin non-thermosetting dry-strength polymer of U.S. Pat. No. 3,329,657. .sup.d Adipic acid-diethylenetriamine-epichlorohydrin thermosetting wet- and dry-strength polymer of U.S. Pat. No. 2,926,154.
EXAMPLE 4
The following illustrates the improvement in drainage and in dry strength which is effected by polysalts which differ only in the carboxyl content of the anionic component.
The anionic polymer is prepared by subjecting an 88.2 : 11.8 molar ratio acrylamide : styrene copolymer to hydrolysis to the extents shown in the table below, thereby converting acrylamide units to acrylic acid units to the extents shown. The procedure of Example 3 is then repeated, the cationic component of the polysalt being the non-thermosetting adipic acid-triethylenetetramine-epichlorohydrin polymer of U.S. Pat. No. 3,329,657. The polysalt is composed of the anionic and cationic components in the average weight ratio of 3 : 1.
Addition of the polysalt causes a 3% - 4% improvement in the drainage rate. Other results are as follows.
______________________________________ Paper Strength Cat. Polymer InternalRun Molar Ratio Burst BondNo. AM:St:AA % Increase % Increase______________________________________0.2% Polymer Added on Wt. of Fibers1a 85.8:11.8:2.4 4.5 212a 82.7:11.8:5.5 6.6 243a 80.3:11.8:7.9 8.5 254a 78.0:11.8:10.2 10.0 260.4% Polymer Added on Wt. of Fibers1b 85.8:11.8:2.4 12.0 412b 82.7:11.8:5.5 13.9 463b 80.3:11.8:7.9 15.0 444b 78.0:11.8:10:2 15.0 45______________________________________
EXAMPLE 5
The following illustrates another method for determining the optimum proportion of acid substituents in the anionic polymer and for determining the optimum anionic:cationic polymer ratio. It has been found that usually the effectiveness of a polysalt in promoting the freeness of a pulp is a measure of its effectiveness as a paper strengthening agent.
The general method of Example 3 is followed except that the pulp is adjusted to pH 5.5 after addition of the polysalt solution and the composition of the polysalt is as shown in the table below. In each instance the cationic component of the polysalt is the non-thermosetting adipic acid:triethylenetetramine-epichlorohydrin condensate of U.S. Pat. No. 3,329,657.
Results are as follows.
______________________________________ Cat. Polymer Wt. Ratio FreenessRun Molar Ratio.sup.a Anionic IncreaseNo. AM:St:AA Cationic Ml..sup.c______________________________________1 50/50 252 60/40 303 86.1:11.8:2.1 70/30 404 80/20 405 90/10 406 50/50 307 60/40 358 82.5:11.8:5.7 70/30 409 80/20 4510 90/10 4511 50/50 2012 60/40 2513 77.1:11.8:11.1 70/30 2814 80/20 3015 90/10 25______________________________________ .sup.a Molar ratio of acrylamide, styrene and acrylic acid units in cationic polymer. .sup.b Weight ratio of anionic polymer to cationic polymer in polysalt. .sup.c Increase in freeness (Canadian standard) of pulp over respective controls (600-650 ml.) caused by addition of polysalt-ionization inhibito solution.
EXAMPLE 6
The following illustrates additional polysalts within the present invention and the manufacture of strengthened paper therewith.
The procedure of Example 3 is repeated except that the pulp contains 200 parts of dissolved sulfate ions per million parts by weight of solution, the pulp is adjusted to pH 5.5 after addition of the polysalt, and the polysalts are the interaction product of 1 part by weight of an anionic polymer composed of acrylamide, styrene and acrylic acid units in 80:11:9 molar ratio with the amount of the cationic polymer shown in the table below, and in each instance the amount of polysalt added is 0.4% of the dry weight of the fibers.
Results are as follows.
__________________________________________________________________________ Paper StrengthCationic Polymer InternalRun Wt. Charge Burst BondNo. Name %.sup.a %.sup.b Lb./in..sup.2 Ft.lb./in..sup.2__________________________________________________________________________Blank None 95.4 0.0811 400 50 107.1 0.1132 Cationic starch 200 26 104.5 0.1063 100 13 110.9 0.1094 20 167 105.9 0.127 imidazoline.sup.cPoly-2-vinyl5 11 93 113.3 0.112__________________________________________________________________________ .sup.a Weight of cationic polymer on weight of anionic polymer. .sup.b Number of cationic groups in cationic polymer per 100 anionic groups in anionic polymer. .sup.c Contains 10 mol percent of methyl methacrylate units.
EXAMPLE 7
The following illustrates the simultaneous improvement in strength and in freeness imparted by a preferred polymer of the present invention.
The procedure of Example 3 is repeated except that the polysalt is a 4 : 1 by weight mixture of an 80 : 10 : 10 molar ratio acrylamide : styrene : acrylic acid copolymer and the non-thermosetting cationic polymer is made by substantially completely reacting 0.3 mol of epichlorohydrin with a 1 : 1 molar ratio adipic acid : triethylenetetramine condensate.
Results are as follows.
______________________________________Run % Polysalt Freeness BurstNo. Added ml. % Incr.______________________________________Control None 500 --1 0.2 521.5 11.52 0.4 540.0 15.0______________________________________
EXAMPLE 8
The following illustrates performance of the process of the present invention on a commercial scale.
The process is applied in a modern paper mill making paper of 100 lb. basis weight per 25 × 40 inches/500 ream from a furnish of unbleached kraft pulp containing 3% black liquor solids and 1% alum and having a pH of 5.5. The paper has a dry tensile strength of about 78 lb./inch, and is regarded as the control paper.
There is then added at the fan pump 0.3% (polymer solids based on the dry weight of the fibers) of a polysalt-ionization inhibitor composition wherein the polysalt is 80% by weight of an 82.1:10.0:7.9 molar ratio acrylamide : styrene : acrylic acid, and 20% by weight the water-soluble non-thermosetting cationic polymer formed by substantially completely reacting 0.3 mol of epichlorohydrin with a 1 : 1 molar ratio adipic acid : triethylenetetramine condensation product, and contains hydrochloric acid in sufficient amount to give the solution a pH of 2. The composition is added to the furnish as a 1% aqueous solution, and causes some foam.
There is then added at the fan pump (in addition to the polysalt) a non-ionic silicone anti-foaming agent (GE-72) as needed to suppress the foam. This causes a substantial increase in the drainage rate.
The dry strength of the paper is determined after each addition. Results are as follows.
______________________________________Test Additives Paper StrengthTest Polysalt Antifoam Found.sup.a % Incr..sup.b______________________________________Control None None 78.0 --A 0.3%.sup.c None 85.3 9.4B 0.3% As needed 91.2 14.7 to suppress foam______________________________________ .sup.a Lb./inch. .sup.b Based on control. .sup.c Weight of polysalt in polysalt-ionization complex based on dry weight of the fibers.
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The polysalt which consists essentially of a specified acrylamide-styrene-acrylic acid interpolymer and a water-soluble cationic polyamine having a molecular weight in excess of 1,000 (the molar ratio of the anionic to the cationic substituents in the anionic polymer and in the polyamine being within specified ranges) is an efficient strengthening agent for paper. Compositions of the polysalts and an ionization suppressor for the anionic components therein can be employed as beater additives in paper manufacture at a mildly acid pH leading to a nearly neutral paper having excellent dry strength and, if desired, wet strength.
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RELATED APPLICATIONS
The present invention was first described in a notarized Official Record of Invention on Apr. 3, 2009, that is on file at the offices of Montgomery Patent and Design, LLC, the entire disclosures of which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates generally to trash disposal facilities, and in particular, to a dumpster enclosure adapted for quick access via a conventional waste collection truck forklift assembly.
BACKGROUND OF THE INVENTION
In many commercial and residential settings, trash collection is consolidated via conventional dumpsters prior to attendance by a local waste collection agency. Due to associated odors and other health concerns, dumpsters are generally located outdoors. The outdoor location further facilitates easy access by waste collection vehicles for lifting and emptying. However, trash receptacles such as dumpsters are generally considered to be unsightly and also to pose various health and safety hazards. As a result, most such receptacles are housed inside a fencing assembly or other enclosure in order to provide a visual screening and physical barrier between the waste materials and people in the vicinity.
While such enclosures indubitably serve their purposes, enclosure of dumpsters inhibits the efficiency with which waste collection vehicles and the like are able to access the dumpsters for emptying. General practice is for a driver or operator of such a vehicle to park and exit the vehicle, open the dumpster enclosure, lift and empty the dumpster, replace the dumpster, and again exit the vehicle to close and secure the enclosure. While individual dumpsters are often only accessed on a periodic basis, repeated performance of these actions during a daily route adds a significant amount of time and physical exertion to the routine of the operator.
Various attempts have been made to provide waste receptacle enclosures. Examples of these attempts can be seen by reference to several U.S. patents. U.S. Pat. No. 3,924,913, issued in the name of Cooper, describes a garbage can enclosure device which provides a screened enclosure for conventional outdoor trash cans.
U.S. Pat. No. 6,978,576, issued in the name of Shirk, describes a gate assembly which provides a durable and shock absorbent gated enclosure for a conventional dumpster.
Additionally, ornamental designs for a waste receptacle enclosure exist, particularly U.S. Pat. Nos. D 402,375 and D 549,917. However, none of these designs are similar to the present invention.
While these devices fulfill their respective, particular objectives, each of these references suffer from one (1) or more of the aforementioned disadvantages. Many existing enclosures are difficult and time consuming to access for an operator of a conventional waste collection vehicle. Also, many existing enclosures require a user to exit a vehicle in order to selectively access the enclosed structure. Furthermore, many existing enclosures such as conventional fencing assemblies do not provide a desirable level of aesthetic screening to an enclosed waste receptacle. Accordingly, there exists a need for a dumpster enclosure without the disadvantages as described above. The development of the present invention substantially departs from the conventional solutions and in doing so fulfills this need.
SUMMARY OF THE INVENTION
In view of the foregoing references, the inventor recognized the aforementioned inherent problems and observed that there is a need for an enclosure suitable for outdoor use with a conventional dumpster which provides features of aesthetic screening and ease of access via a conventional existing waste collection vehicle. Thus, the object of the present invention is to solve the aforementioned disadvantages and provide for this need.
To achieve the above objectives, it is an object of the present invention to provide a dumpster screen which conceals an existing conventional trash receptacle.
Another object of the present invention is to allow a conventional trash receptacle with front loading sleeves to be accessed for loading and emptying via a conventional trash collection vehicle.
Yet still another object of the present invention is to enclose a trash receptacle on four (4) sides. The apparatus comprises a rectangular structure further comprised of a plurality of pipe frame sections, a gate portion, a moveable rod, and a plurality of screening sections.
Yet still another object of the present invention is to provide a gate on a front portion which can be lowered and locked via downward force provided by loading arms of an existing trash collection vehicle. This is accomplished via a movable rod which is attached at an upper location to inner side portions between front side posts of the frame.
Yet still another object of the present invention is to automatically return to an original concealing position after a trash collection vehicle removes and empties a contained trash receptacle.
Yet still another object of the present invention is to allow vertical motioning of the movable rod via “U”-shaped channels positioned vertically to the front posts of the frame. The posts further comprises integral pulley assemblies including steel cables, pulley axles, counter weights, pulley fasteners, and the like which provide a means for support the movable rod and returning it to an initial position upon removal of a trash collection vehicle.
Yet still another object of the present invention is to provide selectable decorative screening of a contained trash receptacle via the screening portions. The screening portions are constructed of a durable weatherproof material for outdoor use.
Yet still another object of the present invention is to attach the apparatus to a level ground surface via a plurality of rectangular feet which support the apparatus vertically.
Yet still another object of the present invention is to provide a method of utilizing the device that provides a unique means of positioning the structure around an existing trash receptacle in order to provide a concealing function, utilizing an existing trash collection vehicle with conventional loading arms in order to depress the movable rod for access to the contained receptacle, lifting and emptying the receptacle in a conventional manner, replacing the receptacle, and automatically returning the front gate to a closed position upon removal of the collection vehicle in order to return the apparatus to a concealing configuration without need for leaving the vehicle.
Further objects and advantages of the present invention will become apparent from a consideration of the drawings and ensuing description.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and features of the present invention will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which:
FIG. 1 is a perspective view of a dumpster screen 10 depicting a closed state, according to a preferred embodiment of the present invention;
FIG. 2 is a perspective view of the dumpster screen 10 depicting an open state, according to a preferred embodiment of the present invention;
FIG. 3 is a perspective view of the dumpster screen 10 depicting a frame 18 , according to a preferred embodiment of the present invention;
FIG. 4 is a front view of a gate 30 , according to a preferred embodiment of the present invention;
FIG. 5 is a side elevation view of the gate 30 , according to a preferred embodiment of the present invention;
FIG. 6 is a top view of a single post portion 32 of the gate 30 , according to a preferred embodiment of the present invention; and,
FIG. 7 is a front view of a side entrance 70 , according to a preferred embodiment of the present invention.
DESCRIPTIVE KEY
10 dumpster screen
15 trash receptacle
16 sleeve
18 frame
20 rear corner pipe
21 screen
22 tab
23 first rod
24 second rod
25 movable rod
26 third rod
27 side pipe
30 gate
31 channel
32 post
33 pulley
34 pulley access panel
35 cable
36 spring
37 spring access panel
38 first counter weight
39 second counter weight
40 diverter gate
50 first counter weight fastener
52 locking arm
60 foot
61 foot fastener
70 side entrance
71 elastic cord
72 cord spring
73 cord hook
80 first pivot
81 second pivot
82 spring attachment point
83 spring fixed point
90 pulley axle
91 pulley fastener
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The best mode for carrying out the invention is presented in terms of its preferred embodiment, herein depicted within FIGS. 1 through 7 . However, the invention is not limited to the described embodiment and a person skilled in the art will appreciate that many other embodiments of the invention are possible without deviating from the basic concept of the invention, and that any such work around will also fall under scope of this invention. It is envisioned that other styles and configurations of the present invention can be easily incorporated into the teachings of the present invention, and only one particular configuration shall be shown and described for purposes of clarity and disclosure and not by way of limitation of scope.
The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items.
The present invention describes a dumpster screen (herein described as the “apparatus”) 10 , which provides a means for concealing an existing conventional trash receptacle 15 , yet allowing said trash receptacle 15 to be accessed for loading and emptying thereof. Said apparatus 10 preferably utilized with conventional front end trash receptacles 15 which comprise a pair of front sleeves 16 , thereby allowing a conventional front loading garbage truck to utilize said sleeves 16 for conventional emptying. Other trash receptacles 15 may be utilized without limiting the functions of the apparatus 10 . Said apparatus 10 comprises a rectangular shape, thereby enclosing the trash receptacle 15 thereon four (4) sides. Said apparatus 10 also comprises a pair of rear corner pipes 20 , a plurality of screening 21 , a plurality of first rods 23 , a movable rod 25 , a pair of third pipes 26 , a pair of side pipes 27 , a gate portion 30 , a pair of pulleys 33 , a first counter weight 38 , a second counter weight 39 , and a side entrance 70 . Said apparatus 10 allows the areas around trash receptacle 15 to be contained for security and aesthetic reasons.
Referring now to FIG. 1 , a perspective view of the apparatus 10 depicting a closed state and FIG. 2 , a perspective view of the apparatus 10 depicting an open state, according to the preferred embodiment of the present invention, are disclosed. In use, the apparatus 10 is positioned on a level ground surface encompassing an existing trash receptacle 15 , thereby concealing said trash receptacle 15 . A gate 30 (also see FIG. 4 through 6 ) located on a front portion of the apparatus 10 is lowered and locked via a downward force provided by a pair of loading arms thereon the front loading garbage truck. The garbage truck then removes the trash receptacle 15 for emptying in a conventional manner. When finished the garbage truck replaces the trash receptacle 15 via the pair of loading arms 16 to its original position which also unlocks the gate 30 , thereby positioning the apparatus 10 to an original concealed position.
Referring now to FIG. 3 , a perspective view of the apparatus 10 depicting a frame 18 , according to the preferred embodiment of the present invention, is disclosed. The apparatus 10 is depicted without a plurality of screening 21 for illustration purposes only; it is known that screening 21 is to be incorporated into the final design for concealing of the trash receptacle 15 . The apparatus 10 comprises a rectangular frame 18 which also comprises a pair of rear corner pipes 20 , a plurality of first rods 23 , a pair of second rods 24 , a movable rod 25 , a pair of third rods 26 , a pair of posts 32 , and a plurality of feet 60 . A pair of tubular rear corner pipes 20 is positioned vertically at rear corners of the frame 18 . A tubular first rod 23 is horizontally positioned at a ninety degree (90°) angle from the rear corner pipes 20 at an upper and a lower location, thereby supporting said rear corner pipes 20 . The rear corner pipes 20 located at the rear corners of the apparatus 10 and the first rods 23 located perpendicular to said rear corner pipes 20 create a rear panel structure of the frame 18 . The length of the first rod 23 located between the pair of rear corner pipes 20 which are located at the rear portion of the apparatus 10 is wider than that of the trash receptacle 15 , thereby allowing said trash receptacle 15 to be located therein. The first rods 23 also provide a suspending means to screening 21 , thereby attaching said screening 21 thereto the first rods 23 (see herein below). The rear corner pipes 20 are fabricated from conventional steel piping preferably comprising a diameter of two (2) inches and comprising a height which is an appropriate dimension to conceal the trash receptacle 15 , yet other dimensions may be utilized without limiting the functions of the apparatus 10 . The first rods 23 and rear corner pipes 20 are fabricated from a steel material, yet other durable materials may be utilized without limiting the functions of the apparatus 10 .
A side portion of the frame 18 is created via positioning a pair of tubular second rods 24 at an upper and a lower position perpendicular to a rear corner pipe 20 . Distal end portions of the second rods 24 are attached to the rear corner pipe 20 with fastening means such as, but not limited to: welding, interference fitting, or the like. Proximal end portions of the second rods 24 are connected to a rectangular post 32 located parallel to the rear pipe 20 via a fastening means which is similar as abovementioned. Said post 32 is located at a front portion of the apparatus 10 and is an integral element of a gate 30 (see FIG. 4 through 6 ). The addition of the pair of second rods 24 to the rear corner pipe 20 and post 32 provides a side panel to the frame 18 and also provide a suspending means to screening 21 , thereby attaching said screening 21 thereto the second rods 24 (see herein below). The second rods 24 are appropriate dimensions to conceal the width of the trash receptacle 15 and are fabricated from steel, yet other materials may be utilized without limiting the functions of the apparatus 10 .
Another side portion of the frame 18 is created via positioning a pair of tubular third rods 26 at an upper and a lower position perpendicular from the other rear corner pipe 20 . The third rods 26 are then attached to a tubular side pipe 27 , thereby securing said third rods 26 in a horizontal position. Attached to an upper and lower opposite portion of the side pipe 27 are a pair of elastic cords 71 which are further attached to a rectangular post 32 , thereby creating a side entrance 70 (see FIG. 7 ). The side pipe 27 is located at an intermediate position between the rear corner pipe 20 and the post 32 . The third rods 26 and elastic cords 71 also provide a suspending means to screening 21 , thereby attaching said screening 21 thereto the third rods 26 (see herein below).
The post 32 is parallel to the opposite post 32 and rear corner pipe 20 . The posts 32 are separated at an appropriate width that which corresponds to the width of the first rods 23 via a tubular movable rod 25 and another first rod 23 . The movable rod 25 is positioned at an upper location between the posts 32 and provides an upward and downward motion of gate 30 (also see FIGS. 4 through 6 ) and an attachment means to screening 21 . The movable rod 25 is attached to inner side portions of the posts 32 via an internal pulley 33 (see FIG. 4 through 6 ). The first rod 23 is positioned at a lower position between the posts 32 and attached thereto with fastening means such as, but not limited to: welding, interference fitting, or the like, thereby creating a structurally sound frame 18 . The posts 32 are fabricated from conventional steel rectangular pipe with a diameter of five (5) inches, yet other materials and dimensions may be utilized without limiting the functions of the apparatus 10 . The movable rod 25 is fabricated from conventional steel pipe with a diameter of one-and-a-half (1½) inches, yet other materials and dimensions may be utilized without limiting the functions of the apparatus 10 .
The frame 18 is attached to a level ground surface via a plurality of rectangular feet 60 , thereby supporting the apparatus 10 vertically. The feet 60 are preferably attached via conventional welding techniques thereto a bottom distal portion of the rear corners pipes 20 , the side pipe 27 , and the posts 32 . Said feet 60 are then fastened to the ground surface therewith foot fasteners 61 which are comprised of conventional fasteners such as, but not limited to: bolts, stakes, or the like. The feet 60 are fabricated from steel, yet other materials may be utilized without limiting the functions of the apparatus 10 .
The frame 18 of the apparatus 10 comprises a plurality of screening 21 (also see FIGS. 1 , 2 , 4 , and 7 ) as abovementioned, thereby providing a concealing means to the trash receptacle 15 . Said screen 21 may be fabricated from a variety of outdoor weatherproof materials such as, but not limited to: wire mesh, nylon, canvas, or the like. The screening 21 is attached to the first rods 23 , the second rods 24 , the movable rod 25 , the third rods 26 , and the elastic cords 71 via a plurality of tabs 22 . Said tabs 22 are preferably attached to the screening via conventional sewing techniques at equidistant intervals and attached to an appropriate horizontal device 23 , 24 , 25 , 26 , 71 via fastening means such as, but not limited to: hook-and-loop fasteners, adhesive, sewing techniques, or the like. Said tabs 22 are fabricated from a material such as, but not limited to: canvas, plastic, metal, or the like. The screening 21 may also comprise indicia which may provide script or logos based upon a user's preference and may include images such as, but not limited to: sports names/logos, personal names, symbols, pictures, and the like to further customize and personalize the apparatus 10 further comprising a variety of colors and patterns.
Referring now to FIG. 4 , a front view of a gate 30 , according to the preferred embodiment of the present invention, is disclosed. The apparatus 10 comprises a gate 30 , thereby providing access to the trash receptacle 15 . The gate 30 comprises a pair of posts 32 as abovementioned thereon each front corners of the apparatus 10 . Each post 32 comprises a channel 31 , a of pulley 33 , a plurality of cable 35 , a spring 36 , a first counter weight 38 , a second counter weight 39 , a diverter gate 40 , and a locking arm 52 (also see FIGS. 5 and 6 ). Said gate 30 allows the garbage truck to lower its loading arms across the movable rod 25 and continue lowering until the trash receptacle 15 can be removed in a normal manner. After emptying, the trash receptacle 15 is replaced in the same normal manner and the gate 30 automatically returns to an original concealing position.
Referring now to FIG. 5 , a side view of the gate 30 and FIG. 6 , a top view of the gate 30 , according to the preferred embodiment of the present invention, are disclosed. A “U”-shaped channel 31 is positioned vertically to each post 32 and attached to a front portion of each said post 32 , thereby providing a means for the movable rod 25 to descend and rise. Said channel 31 is preferably a four (4) inch steel channel, yet other devices and materials may be incorporated without limiting the features of the apparatus 10 . Said channel 31 is attached to the post 31 via conventional welding techniques, yet other fastening means may be provided without limiting the functions of the apparatus 10 .
The gate 30 lowers and rises via a pair of circular pulleys 33 . A pulley 33 is located at an upper location internally within each post 32 and corresponding channel 31 . A steel cable 35 is wound around the pulley 33 and attached at a lower location to a spring 36 at a spring attachment point 82 , thereby allowing the spring 36 to retract to decrease the length of the cable 35 and extend to increase the length of the cable 35 . An opposite end portion of the spring 36 is fixed within the post 32 at a spring fixed point 83 . A distal portion of each cable 35 is attached to the movable rod 25 , thereby concurrently lowering or raising said movable rod 25 as the length of the cable 35 is increased or decreased, respectively. Each pulley 33 is attached to the post 32 via a pulley axle 90 fastened via conventional pulley fasteners 91 which allow said pulleys 33 to rotate freely in a conventional manner. Each post 32 comprises a pulley access panel 34 thereon a rear top portion and a spring access panel 37 thereon a rear lower portion, thereby providing access to the pulley 33 and spring 36 , respectively, for routine maintenance.
As the movable rod 25 is lowered from a downward force applied via the loading arms on the garbage truck the cable 35 is extended downwardly and the spring 36 is extended upwardly. The movable rod 25 travels further downward to come in contact with an “L”-shaped first counter weight 38 thereon each distal end portion, thereby causing said first counter weight 38 to pivot in a downward motion. Said first counter weight 38 is attached to an intermediate outer surface thereon the post 32 via first pivot 80 to a first counter weight fastener 50 such as, but not limited to: a shoulder bolt, a bushing and pin, a bracket, or the like. Said first counter weight 38 is positioned at an appropriate location which will allow for proper pivoting of said first counter weight 38 to enable the movable rod 25 to move beyond. The first counter weight 38 is an appropriate weight to allow for correct pivoting once contacted by the movable rod 25 . A rectangular locking arm 52 is positioned above the resting position of the first counter weight 38 , thereby impeding the upward motion of said first counter weight 38 . The locking arm 52 is preferably a steel device welded to the post 32 .
Once below the first counter weight 38 the movable rod 25 is locked into a downward position between said first counter weight 38 and a diverter gate 40 , thereby stopping the movement of the movable rod 25 and positioning the gate 30 in an open state (see FIG. 2 ). The diverter gate 40 is comprised of a rectangular steel plate slightly smaller than the dimensions of the channel 31 , thereby enabling insertion therein. In use, this is the moment when the loading arms thereon the garbage trucks are inserted into the first sleeves 16 thereon the trash receptacle 15 for conventional emptying. Once the trash receptacle 15 is placed back within the apparatus 10 the loading arms come in contact with the movable rod 25 , thereby allowing an “L”-shaped second counter weight 39 to pivot upwardly. This interaction also allows the internal diverter gate 40 to correspondingly rotate counterclockwise, thereby enabling the movable rod 25 to travel further downwardly and release itself from the diverter gate 40 further ascending the movable rod 25 to its original upward closed position (see FIG. 1 ). The second counter weight 39 is attached to a side portion of the channel 31 via a second pivot 81 which is comprised of conventional a shoulder bolt, a bushing and pin, a bracket, or the like, yet other fastening means may be utilized without utilizing the functions of the apparatus 10 . The second counter weight 39 and the diverter gate 40 pivot via a second pivot 81 , thereby attaching said second counter weight 39 and diverter gate 40 together and enabling a simultaneous counterclockwise rotation. The second pivot 81 preferably comprises a bolt and keyhole arrangement which would enable an attachment of the second counter weight 39 and the diverter gate 40 and provide the necessary synchronized pivoting means, yet other fastening and pivoting means may be utilized without limiting the functions of the apparatus 10 . The second counter weight 39 is an appropriate weight to allow for correct rotation thereof itself and the diverter gate 40 .
Referring now to FIG. 7 , a front view of a side entrance 70 , according to the preferred embodiment of the present invention, is disclosed. The apparatus 10 comprises a side entrance 70 , thereby enabling a person to access the trash receptacle 15 for filling in a conventional manner. The upper and lower horizontal portions of the side entrance 70 each comprises an elastic cord 71 , a pair of cord springs 72 , and a pair of cord hooks 73 . The tabs 22 attached to the screen 21 are further attached thereon each elastic cord 71 , thereby suspending said screen thereon. Cord springs 72 encompass each end portions of the elastic cords 71 which are further attached to corresponding cord hooks 73 , thereby providing a fastening means to the post 32 and side pipe 27 . The cord springs 72 provide a tensioning means to the elastic cord 71 , thereby securing the screen 21 thereon. The cord hooks 73 provide an attaching means to the corresponding post 32 and side pipe 27 . The cord hook 73 may attached to the post 32 and side pipe 27 via means such as, but not limited to: engaging an aperture, engaging an eye screw, or the like. The elastic cord 71 is preferably a conventional cotton or nylon cord which comprises a stretchable core, yet other devices may be utilized without limiting the functions of the apparatus 10 .
It is envisioned that other styles and configurations of the present invention can be easily incorporated into the teachings of the present invention, and only one particular configuration shall be shown and described for purposes of clarity and disclosure and not by way of limitation of scope.
The preferred embodiment of the present invention can be utilized by the common user in a simple and effortless manner with little or no training. After initial purchase or acquisition of the apparatus 10 , it would be installed as indicated in FIG. 1 through 7 .
The method of installing and utilizing the apparatus 10 may be achieved by performing the following steps: acquiring the apparatus 10 ; lowering the gate 30 , thereby forcing the movable rod 25 downwardly thereto descend the cable 35 thereon the pulleys 33 and ascend the springs 36 ; locking the gate 30 , thereby pivoting the first counter weight 38 trapping the movable rod 25 between the first counter weight 38 and the diverter gate 40 ; inserting a trash receptacle 15 therein the frame 18 ; raising the gate 30 , thereby forcing the movable rod 25 downwardly to pivot the second counter weight 39 which simultaneously pivots the diverter gate 40 enabling the movable rod 25 to travel upwardly to its original position; utilizing the side entrance to fill the trash receptacle 15 with desired items, thereby removing the cord hook 73 from the corresponding post 32 and side pipe 27 and enabling the screening 21 to collapse and entering the apparatus 10 ; replacing the cord hooks 73 as desired; allowing a pair of loading arms thereon a garbage truck to lower the gate 30 in a manner as abovementioned for emptying of the trash receptacle 15 and replacing as desired; and, allowing the apparatus 10 to visually cover and physically protect trash receptacle 15 without the disadvantages of conventional gates in a manner which is quick and effective.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention and method of use to the precise forms disclosed. Obviously many modifications and variations are possible in light of the above teaching. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application, and to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions or substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.
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A dumpster screen comprising a fenced enclosure around one (1) or more trash dumpsters commonly found by commercial establishments. The fence material is made of an outdoor weather-proof textile material supported on its vertical sides using fence posts and along its horizontal edges using cables. A front portion of the enclosure, typically accessed by trucks to empty the dumpsters, comprises a gate portion. This enables the incoming truck to lower its forks across the reinforced top of said gate and continue lowering it until it can remove the dumpster in the normal manner. After emptying, the dumpster is replaced in the same manner and the front barrier automatically returns to position.
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FIELD OF THE INVENTION
[0001] The invention relates to chemical compounds having kinase inhibitory activity and their use in the treatment of diseases and conditions associated with inappropriate kinase activity.
BACKGROUND OF THE INVENTION
[0002] Protein kinases are key elements in signal transduction pathways responsible for transducing extracellular signals to the nuclei, triggering various biological events. [Schlessinger, J. and Ullrich, A., “Growth factor signaling by receptor tyrosine kinases,” Neuron, 9:383-391 (1992)] The many roles of protein tyrosine kinases (PTKs) in normal cell physiology include cell growth, differentiation, apoptosis, cell mobility and mitogenesis. [Plowman et al., “Receptor tyrosine kinases as targets for drug intervention,” DN & P, 7:334-339 (1994)].
[0003] Protein kinases include, for example, but are not limited to, extracellular signal-regulated kinases, p42/ERK 2 and p44/ERK1; c-Jun NH 2 -terminal kinase (JNK); cAMP-responsive element-binding protein kinases (CREB); cAMP-dependent kinase (CAPK); mitogen-activated protein kinase-activated protein kinase (MAPKAP); stress-activated protein kinase p38/SAPK2; mitogen-and stress-activated kinase (MSK); p185 neu /Her-2/erbB-2; platelet derived growth factor receptor kinase (PDGFR); colony stimulating factor-1 receptor kinase (CSF1-R); endothelial growth factor receptor kinase (EGF-R); vascular endothelial growth factor kinase (VEGF-R); fibroblast growth factor receptor kinase (FGF-R); protein kinases, PKA, PKC and PKC-α; serine/threonine protein kinase (STK); the Janus family of tyrosine protein kinases, JAK1, JAK2 and JAK 3; human insulin receptor tyrosine kinase; the Src-family of cytoplasmic PTKs, p60 c-arc , c-Src, Hck, Fgr and Lyn; Abelson leukemia virus PTK (c-Abl); p56 fyn (FYN); p56 lck (LCK); cyclin-dependent kinases (CDK1, CDK2, CDK3 and CDK4); NGF receptor kinase (Trk); Alk receptor kinase; IKK-β kinase; Ax1/Ufo kinase; Rse/Sky kinase; Syk kinase; ZAP-70 kinase; NIK kinase; Yrk kinase; Fyk kinase; Blk kinase; Csk kinase; Tie-1 and Tie-2 kinase; TrkA, TrkB and Trk C kinases; and human growth factor kinase (HGF).
[0004] The disruption of the norrnal functions of kinases has been implicated in many human diseases, including cancer, diabetes, restenosis, atherosclerosis, fibrosis of the liver and kidney and psoriasis. [Powis, G. and Workman, P., “Signaling targets for the development of cancer drugs,” Anti - Cancer Drug Design, 9:263-277 (1994); Cantley et al., “Oncogenes and signal transduction,” Cell, 64:281-302 (1991); Kolibaba, K. S. and Druker, B. J., “Protein tyrosine kinase and cancer,” Biochim Biophys Acta, 1333:F217-F248 (1997); Merenmies et al., “Receptor tyrosine kinase signaling in vascular development,” Cell Growth Differ, 8:3-10 (1997); Lavelle, F., “American Association for Cancer Research 1997: Progress and New Hope in the Fight Against Cancer,” Exp Opin Invest Drugs, 6:771-775 (1997); and Shawver et al., “Receptor tyrosine kinases as targets for inhibition of angiogenesis,” Drug Discovery Today, 2:50-63 (1997)] In fact, about 30% of human breast and ovarian cancer patients have exhibited increased expression of Her-2 (p185 neu ). [Plowman et al., “Receptor tyrosine kinases as targets for drug intervention,” DN & P, 7:334-339 (1994)] Platelet-derived growth factor receptor tyrosine kinases have been associated with human malignancies, arterial restenosis, and fibrosis of the liver, lung and kidney. Colony stimulating factor-1 receptor has been implicated in bone remodeling and hematopoiesis. Vascular endothelial growth factor (VEGF) is a homodimeric peptide growth factor which binds to two structurally related tyrosine kinase receptors denoted Flt1 and KDR. [Waltenberger et al. (Ludwig Institute for Cancer Research, Uppsala Branch, Sweden), “Different signal transduction properties of KDR and Flt1, two receptors for vascular endothelial growth factor,” J. Biol. Chem., 269:26988-95 (1994)]. VEGF receptor tyrosine kinases have been implicated in tumor angiogenesis, psoriasis, rheumatoid arthritis, atherosclerosis, and ocular diseases. [Shawver et al., “Receptor tyrosine kinases as targets for inhibition of angiogenesis,” Drug Discovery Today, 2:50-63 (1997)]
[0005] Further examples of the role of inappropriate kinase activities in various disease states and conditions include, but are not limited to, JAK2 kinase: myelo- and lymphoproliferative disorders [ Science, 278:1309-1312 (1997); Blood, 93:2369-2379 (1999)]; Fyn kinase: T-cell leukemia and lymphoma [ Curr. Opin. Immunol., 6:372-379 (1994)]; Fgr, Lyn and Hck kinases: rheumatoid arthritis and Crone's disease [ J. Exper. Med., 185:1661-1670 (1997)]; Lck kinase: T-cell leukemia and lymphoma [ Curr. Opin. Immunol., 6:372-379 (1994)]; Csk kinase: rheumatoid arthritis [ J. Clin. Invest., 104:137-146 (1999)]; PKA and PKC kinases: diabetic complications such as blindness [ Proc. N.Y. Acad. Sci., 89:11059 (1992)]; c-Abl kinase: chronic myelogenous leukemia [ Blood, 93:3973-3982 (1999); J. Cancer Res. Clin. Oncol, 124:643-660 (1998)]; FGFR kinase: Crouzon syndrome, achondroplasia, thanatophoric dysplasia, leukemia, lymphoma and other autoimmune disorders [ Nature Genetics, 8:98 (1994); Cell, 78:335 (1994); Nature Genetics, 13:233 (1996)]; ERK1 and ERK2 kinases: head and neck carcinoma [ Br. J. Cancer, 80:1412-1419 (1999)]; Tie-1 and Tie-2 kinases: breast cancer [ Cancer Research, 59:3185-3191 (1999); Br. J. Cancer, 77:51-56 (1998)]; TrkA, TrkB and TrkC kinases: neuroblastoma [ Clin. Cancer Res., 5:1491-1496 (1999)]; IKK-β kinase: inflammation and rheumatoid arthritis [ Cell, 90:373-383 (1997); Nature, 388:548-554 (1997); Published PCT application WO 99/34000]; MAPKAP kinase: inflammation and rheumatoid arthritis [ Nat. Cell Biol., 1:94-97 (1999)]; p38/SAPK2 kinase: inflammation and rheumatoid arthritis [ J. Bio. Chem., 274:19559-19564 (1999); Nature, 372:739-746 (1994); Ann. N.Y. Acad. Sci., 696:149-170 (1993)]; VEGFR kinase: melanoma, cancer, tumor angiogenesis, psoriasis, rheumatoid arthritis, atherosclerosis, ocular diseases and vascular disorders [ Blood, 94:984-993 (1999); McMahon et al., “Protein kinase inhibitors: structural determinants for target specificity,” Drug Discovery & Development, 1:131-146 (1998)]; HGF kinase: carcinoma and cancer [ Int. J. Cancer, 82:449-458 (1999); Jikken Igaku, 16:2016-2025 (1998)]; p185 neu /Her-2 kinase: breast cancer [ Nature, 385:540-544 (1997)]; NIK kinase: inflammation [ Nature ( London ), 398:252-256 (1999)]; Ax1/Ufo kinase: myeloid leukemia and prostate cancer [ Nature, 368:753-756 (1993); Cancer Detect. Prev., 23:325-332 (1999)]; Rse/Sky kinase: tumors and cell proliferation and breast cancer [ J. Biol. Chem., 270:6872-6880 (1995)]; c-Src kinase: colon and breast cancer [ Biochem. Biophys. Res. Commun., 250:27-31 (1998); Bone ( Osaka ), 10:135-144 (1996)]; NGF receptor kinase-Trk: colon cancer [ Proc. Nat. Acad. Sci., 91:83-87 (1994); Proc. Nat. Acad. Sci., 84:2251-2253 (1987)]; PDGF kinase: chronic myelomonocytic leukemia, arteriosclerosis and fibrosis of the liver, lung and kidney [ Oncogene, 7:237-242 (1992); New Engl. J. Med., 314:488-500 (1986)]; Alk receptor kinase: lymphoma [ Cell, 77:307-316 (1994); Blood, 93:3088-3095 (1999); Oncogene, 14:4035-4039 (1997)]; Syk kinase: anaplastic large cell lymphoma [ Science, 263:1281-1284 (1994); FEBS Lett., 427:139-143 (1998); J. Biol. Chem., 273:4035-4039 (1998)]; HRTK kinase: diabetes [ Science, 284:974-977 (1999); Diabetes, 38:1508 (1989)]; ZAP-70 kinase: immune disorders [ Curr. Biol., 9:203-206 (1999); EGFR kinase: carcinoma, psoriasis [ Cancer Research, 57:4838-4848 (1997); Cell, 61:203-212 (1990); J. Oncology, 4:277-296 (1994); U.S. Pat. No. 5,654,307 (Aug. 5, 1997)]; JAK3 kinase: immune suppression, leukemia and organ transplant rejection [ Adv. Immunology, 60:1-35 (1995); Leuk. Lymphoma, 32:289-297 (1999)]; Science, 270:797-800 (1995)]; and CDK2 kinase: bladder cancer (Published PCT application WO97/16452).
[0006] Inappropriate protein kinase activities thus represent attractive targets for therapeutic intervention and in fact, several small molecule kinase inhibitor compounds have been disclosed. Natural products such as staurosporine, lavendustin A, erbstatin, genistein and flavopiridol for example, have been shown to be effective kinase inhibitors. In addition, a number of synthetic tyrosine kinase inhibitors have also been introduced. [McMahon et al., “Protein kinase inhibitors: structural determinants for target specificity,” Drug Discovery & Development, 1:131-146 (1998)]. The present invention relates to novel compounds effective as inhibitors of inappropriate kinase activities.
SUMMARY OF THE INVENTION
[0007] The compounds of the present invention are effective as inhibitors of inappropriate kinase activities and therefore, are useful for the inhibition, prevention and suppression of various pathologies associated with such activities, such as, for example, inflammation, asthma, arthritis, diabetes, atherosclerosis, ocular diseases, restenosis, autoimmune responses, multiple sclerosis, psoriasis, human cancers, fibrosis of the liver, lung and kidney, transplantation rejection, and tumor metastasis.
[0008] Accordingly, in one embodiment, the present invention provides a compound, or a salt thereof, represented by Formula I:
wherein:
R 1 is chosen from —H, C 1 to C 20 hydrocarbon, aminocarbonylalkyl, alkoxyalkyl, substituted arylalkyl, heteroaryl, heteroarylalkyl, heterocyclylalkyl, and substituted heterocyclylalkyl; R 2 is chosen from halogen, C 1 to C 20 hydrocarbon, hydroxy, heteroaryl, substituted heteroaryl, heterocyclyl, substituted heterocyclyl,
wherein
R 5 is chosen from —H, alkyl and substituted alkyl; R 6 is chosen from a direct bond, alkyl, aryl, substituted aryl and heteroaryl; and R 7 is chosen from —H, acyl, alkyl, substituted alkyl, alkoxycarbonyl, amidine, aryl, arylalkyl, heterocyclyl, heteroaryl, substituted heteroaryl, substituted aryloxy, heteroarylsulfonamido, dialkylsulfonamido,
wherein
R 8 is chosen from —H and alkyl; and R 9 is chosen from —H, alkyl, substituted alkyl, aryl, heteroaryl, alkylcarbonyl and arylcarbonyl; R 3 is chosen from a direct bond,
wherein the left hand bond is the point of attachment to the ring and the right hand bond is the point of attachment to R 4 ;
R 4 is chosen from —H, halogen, alkyl, heterocyclyl, alkylamino, aminocarbonyl,
wherein
R 10 is chosen from —H, —OH, alkyl, cycloalkyl and substituted cycloalkyl; R 11 is chosen from —H, —OH, —COOH, aryl, substituted aryl, heteroaryl, substituted heteroaryl, aryl substituted alkyl, cycloalkyl, substituted cycloalkyl, alkoxy, aminocarbonyl, aminocarbonylalkyl,
R 12 is chosen from alkyl and aryl; R 13 is chosen from —H and aryl; R 14 is chosen from aryl, substituted aryl, heteroaryl, substituted alkyl, aryl substituted alkyl and alkoxy substituted alkyl, R 15 is chosen from alkyl, aryl, substituted aryl and substituted alkyl; R 16 is chosen from aryl, substituted aryl, heteroaryl, carboxyl, alkoxy, substituted alkyl, cycloalkyl, substituted cycloalkyl, aminocarbonyl, substituted aminocarbonyl, heterocyclyl and
R 17 is chosen from alkyl and dialkylamino; and R 18 is chosen from C 1 to C 20 hydrocarbon, substituted C 1 to C 20 hydrocarbon and heteroaryl; Y is chosen from —H and lower alkyl, or Y and R 1 taken together with the attached N, may be chosen from heterocyclyl, substituted heterocyclyl, heteroaryl and substituted heteroaryl; and wherein at least two of X, X 1 and X 2 are —N═, and the other is chosen from —C(H)═ and —N═.
[0029] Compounds of Formula I thus include those wherein each of X, X 1 and X 2 is —N═ and those wherein two of X, X 1 and X 2 are —N═ and the other is —C(H)═.
[0030] Preferred compounds of Formula I, wherein each of X, X 1 and X 2 is —N═ include:
[0031] A) Compounds wherein:
R 1 is chosen from C 1 to C 20 hydrocarbon and substituted arylalkyl; R 2 is
wherein
R 5 and R 7 are each —H and R 6 is chosen from substituted aryl and heteroaryl;
R 3 is chosen from
and preferably, from
R 4 is —C(O)NHR 15 wherein
R 15 is substituted aryl.
[0039] B) Compounds wherein:
R 1 is chosen from C 1 to C 20 hydrocarbon, aminocarbonylalkyl, heteroarylalkyl and substituted arylalkyl; R 2 is chosen from
wherein
R 5 is chosen from —H and substituted alkyl; and R 7 is chosen from —H, —C(O)NR 8 R 9 , —C(NH)NR 8 R 9 and —NR 8 R 9 wherein
R 8 is —H; and R 9 is chosen from —H, alkyl, aryl and arylcarbonyl;
R 3 is chosen from
and preferably, from
R 4 is —H.
[0048] C) Compounds wherein:
R 2 is
wherein
R 5 is chosen from —H and alkyl; and R 7 is chosen from heterocyclyl, substituted heteroaryl, —H, aryl, heteroaryl, substituted alkyl and —NR 8 R 9 wherein
R 8 is alkyl; and R 9 is substituted alkyl;
is chosen from
and preferably, from
and
R 4 is chosen from —C(S)NHR 12 , —C(O)NHR 15 and —C(O)(CH 2 ) 0-2 R 16 wherein
R 12 is aryl; R 15 is substituted aryl; and R 16 is chosen from substituted aryl and heteroaryl.
[0059] D) Compounds wherein:
R 1 is chosen from C 1 to C 20 hydrocarbon, aminocarbonylalkyl, substituted arylalkyl, heteroarylalkyl, heterocyclylalkyl, and substituted heterocyclylalkyl; R 2 is chosen from
wherein
R 5 is —H; and R 7 is chosen from —H, heteroaryl, substituted heteroaryl, and —NR 8 R 9 wherein
R 9 is chosen from alkyl carbonyl and substituted alkyl;
R 3 is chosen from
and preferably, from
and
R 4 is chosen from —H and —C(O)(CH 2 ) 0-2 R 16.
[0067] E) Compounds wherein:
R 1 is chosen from C 1 to C 20 hydrocarbon, alkoxyalkyl, substituted arylalkyl, heteroarylalkyl, and substituted heterocyclylalkyl; R 2 is chosen from
wherein
R 5 is chosen from —H and alkyl; and R 7 is chosen from —H, heterocyclyl, substituted alkyl, heteroarylsulfonamido, dialkylsulfonamido,
and —NR 8 R 9 wherein
R 9 is chosen from alkylcarbonyl, alkyl, substituted alkyl, aryl and arylcarbonyl;
R 3 is chosen from a direct bond,
and preferably, from
R 4 is chosen from —H,
—C(S)NHR 12 , —CHR 13 R 14 , —C(O)NHR 15 and —C(O)(CH 2 ) 0-2 R 16 wherein
R 10 is —H; R 11 is —H; R 12 is alkyl; R 13 is —H; R 14 is chosen from heteroaryl, substituted aryl and alkoxy substituted alkyl; R 15 is chosen from aryl and substituted aryl; and R 16 is substituted aryl.
[0082] F) Compounds wherein:
R 14 is chosen from aryl, substituted aryl, heteroaryl, substituted alkyl and aryl substituted alkyl.
[0084] G) Compounds wherein:
R 1 is heteroaryl; R 2 is chosen from halogen and
R 3 is chosen from a direct bond,
preferably, from
R 4 is chosen from —C(O)(CH 2 ) 0-2 R 16 and
[0089] The principles of the present invention also provide methods of inhibiting inappropriate kinase activity in a mammal, wherein the methods comprise administering to the mammal an effective amount of a compound represented by Formula I, or a prodrug or salt thereof. As used herein, inhibiting kinase activity is intended to include inhibiting, suppressing and preventing conditions associated with inappropriate kinase activity, including but not limited to, inflammation, asthma, arthritis, diabetes, atherosclerosis, ocular diseases, restenosis, autoimmune responses, multiple sclerosis, psoriasis, human cancers, fibrosis of the liver, lung and kidney, transplantation rejection, and tumor metastasis.
[0090] The principles of the present invention therefore also provide methods of treating a disease or condition associated with inappropriate kinase activity. The methods comprise administering to a mammal in need of such treatment, an effective amount of a compound represented by Formula I, or a prodrug or salt thereof, to inhibit kinase activity, such that the activity is regulated to treat, ameliorate or prevent the disease state or condition associated with that kinase activity. Such conditions include for example, but are not limited to, inflammatory and autoimmune responses, diabetes, asthma, arthritis, atherosclerosis, ocular diseases, restenosis, psoriasis, multiple sclerosis, human cancers, fibrosis of the liver, lung and kidney, inflammatory bowel disease, transplantation rejection, and tumor metastasis. As used herein, “treatment” of a mammal is intended to include prophylaxis and amelioration as well.
[0091] Accordingly, the compounds of the invention, as well as prodrugs or salts thereof, may be used in the manufacture of a pharmaceutical composition or medicament for the prophylactic or therapeutic treatment of disease states in mammals. The compounds of the present invention may be administered as pharmaceutical compositions as a monotherapy, or in combination with other therapeutic agents, such as, for example, other antiinflammatory and/or immunosuppressive agents. Such other agents may include, for example, antirheumatic, steroid, corticosteroid, NSAID, antipsoriatic, bronchodilator, antiasthmatic and antidiabetic agents. Combination therapies can involve the administration of the pharmaceuticals as a single dosage form or as multiple dosage forms administered at the same time or at different times.
[0092] Any suitable route of administration may be employed for providing a patient with an effective amount of a compound of the present invention. Suitable routes of administration may include, for example, oral, rectal, nasal, buccal, parenteral (such as, intravenous, intrathecal, subcutaneous, intramuscular, intrasternal, intrahepatic, intralesional, intracranial, intra-articular, and intra-synovial), transdermal (such as, for example, patches), and the like. Due to their ease of administration, oral dosage forms, such as, for example, tablets, troches, dispersions, suspensions, solutions, capsules, soft gelatin capsules, and the like, may be preferred. Administration may also be by controlled or sustained release means and delivery devices. Methods for the preparation of such dosage forms are well known in the art.
[0093] Pharmaceutical compositions incorporating compounds of the present invention may include pharmaceutically acceptable carriers or excipients, in addition to other therapeutic ingredients. Excipients such as starches, sugars, microcrystalline cellulose, diluents, lubricants, binders, coloring agents, flavoring agents, granulating agents, disintegrating agents, and the like may be appropriate depending upon the route of administration. Because of their ease of administration, tablets and capsules represent the most advantageous oral dosage unit forms. If desired, tablets may be coated by standard aqueous or nonaqueous techniques.
[0094] The compounds of the present invention may be used in the form of pharmaceutically acceptable salts derived from inorganic or organic bases, and hydrates thereof. Included among such base salts are ammonium salts, alkali metal salts, such as sodium and potassium salts, alkaline earth metal salts, such as calcium and magnesium salts, salts with organic bases, such as dicyclohexylamine salts, N-methyl-D-glucamine, and salts with amino acids such as arginine, lysine, and so forth.
DETAILED DESCRIPTION OF THE INVENTION
Abbreviations & Definitions
[0095] The following terms and abbreviations retain the indicated meaning throughout this disclosure.
ATP=adenosine triphosphate DCE=dichloroethylene DCM=dichloromethane=methylene chloride=CH 2 Cl 2 DIC=diisopropylcarbodiimide DIEA=N,N-diisopropylethylamine DMF=N,N-dimethylformamide DMSO=dimethyl sulfoxide DTT=dithiothreitol EDTA=ethylenediaminetetraacetic acid Fmoc=9-fluorenylmethoxycarbonyl GST=glutathione S-transferase HOBt=1-hydroxybenzotriazole MES=2-(N-morpholino)ethanesulfonic acid i-Pr 2 NEt=diisopropylethylamine Pr 2 NEt=dipropylethylamine TBS=t-butyldimethylsilyl TFA=trifluoroacetic acid THF=tetrahydrofuran
[0114] “Alkyl” is intended to include linear or branched hydrocarbon structures and combinations thereof of 1 to 20 carbons. “Lower alkyl” means alkyl groups of from 1 to about 10, preferably from 1 to about 8, and more preferably, from 1 to about 6 carbon atoms. Examples of such radicals include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, octyl and the like.
[0115] “Aryl” means an aromatic hydrocarbon radical of 4 to about 16 carbon atoms, preferably of 6 to about 12 carbon atoms, and more preferably of 6 to about 10 carbon atoms. The rings may optionally be substituted with 1-3 substituents selected from alkyl, halogen, hydroxy, alkoxy, aryloxy, haloalkyl, phenyl and heteroaryl. Examples of aryl groups are phenyl, biphenyl, 3,4-dichlorophenyl and naphthyl.
[0116] “Arylalkyl” denotes a structure comprising an alkyl attached to an aryl ring. Examples include benzyl, phenethyl, 4-chlorobenzyl, and the like.
[0117] “Cycloalkyl” refers to saturated hydrocarbon ring structures of from 3 to 12 carbon atoms, and preferably from 3 to 6 carbon atoms. Examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 2-methylcyclopropyl, cyclopropylmethyl, cyclopentylmethyl, norbomyl, adamantyl, pinanyl, myrtanyl and the like. “Lower cycloalkyl” refers to cycloalkyl of 3 to 6 carbons.
[0118] C 1 to C 20 hydrocarbon radicals include alkyl, cycloalkyl, alkenyl, alkynyl, aryl and combinations thereof. Examples include phenethyl, cyclohexylmethyl and naphthylethyl.
[0119] “Heterocyclyl” refers to a cyclic hydrocarbon structure of from 1 to 6, preferably 5 to 6, carbon atoms, and containing from 1 to 4 heteroatoms chosen from O, N and S; or a bicyclic 9- to 10-membered heterocyclic system containing from 1 to 4 heteroatoms chosen from O, N and S. “Heteroaryl” refers to an unsaturated cyclic hydrocarbon structure of from 1 to 6, preferably 5 to 6, carbon atoms, and containing from 1 to 4 heteroatoms chosen from O, N and S; or a bicyclic 9- or 10-membered heteroaromatic ring system containing 1-4 heteroatoms selected from O, N and S. The methine H atoms of a heterocyclyl or heteroaryl structure may be optionally substituted with alkyl, alkoxy or halogen. Examples include: imidazole, pyridine, indole, thiophene, benzopyranone, thiazole, furan, benzimidazole, quinoline, isoquinoline, quinoxaline, pyrimidine, pyrazine, tetrazole, pyrazole, pyrrolyl, pyridinyl, pyrazolyl, triazolyl, pyrimidinyl, pyridazinyl, oxazolyl, thiazolyl, imidazolyl, indolyl, thiophenyl, furanyl, tetrazolyl, 2-pyrrolinyl, 3-pyrrolinyl, pyrrolindinyl, 1,3-dioxolanyl, imidazolinyl, imidazolidinyl, pyrazolinyl, pyrazolidinyl, isoxazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,3-triazolyl, 1,3,4-thiadiazolyl, 2H-pyranyl, 4H-pyranyl, piperidinyl, 1,4-dithianyl, thiomorpholinyl, pyrazinyl, piperazinyl, 1,3,5-triazinyl, 1,2,5-trithianyl, benzo(b)thiophenyl, benzimidazolyl, quinolinyl, and the like.
[0120] “Alkoxy” means a straight, branched or cyclic hydrocarbon configuration and combinations thereof, including from 1 to 20 carbon atoms, preferably from 1 to 8 carbon atoms, more preferably from 1 to about 4 carbon atoms, and an oxygen atom at the point of attachment. Suitable alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, sec-butoxy, tert-butoxy, cyclopropyloxy, cyclohexyloxy, and the like. “Lower alkoxy” refers to alkoxy groups having from 1 to 4 carbon atoms.
[0121] “Alkenyl” refers to an unsaturated acyclic hydrocarbon radical in so much as it contains at least one double bond. “Lower alkenyl” refers to such radicals containing from about 2 to about 10 carbon atoms, preferably from about 2 to about 8 carbon atoms and more preferably 2 to about 6 carbon atoms. Examples of suitable alkenyl radicals include propenyl, buten-1-yl, isobutenyl, penten-1-yl, 2-methylbuten-1-yl, 3-methylbuten-1-yl, hexen-1-yl, hepten-1-yl, and octen-1-yl, and the like.
[0122] “Alkynyl” refers to an unsaturated acyclic hydrocarbon radical containing at least one triple bond. Examples include ethynyl, propynyl, and the like.
[0123] “Substituted alkyl” means an alkyl wherein at least one hydrogen attached to an aliphatic carbon is replaced with a substituent such as alkyl, amino, alkoxy, aryl, cyano, carboxyl, alkoxycarbonyl, halogen, alkylamino, alkyloxy, alkylcyano, acetyl, hydroxyl, alkylthio, alkylsulphonyl, carboxyalkyl, alkoxyalkyl, alkoxycarbonylalkyl, haloalkyl, acylamino, dialkylamino, and nitro. Examples of such substituent groups include cyano, methyl, isopropyl, methoxy, ethoxy, propoxy, amino, methylamino, phenyl, naphthyl, chlorine, fluorine, and the like.
[0124] “Substituted cycloalkyl” means a cycloalkyl wherein at least one hydrogen attached to a ring carbon is replaced with a substituent such as alkyl, amino, alkoxy, aryl, cyano, carboxyl, alkoxycarbonyl, halogen, alkylamino, alkyloxy, alkylcyano, acetyl, hydroxyl, alkylthio, alkylsulphonyl, carboxyalkyl, alkoxyalkyl, alkoxycarbonylalkyl, haloalkyl, acylamino, dialkylamino, and nitro. Examples of such substituent groups include cyano, methyl, isopropyl, methoxy, ethoxy, propoxy, amino, methylamino, phenyl, naphthyl, chlorine, fluorine, and the like.
[0125] “Substituted aryl” means an aryl wherein at least one methine hydrogen attached to an aromatic carbon is replaced with a substituent such as alkyl, amino, alkoxy, aryl, acetamido, acetyl, cyano, carboxyl, alkoxycarbonyl, halogen, alkylamino, alkyloxy, alkylcyano, alkylthio, alkylsulphonyl, aminosulphonyl, carboxyalkyl, alkoxyalkyl, alkoxycarbonylalkyl, haloalkyl, acylamino, aminocarbonyl, dialkylamino, and nitro. Examples of such substituent groups include cyano, methyl, isopropyl, methoxy, ethoxy, propoxy, amino, methylamino, phenyl, naphthyl, chlorine, fluorine, and the like. Examples include aryl amides, aryl carboxylic acids, aryl carboxylic acid esters, aryl amidines, and the like, such as benzamide, benzoic acid, benzoic acid ester, benzamidine derivatives and the like.
[0126] “Substituted heteroaryl” or “substituted heterocyclyl” means a heteroaryl or heterocyclyl optionally substituted with such substituents as alkyl, amino, alkoxy, aryl, acetyl, cyano, oxo, carboxyl, alkoxycarbonyl, halogen, alkylamino, alkyloxy, alkylcyano, alkylthio, alkylsulphonyl, carboxyalkyl, alkoxyalkyl, alkoxycarbonylalkyl, haloalkyl, acylamino, dialkylamino, and nitro. Examples of such substituent groups include cyano, methyl, isopropyl, methoxy, ethoxy, propoxy, amino, methylamino, phenyl, naphthyl, chlorine, fluorine, and the like.
[0127] “Substituted arylalkyl” means an arylalkyl optionally substituted with such substituents as alkyl, amino, alkoxy, aryl, acetyl, cyano, carboxyl, alkoxycarbonyl, halogen, alkylamino, alkyloxy, alkylcyano, alkylthio, alkylsulphonyl, aminosulphonyl, carboxyalkyl, alkoxyalkyl, alkoxycarbonylalkyl, haloalkyl, acylamino, dialkylamino, and nitro. Examples of such substituent groups include cyano, methyl, amino, isopropyl, methoxy, ethoxy, propoxy, methylamino, phenyl, naphthyl, chlorine, fluorine, and the like.
[0128] “Halogen” is intended to include for example, F, Cl, Br and I.
[0129] The term “prodrug” refers to a chemical compound that is converted to an active agent by metabolic processes in vivo. [See, e.g., N. Boder and J. J. Kaminski, Ann. Rep. Med. Chem. 22:303 (1987) and H. Bundgarrd, Adv. Drug Delivery Rev., 3:39 (1989)]. With regard to the present invention, a prodrug of a compound of Formula I is intended to mean any compound that is converted to a compound of Formula I by metabolic processes in vivo. The use of prodrugs of compounds of Formula I in any of the methods described herein is contemplated and is intended to be within the scope of the invention.
[0130] Terminology related to “protected,” “protecting” and/or “deprotecting” functionalities is used throughout this application. Such terminology is well understood by persons of skill in the art and is used in the context of processes which involve sequential treatment with a series of reagents. In this context, a protecting group refers to a group which is used to mask a functionality during a process step in which it would otherwise react, but in which reaction is undesirable. The protecting group prevents reaction at that step, but may be subsequently removed to expose the original functionality. The removal or “deprotection” occurs after the completion of the reaction or reactions in which the functionality would interfere. Thus, when a sequence of reagents is specified, as it is in the processes of the invention, the person of ordinary skill can readily envision those groups that would be suitable as “protecting groups” for the functionalities involved.
[0131] In the case of the present invention, the typical functionalities that must be protected are amines. Suitable groups for that purpose are discussed in standard textbooks in the field of chemistry, such as Protective Groups in Organic Synthesis by T. W. Greene [John Wiley & Sons, New York, 1991], which is incorporated herein by reference. Particular attention is drawn to the chapter entitled “Protection for the Amino Group” (pages 309-405). Preferred protecting groups include BOC and Fmoc. Exemplary methods for protecting and deprotecting with these groups are found in Greene and Wuts on pages 318 and 327.
[0132] The materials upon which the syntheses described herein are performed are referred to as solid supports, beads, and resins. These terms are intended to include: (a) beads, pellets, disks, fibers, gels, or particles such as cellulose beads, pore-glass beads, silica gels, polystyrene beads optionally cross-linked with divinylbenzene and optionally grafted with polyethylene glycol, poly-acrylamide beads, latex beads, dimethylacrylamide beads optionally cross-linked with N,N′-bis-acryloyl ethylene diamine, glass particles coated with hydrophobic polymer, etc., i.e., material having a rigid or semi-rigid surface; and (b) soluble supports such as polyethylene glycol or low molecular weight, non-cross-linked polystyrene. The solid supports may, and usually do, have functional groups such as amino, hydroxy, carboxyl, or halo groups; where amino groups are the most common.
[0133] Tentagel™ NH 2 (Rapp Polymere, Tubingen, Germany) is a preferred amine functionalized polyethylene glycol-grafted polystyrene resin. Tentagel™-S-PHB resin has a para-hydroxy benzyl linker which can be cleaved by the use of 90% trifluoroacetic acid in dichloromethane. Techniques for functionalizing the surface of solid phases are well known in the art. Attachment of lysine to the amino groups on a bead (to increase the number of available sites) and subsequent attachment of linkers as well as further steps in a typical combinatorial synthesis are described, for example, in PCT application WO95/30642, the disclosure of which is incorporated herein by reference. In the synthesis described in WO95/30642, the linker is a photolytically cleavable linker, but the general principles of the use of a linker are well illustrated.
Optical Isomers—Diastereomers—Geometric Isomers
[0134] Some of the compounds described herein contain one or more asymmetric centers and may thus give rise to enantiomers, diastereomers, and other stereoisometric forms which may be defined in terms of absolute stereochemistry as (R)- or (S)-, or as (D)- or (L)- for amino acids. The present invention is meant to include all such possible diastereomers as well as their racemic and optically pure forms. Optically active (R)- and (S)-, or (D)- and (L)-isomers may be prepared using chiral synthons or chiral reagents, or optically resolved using conventional techniques. When the compounds described herein contain olefinic double bonds or other centers of geometric asymmetry, and unless specified otherwise, it is intended to include both (E)- and (Z)-geometric isomers. Likewise, all tautomeric forms are intended to be included.
[0135] The configuration of any carbon-carbon double bond appearing herein is selected for convenience only and is not intended to designate a particular configuration; thus a carbon-carbon double bond depicted arbitrarily herein as trans may be cis, trans, or a mixture of the two in any proportion.
[0136] In view of the above definitions, other chemical terms used throughout this application can be easily understood by those of skill in the art. Terms may be used alone or in any combination thereof. The preferred and more preferred chain lengths of the radicals apply to all such combinations.
Utility
[0137] The compounds of the present invention have demonstrated utility as inhibitors of inappropriate kinase activity. The compounds shown in Table 1 have been synthesized according to the methods described herein and have been tested in accordance with the protocols described below. All of the compounds shown exhibited kinase inhibition with an IC 50 below 10 μM. Preferred compounds are those with an IC 50 below 5 μM. More preferred compounds are those with an IC 50 below 1 μM and most preferred are those with an IC 50 below 500 nM. These compounds are provided by way of illustration only, and the invention is not intended to be limited thereto.
Biological Assays
Compound Preparation and Assay Format
[0138] Compounds were dissolved in dimethylsulfoxide as 10 mM stock solutions. For IC 50 determinations, serial dilutions were made at 20× the final concentration used in the assay. Assays were carried out in 96-well U-bottom polypropylene microtiter plates.
Jak2 Assay—Casein Substrate/Filtermat Harvest
[0139] The final assay volume was 60 μl, prepared by first adding 3 μl of the test compound to 27 μl of a solution containing 5 μM ATP, 10 nM [γ- 33 P]ATP and 12 μM casein in assay buffer (20 mM Tris HCl, pH 8.0, 5 mM MgCl 2 , 1 mM EDTA and 1 mM DTT), followed by 30 μl of 20 nM GST-Jak2 in assay buffer. The plate was mixed by shaking and then incubated at ambient temperature for 45 min. and terminated by adding 5 μl of 0.5 M EDTA to each sample. The [γ- 33 P]-incorporated casein is harvested onto a GF/C filtermat (see below) Final concentrations of assay components are: [ATP], 2.5 μM; [casein], 6 μM (10 μg/well); [Jak], 10 nM (˜34 ng/well). Staurosporine (1 μM) was used to determine background counts. This assay would also be appropriate for Jak-3 inhibitory activity.
p38(SAPK2) or Erk1 Assay—Myelin Basic Protein/Filtermat Harvest
[0140] The assays are performed in V-bottomed 96-well plates. For both assays, the final assay volume is 60 μl prepared from three 20 μl additions of enzyme, substrates [myelin basic protein (MBP) and ATP] and test compounds in assay buffer (50 mM Tris pH 7.5, 10 mM MgCl 2 , 50 mM NaCl and 1 mM DTT). Bacterially expressed, activated p38 or Erk1 is pre-incubated with test compounds for 10 min. prior to initiation of reaction with substrates. The reaction is incubated at 25° C. for 45 min. and terminated by adding 5 μl of 0.5 M EDTA to each sample. The [γ- 33 P]-incorporated MBP is harvested onto a GF/C filtermat (see below). The final concentration of reagents in the assays are ATP, 1 μM; [γ- 33 P]ATP, 3 nM; MBP (bovine brain, Sigma catalog #M1891), 2 μg/well; activated p38, 10 nM; activated Erk1 (Upstate Biotechnology catalog #14-188), 2.5 μg/mL, 10 nM; DMSO, 0.3%.
IKK-β Assay—GST-IkappaBalpha(1-54)/Filtermat Harvest
[0141] The final assay volume is 60 μl prepared from three 20 μl additions of 3× GST-IkappaBalpha(1-54) in assay buffer (20 mM HEPES pH 7.6, 5 mM MgCl 2 , 50 mM NaCl, 1 mM EDTA and 1 mM DTT) plus test compound, followed by the addition of 3× baculovirus expressed IKK-β (S177E; S181E) in assay buffer which is incubated for 10 min prior to initiation of reaction with a 3× ATP solution (6 μM ATP and 9 nM [γ- 33 P] ATP). The reaction is incubated at 37° C. for 30 min and terminated by harvesting onto a GF/C filtermat (see below). The final concentration of reagents in the assay are ATP, 2 μM; [γ- 33 P]ATP, 3 nM; GST-IkappaBalpha (1-54), 2 μg/well; IKK-β], 5 nM; DMSO, 0.3%.
CDK4 Assay—GST-RbSE Substrate/Filter Harvest
[0142] The final assay volume is 50 μl prepared from two 25 μl additions of 2× GST-RbSE(768-928) in assay buffer (50 mM HEPES pH 7.5, 10 mM MgCl 2 , 2.5 mM EDTA, 10 mM β-mercaptoethanol, 2 mM DTT), 20 μM ATP, 0.125 μCi [γ- 33 P]ATP plus test compound, followed by the addition of 2× baculovirus expressed His 6 -Cdk4/Cyclin D1 complex in assay buffer. The reaction is incubated at ambient temperature for 45 min. and terminated by addition of 50 μl of 250 mM EDTA followed by harvesting onto a GF/C filtermat (see below). The final concentration of reagents in the assay are ATP, 10 μM; [γ- 33 P]ATP, 10 nM (0.125 uCi); GST-RbSE(768-928), 2.5 μM; His 6 -Cdk4/Cyclin D1 complex (10 μg per well); DMSO max , 2%.
CDK3 Assay—Histone H1 Substrate/Filter Harvest
[0143] The final assay volume is 50 μl prepared from two 25 μl additions of 2× Histone H1 in assay buffer (50 mM HEPES pH 7.5, 10 mM MgCl 2 , 2.5 mM EDTA, 10 mM β-mercaptoethanol, 2 mM DTT), 20 μM ATP, 0.125 μCi [γ- 33 P]ATP plus test compound, followed by the addition of 2× baculovirus expressed Cdk2/His 6 -Cyclin E complex in assay buffer. The reaction is incubated at ambient temperature for 45 min. and terminated by addition of 50 μl of 250 mM EDTA followed by harvesting onto a GF/C filtermat (see below). The final concentration of reagents in the assay are ATP, 10 μM; [γ- 33 P]ATP, 10 nM (0.125 μCi); Histone H1, 0.5 μM (1.0 μg/well); Cdk2/His 6 -Cyclin E complex, 10 nM; DMSO max , 2%.
Protein Kinase A Assay—Histone H1 Substrate/Filter Harvest
[0144] The final assay volume is 50 μl prepared from two 25 μl additions of 2× Histone (type III-SS) in assay buffer (40 mM Tris-HCl, pH 7.8, Mg(OAc) 2 ), 20 μM ATP, 0.02 μCi [γ- 32 P]ATP plus test compound, followed by the addition of 2× baculovirus expressed Cdk2/ His 6 -Cyclin E complex in assay buffer. The reaction is incubated at ambient temperature for 45 min. and terminated quenching with 50 μl of 200 mM EDTA, 75 mM phosphoric acid followed by harvesting onto a GF/C filtermat (see below). The final concentration of reagents in the assay are ATP, 50 μM; [[γ- 32 P]ATP, x nM (0.02 μCi), Histone, 2.4 μg/well; PKA, 10U (0.21 μg); DMSO max , 2%.
Src Assay—Zeta Chain Substrate/Plate Binding
[0145] The Src kinase assay is based on the phosphorylation of a recombinant His 6 -zeta chain substrate peptide adsorbed to a Costar 96-well microtiter plate (EIA-RIA High Binding). (Alternatively, the His 6 -zeta chain can be adsorbed to a Xenopore Nickel plate. If background is a problem, TBS supplemented with 0.02% Tween 20 can replace TBS.)
[0146] This assay is carried out in a 50 μl volume. Plates are first coated with 8-12 μg/well zeta chain in 100 μl per well TBS and allowed to stand at 4° C. overnight, followed by a 3× wash with TBS. The plates are blocked using TBS, 1% BSA, 200 μl per well at ambient temperature for 1 hr, followed by a 3× TBS wash. 25 μl of Src (100 ng/well) in assay buffer (50 mM HEPES, pH 7.5 and 10 mM MgCl 2 ), followed by addition 25 μl of test compound and 20 μM ATP in assay buffer. The reaction is allowed to proceed for 45 min. at ambient temperature with shaking. The reaction is terminated by washing the plate 3× with TBS. Incorporated phosphate is determined by adding 5 ng/well anti-phosphotyrosine-Eu in 100 μl of TBS, 1% BSA, 50 μM DPTA and incubating at ambient temperature with shaking for 1 hr. The plate is washed 6× with TBS followed by the addition of 150 μl of enhancement buffer, shaken for 5 min. and measured on a Victor time-resolved plate reader. The final concentration of reagents in the plate are Src, 0.1U (100 ng); ATP, 10 μM; DMSO, 0.5%.
c-Abl Assay-Biotin Peptide Substrate/NeutrAvidin Plate Capture
[0147] The c-Abl kinase assay is based on the phosphorylation of a biotinylated substrate peptide bound to a NeutrAvidin (Pierce, Rockville, Ill.) coated flat bottom polystyrene 96-well microtiter plate. The phosphorylated peptide product is subsequently detected using an europium-labeled anti-phosphotyrosine antibody (Wallac Oy, Turku, Finland). Assay plates are made 24 hours in advance of the assay by coating a Costar EIA/RIA plate with 50 μl of 2 μg/mL NeutrAvadin in TBS using the a Tomtec liquid dispenser. The plate is allowed to stand for 2 hours at ambient temperature or overnight at 4° C. The plate is washed 3× with TBS, 0.1% Tween-20 (TBST). Using the Tomtec liquid dispenser, the plate is next coated with 40 μl of 100 nM Abl biotinylated substrate peptide (Glu-Ala-Ile-Tyr-Ala-Ala-Pro-Phe-Ala-Lys(ε-biotin)-NH 2 ) in TBS, 1.0% BSA. The plate is allowed to stand for 2 hours at ambient temperature or up to 1 week at 4° C., and then washed 3× with TBST.
[0148] The assay is carried out by the addition of 20 μl of test compound in assay buffer to the assay plate followed by addition of 40 μl of a mixture of c-Abl, ATP and anti-pY-Eu in assay buffer. The final concentrations of reagents per well in solution are c-abl, 3U; ATP, 2 μM; anti-pY-Eu, 0.1 μg/mL. The plate is vortexed lightly for 5 min. and the reaction is allowed to proceed for 1 hr. at ambient temperature. The reaction is quenched by washing 3× with TBST. Europium counts are measured following the addition of 100 μl Enhancement solution (Wallac) per well on a Victor time-resolved plate reader (Wallac).
VEGF Kinase Assay
[0149] This assay may be used to detect VEGF binding. VEGF is a peptide growth factor that binds to two structurally related tyrosine kinase receptors, Flt1 and KDR. Cultured human umbilical vein endothelial (HUVE) cells express two distinct populations of binding sites with affinities similar to those for Flt1 and KDR, respectively. The KDR expressing cells show striking changes in cell morphology, actin reorganization and membrane ruffling, chemotaxis and mitogenicity upon VEGF stimulation, whereas Flt1 expressing cells lack such responses. KDR undergoes ligand-induced autophosphorylation in intact cells, and both Flt1 and KDR are phosphorylated in vitro in response to VEGF, however, KDR much more efficiently than Flt1. [Waltenberger J. et al. (Ludwig Institute for Cancer Research, Uppsala Branch, Sweden), “Different signal transduction properties of KDR and Flt1, two receptors for vascular endothelial growth factor,” J. Biol. Chem., 269:26988-95 (1994)]
Zap-70 Kinase Assay
[0150] The assay is performed in black 384-well plates at a final volume of 20 μl. The bacterial expressed cytoplasmic domain of human erythrocyte band 3 (cdb3) is used as a protein substrate for Zap-70 kinase. The assay plates are coated with cdb3 (10 μg/mL) at 4° C. overnight, and washed with TBS once. 10 μl of test compounds in kinase buffer (25 mM MES, pH6.7, 10 mM MnCl 2 , 0.1% BSA and 2 μM ATP) is added to each well, followed by the addition of 10 μl diluted activated Zap-70 to initiate the reaction. The final concentration of reagents in the assays are ATP, 1 μM; MES pH 6.7 , 25 mM; MnCl 2 , 10 mM; BSA, 0.1%; DMSO, 1%. After incubation at 25° C. for 45 min., reaction solution is removed, and the plates are washed 3× with TBS. 20 μl of europium-labeled anti-phosphotyrosine antibody (Wallac catalog # CR03-100) at 0.25 μg/mL is added to each well. The plates are incubated at 25° C. for 1 hr with continuous shaking. The plates are washed 5 times with TBS before 25 μl of enhancement solution is added to each well. The time-resolved fluorescence is measured using a Victor reader (Wallac).
Reaction Termination by Filtration Harvesting and Data Analysis
[0151] After the designated time, the reaction mixture was aspirated onto a pre-wet filtermat using a Skatron Micro96 Cell Harvester (Skatron, Inc.), then washed with PBS. The filtermat is then dried in a microwave oven for 1 min., treated with MeltilLex A scintillation wax (Wallac Oy, Turku, Finland), and counted on a Microbeta scintillation counter Model 1450 (Wallac). Inhibition data were analyzed by nonlinear least-squares regression using Prizm (GraphPad Software).
Methods of Synthesis
[0152] General methods of synthesis for compounds of the present invention are illustrated by the following examples. The specific embodiments are presented by way of illustration only, and the invention is not to be limited thereto. Modifications and variations in any given material or process step will be readily apparent to one of skill in the art and are intended to be included within the scope of the invention.
Solution Phase Synthesis of Phenyl Amino Triazines
[0153] To a solution of cyanuric chloride (1.84 g; 10 mmol) in acetone (15 mL) at 0° C. was added 2-chloroaniline (1.28 g; 10 mmol) and 3.3 mL of 3 M NaOH (aq) (10 mmol). The mixture was stirred at 0° C. for 2 hr. The resultant thick slurry was poured into ice-cold water (approx. 40 mL) and filtered to collect the product as an off white solid. The solid product was then washed with cold H 2 O (2×) and cold ethanol (2×) and dried to afford 2.06 g of crude triazine 1 (75% yield) which was suitable for use without further purification. Data for 1: 1 H NMR (d 6 -DMSO, 300 MHz) 11.00 (s, 1H), 7.70-7.20 (m, 4H).
[0154] To a solution of cyanuric chloride (1.84 g; 10 mmol) in acetone (15 mL) at 0° C. was added 3-aminobenzamide (1.36 g; 10 mmol) and 3.3 mL of 3 M NaOH (aq) (10 mmol). The mixture was stirred at 0° C. for 2 hr. The resultant thick slurry was poured into ice-cold water (approx. 40 mL) and filtered to collect the product as an off-white solid. The solid product was then washed with cold H 2 O (2×) and cold ethanol (2×) and dried to afford 2.75 g of crude triazine 2 (80% yield) which was suitable for use without further purification. Data for 2: 1 H NMR (d 6 -DMSO, 300 MHz) 11.21 (s, 1H), 8.02 (s, 1H), 7.78 (d, 1H), 7.69(d, 1H), 7.45 (t, 1H).
[0155] Derivatization of Resin with bis-Fmoc-Lysine
[0156] The resin loading was effectively doubled by initial derivatization with bis-Fmoc-lysine using the following procedure. To a suspension of 10.12 g of ArgoGel (0.42 mmol/g, 4.25 mmol, 1.00 eq) in CH 2 Cl 2 (100 mL) in a large shaking vessel (200 mL capacity) was added bis-Fmoc-lysine (10.04 g, 17.00 mmol, 4 eq), DIC (2.66 mL, 17.00 mmol, 4 eq), and HOBt (2.30 g, 17.00 mmol, 4 eq). The resulting resin suspension was then shaken for 2 hr at 25° C. The resin was washed with DMF (5×) and CH 2 Cl 2 (5×) and dried in vacuo. The resulting bis-Fmoc-lysine derivatized resin 3 gave a negative result with both the ninhydrin and bromophenol blue tests (tests for primary amine and basic amine functionality).
[0157] Fmoc Deprotection of bis-Fmoc-Lysine Derivatized Resin
[0158] To 12.55 g (0.68 mmol/g, 8.53 mmol, 1.00 ed) of bis-Fmoc-lysine derivatized resin 3 in a large shaking vessel was added 100 mL of a 30% v/v solution of piperidine in DMF. The resulting suspension was shaken for 1 hr at 25° C. The resin was washed with DMF (5×) and CH 2 Cl 2 (5×). The resin-bound deprotected lysine gave a positive result with both the ninhydrin and bromophenol blue tests.
[0159] Acylation with the Acid Cleavable Linker
[0160] To 11.08 g (0.77 mmol/g, 8.53 mmol, 1.00 eq) of the resin-bound deprotected lysine in CH 2 Cl 2 (100 mL) was added the acid cleavable linker (8.13 g, 34.12 mmol, 4 eq), DIC (5.34 mL, 34.12 mmol, 4 eq), and HOBt (4.61 g, 34.12 mmol, 4 eq). The resulting suspension was shaken overnight at 25° C. The resin was washed with DMF (5×) and CH 2 Cl 2 (5×) and dried in vacuo. The resulting resin-bound product 4 gave a negative test with both the ninhydrin and bromophenol blue tests.
[0000] Preparation of Triazine 8:
[0161] First Combinatorial Step—Reductive Amination with a Primary Amine
[0162] To 300 mg (0.59 mmol/g, 0.177 mmol, 1.00 eq) of the resin-bound o-methoxybenzaldehyde 4 in DCE (10 mL) was added (S)-(+)-cyclohexylethylamine (0.184 mL, 1.24 mmol, 7 eq) and NaHB(OAc) 3 (188 mg, 0.885 mmol, 5 eq). The resulting suspension was shaken for 14 hr at 25° C. The resin was washed with DMF (5×) and CH 2 Cl 2 (5×) and then dried in vacuo. The resulting resin-bound secondary amine 5 gave a positive result with the bromophenol blue test.
[0163] Second Combinatorial Step—Alkylation with Phenylaminotriazine 1
[0164] To 320 mg (0.55 mmol/g, 0.176 mmol, 1.00 eq) of resin-bound secondary amine 5 in triglyme (10 mL) was added the triazine 1 (122 mg, 0.44 mmol, 2.5 eq) and 0.154 mL of i-Pr 2 NEt. The resulting suspension was heated to 80° C. overnight. The suspension was then filtered and the resin washed with DMF (5×) and CH 2 Cl 2 (5×). This was used without drying.
[0165] Third Step—Addition of Secondary Amine (thiomorpholine)
[0166] To 362 mg (0.49 mmol/g, 0.177 mmol, 1.00 eq) of resin-bound chlorotriazine 6 in triglyme (4 mL) was added thiomorpholine (1 mL). The resulting suspension was heated to 80° C. overnight. The suspension was filtered and the resin washed with DMF (5×) and CH 2 Cl 2 (5×) and then dried in vacuo.
[0167] Acid Cleavage of Resin-Bound Trisubstituted Triazine 7
[0168] To 319 mg (0.47 mmol/g, 0.150 mmol) of resin-bound triazine 7 was added 10 mL of a 1:1 solution of TFA/CH 2 Cl 2 . The resulting mixture was stirred for 2 hr at 25° C. and then filtered. The filtrate was concentrated in vacuo and the residue was purified by flash column chromatography (SiO 2 , elution with 3:1 hexanes:EtOAc) giving 45 mg of pure trisubstituted triazine 8.
[0000] Data for 8: MS: m/z (relative intensity) 433.3 (M + , 100), 435.3 (M + +2, 32).
[0169] Preparation of Triazine 10: First Combinatorial Step—Reductive Amination with a Primary Amine
[0170] To 300 mg (0.59 mmol/g, 0.177 mmol, 1.00 eq) of the resin-bound o-methoxybenzaldehyde 4 in DCE (10 mL) was added (S)-(+)-cyclohexylethylamine (0.184 mL, 1.24 mmol, 7 eq) and NaHB(OAc) 3 (188 mg, 0.885 mmol, 5 eq). The resulting suspension was shaken overnite at 25° C. The resin was washed with DMF (5×) and CH 2 Cl 2 (5×) and then dried in vacuo. The resulting resin-bound secondary amine 5 gave a positive result with the bromophenol blue test.
[0171] Second Combinatorial Step—Alkylation with Phenylaminotriazine 2
[0172] To 320 mg (0.55 mmol/g, 0.176 mmol, 1.00 eq) of resin-bound secondary amine 5 in triglyme (10 mL) was added the triazine 2 (120 mg, 0.44 mmol, 2.5 eq) and 0.154 mL of i-Pr 2 NEt. The resulting suspension was heated to 80° C. in an oven overnight. The suspension was then filtered and the resin washed with DMF (5×) and CH 2 Cl 2 (5×). This was used without drying.
[0173] Third Step—Addition of Primary Amine (1-(3-aminopropyl)imidazole)
[0174] To 364 mg (0.49 mmol/g, 0.178 mmol, 1.00 eq) of resin-bound chlorotriazine 9 in triglyme (4 mL) was added 1-(3-aminopropyl)imidazole (1 mL). The suspension was heated to 80° C. in an oven overnight. The suspension was filtered and the resin washed with DMF (5×) and CH 2 Cl 2 (5×). This was then dried in vacuo.
[0175] Acid Cleavage of Resin-Bound Trisubstituted Triazine 10
[0176] To 131 mg (0.47 mmol/g, 0.062 mmol) of resin-bound triazine 10 was added 10 mL of a 1:1 solution of TFA/CH 2 Cl 2 . The resulting mixture was stirred for 2 hr at 25° C. and then filtered. The filtrate was concentrated in vacuo and the residue was purified by flash column chromatography (SiO 2 , elution with 10% methanol in methylene chloride) giving 8 mg of pure trisubstituted triazine 11. Data for 11: MS: m/z (relative intensity) 464.3 (M + +1, 100).
[0177] To 1.0 g of magnesium turnings in 15 mL dry ethyl ether was added an iodine crystal and cyclohexylethyl bromide (0.95 g, 5.0 mmol). After 30 minutes the cloudy mixture was transferred to a solution of cyanuric chloride (0.92 g, 5.0 mmol) in 10 mL dry THF. After 2 hr the mixture was concentrated, taken up in DCM and washed with saturated NaHCO 3 and brine. The organic layer was dried over MgSO 4 . Filtration and removal of volatiles under reduced pressure gave 12 as an oil. (0.88 g, 3.4 mmol, 68%, M+H + =261)
[0178] To 12 (0.42 g, 1.6 mmol) in 20 mL acetone was added 6-aminobenzothiazole (0.29 g, 1.9 mmol) and stirred at room temperature for 1 hr. The mixture was concentrated, taken up in DCM and washed with saturated NaHCO 3 and brine. The organic layer was dried over MgSO 4 . Filtration and removal of volatiles under reduced pressure gave 13 as a solid. (0.022 g, 0.06 mmol, 4%, M+H + =374).
[0179] To 13 (0.022 g, 0.06 mmol) in 3 mL DCM was added 100 mg of piperazine and stirred at room temperature for 3 hr. The mixture was concentrated, dissolved in DCM and washed with saturated NaHCO 3 and brine. The organic layer was dried over MgSO 4 . Filtration and removal of volatiles under reduced pressure gave 14 as a solid. (0.013 g, 0.03 mmol, 50%, M+H + =424)
[0180] To (1R)-(−)-Myrentol in 10 mL THF was added methylamine (2.0M in THF, 7.5 mL), then NaHB(OAc) 3 and stirred at room temperature overnight. The mixture was then concentrated, dissolved in DCM and washed with saturated NaHCO 3 . The organic layer was extracted into 1N HCl and washed twice with DCM. The aqueous layer was adjusted to pH 12 with 3N NaOH and extracted with DCM. The combined organic layers were dried over MgSO 4 . Filtration followed by removal of volatiles under reduced pressure gave 15 as an oil (0.43 g, 2.6 mol, 26%, M+H + =166)
[0181] 0.26 g (1.6 mmol) of 15 was taken up in 15 mL EtOH and placed in a Parr hydrogenation apparatus with 50 mg of 10% Pd/C and shaken at 50 psi for 6 hr. The solution was filtered through Celite and concentrated. The resulting oil was taken up in DCM and washed with saturated NaHCO 3 and brine. The organic layer was dried over MgSO 4 . Filtration and removal of volatiles under reduced pressure gave 16 as an oil. (0.13 g, 0.75 mmol, 46%, M+H + =168)
[0182] Compound 16 (0.05 g, 0.3 mmol) was combined with 17 (0.09 g, 0.2 mmol) and DIEA (53 μL, 0.3 mmol) in 5 mL DMF and heated to 60° C. overnight. The mixture was then concentrated, taken up in DCM and washed with saturated KHSO 4 , saturated NaHCO 3 , and brine. The organic layer was concentrated to yield 18 as a foam. (0.055 g, 0.09 mmol, 32%, M+H + =579).
[0183] 16 mL (100 mmol) of (1R)-(−)-Myrentol was taken up in 50 mL ethanol. To this was added 25 mg of platinum oxide and placed on a Parr hydrogenator at 50 psi overnight. The mixture was then filtered through Celite and concentrated under reduced pressure to yield 19 as an oil. (15.0 g, 97 mmol, 97%, M+H + =155)
[0184] To NaH (0.52 g, 13 mmol) in 30 mL dry THF was added 19 (1.5 g, 10 mmol) in 10 mL dry THF slowly. After 10 minutes, cyanuric chloride (1.8 g, 10 mmol) in 10 mL dry THF was added slowly. The reaction mixture was stirred at room temperature overnight. Water (5 mL) was slowly added to the mixture. The mixture was then concentrated, dissolved in DCM and washed with saturated NaHCO 3 and brine. The organic layer was dried over MgSO 4 . Filtration and removal of volatiles under reduced pressure gave 20 as an oil. (0.64 g, 2.1 mmol, 21%, M+H + =303)
[0185] To NaH (0.07 g, 1.72 mmol) in 10 mL dry THF was added dropwise a solution of 6-aminobenzo thiazole (0.20 g, 1.33 mmol) in 5 mL dry THF. After 10 minutes, 20 (0.44 g, 1.46 mmol) in 5 mL dry THF was added dropwise. The reaction mixture was stirred at room temperature for 2 h, after which 5 mL of water was added slowly. The mixture was then concentrated, dissolved in DCM and washed with saturated NaHCO 3 and brine. The organic layer was dried over MgSO 4 . Filtration and removal of volatiles under reduced pressure gave 21 as a solid. (0.45 g, 1.1 mmol, 83%, M+H + =416)
[0186] Compounds of Formula I wherein two of X, X 1 and X 2 are —N═ and the other is —C(H)═ may be synthesized as follows:
[0187] Scheme 1 illustrates a solution phase synthesis via chloropyrimidines and Scheme 2 illustrates a solution phase synthesis via fluoropyrimidines. As shown in Scheme 1, 390 mg of the free amine 22 (1.1 mmol) is treated with 0.6 mL of i-Pr 2 NEt and 500 mg 6-imidazolyl-2,4-dichloropyrimidine (2.0 mmol) in DMF at 50° C. for 16 hr, then diluted with ethyl acetate and washed with saturated NH 4 Cl, H 2 O, brine, dried over MgSO 4 and concentrated and purification by flash chromatography (eluted with 8:10:1 EtOAc Hexanes: MeOH) to give 23 and 24.
[0188] 92 mg of 23 (0.21 mmol) in 3 mL of n-butanol is treated with 0.9 mL of 3-chlorobenzylamine and 1 mL of i-Pr 2 NEt at 100° C. for 16 hr, then cooled to room temperature, diluted with ethyl acetate and washed with saturated NH 4 Cl, H 2 O, brine, dried over MgSO 4 and concentrated. The crude product is purified by flash chromatography (eluted with 4:5:1 EtOAc:Hexanes:MeOH) to give 25.
[0189] Alternatively, as illustrated in Scheme 2, 280 mg of the free amine 22 (1.1 mmol) is treated with 0.25 mL of i-Pr 2 NEt and 200 mg of 6-imidazolyl-2,4-difluoropyrimidine (1.1 mmol) in THF at room temperature for 13 hr, then diluted with ethyl acetate and washed with saturated NH 4 Cl, H 2 O, brine, dried over MgSO 4 and concentrated. The crude product is purified by flash chromatography (eluted with 8:10:1 EtOAc:hexanes:MeOH) to give 26 (less polar product) and 27 (more polar product). Four hundred fifty milligrams of 27 (1.08 mmol) in 50 mL of THF or n-butanol is then treated with 1.7 g of 3-chlorobenzyl amine and 5 mL of i-Pr 2 NEt at 80° C. for 16 hr then diluted with ethyl acetate and washed with saturated NH 4 Cl, H 2 O, brine, dried over MgSO 4 and concentrated. The crude product is purified by flash chromatography (eluted with 6:12:1 EtOAc:hexanes:MeOH) to give 28.
[0190] 2-amino-1-methylbenzimidazole (5.15 g, 35 mmol) was added to a solution of trifluoro pyrimidine (4.40 g, 32.8 mmol) and iPr 2 NEt (5.9 mL, 34 mmol) in CH 2 Cl 2 . After 16 hr, the reaction mixture was concentrated to approximately 30 mL. The two regioisomers, 2-(2-amino-1-methyl benzimidazole)-4,6-difluoropyrimidine 29 and 4-(2-amino-1-methyl benzimidazole)-2,6-difluoro pyrimidine 30 were separated by silica gel chromatography (50-100% ethyl acetate in toluene). 2.04 g (23%) of the 4-substituted regioisomer and 2.17 g (25%) of the 2-substituted regioisomer were isolated.
[0000] 2-(2-amino-1-methylbenzimidazole)-4,6-difluoropyrimidine (29)
[0000] 1 H NMR (CDCl 3 , 300 MHz) δ8.38, d, 1H; 8.23 bs 7.22, dd 1H; 7.06, dd, 1H; 6.88, d, 1H; 6.38, s, 1H; 3.42, s, 3H.
[0000] 19 F NMR (CDCl 3 , 75 MHz) 39574 Hz.
[0000] 4-(2-amino-1-methylbenzimidazole)-2,6-difluoropyrimidine (30)
[0000] 1 H NMR (CDCl 3 , 300 MHz) δ8.65, bs, 1H; 8.40, bs, 1H; 7.04-7.22,m, 3H; 6.87, d, 1H; 3.31, s, 3H.
[0191] 19 F NMR (CDCl 3 , 75 MHz) 42596 Hz, 38829 Hz.
[0192] To 500 mg (0.55 mmol/g, 0.275 mmol) of resin-bound secondary amine 5 in triglyme (10 mL) was added 29 (143 mg, 0.55 mmol) and 0.154 mL of i-Pr 2 NEt (175 μL, 1 mmol). The resulting suspension was heated to 80° C. for 16 hr. The suspension was then filtered and the resin washed with DMF (5×) and CH 2 Cl 2 (5×). Bromophenol blue test was negative indicating complete reaction of the resin-bound secondary amine.
[0193] To 450 mg (0.248 mmol) of resin-bound fluoropyrimidine in DMSO (4 mL) was added 1-(3-aminopropyl)imidazole (1 mL). The suspension was heated to 100° C. for 16 hr. The suspension was filtered and the resin washed with DMF (5×) and CH 2 Cl 2 (5×). This was then dried in vacuo.
[0194] To 400 mg (0.21 mmol) of resin-bound trisubstituted pyrimidine was added 5 mL of a 1:1 solution of TFA/CH 2 Cl 2 . The resulting mixture was stirred for 2 hr at 25° C. and then filtered. The filtrate was concentrated in vacuo and the residue was purified by flash column chromatography (SiO 2 , elution with ethyl acetate) to give the pure trisubstituted pyrimidine 31. Data for 31: MS: m/z (relative intensity) 473.4 (M + +1, 100).
[0195] It should be understood that while this invention has been described herein in terms of specific embodiments set forth in detail, such embodiments are presented by way of illustration of general principles, and the invention is not necessarily limited thereto. Modifications and variations in any given material or process step will be readily apparent to those skilled in the art without departing from the true spirit and scope of the following claims, and all such modifications are included within the scope of the present invention.
TABLE 1 MW 534.63 578.73 577.75 564.70 466.65 566.72 544.63 420.49 432.50 448.59 448.59 548.66 421.52 396.90 383.47 456.52 416.52 362.45 424.45 524.52 560.69 460.62 489.42 462.61 440.50 473.70 448.56 506.67 548.64 463.64 463.64 520.69 478.66 578.73 424.57 506.67 556.75 524.64 415.94 578.73 480.63 394.88 536.69 535.71 423.58 414.96 464.63 466.65 480.67 394.88 444.56 520.69 400.93 404.53 422.59 305.79 396.90 414.96 410.92 546.73 460.60 464.63 450.60 445.58 377.00 391.00 405.00 392.00 420.00 422.93 472.61 553.71 565.72 569.75 550.68 516.66 580.70 586.75 540.64 587.81 517.65 532.70 602.79 556.68 431.34 398.87 406.51 383.51 383.51 393.47 399.42 419.55 460.60 329.37 409.53 354.45 331.80 395.50 340.42 381.47 488.61 518.64 551.67 544.67 531.68 595.79 488.61 504.65 534.68 567.71 560.71 533.69 547.72 611.83 603.85 504.65 500.62 528.67 530.65 598.76 552.65 563.68 556.68 529.66 543.69 607.80 500.62 439.97 410.92 446.57 405.52 419.55 460.60 389.26 355.46 394.88 515.03 482.95 488.6 463.52 491.53 523.6 548.64 546.7 410.94 449.55 470.41 449.57 448.57 578.77 464.63 544.63 423.54 423.54 489.38 596.75 566.72 359.45 626.77 645.61 478.00
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Compounds that selectively inhibit inappropriate kinase activities and methods for their preparation are disclosed. In one embodiment, the compounds are represented by Formula I,
As selective inhibitors of inappropriate kinase activities, the compounds of the present invention are useful in the treatment of conditions associated with such activity, including, but not limited to, inflammatory and autoimmune responses, diabetes, asthma, psoriasis, inflammatory bowel disease, transplantation rejection, and tumor metastasis. Also disclosed are methods of inhibiting inappropriate kinase activities and methods of treating conditions associated with such activities.
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BACKGROUND OF THE INVENTION
This invention relates to a resist printing method utilizing different reactivities of reactive dyestuffs, and particularly relates to a resist printing method for vinyl sulfone type reactive dyestuffs.
Reactive dyestuffs have been used preferably for a fast color dyeing of such materials as polyamide synthetic fiber, wool, cotton, hemp, viscose rayon, cuprammonium rayon and cellulose acetate. The use of such reactive dyestuffs for a fast color dyeing sometimes has required a resist printing. However, since an acid material, such as tartaric acid, is used as a resist in the prior art, alkali materials contained in a reactive dyestuff composition as an essential element, are neutralized. This neutralization of the alkali materials prevents development of every reactive dyestuff. Consequently, white resist printing can be achieved but color resist printing cannot be carried out with the combination of plural reactive dyestuffs. Accordingly, the aforementioned prior art method is not substantially useful.
A colored resist printing method is disclosed in Japanese Patent Publication No. 12,877 of 1969, in which alkali hydroxymethanesulfonate was used as a resist printing agent for vinyl sulfone type reactive dyestuffs to make the combination of reactive dyestuffs useful in a colored resist printing. However, the dyestuffs used in this method are limited and this method cannot be applied to the resist printing for dark colored dyestuffs such as black and dark blue. Further, if the printed pattern of the resist printing paste is allowed to stand or dried, a good resist effect is not expected. Accordingly, the resisted dyestuff must be applied subsequently to print the resist printing paste without drying. This is a problem in workability.
An object of this invention is to provide a new method for resist printing with use of reactive dyestuffs.
Another object of this invention is to provide a method for resist printing which effectively prevents development of the dark colored reactive dyestuffs.
A further object of this invention is to provide a method for resist printing which is superior in workability.
SUMMARY OF THE INVENTION
In this invention the development or fixation of a vinyl sulfone type reactive dyestuff in a fibrous material is prevented with the use of a resist printing paste comprising at least one compound which has the following general formula: ##STR3## wherein R 1 is hydrogen, an alkyl group or an aryl group, R 2 is an alkyl group, an aryl group, ##STR4## and X is an alkali metal or an amine.
The compound having the formula (I) is easily produced by the addition reaction of an aldehyde or ketone such as acetaldehyde, butylaldehyde, benzaldehyde, glyoxal, malonaldehyde, acetone, methyl ethyl ketone and acetophenone with an acid alkali sulfite or acid amine sulfite as indicated in the following reactions: ##STR5## The chain length of R 1 and R 2 is not limited, but the preferable alkyl group is that having 1 to 6 carbon atoms and the preferable aryl group is phenyl or phenyl derivatives. As X, there are preferably included sodium, potassium, lithium and tertiary amine, selected from the group consisting of trialkyl amines, trialkanol amines and alkanol amines whose alkyl or alkanol group has 1 to 4 carbon atoms, respectively.
DETAILED DESCRIPTION OF THE INVENTION
In this invention, compound (I) is admixed with a paste to prepare a resist printing paste. The resist printing paste is printed to a fibrous material and then a dye liquid or paste comprising a vinyl sulfone type reactive dyestuff is applied to the resist printed fibrous material whereby the development of the vinyl sulfone type reactive dyestuff printed on the resist printing paste is prevented. According to the invention the reactivity of compound (I) with vinyl sulfone type reative dyestuffs is utilized. Since compound (I) is easily reacted with vinyl sulfone type reactive dyestuffs, the vinyl sulfone type reactive dyestuff printed on the resist printing paste is reacted thoroughly with compound (I) prior to reaching the surface of the fibrous material. As a result, the vinyl sulfone type reactive dyestuff cannot be developed and fixed to the fibrous material. Thus a superior resist printing is attained in the invention.
The content of compound (I) in the resist printing paste is freely selected. Generally, one % by weight of compound (I) is preferably contained and 2 to 3% by weight of compound (I) is more preferably.
Compound (I) hardly reacts with dyestuffs other than from vinyl sulfone type reactive dyestuffs and if compound (I) is reacted with such other dyestuffs the reaction is very slow. Accordingly, the resist printing paste according to the invention is very useful for either white resist printing or colored resist printing. The colored dyestuffs included in the resist printing paste are not particularly limited. Compound (I) does not substantially prevent the reactivity of monochlorotriazine, trichloropyrimidine and dichloroquinoxaline dyestuffs, reactive dyestuffs similar to vinyl sulfone type dyestuffs, the development of the vinyl sulfone type dyestuffs being prevented with compound (I). So the resist printing paste according to the invention preferably comprises at least one of these reactive dyestuffs to produce a clear colored resist printing.
Further, since compound (I) is superior in heat stability and is stable to drying, a vinyl sulfone type reactive dyestuff can be applied to the printed fibrous material with the resist printing paste in the invention either after or before drying the paste. If a vinyl sulfone type dyestuff is applied after drying the resist printing paste at 100° C. to 150° C., the resist printing is carried out very effectively. Further, as compound (I) is very reactive, the resist printing paste according to the invention can prevent the development or fixation of all vinyl sulfone type dyestuffs including dark and light colored dyestuffs. Accordingly, the method of the invention is superior in workability and has extensive applications.
PREFERRED EMBODIMENTS OF THE INVENTION
The following examples are given in order to illustrate the invention without limiting the same. Unless otherwise indicated, the amounts of the components are designated in parts or % by weight.
EXAMPLE 1
30 Parts of Kayacion Yellow-4G(manufactured by Nippon Kayaku Co., Ltd.) and 50 parts of urea were dissolved in 170 parts of hot water and then mixed with 500 parts of 5% sodium alginate to form a first mixture. To the first mixture, 10 parts of sodium-m-nitrobenzenesulfonate and 20 parts of sodium hydrogen carbonate were added and admixed uniformly to form a second mixture. Subsequently, 20 parts of glyoxal-acid sodium sulfite dissolved in 200 parts of hot water were added to the second mixture to obtain 1000 parts of a homogeneous printing paste (A 1 ).
On the other hand, 70 parts of Remazol Black B (manufactured by Hoechst Aktiengesellshaft) and 50 parts of urea were dissolved in 350 parts of hot water, and mixed with 500 parts of 5% sodium alginate. To the mixture 10 parts of sodium m-nitrobenzenesulfonate and 20 parts of sodium hydrogen carbonate were added and admixed homogeneously to prepare 1000 parts of a printing paste (B 1 ).
The paste (A 1 ) was printed on a cotton broad cloth and then the paste (B 1 ) was printed on the cotton broad cloth so that the printed pattern of the paste (A 1 ) was partly covered with the paste (B 1 ). The printed cloth was steamed at 100° C. for 10 minutes, rinsed with water and then with warm water, soaped and rinsed with water. There was obtained a good printed cloth in which a yellow pattern and a black pattern were distinguished respectively without admixing the colors in the part of which the black paste (B 1 was printed on the yellow paste (A 1 ).
EXAMPLE 2
Example 1 was repeated except that the cloth printed with the paste (A 1 ) was dried at 100° C. prior to the printing with the paste (B 1 ). A printed cloth superior in resist printability was obtained as in Example 1.
According to Examples 1 and 2, it is found that glyoxal-acid sodium sulfite could be effectively used for resist printing in the state of either wet or dry.
EXAMPLE 3
Example 1 and Example 2 were repeated with the use of seven compounds indicated in Table I instead of glyoxal-acid sodium sulfite adduct to examine the resist-printability and the heat resistance of each compound.
TABLE I.______________________________________ Resist-Compounds print- HeatNo. General formula R.sub.1 R.sub.2 ability resistance______________________________________ ##STR6## H CH.sub.3 ○ X2 H C.sub.4 H.sub.9 ⊚ ○3 H ##STR7## ⊚ ○4 CH.sub.3 CH.sub.3 ○ ○5 CH.sub.3 C.sub.2 H.sub.5 ⊚ ○6 CH.sub.3 ##STR8## ⊚ ○7 H H X X______________________________________ Resist-printability: tested for Remazol Black B (manufactured by Hoechst Aktiengesellshaft). ⊚-very good ○-good X bad Heat resistance: acceptability of heat drying step each compound. ○-superior in resist printability in the state of either wet or dry. Xbad in resist printability after drying other resist printing paste.
EXAMPLE 4
30 Parts of Cibacron Brilliant Red BD (manufactured by Ciba-Geigy Corporation) and 150 parts of urea were dissolved in 180 parts of hot water and then mixed with 500 parts of 5% sodium alginate. To the obtained mixture 10 parts of sodium m-nitrobenzenesulfonate and 20 parts sodium hydrogen carbonate were added. A solution of 10 parts of benzaldehyde-sodium hydrogen sulfate adduct in 100 parts of hot water was then added to the obtained mixture to prepare 1000 parts of a homogeneous paste (A 2 ).
30 Parts of Remazol Brilliant Blue R (manufactured by Hoechst Aktiengesellshaft) and 150 parts of urea were dissolved in 290 parts of hot water and admixed with 500 parts of 5% sodium alginate. Further, 10 parts of sodium m-nitrobenzene sulfonate and 20 parts of sodium hydrogen carbonate were added to the mixture to prepare 1000 parts of a printing paste (B 2 ).
The paste (A 2 ) was printed on a cotton satin cloth and then the paste (B 2 ) was printed on the cloth so that a part of the printed pattern of the paste (A 2 ) was covered with the paste (B 2 ). The printed cloth was dried at 150° C. for 3 minutes, rinsed with water and then warm water, soaped and rinsed with water. As a result, there was obtained a clear colored satin having a blue area containing a red inset.
EXAMPLE 5
Example 4 was repeated except to use seven compounds indicated in Table II instead of benzaldehyde-sodium hydrogen sulfite adduct to examine the resist-printability and the heat resistance of the compounds. The heat resistance was examined in the same manner as Example 4, in which the cloths were dried after printing the paste (A 2 ).
TABLE II.______________________________________ Resist- HeatCompounds print- resis-No General Formula R.sub.1 R.sub.2 ability tance______________________________________ ##STR9## H CH.sub.3 ○ X2 H C.sub.4 H.sub.9 ⊚ ○3 H ##STR10## ⊚ ○4 CH.sub.3 CH.sub.3 ○ ○5 CH.sub.3 C.sub.2 H.sub.5 ⊚ ○6 CH.sub.3 ##STR11## ⊚ ○7 H H X X______________________________________
EXAMPLE 6
30 Parts of Cibracon Scarlet RP (manufactured by Ciba-Geigy Corporation) and 50 parts of urea were dissolved thoroughly in 180 parts of hot water and then mixed with 500 parts of 5% sodium alginate. To the obtained mixture, 20 parts of sodium m-nitrobenzenesulfonate and 20 parts of sodium hydrogen carbonate were added and further 40 parts of sodium hydroxymethanesulfonate and 10 parts of glyoxalacid sodium sulfite were added to obtain 1000 parts of a homogeneous printing paste (A 3 ).
70 Parts of Remazol Black B (manufactured by Hoechst Aktiengesellshaft) and 50 parts of urea were dissolved in 350 parts of hot water and admixed with 500 parts of 5% sodium alginate. To the obtained mixture 10 parts of sodium m-benzenesulfonate and 20 parts of sodium hydrogen carbonate were added to prepare a homogeneous printing paste (B 3 ).
The paste (A 3 ) was printed on a cotton broad cloth and then the paste (B 3 ) was printed on the cotton broad thoroughly. After drying the printed cloth was steamed at 100° C. for 10 minutes, rinsed with water and then warm water, soaped and rinsed with water to obtain a black cloth containing a clear red inset.
EXAMPLE 7
20 Parts of glyoxal-acid triethanolamine sulfite adduct was dissolved in 480 parts of hot water and admixed with 500 parts of 5% sodium alginate uniformly to prepare a printing paste (A 4 ).
The paste (A 4 ) was printed on a cotton satin cloth and then the paste (B 1 ) prepared in Example 1 was printed on the satin cloth thoroughly. After drying the satin cloth was steamed at 100° C. for 10 minutes, rinsed and after-treated to obtain a black cloth containing a clear white design.
EXAMPLE 8
Example 6 was repeated except to use the following three compounds instead of glyozal-acid sodium sulfite;
glyoxal-acid tributylamine sulfite adduct,
benzaldehyde-acid diethanolbutylamine sulfite adduct and
benzaldehyde-acid tripropylamine sulfite adduct.
There were obtained black cloths containing a clear red inset as in Example 6.
EXAMPLE 9
Example 7 was repeated except to use the following three compounds instead of glyoxal-acid triethanolamine sulfite adduct:
glyoxal-acid tributylamine sulfite adduct,
benzaldehyde-acid diethanolbutylamine sulfite adduct and
butylaldehyde-acid tripropylamine sulfite adduct.
There were obtained white resist printed cloths superior in whiteness.
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This invention relates to a resist printing method utilizing of different reactivities of reactive dyestuffs. The development or fixation of a vinyl sulfone type reactive dyestuff in a fibrous material is prevented with the use of a resist printing paste comprising at least one compound which have the following general formula: ##STR1## wherein R 1 is hydrogen, an alkyl group or an aryl group, R 2 is an alkyl group, an aryl group, ##STR2## and X is an alkali metal or an amine.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a Continuation-In-Part of the prior application under the Ser. No. 09/656,919 filed on Sept. 07, 2000.
BACKGROUND TO THE INVENTION
[0002] The invention relates to a pile repair jacket form being useful in repairing bridge, pier or walkway supports that are submerged in a body of water or above the ground. Walkways such as piers or boardwalks are supported over a body of water or above the ground by way of piles that have been driven into the bottom of the body of water below the mud line or simply into the ground. Such piles can consist of concrete, timber and steel. It is obvious that the concrete, timber and steel piles are subject to corrosion or deterioration because of being permanently located in a water environment. Concrete piles are subject to corrosion, especially if the steel re-bars located therein are subject to rusting if they are located too close to the outer surface of the concrete pile or are exposed altogether. The timber piles are always pressure treated against corrosion or deterioration but the time span of their useful life is substantially shortened when the timber piles are located in a body of water. Steel piles are water proofed prior to their installation but over a period of time the water proofing is not durable or protective enough to protect the steel from corroding.
[0003] Most of the damage in all of the above supporting piles occurs at the water line because of the wave action. This wave action is further aggravated by the tides which are prevalent at most installations. In many installations, the high tide covers a greater height of the pile, while at a low tide, a greater length of the pile is exposed to the environment. Therefore, the piles undergo drying and wetting cycles which tend to eat away at the pilings, especially the wooden piles, thus weakening the piles mostly at their mid sections of their total length. Also, water insects like marine borers tend to accelerate the above noted deterioration and are the leading cause of timber pile deterioration. The above noted problems are not as prevalent with support piles that have been driven into the ground, mainly to support buildings or houses. It is noted that, especially at shore lines, houses or dwellings are supported on so-called stilts. These stilts are subject to some wave action, especially at high tides but are normally kept out of the water action. If not subjected to any water action, the corrosive and salty air does contribute to a corrosive action and thereby destroying action over a longer period of time. The support piles can be repaired in situ without having to remove the supported superstructure.
[0004] Many devices have been used to repair the above noted damages short of replacing the pilings altogether. This tends to substantially increase the cost of such an installation.
[0005] The DENSO™ North America Corp. teaches the use of fiber form jackets that are placed over the whole length of the pile to be repaired or over the damage at the tidal zone. The jacket is made of fiber glass and therefore has some flexure in the material, especially over greater lengths. Because of its ability to flex, the jackets can be installed at the desired location without having to disassemble the superstructure above the piles. Once in place, the jackets at their longitudinal open edges have a tongue and groove arrangement to close and seal the longitudinal edges. Bandings are placed around the jacket at about every 12″. Also standoffs between the pile and the interior surface of the jacket should be used to increase its stability. The use of fiberglass material is very expensive.
[0006] Another suggested use is demonstrated by the above noted corporation and that is the use of a fabric form jackets. The fabric form jacket is made of 100% continuous multifilament NYLON fibers and is placed around the damaged area of the pile and the top and the bottom is then closed against the pile by banding. A longitudinal zipper is then closed to complete a cylindrical enclosure. A disadvantage with this kind of an arrangement is that the cylindrical fabric form does not have a form stability in that when the concrete fill is inserted therein, it has a tendency to collect more concrete in the bottom of the cylinder and less at the top, whereby a pear-shaped form is assumed. Therefore, more concrete has to be used than is necessary. Hydraulic concrete is quite expensive. Also, the fabric form pile jacket itself is quite expensive.
[0007] A similar jacket system is disclosed by the ROCKWATER Corp. in Farmingdale N.Y. They disclose fiberglass reinforced pile jackets under the name of ROCKFORM™ F and a nylon Pile Jacket under the name of ROCKFORM™ N. As a matter of fact, there is an illustration in their brochure showing the nylon jacket installed on a pile after having been filled with concrete. This illustration clearly demonstrates the disadvantage of this type of a repair wherein more of the concrete is located in the bottom of the bag instead of being equally distributed throughout the length of the bag, as was enumerated above already.
[0008] Another form jacket is disclosed by the DESLAURIERS, Inc. company. The disclosed jacket consists of two halves that have to be bolted together at their respective flanges and therefore can be installed around existing piles without having to disturb the decking which is supported by the same. However, the assembly underwater is quite cumbersome, expensive and time consuming.
OBJECTS OF THE INVENTION
[0009] According to the invention, applicant is using a high density polyethylene HDPE pipe, which pipe has a smooth interior wall and an annular corrugated exterior for strength. This pipe is manufactured by the Advanced Drainage Systems, Inc. of Columbus, Ohio. High Density Polyethylene is an extremely tough material that can easily withstand the normal impacts involved in shipping and installation. The proposed applications for this pipe have been specified for culverts, cross drains, storm sewers, land fills and other public and private constructions. There is no proposal to use these pipes for repairing pile supports above water or below.
[0010] The pipe, as is, could be used for that purpose but only after the decking, which is supported by the pile, has been removed, and then the pipe could be slipped over and along the pile. However, this pipe cannot be used as a jacket in sections above and below water without first removing the decking or superstructure. In the inventive concept, the pipe has been modified for this purpose by cutting through the pipe longitudinally first. This cutting alone will not suffice because the annular corrugations prevent the pipe at its longitudinal cut to be opened to such an extent and size so that the jacket can easily be slipped around a damaged pile. The corrugations are of such a size and strength so as to not allow any such movement. To accommodate a proper opening, the casing or jacket has been cut in a V-shape and only through the corrugations and opposite the longitudinal cut but not into the wall itself that supports the corrugations and forms the interior smooth surface, thereby creating a live hinge. The HDPE material is flexible enough to allow repeated openings and closings of the jacket along its live hinge without breaking or separating. The corrugated pipe is readily available in diameters from 4 inches to 48 inches and therefore lends itself to many applications including in square concrete pile applications. The pipe also is available in various lengths which enhances the installation possibilities under water. If various lengths have to be assembled, the various sections can be supplied with bell- and spigot ends that fit well within each other including various seals between the sections.
[0011] As will be explained in more detail below, the pipe is normally delivered in a black color. It is also desirable to have the pipe made of an opaque material. This material allows for a view into the interior of the jacket when it is being filled with concrete. When filling a long pipe or tube with concrete, it can happen that voids form within the concrete especially at the inner wall of the pipe. If not corrected, this would leave voids in the formed concrete which would effect the quality and the performance of the installation. An opaque material allows a visual observation of the pouring of the concrete and observed flaws can immediately be corrected.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] [0012]FIG. 1 is a perspective view of the pile repair jacket;
[0013] [0013]FIG. 2 is a perspective view of the jacket installed on a pile to be repaired;
[0014] [0014]FIG. 2A is a perspective view of an alternative seal;
[0015] [0015]FIG. 2B is a perspective view of still another alternative seal;
[0016] [0016]FIG. 3 is a somewhat different embodiment of FIG. 2;
[0017] [0017]FIG. 3A shows a different seal for the edges of the jacket;
[0018] [0018]FIG. 4 illustrates a construction of closing the edges of the jacket;
[0019] [0019]FIG. 5 shows a bell and spigot arrangement of connecting two units;
[0020] [0020]FIG. 6 illustrates an installation of the jacket within a tidal zone;
[0021] [0021]FIG. 7 is a top view of a modified jacket form of FIG. 1;
[0022] [0022]FIG. 8 is a perspective view of a modified edge connection;
[0023] [0023]FIG. 9 is a detailed view of a modified connection.
DETAILED DESCRIPTION OF THE INVENTION
[0024] [0024]FIG. 1 illustrates the invention of the pile repair jacket as it has been modified from what is known in the prior art. The jacket is being identified as 1 . The jacket 1 normally has a solid but somewhat resilient and circumferential wall forming a cylinder. Around the cylindrical wall a multiple of corrugations 3 are formed or molded to give the jacket a strong rigidity. The cylinder is being cut in a longitudinal direction to expose longitudinal edges 4 . Opposite from the longitudinal edge 4 a V-shaped cut is made into the corrugations but only onto the straight cylindrical to maintain its integrity. This is shown at 6 . The jacket 1 has a smooth interior wall 7 and an upper edge 2 . This way a live hinge 8 is created by virtue of the wall being somewhat flexible because of the loss of the corrugations 3 at that particular point 8 . It is now apparent that the former rigid cylinder may now be opened up so that it can be draped around a timber pile that is in need of a repair. If any larger diameter piles or supports within a body of water needs to be repaired, it is quite possible to cut at least three V-shaped cuts into the corrugations 3 down to the smooth wall so as not to over stress any individual live hinge in case that the jacket has to be opened rather wide to surround a large pile support such as could happen with square concrete piles. Once the jacket has been installed around a pile, the edges 4 have to be brought together again and sealed against each other. Therefore, a self-adhesive seal 5 has been provided between the edges 4 which will seal against water leaking into the jacket or concrete leaking out at a later time when the jacket is filled with concrete. The adhesive seal may consist of a soft foam rubber or some other flexible rubber. The seal is adhesive at least on one side so that it will firmly adhere to at least one of the edges 4 and cannot be dislodged.
[0025] [0025]FIG. 2 illustrates the jacket 1 after it is installed around a damaged area of the pile P. Like reference characters have been applied to like elements as explained in FIG. 1. In order to stabilize the interior wall against the pile P, standoffs 9 have been provided which are merely nailed into the pile P. The standoffs have been shown as U-shaped but can take many other forms. It is also noted that the standoffs should be made of a plastic material or other non-corrosive material, because if it is too close to the surface, once the concrete is cast and is cured, the standoff if it is made of metal, could be a cause for corrosion and/or rusting. In order to bring the outer circumference of the jacket 1 back into its original circular shape, the edges 4 are pulled together by banding 10 which will settle in annular grooves between the annular corrugations 3 . The banding 10 shown in FIG. 2 is of the conventional ratchet type otherwise known as hose clamps in automobile engines, for example. The banding 10 is tightened within the groove by ratchet screw 10 a which is well known. The seal 5 is shown as self-adhering to one of the edges 4 . When the banding 10 is applied to the jacket 1 , the seal 5 may have to applied with a notch 5 a so that the banding 10 will not disturb the shape of the rectangular seal 5 .
[0026] [0026]FIG. 2A illustrates another seal 11 which is not self-adhering but instead is supplied with plugs 11 a which are formed in such a shape so that will snugly fit within the interior openings of the corrugations 3 . This type of an arrangement will assure a longer lasting fit and could be reusable, while a self-adhering seal 5 will have a one time use only.
[0027] [0027]FIG. 2B illustrates still another seal 26 which has plugs 26 a and 26 b on both sides of the rectangular seal 26 . Additionally, the rectangular is somewhat enlarged so that it will extend into the interior of the jacket form 1 . The extension into the interior of the jacket form has lateral holes 26 c therein. When the jacket form 1 is being filled with concrete, the concrete will migrate into these holes to completely fill the same. Of course, the soft rubber seal of FIG. 2A would not be practical in this type of installation. It is preferred that the same material by used in this instance as was used to manufacture the jacket form 1 such as HDPE. All other seals disclosed above could have the same interior extensions as shown in FIG. 2B. This type of installation makes a very rigid fastening system.
[0028] Turning now to FIG. 3, there is shown a similar jacket 1 of FIG. 2 but with some preferred modifications It is clear that when installing a jacket 1 around a pile P that there always should be at least two bandings 10 . Another type of banding is shown at 13 . This banding is also well known. It is made of a plastic material and has a non-reversing or one-way buckle 14 . FIG. 3 also illustrates the use of form-fitting plugs 12 which are pressed into the interior of each of the corrugations of one of the edges and are received in the same manner in the other interiors of the other corrugations of the other edge. This will assure a rigid fit between the longitudinal edges 4 of the jacket 1 . These plugs also help in locating the edges 4 relative to each other in a self-aligning manner when the jacket is installed. After all, the assembly takes place in an underwater environment and the visibility might be hampered.
[0029] [0029]FIG. 3A shows a different seal 15 to be used between the edges 4 when they are closed. This seal 15 is a rectangular seal but having openings 15 a therein to accommodate the plugs 12 there through when the plugs 12 enter the openings in the corrugations.
[0030] Turning now to FIG. 4 which shows a different fastening system for closing the jacket onto its edges 4 . This fastening system consists of a buckle system 16 of the over center type. To this end, the buckle 16 includes two plates 17 and 19 which are riveted by rivets 17 a and 19 a, respectively, to the top or outside surfaces of the respective corrugations 3 . Plate 17 has a longitudinal hasp 18 mounted thereon which is pivotal around pivot 18 a. The other plate 19 has a pivotal handle 20 mounted thereon which is pivotal around pivot 20 a. The handle 20 also carries a hook 21 thereon. When it is desired to lock the two edges 4 of the jacket together including the seal 5 , the hasp 18 is placed within the hook 21 on handle 20 and the handle 20 is then moved to a closed position, as shown in FIG. 4, whereby the hook 21 pulls the hasp 18 and thereby the edges 4 together until the hook 21 is pulled past the pivot 20 a which position is over the center of the buckle system 16 . This assures a secure lock. Of course, two such buckle systems need to be used, one at the top of the jacket and a second one at the bottom. The advantage is this type fastening system is that it can be used repeatedly in many different installations. Another advantage resides in the fact that no tools are required to lock the edges 4 together which greatly enhances the use in an underwater assembly. Another advantage lies in the fact that this installation can be a one man operation. All of the above lessens the cost of the installation and the assembly is quicker to perform.
[0031] [0031]FIG. 5 illustrates how two jackets are connected together through the use of a bell and spigot system. Lines and arrow I denote the lower section of the upper jacket, while lines and arrow II denote the upper section of the lower jacket. The lower section of the upper jacket has an extension or bell S which overlaps the first two annular corrugations of the upper section of the lower jacket. For this purpose, the two annular corrugations 3 a and 3 b are somewhat reduced in circumferential size so that the extension S can slip over the same. The corrugation 3 a also has the seal 25 embedded in its outer surface to assure a tight seal between the two jackets.
[0032] [0032]FIG. 6 illustrates a complete installation of the jacket on a limited extent of the underwater pile P. Any installation contemplated above ground would follow the same assembly steps. In the previously described jackets, above, it was assumed that the jacket would completely cover the pile P all the way to and below the mud line of the body of the water. FIG. 6 only repairs or rehabilitates only part of the pole P. It is a well known fact that most of the damage to a timber pile occurs at the wave line W and within the tidal zone T. The corrosion has been indicated by C. To this end, a jacket 1 is installed over the deteriorated section C and is stabilized laterally by standoffs 9 . The bottom of the jacket is stabilized relative to the height of the pile P by spikes 23 driven into the pile or otherwise fastened to the pile. In order to completely close the bottom of the jacket 1 against the loss of concrete, a Nylon fabric bag 24 is installed. The bag 24 is banded within a valley of the last corrugations 3 of the jacket 1 through the use of banding 24 a and the lower end of the bag is banded against the pole P itself through the use of banding 24 b. The numeral 22 indicates a port for the entry of concrete. It is a known fact that concrete should be introduced into the interior of the jacket at a bottom thereof. This will force the water therein upwardly and furthermore avoid air bubbles from forming within the concrete.
[0033] Turning to FIG. 7, there is shown a repair jacket form having at least three V-shaped cuts 6 , 6 a and 6 b made through the corrugations 3 . In some repair undertakings, larger piles in circumference are encountered including square concrete piles that require the repair jacket form to be opening rather wide. This might over stress the material tolerance of just a single live hinge. Therefore the presence of three live hinges 6 , 6 a and 6 a will considerably alleviate this overstressing.
[0034] [0034]FIG. 8 illustrates a different system of connecting the edges of the jacket 3 together. It has been found that when long or tall columns are being used and when they are filled with concrete, the lower end of the column, especially at their edges does not want to stay tong because of the accumulated weight of the concrete. This problem is being alleviated through the use of the connectors 30 and 31 shown in both FIGS. 8 and 9. The connectors 30 and 31 can easily be extruded from a plastic material of the same composition from which the jackets are made. The connectors can easily be fastened to the inside surface of the jacket 3 by fasteners shown in FIG. 8. As can be seen in FIG. 8, the female connector 30 is installed with its socket edge flush with the edge of the jacket. The male connector 31 is installed with its projecting part protruding from its base and is ready to be received within the female socket of connector 30 . In this manner, both opposing edges of the jacket will be abutting each other and will be form-fitting.
[0035] Turning now to FIG. 9, the structural details of the connectors 30 and 31 are shown. The male as well as the female are double serrated and the serrations are opposing each other, Once the serrations are inserted into each other they will form a planar surface facing at the interior of the jacket. Experiments have shown that this type of connector solves the problem of the jacket edges opening at any length or regardless of the weight of the concrete.
SUMMARY OF THE INVENTION
[0036] From all of the above, it can now be seen that the repair or rehabilitation of an underwater as well as an above ground support pile has greatly been simplified with a lower cost realization. The jacket forms disclosed herein can be reused many times over or the jacket forms can be left in situ which may prolong the life of the installation indefinitely. The installation has been simplified and speeded up to thereby save cost in labor. These were the objects of the invention.
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The invention relates to a plastic jacket that is used for repairing underwater or on ground support piles that have been corroded by the wave action at the waterline, by a tidal zone or natural salty air corrosion, respectively. The jacket consists of a cylindrical wall having annular corrugations on its exterior surface. The cylindrical wall has a longitudinal cut along its length to exhibit two opposing edges. A seal is placed between the opposing edges. Opposite from the longitudinal cut there is a V-shaped cut through the corrugations to the cylindrical wall to create a living hinge in the plastic material of the wall. Banding is provided to pull the opposing edges into a tight relationship and trapping the seal there between. The V-shaped cuts enable the jacket to be opened and placed around a damaged pile in spite of the corrugations which would prevent such an opening. It is preferred that the material of the jacket be made of an opaque material. This way, when any flaws, such as voids, develop within the poured concrete they can be observed through the opaque material and can be eliminated or corrected immediately.
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REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the priority date of German application DE 103 27 621.1, filed on Jun. 18, 2003, the contents of which are herein incorporated by reference in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates to a circuit arrangement having a circuit which operates continuously in the time domain on the basis of the Σ-Δ principle.
BACKGROUND OF THE INVENTION
[0003] Modern digital technology allows signals to be handled much more easily in digital form than in their analog form. However, it is necessary to convert the received analog signals which are to be handled into their digital form beforehand. Conversely, a digital signal must first be converted into an analog signal before it can be transmitted. For the conversion, “analog/digital converters” or ADCs and the corresponding counterpart DACs for digital/analog converters are used.
[0004] So as not to suffer any loss of information when converting an analog signal into a digital signal, the analog signal needs to be sampled, on the basis of the Nyquist criterion, at a frequency which is greater than twice the maximum analog frequency which occurs. At the same time, repetition spectra arise at the multiple of the sampling frequency during sampling. These repetition spectra need to be heavily suppressed as appropriate by a filter.
[0005] If the sampling frequency corresponds exactly to the Nyquist criterion, then the sampled spectrum is adjoined by the repetition spectrum directly. Hence, a filter having an almost infinitely high edge gradient is required, which cannot be produced in practice. A sampling rate at a much higher frequency than the Nyquist frequency results in a greater distance between the repetition spectra and allows the use of lower order filters of lesser quality and hence with lower edge gradients.
[0006] An analog/digital converter now ascertains the amplitude of the analog signal at a sampling time and converts it into a digital value. In this case, the analog/digital converter divides a maximum amplitude value into subranges of essentially the same magnitude which correspond to the number of bits in the analog/digital converter. By way of example, a maximum occurring voltage amplitude of 1 V is thus divided into 16 stages of 0.125 V each in a 16-bit analog/digital converter.
[0007] The analog amplitude signal is compared with the reference values, which assigns an appropriate digital signal. The maximum quantization error is thus half of the difference between two digital reference values, that is to say 62.5 mV in the example. The more precise the division, therefore, the smaller becomes the discrepancy between the result and the analog real value.
[0008] One particular embodiment of an analog/digital converter, which is used in digital communication appliances particularly on account of its relatively small demands on the analog suitability of the technology used, is the continuous-time Σ-Δ modulator shown in FIG. 5 . This does not convert the analog amplitude signal into a discrete digital value at a sampling time, but rather samples the analog value continuously in the time domain, minimizes the mean-error error over a large number of sampling times, and simultaneously performs filtering (generally high pass filtering) on the quantization errors, which are also called quantization noise.
[0009] In this case, the sampling frequency is many times higher than the necessary Nyquist frequency, which means that reference is made to “over sampling” in a general way here. The comparison circuit, the comparator CP in the Σ-Δ modulator shown in FIG. 5 , has a signal applied to its input E at one time. This signal is compared with a reference signal at the inverting input of the comparator CP, which means that the comparator outputs a positive or negative binary state at the output.
[0010] This signal is firstly processed in a digital decimator and filter DF and is secondly returned to the input of the Σ-Δ modulator via a digital/analog converter DAC. The digital/analog converter DAC converts the digital signal from the comparator into an analog signal using a reference voltage U REF and supplies this analog signal to the input V IN such that the difference between the input signal and the returned signal is formed as a result. This difference signal is integrated and hence averaged in the integrator 3 and is supplied to the input E of the comparison circuit CP again.
[0011] The digital decimator DF performs a plurality of tasks. In that part of the Σ-Δ modulator's circuit which is upstream thereof, the quantization noise has not been eliminated, but rather has just been shifted to frequencies outside of the signal band. The first function in the decimator is therefore the filtering of this noise. When this noise has been eliminated, the clock rate can be reduced in the decimator without the risk of infringing the Nyquist theorem. At the same time as the clock rate is reduced, the word length is increased to a number of bits which corresponds at least to the resolution of the converter.
[0012] To increase the resolution, the number of integrators 3 can be increased further. This gives the noise transfer function a steeper gradient toward high frequencies, the noise suppression in the signal band being higher on account of the higher gain in the cascaded integrators. Put another way, markedly more effective filtering and hence a lower level of quantization noise in the signal band are achieved.
[0013] An example of a “fifth order” Σ-Δ modulator can be seen in FIG. 6 . The Σ-Δ modulator contains five integrating circuits, which are denoted by INT 1 to INT 5 . This Σ-Δ modulator is designed using gmC technology and, furthermore, its input V IN has a passive low pass filter which effectively attenuates at least high frequencies and thereby reduces the demands on the active circuit parts downstream.
[0014] The drawback of such continuous-time converters, however, is the dependency of the transfer functions and the resolution of time constants, which in ordinary production processes are subject to high levels of scatter of approximately 30%. These are both the usual parameter fluctuations on account of error tolerances in production and temperature responses. Secondly, in usual embodiments with switched current sources in the feedback path, the associated transfer function is dependent on fluctuations in the clock rate itself, known as jitter. In simplified form, jitter corresponds to nonequidistant zero crossings, caused inter alia by thermal noise in the clock generator's components, but also by radiated interference.
[0015] Since the integral of the returned signal, generally a current or charge signal, crucially determines the response of the circuit, any clock jitter which is present on the clock signal CLK is incorporated directly into the feedback signal. If, as is generally the case, the amplitude of the feedback signal is also much higher than the amplitude of the input signal, then the sensitivity toward clock jitter is increased even further.
[0016] Hence, the document “IEEE Transactions on Circuits and Systems—II: Analogue and Digital Signal Processing, vol. 49, No 11, November 2002: Highspeed Σ-Δ-Modulators with Reduced Timing Jitter Sensitivity” has proposed an arrangement which feeds a cosine square signal as the reference signal into the digital/analog converter DAC. This feedback pulse disappears at the sampling times T, which means that a small amount of clock jitter no longer matters. However, producing two symmetrical cosine signals was found to be extremely difficult and costly in practice.
[0017] Another proposal is the arrangement which is described in the document “2003 IEEE International Sold State Circuits Conference/Session 3/Oversampled A/D-Converters/Paper 3.4” and is shown in FIG. 6 . In this case, the feedback signal used is the charge which is stored on a switched capacitor. In FIG. 6 of the Σ-Δ modulator designed using gmC technology, these are the capacitors A. A capacitor is discharged in an exponentially decreasing current, which means that at the end of every clock period the current disappears and hence clock jitter no longer matters. A prerequisite for this is that, for the charging and discharging operation, the capacitor has a time constant which is significantly shorter than the corresponding charging and discharging period. In practice, a time constant which is up to eight times shorter, depending on the resolution of the converter 5 , than the corresponding charging and discharging period is generally sufficient.
[0018] In the arrangement shown in FIG. 6 , the forward transfer function is determined by the integrators. The determining variables are the values of the capacitors at the outputs of the gm blocks and also the gradients (gm values) of these blocks. These gradients in turn are determined by transistor parameters and by the reference currents in these blocks. The reference currents are usually derived from a bandgap voltage reference using a reference resistor. Ultimately, the forward transfer function is thus determined by R, C, a reference voltage and transistor parameters. The reverse transfer function, on the other hand, is determined by the charge transferred. This is dependent on the value of the capacitors A and also on the voltage to which these capacitors are charged. In the embodiment shown in FIG. 6 , the clock jitter plays no significant part, which was the aim of this circuit. The reverse transfer function is thus ultimately dependent on C and a reference voltage. However, this means that the absolute production variations in the resistors also result in a divergence (mismatch) between the two transfer functions.
[0019] The individual components therefore need to be proportioned such that the noise transfer function remains stable even for the most disadvantageous spread, which results in an increase in the noise and in losses in the signal-to-noise ratio, however. The demands for a high level of stability for the converter and simultaneously low noise with little clock jitter sensitivity cannot be met on the basis of this arrangement.
SUMMARY OF THE INVENTION
[0020] It is an object of the present invention to provide a continuous-time Σ-Δ modulator with an arrangement and a method which can be used to achieve improved stability for the time constants with simultaneously reduced jitter sensitivity for the converter.
[0021] The invention achieves this object by means of the features of the coordinate patent claims.
[0022] The invention provides a circuit arrangement having a circuit which operates continuously in the time domain on the basis of the Σ-Δ principle and which has at least one comparison circuit, an integrating circuit which has at least one integration element and which is characterized by a transfer function which is dependent on the integration element, and an apparatus for signal feedback.
[0023] The apparatus for signal feedback, which is connected to the output of the comparison circuit and to the input of the at least one integrating circuit, has a charge store for the purpose of feedback and is characterized by a transfer function which is dependent on the charge in the charge store. The charge store can be charged during a first period and can be discharged during a second period. The circuit arrangement has an alignment apparatus which can be used to align the two transfer functions.
[0024] Aligning the transfer functions, or the charge in the charge store, with the integration element which determines the time constant of the integrating circuit achieves a level of stability for the converter with a simultaneously low noise transfer function regardless of component spreads. The circuit arrangement is also independent of any jitter in the clock signal. It is thus possible to achieve a high level of stability for a circuit operating on the basis of the Σ-Δ principle while simultaneously having low quantization noise.
[0025] Further advantageous refinements are the subject matter of the subclaims.
[0026] It is thus expedient for the transfer function of the apparatus for signal feedback to be aligned with the transfer function of the integrating circuit by the alignment device by altering the charge on the charge store. This charge can easily be achieved by altering the voltage which is used during the charging operation for the charge store.
[0027] One particularly advantageous development of the invention is characterized in that the device has a load whose value and form are the same as those of the load which directly or indirectly prescribes the time constant of the integrating circuit's integration element. The device uses this load and uses a current mirror in order to impress a current into an arrangement, the voltage generated across the arrangement by the current controlling a feedback amplification device for charging the charge store in the apparatus for signal feedback.
[0028] In this case, it is expedient if the voltage generated across said arrangement is the same as the voltage for charging the charge store. One advantageous refinement of the arrangement is when it is in the form of an external resistor. It is naturally appropriate to produce this with particular precision. As a result, the voltage which is used to charge the capacitor is reciprocally proportional to the load which directly or indirectly prescribes the time constant of the integration element.
[0029] Alternatively, the arrangement is in the form of a first and, in parallel therewith, a second charge store having different capacities. The second charge store, which has a smaller capacity than the first charge store, can be connected to the first charge store and to a potential by means of two switches. It is advantageous if the second charge store is connected to the first charge store during the first period and to the potential during the second period.
[0030] Hence, a charge flows to the second capacitor in the first period and thus produces a voltage which can be used to control the charging voltage for the feedback capacitor. This charge can drain again during the second period. The first charge store, which is connected to the second charge store by means of a switch during the first charging period, compensates for any clock jitter there may be and hence for the dependency on the clock cycle. In this case, the influence of the clock jitter decreases by the square of the number of averaged cycles. The current mirror likewise means that the voltage generated through the capacitance of the charge store and of the flow of charge is reciprocally proportional to the load which prescribes the time constant of the integration element.
[0031] It is expedient for the charge stores to be in the form of capacitors and for the individual switches to be in the form of MOS transistors. It is likewise expedient for the current mirror to be produced using MOS transistors and for the feedback amplification device to be in the form of an operational amplifier. In this connection, it is advantageous if the voltage produced across the arrangement is the same as the voltage for charging the feedback capacitor.
[0032] In one development of the invention, the circuit arrangement is characterized by a first switch which can be used to isolate the apparatus for signal feedback from the output of the comparison circuit. In addition, the device has a second switch which can be used to apply a voltage to the input of the circuit arrangement. This voltage is the same as the charging voltage for the charge store in the apparatus for signal feedback.
[0033] This makes it possible to ascertain the difference between the charge or the current which flows through the load which prescribes the time constant during a particular period and the charge or the current on the charge store for the feedback. Compensating for this difference aligns the transfer functions with one another and hence reduces a systematic error and the noise.
[0034] In this connection, it is advantageous if the alignment device has a counting apparatus with a downstream digital/analog converter. The input of the counting apparatus is connected to the output of the comparison circuit, and the output of the digital/analog converter is connected to the input of the charge store for signal feedback. This allows the charging voltage for the charge store to be varied on the basis of the result of a measurement of the difference.
[0035] One alternative embodiment is characterized in that the device has at least one component resistance which can be switched into the signal path upstream of the comparison circuit on the basis of the result from the counting apparatus. This makes it possible to alter the value of the load which directly or indirectly prescribes the time constant of the integration element in the integrating circuit.
[0036] One advantageous embodiment of the integrating circuit is the design using RC technology. Alternatively, the integrating circuit is produced using gmC technology.
[0037] It is expedient for the voltage of the reference signal for the comparison voltage to be made the same as the voltage for charging the charge store in the apparatus for signal feedback.
[0038] A method for reducing an alignment error between a load in an integrating circuit which prescribes the time constant and a charge store for signal feedback, where the charge store is part of a feedback device is provided. The method includes measurement of a difference between the charge which flows through the load which prescribes the time constant during a period and the feedback charge which is supplied via the charge store during this period, and compensation for the difference.
[0039] Such difference measurement and the compensation allow accurate alignment of the forward transfer functions, which are dependent on the load which prescribes the time constant, with the reverse transfer function, which is dependent on the charge in the charge store. Besides the charge, it is likewise possible to measure the current which flows through the load and is provided by the charge store.
[0040] In one advantageous development of the method, the measurement is taken by applying a voltage having a first polarity to the load which determines the time constant of the integrating circuit. As a result, a defined charge or a defined current flows through the load during a particular period.
[0041] A voltage having the same magnitude and having the opposite polarity is used periodically to charge a charge store during a first period and to discharge it during a second period. The sum of these two charges or currents is a measure of the mismatch between the transfer functions of the charge store and of the load.
[0042] In one development of the invention, this measurement is taken a plurality of times, with the difference from a measurement being accumulated by the integrating circuit. This allows more precise measurement. The error per measurement is obtained from the quotient of the total error and the number of measurements.
[0043] Compensation may advantageously be performed by changing the load which prescribes the time constant. Alternatively, it is conceivable to perform compensation by changing the voltage which is used to charge the capacitor.
[0044] Another embodiment is the ascertainment of the number of supplied quantities of charge or current. In this context, a defined and quantized quantity of charge or current is supplied to the charge or current difference until the difference disappears. Advantageously, this quantity of charge or current can be supplied by the charge store in the feedback device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] The invention is explained in detail below with reference to the drawings, in which:
[0046] FIG. 1 shows a first exemplary embodiment of the invention,
[0047] FIG. 2 shows a second exemplary embodiment of the invention,
[0048] FIG. 3 shows a third exemplary embodiment of the invention,
[0049] FIG. 4 shows a timing diagram with a clock cycle,
[0050] FIG. 5 shows a known embodiment of a continuous-time Σ-Δ modulator,
[0051] FIG. 6 shows a known embodiment of a fifth order continuous-time Σ-Δ modulator.
DETAILED DESCRIPTION OF THE INVENTION
[0052] FIG. 1 shows the device which can be used to align the transfer functions with one another. The inventive device has an operational amplifier OP 1 whose output is connected to the gate of a transistor TR. The noninverting input “+” of the operational amplifier is connected to a reference voltage U REF . The inverting input “−” of the operational amplifier is connected to the source contact of the transistor TR.
[0053] The source contact and the inverting input is also connected to ground via a resistor R I . The resistor R I is the same, in terms of value and geometry (layout, surroundings, orientation on the IC), as the resistor which determines the time constant in an integrating circuit (not shown in this case). The drain contact of the transistor TR is connected to a current mirror S, which is formed by two MOS transistors.
[0054] In this arrangement, the gate contacts of the two MOS transistors are connected to the drain contact of the transistor TR. The source contact of the second MOS transistor in the current mirror S has a connection to a noninverting input “+” on a second operational amplifier OP 2 and to an external resistor R EXT , via which it is connected to ground.
[0055] The resistor R EXT is not integrated in the circuit, but rather is in the form of an external high-precision-resistor. The output of the operational amplifier OP 2 is fed back to the inverting input “−” of the operational amplifier OP 2 . In addition, the output of the operational amplifier OP 2 has two switches S 1 and S 2 . One respective side of the switches S 1 and S 2 is connected to a feedback capacitor C RK . This feedback capacitor stores the charge for the feedback signal.
[0056] The operational amplifier OP 1 and the resistor R I are used to derive a reference current I from the reference voltage U REF . On account of the resistor R I being the same as the resistor which determines the time constant in the integrating circuit, the derived reference current I has a defined relationship with the current which is flowing through the load in the Σ-Δ modulator's integrating circuit (not shown here).
[0057] A current mirror is used to impress this current onto the external resistor R EXT . The voltage drop at the point U RK is thus proportional to 1/R I .
[0058] While the switch S 1 is closed, the feedback capacitor C RK is charged to the voltage U RK via the operational amplifier OP 2 . The charge stored on the feedback capacitor C RK is thus proportional to U RK and is thus likewise proportional to 1/R I .
[0059] If the switch S 1 is open and the switch S 2 is closed, then the feedback capacitor discharges and the stored charge drains. The output A of the device is connected to the input of the integrating circuit in a continuous-time Σ-Δ modulator. The draining charge, which causes a flow of current, is thus added to the input signal for the Σ-Δ modulator.
[0060] The times and the periods in which the switches S 1 and S 2 are switched can be seen in FIG. 4 . The switch S 1 is closed during the period Φ 1 , and is open at all other times. The same applies to the switch S 2 , which is closed during the period Φ 2 . In this case, the period T corresponds to one clock period of the sample signal CLK. In this context, the times Φ 1 and Φ 2 have been set such that their joint duration is shorter than one time period. In addition, the start or end of Φ 1 or Φ 2 is slightly shifted by a value ΔT with respect to the clock alternation for the time period T. In this way, any clock jitter which is present does not affect the discharge time or charging time. In addition, the switches, usually MOS transistors, are provided with sufficient time for the switching operation.
[0061] The time constant τ for charging or discharging the feedback capacitor C RK is chosen such that it is significantly shorter than the time Φ 1 or Φ 2 . The exponential curve thus results in a tiny charging or discharge current at the end of each period Φ 1 and Φ 2 and hence also at the end of each clock period. It may thus be assumed that the capacitor is fully charged or discharged. In practice, the time constant is chosen to be typically shorter than {fraction (1/7)} of the charging time or discharge time Φ 1 and Φ 2 , depending on resolution, which means that the error becomes less than 1 in a thousand.
[0062] An alternative embodiment is shown in FIG. 2 . In this case, identical components bear the same reference symbols, and their operation is not explained again.
[0063] For frequencies<approximately ⅕ of the switching frequency f, a switched capacitor C is equivalent to a resistor R based on R=1/(f*C). Instead of the external resistor R EXT , two parallel-connected capacitors C and C S are used to produce the voltage U RK in this case. C S replaces the resistor, while C is used only for smoothing the voltage produced and for averaging over the charge reversal operations. The capacitor C is connected to the noninverting input “+” of the operational amplifier OP 2 , and the capacitor C S is connected to the same input via a switch S 1 . In addition, the capacitor C S is connected to ground via a switch S 2 . The capacitance of the capacitor C S is much smaller than the capacitance of the capacitor C. However, in this case too, the time constant of the capacitor C S is chosen such that it is charged or discharged fully during the period Φ 1 or Φ 2 .
[0064] During a first switching period, the switches S 1 for charging the capacitors C RK and C S are closed. Hence, a time-dependent current charges the combination of capacitors C and C S up to the voltage U RK which is provided by the capacitance. The voltage U RK is used by the operational amplifier OP 2 in order to charge the capacitor C RK up to this very voltage. During the second period Φ 2 , the switch S 2 is closed, and the capacitor C S is discharged through ground. During the same period, the discharge current from the feedback capacitor C RK is supplied to the input signal for the remaining Σ-Δ modulator (not shown here).
[0065] The voltage at the noninverting input “+” of the operational amplifier OP 2 is also kept at the value U RK by the capacitor C during the period Φ 2 . Since the capacitance of the capacitor C is larger than the capacitance of the capacitor C S , the capacitor C averages out relatively small fluctuations in charge or current. The fluctuations arise, in particular, on account of the influence of the clock jitter. This averaging therefore reduces the influence of the jitter by the square of the number n of averaged cycles.
[0066] Both methods make it possible to change the charge on the feedback capacitor C RK in order to align the transfer function of the feedback system with the transfer function of the load which determines the time constant of the integrating circuit. In this case, the inventive device is part of the feedback device in a circuit which operates on the basis of the Σ-Δ principle. In particular, it may be part of the digital/analog converter DAC, which inverts or does not invert the charge on the feedback capacitor C RK , depending on the data signal, and adds it to the input signal.
[0067] It is a simple matter to modify the circuit in FIG. 1 or FIG. 2 such that it controls the charging or discharge current for a plurality of feedback capacitors. These feedback capacitors are part of a Σ-Δ circuit which operates on the basis of gmC, OTA-C technology or uses differential signals.
[0068] Another embodiment is shown in FIG. 3 . This shows a continuous-time Σ-Δ modulator which has an input V IN and an output A. At the input V IN , the Σ-Δ modulator contains a switch S 3 which can be used to isolate the analog input signal from the Σ-Δ modulator and, in particular, from the integrating part of the modulator. In addition, the input has a connection to a reference signal U REF . This signal can likewise be connected to the input of the Σ-Δ modulator using a switch S 4 .
[0069] The Σ-Δ modulator has an operational amplifier OP 3 which forms an integrating circuit together with a capacitor CL and a resistor R C . To this end, the resistor R C is connected to the noninverting input “+” of the operational amplifier OP 3 and to the signal input V IN of the Σ-Δ modulator via the switch S 3 or to Uref via the switch S 4 . The output of the operational amplifier OP 3 has a feedback loop to the inverting input “−” of the operational amplifier OP 3 via the capacitance CL.
[0070] This arrangement forms a known integrator, with the voltage value at the output of the operational amplifier OP 3 corresponding to the inverted voltage value at the noninverting input “+”. The output voltage from the integrator is compared with a voltage reference value in a comparison circuit CP. The voltage reference value is the ground in this case. The output of the comparison circuit CP is connected to a shift register SR. The output of the shift register SR is routed to a digital/analog converter DAC 2 whose output line is connected to a reference signal U REF . The reference signal U REF is connected to two switches SB 1 and SB 2 .
[0071] The switches SB 1 and SB 2 are part of a switching matrix comprising the switches SB 1 , SB 2 , S 1 and S 2 . The switch S 1 is, as indicated in FIG. 4 , closed during the period Φ 1 and open at all other times. The same applies to the switch S 2 , which is closed during the period Φ 2 . The switches SB 1 and SB 2 can be switched by means of the output signal from the comparison circuit CP. In this case, SB 1 is closed whenever one logic state is present, and SB 2 is closed when the other logic state is present.
[0072] All of the switches S 1 and S 2 in the switching matrix are routed to the feedback capacitor C RK , whose other side is connected via a switch to two further switches S 1 and S 2 . The further switch S 1 can be used to connect the feedback capacitor C RK to ground. The further switch S 2 can be used to connect the feedback capacitor to the noninverting input “+” of the operational amplifier OP 3 during the period Φ 2 .
[0073] In the normal operating situation, the capacitor C RK is charged by the signal U REF in period Φ 1 on the basis of the output signal from the comparison circuit CP. In period Φ 2 , when the switch S 2 is closed, the capacitor discharges via the resistor R C . This results in a change in the voltage at the noninverting input “+” of the operational amplifier OP 3 and hence in a change in the output voltage.
[0074] In the test situation, the switch S 3 at the input V IN is opened and the switch S 4 for the reference signal is closed. In addition, the switches SB 1 and SB 2 are isolated from the output of the comparison circuit CP. A reference voltage U REF now drops across the resistor R C and thus results in a current or in a quantity of charge for a particular period T.
[0075] Ideally, the feedback capacitor C RK is charged with precisely the opposite quantity of charge flowing through the resistor R C during the period T. The two opposite charges compensate for one another in the ideal situation, and the flow of current through R C and also the voltage at the noninverting input of the operational amplifier OP 3 disappear.
[0076] If the charges flowing through R C and via C RK now do not match during the period T, then a current or charge difference becomes established at the input of the operational amplifier OP 3 . This produces a voltage at the output of the operational amplifier which is a measure of the error in the transfer functions. The arithmetic sign of the voltage indicates which of the two currents or of the two quantities of charge is the greater.
[0077] Since this error is a systematic discrepancy, it is accumulated by a fresh measurement. The voltage across the capacitor CL becomes correspondingly higher. After 1000 clock cycles, for example, the switches SB 1 and SB 2 are connected to the output of the comparison circuit CP again. At the same time, a zero signal is applied to the input of the Σ-Δ modulator via the switch S 4 .
[0078] The output of the comparison circuit CP now delivers a logic state which is used to produce a corresponding feedback signal. The feedback signal is opposite to that at the input of the comparison circuit CP.
[0079] This is achieved by charging the feedback capacitor C RK with a defined and quantized quantity of charge again which is obtained from the reference voltage U REF and the capacitance of the feedback capacitor. This quantity of charge is supplied to the input of the operational amplifier OP 3 in the time period Φ 2 .
[0080] This reduces the charge stored on the capacitor CL in the operational amplifier OP 3 as a result of the error, and the voltage at the output falls by the corresponding magnitude. This operation is repeated until the charge difference on the capacitor CL has disappeared. At this point in time, the logic state at the output of the comparison circuit changes.
[0081] The number of individual states for the comparison circuit CP before this change is stored in the shift register SR. This is a measure of the magnitude of the error. The arithmetic sign of the output signal from the comparison circuit up to the first change indicates the arithmetic sign of the discrepancy. This method provides a way of accurately determining the mismatch between feedback capacitor C RK and integration resistor R C up to half a capacitor charge. The minimum error is thus just half an LSB.
[0082] Once the mismatch between the resistor R C and the capacitor C RK has been determined in this manner, an adjustment can be made. This is done by counting the number of identical logic states in the shift register SR. A DAC converter DAC 2 is then used to add an appropriate signal to the reference voltage U REF so as to align the transfer function of the capacitor C RK with the transfer function of the resistor R C .
[0083] If, by way of example, an accumulated error voltage across CL over 1000 clock cycles results in a mismatch for 250 capacitor charges in the feedback capacitor, then the digital/analog converter DAC 2 needs to be used to increase or reduce the reference voltage U REF by one quarter, depending on the arithmetic sign of the output signal from the comparison circuit CP.
[0084] Another means of alignment may be for the resistance R C to be altered by adding or omitting individual component resistances. These may be connected in parallel or in series. This alters the time constant of the integrating circuit.
[0085] Yet another option is to change the capacitance of the feedback capacitor by adding or omitting individual component capacitances. It is naturally also possible to find combinations of these options.
[0086] This method provides a simple way of achieving alignment, which firstly reduces the quantization noise and increases the stability of the converter. Since it is not possible to evaluate an input signal during measurement of the difference between feedback capacitor and the load which determines the time constant, the measurement needs to be taken during a powerup sequence and/or during burst pauses. Hence, periodic performance and readjustment are also possible, however, for example in order to be able to react to temperature fluctuations.
[0087] A core concept of the invention is thus circuits and a method which aligns the transfer function of a feedback capacitor in a feedback device with the transfer function of the load which determines the time constant. Such a circuit is preferably used in continuous-time Σ-Δ modulators. In this case, the exemplary embodiments discussed here can be combined with one another in any way, as can the measurement method described.
[0088] It is not limited thereto, however, but rather may also be applied to any conceivable architecture for ρ-Δ converters, that is to say particularly to any low pass or band pass converter, to real and complex converters, single-loop or cascading converters. Next to this is use in single-ended or in differential embodiments of the stated converters. The inventive circuit can thus easily be implemented in a fifth order Σ-Δ modulator in the differential embodiment in FIG. 6 .
List of Reference Symbols
[0089] (S): Current mirror
[0090] (U REF ): Reference voltage
[0091] (U RK ): Charging voltage
[0092] (OP 1 , OP 2 ): Operational amplifier
[0093] (OP 3 ): Operational amplifier
[0094] (TR): Transistor
[0095] (R I ): Resistor
[0096] (R EXT ) External resistor
[0097] (S 1 , S 2 ): Switch
[0098] (S 3 , S 4 ): Switch
[0099] (SB 1 , SB 2 ): Switch
[0100] (C RK ): Feedback capacitor
[0101] (C, C S ): Capacitors
[0102] (Φ 1 , Φ 2 ): Period
[0103] (T): Period of a clock cycle
[0104] (Δt): Time difference
[0105] (A): Output
[0106] (V IN ): Input of the Σ-Δ modulator
[0107] (E): Input of the comparison circuit
[0108] (CP): Comparison circuit
[0109] (CLK, CLK 2 ): Clock input with clock signal
[0110] (SR): Shift register
[0111] (DAC, DAC 2 ): Digital/analog converter
[0112] (R C ): Resistor
[0113] (CL): Charge capacitor
[0114] (I): Integrating circuit
[0115] (DF): Decimator
[0116] (Int 1 . . . INT 5 ): Integration elements
[0117] (R in,1, R in, 2 ): Low pass filter
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The invention proposes includes a circuit that operates continuously in the time domain on the basis of the sigma-delta principle. The circuit includes at least one integrating circuit that is characterized by a first transfer function, and has a comparison circuit having a clock signal applied thereto that compares an output signal coming from the at least one integrating circuit with a reference signal and delivers a binary output signal. The circuit further includes an apparatus for signal feedback that is connected to the output of the comparison circuit and to the input of the at least one integrating circuit, and is characterized by a second transfer function. Further, an alignment device is provided that aligns the second transfer function of the apparatus for signal feedback with the first transfer function of the integrating circuit.
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This is a continuation of copending application U.S. Ser. No. 07/896,207, filed Jun. 10, 1992. U.S. Ser. No. 07/896,207 was a continuation-in-part application of U.S. Ser. No. 07/781,758 filed Oct. 23, 1991, both now abandoned.
FIELD OF INVENTION
This invention relates to an improvement in unlubricated wear of bearing surfaces for such materials as aluminum and zinc.
BACKGROUND OF THE INVENTION
The use of nickel coated graphite particles was taught by Badia et al in U.S. Pat. Nos. 3,753,694 and 3,885,959. The nickel coated graphite particles provided improved machinability and wear resistance to aluminum castings. However, the process of Badia et al has disadvantages resulting from nickel coated graphite being dispersed throughout the aluminum casting. The graphite particles lower strength and related properties throughout the aluminum-base casting. Optimally, graphite particles are only placed at surfaces where increased wear and machinability properties arc desired to minimize negative effects arising from graphite.
An additional technique for improving wear resistance of aluminum alloys is disclosed in U.S. Pat. No. 4,759,995 of Skibo et al. Skibo et al teach dispersion of SiC throughout aluminum castings. The SiC particles do not degrade strength properties as much as graphite. However, the process of Skibo et al also has disadvantages. The extremely hard surface of a SiC composite does not hold lubricant well or provide intrinsic lubrication properties. Thus, as a result of SiC composites poor ability to hold lubricant. SiC particles may actually increase unlubricated wear rate.
Another related technology for improving wear resistance relates to pressure injection molding or squeeze casting a preform constructed of a combination of carbon fibers and alumina fibers. The pressure injection method is disclosed by Honda in U.S. Pat. Nos. 4,633,931 and 4,817,578. According to the method disclosed in Honda, a combination of carbon and alumina fibers are dispensed and formed into a preform and placed into the desired area of the casting, i.e. on the inside of a cylinder wall of an internal combustion engine. The desired features of Honda's process are that it provides both a hard phase (Al 2 O 3 ) for improved wear properties and carbon fiber for improved unlubricated wear properties. Furthermore, any degradation in strength is isolated to regions of the casting containing the fiber preform. However, the process disclosed by Honda requires a pressure of about 20 to 250 MPa applied to molten aluminum metal to infiltrate the preform of alumina and carbon fiber. This high pressure requirement causes the price of pressure injecting a preform to be very expensive.
It is the object of this invention to provide a low pressure method for producing a localized mixture of hard wear resistant particles and a lubricating carbon phase at the wear surface of a light metal casting.
SUMMARY OF THE INVENTION
The invention produces a light metal alloy composite having nickel coated graphite or carbon with a nickel-containing intermetallic phase within a portion of a casting. A mold is provided to cast a light metal into a predetermined shape. A nickel coated carbon structure is placed into a portion of the mold. The light metal is cast into the mold around the carbon structure to wet an interface between the light metal and the nickel coated carbon structure. A nickel-containing intermetallic phase is formed in the light metal proximate the nickel coated carbon to provide increased wear resistance. The light metal is then solidified to form the metal matrix composite.
DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic drawing of a pressure assisted infiltration unit for fabricating tensile and impact energy specimens.
FIG. 2a is a cross-sectional photomicrograph of a carbon/aluminum composite reinforced with uncoated carbon fibers at 100X magnification.
FIG. 2b is a cross-sectional photomicrograph of a carbon/aluminum composite reinforced with nickel coated carbon fibers at 200X magnification.
FIG. 3a is a photomicrograph of composite formed with nickel coated carbon paper at 200X magnification.
FIG. 3b is a photomicrograph of composite formed with nickel coated carbon paper at 500X magnification.
FIG. 4a is a photomicrograph of hypoeutectic Al--Si alloy A356 at 200X magnification.
FIG. 4b is a photomicrograph of hypoeutectic Al--Si alloy A356 modified with nickel coated graphite at 200X.
FIG. 5 is a graph of wear rate versus load for alloy A356, alloy A356 strengthened with SiC and alloy A356 strengthened with nickel-coated carbon paper.
FIG. 6 is a photomicrograph of hypereutectic alloy Al-12 Si with nickel coated carbon fibers at a 200X magnification.
DESCRIPTION OF PREFERRED EMBODIMENT
This invention provides for the in situ formation of a hard phase in a softer injected metal phase at the wear surface of said cast part while at the same time providing the carbon lubricating phase. This invention provides an article and a low pressure method of fabrication of a cast part which contains a mixture of hard particles and carbon at the wear surface. Carbon is not distributed throughout the entire body of the casting.
The method of fabrication involves nickel coating on carbon structures such as carbon or graphite fibers, felt or paper, forming same into a preform shape, placing the preform in the desired place in the mold, then casting the part in a light metal. For purposes of this specification, carbon phase defines carbon, graphite and a mixture of carbon and graphite. A light metal is defined for purposes of this specification as aluminum, an alloy of aluminum, zinc, or an alloy of zinc. Specific examples of most advantageous aluminum-silicon alloys to be used with nickel coated carbon are the 300 series alloys provided in ASM Metals Handbook, Volume 2. Tenth Edition, pages 125-127 and 171. Most advantageously, aluminum-silicon alloys used for the method of the invention contain about 5 to 17 wt. % silicon for improved hardness. Examples of zinc alloys expected to operate with nickel coated carbon of the invention arc zinc die casting alloys provided on pages 528-29 of the above-referenced Metals Handbook. During the casting or injection molding, the nickel coating provides a readily wettable surface to facilitate a modest or low pressure, i.e. about 0.7 Mpa to infiltrate the preform. The nickel dissolves off the fibrous or particulate preform as the molten Al or Zn or alloy thereof infiltrates the preform. The nickel metal reacts with the Al or Zn to form intermetallic compounds of Al 3 Ni. AlNi, Ni 2 Al 3 , or Ni 3 Zn 22 in situ inside of the fibrous preform. The nickel coating provides oxidation resistance and evolves heat during the phase transformation to nickel-containing intermetallics. The resultant preform ends up as a fibrous or particulate carbon phase, a hard nickel aluminide phase (or Ni 3 Zn 22 ) in a matrix of the casting alloy. Advantageously, nickel-containing intermetallics are formed within 1 millimeter of the carbon structure. Most advantageously, the nickel-containing intermetallics are formed within 0.1 millimeter of the carbon structure.
The above composite, or method of manufacture of same, is particularly useful for production of engine liners and engine liner inserts. For production of engine liners, preforms are placed into a mold and cast into the desired shape. For production of, engine liner inserts, preforms are cast into cylindrical molds to form hollow composite cylinders that are subsequently cast into an engine block. A low infiltration pressure with improved wetting is used to provide a carbon phase for lubrication and a hard phase for improved wear resistance. The carbon phase and hard phase are only supplied where desired. For example, with piston liners and piston liner inserts, carbon phase and intermetallic phase is advantageously placed on the piston bearing surface.
Pressure caster 10 of FIG. 1 was used to evaluate various composites and methods for forming the composites. Referring to FIG. 1, pressure caster 10 was heated with induction coil 12 and maintained in an inert atmosphere 14. Most advantageously, an inert gas such as argon flows through gas inlet 16 and out gas outlet 18 to maintain a protective atmosphere for preventing excessive oxidation of liquid metals within housing 20. Housing 20 is preferably constructed with quartz tube 22 and end caps 24 and 26. Within housing 20, graphite mold 28 had a bottom seat 30, die cap 32 and cooling block 34 to provide a space for forming composites. Thermocouple 36 measured the temperature of graphite mold 28. Push rod 38 was used to drive plunger 40 which pushed liquid light metal alloy 42 into graphite die 44. Light metal was pushed between fibers 46 within graphite die 44 to form a test sample. The test sample was allowed to solidify as a metal matrix composite.
EXAMPLE 1(A)
A 12,000 filament tow of Hercules AS4 carbon fiber was placed in a 5 mm hole in a graphite die 44. A 2.5 cm diameter cylinder of pure aluminum 2.5 cm high was placed on top of the graphite die 44 and was enclosed in graphite mold 28 of FIG. 1. The apparatus of FIG. 1 was purged with argon, then heated by induction coils to 705° C. After 5 minutes, the aluminum was molten and a pressure of 4.5 MPa was applied to the plunger. A cross-section of the casting is shown in FIG. 2a.
EXAMPLE 1(B)
Example 1(A) was repeated except that the AS4 fiber was coated with 20 wt. % Ni prior to placing in the die. A cross-section of the casting is shown in FIG. 2b. From FIG. 2b it is apparent that the nickel coated carbon fibers were properly wetted by the molten aluminum while FIG. 2a shows that the uncoated carbon fiber was not wetted and tended to cluster together when the molten aluminum was infiltrated into the preform. Examples 1(A) and 1(B) illustrate the usefulness of the nickel coating to promote wetting of the carbon fiber by aluminum.
EXAMPLE 2
A series of composite cylinders were made by low pressure liquid infiltration of nickel coated carbon preform. The nickel coated carbon paper of felt used to make the preforms is described in a paper by Bell and Hansen presented at the Sampe Technical Conference, Lake Kianeska, N.Y., October 1991.
A carbon paper weighing 34 g/m 2 and containing approximately 97 percent voids was coated with 33 wt. % Ni. The paper was 0.3 mm thick and was cut and rolled around a solid graphite cylinder about 15 mm in diameter so that it formed a cylindrical preform with a wall thickness of 3 to 5 mm and a length of 75 mm. The solid graphite rod with the cylindrical preform on it, was placed inside a 23 mm I.D. stainless steel tube.
The stainless tube holding the preform was then placed in a Pcast 875L Pressure Infiltration Casting Machine and held at 400° C. The pure aluminum in the bottom of the apparatus was then heated to 700° C., then forced up into the preform by argon at 0.7 MPa (100 psi) pressure. The infiltration time was only a few seconds. When the thermocouples had indicated that the aluminum was solid, the composite was removed from the apparatus.
Optical micrographs of a cross-section of the composite are shown in FIGS. 3a and 3b. It is illustrated that most carbon fibers (black) are oriented parallel to the plane of the carbon paper and that they are evenly distributed throughout the aluminum matrix. Higher magnification (FIG. 3b) shows varying amounts of Ni x Al y intermetallics adjacent to fiber surfaces.
These precipitates have been identified by semi-quantitative X-ray analysis as predominantly NiAl 3 as expected from the Ni--Al binary phase diagram.
The hardness of the pure aluminum was 11.8±0.6 on the HR-15T scale while the hardness of the composite inside the area of the preform was 45±3 on the same scale.
This example illustrates the principle features of the invention; namely, the nickel coating provides two essential properties; it provides for low pressure wetting of the carbon fiber by the infiltrating metal and modifies the alloy inside the volume of the carbon fiber preform so as to produce hard intermetallic compounds.
EXAMPLE 3
The process is not confined to the use of pure metals for infiltration.
A 97% porous nickel coated carbon felt (62 wt. % Ni) 2.3 mm thick was packed into 13 mm O.D. quartz tubes and infiltrated with a hypoeutectic Al--Si casting alloy A356 (7% Si; 0.3% Mg). The apparatus in Example 2 was used with a lower preform and melt temperature of 350° C. and 650° C. respectively.
Infiltration pressures were limited to between 1.05 MPa and 2.8 MPa (400 psi) (Ar). In general, the samples were less porous than the pure aluminum counterpart in Example 1(B) owing to slightly higher infiltration pressures and the increased fluidity of the Al--Si alloy. The normal cast structure of the A356 alloy is shown in FIG. 4a in an area remote from the preform.
FIG. 4b shows the distortion of the Al--Si eutectic inside the preform by the presence of the Ni from the graphite preform. The NiAl 3 phase is seen to be coarser than in the pure aluminum matrix of Example 2.
The hardness of the casting was essentially the same on the HR-15T scale or 70 for both the normal A356 alloy and the modified alloy inside the volume of the reform.
Alloys A356, A356-20 vol. % SiC (F3A.20S as produced by ALCAN) and A356 nickel-coated carbon paper were tested in accordance with "Standard Practice for Ranking Resistance of Materials to Sliding Wear Using Block-on-Ring Wear Test," G77, Annual Book of ASTM Standards, ASTM, Philadelphia, Pa., 1984, pp. 446-462. Alloys A356 and A356-20 vol. % SiC were tempered with a T-6 condition to improve matrix strength. FIG. 5 compares the wear resistance of unreinforced A356 alloy with A356 matrices reinforced with SiC particulate or nickel-coated carbon paper. Both reinforced alloys exhibit superior wear resistance to unreinforced A356 over a load range representative of that in an internal combustion engine. The A356 nickel-coated carbon paper composite compares favorably to the SiC reinforced alloy and is noticeably more wear resistant at high load (>180N). This is thought to be due not only to the lubricating qualities of graphite, but also the increased abrasion resistance of the Al 3 Ni intermetallic phase. Most advantageously, alloys of the invention are characterized by a wear rate of less than 10 micrograms/m at a load of 200N for the Block-on-Ring Wear Test.
This example shows that the process and finished composite part can be produced by using an alloy in addition to pure metals. If an alloy like A356 is chosen for its low casting temperature and/or low coefficient of solid thermal expansion, the nickel coating also provides ease of wetting of the carbon preform and still modifies the microstructure of the alloy inside of the preform while maintaining or improving its hardness. The properties of the casting remote from the preform remain unchanged.
EXAMPLE 4
A hypereutectic Al-12Si alloy/nickel-coated graphite composite cylinder was squeeze-cast at a moderate pressure of 8.4 MPa (1200 psi). The preform was prepared by a method similar to Example 2 to give an outside diameter of 32 mm and a wall thickness of 3 min. The nickel coated carbon preform was made from the same material present in Example 3. The melt temperature was 730° C.
The microstructure depicted in FIG. 6 contained a large chunky intermetallic phase in addition to the acicular NiAl 3 precipitates also present in Example 3. These aluminides correspond to NiAl stoichiometry and are randomly dispersed in the distorted Al--Si matrix.
The normal acicular silicon phase has been suppressed and is mostly too fine to be observed in FIG. 6.
Again, since the silicon phase in the hypereutectic Al--Si alloys is hard, the hardness of the casting inside the area of the preform of 75 cm on the HR-15T scale was the same as the normal part of the casting. However, the microstructure of the casting inside the volume of the preform has been completely altered.
It has been discovered that it is most advantageous to preheat nickel coated carbon structures in an inert atmosphere when preheating nickel coated carbon structures at temperatures above about 300° C. Nickel oxidizes in air at temperatures above about 300° C. Nickel oxides reduce wetting and react with aluminum and aluminum-base alloys to form aluminum oxide scale which is believed to impede the formation of beneficial nickel-containing intermetallics.
The Examples have shown that the composite and method of the invention provide several advantages. First, the nickel coating improves wetting and reduces pressure required to infiltrate a carbon phase composite structure. Most advantageously, a pressure of only 35 KPa to 10 MPa is used which reduces equipment costs. Second, a graphite phase is provided for improved lubrication. Most advantageously, the carbon phase originates from either pitch or polyacrylonitrile precursor. Third, the invention provides a hard nickel-containing intermetallic phase such as Al 3 Ni or Ni 3 Zn 22 for improved hardness adjacent to the nickel coated graphite. Most advantageously, graphite is coated with about 15 to 60 wt. % nickel or about 0.065 to 0.85 micrometers of nickel to promote formation of nickel-containing intermetallic phase. Optionally, alumina or nickel coated alumina may be added to the nickel coated carbon phase to further improve wear resistance. Fourth, the carbon phase and nickel phase are only placed where desired within a composite. The composite free region of the casting is free from unnecessary detrimental strength losses arising from carbon particulate. Fifth, the reaction between the nickel coating and the light metal alloy to form a nickel-containing intermetallic phase liberates heat. The preheat temperature required for the die and preform would therefore be reduced. Finally, the nickel coating protects the carbon fibers from oxidation. Uncoated fibers will burn in air at high temperatures greater than 350° C. resulting in the loss of carbon as gaseous carbon oxides and a corresponding loss in strength due to pitting of the fiber surface.
While in accordance with the provisions of the statute, there is illustrated and described herein specific embodiments of the invention, those skilled in the art will understand that changes may be made in the form of the invention covered by the claims and that certain features of the invention may sometimes be used to advantage without a corresponding use of the other features.
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The invention produces a light metal alloy composite having a nickel coated graphite or carbon with a nickel-containing intermetallic phase within a portion of a casting. A mold is provided to cast a light metal into a predetermined shape. A nickel coated carbon phase structure is placed into a portion of the mold. The light metal is cast into the mold around the carbon structure to wet an interface between the light metal and the nickel coated carbon structure. A nickel-containing intermetallic phase is formed in the light metal proximate the nickel coated carbon to provide increased wear resistance. The light metal is then solidified to form the metal matrix composite.
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FIELD OF THE INVENTION
This invention relates to a method of stabilizing xanthan gum, produced in a liquid nutrient medium by the action of a microorganism belonging to the genus Xanthomonas, in an aqueous solution.
BACKGROUND OF THE INVENTION
Xanthan gum is used widely in a number of industrial fields, such as oil-well drilling, the ceramic industry, the paint industry, and the like. However, its performance characteristics frequently deteriorate even during storage at room temperature; such tendency becomes significant at higher temperatures and, in extremely cases, the use thereof for the intended purpose becomes impossible.
For example, in the case of petroleum recovery from an underground oil stratum by introducing under pressure an aqueous solution of xanthan gum, the oil stratum temperature generally reaches about 40° to 100° C. and the aqueous xanthan gum solution injected stays in the underground oil stratum from the injection well to the production well for a long period of time, for example, several months to scores of months. Therefore, guarantees of the quality of xanthan gum during such periods have been demanded.
Xanthan gum is also widely used as a modifier for the mud-laden fluid for mud drilling in searching for petroleum. However, with the recent increase in the depth of drilling, the stratum temperature reaches 90° C. or even higher so that xanthan gum is decomposed and loses its function as a modifier for the mud-laden fluid, possibly leading to serious difficulties in drilling operations. For xanthan gum to fully achieve the intended purpose of its use, it is necessary to minimize the change of quality of xanthan gum in the above temperature range over the course of time.
SUMMARY OF THE INVENTION
The present inventors have conducted extensive and intensive studies on the stabilization of xanthan gum in aqueous solution and on additives for such stabilization and, as a result, found that decomposition of the xanthan gum can be substantially inhibited by incorporating a thiol derivative of a heterocyclic compound. This finding has now led to the present invention.
Thus, the present invention relates to a method of stabilizing xanthan gum in an aqueous solution comprising incorporating, in an aqueous solution of xanthan gum, at least one member selected from the group consisting of the thiol derivatives of heterocyclic compounds hereinafter described.
DETAILED DESCRIPTION OF THE INVENTION
The thiol derivatives of heterocyclic compounds which can be used for stabilization of xanthan gum are 2-mercaptobenzothiazole and its derivatives represented by the formula (I); 2-thioimidazolidone represented by the formula (II); 2-mercaptothiazoline represented by the formula (III); benzoxazole-2-thiol represented by the formula (IV); N-pyridineoxide-2-thiol represented by the formula (V); 1,3,4-thiadiazole-2,5-dithiol represented by the formula (VI); and 4-ketothiazolidine-2-thiol represented by the formula (VII): ##STR1## wherein R 1 , R 2 , R 3 and R 4 each represents a hydrogen atom, a methyl group or an ethyl group; and X represents a hydrogen atom, an alkali metal or ammonium.
It is known that thiourea, 2-mercaptobenzothiazole and derivatives thereof are effective to stabilize aqueous solutions of acrylamide polymers as described, e.g., in U.S. Pat. Nos. 3,235,523 and Japanese Patent Publication Nos. 47414/83 and 48583/83. On the other hand, it is also known that thiourea is substantially ineffective in the stabilization of aqueous xanthan gum solutions. Thus, it is well known in the art that a certain stabilizing agent which is effective in stabilizing some substances is not always effective in stabilizing other substances. This is presumably because the mechanisms of stabilization differ in various ways depending on the combination of the stabilizing agent and the substance to be stabilized.
Under these circumstances, the present invention has been completed based on the finding that the particular combination of the above-described compounds and xanthan gum is very effective in the stabilization of aqueous solutions of xanthan gum.
The terminology "xanthan gum" as used herein means a substance produced in a liquid nutrient medium by the action of a microorganism belonging to the genus Xanthomonas. Such substance is commercially available, for example, from Kelco, USA under the trade names "Kelzan" and "Xanflood" and from Pfizer, USA under the trade names "Flocon" and "Pfizer Xanthan Biopolymer". The aqueous xanthan gum solution to be stabilized in accordance with the present invention preferably has a concentration of from about 0.0001 to 10% by weight, and it is particularly preferred that the invention be applied to aqueous xanthan gum solutions having concentrations ranging from about 0.0001 to 5% by weight.
The above-described stabilizing agents may be used either alone or in combinations of two or more thereof. Further, they may also be used in combination with other known stabilizing agents. The stabilizing agents in accordance with the present invention are used in an amount of from 0.05 to 20 parts by weight per 100 parts by weight of xanthan gum. Amounts less than 0.05 part by weight produce only poor stabilizing effects, whereas addition in amounts exceeding 20 parts by weight produces little difference in the stabilzing effect as compared with the level obtained by addition of 20 parts by weight, and hence is unfavorable from an economical viewpoint.
In carrying out the present invention, the stabilizing agent can be incorporated in the aqueous xanthan gum solutions, for example, (1) by mixing the stabilizing agent in powder form with xanthan gum in powder form using a mixer or a blender, (2) by admixing the stabilizing agent in the form of powder or aqueous solution with a xanthan gum-containing fermentation broth, or (3) by adding the stabilizing agent in the form of powder or aqueous solution to an aqueous solution of xanthan gum with stirring.
With aqueous xanthan gum solutions stabilized in accordance with the present invention, the stabilizing effect is manifested not only at room temperature but also at a temperature as high as 90° C. The stabilizing effect at high temperatures is particularly useful.
The kind of water to be used in preparing aqueous xanthan gum solutions may vary depending on the intended use of said solutions but is not critical. Thus, the water can appropriately be selected from among seawater, ground water, river water, city water, industrial water, etc.
The following examples are further illustrative of the effect of this invention.
EXAMPLE 1
In 1,000 g of deionized water was dissolved 5.0 g of Kelzan (trade name of xanthan gum produced by Kelco, USA) to prepare a 0.5% aqueous xanthan gum solution. The solution had a viscosity of 2,410 cp (Brookfield viscometer No. 2 rotor, 6 rpm, 25° C.).
The above xanthan gum was dissolved in a 3% aqueous sodium chloride solution to make a 0.12% aqueous xanthan gum solution. After the solution was adjusted to a pH of 9, its viscosity (initial viscosity, Ao) was measured. Then, a specified amount (see Table 1) of a sodium salt of 2-mercaptobenzothiazole (MBT-Na) was added thereto, and the resulting solution was heated in a glass ampule at 120° C. for 3 or 20 hours, followed by measuring the viscosity (At). The change in quality of the solution with time was evaluated by obtaining a percent viscosity loss (At/Ao×100). The results thus obtained are shown in Table 1 below.
TABLE 1______________________________________Amount of Viscosity Loss (%)MBT-Na Added After After(%)* 3 Hours 20 Hours______________________________________0 25.6 88.20.5 8.9 72.32.0 3.9 34.65.0 3.0 21.97.5 2.7 18.615.0 2.0 11.7______________________________________ Note: *% by weight based on the polymer (hereinafter the same)
EXAMPLE 2
The procedure of Example 1 was repeated except that a sodium salt of 2-mercaptobenzothiazole having its benzene ring substituted with a methyl group (MMBT-Na) was used in place of MBT-Na used in Example 1. The results obtained are shown in Table 2 below.
TABLE 2______________________________________Amount of Viscosity Loss (%)MMBT-Na Added After After(%) 3 Hours 20 Hours______________________________________0 26.3 88.00.5 9.6 73.52.0 4.4 33.95.0 3.6 22.07.5 2.9 17.415.0 2.4 10.9______________________________________
EXAMPLE 3
A 0.1% aqueous solution of xanthan gum was prepared by dissolving the same xanthan gum species as used in Example 1 in tap water, adjusted to a pH of 9.0 and, following addition of MBT-Na as in Example 1, subjected to heat treatment at 90° C. for 3 or 20 hours. Thereafter, the percent viscosity loss was obtained in the same manner as in Example 1. The results obtained are shown in Table 3 below.
TABLE 3______________________________________Amount of Viscosity Loss (%)MBT-Na Added After After(%) 3 Hours 20 Hours______________________________________0 46.7 89.60.5 13.9 75.62.0 8.0 59.05.0 4.5 38.37.5 3.6 20.615.0 2.9 15.7______________________________________
EXAMPLE 4
The procedure of Example 1 was repeated except that 2-mercaptobenzothiazole (MBT) was used in place of MBT-Na. The results obtained are shown in Table 4.
TABLE 4______________________________________Amount of Viscosity Loss (%)MBT Added After After(%) 3 Hours 20 Hours______________________________________0 26.0 89.20.5 10.0 73.12.0 3.8 34.87.5 2.9 23.0______________________________________
EXAMPLE 5
The procedure of Example 1 was repeated except for changing the concentration of the xanthan gum aqueous solution to 0.1%, using 2-thioimidazolidone in place of MBT-Na and changing the heating temperature to 110° C. The results obtained are shown in Table 5 below.
TABLE 5______________________________________Amount of 2-Thioimida- Viscosity Loss (%)zolidone Added After After(%) 3 Hours 20 Hours______________________________________0 19.3 81.50.5 6.6 69.02.0 2.1 25.35.0 1.8 14.67.5 1.0 11.215.0 0.9 7.0______________________________________
EXAMPLE 6
The procedure of Example 1 was repeated except for using a 3% sodium chloride-0.3% calcium chloride aqueous solution in place of the 3% sodium chloride aqueous solution, changing the concentration of the xanthan gum aqueous solution to 0.1% and using 2-mercaptothiazoline in place of MBT-Na. The results thus obtained are shown in Table 6 below.
TABLE 6______________________________________Amount of 2-Mercapto- Viscosity Loss (%)thiazoline Added After After(%) 3 Hours 20 Hours______________________________________0 25.4 91.60.5 8.4 80.02.0 3.0 36.35.0 2.1 21.37.5 1.8 16.615.0 1.3 13.3______________________________________
EXAMPLE 7
The procedure of Example 1 was repeated except for using a 3% sodium chloride-0.3% calcium chloride aqueous solution in place of the 3% sodium chloride aqueous solution, changing the concentration of the xanthan gum aqueous solution to 0.08%, using benzoxazole-2-thiol in place of MBT-Na and changing the heating temperature to 110° C. The results obtained are shown in Table 7.
TABLE 7______________________________________Amount of Benzoxazole- Viscosity Loss (%)2-Thiol Added After After(%) 3 Hours 20 Hours______________________________________0 27.6 92.00.5 7.8 68.32.0 3.0 26.15.0 1.9 14.17.5 1.0 12.215.0 1.0 9.4______________________________________
EXAMPLE 8
The procedure of Example 1 was repeated except for using tap water in place of the 3% sodium chloride aqueous solution, using N-pyridineoxide-2-thiol in place of MBT-Na and changing the heating temperature to 100° C. The results thus obtained are shown in Table 8 below.
TABLE 8______________________________________Amount of N--Pyridine- Viscosity Loss (%)oxide-2-Thiol Added After After(%) 3 Hours 20 Hours______________________________________0 44.4 91.30.5 13.6 74.62.0 8.8 59.15.0 6.1 33.67.5 5.8 20.915.0 4.5 14.5______________________________________
EXAMPLE 9
The procedure of Example 1 was repeated except for using 1,3,4-thiadiazole-2,5-dithiol in place of MBT-Na and changing the heating temperature to 115° C. The results obtained are shown in Table 9.
TABLE 9______________________________________Amount of 1,3,4-Thiadiazole-,2,5- Viscosity Loss (%)Dithiol Added After After(%) 3 Hours 20 Hours______________________________________0 21.6 88.30.5 13.4 75.52.0 9.3 31.45.0 7.4 18.17.5 5.0 15.115.0 4.1 13.9______________________________________
EXAMPLE 10
The procedure of Example 1 was repeated excpet for using tap water in place of the 3% sodium chloride aqueous solution, changing the concentration of the xanthan gum aqueous solution to 0.8%, using 4-ketothiazolidine-2-thiol in place of MBT-Na and changing the heating temperature to 105° C. The results obtained are shown in Table 10.
TABLE 10______________________________________Amount of 4-Ketothia- Viscosity Loss (%)zolidine-2-Thiol Added After After(%) 3 Hours 20 Hours______________________________________0 41.6 90.50.5 21.1 72.12.0 10.6 54.15.0 7.3 30.67.5 6.0 19.815.0 5.5 15.7______________________________________
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
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A method of stabilizing an aqueous solution of xanthan gum is disclosed, comprising incorporating at least one stabilizing agent selected from thiol derivatives of heterocyclic compounds in an aqueous solution of xanthan gum.
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CROSS REFERENCES
[0001] None.
GOVERNMENT RIGHTS
[0002] None.
BACKGROUND OF THE DISCLOSURE
[0003] In the field wound care, it is a known strategy to separate whole blood into various sub-components and to apply stimulated sub-components to damaged tissue in an effort to accelerate, augment, or effectuate the tissue repair, closure, and healing process. It is generally understood that the whole blood is separated by centrifugation, sequestration, filtration, or other mechanical process such that at least three dominant components are isolated based on molecular weight or size. At least three components are understood to result from such traditional separation, including but not limited to red blood cells, platelet-poor plasma, and platelet-rich plasma. The platelet-rich plasma may comprise platelets, white blood cells, fibrinogen, plasma, stem cells and plasma proteins.
[0004] Generally, in connection with creating a tissue sealant and/or filler for use in acute or chronic wound healing and damaged tissue repair, the prior art attempts to activate the platelet rich plasma or the platelet-poor plasma portions by saturating either the platelet rich or platelet poor plasma portion with significant amounts of bovine-derived thrombin, collagen, serotonin, or other agonist. Following such activation, it is known that a variety of cellular pathways are triggered in such a way as to inevitably increase the viscosity of the plasma portion(s). For example, it is understood that, as part of these pathways and following the introduction of an agonist, fibrinogen present in the plasma portion will transform into fibrin. There is substantial evidence in the prior art that bovine-derived thrombin is applied in copious amounts in order to activate the respective plasma portions and/or platelet concentrates. For example, U.S. Pat. No. 6,524,568 indicates a range between 100 U and 10,000 U exogenous thrombin as mixed with an 8 mL platelet concentrate volume, and the patent claims a preferred amount of 1000 U thrombin per 8 ml of platelet concentrate.
[0005] The use of bovine or non-human-derived products is a widely used phenomenon. All this may be in accepted practice today, yet the inventor understands that it is best to significantly depart from the use of bovine-derived products in connection with the unsafe circumstances surrounding bovine spongiform encephalitis, known as BSE. As such, because it is very difficult at this point in time to even test for infection of BSE, the inventor invested substantial time and effort into formulating a method and procedure whereby no exogenously-applied thrombin or similar agonist is utilized. Obviously, because thrombin is endogenous to mammals, the inventor makes clear that this patent does not seek to neutralize or vitiate endogenous thrombin.
[0006] Thus, while exogenous thrombin is the current protocol in activating either platelet-rich plasma or platelet-poor plasma, the disclosure herein serves to satisfy in part, the goal of eliminating the reliance on super-saturation levels of exogenously applied thrombin, be the source of such thrombin derived from bovine sources or the product of concentration of the patient's own thrombin. It is believed that the reduction in exogenously-applied thrombin will translate into elevated confidence in certain medical procedures, easier compliance with federal regulations governing exogenously applied chemicals in the health care industry, and decreased cost in obviating the need for high-cost purification of bovine-derived thrombin or similar agonist.
SUMMARY
[0007] This disclosure relates to the stimulation of blood plasma portions by creating a steady rate turgid gas and plasma portion interface. By creating a turgid gas/liquid interface, under controlled conditions, this disclosure thus seeks to activate the biological components associated with tissue repair and wound care in a manner that reduces exogenous chemical contact or treatments. In application, the inventor contemplates stimulating platelet rich plasma by careful percolation or injection of oxygen gas through an amount of platelet-rich plasma, although the same principles apply in either platelet-poor plasma or with whole blood as well.
[0008] In the first preferred embodiment discussed below, no exogenous thrombin was required to stimulate a sample of platelet rich plasma and corresponding platelets and other factors present within the platelet rich plasma.
[0009] It is therefore an object of the present disclosure to provide a combination comprising a therapeutic amount of autologous platelet-rich plasma that utilizes no exogenous thrombin yet nonetheless facilitates tissue sealing, repair, healing, and wound closure.
[0010] It is still further object of the present disclosure to provide an efficient method to stimulate platelet rich plasma by using steady gas percolation as means to create an active turgid gas/liquid interface, which obviously differs from the resting state gas/liquid interface occuring when the platelet rich plasma is simply exposed to ambient air in an open container.
[0011] It is still further object of the present disclosure to provide a preparation of concentrated platelet-rich plasma using an apparatus that permits ease of application of stimulated platelet-rich plasma to damaged tissue.
[0012] It is still further object of the present disclosure to provide a preparation of autologous platelet-rich plasma in a clinical environment to permit patients who experience acute, chronic, or recurrent wound procedures. Such benefiting procedures would include, but not be limited to, diabetic ulcers, venous, decubitus, surgical dehiscences wounds, bone repair and tissue remodeling in autologous wound care.
[0013] Towards the fulfillment of these and other objects and advantages, the present method relates to a first step of isolating from the patient an amount of whole blood and subjecting the whole blood to treatment with an anti-coagulant agent, followed by a centrifugation or separation process to obtain an amount of platelet-rich plasma. The second step comprises adding an effective amount of anti-coagulant neutralizing reagent. The third step comprises stimulating the platelet-rich plasma by creating a turgid gas/liquid interface. The platelet rich plasma, once properly stimulated following the creation of the turgid gas/liquid interface, will adopt certain characteristics such as increased viscosity and fibrin formation. The fourth step comprises applying the stimulated platelet rich plasma to, or infused within, damaged tissue.
DESCRIPTION
[0014] The first preferred embodiment discussed in more detail below represents a process wherein the first step comprises isolating from the patient whole blood using venipuncture. As part of this isolation, it is preferable to receive the whole blood in a container that is treated with an effective amount of anti-clotting agent such as sodium citrate. Using platelet pheresis equipment, blood sequestration or separation mechanisms, the whole blood is thereafter centrifuged or otherwise processed and thereby separated into generally distinct components; i.e., the platelet-rich plasma, the platelet-poor plasma, and the red blood cell concentrates.
[0015] To initiate the second step, the technician or apparatus isolates the platelet-rich plasma and combines an effective amount of neutralizing agent to counter the effects of the anticlotting agent. Calcium chloride is an effective anti-coagulant neutralizing agent, although other agents may be used interchangeably.
[0016] The third step involves creation of a steady turgid gas/liquid interface by way of percolating through the platelet-rich plasma a steady stream of gas which in turn stimulates the platelet-rich plasma and triggers the transformation of fibrinogen to fibrin. Within a relatively brief period of time, the viscosity of the platelet-rich plasma will increase. Variability in stimulation created by the turgid gas/liquid interface depends upon the volume of platelet-rich plasma when compared to the size of the gas bubbles and the relative speed and rate of percolation of gas through the platelet-rich plasma, although there are generalized parameters, exampled generally thorough the Examples recited herein.
[0017] Following the stimulation of the platelet rich plasma, the platelet rich plasma will become viscous and gelatin-like. Once the platelet rich plasma becomes viscous, it is generally known as a tissue graft. As the fourth step, the tissue graft may then be molded, sculpted, or crafted to fit within, applied to, co-saturated with dried or donor material(s), induced into or applied around various grafts, appliances, tools, apparatus, or other fixtures or dressings used with bone or soft tissue repair, remodeling, sealing or healing a particular wound or tissue injury site or to fill surgical incisions.
[0018] It is generally desirable for platelet rich plasma, once initially stimulated, to transform into a tissue graft in not more than fifteen minutes. Using the process described herein, the desired viscosity of the tissue graft was reliably, and consistently, obtained in less than fifteen minutes. This time period is acceptable for the industry. In fact, using exogenously-applied thrombin concentrations otherwise referenced in U.S. Pat. No. 6,524,568, the formation of the viscous platelet graft occurred also within 15 minutes. Of course, the variability associated with the time it takes for the platelet rich plasma to become first stimulated and when the platelet-rich plasma changes viscosity and form a tissue graft varies from patient to patient, and one cause for such variability appears to be a function of the fibrinogen or platelet levels of the patient. When using the steady percolation method, another source of variability appears to be a function of the size of the gas bubbles and the rate, platelet rich plasma (“PRP”) volume, and speed of percolation.
[0019] In a second preferred embodiment, the goal is to simply remove from the whole blood the majority of red blood cells. It is the inventor's experience that the introduction of red blood cells into a wound exacerbates wound healing. For that reason, the second preferred embodiment contemplates the use of that portion of plasma, platelets, fibrinogen, white blood cells, and other cellular structures, as long as the number of red blood cells is reduced when compared to whole blood. Existing technology permits easy isolation of red blood cells, so this disclosure does not contemplate any one mode of centrifugation, sequestration, filtration or separation process over another; instead, this disclosure contemplates a need to separate out red blood cells from the whole blood to decrease the ill-effects associated with degredation of red blood cells within such damaged tissue once the stimulated tissue graft is applied to the damaged tissue. The activation process in the second preferred embodiment is disclosed in the first preferred embodiment.
EXAMPLE 1
[0020] Whole blood was collected from the antecubital vein in the arm into a container with an appropriate amount of anticoagulant agent, sodium citrate, and processed by centrifugation to sequester platelet rich plasma. The platelet rich plasma was combined with 0.05 cc 10% CaCl per 1 cc of platelet rich plasma in order to neutralize the effects of the anticoagulant. The platelet rich plasma was then gently and steadily bubbled (10 bubbles per second) with Oxygen gas to stimulate the platelet rich plasma. The gas was percolated for fifteen minutes or until the platelet rich plasma converted from a liquid form into a substantially gelatinous form. This entire transformation generally takes less than fifteen (15) minutes. The size of the bubble was an estimated 4 mm in diameter.
EXAMPLE 2
[0021] Using the same procedure in Example 1 to isolate platelet rich plasma, and thereafter treating the platelet rich plama with anti-coagulant neutralizer, the platelet rich plasma was gently and steadily bubbled (1 bubble per second) with Oxygen gas to stimulate the platelet rich plasma. The gas was percolated for up to fifteen (15) minutes, until the platelet rich plasma converted from a liquid form into a substantially gelatinous form. The size of the bubble was an estimated 4 mm in diameter.
EXAMPLE 3
[0022] Using the same procedure in Example 1 to isolate platelet rich plasma and thereafter neutralize the anti-coagulant, the platelet rich plasma was steadily bubbled using a rolling bubble stream (15-50 bubbles per second) with Oxygen gas to stimulate the platelet rich plasma. The gas was initially percolated for two (2) minutes using this rolling bubble stream and then removed, permitting the platelet rich plasma to sit idle in order to facilitate opportunity for the blood components to build the necessary latticework and structural cross-linking and become more viscous. This entire transformation generally takes approximately ten (10) minutes. The size of the bubble was an estimated 4 mm in diameter, although bubbles as large as 1 cm have proven successful.
[0023] Under the three above examples, the tissue graft is uniform across all surfaces and throughout.
EXAMPLE 4
[0024] Whole blood was collected from the antecubital vein in the arm into a container with an appropriate amount of anticoagulant agent, sodium citrate, and processed by centrifugation to sequester primarily platelet rich plasma. The platelet rich plasma was combined with 0.05 cc 10% CaCl per 1 cc of platelet rich plasma in order to neutralize the effects of the anticoagulant. The platelet rich plasma was then gently and steadily bubbled (10 bubbles per second) with Nitrogen gas to stimulate the platelet rich plasma. The gas was percolated for three minutes or until the platelet rich plasma converted from a liquid form into a substantially gelatinous form. This entire transformation generally takes less than fifteen (15) minutes. The size of the bubble was an estimated 4 mm in diameter.
EXAMPLE 5
[0025] Using the same procedure in Example 1 to isolate platelet rich plasma and thereafter neutralize the anti-coagulant, the platelet rich plasma was thereafter divided into two equal quantities and placed in two equal glass beakers, such beakers being designated “first beaker” and the second designated “second beaker.” The first beaker was percolated with Oxygen gas at a rate of approximately 5 bubbles per second for 13 minutes, and the platelet rich plasma in the first beaker thereafter formed a viscous and expected graft material. Over the same duration, the second beaker, exposed simply to ambient air, showed no signs of stimulation, and there were no visible clots or increased viscosity.
[0026] The foregoing examples do not necessarily limit the scope of the disclosure herein, and it is only provided to establish actual step-by-step methods by which the invention herein can be utilized effectively to achieve platelet rich plasma gels without exogneous application of thrombin or other agonist.
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The present disclosure contemplates the creation of an active turgid gas liquid interface as means to stimulate various blood components contained within a blood sample, thereby facilitating the formation of fibrin contained within the blood sample, thereby increasing the viscosity of the sample, with such sample being applied to damaged tissue and facilitating tissue repair or tissue sealing components.
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BACKGROUND OF THE INVENTION
The problems involved with proper watering or irrigation of lawns and gardens are well known to every homeowner. Both manual and automatic systems and devices are available for providing water to the lawn and garden areas.
At present, one of the most available methods of lawn and garden irrigation is that employing a series of water sprinklers strategically located throughout the area to be watered. These sprinklers are in turn connected to a private pump and well or to the local municipal water supply. The disadvantages of such systems are well known to many, especially those who have had them installed and correctly maintained.
In addition to the expense of installation (some systems may cost several thousand dollars) and maintenance, there exist the additional problem areas relating to practical as well as aesthetical considerations. Specifically, the sprinkler systems noted above suffer from water wastage, incomplete watering, breakage and prevention of lawn and garden usage during their operation. Additionally, their appearance is aesthetically disruptive and they may cause rusting and spotting of walls, furniture and other related lawn and garden appurtenances.
SUMMARY OF THE INVENTION
The present invention is directed to an irrigation system which retains all of the advantages of known sprinkler systems, while doing away with substantially all of the disadvantages. The system employs a grid pattern of interconnected flow passages having holes strategically formed therein which is interred beneath the surface of the area to which water, or any liquid, is to be applied. The grid pattern of flow passages is fed through an inlet using a gravity feed from the source of water to the holes. Due to its interment beneath the ground and absence of high pressure, a majority of the problems associated with sprinkler systems are alleviated. Furthermore, because of its simple and almost indestructable nature, it has extremely low installation as well as maintenance costs and may be easily installed by any homeowner. Additionally, the system permits the periodic addition of either pesticides or fertilizers when desired.
In a preferred embodiment of the invention, a grid of interconnected flow passages is formed from two sheets of plastic which are heat sealed about their edges as well as within their center portion so as to form a series of perpendicularly oriented and intersecting lines or flow passages. It is through these passages that the water from a reservoir flows. Located at spaced intervals, and having specifically designed sizes directly proportional to their distance from the grid "inlet", are apertures formed in the flow passages. The apertures permit water within the grid pattern to escape to the soil being watered.
In addition to being inexpensive, relative to both installation and maintenance, the grid pattern of flow passages located beneath the surface of a lawn or garden would not interfere with the area's normal use and could be customized by the user to any area of his property.
Accordingly, it is a primary object and feature of the present invention to provide an irrigation system including a grid pattern of interconnected flow passages which is interred within the ground, the flow passages having apertures formed therein for permitting water or the like, which flows from an above-ground reservoir through a connecting tube to the grid of flow passages, to escape to the ground to be watered.
It is another object and feature of the present invention to provide an inexpensive and easily installed and maintained irrigation system which employs a subterranean distribution mechanism.
It is a further object and feature of the present invention to provide an irrigation system employing a grid system of interconnected flow passages having apertures formed therein for permitting water, which is gravity fed to the grid system from a reservoir, to enter the soil, the grid system being formed of selectively sealed sheets of plastic.
It is still a further object and feature of the present invention to provide a method for manufacturing a sheet of grid patterned flow passages from two superimposed sheets of plastic which are sealed along specific lines to provide a network of closed but interconnected tubes having holes therein which distribute water to the soil in which the grid pattern of flow passages is interred.
Other objects and features of the present invention will in part be obvious and will in part become apparent from the detailed description to follow taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its structure and its operation together with the additional objects and advantages thereof will best be understood from the following description of the preferred embodiments when read in conjunction with the accompanying drawings wherein:
FIG. 1 is a schematic representation of the irrigation system of the present invention;
FIG. 2 is a partial plan view of one portion of the preferred embodiment of the irrigation system shown in FIG. 1;
FIG. 3 is a schematic representation of a number of stations necessary in a preferred method of producing the embodiment of the invention shown in FIG. 2;
FIG. 4 is an alternative embodiment of a portion of the irrigation system of the present invention;
FIG. 5 is another alternative embodiment of a portion of the irrigation system of the present invention; and
FIG. 6 is still another alternative embodiment of the irrigation system of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of this invention, which may be best understood by first referring to FIGS. 1 and 2 of the drawings, is designed for employment with a liquid reservoir shown generally at 10 in FIG. 1. Reservoir 10 may serve as a receptacle for any liquid, such as fertilizers or pesticides, but generally would act as a convenient holder for water. Due to the gravity feed nature of the irrigation system to be described below, reservoir 10 should have more than minimal height above the ground 12 to provide the low feed pressure (less than 15 p.s.i.) necessary in such systems.
A connecting tube 14 is located between the reservoir 10 and the distribution mechanism of the present invention. Tube 14 may take any convenient configuration such as rubber hosing or the like. However, due to its partial interment within ground 12, it should preferably be made from a plastic material such as vinyl chloride in order to prevent its corrosion or rusting. The tube 14 is connected, in turn, to a water distribution grid 16 which is located wholly beneath the ground 12.
The water distribution grid 16, while it may take a variety of configurations is, in the preferred embodiment, formed having a generally perpendicularly oriented series of flow passages or the like so as to form a generally rectangular shaped grid. The grid 16 shown in FIG. 1 may be of any convenient size having dimensions x and y with the only limitations being weight considerations relating to moving and installation.
Looking to FIGS. 2 and 3, there is shown a portion of a preferred embodiment of the distribution grid 16 of the present irrigation system and the apparatus for manufacturing the preferred embodiment. As seen in FIG. 2, grid 16 is formed having a plurality of perpendicularly oriented flow passages 18 and 20. Positioned between adjacent flow passages are voids 22 having a generally rectangular shape which, as they are not functional, are removed to permit root growth and drainage of rainfall. Located about the top and bottom portions of the periphery of distribution grid 16 is an edge flow passage 24. Similarly, lateral edge flow passages 26 are provided at each lateral end of the grid. Provided in one convenient corner or edge of the grid is an opening 28 which, in conjunction with a regulation gauge 15 connected on tube 14, permits a controlled flow of water to enter the grid 16 and flow through the passages 18 and 20. An adapter plug 30 is configured to interface between opening 28 in grid 16 and the end 32 of tube 14. Additionally provided along the whole of grid 16 of flow passages 18, 20, 24 and 26 are a plurality of holes or apertures 34 for permitting the exit of the liquid being conveyed from the grid 16. Due to the variety of parameters involved, e.g., flow patterns, frictional loss, drainage and moisture-holding capacity of the soil, there must be a counterbalancing factor which can equalize the parameters thereby providing for substantially even distribution of the liquid. One way of achieving such balance is by varying aperture size and/or spacing. The specific circumstances presented in a given irrigation application will obviously affect the above-noted size and/or spacing to a large degree. However, for the majority of average irrigation applications, it should be noted that the holes or apertures which are closest to the opening 28 will have a smaller size than those farther from the opening, thereby equalizing factors of flow and frictional loss. It should be noted that other factors, when present, will add additional changes to hole size and configuration. Such changes may be made in the field or may be made, at least in part, during manufacture.
FIG. 3 is a schematic representation of the steps and apparatus involved in the manufacture of the distribution grid 16. The distribution grid 16 is formed, at least in the preferred embodiment, from two superimposed plastic sheets 36 and 38 which are coiled upon two separate storage rollers 40 and 42. Plastic sheets 36 and 38 may be of any one of a variety of plastics suitable for interment below ground. Several, such as polyethylene or vinyl chloride, have been found to not only exhibit good static properties which resist deterioration, but in addition, have very low moisture absorption and exhibit low coefficients of friction for not appreciably interferring with water flow with the flow passage. Moreover, such plastics may be made flexible without excessive heating, remain suitably rigid at ambient temperatures, and do not become brittle even at temperatures approaching -60° F.
The two sheets 36 and 38 are superimposed and are pulled through an edge sealing device 44 which, in the preferred embodiment, is composed of two separate rollers 46 and 48 which seal the peripheral edges 50 and 52 of the grid 16. In this regard, seal 52 may be considered an end seal, although this difference is simply one of semantics. The entire periphery of the two superimposed sheets 36 and 38 is thus sealed, leaving only opening 28 in a non-sealed state. It should be noted that a variety of sealing methods such as cementing, heat sealing or ultrasonic welding may be employed to "seal" the two sheets together. Any of such methods, or any other sealing methods, may be employed which causes a watertight seal in both this sealing operation and the one which is about to be described.
Subsequent to edge sealing, the two sheets are "internally" joined or sealed at a sealing station 54 which seals the two sheets together about the rectangular or square-shaped area defined by lines 56 as shown in phantom in FIG. 2. The sealing station 54 may include only a single block which must be repeatedly moved about the two sheets, or it may selectively seal the entire area within the edge seals to form the grid patter of interconnected flow passages shown in FIG. 2. It should be noted that the only difference between the two systems is one of manufacturing convenience. After sealing, the next step is the making or forming of apertures or perforations 34 in the flow passages 18, 20, 24 and 26. This is achieved by a perforator mechanism 66 which may take a variety of configurations. However, one involving a pin 68 is shown which selectively pierces one or both of the plastic sheets to provide exit holes for the water.
After the two sheets have been selectivey joined and pierced, the areas within the lines 56 which are no longer a functional portion of the distribution grid 16 due to their position "outside" of the functional flow passages 18 and 20, 24 and 26, are removed at a die cutting station 58. Station 58 includes a punch mechanism 60 and a die element 62 which remove the square or rectangular-shaped sheet material between the flow passages thus leaving the void 22. The die cutting station removes material along the lines 64 which lie within the sealing lines 56, thereby leaving sufficient material between the two for preventing accidental interference with the sealing lines. Additionally, it should become evident that the removal of the sheet material lying within the die cut lines 64 is a convenience for weight reduction and material usage. Moreover, the removal of such sheet material provides the open spaces in the sheet which permit proper drainage and does not interfere with root growth.
The final step involved in manufacture is conveniently storing the sheet material on rollers or coilers (not shown) for subsequent shipping to the user. While such sheet material may be made in standard widths and lengths, which afford convenience to the user, it should be obvious that the mere employment of a "home" sealer would be all that would be necessary to "customize" the sheet of distribution grid to one's own lawn and garden.
Looking to FIGS. 4-6, there are shown a few alternative embodiments by which the present irrigation system may in part be practiced. FIG. 4 illustrates a small portion of a liquid distribution grid which utilizes a plurality of horizontally and vertically oriented hollow plastic tubes 68 and 70, respectively, which are flowably interconnected through four-way connectors 72 made from plastic or the like. The grid system of interconnected flow passages 68 and 70 might be constructed in convenient sizes in a factory, or may be constructed by the user to fit the specific configuration of his lawn or garden. Holes such as at 74 would be provided for permitting exit of the water from the grid system in the same manner as holes 34 did in the preferred embodiment.
FIGS. 5 and 6 show various ways of automatically forming holes or apertures in the flow passages of the preferred embodiment of the grid system seen in FIG. 2 alleviating the specific need for the aperture maker 66. In particular, FIG. 5 shows the formation of apertures 76 in the flow passages by selectively interrupting the sealing station operation at certain points along lines 56 to create sealing voids for allowing water or the like to escape from the flow passages through the aperture 76 and into the ground. Moreover, FIG. 6 shows the formation of holes or apertures 78 in the flow passages (which may include passages 18 as well as passages 20) by modifying the die cutting operation such that "bites" 80 are selectively taken out at the same time as the die-cut along lines 64. This operation would create interferences with the flow passages and thereby result in the formation of holes 78 as is shown in FIG. 6.
It will be seen that by this invention there is provided a much improved irrigation system employing a distribution grid formed of a plurality of interconnected flow passages which is interred within the ground. The system is fed from a liquid reservoir, which may be automatically filled or not, and which may be inconspicuously located beside the house. The irrigation system does not interfere with plant growth or usage above the surface and would be constructed and configured to withstand temperature extremes. Due to its basic and simple structure, the system would be within the pocketbook of any homeowner who is willing to install it himself or within most pocketbooks if someone else is hired for the installation. Customizing and fitting the system to any particular tract of land insures adequate watering or liquid application without the wet walkways, stained walls, and maintenance expenses which are part of an above-ground sprinkler system.
This invention may be practiced or embodied in various other ways without departing from the spirit or essential character thereof. The preferred embodiments described herein are therefore illustrative and not restrictive, the scope of the invention being indicated by the appended claims and all variations which come within the meaning of the claims are intended to be embraced therein.
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An irrigation system employing, in part, a coarse screen or grid of flexible material having internal interconnecting passages for the flow of water or the like therethrough, the grid beng interred under the area of ground which is to be watered. Orifices are distributed along the interconnecting passages to release the water by gravity feed from a source or reservoir.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. §119(e) from co-pending U.S. Provisional Patent Application No. 62/153,580, by Cynthia Lundberg, “Variable Aperture Flow Control Mechanism for Gas Lift Valves” filed 28 Apr. 2015, which, by this statement, is incorporated herein by reference for all purposes.
BACKGROUND OF THE INVENTION
[0002] The throttling mechanisms of self-contained Gas Lift Valves (GLVs) for artificial of oil or liquid loaded gas wells have either been a fixed aperture design (e.g. orifice or venturi) or have variable throttling by obstructing the fluid flow path through a fixed aperture (e.g. ball and seat), commonly with a gas charged bellows actuating the throttling mechanism.
[0003] The fixed aperture design cannot be used as an unloading valve (which requires it lose under certain conditions) and can only be used as an operating valve (continuous injection). The fixed aperture allows only limited flexibility to vary injection flow rate and well conditions without resulting in well instability. For any change in desired injection rate, the optimal solution is a corresponding change in the injection valve aperture; however any fixed aperture valve does not allow this without removal and replacement of the valve.
[0004] The variable throttling design utilizes a pressure difference (between bellows charge pressure, injection/casing pressure, or production/tubing pressure) opposed by a spring force (bellows metal spring force and/or coil spring force) to set the throttling device position.
[0005] Because the gas flow path is in the same axis as the flow obstructing throttling device (commonly a stem and ball), the gas supply (casing) and production (tubing) pressure affect the net forces applied to the throttling device—and in a varying manner, depending upon the throttling device position (how far open or closed) and the process conditions.
[0006] The effectiveness of Gas Lift Valves (GLVs) for artificial lift of oil and liquid loaded gas wells is hampered by the Production Pressure Effect Factor (PPEF) for Injection Pressure Operated (IPO) valves and the Injection Pressure Effect Factor (IPEF) for Production Pressure Operated (PPO) valves. Because current designs utilize an unbalanced (not pressure/force balanced) throttling mechanism, PPEF or IPEF are inherently non-zero and adversely affect the performance of the valves.
[0007] Existing designs are inherently unstable during opening and closing, and are not well suited for continuous throttling service. They tend to “pop” open and closed rather than smoothly transition from closed to open, and visa verse.
[0008] This invention provides varying flow capacity through varying the flow aperture, without affecting the actuating mechanism pressure/force balance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 illustrates a variable aperture flow control mechanism with a fully open aperture, reduced aperture, and fully closed aperture in accordance with an exemplary embodiment of the invention.
[0010] FIG. 2 illustrates a bellows actuated gas lift valve with pressure balanced variable aperture throttling mechanism in accordance with an exemplary embodiment of the invention.
[0011] FIG. 2A illustrates the housing of a bellows actuated gas lift valve with pressure balanced variable aperture throttling mechanism in accordance with an exemplary embodiment of the invention.
[0012] FIG. 2B illustrates the moving sleeve of a bellows actuated gas lift valve with pressure balanced variable aperture throttling mechanism in accordance with an exemplary embodiment of the invention.
[0013] FIG. 3 shows a differential pressure actuated gas lift valve with variable aperture throttling mechanism in accordance with an exemplary embodiment of the invention.
[0014] FIG. 3A shows an external view of the housing of a differential pressure actuated gas lift valve with variable aperture throttling mechanism in accordance with an exemplary embodiment of the invention.
[0015] FIG. 3B shows an external view of the cage of a differential pressure actuated gas lift valve with variable aperture throttling mechanism in accordance with an exemplary embodiment of the invention.
[0016] FIG. 3C shows a cutaway view of the housing of a differential pressure actuated gas lift valve with variable aperture throttling mechanism in accordance with an exemplary embodiment of the invention.
[0017] FIG. 3D shows a cutaway view of the cage of a differential pressure actuated gas lift valve with variable aperture throttling mechanism in accordance with an exemplary embodiment of the invention.
[0018] FIG. 3E shows a cutaway view of the spring engaging sleeve of a differential pressure actuated gas lift valve with variable aperture throttling mechanism in accordance with an exemplary embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] This invention is an improvement on what currently exists. The throttling mechanism is oriented such that the size of the aperture through which fluid is directed is varied in proportion to the desired output. The sealing and opening of the aperture is accomplished by an actuating force oriented perpendicularly to the fluid pressure differential created as pressure in the valve is throttled down or up. This minimizes the effect of pressure fluctuations on the opening and closing of the valve, as the fluctuations are no longer directed in opposition to the actuating force.
[0020] In the orientation of FIG. 1 , actuating force is applied vertically while fluid. pressure/force acts horizontally. For a three dimensional cylinder construction, actuating force is applied axially while pressure/fluid force acts radially.
[0021] In the embodiment shown, fluid enters the valve by flowing through the variable flow aperture ( 2500 ) into the stationary cage ( 2300 ) and exiting via the bottom port connection ( 2215 ). The variable flow aperture ( 2500 ) is throttled via use of a moving sleeve ( 2400 ) which is oriented so that its movement is directed perpendicular to the fluid pressure gradient.
A. Bellows Actuated Valve:
[0022] Two embodiments of the innovation employ bellows actuation, where the bellows is exposed to the Injection Pressure [Injection Pressure Operated (IPO) valve] or the bellows is exposed to the Production Pressure [Production Pressure Operated (PPO) valve]. As stated above, the effectiveness of Gas Lift Valves (GLVs) for artificial lift of oil and liquid loaded gas wells is hampered by the Production Pressure Effect Factor (PPEF) for IPO valves and the Injection Pressure Effect Factor (IPEF) for PPO valves.
[0023] The sleeve and cage act together to provide a varying aperture available for fluid flow based upon the housing/bellows pressure, unaffected by valve differential pressure. A dynamic seal is created by the inclusion of a vented section between the cage and the housing. The vented section is in communication with the housing and bellows assembly. As the aperture is opened, more fluid exits the aperture, increasing the housing and bellows assembly pressure. From the housing and bellows assembly, fluid flows into the vented chamber. As fluid enters and exits the vented chamber the moving sleeve shifts position, varying the size of the aperture. The end result is a dynamic seal which opens as pressure drops and closes as pressure increases, dynamically throttling the flow of fluid and negating the opposing PPEF or IPEF such that the PPEF or IPEF is effectively zero.
[0024] In the embodiment shown, the bellows actuated valve ( 2000 ) has a moving sleeve with a bellows connection end ( 2400 ) which fits within a housing ( 2200 ) having a bottom port connection end ( 2210 ). The bottom port connection end also fulfills the function of and serves as a cage ( 2300 ). Between the sleeve ( 2400 ) and the cage ( 2300 ) is a vented volume ( 2310 ). The vented volume ( 2310 ) is vented to the valve via a venting opening ( 2320 ). FIG. 2A shows a cutaway section of the stationary cage and housing ( 2300 & 2200 ). FIG. 2B shows a cutaway section of the moving sleeve ( 2400 ) including the path ( 2320 ) by which the vented volume ( 7310 ) vents to the valve.
B. Differential Pressure/Spring Actuated Valve:
[0025] Another variation of this invention is actuation by differential pressure across the valve, opposed by a spring force. In the embodiment shown in FIG. 3 , a sleeve containing a compression spring slides over an extension of the stationary cage, varying the aperture available for fluid flow. The inner section of the sleeve is exposed to outlet pressure through a pressure equalizing hole in the stationary cage. High inlet pressure pushes the sleeve downwards, reducing the outlet aperture. The movement of the sleeve to reduce aperture is opposed by the compression coil spring, which is pressed against the stationary cage as the outlet aperture is covered. As such, If inlet pressure is low, the sleeve extends upwards to cover the let aperture, stopping flow until pressure reaches a level sufficient to overcome the spring force. Thus, the sleeve is shunted between covering the inlet aperture and outlet aperture dictated by the pressure differential between the inlet and outlet pressure. Springs with different spring constants or stationary cages of varying dimensions may be used in the valve to dictate the pressure at which flow is throttled. In another embodiment, the spring providing spring force in opposition to the pressure differential may be external to the valve, allowing the use of larger springs which would potentially be too large to fit within the valve.
[0026] In the embodiment shown, the spring actuated valve ( 3000 ) contains a housing ( 3200 ) having a bottom port connection end ( 3210 ), where the housing ( 3200 ) is connected to a cage ( 3300 ) at the bottom port connection end ( 3210 ). A spring engaging sleeve ( 3400 ) is located within the volume created by the joining of the housing ( 3200 ) and the cage ( 3300 ). The spring engaging sleeve ( 3400 ) contains a compression spring ( 3100 ) with a set tension corresponding to the desired throttling effect.
[0027] For low or reverse differential pressure applied to the valve, the spring engaging sleeve ( 3400 ) contacts the housing ( 3200 ) sealing the flow path and preventing flow in the backward direction (back flow). This is a flow checking action.
[0000] As pressure differential increases, the flow path is opened and fluid flows through the annulus between the housing ( 3200 ) and sleeve ( 3400 ), flows through the flow aperture ( 3310 ), and exits through a bottom port connection ( 3215 ). As pressure differential further increases, the pressure forces compress the spring ( 3100 ) and the sleeve lowers in position to reduce the aperture available for the outlet flow path. This is a variable aperture, inversely related to the differential pressure applied. When the pressure differential is high enough to compress the spring ( 3100 ) such that the sleeve contacts the base of the cage ( 3300 ), the flow path is sealed and outlet flow is blocked.
[0028] In another embodiment, the compression spring ( 3100 ) controlling the throttling of the valve may be external to the housing ( 3200 ), allowing for springs of varying size to be used.
How to Make the Innovation:
[0029] For a cylindrical valve form, construct the flow control mechanism with fluid flow path inward or outward radially and a cylindrical sleeve which moves axially to cover varying portions of the flow path aperture, resulting in an effective variable aperture for flow.
A. Bellows Actuated Valve:
[0030] For a bellows actuated valve, the bellows assembly is connected to the moving cylindrical sleeve. A dynamic seal between the stationary cage and moving sleeve, combined with one or more vent holes above the seal, produces a pressure balance in the axial direction resulting in PPEF or IPEF of zero.
B. Differential Pressure/Spring Actuated Valve:
[0031] For a differential pressure actuated valve, the moving sleeve is constructed with a top seal (no vent hole) and the stationary cage is constructed with a hole which equalizes the pressure under the closed sleeve with the valve outlet pressure. Pressure force acting on the moving sleeve results from the inlet pressure and outlet pressure applied over the sleeve top area. This pressure force is countered by a compression spring, which results in the sleeve axial position proportional to the differential pressure applied divided by the compression spring constant. The resultant aperture available for the flow path is inversely related to the differential pressure, and becomes zero (fully closed) when the force from differential pressure is greater than the force with the spring fully compressed (to sleeve closed position).
How To Use The Innovation:
A. Bellows Actuated Valve:
[0032] The innovation can be applied to any form of IPO or PPO Gas Lift Valve (tubing retrievable, wireline retrievable, or other variant). The variable aperture flow control mechanism is coupled to any industry standard GLV bellows assembly, with the bellows connected to the moving sleeve to provide actuation.
B. Differential Pressure Spring Actuated Valve:
[0033] The innovation can be used as an unloading gas lift valve, actuated by differential pressure. The purpose of an unloading valve is to inject gas only until conditions are such that a valve lower in the well is capable of injection, at which point the unloading valve should close.
[0034] The diagrams in accordance with exemplary embodiments of the present invention are provided as examples and should not be construed to limit other embodiments within the scope of the invention. For instance, heights, widths, and thicknesses may not be to scale and should not be construed to limit the invention to the particular proportions illustrated. Additionally some elements illustrated in the singularity may actually be implemented in a plurality. Further, some element illustrated in the plurality could actually vary in count. Further, some elements illustrated in one form could actually vary in detail. Further yet, specific numerical data values (such as specific quantities, numbers, categories, etc.) or other specific information should he interpreted as illustrative for discussing exemplary embodiments. Such specific information not provided to limit the invention.
[0035] The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.
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This invention is a flow control mechanism for self-contained Gas Lift Valves (GLVs) for artificial lift of oil or liquid loaded gas wells. This invention is an improvement on what currently exists. Rather than obstruct the flow by partially or fully obstructing a fixed aperture (commonly a stem/ball and seat), where the fluid pressure and dynamic forces affect the actuating force; this invention applies the actuating force to a variable aperture flow control mechanism, for which fluid pressure and dynamic forces do not affect the applied actuating force.
By orienting the fluid pressure gradient and resultant applied force perpendicular to the actuating force and action, fluid throttling by changes in available aperture does not affect the actuating force applied to the variable aperture device. Actuating force is applied vertically while fluid pressure/force acts horizontally. For a three dimensional cylinder construction, actuating force is applied axially while pressure/fluid force acts radially.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] The subject matter of this continuation-in-part patent application is related to the subject matter of the continuation-in-part application having Ser. No. 10/815,533, which was filed on Apr. 1, 2004, which claims priority to the non-provisional patent application Ser. No. 10/411,551 which has a filing date of Apr. 10, 2003, which claims priority to the provisional patent application having Ser. No. 60/371,441, which was filed on Apr. 11, 2002, and is owned by a common assignee.
BACKGROUND OF THE INVENTION
[0002] This invention relates principally to a building block, one that is constructed, generally of waste material, such as fly ash, and can be either extruded or compressed under pressure into the fabrication of a building block for constructing buildings or the like.
[0003] There are numerous building blocks that are available in the art for use for the construction primarily of commercial industrial type of buildings, and even some blocks are used for constructing residential homes, as known. For example, most of these blocks are fabricated from concrete, poured into a form, left to cure, and then removed and allowed to dry, in preparation for usage. Blocks of this type, generally of concrete, can be formed in a variety of shapes.
[0004] Various prior art types of blocks, usually of the molded type, can be seen in the prior patent to Haener, U.S. Pat. No. 5,822,939, identified as An Insulated Building Block System. The patent to Putnam, U.S. Pat. No. 2,319,345, discloses another type of Fabricated Building Block. The patent to Crespo, U.S. Pat. No. 4,514,949, shows an Interlocking System for Building Walls, and it should particularly be noted that the shown block includes openings, and through which reinforcing rods may locate, during building construction. The patent to Schmall, U.S. Pat. No. 513,423, discloses another form of Building Block. The patent to Sherwood, U.S. Pat. No. 5,715,635, discloses a Building Block Unit and Method of Manufacturing the Same. This includes an interlocking type of feature that can hold the blocks together, even perhaps without connecting mortar. The patent to Stenekes, U.S. Pat. No. 6,065,265, shows A Corner and End Block for Interlocking Building Blocks System.
[0005] The patent to Hancock, U.S. Pat. No. 3,355,849, shows a Building Wall and Tapered Interfitting Blocks Therefore. Another patent to Hancock, U.S. Pat. No. 3,936,989, shows an Interlocking Building Type of Block That Can Be Fabricated into a Wall System, even perhaps with or without the use of mortar. U.S. Pat. No. 4,126,979, to Hancock, shows another Interlocking Form of Building Block.
[0006] The current invention is designed to provide for the construction of a building block, by a variety of methods, but one which does not rely on cement as it utilizes extensively what are currently considered as wood substitutes: wood chips, sawdust, textile waste, and fly ash, among other things.
[0007] For example, the United States patent to Strabala, U.S. Pat. No. 5,534,058, discloses a structural product fabricated from waste materials, and its method of making the same. The product includes as ingredients fly ash, cellulose-based material, and an adhesive binder for holding these ingredients together. The patent states that the mixture is particularly useful for forming structural products such as bricks, panels, roof shingles, studs, and the like. More specifically, the patent defines that the structural product, which may also be formed into blocks, comprises a substantially homogeneous blend from seventy to eighty five percent (70 to 85%) by weight of a Class C fly ash, or a mixture of Class C fly ash and Class F fly ash. The mixture further includes about fifteen to thirty percent (15 to 30%) by weight of a cellulose based material, which can be pulp, wood, sawdust, pulverized cardboard, or the like. The block further includes an adhesive binder, which is categorized as an emulsion, even one which can be mixed with water to form a liquid. Preferably the adhesive binder is polyvinyl acetate, which can be added to the mixture as an emulsion. The mixture also includes an inner filler, and such material may include lime, Class F fly ash, or bottom ash, up to about thirty five percent (35%) by weight of the total weight of the mixture.
[0008] The current invention likewise utilizes a fly ash as a primary ingredient, but varies substantially from what is identified in the Strabala patent, utilizing either a molding or pressure application to form its composite blocks, for use for a related purpose: construction.
[0009] Other prior art patents identifying the use of fly ash, as an ingredient for forming insulating and ceramic materials, and the like, include the patent to Sicka, U.S. Pat. No. 3,625,723, for Foamed Ceramic Comprising Fly Ash and Phosphoric Acid. U.S. Pat. No. 1,608,562, to Melandri, defines the Manufacture of Building Blocks, Slabs, Floors, Ceilings, Tiles, and the Like, from a mixture of fibers and cementous material, and hydrated lime. The patent to Halwani, U.S. Pat. No. 5,504,211, describes a Lightweight Block Containing Stabilized Wood Aggregates. The patent to Riddle, U.S. Pat. No. 5,366,548, explains the use of Volcanic Fly Ash and Kiln Dust Mixtures, and a Process for Making Articles Therefrom. The patent to Patterson, U.S. Pat. No. 5,350,451, explains a Building Material Made From Waste Paper and a Method for Producing the Same. The patent to Wada, et al., U.S. Pat. No. 5,154,771, explains a Hydraulic Inorganic Mixture and Molded Articles Thereof. The patent to Lempfer, et al., U.S. Pat. No. 5,102,596, explains the Method of Producing Shaped Articles of Fiber/Binder Mixtures. The patent to Elias, U.S. Pat. No. 5,048,250, shows another type of Building Block. The patent to Vinson, et al., U.S. Pat. No. 4,985,119, shows a Cellulose Fiber-Reinforced Structure. The patent to Baes, U.S. Pat. No. 4,840,672, explains that Lightweight Insulating Boards and Process for Manufacturing the Same. The patent to Costopoulos, et al., U.S. Pat. No. 4,659,385, shows a Building Material Manufacturing from Fly Ash. The patent to Barrable, U.S. Pat. No. 4,132,555, explains a Building Board. Finally, and lastly the patent to Nutt, U.S. Pat. No. 3,753,749, shows other Concrete Mixtures.
SUMMARY OF THE INVENTION
[0010] This invention relates primarily to the construction of a unique building block, one fabricated totally from waste materials and without a binding agent, and a number of systems by which the block may be fabricated and molded, into a high strength finished product. This invention contemplates three aspects relating to its concept: initially, the formulation and type of building block constructed, and two methods or systems by which the block may be fabricated, in preparation for usage.
[0011] Essentially, the building block of this invention can be fabricated of the open cavity type, but preferably, is constructed into the configuration of a solid block, thereby providing it with greater strength and less susceptible to fracture, because of the solid integrated nature of its construction. Because of the type of waste materials from which the block is fabricated, including wood pulp, or the like, the block will accept and hold a nail, screw, or the like, so that supplemental sheeting, rather exteriorly or interiorly, can be applied and held directly to it, during fabrication of a building. Furthermore, because of the inherent nature of its ingredients, it can also be subject to cutting by a power saw, or the like. In addition, the block of this invention, because of its mixture, has enhanced thermal resistant characteristics, as can be understood. In addition, it can be treated, with other ingredients, such as a boride, to render it termite and mold resistant. It can function as a sound insulation; even can be used as a sound wall in or near high-noise areas, like at airports and industrial parks, and as dividing walls for adjacent condominiums and apartments, to provide that type of insulation.
[0012] Significantly, the block of this invention has high strength and a large load bearing capacity due to its solid configuration, and obviously provides safety during usage, lowers energy bills, and as previously alluded to, is fabricated from generally waste ingredients, meaning that it will be low cost in construction. The block is made generally of about ninety nine percent (99%) waste materials, and therefore, is earth-friendly as a “green” building material, as can be understood.
[0013] In the preferred embodiment, the block may be constructed having dimensions generally in the category of nine and ½ inches high, eight inches deep, and seventeen and ½ inches wide (9.5″×8″×17″) including the tongue and groove jointed edges. Obviously, other dimensions can be readily applied during fabrication of the blocks of this invention.
[0014] Generally, the formulae for the compressed or extruded blocks of this invention are designed to provide maximum usage of waste material, such as fly ash, as known in the art, without cement or other binder. For example, where it is desired to fabricate a block having dimensions generally within the range of nine and ½ inches by eight inches, and to any length (9.5″×8″×any length), depending upon the mold, it will include a Class C Fly ash in a range of about fifty percent (50%) to ninety percent (90%) by weight of the formulated block. Wood pieces or cellulose materials, such as chips or chunks, may be applied in the vicinity of ten percent (10%) to fifty percent (50%) by weight of the mixed formulation. Optionally, boron, or a boride, may be added in the range of one half percent to five percent (½% to 5%), in order to furnish the mold retardency and as a preventer of insect infestation, characteristics which are desirable particularly since the formulation of this invention includes ground wood ingredients, as previously explained. Class C fly ash is readily available in abundance from the many coal fired electric generating plants. In an alternate embodiment for the military, Portland cement may be added in a range of about two to twenty percent (2% to 20%), for ballistic or hardening purposes.
[0015] Other ingredients that may be used effectively in addition to fly ash include wood, wood ash, sugar beat wast lime, rice straw, wheat straw, cotton stalks, sugar cane, bamboo, sea shells, sand, river sand, quarry sand, and desert sand, all of which may be used as wood substitutes, to add further strength to the mixture, from between ten percent (10%) to thirty percent (30%) by weight, thereby reducing the amount of fly ash that may be necessary in the mixture, or for reducing the wood chip ingredient, in order to provide enhanced strength to the blocks, when formed, as can be understood. Obviously, the greater the quantity of sand or other granular material that is added to the block, reduces the wood pulp content, makes the block less isolative, and reduces the ability of the finished block to accept and hold a nail and a screw, when applied during the construction of a building.
[0016] Two other essential ingredients for the mixture for forming the building block of this invention includes the addition of a Plasticizer agent to the composition, during its mixing, for the purpose of providing a dispersion of the mixed components within the ingredients, including water, that results in a more thorough mix of the ingredients, and allows for their better flow ability, during the deposit of the formal into the forms. In addition, an accelerator is useful for re-acting the fine particles of the mixture with all of the other ingredients, during mixing, so as to more quickly and better form the slurry for addition to the forms, during molding of the blocks.
[0017] The system of manufacturing the blocks of this invention includes the extruding method, which incorporates a cyclone wood chip hopper, into which the chips may be placed, and in which hopper the fly ash from an outside silo may be delivered, to provide for the proper mixing. A variable speed feeder may be used to deliver the mixture to a pre-mixer, wherein treated water may be added, and a displacement compressor provides the necessary pressure on the mixture, as it is delivered to a variable speed extruder, that may extrude a continuous block, to desired cross sectional dimensions, such as nine and ½ inches by eight inches (9.5″×8″), but to any length. Such lengths may even be as great as four feet to sixteen feet long (4′ to 16′), for the extruded block, exiting from the extruder. The block may then be conveyed to another location for drying, curing, and storage, before it is shipped to the building site, for usage.
[0018] The preparation of the compressed block may be achieved through the usage of a hydraulic press, which exerts a ram force upon the block ingredients, delivered to the site of compression, where the blocks are instantly formed under modest pressure, into individual blocks, to dimensions as desired, and then exit the compression chamber by way of a conveyer, to a remote location for further drying and curing, or for storage until usage. The type of modified hydraulic press, that has found usage for the purposes of building the blocks of this invention, may be obtained from Vermeer Manufacturing Company, of Pella, Iowa, or a related type of hydraulic or other press.
[0019] It is, therefore, the principle object of this invention is to provide a unique building block that can be instantly manufactured for low cost from generally waste ingredients and materials.
[0020] Another object of this invention is to provide a molded, even one constructed under pressure, building block to a variety of dimensions, at the selection of the builder, and the owner.
[0021] Yet another object of this invention is to provide a building block that has retention attributes, and can hold a nail or screw, upon application.
[0022] Still another object of this invention is to provide a building block that may be fabricated having various grooves, in order to allow the locating of reinforcing bars, utility conduits, or the like.
[0023] Still another object of this invention is to provide a building block having a solid surface, and not necessarily made of the cavity type prior art block, and therefore exhibits a much larger load-bearing capacity than other type of fabricated blocks.
[0024] Still another object of this invention is to provide a building block that has a high fire resistance rating.
[0025] Another object of this invention provides a building block that will be insect and termite resistant because wood is a major ingredient, as organic inhibitors or coatings provide high resistance to insect infestation.
[0026] Still another object of this invention is to provide a building block having a high wood chip and piece content.
[0027] Another object of this invention is to provide a building block that may be held together without cement or other pozzollans, and does not necessarily require the usage of any mortar as normally used and required between blocks in typical applications.
[0028] Another object of this invention is to provide a building block that exhibits thermal insulation value in the range of R-16, and higher.
[0029] Still another object of this invention provides a building block that has excellent noise suppression benefits.
[0030] Yet another object of this invention is to provide a building block that eliminates the need for the stud-wall framing, and insulation batting. This can be achieved, because the building block already has good thermal insulation, and its wood content allows the builders to nail or screw the exterior and interior sheeting and other framing members, directly to the manufactured wall.
[0031] Another object of this invention is to provide a building block for use for constructing walls, which in certain jurisdictions, are already approved for general building usage.
[0032] Another primary object of this invention is to provide a sustainable building product, being composed primarily of waste materials. Hence, it provides a method by which waste material may be disposed of and utilized, without filling the landfills, with such waste material. For example, agricultural waste, logging waste, or even broken or waste wood pallets which can be chipped, can be used for the purpose of fabricating the blocks of this invention.
[0033] Another object of this invention is to have an appearance that does not reveal the ingredients used in the invention.
[0034] Another object of this invention is to form a block without any adhesive material mixed therein.
[0035] Another object of this invention is to improve the hydration of the mixture which results in a faster and more thorough chemical reaction of the components of the present invention.
[0036] These and other objects may become more apparent to those skilled in the art upon review of the invention as described herein, and upon undertaking a study of the description of its preferred embodiment, when viewed in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] In referring to the drawings,
[0038] FIG. 1 provides an isometric view of the fabricated building block of this invention;
[0039] FIG. 2 is a schematic view of the system for processing by compression of the building blocks of this invention; and,
[0040] FIG. 3 is a schematic view of a portable hydraulic press utilized occasionally for the pressure forming of the blocks of this invention.
[0041] The same reference numerals refer to the same parts throughout the various figures.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0042] In referring to the drawings, and in particular FIG. 1 , the example of the type of building block fabricated by the system of this invention is readily disclosed. The building block 1 will be of standard shape or appearance, but can be fabricated to any size, but generally may be in the range of four inches high, eight inches wide, and twelve inches in length (9½″×8″×17½″). Obviously, other dimensions may be used for the block of this invention, and depending upon which system is used to fabricate the blocks, as for example, in the extruded block, a block of any length, such as sixteen feet (16′) as previously stated, could be developed. Or, where the block is molded by hydraulic pressure, it may have a shape and proportions similar to those as shown in FIG. 1 . In addition, the block may be molded or extruded having supplemental configurations, such as the upper tongue 2 and lower groove 3 , and end grooves 4 , as noted. Preferably, the legs 5 will be greater than 2″ each to provide structural strength to the areas of the block. The purpose of these grooves is to provide clearance, either for locating reinforcing bars or perhaps conduits that may extend through the wall and through which electrical wires, heating ducts or other types of utilities may be located. The preferred embodiment has a chamfered and protruding top or tongue and a matching bottom or groove.
[0043] The formulation for the block of this invention can be seen from the tables hereinafter provided.
TABLE I Extruded industrial blocks 9.5″ × 8″ × any length Class C fly ash from 50% to about 90% Ground wood from 10% to 50% Boron from ½% to about 5%
[0044]
TABLE II
Compressed industrial blocks 9.5″ × 8″ × 17.5″
Class C fly ash from 50% to 90%
Portland cement 2% to about 20%
Ground wood from 10% to about 50%
Boron from ½% to about 5%, or
[0045]
TABLE III
Compressed industrial blocks 9.5″ × 8″ × 17.5″
Class C fly ash from 50% to about 90%
Ground wood from 10% to about 50%
Boron from ½% to about 5%
[0046] Water is applied in all these formulations from 15% up to 25%.
[0047] Plasticizer or water reducer is added to each of these tables approximately 0.5 to 30.0 oz. per hundredweight of fly ash in the mixture.
[0048] Accelerator is added to each of these tables approximately 0 to approximately 32 oz. per hundredweight of fly ash in the mixture.
[0049] These formulae are supplemented by a plasticizing or a water reducing agent, and an accelerating agent. A plasticizer increases the slump of the mixture and raises the viscosity of the mixture which improves the flow characteristics of the material, generally at low water levels in the mixture. Plasticizers such as preferably PLP from W.R. Grace & Co. of Cambridge, Mass., and alternatively Sika 6100 from Sika Corp. of Marion, Ohio, Melchem from General Resource Technology, Inc. of Eagan, Minn., and Polyheed FC100 from Master Builders, Inc. of Cleveland, Ohio have also shown a water replacement capability. Generally, the plasticizer provides for heightened dispersion of the mix components within the water resulting in a smooth faced block formed under pressure. More particularly, the plasticizer acts as a hydration agent or a wetting agent that mixes the components more thoroughly, thus reducing the incidence of the mixture balling. The plasticizer improves the ability of water to coat the surfaces of the solid components of the mix on the micro level. On the macro level, the resulting blocks do not reflect on their outside the chunky appearance of the aggregate or other mix components. Rather, the blocks take on the shape and surface texture of their forming chamber.
[0050] A water reducing agent disperses the fine particles of the mixture with less water. The agent enhances the effect of water throughout the mixture. The formulation is made into blocks with less gallons of water per hundredweight of formulation. Lessening the water requirement saves on weight and labor costs during fabrication of blocks. Water reducers such as preferably FC100 from MasterBuilders, and alternately Sika 6100 from Sika have readily reduced the water required in mixtures.
[0051] An accelerator makes the reaction of fine particles with the remainder of the mixture occur more quickly. The mixture solidifies at higher strength more quickly. An accelerator is also useful for low temperature casting where the accelerator augments ambient temperature and returns curing to normal duration from the cold delayed duration. Accelerators such as preferably RAPID-1 from Sika, and alternatively Pozzolith from Master Builders and Polychem Super Set from General Resource Technologies provide for increased strength once the mixture cures.
[0052] The co-action of the plasticizer and the accelerator improve the chemical reaction of the components within the mixture. The chemical reaction occurs faster and a greater amount of the components are reacted while a lower percentage of the components are wasted through non-reaction. Further, these formulae lack a binding agent, except Portland cement for the military formula, and thus the actions of the plasticizer, water reducer, and accelerator upon the mixture, under forming pressure, make a consistent and strong block.
[0053] As can be seen from FIG. 2 , the system for pressing the industrial building blocks of this invention is readily disclosed. As noted, the ingredients for the block are processed by the system, as disclosed. For example, pre-ground wood chips, as at 10 , are delivered by conveyor 11 , to a hammer mill 12 , to provide a secondary grinding or pulverizing of the chips. The ground and pulverized wood will be conveyed by a blower 13 , to a roto-paddle blower 14 , and delivered by conduit tubing 15 , for emitting into the upper end of a cyclone wood chip hopper 16 , as can be noted. Support structure, as at 17 , provides the bracing necessary for structurally holding the system in place.
[0054] From the cyclone wood chip hopper, the ground pulp, which may include wood chips, textile waste, bamboo, rice straw, wheat straw, or any other pulp ingredients, are delivered to a variable speed roto-feeder, as at 18 . Then the proper amount of the wood ingredient is delivered to a pre-mixer 19 , as noted. At this point, and into the pre-mixer, fly ash from an outside silo source 20 is delivered by way of a variable speed auger 21 , through a conduit 22 , to the pre-mixer. The fly ash may be generated and deposited into the silo from any of the sources for this ingredient. For example, it may be the fly ash from power plants or other installations.
[0055] In addition to the delivery of the wood chip component, and the fly ash from external sources, water, by way of the conduit 23 , is also metered into the pre-mixer, to provide some degree of texture that renders the mixture more pliable, and capable of being either extruded, or compressed, as can be understood. A plasticizer 27 and an accelerator 28 are pumped into the mixture for blending with the other ingredients. The amount of the ingredients added, including the treated water, plasticizer, and accelerator, can be determined from the formulations as previously set forth.
[0056] From the pre-mixture, a variable speed mixer further mixes the ingredients, as at 24 , and delivers it to a variable speed or hydraulic press 25 . At this point the blocks will then be conveyed upon the conveyor 26 , to a location of drying, curing, storage, or even for use for installation at a building site.
[0057] As an example of usage of the hydraulic press process, utilizing the system as shown in FIG. 2 , the raw feed stock, such as shredded wood, will be delivered to the plant site, which may be arranged at a landfill location. The wood chips are moved from the receiving hopper via the belt conveyor, as explained, to a hammer mill, where it is ground into small pieces. From there the wood is carried by an air stream to a cyclone, for the purpose of separating the wood from the air, where the wood particles then fall into the hopper. There it is fed via a variable speed auger to a continuous flow mixer, identified as the variable speed mixer.
[0058] Fly ash, such as Class C fly ash, is delivered by bulk truck, to the silo at the plant where the blocks are formed. The fly ash is carried by another mixer, by way of a variable speed auger during the process. The fly ash is generally obtained from coal burning power plants, and delivered in bulk to the silo where it is then delivered to the variable speed auger. In an alternate embodiment for the military, Portland cement by bulk trucks is also provided, in a variation on the formulae, to another silo, where it likewise may be added as an ingredient by a variable speed auger. The alternate embodiment also has a dispersant agent such as Ultra from W.R. Grace or Rheomix from Master Builders that spreads the cement throughout the mixture for even and thorough reaction.
[0059] In the preferred embodiment, calcium borate is delivered to the plant, and is likewise moved to the mixer by way of a variable speed auger. Obviously, the variable speed augers are all used to provide for the delivery of the precise amount of the ingredients, as determined necessary, for formulating the type of blocks to be molded or cast. Ground wood is delivered to the processing plant in bulk trailers. It is blended with ground wood, to provide further bulk. Treated water is injected into the mix blend just before it exits the mixer, on its way to the press. The hydraulic press forces the slurry through a dye, as in the preferred embodiment, yielding a nine and ½ inch by eight inch by seventeen and ½ inch (9.5″×8″×17.5″) block.
[0060] The second method for fabricating the blocks of this invention may be seen from FIG. 3 , which shows a modification to a hydraulic press, which is utilized to compression form the blocks, under hydraulic pressure, although other sources of pressure may be utilized.
[0061] The system for providing a hydraulic or other pressured compression for forming the compressed block of this invention is shown in FIG. 3 . As disclosed, this may be a more portable device. It includes the hydraulic ram machinery, such as shown at 30 , which is a device for providing pressure to a ram, generally under hydraulic pressure, and is available, as previously explained, from Vermeer Manufacturing Company, of Pella, Iowa. This particular hydraulic ram machinery includes a feed hopper 31 , into which the blended mix of material may be inserted, and is injected with some water from the liquid tank 32 , the mix being delivered from the hopper by way of an auger conveyor 33 , to a blender mixer 34 , as noted. At this location, the mix is completely blended, and then in dosages delivered to the compression chamber 35 where the hydraulic ram exerts significant pressure, up to two thousand two hundred sixty five pounds per square inch (2265 psi), upon the mixture, to compress the material into a solid and uniform block, having the configuration designed from the mold provided within the compression chamber, to shape the style of block desired. At this point, when the hydraulic pressure is eased, the blocks are delivered along a conveyor 36 , where the blocks can be stacked upon skids, pallets, or the like, and then left to stand for drying and curing. Following this, the blocks can be either stored or shipped for usage.
[0062] During the delivery of the material to the hopper 31 , a laborer will generally be emptying bags of the pre-mixed powder containing material relating to the formulation as defined in Table II, which may be modified or varied with any of the other type of waste fly ash, such as that derived from sugar beet waste lime, of Table III, or have some of the sand provided therein, as analyzed in Table V.
[0063] In the formation of the blocks from the hydraulic or other pressure compressed blocks, the material will be formed similar in the manner as the pre-mix for the extruding process, including the delivery of the ground wood to the plant, for mixing, as previously explained. The material from the mixer, in the extruding process of FIG. 2 , will be left dry, and bagged, for delivery to the feed hopper 31 , of the Vermeer Block Press.
[0064] Generally, the same formula is used as in the extruding process, but in the high pressure press, other blends will also work because of the pressure involved, up to three thousand pounds per square inch (3000 psi), which is further effective in forming the desired block.
[0065] It is likely that a blend of the sugar beet waste lime could be employed in the hydraulic pressing process, with a blend of an approximately twenty five (25%) by weight of the sugar beet waste lime, and seventy five percent (75%) by weight of class C fly ash. The pre-mix is added to the feed hopper 31 , with a blender 34 , built into it. A twelve volt marine type pump delivers treated water to the mixture. This makes the press totally self contained and portable because the hydraulic press mounts directly upon the trailer frame. Once the hydraulic engine is turned on, the pre-mix is poured into the feed hopper, delivered to the blender; some moisture is added, generally in the amount to make a substantially viscous pre-mix. The press is then applied, after a batch of the materials is deposited into the mold, at the compression chamber, for immediately forming a hard block. A spray system may be used for adding the water at the blender/mixer, and the water tank assembly holds approximately one hundred gallons of water. The compression chamber, at the mold, may include a weighing device, to ensure that the proper amount of materials is added into the mold, before compression is initiated. The mold may also be constructed in a manner to provide the shape the block is desired, as for example, the mold may contain the semi circular protrusions, in order to form the tongues 2 and grooves 3 , and the end grooves 4 , within the finished block, when compressed.
[0066] In actual practice, the compressed blocks, formed by the hydraulic press of this invention, are achieved as follows. The dry pre-mixed product, that which has been bagged at the mixer 24 in the extruding process, may be packaged in either ninety pound (90 lbs) bags or two thousand three hundred and fifty pounds (2350 lbs.) super sacks. The contractor may have the product delivered to the job site, or have it collected at the mixing plant. Part of the contractor's equipment will require the usage of a large truck to haul the product, and to pull the block press 30 with it.
[0067] The first step the operator does is to check the fluid levels in the engine and hydraulic reverse tanks. Second, the engine is started, and warmed up. Third, the operator selects either the manual or automatic setting. The manual setting is used with the ninety pound (90 lbs.) bags, while the automatic setting is used with the super sacks. In either case, the powder is fed into the feed hopper 31 . From there, the material is fed into the blender by way of the auger 33 . It then falls by gravity into the open compression chamber, where the mold is provided. Water is blended with the powder as it passes down through the blender. The compression cylinder is activated, either manually by the operator, or by press controls. The pressure varies from three hundred to three thousand pounds per square inch (300 to 3000 psi), as explained. When the pressure reaches the operator pre-set level, a second hydraulic cylinder, built into the machine, and arranged at a right angle at the rear of the compression chamber activates, pushing the compressed block out of the side ramp, onto the conveyor. Now, both cylinders retract, thus opening the compression chamber for more product from the blender. The cycle repeats, and each new block is pushed from the processor further onto the conveyor or ramp, for stacking onto a skid, or the like.
[0068] Variations or modifications to the subject matter of this invention may occur to those skilled in the art upon reviewing the disclosure as provided herein. Such variations, if within the spirit of this development, are intended to be encompassed within the scope of the invention as described herein. The description of the preferred embodiment, and as shown in the drawings and schematics, is set forth for illustrative purposes only.
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A compressed building block formed of a pre-mix of fly ash, either of the Class C type, is combined with either ground or pulverized wood chips, or with fine sand, and a plasticizer, and accelerator, then moisturized, and lastly either extruded or compressed in a mold into the configuration of a block. The block lacks a binder, except Portland cement for select military applications. A mold retardant may be added to the mixture, to provide the formed block with further beneficial attributes. The blocks may be formed by a system for extruding such blocks from the formulation, or they may be formed by means of a hydraulic or other press and pressed into the configuration of the desired block, needed for the construction.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 10/643,269, filed Aug. 18, 2003, now U.S. Pat. No. 6,797,573 which is a divisional of U.S. patent application Ser. No. 10/177,228, filed Jun. 21, 2002 now U.S. Pat. No. 6,756,675.
TECHNICAL FIELD
The present invention relates in general to memory circuits, and more particularly, to dynamic random access memory cells and a method for forming the same.
BACKGROUND OF THE INVENTION
Random access memory (“RAM”) cell densities have increased dramatically with each generation of new designs and have served as one of the principal technology drivers for ultra large scale integration (“ULSI”) in integrated circuit (“IC”) manufacturing. However, in order to accommodate continuing consumer demand for integrated circuits that perform the same or additional functions and yet have a reduced size as compared with available circuits, circuit designers continually search for ways to reduce the size of the memory arrays within these circuits without sacrificing array performance.
With respect to memory ICs, the area required for each memory cell in a memory array partially determines the capacity of a memory IC. This area is a function of the number of elements in each memory cell and the size of each of the elements. For example, FIG. 1 illustrates an array 100 of memory cells 110 for a conventional dynamic random access memory (DRAM) device. Memory cells 110 such as these are typically formed in adjacent pairs, where each pair is formed in a common active region 120 and share a common source/drain region that is connected to a respective digit line via a digit line contact 124 . The area of the memory cells 110 are said to be 8F 2 , where F represents a minimum feature size for photolithographically-defined features. For conventional 8F 2 memory cells, the dimension of the cell area is 2F×4F. The dimensions of a conventional 8F 2 memory cell are measured along a first axis from the center of a shared digit line contact 124 (½F), across a word line 128 that represents an access transistor (1F), a storage capacitor 132 (1F), an adjacent word line 136 (1F), and half of an isolation region 140 (½F) separating the active region 120 of an adjacent pair of memory cells (i.e., resulting in a total of 4F). The dimensions along a second perpendicular axis are half of an isolation region 150 on one side of the active region 120 (½F), the digit line contact 124 (1F), and half of another isolation region 154 on the other side of the active region 120 (½F) (i.e., resulting in a total of 2F).
In some state-of-the-art memory devices, the memory cells for megabit DRAM have cell areas approaching 6F 2 . Although this is approximately a 25% improvement in memory cell area relative to conventional 8F 2 memory cells, as previously described, a further reduction in memory cell size is still desirable. Therefore, there is a need for a compact memory cell structure and method for forming the same.
SUMMARY OF THE INVENTION
The present invention is directed to a semiconductor memory cell structure. The memory cell is formed on a surface of a substrate and includes an active region formed in the substrate, an epitaxial post formed on the surface of the substrate over the active region. The epitaxial post has at least one surface extending outwardly from the surface of the substrate and another surface opposite of the surface of the substrate. A vertical transistor is formed in the epitaxial post having a gate structure that is formed adjacent to at least a portion of all the outwardly extending surfaces of the epitaxial post. The memory cell further includes a memory cell capacitor formed on an exposed surface of the epitaxial post.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified top plan view of conventional memory cells.
FIG. 2A is a simplified top plan view of memory cells according to an embodiment of the present invention, and FIG. 2B is a simplified cross-sectional view of a pair of memory cells according to the embodiment shown in FIG. 2 A.
FIG. 3 is a simplified cross-sectional view of a semiconductor substrate that can be processed to form the memory cell of FIG. 2 , in accordance with an embodiment of the present invention.
FIG. 4 is a simplified cross-sectional view of the substrate of FIG. 3 at a later point in processing, in accordance with an embodiment of the present invention.
FIG. 5 is a simplified cross-sectional view of the substrate of FIG. 4 at a later point in processing, in accordance with an embodiment of the present invention.
FIG. 6 is a simplified cross-sectional view of the substrate of FIG. 5 at a later point in processing, in accordance with an embodiment of the present invention.
FIG. 7 is a simplified cross-sectional view of the substrate of FIG. 6 at a later point in processing, in accordance with an embodiment of the present invention.
FIG. 8 is a simplified cross-sectional view of the substrate of FIG. 7 at a later point in processing, in accordance with an embodiment of the present invention.
FIG. 9 is a simplified cross-sectional view of the structure of FIG. 2B at a later point in processing, in accordance with an embodiment of the present invention.
FIG. 10 is a simplified cross-sectional view of a pair of memory cell according to an alternative embodiment.
FIG. 11 is a functional block diagram of a memory circuit that includes memory cells according to an embodiment of the present invention.
FIG. 12 is a functional block diagram of a computer system including a memory device according to the embodiment shown in FIG. 11 .
As is conventional in the field of integrated circuit representation, the lateral sizes and thicknesses of the various layers are not drawn to scale, and portions of the various layers may have been arbitrarily enlarged or reduced to improve drawing legibility.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2A is a top plan view of an array of memory cells 200 according to an embodiment of the present invention. As shown in FIG. 2A , capacitors have not been illustrated in order to avoid unnecessarily obscuring the other structures of the memory cell 200 . The dimensions of the cell 200 are 4F 2 . That is, the cell 200 measures 2F along a first axis, starting with half of a digit line contact (½F), and extending over an epitaxial post on which a capacitor is formed (1F) and half of an isolation region (½F). Along a second perpendicular axis, the cell 200 measures 2F, starting with half of an isolation region (½F), and extending over the digit line contact (1F), and half of another isolation region (½F). FIG. 2B is a simplified cross-sectional view of the memory cell 200 ( FIG. 2A ) along A—A at a stage of processing. A more detailed description of the memory cell 200 will be provided with respect to FIGS. 3 through 10 , which illustrate the memory cell 200 at various stages of processing.
FIG. 3 is a simplified cross-sectional view of the memory cell 200 ( FIG. 2 ) at a stage of processing. Formed in a p-type substrate 204 is an n-type active region 206 in which a pair of memory cells 200 are formed. The active region 206 is isolated from adjacent active regions by isolation regions 202 . The active region 206 and the isolation regions 202 can be formed using conventional methods, for example, conventional masking, deposition, implant and drive-in processes. Following the formation of the isolation regions 202 and the active region 206 , a layer of insulating material is deposited onto the substrate 204 , masked and etched to form sacrificial structures 208 a-c on the substrate 204 . The insulating material from which the sacrificial structures 208 a-c are formed is silicon nitride, or alternatively, as will be explained in more detail below, other insulating material to which subsequent etch processes are selective.
FIG. 4 is a simplified cross-sectional view of the structure shown in FIG. 3 at a later point in processing, in accordance with an embodiment of the present invention. An insulating material is deposited over the substrate 204 and the sacrificial structures 208 a-c and subsequently etched back using an anisotropic etch process. Suitable etch processes are known in the art. Sidewalls 210 a-c , 212 a-c are formed as a result of the deposition and etch back processes. The insulating layer can be formed from a silicon-oxide material, and the etch back process should be selective to the silicon nitride of the sacrificial structures 208 a-c . A p-type epitaxial layer is formed on the exposed regions of the substrate 204 , and etched to selectively form epitaxial “posts” 220 , 222 within the trench region between the sacrificial nitride structures 208 a , 208 b , and 208 b , 208 c , respectively. As will be described in more detail below, the epitaxial posts 220 , 222 represent the material in which vertical access transistors (i.e., word lines) will be formed and to which memory cell capacitors are electrically coupled.
FIG. 5 is a simplified cross-sectional view of the structure shown in FIG. 4 at a later point in processing, in accordance with an embodiment of the present invention. An etch process selective to the nitride sacrificial structures 208 a-c and the epitaxial posts 220 , 222 is performed to remove the oxide sidewalls 210 a-c , 212 a-c . Gate oxide 230 is then formed over the epitaxial posts 220 , 222 and the exposed regions of the substrate 204 . The material of the sacrificial structures 208 a-c is such that oxide does not form thereon during the formation of the gate oxide 230 .
FIG. 6 is a simplified cross-sectional view of the structure shown in FIG. 5 at a later point in processing, in accordance with an embodiment of the present invention. A polysilicon layer is formed over the structure of FIG. 5 followed by a masking and etch process to selectively remove portions of the polysilicon layer. An anisotropic etch back process is then performed to remove additional portions of polysilicon layer in order to form gates 240 , 242 of vertical transistors 250 , 252 , respectively. The etch back process recesses the gates 240 , 242 to below the height of the epitaxial posts 220 , 222 , respectively. Although shown in cross-section in FIG. 6 , the gates 240 , 242 surround the respective posts 220 , 222 . This is apparent from FIG. 2A , which illustrates that the gate 242 is part of a continuous polysilicon wordline that is formed around each of the epitaxial posts associated with the memory cells of that row.
FIG. 7 is a simplified cross-sectional view of the structure shown in FIG. 6 at a later point in processing, in accordance with an embodiment of the present invention. An insulating layer is formed over the structure shown in FIG. 6 and subsequently etched back to form a relatively planar surface. Although a conventional chemical-mechanical polishing process can be used for the etch back step, it will be appreciated that other suitable etch back processes may be used as well. The etch back process results in the formation of insulating spacers 256 to isolate the gates 240 , 242 of the vertical transistors 250 , 252 . The insulating layer 258 , and consequently, the insulating spacers 256 , can be formed from a silicon oxide material, or other material, that is selective to a silicon nitride etch process.
FIG. 8 is a simplified cross-sectional view of the structure shown in FIG. 7 at a later point in processing, in accordance with an embodiment of the present invention. An etch process is used to remove the silicon nitride sacrificial structures 208 a-c to leave the epitaxial posts 220 , 222 , the vertical transistors 250 , 252 , and the insulating spacers 256 . An insulating material is then deposited over the remaining structure and anisotropically etched back to form sidewalls 260 that isolate the gates 240 , 242 of the vertical transistors 250 , 252 , respectively. As shown in FIG. 2B , a dielectric interlayer 264 is subsequently deposited over the existing structure and etched back to form a planar surface on which digit lines and storage capacitors can be formed. Still with reference to FIG. 2B , a via 270 is formed through the dielectric interlayer 246 to expose a portion the active region 206 . A conductive material 272 is subsequently deposited over the structure and in the via 270 to electrically contact the active region 206 . The conductive material 272 is masked and etched to form a digit line contact.
FIG. 9 is a simplified cross-sectional view of the structure shown in FIG. 2B at a later point in processing, in accordance with an embodiment of the present invention. A second dielectric interlayer 274 is deposited over the structure, and using conventional methods, container shaped memory cell capacitors 280 are formed in the second dielectric interlayer 274 and have a first capacitor plate 282 electrically coupled to a respective epitaxial post 220 , 222 . The first capacitor plate 282 can be formed from a highly doped polysilicon material, however, it will be appreciated that other suitable materials may be used as well. Following the formation of the first capacitor plates 282 of the memory cell capacitors 280 , dopants from the highly doped polysilicon layer are diffused into the respective epitaxial post 220 , 222 by heating the substrate 204 . As a result, lightly doped conductive regions 284 are created in the epitaxial posts 220 , 222 in a region adjacent the insulating spacers 256 . The lightly doped conductive regions 284 provide a conductive path between a memory cell capacitor 280 and the respective gate 240 , 242 of the vertical transistors 250 , 252 . Thus, when a vertical transistor is activated, the memory cell capacitor 280 can be electrically coupled to the active region 206 .
Although embodiments of the present invention have been described as including container shaped memory cell capacitors 280 , it will be appreciated that alternative capacitor structures can also be used as well without departing from the scope of the present invention. For example, conventional stacked capacitor structures electrically coupled to the epitaxial posts 220 , 222 could be used in an alternative embodiment of the present invention. Alternatively, capacitors having a first capacitor plate with multiple polysilicon layers, that is, a “finned” capacitor, could also be used. Moreover, other modifications can be made to the memory cell capacitors 280 as well and still remain within the scope of the present invention. An example of such a modification includes forming memory cell capacitors 280 having a rough surface such as a hemispherical silicon grain (HSG) layer (not shown). Consequently, the present invention is not limited to the specific embodiments described herein.
FIG. 10 illustrates a pair of memory cells 1000 according to an alternative embodiment of the present invention. Whereas memory cells 200 ( FIG. 9 ) includes a digit line contact formed from a conductive material 272 , the memory cell 1000 includes a buried digit line 1006 . Formation of the buried digit line 1006 is well known in the art and can be formed using conventional processing methods.
It will be appreciated that the description provided herein is sufficient to enable those of ordinary skill in the art to practice the invention. Selecting specific process parameters, including temperature, doping levels, thicknesses, and the like, are well within the understanding of those ordinarily skilled in the art. Particular details such as these have been omitted from herein in order to avoid unnecessarily obscuring the present invention. It will be further appreciated that additional processing steps can be performed in fabricating the memory cells 200 without departing from the scope of the present invention. For example, in forming the isolation regions 202 , an implant process can be performed to create a junction region below the isolation region 202 to minimize leakage currents between adjacent active regions. Another example of such a modification is performing an implant step prior to deposition of the conductive material 272 to create a highly doped region in the active region 206 to promote conductivity to the digit line contact.
FIG. 11 is a functional block diagram of one embodiment of a memory circuit 60 , which includes memory banks 62 a and 62 b . These memory banks each incorporate a memory array according to an embodiment of the present invention. In one embodiment, the memory circuit 60 is a synchronous DRAM (SDRAM), although it may be another type of memory in other embodiments.
The memory circuit 60 includes an address register 64 , which receives an address from an ADDRESS bus. A control logic circuit 66 receives a clock (CLK) signal receives clock enable (CKE), chip select (CS), row address strobe (RAS), column address strobe (CAS), and write enable (WE) signals from the COMMAND bus, and communicates with the other circuits of the memory device 60 . A row-address multiplexer 68 receives the address signal from the address register 64 and provides the row address to the row-address latch-and-decode circuits 70 a and 70 b for the memory bank 62 a or the memory bank 62 b , respectively. During read and write cycles, the row-address latch-and-decode circuits 70 a and 70 b activate the word lines of the addressed rows of memory cells in the memory banks 62 a and 62 b , respectively. Read/write circuits 72 a and 72 b read data from the addressed memory cells in the memory banks 62 a and 62 b , respectively, during a read cycle, and write data to the addressed memory cells during a write cycle. A column-address latch-and-decode circuit 74 receives the address from the address register 64 and provides the column address of the selected memory cells to the read/write circuits 72 a and 72 b . For clarity, the address register 64 , the row-address multiplexer 68 , the row-address latch-and-decode circuits 70 a and 70 b , and the column-address latch-and-decode circuit 74 can be collectively referred to as an address decoder.
A data input/output (I/O) circuit 76 includes a plurality of input buffers 78 . During a write cycle, the buffers 78 receive and store data from the DATA bus, and the read/write circuits 72 a and 72 b provide the stored data to the memory banks 62 a and 62 b , respectively. The data I/O circuit 76 also includes a plurality of output drivers 80 . During a read cycle, the read/write circuits 72 a and 72 b provide data from the memory banks 62 a and 62 b , respectively, to the drivers 80 , which in turn provide this data to the DATA bus.
A refresh counter 82 stores the address of the row of memory cells to be refreshed either during a conventional auto-refresh mode or self-refresh mode. After the row is refreshed, a refresh controller 84 updates the address in the refresh counter 82 , typically by either incrementing or decrementing, the contents of the refresh counter 82 by one. Although shown separately, the refresh controller 84 may be part of the control logic 66 in other embodiments of the memory device 60 . The memory device 60 may also include an optional charge pump 86 , which steps up the power-supply voltage V DD to a voltage V DDP . In one embodiment, the pump 86 generates V DDP approximately 1-1.5 V higher than V DD . The memory circuit 60 may also use V DDP to conventionally overdrive selected internal transistors.
FIG. 12 is a block diagram of an electronic system 1212 , such as a computer system, that incorporates the memory circuit 60 of FIG. 11 . The system 1212 also includes computer circuitry 1214 for performing computer functions, such as executing software to perform desired calculations and tasks. The circuitry 1214 typically includes a processor 1216 and the memory circuit 60 , which is coupled to the processor 1216 . One or more input devices 1218 , such as a keyboard or a mouse, are coupled to the computer circuitry 1214 and allow an operator (not shown) to manually input data thereto. One or more output devices 1220 are coupled to the computer circuitry 1214 to provide to the operator data generated by the computer circuitry 1214 . Examples of such output devices 1220 include a printer and a video display unit. One or more data-storage devices 1222 are coupled to the computer circuitry 1214 to store data on or retrieve data from external storage media (not shown). Examples of the storage devices 1222 and the corresponding storage media include drives that accept hard and floppy disks, tape cassettes, and compact disk read-only memories (CD-ROMs). Typically, the computer circuitry 1214 includes address data and command buses and a clock line that are respectively coupled to the ADDRESS, DATA, and COMMAND buses, and the CLK line of the memory device 60 .
From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. For example, the memory cell 200 has been illustrated as having epitaxial posts with a rectangular or quadrilateral cross-sectional area. However, the epitaxial posts can be formed having a generally circular cross-sectional area or a generally polygonal cross-sectional area as well. Accordingly, the invention is not limited except as by the appended claims.
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A semiconductor memory cell structure and method for forming the same. The memory cell is formed on a surface of a substrate and includes an active region formed in the substrate, an epitaxial post formed on the surface of the substrate over the active region. The epitaxial post has at least one surface extending outwardly from the surface of the substrate and another surface opposite of the surface of the substrate. A gate structure is formed adjacent to at least a portion of all the outwardly extending surfaces of the epitaxial post, and a capacitor formed on an exposed surface of the epitaxial post.
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PRIORITY
This application claims priority to an application filed in the Korean Industrial Property Office on Jan. 13, 2006 and assigned Serial No. 2006-004146, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and a method for transmitting/receiving a signal in a communication system, and more particularly to an apparatus and a method for transmitting/receiving a signal by using an Affine Permutation Matrix (APM)-Low Density Parity Check (LDPC) code, which is an improved structured LDPC code, in a communication system.
2. Description of the Related Art
Next-generation communication systems have evolved into the form of a packet service communication system for transmitting burst packet data to a plurality of Mobile Stations (MS), and the packet service communication system has been designed to be suitable for mass data transmission. Further, next-generation communication systems are actively considering using an LDPC code, together with a turbo code. The LDPC code is known to have an excellent performance gain at high-speed data transmission, and has an advantage in that it can enhance data transmission reliability by effectively correcting errors due to noise occurring in a transmission channel.
Reference will now be made to FIG. 1 , which illustrates the structure of a signal transmission apparatus in a conventional communication system using an LDPC code.
Referring to FIG. 1 , the signal transmission apparatus includes an encoder 111 , a modulator 113 and a transmitter 115 . First, if an information vector s to be transmitted occurs in the signal transmission apparatus, the information vector s is delivered to the encoder 111 . The encoder 111 generates a codeword vector c , that is, a non-binary LDPC codeword, by encoding the information vector s in a predetermined encoding scheme, and then outputs the generated codeword vector c to the modulator 113 . Here, the predetermined encoding scheme corresponds to a non-binary LDPC encoding scheme. The modulator 113 generates a modulation vector m by modulating the codeword vector c in a predetermined modulation scheme, and then outputs the generated modulation vector m to the transmitter 115 . The transmitter 115 inputs therein the modulation vector m output from the modulator 113 , executes transmission signal processing for the input modulation vector m, and then transmits the processed modulation vector m to a signal reception apparatus through an antenna.
Next, reference will be made to FIG. 2 , which illustrates the structure of a signal reception apparatus in a conventional communication system using an LDPC code.
Referring to FIG. 2 , the signal reception apparatus includes a receiver 211 , a demodulator 213 and a decoder 215 . First, a signal transmitted by a signal transmission apparatus, such as shown in FIG. 1 , is received through an antenna of the signal reception apparatus, and the received signal is delivered to the receiver 211 . The receiver 211 executes reception signal processing for the received signal to thereby generate a reception vector r , and then outputs the processed and generated reception vector r to the demodulator 213 . The demodulator 213 inputs therein the reception vector r output from the receiver 211 , generates a demodulation vector x by demodulating the input reception vector r in a demodulation scheme corresponding to a modulation scheme applied to a modulator of the signal transmission apparatus (that is, the modulator 113 ), and then outputs the generated demodulation vector x to the decoder 215 . The decoder 215 inputs therein the demodulation vector x output from the demodulator 213 , decodes the input demodulation vector x in a decoding scheme corresponding to an encoding scheme applied to an encoder of the signal transmission apparatus (that is, the encoder 111 ), and then outputs the decoded demodulation vector x into a finally restored information vector ŝ .
Meanwhile, the LDPC code has performance approximating a channel capacity limit presented in Shannon's channel coding theorem. In order to generate an LDPC code having such good performance, a cycle and a density distribution on the Tanner graph of an LDPC code must be considered, and particularly consideration must be given to maximizing a girth on the Tanner graph. Here, “girth” denotes a minimum cycle length on the Tanner graph of a parity check matrix of the LDPC code. The reason why consideration must be given to maximizing the girth on the Tanner graph is that a cycle on the Tanner graph must be generally longer in order not to cause performance deterioration, such as an error floor, which occurs when there are many comparatively short-length cycles (for example, cycles having a length of 4), on the Tanner graph.
Thus, research is being conducted to provide schemes for generating a parity check matrix in such a manner so as not to produce short-length cycles on the Tanner graph, two typical ones of which are Scheme 1, in which short-length cycles are removed from a given random LDPC code, and Scheme 2, in which an LDPC code with no short-length cycle is algebraically generated. Scheme 2 is mainly used from these two schemes because the memory capacity required for storing parity check matrixes is large, and it is difficult to implement efficient LDPC encoding in the case of Scheme 1. Here, an LDPC code generated by applying Scheme 2 is called a structured LDPC code, and reference will now be made to a parity check matrix of a general structured LDPC code, with reference to FIG. 3 .
As illustrated in FIG. 3 , the parity check matrix of a general structured LPDC code has a structure in which the overall parity check matrix is divided into a plurality of blocks, and a permutation matrix corresponds to each block. Here, it is assumed that the permutation matrix has a size of L×L. As seen from FIG. 3 , the parity check matrix of the structured LDPC code is divided into (p×q) number of blocks, and a permutation matrix corresponds to each block. In FIG. 3 , P a pq indicates a permutation matrix located at an intersection point of a pth block row and a qth block column among the plurality of blocks. Here, the superscript “a pq ” is 0≦a pq ≦1 or a pq =∞.
Further, the permutation matrix corresponding to each block is referred to as a “block matrix”. In the case where the respective block matrixes within the parity check matrix are selected to only an identity matrix, if the location of a non-zero element in the first row of each block matrix is determined, then the locations of the remaining non-zero elements, that is, (L−1) number of elements, are determined. Thus, the memory capacity required for storing information on the overall parity check matrix is reduced to 1/L, as compared with that in the case where the locations of non-zero elements irregularly distributed in each block matrix are selected, that is, in the case where an LDPC code is generated by applying Scheme 1.
It can be noted from the foregoing that the structured LDPC code has improved performance by considering not only the memory capacity required for storing parity check matrix information, but also efficient encoding. However, the structured LDPC code which is currently proposed in the art has a drawback in that its cycle is affected by a parent matrix thereof, and an upper limit is restricted by several numerals related to its parent matrix irrespective of which code length and permutation matrixes are selected.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made to solve at least the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide an apparatus and a method for transmitting/receiving a signal in a communication system.
A further object of the present invention is to provide an apparatus and a method for transmitting/receiving a signal using a structured LDPC code in a communication system.
A further object of the present invention is to provide an apparatus and a method for transmitting/receiving a signal using an APM-LDPC code, which is an improved structured LDPC code, in a communication system.
In order to accomplish these objects, the present invention generates an APM-LDPC codeword by encoding an information vector in an APM-LDPC encoding scheme, which is a preset structured LDPC encoding scheme, thereby making it possible to generate an LDPC code in the form of maximizing a girth while minimizing complexity.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a block diagram illustrating the structure of a signal transmission apparatus in a conventional communication system using an LDPC code;
FIG. 2 is a block diagram illustrating the structure of a signal reception apparatus in a conventional communication system using an LDPC code;
FIG. 3 is a view illustrating a parity check matrix of a general structured LDPC code;
FIG. 4 is a view illustrating connected block cycles on the Tanner graph in accordance with the present invention; and
FIG. 5 is a view illustrating function chains of two different block cycles connected with each other by p number of blocks on the Tanner graph in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the similar components are designated by similar reference numerals although they are illustrated in different drawings. Also, in the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may obscure the subject matter of the present invention. Further, it should be noted that only parts essential for understanding the operations according to the present invention will be described and a description of parts other than the essential parts will be omitted in order not to obscure the present invention.
The present invention provides an apparatus and a method for transmitting/receiving a signal in a communication system. Further, the present invention provides an apparatus and a method for transmitting/receiving a signal using an Affine Permutation Matrix (“APM”)-Low Density Parity Check (“LDPC”) code, which is an improved structured LDPC code, in a communication system. Further, although separately described and illustrated herein, it is clear that a procedure of transmitting a signal using the APM-LDPC code of the present invention may be applied to a signal transmission apparatus of a communication system, which has a structure as illustrated in FIG. 1 , and a procedure of receiving a signal by using the APM-LDPC code of the present invention may be applied to a signal reception apparatus of a communication system, which has a structure as illustrated in FIG. 2 .
First, assume that Z L ={0, 1, . . . , L−1} is an integer ring of modulo L, and Z* L ={iεZ L |gcd(i,L)=1}. Further, for aεZ* L and bεZ L , an Affine function ƒ (a,b) on Z L , which is defined by ƒ (a,b) (x)=ax+b, can be considered. The Affine function ƒ (a,b) can also be extended to an L×L permutation matrix P ƒ (a,b) whose (i, j)th element is defined as the following Equation (1):
[
P
f
(
a
,
b
)
]
=
{
1
if
j
=
f
(
a
,
b
)
(
i
)
0
otherwise
(
1
)
Hereinafter, for the convenience of explanation, the permutation matrix P ƒ (a,b) is referred to as an “Affine permutation matrix”, and an L×L zero matrix, a set of Affine functions on Z L and a set of L×L Affine permutation matrixes, including the L×L zero matrix, will be designated by P ∞ , A L and P L , respectively.
Consider an LDPC code C whose length is nL and which has a parity check matrix H as given in the following Equation (2):
H
=
[
P
f
11
p
f
12
⋯
P
f
1
n
P
f
21
P
f
22
⋯
P
f
2
n
⋮
⋮
⋯
⋮
P
f
m
1
P
f
m
2
⋯
P
f
mn
]
(
2
)
In Equation (2), ƒ ij has a value of an Affine function related to (a ij ,b ij )εZ* L ×Z L for i and j or a value of ∞.
A structured LDPC code generated by applying the parity check matrix H including Affine permutation matrixes is referred to as an “APM-LDPC code”. Here, if the exponent a ij of the Affine permutation matrix is equal to 1, p ƒ ij denotes a circulant permutation matrix. Further, an APM-LDPC code satisfying a ij =1 for all i and j is called a Quasi-Cyclic (QC) LDPC code. Further, for a fixed (a j , b j ), the locations of all non-zero elements P ƒ ij , for example, the locations of elements having a value of 1, are uniquely determined. Thus, the memory capacity required for storing the parity check matrix of the APM-LDPC code is reduced to 1/L, as compared with that of a randomly-configured LDPC code.
For the purpose of this discussion, several terms are defined below:
(1) Parent Matrix
An m×n binary matrix M(H) can be generated by substituting zero matrixes and Affine permutation matrixes, included in a parity check matrix as expressed by Equation (2), with 0 and 1, respectively, and the matrix generated in this way is referred to as a “parent matrix”.
(2) Function Matrix
A function matrix F(H) of the above-mentioned parity check matrix H may be defined by the following Equation (3):
F ( H ) = [ f 11 f 12 ⋯ f 1 n f 21 f 22 ⋯ f 2 n ⋮ ⋮ ⋯ ⋮ f m 1 f m 2 ⋯ f mn ] ( 3 )
(3) Function Extension
The parity check matrix H is generated by extending an m×n function matrix to an m×n matrix defined on P L , and such an extension procedure, expressed by H=E L (F), is referred to as a “function extension” procedure.
(4) Block Cycle and Overlap
If a cycle with a length of 2l exists on the Tanner graph of the parent matrix M(H), then such a cycle is referred to as a “2l-sized block cycle”. Further, if one Affine permutation matrix belongs to two or more block cycles, then this is referred to as an “overlap between block cycles”.
(5) Function Chain
If a 2l-sized block cycle corresponding to 2l number of Affine permutation matrixes P ƒ 1 , P ƒ 2 , . . . , P ƒ 2l exists in the parity check matrix H within the parent matrix M(H), then (ƒ 1 , . . . , ƒ 2l ) is referred to as a function chain. Further, for 1≦i≦2l, P ƒ i and P ƒ i+1 are located in the same row or column block of the parity check matrix H, and P ƒ i and P ƒ i+2 are located in different row and column blocks of the parity check matrix H. Here, P ƒ 2l+1 =P ƒ 1 , and P ƒ 2l+2 =P ƒ 2 .
(6) Connected Block Cycle
Reference will now be made to FIG. 4 , which illustrates connected block cycles on the Tanner graph according to the present invention.
As illustrated in FIG. 4 , when two different block cycles are connected with each other by p number of edges, which are connected one after another, on the Tanner graph of an m×n binary matrix M(H), it can be said that they are connected with each other by p number of blocks corresponding to the connected edges. In particular, if p=0, the block cycles share one bit or check node within the m×n binary matrix M(H), which is referred to as “directly connected”.
(7) Composition of Functions
Given ƒ j , 1≦i≦s, a composition sequence can be defined by the following Equation (4):
⊙
s
i
=
1
f
i
(
x
)
=
△
f
s
·
f
s
-
1
·
…
·
f
1
(
x
)
(
4
)
In Equation (4), “∘” is a symbol indicating composition of functions. Here, ƒ∘g(x)=ƒ(g(x)). If ƒ i =ƒ for all i, then this is abbreviated to ƒ s (x), and ƒ 1 (x) is an inverse function of ƒ(x). For the convenience of explanation, an operation as given in the following Equation (5) is now defined:
⊗ s i = j f i ( x ) = △ f s ( - 1 ) s - i + 1 · … · f j + 2 - 1 · f j + 1 … f ( 5 )
(8) Characteristic Function of Function Chain
For a given function chain (ƒ 1 , . . . ,ƒ 2l ), its characteristic function z(x) is defined as
⊗ i = 1 2 l f i ( x ) ,
and if all ƒ i (x) are Affine functions, then the characteristic function z(x) is also an Affine function.
Next, reference will be made to cycle properties of the APM-LDPC code.
Owing to the inherent structure of the APM-LDPC code's parity check matrix, the cycle properties of the APM-LDPC code can be algebraically analyzed with ease. Now, an upper limit for a girth of the APM-LDPC code will be detected, and the detected upper limit will be described in comparison with the upper limit of a QC-LDPC code. Here, the girth indicates a minimum cycle length on the Tanner graph of a parity check matrix.
First, Theorem 1, as will be described below, presents the necessary and sufficient condition under which the APM-LDPC code has a cycle.
Theorem 1
It is assumed that (ƒ 1 , . . . , ƒ 2l ) is a function chain which corresponds to a 2l-sized block cycle of an APM-LDPC code, and has a parity check matrix H and a characteristic function z(x). Further, let r be a minimum positive integer satisfying the following Equation (6):
z r ( x 0 )≡ x 0 mod L (6)
In Equation (6), x 0 εZ L , and thus the block cycle corresponds to a cycle which has a length of 2lr on the Tanner graph of the APM-LDPC code.
Further, when z(x)=ax+b for (a,b)εZ* L ×Z L , z r (x)=a r x+(a r−1 + . . . +a+1)b. Thus, a solution x 0 satisfying z r (x 0 )=x 0 exists, which is identical to gcd(a r −1,L)|(a r−1 +a r−2 + . . . +a+1)b. When a=1, Equation (6) is under the same condition as rb≡0 mod L. Further, since the QC-LDPC code is an LDPC code having an Affine function in the form of ƒ ij (x)=x+b ij , Theorem 2 can be defined as follows:
Theorem 2
It is assumed that (ƒ 1 , . . . , ƒ 2l ) is a function chain which corresponds to a 2l-sized block cycles of an QC-LDPC code and has ƒ i (x)=x+b i , and that r is a minimum positive integer satisfying the following Equation (7):
r
∑
i
=
1
2
l
(
-
1
)
i
b
i
≡
0
mod
L
(
7
)
Thus, the block cycle is a cycle which has a length of 2lr on the Tanner graph of the QC-LDPC code.
Using Theorems 1 and 2, cycles of the APM-LDPC code and the QC-LDPC code can be expressed by a simple equation, which makes it possible to remove short-length cycles on the Tanner graph. This will be described below.
First of all, it is assumed that matrixes, as given in the following Equation (8), exist:
F
1
=
[
2
x
+
1
3
x
5
x
4
x
]
,
F
2
=
[
2
x
+
3
3
x
+
1
4
x
+
5
x
+
1
]
,
F
3
=
[
x
3
x
5
x
+
1
3
x
]
(
8
)
In Equation (8), F 1 and F 2 are defined in A 7 , and F 3 is defined in A 8 . Further, for the matrixes, each function chain corresponding to a 4-sized block cycle can be expressed by the following Equation (9):
F 1 :(2x+1,3x,4x,5x), F 2 :(2x+3,3x+1,x+1,4x+5), F 3 : (x,3x,3x,5x+1) (9)
Thus, each characteristic function corresponding to each of the function chains can be expressed by the following Equation (10):
z 1 ( x )= x+ 6 ,z 2 ( x )=6 x+ 1 ,z 3 ( x )=5 x+ 1 (10)
In the case of z 1 (x) in Equation (10), the minimum positive integer satisfying Equation (6) is r=7, which indicates a cycle having a size of 4×7=28 on the Tanner graph H 1 =E 7 (F 1 ). Further, in the case of z 2 (x) in Equation (10), the minimum positive integer satisfying Equation (6) for x=4 is r=1, and for the remaining x, the minimum positive integer satisfying Equation (6) is r=2, which indicates that one cycle with a size of 4 and three cycles with a size of 8 exist on the Tanner graph H 2 =E 7 (F 2 ). Further, in the case z 3 (x) in Equation (10), the minimum positive integer satisfying Equation (6) is r=8, which indicates that one cycle with a size of 32 exists on the Tanner graph H 3 =E 8 (F 3 ).
In addition, although the cycle structure of the QC-LDPC code is greatly affected by the parent matrix, the APM-LDPC code is less affected by the parent matrix when compared with the QC-LDPC code, which can be demonstrated using Theorem 3.
Theorem 3
It is assumed that p number of overlaps exist between a 2l-sized block cycle and a 2k-sized block cycle in an APM-LDPC code defined by an L×L Affine permutation matrix, and that function chains as given in the following Equation (11) correspond to the block cycles, respectively:
function chain 1: (ƒ 1 ,ƒ 2 , . . . ,ƒ p ,ƒ p+1 ,ƒ 2l )
function chain 2: (g 1 ,g 2 , . . . ,g p ,g p+1 , . . . ,g 2k ) (11)
In Equation (11), ƒ i =g j for i=1, 2, . . . , p. Further, it is assumed that function chains 1 and 2 have characteristic functions of z 1 (x)=a 1 x+b 1 and z 2 (x)=a 2 x+b 2 , respectively. Further, if it is assumed that r is a minimum positive integer satisfying r(b 1 −b 2 +a 1 b 2 −a 2 b 1 )≡0 mod L, the minimum cycle of the APM-LDPC code is 2r(2l+2k−p).
Irrespective of the size of the Affine permutation matrix, cycles caused by the overlaps between the block cycles may exist in the Tanner graph of the APM-LDPC code. Thus, if it is possible to remove as many block cycle overlaps as possible from a parent matrix, many short-length cycles in a corresponding parity check matrix can be avoided. However, even if there is no overlap between block cycles, the upper limit of a girth is restricted by numerals related to two connected block cycles.
Theorem 4
FIG. 5 illustrates function chains of two different block cycles connected with each other by p number of blocks on the Tanner graph according to the present invention.
As illustrated in FIG. 5 , it is assumed that two different block cycles, whose sizes are 2l and 2k, respectively, are connected with each other by p number of blocks in an APM-LDPC code. Here, respective function chains corresponding to the block cycles are given as represented by the following Equation (12):
function chain 1: (ƒ 1 ,ƒ 2 , . . . ,ƒ 2 l)
function chain 2: (g 1 ,g 2 , . . . ,g 2 k) (12)
Further, it is assumed that the connected blocks are (P h 1 , P h 2 , . . . P h P ), z i (x)=a i x+b i is a characteristic function of function chain i,
⊙
i
=
1
p
h
i
(
-
1
)
i
(
x
)
=
a
3
x
+
b
3
and
⊙
i
=
1
2
k
g
i
(
-
1
)
i
+
p
(
x
)
=
a
4
x
+
b
4
.
Further, let r be a minimum positive integer satisfying the following Equation (13):
r ( a 3 b 1 ( a 4 −1)− b 4 ( a 1 −1)− b 3 ( a 1 −1)( a 4 −1))≡0 mod L , when p≧ 1
r ( b 1 −b 2 +a 1 b 2 −a 2 b 1 )≡0 mod L , when p= 0 (13)
In this case, a girth of the corresponding APM-LDPC code is 4r(l+k+p).
Theorem 5
If it is assumed that for a prime number L, two different block cycles, whose sizes are 2l and 2k, respectively, are connected with each other by p number of blocks in a parity check matrix of an APM-LDPC code defined by an L×L Affine permutation matrix, a girth of the APM-LDPC code is 4(l+k+p).
As described above, the present invention has an advantage in that it is possible to transmit/receive a signal using an APM-LDPC code. Further, the present invention makes it possible to generate an APM-LDPC code corresponding to an LDPC code which maximizes a girth while minimizing complexity, thereby providing an APM-LDPC code with superior performance.
While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
|
Disclosed is an apparatus and a method for transmitting/receiving a signal in a communication system, which generates an Affine Permutation Matrix-Low Density Parity Check (APM-LDPC) codeword by encoding an information vector in an APM-LDPC encoding scheme which is a preset structured LDPC encoding scheme, and detects the information vector by decoding the signal in a decoding scheme corresponding to the APM-LDPC encoding scheme, thereby making it possible to generate a Low Density Parity Check (LDPC) code in the form of maximizing a girth while minimizing complexity.
| 7
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to photographic apparatus including an instant of self-developing type camera and a film assemblage which interrelate with each other to control the thickness and/or shape of a layer of processing liquid to be spread between layers of an exposed film unit.
2. Description of the Prior Art
The invention is directed to certain improvements in the relationship between photographic film assemblages of the self-developing type and the cameras (or camera backs) with which they are adapted to be used. More specifically, the invention relates to a relationship between the two which allows for a greater spacial juxtapositioning between processing liquid spread control features on a film cassette and the liquid spreading and control structures in a camera.
As pointed up in U.S. Pat. No. 3,799,770, an important step in the processing of an exposed instant or self-developing type film unit is the spreading of a processing liquid between predetermined layers of the film unit to initiate the formation of a visible image therein via a diffusion transfer process. In order to obtain an optimum quality positive print, it is desirable that the processing liquid be spread such that it covers the entire photoexposed area of the film unit in a thin layer of predetermined uniform thickness.
A typical film unit includes a photosensitive element, an image-receiving element which may be superposed on the photosensitive element subsequent to exposure or may be transparent and predisposed on the photosensitive element such that exposure may be made through the image-receiving element, and a rupturable pod or container of processing liquid located at one end of the two elements.
In a typical self-developing photographic system, the film units are arranged in stacked relation within a film cassette which is adapted to be inserted into the receiving chamber of an appropriate camera to locate an endmost film unit in the stack in position for exposure.
Subsequent to exposure, the endmost film unit is extracted from the film cassette and is advanced, pod end first, between a pair of pressure-applying members mounted within the camera. The pressure-applying members exert a compressive force on the pod causing it to rupture and discharge the liquid between predetermined layers of the film unit, e.g., between the exposed photosensitive element and the superposed image-receiving element. Continued advancement of the film unit between the pressure-applying members results in the liquid being advanced along a liquid wave front toward the trailing end of the film unit such that it is progressively distributed over the photoexposed area of the film unit.
The uniformity of the liquid layer is, to a large degree, determined by the initial shape of the liquid wave front. In order to uniformly spread the processing composition over a substantially rectangular or square photoexposed area it is preferable that the wave front be disposed in a substantially straight line which extends outwardly to the lateral margins of the area and is oriented in a direction that is normal to the direction of film advancement between the pressure-applying members.
There are several factors which effect the initial shape of the wave front. One is a design of the pod and its rupture characteristics. Another relates to the viscosity and amount of liquid enclosed by the pod. The wave front shape is also influenced by the velocity at which the film unit is advanced through the pressure-applying members, the amount of compressive pressure exerted on the film unit, and the resistance to liquid flow at the interfaces between the liquid and the superposed film unit elements.
One of the most commonly observed spread shapes is a tongue shape wherein the wave front progresses more rapidly at the central portion of the photoexposed or image-forming area than out at the lateral margins. This condition may be caused by an uneven distribution of liquid upon initial discharge from the pod, i.e., more liquid being concentrated at the center of the film unit than out at its edges. In the subsequent spreading of the tongue-shaped wave front, it is possible that the corners of the image-forming area at the trailing end of the film unit will be coated with a layer of liquid of reduced depth or thickness, thus, possibly adversely affecting the film unit's sensitometry or not be coated at all.
In an instant type film unit of the "integral type", as shown in U.S. Pat. No. 4,693,963, the film unit is configured as including first and second superposed sheets, at least one of which comprises photosensitive constituents, whose lateral edges are permanently secured to each other by longitudinally extending rails. Because these sheets are bound at their lateral edges, the sheets tend to separate more in the center of the film unit than out at the lateral margins in response to the processing liquid being spread therebetween. Thus, there is more resistance to the flow of the processing liquid at the edges of the film unit vis-a-vis its center section. Upon initial discharge of the liquid from its pod, it assumes a rearwardly extending tongue shape rather than proceeding toward the trailing end of the film unit along a uniform wave front.
One method employed to compensate for a tongue-shaped wave front has been to provide excess liquid in the pod. Another method has been to equip the camera with spread control devices which serve to modify the shape of the liquid wave front during spreading.
The spread control devices are designed to apply a second compressive force to the central portion of the film unit in the path of the mass of liquid discharged from the pod by the pressure-applying members. This serves to retard the central portion of the wave front and cause a flow of liquid in a direction transverse to the direction of film advancement. In this manner, the wave front is modified such that it is substantially straight and is oriented in a direction substantially normal to the parallel sides of the rectangular or square image-forming area.
For examples of cameras which include processing liquid spread control means reference should be had to U.S. Pat. Nos. 3,241,468, 3,777,647 and 3,810,211. For examples of film assemblages which include film cassettes having processing liquid spread control features reference should be had to U.S. Pat. Nos. 3,779,770, 3,832,731, 4,104,669 and 4,226,519.
A major drawback with systems of the type shown and described in the patents listed above is that the control features located on the film cassette are formed on interior surfaces thereof and thus must be spaced relatively close to the pressure-applying means or spread rollers of the camera in order to be effective. This severely restricts the options available to a camera designer in the placement of the spread rollers relative to the film cassette. Further, if spreading of the processing liquid takes place substantially at the location where the film unit emerges from its cassette, then it is generally advisable that the film unit be maintained in a planar condition until processing of the image has been substantially completed. This is so as not to subject that layer of processing liquid to any external forces, such as may be caused by bending the film unit during its transport to a storage chamber or to the exterior of the camera.
SUMMARY OF THE INVENTION
The present invention relates to an instant or self-developing type camera and to a film assemblage specifically adapted for use therewith. The camera includes a film chamber having an apertured plate for properly locating the film assemblage in a focal plane of the camera. The film assemblage includes a film cassette having a generally parallelepiped configuration. Preferably, the film cassette is molded from any suitable material which is compatible with film units to be located therein. A forward wall of the film cassette includes a generally rectangularly shaped aperture therein through which an endmost film unit in a stack of film units located within the cassette may be photographically exposed. A bottom wall of the cassette has a processing liquid spread control means molded in an exterior surface thereof. A leading end wall of the cassette is formed with a laterally extending slot or egress which is dimensioned to permit the movement of a film unit therethrough; and a trailing end wall is configured with a slot for receiving a film unit advancing member of the camera which is adapted to engage a trailing end of the endmost film unit, subsequent to its exposure, prior to moving it to the exterior of the cassette via the egress.
The camera further includes a pair of shafts, at least one of which is motor driven, each of which includes on its opposite ends a section of increased diameter which define opposite pairs of superposed edge rollers. These rollers are adapted to engage opposite margins of the endmost film unit so as to continue its movement in a first direction into an arcuate passageway which functions to redirect the endmost film unit in a second direction into the bite of another set of laterally spaced pairs of edge rollers. The latter edge rollers continue the movement of the exposed endmost film unit between a pressure plate and the processing liquid spread control means on the film cassette and then into the bite of a pair of elongate rollers. The elongate rollers are adapted to be driven in a direction so as to rupture a container of processing liquid attached to a leading end of the endmost film unit and spread its contents between layers of the film unit to initiate the formation of a visible image therein while simultaneously advancing the film unit into a lighttight storage chamber. The film unit is adapted to stay in the storage chamber until its emerging is no longer susceptible to being adversely affected by being moved into the ambient light. Alternatively, the film unit may contain its own opacification system for preventing such exposure, in which case the storage chamber need not be lighttight or may be omitted and the film advanced directly to the exterior of the camera.
As the container of processing liquid is ruptured by the spread rollers, the emerging processing liquid forms a wave which travels in a direction toward the pressure plate as well as from the leading end of the film unit to its trailing end. The pressure plate is biased against one major surface of the endmost film unit so as to move an opposite major surface of the film unit into engagement with the processing liquid spread control means formed in the external surface of the film cassette's bottom wall. The constraint applied to opposite sides of the advancing film unit by the pressure plate and the processing liquid spread control means, at a point immediately in front of the advancing wave of processing liquid, acts to retard the wave's progress at intermediate portions of the wave, thus providing a wave front which is relatively linear and perpendicular to the direction of movement of the film unit through the spread rollers.
A side wall of the film cassette is formed with a tab or protrusion which is adapted to engage a portion of a movably mounted structure for supporting the spread rollers, which structure locates the spread rollers in the path of movement that a film unit would take during its movement from the film cassette to the storage chamber. The precise location of the tab relative to the film cassette's bottom or top wall, or its thickness, is chosen so as to insure that the gap or bite between the superposed spread rollers occupies a predetermined relation to the path of movement of the film unit at a location immediately prior to the latter's leading edge engaging one of the spread rollers. Thus, by judiciously selecting the location of the tab on the cassette's side wall, the aforementioned relationship between the gap and the path of travel can be altered thus effectively increasing or decreasing the angle at which the film unit enters the gap thereby changing the thickness of the layer of processing liquid to be spread by the rollers. For example, it the path of travel of the film unit into the bite between the spread rollers in generally perpendicular to a plane containing the axes of the spread rollers, then any deviation from such path will result in a thinner thickness of processing liquid being spread between elements or layers of the film unit. Conversely, if the angle of entry of the film unit is not perpendicular to said plane, than any relative movement between the two towards a perpendicular relationship will result in a thicker spread.
An object of the invention is to provide a camera of the instant type with means for urging an exposed film unit into engagement with a processing liquid spread control means located on an exterior surface of a film cassette as a processing liquid is being spread between layers of the film unit.
Another object of the invention is to provide a film cassette with means for locating a pair of camera mounted spread rollers having a gap therebetween relative to a path of travel to be taken by an exposed film unit of the instant type as it is moved into the gap thereby affecting the thickness of a layer of processing liquid to be spread between elements of the exposed film unit.
Still another object of the invention is to provide a photographic film assemblage with a film cassette having means in an external surface thereof for cooperating with structure in a camera for controlling the distribution of a quantity of processing liquid between layers of an exposed film unit of the instant type.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the structure possessing the construction, combination of elements and arrangements of parts which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:
FIG. 1 is a perspective view of an instant type folding camera which embodies the present invention;
FIG. 2 is a perspective view of the camera of FIG. 1 shown in its erected operative position;
FIG. 3 is an enlarged partial view of the camera taken generally along the line 3--3 in FIG. 1 with parts omitted for reasons of clarity;
FIG. 4 is an enlarged perspective view showing the relationship between a photographic film assemblage, which forms a part of the invention, and a pivotally mounted supporting structure for the camera's first and second pressure-applying means;
FIG. 5 is an enlarged end view showing the relationship between a film cassette, an exposed film unit, and the second pressure-applying means during the spreading of a processing liquid between layers of the film unit, the film unit elements being greatly enlarged for clarity of understanding;
FIG. 6 is a bottom view of the film cassette shown in FIGS. 3-5;
FIG. 7 is a diagrammatic plan view of a film unit showing, in dotted lines, an advancing wave front of processing liquid as it would appear without benefit of the present invention; and
FIG. 8 is a view similar to FIG. 7 showing, in dotted lines, an advancing wave front as it would appear with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference in now made to the drawings, and in particular to FIGS. 1 and 2 wherein is shown a folding camera 10 of the instant or self-developing type. Note should be taken at this time that although the invention is described in relation to a folding camera, the invention is equally applicable to a non-folding camera The camera 10 includes a first or main housing 12 having a loading door 14 in a bottom wall thereof. The first housing 12 also includes front and rear walls 18 and 20, respectively, and end walls 22 and 24. The door 14 is pivotally connected to the end wall 22 of the main housing 12 by a hinge (not shown) which is generally parallel with the axis of the camera's objective lens 28 and perpendicular to the forward and rear walls 18 and 20. The main housing 12 further includes a top wall 30 having a pair of spaced flanges 32 and 34 extending upwardly therefrom so as to define a recess 36.
The camera 10 further includes a second housing 38 which is pivotally coupled to the first housing 12 about an axis (not shown) which is generally parallel with the rear wall 20 for movement between an inoperative position (see FIG. 1), wherein it is nested within the recess 36, and its operative position, as shown in FIG. 2. The second housing 38 supports the aforementioned objective lens 28, a shutter assembly, and a photocell window 40. A top wall 42 of the second housing includes a recess which is adapted to receive a third housing 46 of the camera 10 when the camera is being collapsed or folded.
The third housing 46 is pivotally coupled to the rear wall 20 of the first housing 12 about a horizontal axis (not shown) which is generally parallel with the rear wall 20. The third housing 46 is provided with a recess 50 for pivotally receiving therein a fourth housing 52.
The fourth housing 52 supports a source of artificial illumination such as a strobe 54 and a ranging window 56. The fourth housing 52, as well as the second and third housings 38 and 46, is biased into the erect position shown in FIG. 2. Further, the fourth section 52 is adapted to be nested within the recess 50 prior to the third housing 46 being moved into the recess 44.
When the various housings are in the positions shown in FIG. 2, actuation of an exposure cycle initiation button 58 (see FIG. 1) located within a recess in the top wall 30 of the first housing 12 is effective to cause image bearing light rays to enter the camera 10 via the lens 28 and be reflected downwardly by a mirror (not shown) onto a film unit.
The camera 10 includes a film chamber 60 which is accessible via the loading door 14. The film chamber 60 is adapted to receive a film assemblage 70. The film chamber 60 is defined in part by a wall 62 which functions to locate a film cassette 72 of the assemblage 70 in position for the sequential exposure of a plurality of film units 74 stacked therein.
The film assemblage 70 includes, in addition to the film cassette 72 and the film units 74, biasing means (not shown) for resiliently urging the stack of film units 74 toward a forward wall 76 of the film cassette 72. The forward wall 76 is provided with a generally rectangular shaped exposure aperture 78 which is adapted to be located in alignment with a correspondingly shaped aperture 64 located in the wall 62. The forward wall 76 cooperates with a pair of side walls 80 and 82, leading and trailing end walls 84 and 86, and a bottom wall 88, to define a chamber for receiving the stack of film units 74. The aforementioned biasing means is located between the bottom wall 88 and an adjacent endmost film unit 74 so as to urge the opposite endmost film unit 74 in the stack against the interior surface of the forward wall 76 with (1) its photosensitive layer 90 (see FIG. 5) located in alignment with the exposure aperture 78, (2) its leading end located in position to be moved through an elongate egress 92 in the cassette's leading end wall 84, and (3) its trailing end located adjacent the trailing end wall 86. The leading end of each film unit 74 is provided with a pod or container 94 of processing liquid 96 (see FIG. 5) and the trailing end of each film unit is formed with a trap 98 for receiving any excess processing liquid 96.
Extending downwardly from the bottom wall 88 and integrally formed therewith is a protuberance 100 which functions to control the distribution of the processing liquid to be spread between layers of an exposed film unit. The protuberance 100 slopes downwardly and rearwardly as it extends from the leading end wall 84 to its left terminus 102 (as viewed in FIG. 3) to define a surface 104 having upwardly sloping lateral ends 106 and 108 (see FIG. 5).
The side wall 84 of the film cassette 72 has a tab 110 which extends outwardly therefrom. As will be more fully described hereinafter, the tab 110 is adapted to cooperate with camera structure to adjust the location of a pressure-generating gap relative to a path of travel of an exposed film unit as the latter enters the gap so as to increase or decrease the thickness of a layer of processing liquid to be spread between layers or elements of the film unit.
The camera 10 includes a structure 112 for supporting (1) a first pressure-applying means in the form of elongate spread rollers 114 and 116, and (2) a second pressure-applying means in the form of a laterally extending plate 118. The opposite ends of the spread rollers 114 and 116 are rotatably supported in one end of a pair of laterally spaced arms 120 and 122 so as to define a pressure generating gap 124 therebetween. The roller 116 is mounted for movement toward and away from the roller 114. The opposite ends of the arms 120 and 122 are rotatably supported on a cylindrical rod 126. In FIG. 3, the arm 120 is shown in phantom lines so as to provide a better view of the camera's first and second pressure-applying means and the surfaces 104 and 106 of the protuberance 100. Also in FIG. 3, the pressure generating gap 124 is shown as being located in alignment with a path of travel that an exposed film unit 74 would take as it moves from the film cassette 72 to a film storage 128, said path of travel being indicated by the line 130. The plate 118 extends between the ends of another pair of arms 132 and 134, the opposite ends of which are also rotatably supported by the rod 126. Thus, as best seen in FIG. 4, the second pressure-applying means is adapted to be independently rotated about the rod 126 without affecting the movement of the first pressure-applying means. Suitable means, such as a spring schematically shown in FIG. 3 at 136, is provided for resiliently biasing the arm(s) 134 and 136 is a clockwise direction against a stop (not shown). A separate spring 138 is provided for resiliently biasing the arm(s) 132 and 134 in a clockwise direction into engagement with a stop 140. The force of the spring 138 may be increased or decreased by moving an adjusting cam 142 to the left or right, respectively, as shown in FIG. 3.
When a film cassette 72 is positioned within the film chamber 60, the tab 110 engages an upwardly extending portion 144 of the arm 120 and causes the first pressure-applying means (arms 118, 120 and rollers 116 and 112) to be rotated in a counterclockwise direction about the rod 126 until the film cassette 72 is in the position shown in FIG. 3 and the gap 124 properly located relative to the path of travel 130; the degree of such rotation being a function of the thickness of the tab 110 or its location on the side wall of the film cassette 72, which in turn is a function of a predetermined desired thickness for a layer of processing liquid 96 to be spread between layers of the particular film units located in the film cassette 72.
At the same time that the above spacial relationship between the gap 124 and the path of travel 130 is being established a second relationship is being established, namely, the juxtapositioning of the protuberance 100 on the bottom wall 88 of the film cassette 72 and the second pressure-applying means (the plate 118). Preferably, this latter relationship is established by the protuberance 100 lightly engaging the top surface of the plate 118 such that the sloping surface 104 of the protuberance cooperates with a curved surface 146 of the plate 118 to define a converging passage to facilitate the introduction of a film unit between the protuberance 100 and the plate 118. Alternatively, the stop 140 may also function to provide for some initial gap between the two members.
Once the film cassette 72 has been properly located in the position shown in FIG. 3, and the film assemblage's dark slide (not shown) removed thereby uncovering the upper endmost film unit 74 in the stack, actuation of the button 58 is effective to initiate an exposure cycle. Subsequent to the photographic exposure of the endmost film unit 74, a battery energized motor (not shown) is used to drive a film advancing member 144 (first advancing means) in a reciprocating manner such that it enters an ingress 146 (see FIG. 4) formed in the forward and trailing end walls 76 and 86, respectively, of the film cassette 72 and engages the endmost film unit by its trailing edge and moves it in a first direction toward the exterior of the film cassette 72 via the egress 92. As the endmost film unit 74 emerges from the film cassette 72, its leading end enters the bite between laterally spaced pairs of edge rollers 148 and 150, only one pair being shown. The pairs of rollers 148 and 150 are driven in a direction which continues the movement of the exposed endmost film unit 74 along the path 130 in said first direction and then in a second direction, generally opposite to the first direction. A curved passageway 152 defined by a laterally extending curved plate 154 and a cylindrical member 156 facilitates such reversal. As the film unit's leading end emerges from the passageway 152, it enters the bite of another set of laterally spaced pairs of edge rollers 158 and 160 (only one pair shown) which continue the advancement of the endmost film unit 74 in the second direction as its trailing end leaves the bite of the first set of edge rollers 148 and 150. The pairs of edge rollers 148, 150 and 158, 160 are adapted to engage only the lateral margins 162 and 164 of the endmost film unit 74. Thus, the two sets of edge rollers and the means defining the curved passageway 152 define a second means for continuing the movement of the endmost film unit in the first direction and then in a second direction generally opposite to the first direction.
The second set of pairs of edge rollers 158 and 160 continue to drive the film unit in the second direction between the protuberance 100 and the second pressure applying means (plate 118) and into the bite of the spread rollers 114 and 116, at least one of which is driven in a direction to continue the advancement of the film unit. As is well known in the art, the rollers 114 and 116 function to rupture the container 94 of processing liquid and spread its contents 96 in a layer between elements of the film unit, e.g., the photosensitive sheet 90 and an image-receiving sheet 162, so as to initiate the formation of a visible image within the sheet 162 while simultaneously advancing the film unit into the lighttight storage chamber 128. As the film unit 74 enters the chamber 128, its leading end engages a pair of ramps 166 166 (only one shown) located on the right hand ends of a pair (only one shown) of inwardly extending horizontal surfaces 168. The drive of the spread rollers 114 and 116 propel the film unit 74 up the ramps 166 and onto the surfaces 168 which function to support only the lateral sides 162 and 164 of the film unit. After a predetermined period of time, which period is of a length sufficient for the processing of the film unit 74 to reach a point where its emerging image is no longer susceptible to being adversely affected by ambient light, an opaque shade 170 may be moved from covering relation to a window 172 in the door 14 to allow viewing of the image within the film unit 74. The film unit may then be removed from the film chamber 128 via an exit (not shown) or left in place and the shade 170 returned to its lighttight position relative to the window 172 in preparation for a second exposure. Each subsequent film unit 74 entering the storage chamber 128 will automatically assume the lowermost position because of the placement of the ramps 166, thus assuring that the last film unit to be exposed will be available for viewing while in the storage chamber.
When the spread rollers 114 and 116 rupture the pod 94 at the leading end of the exposed film unit 74, the processing liquid 96 emerges therefrom as a wave whose front is controlled by the specific shape of the protuberance 100. In the present form of the invention, the intermediate portion 104 of the protuberance 100 retards the adjacent portion of the wave front of the processing liquid 96 while the upwardly tapering or sloping lateral ends 106 and 108 gradually offer less and less resistance to the adjacent portions of the wave front. Thus, the net effect of the protuberance 100 on the wave front is to straighten out its normally tongue shape configuration, as shown in FIG. 7 where opposite end corners 174 and 176 of the film unit may receive too little or none of the processing liquid, to one where the wave front is generally perpendicular to the direction of movement of the film unit 74 thereby providing a more uniform distribution of the processing liquid 96.
Since certain changes may be made in the above described invention without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. For example, while the protuberance 100 has been shown as a unitary member having a specific configuration, it could be comprised of a plurality of separate smaller members whose configurations and spacial relation to each other would be a function of the specific control to be applied to the wave front of the processing liquid.
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Photographic apparatus for supporting a cassette containing a plurality of film units of the self-developing type in position for exposure. Subsequent to its exposure, the film unit is moved out of the cassette and redirected to a liquid spread roller assembly located below the cassette. The roller assembly includes
(1) a pair of rollers for rupturing a container of processing liquid associated with a leading end of the film and spreading its contents between layers of the film unit to initiate the formation of a visible image, and
(2) structure which cooperates with the external configuration of the cassette for controlling the thickness and/or shape of the processing liquid being spread.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a non-provisional application based upon U.S. provisional patent application Ser. No. 61/182,420, entitled “INTEGRATED AIR INTAKE SYSTEM”, filed May 29, 2009.
FIELD OF THE INVENTION
[0002] The invention relates to the structure and operation of air intake systems and methods of supplying intake air to internal combustion engines. More specifically, it relates to a method, system and structure for supplying ambient or non-preheated air to an internal combustion engine for a work vehicle or mobile construction machine such as, for example, a wheeled feller buncher.
BACKGROUND OF THE INVENTION
[0003] Most mobile construction machines employ above-hood engine air intakes. The above-hood air intake is usually covered by a shield to prevent the entrance of rain and other precipitation. Above-hood air intakes are typically designed to be low-profile, i.e., have as small of a visual signature as possible. However, these intakes are required to be high enough to minimize the entry of dust and other debris settling near the hood and far enough from the exhaust stack associated with these machines to minimize the intake of preheated air. Pre-cleaners are typically used in above-hood air intake designs to remove some of the debris from the intake air and, thereby, extend engine air filter life.
[0004] As previously indicated, conventional above-hood air intake systems for work vehicles tend to obstruct visibility for the work vehicle operator. This is a consequence of attempting to meet the noted demands of locating the air intake (1) high enough to eliminate or minimize the entry of dust and debris from the hood and (2) far enough from the exhaust stack to eliminate or minimize the intake of preheated air. These disadvantages are only intensified by the relatively large pre-cleaners that are often attached to the entry point of such systems in high debris environments.
[0005] Some mobile construction machines are provided with conventional under hood air intake systems having air intake tubes with inlet openings located in the engine compartment. When these systems have perforations in the hood of the engine compartment, the inlet opening is arranged to prevent the intake of rain and other precipitation. Thus, the inlet opening of the air intake is angled such that the intake air enters in a direction that is horizontal to or at least partially opposite to the direction of the precipitation as it enters the engine compartment. Other under hood air intake designs include air intake tubes that are routed to compact cooling package areas where the air inlets are located in areas separate from the engine compartment.
[0006] A major disadvantage of many conventional under hood air intake systems where the intake port is located in the engine compartment is that they tend to intake preheated air via convection and radiation with respect to the engine. This is accentuated when these systems have perforations in the hood as the intake port must be angled away from the perforations and more toward the engine compartment with air preheated by heat exchanger(s) and the engine. Other under hood air intake designs tend to avoid this problem but all under hood designs tend to use only screens and filters to remove debris as the use of pre-cleaners under the hood tends to: (1) take up too much precious space, i.e., premium space; and (2) the inconvenience caused by the debris typically ejected by such devices.
SUMMARY OF THE INVENTION
[0007] The invention overcomes each of the above disadvantages by providing an air intake system integral to and formed by a hood of an engine enclosure as well as other conventional components within the engine enclosure. The engine enclosure is formed by at least the hood, two sidewalls, a grille and a screen. An insulated air duct forms an integral part of the hood and is in communication with a filter for engine air intake. The air entering the air duct may be moved into the engine enclosure via a fan for the purpose of moving air from the ambient surroundings outside of the vehicle to a location inside the vehicle and, typically, through a heat exchanger. The air may also be pre-cleaned by a screen as well as relative movement between debris and air prior to and after pre-cleaning of the air by the screen. The entrance to the air duct is preferably located such that the ambient air entering the air channel tends toward ambient temperature, i.e., air that has not been preheated via passage through the heat exchanger. Thus, a preferable location for the entrance to the air duct is, horizontally, between the screen and the heat exchanger and, vertically, toward the top of the screen and the heat exchanger. Further, the entrance passage is preferably substantially orthogonal to the axis of the fan or at an angle greater than 90 degrees to the axis of the fan or the flow direction of the air. Such an arrangement gives the air a chance for a first pre-cleaning via the screen as well as a second pre-cleaning via the general inability of debris to change direction and move upwards and into the entrance passage to the same extent as air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Embodiments of the invention will be described in full detail with references to the following Figures, wherein:
[0009] FIG. 1 is a view of a work vehicle in which the invention is used;
[0010] FIG. 2 is an oblique view of a rear portion of the vehicle illustrated in FIG. 1 ;
[0011] FIG. 3 is an oblique cutaway view of the engine enclosure showing a view of an exemplary air intake system;
[0012] FIG. 4 is an oblique cutaway view showing the exemplary air intake system of FIG. 3 illustrating a connection between the filter and a turbocharger;
[0013] FIG. 5 is a side view cutaway of a portion of the air intake system of FIGS. 3 and 4 illustrating a bolted connection between the screen and the grille of the vehicle of FIG. 1 , a sealed assembly between first and second portions of the air channel, and an entrance passage to the air channel;
[0014] FIG. 6 is a close-up view of a portion of FIG. 5
[0015] FIG. 7 is a rear view cutaway of a cylinder through the air channel for easy access to a fill cap for the heat exchanger;
[0016] FIG. 8 is a forward cutaway of the engine enclosure showing the interface between the air filter duct and the air intake duct;
[0017] FIG. 9 is a view of first air intake duct portion isolated; and
[0018] FIG. 10 is a view of the second air intake duct portion isolated.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] FIG. 1 illustrates an exemplary embodiment of a work vehicle in which the invention is used. The particular work vehicle illustrated in FIG. 1 is a wheeled feller buncher 1 ; an articulated vehicle having a front body portion 20 connected to a rear body portion 30 via pivots 40 , the wheeled feller buncher 1 being steered by pivoting of the front body portion 20 relative to the rear body portion 30 in a manner well known in the art. The rear body portion 30 includes an engine enclosure 100 having a first sidewall 101 , a second sidewall 102 and a hood 100 a with an integrated air intake duct 110 and a supporting structure 113 ( FIG. 5 ).
[0020] FIGS. 2 and 3 illustrate that, in this exemplary embodiment, a grille screen 117 forms a portion of the engine enclosure 100 . As shown in FIGS. 5 and 6 , in this particular embodiment, the grille screen 117 includes a grille bar support 117 a , a plurality of grille bars 117 b and a screen 118 with a multiplicity of holes, each having an approximate diameter of 2.5 mm. Each grille bar 117 b is, in this embodiment, welded to the grille bar support 117 a . The grille screen is assembled by locating the screen 118 between the grille bar support 117 a and the plurality of grille bars 117 b as shown in FIGS. 5 and 6 and attaching it to the grille bar support 117 a via a plurality of fasteners such as, for example, the bolt 119 and welded nut 119 a arrangement shown in FIGS. 5 and 6 . The grille screen 117 acts as a door for the engine enclosure 100 ; it is pivotally connected to a hinge 117 c and swings outwardly and away from the vehicle in a manner well known in the art. The grille bar support 117 a and the plurality of grille bars 117 b , among other things, serve a decorative function and act as a support and protective structure for the screen 118 .
[0021] FIG. 3 also shows the intake air duct 110 which, in this embodiment, extends along a significant portion of the length L of the hood 100 a as well as a significant portion of the width W of the hood 100 a . As illustrated in FIG. 3 , the air intake duct 110 is an assembly including a first intake air duct portion 112 and a second intake air duct portion 111 . As illustrated in FIG. 7 , the first air intake duct portion 112 is formed by two channels, including; a lower channel 112 d and an upper channel 112 c forming a rear outer shell of the hood, i.e., a rear hood cover 112 g with flanges 112 h . The lower and upper channels 112 d and 112 c are welded along their lengths at W 1 , W 2 , W 3 and W 4 . As shown in FIGS. 3 and 5 , a rectangular opening toward the rear end of the first air intake duct portion 112 forms a part of an air entrance passage 112 b which allows air to enter the air intake duct 110 in a direction that is generally orthogonal to the flow of air between the grille screen 117 and the heat exchanger 116 . An air guidance structure 113 completes the air entrance passage 112 b . The air guidance structure is welded to the frame of the vehicle in a well known manner. Seals 113 a , 113 b are provided between the first air intake duct portion 112 and the air guidance structure 113 to provide a barrier to leakage of air into or out of the entrance passage 112 b as air from the air guidance structure 113 moves into the first intake air duct portion 112 .
[0022] Welded to each channel and vertical thereto is a cylinder 112 a providing an access hole 116 b to a fill cap 116 a of the heat exchanger 116 . The cylinder 112 a is welded along its circumference at each end to the upper and lower channels 112 c , 112 d at W 5 and W 6 .
[0023] As illustrated in FIGS. 1 and 8 , the second air intake duct portion 111 is formed via first and second forward channels 111 c , 111 d and a supporting structure which is formed by a plate 111 b welded along its length, at W 7 and W 8 to the internal side of a hood shell, i.e., forward hood structure 111 a which is, in this case, of trapezoidal shape cross sectionally. As shown in FIG. 8 , the ends of the first and second forward channels 111 c , 111 d are attached to the plate 111 b via weldments along their lengths at W 9 , W 10 , W 11 and W 12 as illustrated. As illustrated a gap 111 f is formed between the first and second forward channels 111 c , 111 d . The width G 1 of the first gap 111 f and the substantially static air therein provide insulation, i.e., a barrier to the transfer of heat from inside the engine enclosure 100 . As shown in FIG. 8 a second gap 111 e is formed between the plate 111 b and the hood structure 111 a . The width G 2 of the second gap 111 e as well as the static air therein provide insulation, i.e., a barrier to the transfer of heat between the outside ambient air and the air passing through the second air intake duct portion 111 . In this exemplary embodiment, G 1 is approximately 19 mm and G 2 is approximately 22 mm. The width of the air intake duct 110 and the gap widths internal to the air intake duct 110 providing the insulation are designed to optimize air flow within the intake air duct 110 while maintaining improved visibility for the operator, i.e., a low hood profile. The pressure for optimal flow varies with configuration but, is, in this exemplary embodiment, approximately 3.3 kPa. This value is subject to change with changes in the configuration and desired performance demands from the overall design.
[0024] The rear hood cover 112 g of the first air intake duct portion 112 and the forward hood structure 111 a of the second air intake duct portion 111 are bolted to the frame in a manner well known in the art. As illustrated in FIG. 5 , the lower channel 112 d is longer than the upper channel 112 c . As illustrated in FIGS. 5 , 7 and 8 , upon assembly of the first air intake duct 112 to the second air intake duct portion 111 , the upper channel 112 c butts up against a seal 110 a to prevent debris and water from the external environment from entering the air intake duct 110 at the interface between the first air intake duct portion 112 and the second air intake duct portion 111 . As illustrated in FIG. 5 , the lower channel 112 d slides into the second air intake duct portion 111 . A seal 110 b is also provided to prevent leakage of air into and out of the air intake duct 110 at the interface between the first air intake duct portion 111 and the second air intake portion 112 ; this seal 110 b provides a barrier to air flow between air in the engine enclosure 100 and the air intake duct 110 . Both of the seals 110 a , 110 b are, in this exemplary embodiment, attached to the second air intake duct portion in a manner well known in the art. A labyrinth pattern at the forward end of the upper channel 112 c provides extra sealing against external moisture and debris.
[0025] As illustrated in FIGS. 3 and 8 , a sealed opening 111 j is provided for a first air filter duct 114 a toward the forward end of the second air intake duct portion 111 . The sealed opening is provided by a cylinder 111 g welded toward its ends to bottom portions of the first and second forward channels 111 c , 111 d . Holes, in this exemplary embodiment, are provided in the first and second forward channels 111 c , 111 d to allow for passage of the air filter intake duct 114 a into the second air intake duct 111 . A fifth seal 111 h is attached to the outside surface of second forward channel 111 d in a manner well known in the art to prevent leakage of air at the interface of the second air intake duct portion 111 and the air filter duct intake 114 a as air flows from the second air intake duct portion 111 into the air filter intake duct 114 a and eventually to the air filter 114 to which the air filter intake duct is attached. As shown in FIGS. 3 and 4 , the air filter 114 is attached to the frame in a manner well known in the art, e.g., straps 114 b.
[0026] As illustrated, an air filter supply duct 120 provides communication between the air filter 114 and a turbocharger 121 . An engine 55 operates in conjunction with the turbocharger 121 in a manner well known in the art. As the engine operates, the heat and pressure of the exhaust gas passes to the turbocharger 121 which lowers the pressure in the supply duct and, thereby, lowers the pressure in the air filter 114 , the air filter intake duct 114 a and the air intake duct 110 . The lower pressure in the air intake duct 110 causes the flow of air into the air entrance passage 112 b.
[0027] In operation, the fan 115 draws outside air, i.e., a first ambient air through the grille screen 117 . As the air passes through the grille screen 117 , the screen blocks the passage of larger debris, allowing only debris that may pass through the holes 118 a provided in the screen. This results in a second ambient air, i.e., air from which a portion of debris has been removed via the screen 118 . As the second ambient air moves toward the heat exchanger 116 other debris tends to move along with it or to fall out of it via gravitational effects. Demands of the engine, communicated via the turbocharger, cause a portion of the air between the screen 118 and the heat exchanger 116 to flow into the entrance passage 112 b . The air flowing into the entrance passage 112 b constitutes a third ambient air as some debris has been removed from it via the above gravitational effects and the passage of some debris to and through the heat exchanger. Some of the remaining debris lacks sufficient ability to turn upwards and move into the entrance passage 112 b to the same extent as air.
[0028] Third ambient air, upon moving into the first air intake duct portion 112 must make a sharp turn as the entrance passage 112 b is, in this exemplary embodiment, orthogonal to the air intake duct 110 . Some additional debris may drop out and be removed at this point. The third ambient air passes through the air intake duct 110 and into the air filter 114 via the air filter intake duct 114 a . The filter 114 then removes another portion of the debris and the air emerging from the filter enters the filter supply duct 120 . The air entering the filter supply duct 120 is a fourth ambient air, i.e., third ambient air with a portion of the debris removed by the filter 114 . The fourth ambient air is then supplied to the turbocharger via the filter supply duct 120 and then supplied to the engine 55 via the turbocharger 121 in a manner well known in the art.
[0029] Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims. For example, an air intake duct may be constructed and insulated using several alternative methods. Some of these methods might include: (1) forming a second air intake portion by using fully formed inner and outer ducts; (2) providing heat insulation for both portions of an air intake duct; (3) making an air intake duct a single piece; (4) locating the air intake duct at an angle greater or less than that of the hood; (5) locating a fan and heat exchanger at a level that is lower than that of the screen. The plates, channels and hood covers of this particular embodiment are metallic but could, conceivably, be formed from other materials of high strength or low conductivity, etc. Other variations of materials, arrangement and construction would apply to the air duct as well as any other portion of the invention described herein.
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An engine air intake system is provided which is formed by an engine compartment. A fan and a grille screen are used to remove a portion of debris from air external to the vehicle. After the air is partially cleaned via the grille screen, it moves toward a heat exchanger carrying a portion of the remaining debris with it. A portion of the debris may fall out of the air via gravitational effects. A portion of the air then moves up and into an entrance passage for an air intake duct that is integrated with the hood of the engine enclosure, this portion having been further cleaned via debris passage to and through the heat exchanger as well as gravitational effects. The air then travels through the air intake duct and passes through an air filter where a portion of the remaining debris is removed prior to the air being supplied to the engine intake.
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BACKGROUND
[0001] The invention relates to an electronic apparatus, and in particular to an electronic apparatus providing rapid assembly/disassembly and height adjustment functions.
[0002] A thin TV or display often comprises a monitor and a pedestal. The thin TV or display is assembled by fastening bolts to the monitor and pedestal.
[0003] A few drawbacks exist when the monitor is fixed to the pedestal by bolts. As the size of the thin TVs (or monitors) increases, the weight thereof increases correspondingly. When a thin TV or display is assembled, the monitor and pedestal are often placed at a sloped angle or horizontally. The display panel of the monitor is thus easily scraped or damaged. In another aspect, when the monitor and pedestal are not placed at a sloped angle or horizontally, at least two operators are required to assemble the thin TV or display, thereby increasing the number of laborers. Moreover, a screwdriver is required for assembly of the monitor and pedestal, causing inconvenience. Furthermore, when the height of the thin TV (or monitor) is adjusted, the bolts must be removed from the monitor and pedestal. The bolts are again fastened to the monitor and pedestal after the height of the thin TV (or monitor) is adjusted, further increasing complexity of height adjustment.
SUMMARY
[0004] Accordingly, an exemplary embodiment of the invention provides an electronic apparatus providing height adjustment functions. The electronic apparatus comprises a pedestal, a main body, and a positioning mechanism. The pedestal comprises a guiding member. The main body is detachably connected to the guiding member and comprises a guiding groove located in which the guiding member relatively slides. The positioning mechanism is movably disposed in the guiding member and guiding groove to control the sliding position of the guiding member with respect to the guiding groove.
[0005] In an embodiment of the electronic apparatus, the guiding member further comprises a first through hole. The guiding groove further comprises at least one positioning hole. The positioning mechanism engages the positioning hole via the first through hole, controlling the sliding position of the guiding member with respect to the guiding groove.
[0006] In an embodiment of the electronic apparatus, the guiding member further comprises a second through hole. The positioning mechanism further comprises an engaging member, a resilient member, and a retardant member. The second through hole is coaxially connected to the first through hole. The engaging member is disposed in the first and second through holes. The retardant member covers and is fixed on the second through hole. The resilient member is disposed in the second through hole and between the engaging member and the retardant member, providing resilience to the engaging member.
[0007] In an embodiment of the electronic apparatus, the retardant member further comprises a third through hole and the engaging member further comprises a pillar, an abutting portion, and an engaging portion. The third through hole is coaxially connected to the second through hole. The abutting portion is between the pillar and the engaging portion and is disposed in the second through hole. The pillar is disposed in the second and third through holes and extends outside the third through hole. The engaging portion is disposed in and extends outside the first through hole, engaging the positioning hole. The resilient member is between the abutting portion and the retardant member and is disposed at the periphery of the pillar.
[0008] In an embodiment of the electronic apparatus, the main body further comprises a guiding sloped surface connected to the guiding groove. The engaging portion engages the positioning hole by sliding on the guiding sloped surface and guiding groove.
[0009] In an embodiment of the electronic apparatus, the resilient member comprises a spring.
[0010] In an embodiment of the electronic apparatus, the cross sections of the guiding groove and guiding member are substantially the same.
[0011] In an embodiment of the electronic apparatus, the main body comprises a monitor.
DESCRIPTION OF THE DRAWINGS
[0012] The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
[0013] FIG. 1 is an exploded perspective view of the electronic apparatus of an embodiment of the invention;
[0014] FIG. 2 is a partial enlarged view of FIG. 1 ;
[0015] FIG. 3 is a partial assembly cross section of the guiding member and positioning mechanism of the electronic apparatus of an embodiment of the invention;
[0016] FIG. 4 is a schematic view showing assembly of the electronic apparatus of an embodiment of the invention;
[0017] FIG. 5 is a schematic view showing assembly following FIG. 4 ;
[0018] FIG. 6 is a schematic view showing assembly following FIG. 5 ; and
[0019] FIG. 7 is a schematic view showing assembly following FIG. 6 .
DETAILED DESCRIPTION
[0020] Referring to FIG. 1 and FIG. 2 , the electronic apparatus 100 comprises a pedestal 110 , a main body (monitor) 120 , and two positioning mechanisms 130 . The electronic apparatus 100 is, for example, a television. Although provided with two positioning mechanisms 130 , the electronic apparatus 100 is not limited to having two positioning mechanisms 130 . Namely, the electronic apparatus 100 may selectively comprise only one positioning mechanism 130 .
[0021] The pedestal 110 comprises two opposing guiding members 111 . Each guiding member 111 comprises a first through hole 112 and a second through hole 113 coaxially connected to the first through hole 112 . In this embodiment, the diameter of the second through hole 113 exceeds that of the first through hole 112 . Specifically, the diameters of the first through hole 112 and second through hole 113 can be designed as required. Namely, the diameter of the second through hole 113 may be, alternatively, less than that of the first through hole 112 . Moreover, the profile of the pedestal 110 can be changed as required, and the pedestal 110 is not limited to having two opposing guiding members 111 . Namely, the pedestal 110 may selectively comprise only one guiding member 111 .
[0022] The main body 120 is detachably connected to the guiding members 111 of the pedestal 110 . Specifically, the main body 120 comprises two guiding grooves 121 corresponding to the guiding members 111 . In this embodiment, the cross section of the guiding grooves 121 is substantially the same as that of the guiding members 111 . Additionally, each guiding groove 121 comprises a plurality of positioning holes ( 122 a , 122 b ) formed therein and located on different levels. Moreover, the main body 120 comprises two guiding sloped surfaces 123 corresponding and connected to the guiding grooves 121 . Similarly, the main body 120 is not limited to having two guiding grooves 121 and two guiding sloped surfaces 123 . Alternatively, the main body 120 may selectively comprise only one guiding groove 121 and only one guiding sloped surface 123 .
[0023] Moreover, when the main body 120 is a monitor, the guiding grooves 121 can be formed on the back of the monitor and a display panel (not shown) can be disposed on the front thereof.
[0024] Each positioning mechanism 130 is movably disposed in each guiding member 111 of the pedestal 110 and each guiding groove 121 of the main body 120 . Specifically, each positioning mechanism 130 comprises an engaging member 131 , a resilient member 132 , and a retardant member 133 . As shown in FIG. 2 and FIG. 3 , the retardant member 133 covers and is fixed on the second through hole 113 of the guiding member 111 . Additionally, the retardant member 133 comprises a third through hole 133 a coaxially connected to the second through hole 113 . The engaging member 131 comprises a pillar 131 a , an abutting portion 131 b , and an engaging portion 131 c . The abutting portion 131 b is between the pillar 131 a and the engaging portion 131 c and is disposed in the second through hole 113 . The pillar 131 a is disposed in the second through hole 113 and third through hole 133 a of the retardant member 133 and extends outside the third through hole 133 a . The engaging portion 131 c is disposed in the first through hole 112 and extends outside the first through hole 112 . The resilient member 132 is disposed in the second through hole 113 and between the abutting portion 131 b of the engaging member 131 and the retardant member 133 . Specifically, the resilient member 132 is disposed at the periphery of the pillar 131 a of the engaging member 131 . Accordingly, the engaging member 131 of the positioning mechanism 130 can move forward and backward, as indicated by arrow A of FIG. 3 .
[0025] Moreover, the resilient member 132 is, for example, a spring.
[0026] The following description is directed to assembly and disassembly of the electronic apparatus 100 (such as a television).
[0027] When the main body (monitor) 120 is positioned on the pedestal 110 , as shown in FIG. 4 , the guiding grooves 121 of the main body 120 are respectively aimed at the guiding members 111 of the pedestal 110 and are moved downward (or relatively). As shown in FIG. 5 , the guiding members 111 are simultaneously inserted into the corresponding guiding grooves 121 . At this point, the engaging portion 131 c of each engaging member 131 slides on each guiding sloped surface 123 of the main body 120 . Then, the engaging portions 131 c and guiding members 111 simultaneously slide in the guiding grooves 121 . Because of the profiles of the guiding grooves 121 and guiding members 111 , the engaging portions 131 c of the engaging members 131 are pushed into (the second through holes 113 of) the guiding members 111 . At this point, the abutting portion 131 b and pillar 131 a of each engaging member 131 move toward the third through hole 133 a , and the resilient member 132 disposed between the abutting portion 131 b and the retardant member 133 is compressed to provide resilience. The main body 120 continues to move downward until the engaging portion 131 c of each engaging member 131 slide to the first positioning hole 122 a in each guiding groove 121 . The engaging portion 131 c rapidly ejects and engages the first positioning hole 122 a by the resilience provided by the resilient member 132 , as shown in FIG. 6 . At this point, the main body 120 and pedestal 110 are completely assembled.
[0028] Moreover, when the height of the main body 120 relative to the pedestal 110 is adjusted, the engaging member 131 (or pillar 131 a ) can be pulled outward to separate the engaging portion 131 c from the first positioning hole 122 a . At this point, the resilient member 132 disposed between the abutting portion 131 b and the retardant member 133 is compressed to again provide resilience. The main body 120 is then moved downward and the engaging member 131 (or pillar 131 a ) is released. When the engaging portion 131 c of each engaging member 131 slides to the second positioning hole 122 b in each guiding groove 121 , the engaging portion 131 c rapidly ejects and engages the second positioning hole 122 b by the resilience provided by the resilient member 132 , as shown in FIG. 7 . At this point, adjustment of the height of the main body 120 with respect to the pedestal 110 is complete. Specifically, the electronic apparatus 100 or main body 120 is not limited to having only two positioning holes 122 a and 122 b . Namely, the main body 120 may selectively comprise more positioning holes in each guiding groove 121 , enabling different adjustment of the height of the main body 120 with respect to the pedestal 110 .
[0029] In another aspect, when the main body 120 is separated from the pedestal 110 , the engaging member 131 (or pillar 131 a ) can be pulled out of the first positioning hole 122 a or second positioning hole 122 b. The main body 120 is then simultaneously moved upward (or relatively) until it is completely separated from the pedestal 110 .
[0030] In conclusion, the electronic apparatus 100 can be rapidly assembled and disassembled, and the height thereof can be easily adjusted. Moreover, the electronic apparatus 100 can be rapidly assembled and disassembled in the absence of any assisting tool. Thus, troubles of missing of bolts are prevented.
[0031] While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
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An electronic apparatus. A pedestal includes a guiding member. A main body is detachably connected to the guiding member and includes a guiding groove in which the guiding member relatively slides. A positioning mechanism is movably disposed in the guiding member and guiding groove, controlling the sliding position of the guiding member with respect to the guiding groove.
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This is a continuation of U.S. application Ser. No. 08/640,156, filed Apr. 30, 1996, now U.S. Pat. No. 5,788,710.
FIELD OF THE INVENTION
This invention relates to removing calculi and other objects.
BACKGROUND OF THE INVENTION
In a stone retrieval procedure, a calculus (stone) is removed from, e.g., the bile duct using a catheter device that is passed through an endoscope. The catheter device includes a collapsible basket that is extended from a sheath to capture the stone for removal.
In a lithotripsy procedure, the stone is crushed either to facilitate natural passage or to facilitate removal with a basket. This procedure can be performed with a catheter device that can apply large collapsing force to the basket, which crushes the captured stone. Many other medical procedures also involve grasping, sampling, removal, and/or crushing objects in the body.
SUMMARY OF THE INVENTION
In an aspect, the invention features an instrument for treating an internal organ which is obstructed by a calculus. The instrument includes an elongate catheter sheath extending along an axis from a proximal end to a distal end that is sized for insertion into the organ. A basket-form calculus grasper is formed of flexible wires and adapted to be extended from and withdrawn within the distal end of the catheter sheath such that, when extended from the distal end of the sheath, the wires are spaced to permit passage of the calculus and when withdrawn at least partially into the sheath, the wires collapse in a manner to capture the calculus. A tension element is coupled to the grasper. A handle at the proximal end of the catheter sheath receives the tension element and houses an operating assembly. The operating assembly permits application of axial force to the tension element for extending or withdrawing the grasper from the distal end of the sheath and permits rotating the grasper about the axis. The operating assembly includes a manual actuator and a mechanical actuator. The manual actuator is coupled to the tension element and arranged for applying axial force to the tension element for extending the grasper from the distal end of the sheath and for imparting rotational motion to the tension element for rotating the grasper about the instrument axis to a desired orientation. The mechanical actuator is arranged to apply axial force to the tension element for withdrawing the grasper with mechanical advantage.
In another aspect, the invention features an operating handle for a medical instrument. The operating handle includes a control element extending along an axis and an operating assembly which is coupled to the control element. The operating assembly includes a manual actuator directly connected to the control element for moving the control element axially and for rotating the control element about the axis to a desired orientation. The operating assembly also includes a mechanical actuator coupled to the control element through a selective engagement member, such that the mechanical actuator is actuatable to move the control element axially with mechanical advantage and without rotation from the desired orientation.
In another aspect, the invention features an instrument for grasping or crushing a calculus. The instrument includes an elongate catheter sheath that extends along an axis from a proximal end to a distal end and is sized for insertion into the organ. A basket-form calculus grasper is formed of flexible wires arranged to be extended from and withdrawn within the distal end of the catheter sheath such that, when extended from the distal end of the sheath, the wires are spaced to permit passage of the calculus and when withdrawn at least partially into the catheter sheath, the wires collapse in a manner to capture the calculus. A tension element is coupled to the grasper. A handle is provided at the proximal end of the catheter sheath that receives the tension element and houses an operating assembly to apply axial force to the tension element for extending or withdrawing the grasper from the distal end of the sheath and for rotating the grasper about the axis. The operating assembly includes a manual control knob directly connected to the tension element and arranged for applying axial force to the tension element for extending the grasper from the distal end of the sheath and for imparting rotational motion to the tension element for rotating the grasper about the instrument axis to a desired orientation. A mechanical actuator is arranged to apply axial force to the tension element for withdrawing the grasper with mechanical advantage. The mechanical actuator includes an engaging piece cooperatively constructed with the tension element to bear on the tension element to apply axial force when the tension element is in various rotational states.
Embodiments may include one or more of the following features. The tension element has a substantially smooth cylindrical surface and the engaging piece is a jam element arranged to bear on the surface. The instrument includes a ratchet mechanism for selectively preventing extension of the basket. The ratchet mechanism includes a ratchet jam element arranged to bear on the surface. The mechanical actuator includes a failure element that fails mechanically in response to excessive tension applied to the tension element while permitting actuation of the grasper using the manual control knob. The failure element is a hinge. The hinge is a weakened portion on the mechanical actuator jam element.
Embodiments may include one or more of the following features. The tension element has an outer engaging surface along a segment corresponding to a desired range of rotation and the mechanical actuator includes a complementary engaging element for applying axial withdrawing force. The outer engaging surface and the engaging element are cooperatively constructed to permit the engaging element to apply the axial force to the tension element with the tension element rotationally oriented within the range. The outer engaging surface is a substantially smooth cylindrical surface. The engaging element is a jam element. The jam element is biased in a non-engaging configuration to permit manual operation of the basket using the manual actuator without interference from the mechanical actuator and the jam element can be operated against the bias to engage the tension element for applying axial force to the tension element with mechanical advantage. The jam element is operated through a trigger.
Embodiments may also include one or more of the following features. The instrument includes a ratchet mechanism for preventing extension of the basket. The ratchet mechanism includes an engaging piece cooperatively constructed with the tension element to permit the engaging piece to engage the tension element with the tension element rotationally oriented within the range. The ratchet engaging piece is a ratchet jam element. The ratchet jam element can be operated to a non-engaging configuration to permit operation using the manual control without interference from the ratchet mechanism.
Embodiments may also include one or more of the following features. The manual actuator is actuatable to apply axial force to the tension element for extending and withdrawing the grasper. The catheter sheath is sized to pass through an endoscope. The device includes a fluid port in communication with the catheter sheath. The control element is extended and withdrawn relative to a sheath.
In another aspect, the invention features a method of grasping an object in a body. The method includes providing a medical instrument having an instrument axis and including a grasper actuatable between an open and closed condition. The medical instrument includes an operating mechanism for actuating the grasper alternatively with mechanical advantage or without mechanical advantage and for rotating the grasper about the axis. The grasper is positioned in proximity to the object. The grasper is actuated to open the grasper. The grasper is rotated to a desired orientation and manipulated about the object. The grasper is actuated with mechanical advantage to close the grasper.
Embodiments may also include one or more of the following features. The grasper is actuated with mechanical advantage without rotation of the grasper from the desired orientation. The device is delivered through an endoscope. The object is a calculus.
Embodiments of the invention may provide one or more of the following advantages. Embodiments of the device may be operated to simply grasp, as well as to grasp and crush a calculus. For calculus grasping, the basket can be opened, rotated, and closed manually, without mechanical advantage or interference from a mechanical operating assembly, which improves the tactile feedback to the user and makes the grasping operations easier. For calculus crushing, the basket can be closed with mechanical advantage to apply large collapsing forces. The crushing operation can be conducted without changing the rotational orientation of the basket. Accordingly, calculus treatment, with or without crushing, can be accomplished quickly, even in cases where stones are positioned in a manner which would make capture difficult without basket rotation. In addition, the operating assembly has a mechanically-efficient, low-cost design that is preassembled and permits single-use embodiments, i.e. they can be disposed after a procedure. The operating mechanism may be configured for one-handed crushing operation.
Further aspects, features, and advantages follow.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
We first briefly described the drawings.
DRAWINGS
FIG. 1 is a side view of an instrument for grasping or crushing a calculus;
FIGS. 2-2c are cross-sectional side views illustrating the structure and use of the instrument in FIG. 1;
FIG. 3 is a cross-sectional view of a catheter body for use with the instrument in FIG. 1;
FIG. 4 is a side-view of a basket and tension wire arrangement.
FIG. 5 is a perspective view of a jam element of the operating assembly, while FIG. 5a illustrates use of the jam element in FIG. 5.
DESCRIPTION
Referring to FIG. 1, in an embodiment, an instrument 10 for removing intact or crushing a calculus includes a handle portion 12, a catheter portion 14, and a grasper portion 16. The grasper portion 16 is a basket 18 formed of resilient wires 18a, 18b, 18c, (three of four wires shown) which, when extended from the catheter portion 14, spring outwardly to provide open space between the wires through which a calculus can pass. When the grasper 16 is withdrawn into the catheter portion 14, the wires collapse about the calculus.
The basket 18 is controlled through an operating assembly housed in the handle portion 12. The operating assembly includes a manual control knob 24, a trigger 32, and a ratchet switch 38. The manual control knob 24 is directly connected to the basket so that when the control knob is extended, retracted (arrow 26), or rotated (arrow 28) about the device axis 30, the basket is extended, retracted (arrow 26'), or rotated (arrow 28') by the same amount without mechanical advantage.
The trigger 32 is coupled to the basket through a mechanism so that it can be actuated (arrow 36) to retract the basket with mechanical advantage, permitting the operator to apply considerable collapsing force to the basket in order to crush a calculus.
The ratchet switch 38 permits selective engagement and disengagement of a ratchet stop. By pulling the ratchet switch (arrow 39), the grasper 16 can be actuated and rotated manually using the control knob 24 without interference from the ratchet (or the mechanism associated with the trigger 32). When the ratchet switch 38 is released, the ratchet becomes engaged to prevent extension of the basket so that successive actuation of the trigger 32 will increase the collapsing force of the basket.
Referring to FIGS. 2-2c, the basket 18 is connected to a tension cable 40 which extends through a catheter sheath 20. At its proximal end, the tension cable 40 is attached to a smooth-surfaced cylindrical handle rod 42 which is coupled to the operating assembly housed within the handle portion 12. The manual control knob 24 is connected to the proximal end of the handle rod 42. The retracting key 48 and the ratchet switch 38 are constructed to bear on the smooth-surfaced handle rod to control its motion regardless of the rotational orientation of the rod and, hence, the basket.
The ratchet switch 38 and retracting key 48 are jam elements that have an aperture through which the handle rod 42 can pass with slight clearance. When the keys are oriented at a slight angle with respect to the axis of the handle rod 42, they bear on and grip the handle rod 42. The switch 38 and retractor key 48 are biased in preferential orientations by springs 46, 50, respectively. The ratchet switch 38 is biased to grip the handle rod 42, thus preventing extension or rotation (but permitting withdrawal). The retractor key 48 is biased such that it does not substantially frictionally grip the handle rod 42 and is tilted into gripping condition by actuation of trigger 32.
The trigger 32 pivots about a pin 60 and includes an eccentric cam surface 64. As the trigger 32 is actuated, the cam surface 64 bears on the retractor key 48, causing the retractor key to tilt slightly and grip the handle rod 42 with substantial friction. As the trigger is actuated further, the handle rod 42 and the basket 18 are pulled into the sheath with a 4:1 mechanical advantage from the operator's hand to the force applied to the basket. When the trigger 32 is released, spring 50 causes the retractor key 48 to return to the untilted, non-gripping condition and slides the retractor key forward along the handle rod 42 which at the same time pushes the trigger 32 to its original condition. Forward motion of the handle rod 42 and the basket is prevented by the ratchet key 38 which maintains grip on the handle rod 42. Accordingly, by actuating the trigger 32 a number of times, the basket 18 is pulled further into the sheath 20 which increases the collapsing force of the basket wires which crush the calculus.
Referring particularly to FIGS. 2 and 2a, the device is delivered through an endoscope (not shown) into a body cavity 23 with the basket 18 retracted within the sheath 20 (FIG. 2). The distal end of the catheter sheath 20 is located in the region of a calculus 56 and the ratchet switch 38 is pulled proximally (arrow 39), which frees it from the gripping relationship with the handle rod 42 (FIG. 2a). The basket 18 is then projected from the end of the sheath by pushing the manual control knob 24 (arrow 52) causing the basket wires to spread. The basket 18 can be rotated (arrow 50) about the device axis using the control knob 24 to capture the calculus 56 between the wires.
Referring particularly to FIG. 2b, the basket 18 can then be at least partially withdrawn into the sheath 20 by pulling control knob 24 proximally (arrow 58). The basket wires thus collapse about the calculus 56. In cases where the calculus is smaller than the outer diameter of the endoscope, the basket, grasping the calculus, can be withdrawn with the endoscope and removed from the body.
In cases in which the calculus is larger than the diameter of the endoscope, the operator can use the device to crush the calculus. Calculus crushing can also be useful in cases where multiple stones are present. Stones can be crushed and left in the lumen to be flushed naturally from the body. In this manner, multiple introductions and withdrawals of the device can be avoided. Basket rotation, as provided by the device, also makes it easier to remove a crushed stone from the basket while the device remains inside the body.
Referring as well to FIG. 2c, for a crushing operation, the user withdraws the manual control knob 24 to collapse the basket wires tightly about the calculus 56. The operator then releases the ratchet switch 38 (arrow 41) which causes the switch to be biased by the spring 46 into the gripping orientation, preventing the basket from being extended. The calculus can be crushed by applying additional collapsing force to the basket using the trigger 32.
Referring to FIG. 3, in a particular embodiment, the catheter sheath 20 is made of a stainless steel coil 70 that is covered by fluorothylene polymer (FEP) heat shrink, which enhances lubricity to protect the interior of the endoscope during device delivery. The end of the coil includes a stainless steel tip 72 against which the basket wires bear as they are retracted. A low friction PTFE polymer tube (not shown) is provided inside the coil to enhance lubricity during high tension stone-crushing with the catheter around a tight bend. The proximal end of the sheath 20 includes a luer t-fitting 74 with a port 76 through which fluid can be injected. Referring as well to FIG. 1, the handle portion 12 includes an injection port 22 that communicates with the t-fitting in a manner that fluid, such as saline or contrast, can be delivered through the catheter portion to flow from the distal end of the catheter 20. A piece of heat shrink tubing 78 is provided about the proximal portion of the sheath to provide a fluid-tight seal. The catheter sheath 20 has a length of about 180 cm, an outer diameter of about 2.7 mm, and an inner diameter of about 1.7 mm. This embodiment is sized to pass through a 3.2 or 2.8 mm diameter endoscope channel.
Referring to FIG. 4, the tension cable 40 is a 4×7 stainless steel cabled wire. A short (2-3 mm) stainless steel canula 82 is provided over the tension cable and soldered to keep the wires from unraveling. Distal of the canula 82, four 1×7 cables are separated to form the basket wires. The wires are plasma welded together at their distal ends inside a stainless steel tip 84. The proximal end of the cabled wire 80 includes a canula 86 which is slipped onto the cable, held in place with solder (applied through slits 87) and welded. The basket 18 is connected to the handle rod 42 (stainless steel) by drilling a lumen in the distal end of the handle rod, inserting the proximal end of the cable, and plasma welding.
The handle body and trigger are made of injection molded plastic in a clam-shell configuration. The ratchet key 38 and the retractor key 48 are formed of stainless steel (17-4) with a circular aperture having a diameter of 0.25 inch. The outer diameter of the handle rod is about 0.249 inch.
Referring to FIGS. 5 and 5a, in embodiments, the retractor key 48 can provide a tension limiting feature that prevents excessive tension from being placed on the basket, the wire, or the handle rod. The tension limiting feature is provided by the shape of the ratchet key 48, which includes an opening 90, through which the handle rod extends, and a narrow region 92 that bends at a predetermined stress.
Referring to FIG. 5a, as the assembly reaches the tension limit, the retracting key 48 bends at the narrow region into a different shape. In this shape, the trigger engages the retractor key for only approximately the last 20% of its stroke. The free motion of the trigger for most of the stroke indicates to the user that a hard calculus beyond the capability of the device has been encountered. The physician can continue to use the trigger over the last 20% of the stroke, but the shape of the key after bending limits the stroke of the handle rod so that further retraction is not possible and the tension limit cannot be exceeded. If the stroke reduces, signaling that a very hard calculus is present, the user can release the tension by pulling the trigger key 38. The control knob 24 can be used to project the basket from the sheath to disengage the calculus. Also, the user may, with the knob 24, rotate the basket to seek a more favorable orientation and the crushing operation can be attempted again. If the calculus cannot be crushed in this manner, the basket is disengaged from the calculus and the entire device can be removed from the body without disassembly. The patient may then be treated by other methods.
Other embodiments include mechanical advantage retraction mechanisms that provide greater or less than the 4 to 1 mechanical advantage provided by the trigger arrangement described above. For example, the rod may have a roughened outer surface or morphology that is complementary to engaging pieces that control rod motion. The device can be sized and constructed for use in organs besides the biliary tree. For example, the device can be used in other organs of the gastrointestinal tract. The operating assembly can be adapted for use with other types of graspers.
Still further embodiments are within the following claims.
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Grasping an object, e.g., a calculus in the biliary tract, using a grasper, such as a basket, that can be opened and closed without mechanical advantage and also rotated about the device axis to make it easier to capture the object. The basket can then be closed further with mechanical advantage to crush the object.
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CROSS-REFERENCES
The present application is a continuation in part application of application Ser. No. 08/493,849 filed Jun. 20, 1995, entitled "Front Roller Feeder" that is currently pending, now U.S. Pat. No. 5,605,106.
BACKGROUND OF THE INVENTION
The Union Special Corporation Model 35800 High Speed Feed Off-The-Arm machine is used to produce felled seams on medium to heavy weight denim. This machine is used to produce either double felled or single fell seams. The Model 35800 High Speed Feed Off-The-Arm machine has three needles and three loopers and produces three rows of Type 401 stitches. In addition to the conventional feed dogs and presser foot, this machine includes a driven upper feed roller that engages the upper surface of the fabric behind the stitch forming area and functions to pull the fabric in the direction of feed.
When using this machine to produce a double felled seam along the inseam of denim jeans or for piecing sleeves on denim jackets, a feller assembly is located forward of the stitch forming area to assist the operator in interlapping the marginal edges of the upper and lower plies of fabric.
Denim is made from large yarns and is a "twill" type fabric that easily stretches. This characteristic of denim is the reason that jeans are so comfortable to wear. However, this characteristic of denim also makes denim difficult to sew. When sewing denim fabric the fabric should be in its natural relaxed state rather than in a stretched state. If denim is sewn when it is stretched, the seam will become distorted when the fabric attempts to return to its relaxed state.
When producing inseams on denim jeans, the operator must use her or his fingers to manually push the interlaped fabric into the stitch forming area of the sewing machine. This is necessary to assure that the fabric is being stitched in its natural relaxed state and also to assure even margins along the felled seam. The production of acceptable inseams on denim jeans requires a highly skilled operator who is experienced and who has been extensively trained. When producing the inseam on denim jeans when the cross seam is encountered, the number of fabric plies abruptly quadruples. A double felled seam has four plies of material, however, when four double felled seams converge at a point, as occurs at the crouch of a pair of denim jeans, sixteen plies of material must be sewn together. Pushing the fabric into the stitch forming area when cross seams are encountered is particularly stressful on the fingers and hands of the sewing machine operator. As the cross seam approaches the stitch forming area, there is an increase in the amount of material and the balkiness of the material being advanced by the sewing machine feed mechanism. It is difficult to pull this increases amount of bulky material under and through the presser foot. As a result the forward speed of the material is slowed which causes the stitch length to be shortened. When sewing denim jeans it is usual that eight to ten stitches immediately preceding the cross seam will be shorter than standard stitch length. This is considered undesirable since not only does it effect the appearance of the garment but it further increases the bulk and stiffness of the garment in this critical area. Furthermore, if the operator must concentrate her or his attention and efforts on pushing the fabric into the stitch forming area, their attention to other facets of the operation is diminished and it becomes more likely that the fabric will not be properly fed into the feller attachment.
For the foregoing reasons, there is a need for a machine that can relieve the sewing machine operator of the manual and stressful task of pushing the folded fabric into the stitching area of the sewing machine and for the elimination of the stitch shortening that occurs immediately prior to the cross seam.
SUMMARY OF THE INVENTION
The present invention is directed to an apparatus that satisfies the need for an apparatus that will feed the fabric that has been folded to form a felled seam to the stitch forming mechanism in its natural relaxed state and to assure that the margins along the seam will be even and uniform. The apparatus consists of a sewing machine including a sewing head and a work support portion in combination with a puller feed roller disposed to the rear of the stitch forming mechanism and a synchronized driven feed roller disposed forward of the stitch forming mechanism.
The invention also consists of an upper front feed mechanism that is operatively associated with the presser foot for a sewing machine of the type that includes a lower feed mechanism that is operatively associated with the presser foot that will cooperate to feed the fabric to the stitch forming mechanism in a relaxed unstretched condition.
Another aspect of this invention consist of an apparatus including a sewing head and a work support portion in combination with a puller feed roller disposed to the rear of the stitch forming mechanism that is biased downwardly and a driven feed roller disposed forward of the stitch forming mechanism that is biased downwardly independently of the rear puller feed roller.
Still another aspect of this invention consists of a cooperative relationship between a front roller feeder and the presser foot of the sewing machine that will prevent the work product from riding up from the work surface with the front roller feeder.
Yet another aspect of this invention consists of a front roller feeder that will be raised up from the work surface along with the presser foot.
The invention further consist of a front puller mechanism that pushes the material into the sewing area that cooperates with the rear material pull mechanism which together eliminates the stitch shortening that usually occurs as the stitching approached the cross seams.
The invention also consist of the use of a differential feed mechanism that is located below the front roller to vary the forward feed velocity of the lower ply of material relative to the upper ply which allow the machine operator to align the cross seams such that they match and control the top and bottom ply such that they come out even.
One edge guide embodiment is mounted on the bracket for the forward feed roller such that the edge guide is adjacent to the forward feed roller when the forward feed roller is operative and swings forward toward the material folding device when the forward feed roller is raised where it functions-as an edge guide for the material as it is being loaded into the folder and under the front feed roller.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the upper head portion of a High Speed Feed Off-The-Arm sewing machine having an embodiment of this invention mounted thereon.
FIG. 1A is an exploded view of a feller assembly of the type that could be used with the sewing machine illustrated in FIG. 1.
FIG. 2 is a rear perspective view of a portion of the mechanism of this invention in which the rear guidance system and rear spring pressure system mechanisms are clearly visible.
FIG. 3 is a side perspective view of a portion of the mechanism of this invention in which the manual lift for the rear shaft and the main bracket are clearly visible.
FIG. 4 is an isolated perspective view of the real lift handle for the rear shaft and the main bracket.
FIG. 5 is a front perspective view of a portion of the mechanism of this invention in which the presser foot bar, presser foot holder, presser foot and throat plate are clearly visible.
FIG. 6 is a top-front perspective view of a portion of the mechanism of this invention in which the front and rear rollers are clearly visible.
FIG. 6A is a bottom-front perspective view of a portion of the mechanism seen in FIG. 6, with the drive belt removed.
FIG. 7 is a front perspective view of a portion of the mechanism of this invention in which the height adjusting brackets are clearly visible.
FIG. 8 is a front perspective view of a portion of the mechanism of this invention in which the manual spring for the front roller is clearly visible.
FIG. 9 is a rear perspective view of a portion of the mechanism of this invention in which the manual lift cable assembly is clearly visible.
FIG. 10 is a front perspective view of a portion of the mechanism of this invention in which the miter gear case for the rear roller drive is clearly visible.
FIG. 11 is a front perspective view of a portion of the mechanism of this invention in which the throat plate, presser foot, rear roller and front roller are clearly visible.
FIG. 12 is a top perspective view of a portion of the mechanism of this invention including the adjustable edge guide embodiment.
FIG. 13 is a front perspective view of a portion of the mechanism of this invention including the adjustable edge guide embodiment.
FIG. 14 is a front perspective view of a portion of the mechanism of this invention including the front roller bracket and the adjustable edge guide embodiment.
FIG. 15 is a rear perspective view of a portion of the mechanism of this invention in which the air lift mechanism for the main bracket is shown.
FIG. 16 is a front perspective view of a portion of the mechanism of this invention in which the presser foot bar, presser foot holder, presser foot, throat plate and the presser bar air lift mechanism are clearly visible.
FIG. 17 is a rear perspective view of a portion of the mechanism of this invention in which the front air pressure lift mechanism is clearly visible.
FIG. 18 is an isolated perspective view from above of another edge guide embodiment that is shown in the operative position adjacent to the front feeder roller and the threat plate.
FIG. 19 is an isolated perspective view of the edge guide embodiment illustrated in FIG. 18 shown in the operative position adjacent to the front feeder roller.
FIG. 20 is an isolated perspective view of the edge guide embodiment illustrated in FIGS. 18-19 shown in the operative position adjacent to the front feeder roller without the throat plate.
FIG. 21 is an isolated perspective view of the edge guide embodiment illustrated in FIGS. 18-20 shown with the front roller bracket raised and the edge guide swung forward.
FIG. 22 is an exploded view of an embodiment of a differential feed dog mechanism.
FIG. 23 is a perspective view of a sewing machine of the type that is used with this invention in which the control for the differential feed is shown.
FIG. 24 is an issolated side view of the embodiment including the differential feed dog showing the relationship between the differential feed dog and the front roller.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a perspective view of the upper head portion 20 of a High Speed Feed Off-The-Arm sewing machine 2 including a lower arm 3 and reciprocating needles 8 that cooperate with loopers to form rows of 401 type stitches. An embodiment of the front roller feeder 30 of this invention is included in FIG. 1 to illustrate how it is mounted on the sewing machine 2.
FIG. 1A is an exploded view of a feller assembly 4 for a double felled seam of the type that could be used with the sewing machine 2 illustrated in FIG. 1. The feller assembly 4 includes an upper scroll 5, a lower scroll 6 and a base or work supporting surface 7. The assembled feller assembly 4 is mounted on the lower arm 3 of the sewing machine 2 forward of the throat plate 180.
FIG. 2 is a rear perspective view of the upper head 20 and top plate 22 of the Feed Off-The-Arm sewing machine 2. An aperture 23 in the top plate 22 slidingly receives the rear shaft 32 that functions to raise and lower the main bracket 34 of the front roller feeder 30. The bottom end of rear shaft 32 is connected to the main bracket 34 by set screws 35. A rear guide finger 36, having a pair of machined guide surfaces 38 formed thereon, is secured to the rear shaft 32 by set screws 37. Down pressure is exerted on the rear guide finger 36 by a spring (not shown) that is concentric with shaft 32. The pressure exerted by the spring can be adjusted by the knob 41.
A rear guide block 24 is secured to the lower portion of the upper head 20. The bolt holes 25 for connecting the rear guide block 24 to the lower portion of the upper head 20 are visible in FIG. 15. A vertical bore 33 is formed in the rear guide block 24 that slidably receives the rear shaft 32. A horizontal bore 39 is formed in the rear guide block 24 that intersects with the vertical bore 33. An oil wick 21 is provided in the horizontal bore 39 that functions to lubricate the sliding surfaces of the rear shaft 32 and the vertical bore 33. A support block 26 is secured to the rear guide block 24 and a pair of rear guide thrust blocks 28 are secured to the support block 26 by screws 29.
The rear guide thrust blocks 28 have machined edges 27 that engage the machined guide surfaces 38 of the rear guide finger 36 to thus provide precision guidance for the front roller feeder 30 as it is raised and lowered with the rear shaft 32. The rear guide thrust block 28 can be adjusted on the support blocks 26 through the screws 29. Horizontal bores 10 are formed in the rear guide thrust blocks that communicate with the machined edges 27. An oil wick 11 is provided in each of the bores 10 to provide lubrication to the sliding machined edges 27 and guide surfaces 38. If the rear guide thrust blocks 28 become worn it is a simple and inexpensive task to replace them.
Referring now to FIGS. 3 and 4, a manual lift handle 40 is pivotally mounted on the rear guide block 24 by a screw 43. The lift handle 40 has a gripping portion 42 at one end and a lever 44 at the other end. The rear guide finger 36 has a lift pin 31 protruding from it that is located to be engaged by a cam surface 45 formed on the upper edge of the rear lever 44. The cam surface has a depression 47 at the end portion of the lever 44 that is shaped to receive and contain the lift pin 31 to thus support the back end of the front roller feeder 30, including the roller 50, in the full up position. The lift handle 40 is biased by spring 46 that causes the handle 40 to pivot about screw 43 in the clockwise direction as seen in FIG. 3. As best seen in FIG. 4, the lever 44 of the lift handle 40 has a stop pin 49 that carries a bumper 48. The clockwise rotation of the lift handle 40 is stopped when the bumper 48 engages the upper surface of the rear guide block 24.
During sewing operation the main bracket 34 raises and falls slightly in response to the thickness of the fabric that the rear roller 50 is encountering. Thus, there is continuous movement between the engaging surfaces 27, 38 and 32, 33 during the sewing operation. These surfaces are lubricated by the oil wicks 11 and 21 to facilitate this movement and minimize wear on the parts.
When it is desired to lift the main bracket 34 off the work piece, the operator grasps the manual lift handle 40 by the gripping portion 42 and pivots it counterclockwise against the action of spring 46. When the lift pin 31 enters the depression 47 in the lever 44 the operator can release the lift handle and the main bracket 34 will be retained in the raised position.
The rear roller 50 is secured to a rear roller shaft 52 that is journaled for rotation in the hubs 54 and 56 of the main bracket 34 (see FIG. 15). A set of needle bearings is provided in hubs 54 and 56 to minimize frictional resistance to the rotation of roller shaft 52.
A front roller bracket 60, having a generally rectangular shape, includes hubs 62 and 64 that are journaled on the rear roller shaft 52. Hubs 62 and 64 are integral with the front roller bracket 60. A rear pulley 66, see FIG. 6, is secured to rear roller shaft 52 between the rear roller 50 and the hub 64. A thrust collar 68 is secured to one end of the roller shaft 52 and a driven miter gear 70 to its other end.
A vertically orientated hub 72 is carried by the main bracket 34 for journaling a drive shaft 74. A set of needle bearings is carried by the hub 72 for minimizing the friction in this journal. Thrust collars 76 are provided to maintain the drive shaft 74 in the hub 72. A drive miter gear 78 is carried by the lower end of drive shaft 74. Drive miter gear 78 meshes with the driven miter gear 70 and transmits rotary motion to roller shaft 52.
As seen in FIG. 10, a front cover 73 and a rear cover 75 are provided for the miter gears 70 and 78. The covers 73 and 75 are secured to the main bracket 34 by screws 77 that are threaded into threaded bores 79 in the main bracket 34. The preferred embodiment includes a one piece plastic cover for the miter gears 70 and 78.
The front roller bracket 60 (see FIG. 6 and 6A) includes a pair of hubs 82 and 84 at its forward end in which is journaled a front roller shaft 80. The hubs 82 and 84 have sets of needle bearings to minimize friction in these journals. A front roller 86 and a front pulley 88 are secured to front roller shaft 80 for rotation therewith. The front pulley 88 is aligned with rear pulley 66 and a drive belt 90 extends over the aligned pulleys 88 and 66 such that the rotary motion of rear roller shaft 52 is transferred to the front roller shaft 80. In the preferred embodiment the pulleys 66, 88 and the belt 90 are of the sprocket type that have grooves and ridges on their engaging surfaces. This sprocket type drive not only provides a more positive drive connection between the pulleys and the belt, but also ensures that the front roller 86 and rear roller 50 are synchronized.
The front roller bracket 60 has an inclined U-shaped portion 92, that includes a hub 94, at its forward end. As best seen in FIGS. 2 and 8 a hub 98 having a bracket 96 that has three holes 97 formed therein is mounted by bolts (not shown) in three bolt holes (not shown) that are formed in the upper head 20. As best seen in FIG. 2 an internally threaded spring pivot bushing 95 is housed in the hub 94. An elongated compression rod 93 (see FIG. 8) having a knurled knob 87 and a threaded portion 91 is threaded through the internally threaded spring pivot bushing 95. The compression rod 93 includes a guide rod portion 89 that is of smaller diameter than the threaded portion 91. A shoulder 85 is formed on the compression rod 93 at the intersection of the threaded portion 91 and the guide rod portion 89 that functions as a thrust surface for a spring 108. A hollow guide tube 100 slidingly receives the lower end of the guide rod 89. The lower end of the hollow guide tube 100 extends into the hub 94. A thrust washer 102 with an underlaying neoprene washer 104 are received over the hollow guide tube and engage a shoulder 105 formed by the upper annular edge of the hub 94. An annular groove 101 is formed in the hollow guide tube that receives a crescent ring 106 that functions to retain the thrust washer 102 and underlaying neoprene washer 104 in place. The lower end of the spring 108 engages the thrust washer 102 to thus provide an adjustable downward pressure on the forward portion of the front roller bracket 60.
The operator can adjust the tension on spring 108 by grasping the knurled knob 87 of the compression rod 93 and turning it one way or the other. When the compression rod 93 is rotated it is threaded up or down through the internally threaded spring pivot bushing which causes the shoulder 85 of the compression rod 93 to move toward or away from the shoulder 105 of the hub 94. This causes the spring 108 to compress or expand and adjusts the downward pressure on the front roller bracket 60. The spring pivot bushing 95 can oscillate about its axis within the hub 98 which is necessary to accommodate vertical movement of the front roller 86, for example, when the front roller encounters and rides up on a cross seam. This allows the front roller 86 to elevate and walk over the cross seam when it is encountered while continuing to provide positive feed to the work material. This positive pushing of the work material has eliminated the undesirable stitch shortening, that occurs in the eight to ten stitches before going over the cross seam, in the prior art machines. In this situation if the spring pivot bushing 95 was stationary and could not rotate about its axis the system would likely bind.
There is illustrated in FIG. 7 the height adjustment mechanism for the front roller feed. A first height adjustment bracket 120 having a first vertically extending leg 122, a second vertically extending leg 124 and a connecting horizontal section 126 is secured to the front roller bracket by screws 128. A vertically extending slot 130 is formed in the first vertically extending leg 122. The screws 128 extend through slot 130 and are threaded into threaded bores 132 (see FIG. 2) formed in the front roller bracket 60. A nylon bumper 134 is secured to the upper portion of the second vertically extending leg 124. The slot 130 permits the height adjustment bracket 120 to be secured to the front roller bracket 60 within an adjustment range such that the distance between the nylon bumper 134 and the front roller bracket 60 can be varied depending upon conditions. A second height adjustment bracket 136 is secured to the upper head 20 in the general area above the location of the first height adjustment bracket 120 by screws 137. The second height adjustment bracket 136 includes a tab 138 having a horizontal upper surface that underlies the nylon bumper 134. When the nylon bumper 134 engages the horizontal upper surface of the tab 138, downward movement of the front roller bracket 60 is stopped. The position where downward movement of the front roller bracket 60 is stopped can be adjusted through the slot 130 and screws 128.
There is shown in FIG. 9 the manual lift cable assembly 140 for the front roller feed. The manual lift cable assembly 140 includes a flexible cable 142 contained in a case or shield 143 of the Bowden conduit type. The shield 143 is secured to the head 20 of the sewing machine by mounting clips 144. The upper mounting clip 144 is secured to the head 20 by one of the bolts that secure the spring pivot bracket 96 to the head 20. The lower clip 144 is secured by a screw (not shown) to the second height adjustment bracket 136. The upper end of the flexible cable 142 is connected to an arm 146 of a the lift lever bell crank 148 that is secured to and pivots with pivot rod 149. The pivot rod 149 is journaled in an opening 163 formed in the head 20. The other arm 147 of the lever 148 is connected in a conventional manner to the presser bar lift mechanism. The lower end of the flexible cable 142 is connected to the U-shaped portion 92 of the front roller bracket 60. Thus, when the presser bar lift mechanism is engaged to, for example, raise the presser bar 160, a corresponding movement is transmitted to the forward end of the front roller bracket through the flexible cable 142 and the front roller 86 to be lifted off the work product. When the presser bar 160 is lowered, the lever 148 is pivoted in the opposite direction which allows the front end of the front roller bracket 60 to descend until the nylon bumper 134 encounters the tab 138 which stops its downward movement at the preselected elevation.
The presser bar 160 and presser foot 162 are illustrated in FIG. 5. The presser bar 160 is a conventional presser bar that is mounted for vertical reciprocating movement in the head 20 by bushings such as bushing 161. A presser bar lift and guide 164 is secured to the presser bar by a screw 165. A presser spring (not shown) engages the upper surface of the lift and guide 164 and a shoulder 166 to thus exert a downward pressure on the presser foot 162. A knurled knob 168 can be turned by the operator to vary the intensity of the spring pressure. Adjustable guide plates 169 are provided that cooperate with the presser bar lift and guide 169 to insure smooth reciprocal movement of the presser bar 160. As is well known in the sewing machine art, one end of a lift link (not shown) is linked to the lift and guide 164 by screw 167 and the other end of the lift link is linked to the presser bar lift lever that is carried by a pivot rod 149 that is journaled in opening 163. The lift lever bell crank 148 is secured to the other end of pivot rod 149. A presser foot holder 170 is secured to the lower end of the presser bar 160 by a set screw 172. The presser foot holder is in the form of a two tine fork that is pivotally connected to the presser foot 162 at the extremities of the tines. The presser foot 162 includes three upwardly inclined toe sections that are separated by slots 173 and 174. The presser foot 162 also has needle opening 176 formed therein. The presser foot 162 is biased downwardly toward the throat plate 180. The throat plate 180 includes a raised ridge 182 that extends in the direction of stitch formation and a plurality of slots 183 through which the feed dog elements project.
There is shown in FIG. 11 another embodiment of a presser foot, designated 184, that includes an integral edge guide 186 that functions to guide the folded edge of the top ply of material. Edge guide 186 will ensure that the margin of material between the edge and the adjacent row of stitches remains uniform. This embodiment of the presser foot will produce a stitch with a fixed width margin of material between the folded edge of the top ply and the row of stitches. The presser foot must be replaced with a different presser foot, having the edge guide 186 at a different location relative to the needle holes, if a stitch having a margin of a different width is desired. In FIG. 11 the rear roller 50 and front roller 86 have been included to illustrated their relationship to the presser foot. It should be noted that, in the embodiment of the presser foot 162 shown in FIG. 5 as well as the embodiment of the presser foot 184 shown in FIG. 11, the two sections of front roller 86 are located within the slots 173 and 174 formed in the presser foot and one of the presser foot toes is located between the sections of the front roller 86. This relationship is best illustrated in FIG. 6A which is a bottom view of the presser foot 162. This is an important relationship of this invention since the top ply of material has a tendency to stick to the front roller 86 and ride up with it. The presence of the presser foot toe between the sections of the front roller 86 functions to strip the top ply of the work product off the front roller and cause it to feed under the presser foot as desired. FIG. 6A also illustrates that the rear roller 50 is in a position relative to the presser foot 162 to exercise control over the work product as soon as control is lost by the presser foot.
FIGS. 12, 13 and 14 disclose an embodiment in which the edge guide 220 for the top ply of work product is adjustable laterally so that the margin of material between the folded edge and the row of stitches can be varied without the need to replace the presser foot. The adjustable edge guide 220 is adjustable left to right relative to the line of stitching to vary the width of the margin between the folded edge of the upper ply of material and the row of stitches. The mounting mechanism that carries the adjustable edge guide 220 is mounted in holes 240, 242 and 244 (see FIG. 6A) formed in the front roller bracket 60. Through its mounting mechanism the adjustable edge guide 220 is independently spring loaded so that it can contact the work material and rise up and down as it crosses over seams.
The edge guide 220 has an integral edge guide mounting pin 222 that extends into an opening 223, formed in the guide arm 224. The edge guide mounting pin 222 can slide longitudinally of its axis in opening 223 and can be locked in a longitudinal adjusted position by a screw 225. This longitudinal adjustment and locking in a selected location allows the edge guide 220 to be adjusted left or right of the row of stitches and thus to establish the width of the margin. This adjustable feature allows the margin to be varied without replacing the presser foot 162. The guide arm 224 has a pivot shaft 226 at its rear end that extends through hole 240 that is formed in the front roller bracket 60 (see FIG. 6A). A washer 227 is carried by pivot shaft 226 for engagement with the surface of the front roller bracket 60 to provide free pivot movement. The pivot shaft 226 allows the edge guide 220 to pivot up and down as is required for it to cross over seams and the like. A front spring finger 232 is carried by the portion of the pivot shaft 226 that projects out of hole 240 on a aperture (not shown) formed in the front spring finger 232. The front spring finger 232 includes a downwardly directed arm 233 and a check pin 231 that extends parallel to pivot shaft 226. A hole 246 is formed at the lower extremity of the downwardly directed arm 233 for receiving one end of a spring 248. An edge guide thruster 228 is carried by the pivot shaft outwardly of the front spring finger 232. The edge guide thruster 228 includes an arm 229 that has an aperture formed therein for reception of the check pin 231 of the front spring finger 232. The edge guide thruster 228 is secured to the pivot shaft 226 by a screw 230. Thus, the downwardly directed arm 233 of the front spring finger 232 and the arm 229 of the edge guide thruster 228 are fixed to the pivot shaft 226 and pivot therewith. A thrust pin 234 made, for example, of nylon material, having a flat head 235 is carried by hole 242 formed in the front roller bracket 60. The arm 229 of the edge guide thruster 228 is flush with and slides along the flat head 235 of the thrust pin 234. A rear spring finger 236 is secured in the threaded hole 244 formed in the front roller bracket 60 by a screw 237. An opening 247 is formed at the extremity of the rear spring finger 236 for the reception of the other end of spring 248. Spring 248 extends from the rear spring finger 236 to the front spring finger 232 and functions to exert a clockwise torque on pivot shaft 226 and thus, a downward spring pressure on the edge guide 220. The magnitude of this downward spring pressure can be adjusted by adjusting the location of rear spring finger 236 by loosening screw 237 adjusting the location of the rear spring finger 236 and securing it in adjusted position by the screw 237.
FIG. 15 discloses the preferred embodiment for controlling the rear shaft 32. In this embodiment a double acting air cylinder 200 is connected to the upper end of shaft 32 above the top plate 22. Pressurized air can be supplied to either side of the piston of air cylinder 200. When air under pressure is supplied to cylinder 200 causing a downward pressure to be applied to the main bracket 34, a spring that performs that task in the manual embodiment is eliminated. When air under pressure is supplied to cylinder 200 causing the main bracket to be lifted up off the work product, the manual lift handle 40 has been eliminated. The sewing machine operator can control the pressurized air that is directed to double acting air cylinder 200.
FIG. 16 discloses the preferred embodiment for raising and lowering the presser bar 160. A double acting air cylinder 202 is connected to the top of the presser bar 160 above the top plate 22. Air cylinder 202 is energized in one direction to raise the presser bar 160 and in the other direction to lower it. The sewing machine operator can control the pressurized air that is directed to double acting air cylinder 202.
FIG. 17 discloses the preferred embodiment for raising the front end of the front roller bracket 60 and the front roller 86. In this embodiment a double acting air cylinder 204 is connected to front air shaft 206. As in the mechanical embodiment that is illustrated in FIG. 8 a pivot bushing 208 is journaled for oscillating motion in the hub 98. The front air shaft 206 extends through a bore formed in the pivot bushing 208 into front air adapter 210. Within the front air adapter 210, the front air shaft 206 is coupled to the piston rod (not shown) of the double acting air cylinder 204. A clamp 212, thrust washer 214 and a neoprene washer 216 are provided at the lower end of the front air shaft 206 to transfer the reciprocating motion of the front air shaft 206 to the U-shaped portion 92 of the front roller bracket 60. In the mechanical embodiment, (see FIG. 8) the front roller spring 108 functions to provide an adjustable pressure in the downward direction on the front roller bracket 60. This function is replaced in the preferred air cylinder embodiment by air cylinder 204. However, in the preferred air cylinder embodiment, the air cylinder 204 also performs the function of raising and lowering the front end of the front roller bracket 60. That function in the mechanical embodiment is performed by the manual lift cable assembly 140 that is illustrated in FIG. 9. The sewing machine operator can control the pressurized air that is directed to double acting air cylinder 204.
An additional edge guide embodiment is illustrated in FIGS. 18 through 21. As best seen in FIG. 19 an edge guide bracket 310 is secured to the left edge of the inclined U-shaped portion 92 of the front roller bracket 60. The bracket 310 has two arms 311 and 312 at right angles to each other. Both of these arms are secured to the inclined. U-shaped portion 92 by bolts that are threaded into the front roller bracket 60 to insure a solid connection. The edge guide bracket 310 also has a hub portion 313 with a bore 314 formed therein. A pivot shaft 316 is rotatably received in the bore 314. The pivot shaft is retained in the bore 314 by a collar 317 on one side and by a thrust washer 318 and spring clip 319 on the other side. Spring clip 319 is snapped into a groove formed in the pivot shaft 316. A coil spring 325 having one end secured in a hole formed in the pivot shaft 316, includes a coil portion 326 that is wrapped around the pivot shaft 316 and an arm portion 327 that extends across the bottom edge of the edge guide bracket 310. A swing arm 330 is secured by a screw 332 to the end portion of pivot shaft 316 that extends beyond the collar 317. The spring 325 causes the swing arm to swing up and toward the front. An edge guide 320 has a groove 322 formed therein that receives the free end of the swing arm 330. The edge guide 320 is secured to the swing arm 330 by a screw 323. The location of the swing arm 330 along the pivot shaft 316 can be adjusted through the screw 332 to thus move the edge guide 320 toward and away from the front feeder roller 86. When the edge guide 320 is in its operative position it is along side of the forward feed roller 86 and immediately above the throat plate 180. The swing arm 330 and edge guide 320 swings forward toward the material folding device when the forward feed roller is raised. While the edge guide 320 is in this forward position it functions as an edge guide for the material as it is being loaded into the folder and forced under the front feed roller. Since the edge guide 320 has maintained its lateral position relative to the front feeder roller 86 the material in the folder will be properly aligned.
Differential feed dogs are utilized for various purposes in a number of sewing operations. A differential feed mechanism for a sewing machine is disclosed for example in U.S. Pat. No. 4,436,045, which patent is hereby included by reference as a part of this disclosure. An embodiment of a differential feed dog mechanism is shown in FIG. 22. The main feed dog 408 is secured to the main feed bar 447 and the differential feed dog 402 is secured to the differential feed bar 441. The vertical movement that is imparted to both the main feed dog 408 and the differential feed dog 402 is the same and can not be changed. However, the horizontal or fore and aft movement of the differential feed dog 402 can be varied such that it is more or less than that of the main feed dog 408. The main feed bar 447 receives its vertical motion from crank mechanism 413 and its horizontal motion is controlled by arm 410. The vertical motion of the main feed bar 447 is transmitted to the differential feed bar 441 by the engagement of a claw 442 on the differential feed bar 441 with flat surfaces 443 on the main feed bar 447. As best seen in FIG. 23, a control 400 is provided on the sewing machine at a location that is convenient to the operator for adjusting the horizontal or fore and aft movement of the differential feed dog 402. This control 400 includes a pivoted arm 410 that can be grasp by the operator. The free end of the arm functions as a pointer that moves over indicia which represents the adjustment level. For example, at the twelve o'clock position the horizontal feed of the differential feed dog 402 is the same as the main feed dog 408, to the right of the twelve o'clock position indicates that the differential feed dog has a greater horizontal feed than the main feed dog 408 and to the left of the twelve o'clock position indicates that the differential feed dog has a smaller horizontal feed than the main feed dog 408. It should be noted that the sewing machine 2 shown in FIG. 23 is of the type that this invention is used with, however a conventions roller feed mechanism is shown in FIG. 23. The pivot arm 410 has a pivoted slide block (not shown) that sets in the slot 436 of bellcrank 434. Thus, adjustment of pivot arm 410 causes the bellcrank 434 to pivot about pivot shaft 435. The other arm of bellcrank 434 is connected through link 437 to lever 439. One end of lever 439 carries a pivoted slide block 431 that slides in slot 432 that is formed in oscillating member 430. The other end of lever 439 is connected through a bushing 444 to the differential feed bar 441. The oscillating member 430 receives its movement from a crank arm that is pivotally connected to collars 429. The crank arm (not shown) as is conventional is driven through an eccentric carried by the main drive shaft of the sewing machine. Through this mechanism adjustment of arm 410 causes slide block 431 to move along slot 432. The position of slide block 431 in slot 432 determines the amount of horizontal movement that will be transmitted to the differential feed dog 402. When the slide block 431 is located in the lower portion of the slot 432 close to pivot shaft 435 the lever arm for imparting motion to lever 439 is small and the amount of horizontal movement imparted to the differential feed dog 402 is correspondingly small. When the slide block 431 is located in the upper portion of the slot 432 the lever arm that imparts motion to lever 439 is large and the horizontal motion imparted to the differential feed dog 402 is accordingly greater.
As seen in FIG. 24 the differential feed dog 402 is located such that it is directly under the front roller 86. These components thus function as a driven upper feed, front roller 86, and a driven lower feed, differential feed dog 402. The stitch length of the differential feed dog 402 is set through the control 400. Usually the control 400 is set to produce the same number of stitch per inch as is being produced by the main feed dog 408. The front roller 86 contacts the top ply of the folded seam and the differential feed dog 402 contacts the bottom ply of the folded seam. Thus, if the amount of travel imparted by the differential feed dog 402 to the lower ply is changed in relation to the travel imparted by the front roller 86 to the upper ply, then the rate of feed of the top and bottom plies will vary. As previously explained by adjusting the arm 410 of the control 400 the amount of differential feed dog 402 travel can be increased or decreased in relation to the travel imparted to the upper ply by the front roller 86.
This feature of the invention is important to enable the operator to match the cross seam of the upper and lower plies. It is important for structural soundness of the garment, the proper fit and the appearance that the cross seams are aligned. This feature of the invention is also important because it permits the operator to match the top and bottom plies to come out even at the finish or end of the seam. In the prior art, both the alignment of the cross seam and matching the top and bottom plies at the finish, are objectives that the operator attempts to achieve by tugging and pulling on the top or bottom ply. In accordance with this invention the operator simply moves the control arm 410 of the control 400 to vary the feed rates between the top and bottom plies so that the cross seam will match and the ends come out even.
While the invention has heretofore been described in detail with particular reference to the illustrated apparatus, it is to be understood that variations, modifications and the use of equivalent mechanisms can be affected without departing from the scope of this invention. It is, therefore, intended that such changes and modifications be covered by the following claims.
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A fabric feed mechanism that includes a forward feed roller located forward of the stitch forming area and a rear feed roller located to the rear of the stitch forming area. The drive to the forward and rear feed rollers is synchronized such that the fabric is fed to the stitch forming instruments in a relaxed and unstretched condition. There is a independently applied downward pressure to forward and rear feed rollers and the forward feed roller is raised along with the presser foot. The front feed roller has sections that are located on opposite sides of the presser foot toe to thus ensure that the top layer of fabric is fed under the presser foot rather than riding up the front roller. A material folding device is located forward of the stitch forming area for folding material to be fed to the stitch forming area. An adjustable edge guide member is mounted on the bracket for the forward feed roller such that the edge guide is adjacent to the forward feed roller when the forward feed roller is operative and swings forward toward the material folding device when the forward feed roller is raised where it functions as an edge guide for the material as it is being loaded into the folder and under the front feed roller. A differential feed mechanism is provided below the front roller which can be adjusted to vary the forward feed velocity of the lower ply of material relative to the upper ply which allow the machine operator to align the cross seams such that they match and control the top and bottom ply such that they come out even.
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FIELD OF THE INVENTION
[0001] This invention relates to a heating apparatus. Specifically, this invention relates to heaters which incorporate a positive temperature coefficient (PTC) element.
BACKGROUND OF THE INVENTION
[0002] Positive temperature coefficient (PTC) materials have been used in heating applications for many years. Upon application of an electric bias to a PTC material, it initially has a low electrical resistance and heats up quickly due to current flow through the material. However, once the PTC material reaches the Curie point, its resistance increases so that it maintains a substantially constant temperature and heat output. This self-regulating characteristic of PTC materials significantly decreases the potential for heating element burnout as well as the need for temperature-regulating electronics, and thus makes these materials attractive for use in heating elements such as those in space heaters, hair dryers, and other applications.
[0003] U.S. Pat. No. 4,654,510 to Umeya et al. describes one type of PTC heating element. Holes formed through the PTC element, parallel to the direction of current flow, provide a pathway for air. The air is heated as it passes through the PTC element.
[0004] U.S. Pat. No. 4,855,570 to Wang discloses another PTC element arrangement where the PTC elements are exposed directly to airflow. The heating unit described by Wang includes a plurality of PTC elements arranged radially between two cylindrical electrodes. The PTC elements are arranged so that their broad surfaces are parallel to air flow through the heating element.
[0005] Other heater designs include heat sinks which receive heat from the PTC elements and transfer it to air passing by and/or through the heat sinks. To increase the convective heat transfer to the air, these heat sinks typically have many holes providing paths for air flow. One such configuration is described in U.S. Pat. No. 4,654,510 to Nakamura et al., in which the heat sinks provide a plurality of fluid pathways for air to flow through. By orienting the fluid pathways in the heat sinks parallel to the broad surfaces of the PTC elements, these heating devices do not require holes through the PTC elements themselves. Additionally, Nakamura utilizes the heat sinks as electrodes which may stabilize current spikes and reduce the likelihood of PTC element burnout.
SUMMARY OF THE INVENTION
[0006] In at least one aspect of the present invention, a heating element utilizing positive temperature coefficient (PTC) elements has sufficient surface area for effective heat transfer as well as the capability to heat a large volume of air without creating a large internal air resistance.
[0007] In another aspect of the present invention, an arrangement of PTC elements in a heating element can be configured to provide the desired heat output and desired heat distribution.
[0008] In another aspect of the present invention, a PTC heating element may be provided where broad surfaces of the PTC element(s) are arranged substantially perpendicular to the direction of airflow.
[0009] In another aspect of the present invention, a PTC heating element may include at least one heat sink and at least one PTC element, configured such that there is sufficient pressure between the PTC element and the heat sink to promote heat transfer and provide sufficient electrical and/or thermal contact between the PTC element and heat sink.
[0010] In another aspect of the present invention, a heating element includes a first heat sink and at least one PTC element thermally coupled to the first heat sink, aligned such that a current direction of the PTC element (i.e., the direction in which current would flow if an electric bias were applied to the heating element) is substantially parallel to a fluid pathway formed by openings in the first heat sink.
[0011] In another aspect of the present invention, a heating element includes a first heat sink and a PTC element thermally coupled to the first heat sink positioned substantially out of a fluid pathway formed by openings in the first heat sink so that a largest surface area of the PTC element is approximately perpendicular to the fluid pathway.
[0012] In another aspect of the present invention, a heating element includes at least one heat sink and a PTC element thermally coupled to the heat sink such that at least 50% of the heat output by the PTC element is transferred to heat sink(s) coupled to the PTC element and arranged so that a largest surface of the PTC element is approximately perpendicular to a fluid pathway formed by opening(s) in the heat sink(s).
[0013] In another aspect of the present invention, a heating element includes first and second heat sinks with openings that form a fluid pathway and a plurality of PTC elements substantially aligned in a single plane such that the current direction of the PTC elements is substantially parallel to one another and the PTC elements are arranged radially inside a circle, where the first and second heat sinks are configured to act as electrodes for the plurality of PTC elements.
[0014] In another aspect of the present invention, a heating element includes a heat sink and at least one PTC element in thermal communication with the heat sink, where a fluid pathway formed by at least one opening in the heat sink first passes either the heat sink or the PTC element and then passes the other.
[0015] In another aspect of the present invention, a heater includes an air circulator to move air through a heating element, where the heating element includes a first heat sink thermally coupled to at least one PTC element, where the PTC element is aligned such that the current direction is substantially parallel to a fluid pathway formed by the first heat sink.
[0016] In another aspect of the present invention, a heating element has a plurality of PTC elements radially arranged within a circle. The radial arrangement includes radial flanges, and at least one radial flange may include one or more PTC elements. In one embodiment, the heat sinks may shield the PTC elements from direct air flow. The heat sinks may also act as electrodes to the PTC elements. If the heat sinks function as electrodes, electrically non-conductive fasteners connecting the heat sinks and PTC elements may be used so as to avoid short circuiting the heat sinks when an electric bias is applied. The fasteners may additionally apply pressure between the plurality of PTC elements and heat sinks.
[0017] These and other features of the present invention will be elucidated through the accompanying drawings and detailed description below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] [0018]FIG. 1 is a perspective exploded view of one embodiment of a heating element in one aspect of the present invention;
[0019] [0019]FIG. 2 is a side view of one embodiment of a heating element in one aspect of the present invention;
[0020] [0020]FIGS. 3 through 11 are top views of different PTC element arrangements according to one aspect of the present invention; and
[0021] [0021]FIG. 12 is a side view of a heater utilizing a PTC heating element in one aspect of the present invention.
DETAILED DESCRIPTION
[0022] A heating element according to aspects of the present invention can be sized and configured for any suitable use. For example, a heating element according to aspects of the invention may be used to heat air in an electric portable space heater, hair dryer, heat gun, etc. Although embodiments are described below in connection with heating air, a heating element in accordance with at least one aspect of the invention may be used to heat any suitable material, whether a gas, liquid or solid. As used herein, the term fluid refers to both gases and liquids.
[0023] [0023]FIG. 1 shows an illustrative embodiment of a heating element 100 that incorporates various aspects of the invention. In this embodiment, the heating element 100 includes a plurality of PTC elements 110 disposed between a pair of heat sinks 120 , although any number of PTC elements 110 and heat sinks 120 , such as one each, may be used. The heat sinks 120 are electrically and thermally coupled to the PTC elements 110 so that electric current and heat may be conducted between them. In this embodiment, the heat sinks 120 have solid portions which electrically and/or thermally contact the PTC elements 110 , as well as openings 140 between the solid portions which enable fluid flow (e.g., air flow) through the heat sinks 120 . Thus, when an electric bias is applied to the heat sinks 120 and/or other electrodes, the resulting current through the PTC elements 110 causes the PTC elements 110 and heat sinks 120 to heat up. In turn, the heat sinks 120 may transfer at least a portion of the heat to air passing through the openings 140 and/or around the heat sinks 120 .
[0024] In accordance with one aspect of the invention, the openings 140 may form a fluid pathway through a heat sink 120 that is substantially perpendicular to a plane in which at least some of the PTC elements 110 are arranged. For example, air may pass through the heating element 100 in a direction approximately perpendicular to the first heat sink 120 a and a plane of PTC elements 110 (e.g., the plane 210 shown in FIG. 2). As a result, the air may flow sequentially past the heat sinks 120 and PTC elements 110 , e.g., first past the first heat sink 120 a , then past a plane in which at least some of the PTC elements 110 are arranged, and then past the second heat sink 120 b . In the embodiment of FIG. 1, the two heat sinks 120 act as both heat conductors and electrodes for the PTC elements 110 , although such dual operation is not necessary. If a single heat sink 120 is used, the PTC elements 110 and heat sink 120 may be arranged in any suitable arrangement relative to air flow through the heating element 100 , e.g., either the first or second heat sinks 120 a or 120 b may be eliminated. When a single heat sink is used, a complete electric circuit may be constructed by connecting an electrode to the PTC elements 110 on the side opposite the single heat sink 120 .
[0025] In another aspect of the invention, PTC elements 110 may be arranged so that a current direction of the PTC elements 110 , or direction that the current would flow when an electric bias is applied, is substantially parallel to a fluid pathway through a heating element 100 , or a portion of the heating element 100 . For example, although the PTC elements 110 may take any suitable shape, size or other feature, in the FIG. 1 embodiment, the PTC elements 110 each have a pair of opposing, broad-surfaces 180 with a relatively large surface area that are configured to transmit current to and from the heat sinks 120 when an electric bias is applied. In this embodiment, current will flow from one heat sink 120 to another through the PTC elements 110 in a direction approximately parallel to an air path through the heating element 100 .
[0026] In another aspect of the invention, the broad surfaces 180 , which may be the surfaces with the largest surface area of the PTC element 110 , may be approximately perpendicular to the fluid pathway. For example, the broad opposing surfaces 180 may be aligned such that at least some of the PTC elements 110 are arranged in one or more planes, such as the plane 210 shown in FIG. 2. In this embodiment, the fluid flow direction through the heating element 100 is approximately perpendicular to the surfaces 180 of the PTC elements 110 . The approximately perpendicular direction of fluid flow through the heating element 100 need not require that all individual flow paths in an overall fluid flow or all molecules in a fluid flow follow a perpendicular path through the heating element, but rather that the overall direction of movement of air is approximately perpendicular to the heating element. For example, water flow in a river is said to generally be in a particular direction, i.e., the overall flow direction of the river, even though particular parts of the river may have currents, eddies and other flows that are not necessarily aligned with the overall flow of the river. A similar situation may exist in the fluid flow through the heating element, and thus fluid flow direction may refer either to particular localized flow or the overall flow of fluid through the element.
[0027] In another aspect of the invention, the PTC elements may be arranged in a radial arrangement in a way similar to spokes in a bicycle wheel. For example, as shown in FIG. 1, the PTC elements 110 may have a radial arrangement such that the PTC elements 110 are arranged within a circle 150 . As seen in FIG. 1, the radial arrangement may include any suitable number of radial spokes, or flanges 160 , and any number of PTC elements in any one of the flanges 160 . A radial arrangement of PTC elements 110 within a circle 150 may provide an even heat distribution in the heating element 100 , e.g., when a standard radial fan is used to move fluid through and/or around the heating element 100 . Of course, the PTC elements 110 may be arranged in any suitable way, such as in a linear array, a concentric circular pattern, and so on.
[0028] In another aspect of the invention, since the heat sinks 120 may be thermally conductive, the PTC elements 110 may be thermally coupled to the heat sinks 120 such that they transfer at least a portion of the heat they generate to at least one heat sink 120 . For example, the PTC elements 110 may transfer at least 50% of the heat they generate to one or more heat sinks 120 . Preferably, the PTC elements 110 transfer at least 70% of the heat they generate to the heat sinks 120 . More preferably, the PTC elements 110 transmit at least 80% of the heat they generate to the heat sinks 120 . Because the heat from the PTC elements 110 may be transferred to the heat sinks 120 by conduction, the contact surface area between the heat sinks 120 and the PTC elements 110 may be relatively large. Although in the FIG. 1 embodiment the contact area between the heat sinks 120 and the PTC elements 110 is flat, the contact area may have any suitable surface features, such as corrugations, grooves, recesses, etc., to enhance thermal and/or electrical contact between the heat sinks 120 and the PTC elements 110 .
[0029] In another aspect of the invention and as discussed above, the heat sinks 120 may act as electrodes for the PTC elements 110 . When used as electrodes, the heat sinks 120 may stabilize current spikes and thus protect the PTC elements 110 . Therefore, the heat sinks 120 may be in electrical contact with the PTC elements 110 and may include an electrically conductive material such as a metal. The heat sinks 120 may also include a thermally and electrically conductive material such as copper, stainless steel, or steel. In this embodiment, the heat sinks 120 are formed from a plate or sheet of metal, such as aluminum, and the openings are stamped, machined or otherwise produced in the sheet. However, aspects of the invention are not limited to heat sinks 120 that are formed as flat plates, but instead may have any suitable arrangement, whether for functioning as an electrode or a heat transfer mechanism. For example, the heat sinks 120 may have fins, corrugations, or other features to enhance heat transfer. In addition, the heat sinks 120 need not be made from a single material or as a single piece. Instead, the heat sinks 120 may be made in multiple parts and/or from two or more different materials. Furthermore, the heat sink materials may include insulators, conductors and/or semiconductors in any suitable arrangement. If desired, a conductive grease can also be used between the PTC elements 110 and the heat sinks 120 to improve the electrical and/or thermal contact between these elements. With the heating element 100 configured in this way, one of the heat sinks 120 can be positively electrically charged and the second can be electrically neutral as shown in FIG. 2.
[0030] The openings 140 in the heat sinks 120 may be sized and configured to provide both a large surface area for effective heat convection and heat and/or electrical conduction as well as large vents to promote relatively unhindered air flow through the heating element 100 . As known by those of skill in the art, the configuration of openings 140 can be designed and configured for the specific fan blade size, volume of unheated fluid moving through the heating element 100 , and amount of expansion of the fluid due to heating occurring within the heating element 100 .
[0031] Although not necessary, the openings 140 in the heat sinks 120 may be aligned to create a substantially straight fluid pathway through the heating element 100 and thus reduce resistance to fluid flow. The fluid pathway created by the openings 140 may be substantially parallel to the current direction through the PTC elements 110 when an electric bias is applied and/or substantially perpendicular to the opposing broad sides of the PTC elements 110 .
[0032] In one aspect of the invention, the heat sinks 120 may substantially shield the PTC elements 110 from the fluid pathway. For example, as shown in FIG. 1, if the PTC elements 110 are aligned under solid portions of the heat sinks 120 , the heat sinks 120 may substantially shield the PTC elements 110 from direct fluid flow and furthermore may provide a larger conductive and convective heat transfer surface for the fluid and PTC elements 110 . In one embodiment, the heat sinks 120 substantially shield the PTC elements 110 from the fluid pathway such that the fluid pathway may be adjacent to less than 50% of the PTC elements' 110 surface area. In other words, the fluid pathway does not contact the majority of the PTC elements' 110 surface area. The fluid pathway may preferably be adjacent to less than 30% of the PTC elements' 110 surface area. More preferably, the fluid pathway may be adjacent to less than 20% of the PTC elements' 110 surface area. However, it should be understood that the PTC elements 110 may be partially or wholly exposed to fluid flow by the openings 140 in the heat sinks 120 , and the PTC elements 110 may include openings through which fluid flows as well.
[0033] As shown in FIGS. 1 and 2, the heating element 100 may include fasteners 130 , such as rivets, bolts, screws, etc., which hold the PTC elements 110 firmly between the heat sinks 120 . If one heat sink is used, fasteners 130 may be employed to hold the PTC elements 110 to the heat sink 120 . Additionally, if the heat sinks 120 are used as electrodes, the fasteners 130 may be electrically non-conductive, e.g., at least partially composed of plastics, ceramics, and non-conductive metals. Using non-conductive materials for the fasteners 130 may prevent the heating unit 100 from electrically short circuiting when an electric bias is applied. However, other means, such as interposing an insulating material between the fasteners 130 and the heat sinks 120 , are available to prevent short circuiting as known by those of skill in the art. Of course, the heating element 100 may be held together by other means, such as one or more clamps, adhesives, etc. or a combination of fasteners, clamps, adhesives, etc.
[0034] The fasteners 130 may be sized and configured to generate pressure between the PTC elements 110 and the heat sinks 120 , thereby creating sufficient contact between the heat sinks 120 and the PTC elements 110 . Sufficient pressure between the PTC elements 110 and heat sinks 120 may help secure the PTC elements 110 in place and/or may improve the electrical and/or thermal contact between the heat sinks 120 and the PTC elements 110 , thereby potentially making the heating element 100 more efficient. The fasteners 130 may be placed around or through the PTC elements 110 such that they generate pressure directly on the PTC elements 110 .
[0035] Several aspects of the present invention have been described. However, many modifications to the described embodiment can be made within the scope of the present invention. For example, the PTC elements 110 may have a rectangular, sheet-like shape, as shown in FIG. 1. However, as known to those of skill in the art, any suitable shape may be used. As also shown in FIG. 1, multiple PCT elements 110 can be placed on a single radial flange, e.g., 110 a and 110 b on 160 d . Although the PTC element arrangement in FIG. 1 has sixteen PTC elements 110 arranged with two PTC elements 110 per radial flange 160 , many alternative radial PTC element arrangements are possible as shown in FIGS. 3 through 6. More or fewer than two PTC elements 110 can be placed per flange 160 , and the number of flanges 160 can likewise vary. Because each PTC element 110 may have a power limit, positioning multiple PTC elements 110 on a single radial flange 160 may allow the heating element 100 to produce more heat per flange without damaging the PTC elements 110 . Additionally, the number, sizes, and shapes of PTC elements 110 included in each flange 160 do not have to be uniform between radial flanges 160 , as shown in FIGS. 5 and 6. Thus, the arrangement of PTC elements 110 can be sized and configured to provide the desired power output while maintaining a desired heat distribution within the heating element 100 . That is, the heater 100 may be configured to have an uneven internal heat distribution, although in many cases an even internal heat distribution may be desirable.
[0036] In another embodiment of the present invention, the PTC elements 110 can be placed in a grid-like pattern. As shown in FIGS. 7 - 9 , the perimeter of this grid-like pattern can be square, rectangular, or any other shape with any number and shape of PTC elements 110 aligned in the grid. Again, the PTC element grid can be sized and configured to optimize the heating element 100 for its desired use.
[0037] Many other PTC element configurations are possible. Two alternative configurations are shown in FIGS. 10 and 11. Notably, for all of the PTC element configurations of FIGS. 3 through 11, the PTC elements 110 are arranged such that the broad opposing surfaces 180 of the PTC elements are aligned in one or more planes. As noted above, to increase the conductive surface area with the heat sinks 120 , the broad opposing surfaces 180 also may be the sides with the largest surface area.
[0038] Although in FIG. 1 the openings 140 in the heat sinks 120 have an arcuate shape, the openings 140 can have any suitable configuration, size and/or shape. Specifically, the openings 140 can be rectangular slots that are radially oriented, rectangular slots that are arranged like chords, triangular holes, circular holes, or any other configuration of shapes and sizes. The shape of the heat sink 120 and placement of the solid portions and openings 140 of the heat sink can be altered to accommodate different PTC element configurations. For example, the heat sinks 120 can be configured such that their solid portions substantially shield the PTC elements 110 from direct airflow regardless of the PTC element configuration chosen.
[0039] Although the fasteners 130 are located at the ends of the radial flanges 160 in FIG. 1, the fasteners 130 may be placed in many different locations in the heating element 100 . For example, the fasteners 130 alternatively or additionally can be placed along the sides of the radial flanges 160 or between the radial flanges 160 . The fasteners 130 may also be configured to hold a clamping mechanism or brace instead of contacting the heat sinks 120 directly. If it includes an electrically insulating material, a clamping mechanism or brace could additionally be used to prevent short circuiting when the heat sinks 120 are used as electrodes.
[0040] The fasteners 130 may be any of various types as well. Rivets are depicted in FIG. 1, but as known to those of skill in the art, many types of fasteners such as screws, bolts, press fit fittings, and clamps can also be used. Additionally, welds, epoxy, or other adhesives can be used to fasten the heat sinks 120 together and hold the PTC elements 110 firmly in place with sufficient electrical and thermal contact between the heat sinks 120 and the PTC elements 110 . If an adhesive such as epoxy is used, fasteners 130 may be unnecessary.
[0041] As shown in FIG. 12, a heating element 100 can be used in a portable heater 440 which is sized and configured to allow a single human to carry it without mechanical assistance. In a portable air heater 440 , at least one heating element 100 may be placed in front of air movement means such as a fan 400 inside a housing 410 . The fan 400 may direct air substantially perpendicular to the heating element 100 as shown by the arrows 420 . As the air passes by and/or through the heating element 100 , at least a portion of it is heated by the heat sinks 120 and/or the PTC elements 110 . At least part of the heated air is then vented out of the housing 410 as shown by the arrows 430 .
[0042] Although aspects of the present invention have been fully described by way of example, modifications to the designs can be made within the scope of the invention as known to those of skill in the art. Therefore, the examples used herein should not be construed as limiting, but merely intended to completely describe an illustrative embodiment of the invention.
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At least one aspect of the present invention relates to a system for heating a gas using positive temperature coefficient (PTC) elements. More particularly, aspects of the present invention are directed towards PTC element configurations and orientations. In one aspect of the present invention, PTC elements are interposed between heat sinks such that they transmit current from one heat sink to another. The PTC elements may be arranged in a radial configuration, which may have more than one PTC element per radial flange. The heat sinks may have grilles which allow air to flow perpendicular to the heat sinks and between the PTC elements.
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FIELD OF THE INVENTION
[0001] The field of the invention comprises phase change memory cells, a process for their manufacture, and products made by such process.
BACKGROUND OF THE INVENTION
[0002] There are two major categories of computer memory: non-volatile memory and volatile memory. Non-volatile memory does not require constant input of energy in order to retain information whereas volatile memory does. In non-volatile memory devices, the memory state can be retained for days to decades without power consumption. Examples of non-volatile memory devices comprise Read Only Memory (ROM), Flash Electrical Erasable Read Only Memory, Ferroelectric Random Access Memory (FRAM), Magnetic Random Access Memory (MRAM), and Phase Change Memory.
[0003] Examples of volatile memory devices comprise Dynamic Random Access Memory (DRAM) and Static Random Access Memory (SRAM); where DRAM requires the memory element to be constantly refreshed while SRAM requires a constant supply of energy to maintain the state of the memory element.
[0004] Phase change materials (PCM) are poised to play a fundamental role in new solid state phase change memory and storage devices. In order to comply with the requirements imposed by the scaling road map, it is expected that the memory cells will be of the confined type, where the PCM is deposited via chemical vapor deposition (CVD) or atomic layer deposition (ALD) processes into a predefined cavity.
[0005] Phase change memory involves manipulating specific materials (PCM's) into different phases to store information. Each phase exhibits different electrical properties which enables the PCM to store information. The amorphous and crystalline phases are typically two phases used for bit storage (1's and 0's) since they have detectable differences in electrical resistance. Specifically, the amorphous phase has a higher resistance than the crystalline phase.
[0006] Chalcogens comprise non-metallic Group VIA elements (Periodic Table Group VIA [IUPAC Form]) commonly used to form phase change materials, i.e., compounds or alloys (also referred to herein as “a combination or combinations”) with another element, and sometimes referred to as “chalcogenide” PCM's. Selenium (Se) and tellurium (Te) are the two most common chalcogens used to produce these compounds or alloys (“combinations”).
[0007] Exposing the PCM to laser or electrical pulses of different intensity and duration repeatedly switches the PCM between crystalline and amorphous phases. A short intense pulse melts the material, which is subsequently quenched into the amorphous phase; a less intense pulse heats the material above the crystallization temperature and reverses the process.
[0008] An important step to obtain optimal performance of PCM cells is to densify the PCM after deposition via a rapid thermal annealing or laser annealing process. The latter steps may have unintended consequences due to action of capillary forces at the PCM/spacer interface of the cell during the densification process. This could produce a detachment of the PCM at the bottom contact of the PCM cell.
RELATED ART
[0009] The following patents and published applications provide examples of the state of the art of PCM memory cells:
Breitwisch, et al., United States Patent Application Publication 2010/0078621; Horii, et al., United States Patent Application Publication 2010/0081263, and U.S. Pat. No. 7,767,491; Kang, United States Patent Application Publication 2009/0206317; Chen, United States Patent Application Publication 2009/0189140; An et al., U.S. Pat. No. 7,777,212; Chae, et al., U.S. Pat. No. 7,772,101; Shin, et al. U.S. Pat. No. 7,777,214.
SUMMARY OF THE INVENTION
[0017] The present invention comprises structures, articles of manufacture, processes and products produced by the processes that address the foregoing needs, and provides substantially optimal performance PCM cells.
[0018] We form a PCM cell by depositing a PCM in a via opening in a dielectric layer lined with spacer material to form a PCM/spacer interface that extends into the dielectric layer for a distance and terminates at an electrode contact. We then remove part of the dielectric layer at the opening to leave a small part of the PCM to extend out of the opening and form a cusp, and then place a low density capping film on the dielectric layer to envelop the cusp. We densify the PCM after deposition via a rapid thermal annealing or processing (RTP) to substantially prevent a diffusion process from taking place in the selecting devices. The thermal processing also densifies the low density capping film causing it to compress the PCM in the via against the electrode contact. This densification substantially avoids or minimizes detachment of the PCM at the electrode contact of the PCM cell.
[0019] The low density capping film could be for example Si-Nitride, Al-Nitride, Boron Nitride all deposited at low temperature in the range of about 150 to about 300 Degree C.
[0020] Rapid thermal annealing or processing (RTP) refers to a semiconductor manufacturing process which heats silicon wafers to high temperatures (up to about 1,200° C. or greater) on a timescale of several seconds or even millisecond range. During cooling, however, wafer temperatures must be brought down slowly so they do not break due to thermal shock. Such rapid heating rates are often attained by high intensity lamps or lasers. The latter are more appropriate for ultra-fast heating. These processes are used for a wide variety of applications in semiconductor manufacturing including dopant activation, thermal oxidation, metal reflow and chemical vapor deposition.
[0021] Stated otherwise, RTP comprises (a) a pre-anneal step which includes heating to a temperature and for a period sufficient to preheat the wafer so as to reduce thermal shock due to a main annealing step, (b) the main annealing step being at a temperature and for a period sufficient to provide the densification of the PCM and the capping film, and (c) a post-anneal step carried out at a temperature and for a period sufficient to relieve stresses which may result from the main-annealing step.
[0022] In one embodiment RTP comprises, in succession, exposure of the device in a pre-anneal step at temperatures ranging from about 400.degrees to about 500.degrees C. for a period of from about 20 to about 40 seconds, the main annealing step at a peak temperature within a range of from about 650.degrees to about 850.degree C. for a period of from about 5 to about 2000 milliseconds, and the post-anneal step at temperatures ranging from about 400.degrees to about 500.degrees C. for a period of from about 25 to about 35 seconds, followed by cool down at a rate of from about 5 degrees to about 10 degrees C. per second, in either a nitrogen, oxygen, Ar, or He atmosphere
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying drawings are not necessarily drawn to scale but nonetheless set out the invention, and are included to illustrate various embodiments of the invention, and together with this specification also serve to explain the principles of the invention. These drawings comprise various Figures that ilustrate a compressive strucutre for enhancing contacts in phase change material memory cells.
[0024] FIGS. 1 to 4 comprise side elevations in cross-section illustrating PCM devices in various stages of manufacture according to the invention and inherently show steps in a process for manufacturing these PCM devices.
[0025] FIG. 5 comprises a side elevation in cross-section illustrating the additional steps used to convert these PCM devices into PCM cells.
DETAILED DESCRIPTION OF THE INVENTION
[0026] To achieve the foregoing and other advantages, and in accordance with the purpose of this invention as embodied and broadly described herein, the following detailed description comprises disclosed examples of the invention that can be embodied in various forms.
[0027] The specific processes, compounds, compositions, and structural details set out herein not only comprise a basis for the claims and a basis for teaching one skilled in the art to employ the present invention in any novel and useful way, but also provide a description of how to make and use this invention. Not only do the written description, claims, abstract of the disclosure, and the drawings that follow set forth various features, objectives, and advantages of the invention and how they may be realized and obtained, but these features, objectives, and advantages will also become apparent by practicing the invention.
[0028] We obtain optimal performance of PCM by densification of the PCM after deposition via a rapid thermal annealing or laser annealing process where the PCM is positioned in a via formed in a dielectric material lined with a spacer material. The latter steps may have unintended consequences due to action of capillary forces at the PCM/spacer interface during the densification process, which could produce a detachment of the PCM at the bottom contact in the via which comprises an electrode.
[0029] In order to preserve a robust and reliable bottom electrical contact during the densification process, i.e., enhancing this electrical contact, a low density layer or capping film is coated on a cusp we form in the profile of the exposed PCM following a chemical mechanical polishing step, and capping the exposed PCM. During densification, the capping film also becomes densified and will exert a compressive force on the PCM in a direction toward the bottom contact or electrode which substantially eliminates or minimizes detachment of the PCM at the bottom contact Referring to FIG. 1 , the structure 10 comprises a dielectric layer 14 having a tubular via opening 12 with a spacer layer 18 contiguous with, and substantially extending around the circumference of the outside wall of via 12 . In one embodiment, dielectric 14 comprises silicon oxide, silicon nitride, silicon oxy-nitride, aluminum oxide and/or titanium oxide. Spacer layer 18 may comprise one of SIC, SiN, SiCOH, TiO 2 and Ta 2 O s . or combinations thereof. The spacer layer 18 is introduced to improve the wetting of the phase change material (PCM) to be deposited, and to control the heat transfer during setting, and it is selected to fit the desired properties of the particular PCM/spacer interface.
[0030] After forming spacer 18 we introduce PCM 16 into via 12 by either a chemical vapor deposition process (CVD) or atomic layer deposition process (ALD) known in the art and chemical deposition. This is followed by Chemical Mechanical Polishing (CMP). which has the role of removing the surface part of the spacer and planarizing the surface of the spacer.
[0031] The phase change material 16 comprises a material having two stable states. For example, the phase change material may comprise chalcogenide elements such as tellurium (Te) and/or selenium (Se). In addition, the phase change material may further comprise compounds or alloys (“combinations”) of germanium (Ge), antimony (Sb), bismuth (Bi), palladium (Pd), tin (Sn), silver (Ag), arsenic (As), sulfur (S), silicon (Si), phosphorus (P), oxygen (O) and/or nitrogen (N). For example, the phase change material may comprise Ge—Sb—Te; As—Sb—Te; As—Ge—Sb—Te; Sn—Sb—Te; Ag—In—Sb—Te; In—Sb—Te; a compound layer of a Group VA element (IUPAC Form), antimony (Sb) and tellurium (Te); a compound layer of a chalcogen, antimony (Sb) and tellurium (Te); a compound layer of a Group VA element (IUPAC Form), antimony (Sb) and selenium (Se); and/or a compound layer of a chalcogen (with the exception of selenium (Se)), antimony (Sb) and selenium (Se).
[0032] In one embodiment, “chalcogenide” PCM's, comprise for example, Ge 2 Sb 2 Te 5 , SbTe, and In 2 Se 3 . The so-called Ge—Sb—Te (GST) materials, however, are the PCM's of choice for optical memory devices. They are also the leading candidates for a new generation of non-volatile electronic memory.
[0033] Via 12 and spacer 18 extend toward and terminate at electrode 20 which may comprise at least one of titanium (Ti), titanium nitride (TiN), tantalum nitride (TaN), molybdenum nitride (MoN), niobium nitride (NbN), titanium silicon nitride (TiSiN), titanium aluminum nitride (TiAlN), titanium boron nitride (TiBN), zirconium silicon nitride (ZrSiN), tungsten (W), tungsten nitride (WN), graphite, carbon nitride (CN), tungsten silicon nitride (WSiN), tungsten boron nitride (WBN), zirconium aluminum nitride (ZrAlN), molybdenum silicon nitride (MoSiN), molybdenum aluminum nitride (MoAlN), tantalum silicon nitride (TaSiN), tantalum aluminum nitride (TaAlN), titanium oxynitride (TiON), titanium aluminum oxynitride (TiAlON), tungsten oxynitride (WON) and tantalum oxynitride (TaON). Electrode 20 may be formed by a deposition process such as a physical vapor deposition (PVD) method, a CVD method or an ALD method and a patterning process known in the art. We form the electrode 20 prior to forming the via 12 by methods know in the art, such as patterning an electrode layer, depositing the electrode in the resulting patterned area, followed by building the electrode layer to a greater thickness before forming the via 12 .
[0034] FIG. 2 illustrates a process for recessing dielectric 14 after deposition by means of CMP, the latter also removing the spacer 18 at the surface, exposing the silicon oxide. In order to obtain a cusp on the PCM, a timed wet process using HF is utilized. The latter does not attack the PCM but recesses the silicon oxide field, leaving a PCM cusp.
[0035] FIG. 3 illustrates the next step in the process comprising applying a low density film 24 to coat cusp 22 and extend outwardly from cusp 22 to also coat the surface of dielectric 14 . We then obtain optimal performance of the PCM 16 by densification using rapid thermal processing via a capacitor discharge quartz lamp or laser pulse, densifying the film 24 , and the PCM to high density PCM 28 as illustrated in FIGS. 4 and 5 . For this process to be effective, the recess is programmed such that, the volume of the PCM cusp 22 must be smaller than volume of the PCM inside the via. This reduces the volume forces arising from the cusp 22 which may counterbalance the pressure effect of the densification of film 24 , which aims at attaining a density within 5% of their sintered value: Si-Nitride (˜3.3 g/cc), Al-Nitride˜(3.2 g/cc), B Nitride (˜1.9 g/cc).
[0036] Low density film 24 becomes operatively associated with cusp 22 in the coating process so that PCM 16 densification to high density PCM 28 via rapid thermal processing also converts low density film 24 to high density film 26 that in turn exerts compressive forces on PCM 16 in a direction toward electrode 20 as illustrated in FIG. 4 . These compressive forces substantially eliminate or minimize detachment of PCM 16 from electrode 20 during rapid thermal annealing or laser annealing. The low density films, are not restricted to but preferably comprise dielectrics, and are usually formed by physical or chemical deposition usually at low temperatures. The latter prevents surface diffusion and thus condensation of the film.
[0037] In FIG. 5 we illustrate removal of high density film 26 by CMP to expose dielectric 14 and the top part of the PCM material. FIG. 5 also illustrates the application of an electrode 30 operatively associated with high density PCM 28 at the opening of via 12 . The role of this electrode is to prevent inter-diffusion of PCM/TEC (top electrical contact) materials while being electrically conductive. We then construct a top electrical contact (TEC) 32 by means of a Back End Of Line (BOEL) processes well known to those skilled in the art.
[0038] Throughout this specification, and abstract of the disclosure, the inventors have set out equivalents, of various materials as well as combinations of elements, materials, compounds, compositions, conditions, processes, structures and the like, and even though set out individually, also include combinations of these equivalents such as the two component, three component, or four component combinations, or more as well as combinations of such equivalent elements, materials, compositions conditions, processes, structures and the like in any ratios or in any manner.
[0039] Additionally, the various numerical ranges describing the invention as set forth throughout the specification also includes any combination of the lower ends of the ranges with the higher ends of the ranges, and any single numerical value, or any single numerical value that will reduce the scope of the lower limits of the range or the scope of the higher limits of the range, and also includes ranges falling within any of these ranges.
[0040] The terms “about,” “substantial,” or “substantially” as applied to any claim or any parameters herein, such as a numerical value, including values used to describe numerical ranges, means slight variations in the parameter. In another embodiment, the terms “about,” “substantial,” or “substantially,” when employed to define numerical parameter include, e.g., a variation up to five per-cent, ten per-cent, or 15 per-cent, or somewhat higher.
[0041] All scientific journal articles and other articles, including internet sites, as well as issued and pending patents that this written description or applicants' Invention Disclosure Statements mention, including the references cited in such scientific journal articles and other articles, including internet sites, and such patents, are incorporated herein by reference in their entirety and for the purpose cited in this written description and for all other disclosures contained in such scientific journal articles and other articles, including internet sites as well as patents and the references cited therein, as all or any one may bear on or apply in whole or in part, not only to the foregoing written description, but also the following claims, and abstract of the disclosure.
[0042] Although the inventors have described their invention by reference to some embodiments, other embodiments defined by the doctrine of equivalents are intended to be included as falling within the broad scope and spirit of the foregoing written description, and the following claims, and abstract of the disclosure.
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A process for manufacturing a PCM device comprises forming a dielectric, producing a via in the dielectric starting at an area on the surface of the dielectric by forming a via opening in the area and extending the opening into the dielectric toward and then terminating at an electrode comprising a first electrode in the dielectric. We form a spacer layer contiguous with the side walls of the via and fill the via with a PCM. We then remove the surface of the dielectric to leave a PCM cusp at the opening of the via, cap the PCM cusp with a low density capping film; densify the PCM and capping film to obtain a high density capping film that exerts compressive pressure on the high density PCM in a direction toward the first electrode to enhance electrical contact between the PCM and the first electrode.
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RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Application No. 61/745,248, filed Dec. 21, 2012, which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The invention relates to catheters having expandable members, e.g., balloons, for delivering energy to tissues, i.e., to treat the tissues. The invention also describes methods for monitoring and controlling an amount of energy delivered to the tissue.
BACKGROUND
[0003] Physicians use catheters to gain access to and repair interior tissues of the body, particularly within the lumens of the body such as blood vessels. For example, balloon angioplasty and other catheters often are used to open arteries that have been narrowed due to atherosclerotic disease. Catheters can also be used to deliver devices, e.g., stents or valves to the vasculature. Another common catheter use is to deliver therapy to a tissue, such as a drug, heat, or other forms of energy.
[0004] The process of heating a tissue to treat a disorder is generally known as “ablation,” even when the tissue is not removed. When ablation techniques were first pioneered, they were truly ablative, in that layers of tissue were burned away with high temperature tools. It has since been discovered that many disorders can be treated by merely heating, but not necessarily removing the tissue, because the heating causes changes to the tissue, e.g., scarring, or destroys/diminishes vasculature or nerves underlying the tissue. For example, endometrial ablation is commonly used to control uterine bleeding. Endometrial ablation involves heating the tissue of the uterine lining to cause the tissue to scar and to dilate the underlying vasculature.
[0005] A newer ablation procedure, known as renal denervation (RDN), uses ablative techniques to damage nerves in the walls of the renal arteries. Damage to the nerves in this area affects sympathetic drive, a part of the autonomic nervous system that controls certain body functions when the body is exposed to stress. In particular, destruction of the nerves adjacent to the renal artery results in lower blood pressure, partially because the mechanism by which blood pressure is elevated due to stress is muted. Where approved, the procedure can be used to treat patients that do not respond sufficiently to hypertension medication. Early clinical trials have shown that patients undergoing this procedure commonly experience a sustained decrease in systolic blood pressure of 25-32 mmHg, and a sustained decrease in diastolic pressure of 12-18 mmHg. See “Symplicity™ RDN System Clinical Trial Data,” at http://www.medtronicrdn.com/intl/healthcare-professionals/symplicity-rdn-system/symplicity-clinical-trial-data/index.htm.
[0006] Accordingly, there is a need for advanced ablation devices for performing procedures such as renal denervation.
SUMMARY
[0007] The invention provides methods and devices for heating an inflation fluid in an ablation balloon catheter in order to improve the accuracy of sensors in the balloon. For example, in order to reduce measurement errors, an ablation balloon is filled with an inflation fluid having substantially the same temperature as the target tissue treatment temperature. Because the inflation fluid is heated, the sensors contacting the tissue experience less convective cooling, and the accuracy of tissue temperature measurement is improved. Thus, using the methods and devices of the invention, a surgeon can be assured that the treated tissues were not overheated, but were raised to a temperature sufficient to affect the desired outcome. The treatment methods of the invention are broadly applicable to any ablative procedure, i.e., wherein energy (e.g., heat) is provided to a tissue to affect a therapeutic change.
[0008] Additionally, as described in detail below, the invention includes an expandable balloon having a first temperature sensor integrated into a balloon wall and a second temperature sensor at the distal end of the catheter, typically located away from the balloon wall. The two temperature sensors allow independent measurements of the temperature of the tissue being treated and the temperature of a heated fluid, respectively. The disclosed design increases the accuracy of the tissue temperature measurement made by the first temperature sensor, and results in better outcomes for ablative procedures. In some embodiments, the catheter additionally includes a heating element configured to heat the fluid within the balloon.
[0009] Using the disclosed ablation balloon and methods for applying energy to a subject, it will be safer to ablate tissues, and it will be easier to verify that the tissues have been properly heated to achieve the desired results.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a generalized depiction of a balloon catheter;
[0011] FIG. 2A shows delivery of a balloon catheter of the invention to a tissue in need of treatment;
[0012] FIG. 2B shows the balloon of FIG. 2A being inflated;
[0013] FIG. 2C shows the tissue being treated by increasing the temperature with RF energy;
[0014] FIG. 3 shows an embodiment of an ablation balloon for controlled delivery of energy to a tissue;
[0015] FIG. 4 shows an embodiment of an ablation balloon for controlled delivery of energy to a tissue;
[0016] FIG. 5 shows a flowchart describing an embodiment of a method for controlling delivery of energy to a tissue.
DETAILED DESCRIPTION
[0017] The invention provides improved balloon catheters and methods of using the catheters, as well as other expandable devices, to deliver energy to tissues in need of treatment. In particular, the catheters of the invention allow active monitoring of tissue temperatures to reduce the rate of errors in delivering ablative treatment. Because the catheters of the invention use heated fluids in the balloon, there is less error in the temperature measurements due to convective heat loss. While the description focuses primarily on renal artery ablation for renal denervation (RDN) the devices and methods are broadly applicable to other ablative procedures, such as endometrial ablation or resculpting of atherosclerotic vessels, among others.
[0018] Ablation procedures typically involve contacting a tissue with a hot tool, such as a catheter, or fluid. The heating process often kills the outermost layer of cells contacting the object, and may damage or modify layers of cells below the outermost layer. Some ablation procedures use directed energy to heat and modify the outermost layer of cells, or a nearby layer of cells (treatment depth). In some embodiments, lasers, microwaves, or radiofrequency (RF) waves are directed at the tissue, causing the tissue to heat to treatment temperatures. Typically, the energy is absorbed directly, thus causing the tissue to heat. In some embodiments, a secondary structure, e.g., an antenna, receives the directed energy and heats the tissues. During a procedure the temperature of the tissue is typically elevated to 50° C. or greater, e.g., 55° C. or greater, e.g., 60° C. or greater, e.g., 65° C. or greater, e.g., 70° C. or greater. In some embodiments the tissue is heated to about 65° C., e.g., 68° C.
[0019] In order to minimize risks when performing ablative procedures such as renal denervation (RDN), it is important to monitor and control the temperature of the device and the surrounding tissues. For example, during RDN, the renal artery could be weakened, increasing the chance of embolism, or the renal artery could be perforated or severed. To avoid such damage, prior art devices rely on gated energy delivery to control the temperature of the tissue. That is, RDN devices are programmed to provide predetermined dosing times and wattage based upon accumulated experience and animal/cadaver studies. For example, 4 Watts of radiofrequency energy delivered for 2 seconds has been found to increase the temperature of a cadaver aorta to 65° C. with a particular balloon ablation device. See U.S. Patent Publication No. 2012/0158101 incorporated by reference herein in its entirety. Operation within the suggested range is assumed to provide safe and effective treatment. Nonetheless, without active temperature monitoring, it is impossible to know if the renal artery tissue is overheating. It is also difficult to assure that the target tissue was, in fact, raised to a temperature suitable to denerve the tissue. Using prior art methods, it is impossible to determine if the tissue has been adequately denerved without prolonged blood pressure monitoring after the procedure.
[0020] In order to address these concerns, the invention places an expandable member (e.g., a balloon) having a temperature sensor in proximity to the tissues (e.g., blood vessels), and expands the expandable member to cause the expandable member to contact the tissue and deliver therapy. For example, a heated fluid, having a temperature similar to a target therapy temperature, can be provided to the expandable member to increase the accuracy of tissue temperature measurements. During the ablative procedure, i.e., while energy is applied to the tissue via the expandable member, the tissue temperature is measured with a sensor in the presence of the heated fluid. Based upon the temperature assessments, the treatment is continued until the tissue has reached a target therapeutic temperature. Because the temperature measurement is more accurate than current methods, it is less likely that the tissue will be overheated, and it is more likely that the tissue will reach the target temperature during the procedure.
[0021] FIG. 1 shows an embodiment of a balloon ablation catheter system 10 for treating tissues with heat. The catheter system 10 includes a balloon catheter 12 having a catheter body 14 with a proximal end 16 and a distal end 18 . Catheter body 14 is flexible and defines a catheter axis 15 , and may include one or more lumens, such as a guide wire lumen and an inflation lumen. Additional lumens may be provided for other treatments, such as imaging, perfusion, fluid delivery, etc. Catheter 12 includes an inflatable balloon 20 adjacent distal end 18 and a housing 29 adjacent proximal end 16 . When inflated and energized, inflatable balloon 20 provides thermal RF energy to the tissue, causing it to increase in temperature. Housing 29 includes a first connector 26 in communication with the guide wire lumen and a second connector 28 in fluid communication with the inflation lumen (not shown). The inflation lumen extends between balloon 20 and second connector 28 . Both first and second connectors 26 , 28 may optionally comprise standard connectors, such as Luer-Loc™ connectors.
[0022] Housing 29 also accommodates an electrical connector 38 . Connector 38 includes a plurality of electrical connections, each electrically coupled to electrodes 34 via conductors (not shown). Electrodes 34 are energized and controlled by a controller 40 and power source 42 , such as bipolar or monopolar RF energy, microwave energy, ultrasound energy, voltage source, current source, or other suitable energy source. In an embodiment, electrical connector 38 is coupled to an RF generator via a controller 40 , with controller 40 allowing energy to be selectively directed to electrodes 34 . When monopolar RF energy is employed, the patient may be grounded by connecting an external electrode, or an electrode connected to the catheter body 14 , to the patient.
[0023] The controller 40 includes a processor, or is coupled to a processor, to control and/or record treatment. The processor will typically comprise computer hardware and/or software, often including one or more programmable processor units running machine readable program instructions or code for implementing some or all of one or more of the methods described herein. The code will often be embodied in a tangible media such as a memory (optionally a read only memory, a random access memory, a non-volatile memory, or the like) and/or a recording media (such as a floppy disk, a hard drive, a CD, a DVD, a non-volatile solid-state memory card, or the like). The code and/or associated data and signals may also be transmitted to or from the processor via a network connection, and some or all of the code may also be transmitted between components of catheter system 10 and within processor 40 .
[0024] The balloon 20 generally includes a proximal portion coupled to an inflation lumen and a distal portion coupled to a guide wire lumen. (See FIGS. 4 and 5 .) The balloon 20 expands radially when inflated with a fluid or a gas. In an embodiment, the balloon 20 is constructed from a compliant material that can withstand heat and high pressures. The balloon 20 may be constructed from polyethylene, nylon, polyvinylchloride, or polyethylene terephthalate. The balloon 20 typically is on the order of 2-7 French, i.e., approximately 1-3 mm, in diameter, when in an unexpanded state. Once expanded, the expanding disrupting element may be on the order of 3-8 mm depending upon the pressure on the expanding element and the compliance of the material. In some embodiments, the expanding element will be constructed from a high-compliance material that is able to withstand pressures on the order of 6 to 10 atm. Prior to inflation, the balloon 20 is positioned in the distal end 18 of the catheter. The balloon 20 may have helical folds to facilitate conversion between an expanded (inflated) configuration and a low profile configuration, needed for delivery and removal.
[0025] Catheter bodies intended for intravascular introduction will typically have a length in the range from 50 cm to 200 cm and an outer diameter in the range from 1 French to 12 French (0.33 mm: 1 French), usually from 3 French to 9 French. In the case of fistula treatment catheters, the length is typically in the range from 60 cm to 150 cm, the diameter is preferably below 8 French, more preferably below 7 French, and most preferably in the range from 2 French to 7 French.
[0026] Catheter bodies will typically be composed of a biocompatible polymer that is fabricated by conventional extrusion techniques. Suitable polymers include polyvinylchloride, polyurethanes, polyesters, polytetrafluoroethylenes (PTFE), silicone rubbers, natural rubbers, and the like. Optionally, the catheter body may be reinforced with braid, helical wires, coils, axial filaments, or the like, in order to increase rotational strength, column strength, toughness, pushability, and the like. Suitable catheter bodies may be formed by extrusion, with one or more channels being provided when desired. The catheter diameter can be modified by heat expansion and shrinkage using conventional techniques. The resulting catheters will thus be suitable for introduction to the vascular system, often the coronary arteries, by conventional techniques.
[0027] In an embodiment, the balloon 20 is configured with electrodes 34 integrated into the wall of the balloon 20 to deliver RF energy to heat tissues. The electrodes 34 may be mounted on an inside surface of balloon 20 , with associated connectors/wires extending proximally from the electrodes. The electrodes 34 may be sandwiched between layers of balloon material. The electrodes 34 may be arranged in any suitable pattern, such as stripes, helixes, saw tooth, rings, or arrays.
[0028] The system may be used for monopolar or bipolar application of energy. For delivery of monopolar energy, a ground electrode is used, either on the catheter shaft, or on the patient's skin, such as a ground electrode pad. For delivery of bipolar energy, adjacent electrodes are axially offset to allow bipolar energy to be directed between adjacent circumferential (axially offset) electrodes. In other embodiments, electrodes may be arranged in bands around the balloon to allow bipolar energy to be directed between adjacent distal and proximal electrodes.
[0029] In another embodiment, the system heats tissues using heated fluids. In this configuration, balloon 20 need not include electrodes 34 . In this embodiment, the balloon is substantially impervious to aqueous solutions, e.g., saline, to prevent the heated fluid from leaving the balloon. In an embodiment, the catheter includes an insulated lumen for delivering heated fluids to the balloon, e.g., heated saline. The fluid may have a temperature of 37° C. or greater, e.g., 40° C. or greater, e.g., 45° C. or greater, e.g., 50° C. or greater, e.g., 55° C. or greater, e.g., 60° C. or greater, e.g., 65° C. or greater, e.g., about 68° C. Systems of the catheter 10 , configured to heat tissues with heated fluids may comprise a heated fluid reservoir and a pump connected to the inflation lumen to deliver the heated fluids (not shown). Other embodiments for heating tissues with heated fluids may comprise a heating element inside of the balloon as an element of the catheter. The balloon may be filled with room or body temperature saline directed to the balloon via an inflation lumen, and then the fluid can be heated with the heating element to provide a heated fluid. In some embodiments, a balloon catheter will also include a temperature sensor located proximate to the center of the balloon to be used to measure the temperature of the heated fluid.
[0030] In an embodiment, the balloon 20 is configured with temperature sensors integrated into the wall of the balloon. The temperature sensors may be mounted on an inside surface of balloon 20 , with associated connectors/wires extending proximally from the temperature sensors. The temperature sensors may be mounted on an inside surface of the balloon 20 . The temperature sensors may be sandwiched between layers of balloon material. The temperature sensors may be arranged in any suitable pattern, such as an array. The temperature sensors may be any temperature sensor that has a sufficiently small profile to be incorporated into the balloon, for example the temperature sensors may be a thermocouple, thermistor, thermal diode, or other suitable device. In some embodiments, the catheter will comprise an additional heating element that is inside the balloon, e.g., in proximity to a distal end of the inflation lumen, thereby allowing the inflation fluid, e.g., a heated inflation fluid, to be monitored.
[0031] A generalized depiction of an ablation process is shown in FIGS. 2A-2C . FIGS. 2A-2C show resculpting of a vessel having a plaque deposit and/or thrombus, however the method is analogous to the method used to denerve the renal artery. As seen in FIG. 2A , accessing a treatment site will typically involve advancing a guide wire 74 within a blood vessel 76 to a targeted tissue, such as atherosclerotic material 78 . Locating the balloon 20 may be facilitated by radiopaque markers or by radiopaque structures on or near the balloon 20 . In some instances a guide wire suitable for use with an RF delivery system will be used, such as Safe-Cross™ RF system guide wire. The guide wire may also have imaging or measurement abilities such as the FLOWIRE® Doppler guide wire (Volcano Corporation, San Diego, Calif.). Typically the guide wire will be positioned under fluoroscopic (or other) imaging.
[0032] Regarding FIG. 2A , catheter 12 is advanced distally over guide wire 74 and positioned adjacent to the tissue to be treated, i.e., atherosclerotic material 78 . As shown in FIG. 2B , the balloon 20 is expanded radially within the lumen of the blood vessel so that electrodes 34 radially engage atherosclerotic material 78 . (In denerving an artery, the balloon is simply expanded to the vessel wall) In some instances, electrodes 34 will engage both atherosclerotic material 78 and healthy tissue 80 .
[0033] Once the balloon 20 has engaged the vessel wall tissues, the electrodes 34 will be energized to treat the tissue. As shown in FIG. 2C , RF energy is directed to adjacent pairs of electrodes, treating both atherosclerotic material 78 and the healthy tissue 80 . Most treatments are in the 1 to 6 Watt range, and are performed for a duration of 0.5 to 6 seconds. The duration and power are controlled using feedback from temperature sensors in the balloon, discussed in detail below. Using temperature sensors assures that the tissues are not overheated, but yet heated enough to affect the desired change in the tissue. In some embodiments, the power and duration may also be gated to assure that not enough energy is delivered to cause severe damage to the surrounding tissues.
[0034] Catheters of the invention are described in greater detail in FIGS. 3 and 4 . FIG. 3 shows an expandable member 310 in proximity to a tissue 380 to be treated. Heating elements 320 and temperature sensors 330 are integrated into expandable member 310 . While the expandable member 310 is depicted as a balloon, alternative embodiments may have expandable members 310 that are not balloons. For example, the expandable member 310 could be constructed from a memory wire, such as nitinol, having suitably placed heating elements 320 and temperature sensors 330 to achieve heating of the tissues while monitoring the temperature of the tissue. As shown in FIG. 3 , the expandable member 310 is delivered along a guide wire 370 and is connected to a lumen 340 that is a source for heated fluid. Once expanded, the inner volume 350 of the expandable member may be filled with a heated fluid, i.e., a fluid having a temperature greater than 60° C. In an alternative embodiment, shown in FIG. 4 , the inner volume 350 is filled with a room temperature or body temperature fluid and then the fluid is heated with heating element 420 . The fluid, i.e., the inflation fluid, is typically a biocompatible aqueous solution, such as saline or Ringer's solution. The fluid may additionally comprise contrast agents to facilitate visualization of the balloon and the status of the balloon, i.e., inflated or not inflated. The inner volume 350 can also be filled with a heated fluid and then further heated with heating element 420 . In some embodiments, the catheter of FIG. 4 may also include an additional temperature sensor in proximity to the guide wire 370 , capable of measuring the temperature of the heated fluid in the inner volume 350 , but away from heating elements 330 .
[0035] Once the expandable member 310 is expanded and filled with a heated fluid, the heating elements 320 will be energized to deliver energy to the tissue 380 . Depending upon the procedure, the energy delivered to the tissue 380 will ablate the tissue 380 or affect a change to tissues/structures nearby the tissue 380 such as a nerve 390 . Thus, in a renal denervation procedure, the nerve 390 will be disabled by the delivered energy. While the energy is delivered via heating elements 320 , the temperature sensors 330 will monitor the temperature of the tissue to assure that the tissue does not exceed a safe temperature. The temperature sensors 330 will also monitor the temperature of the tissue to assure that it reaches the temperature needed for treatment.
[0036] In some embodiments, the optimum temperature to achieve renal denervation is 68° C. In this embodiment, the inner volume 350 is filled with a heated fluid also having a temperature of 68° C. As discussed previously, the heated fluid can be provided externally, e.g., through an insulated lumen, or the fluid can be heated once inside the expanding member, e.g., with heating element 420 . Because the catheters are filled with a heated fluid that matches the desired tissue temperature, the heated solution cannot act as a heat sink against the heating elements 320 , as is the case with current ablation catheters. Thus, the temperature sensors 330 will not sense a temperature that is lower than the actual temperature of the tissue, thereby assuring that the tissue is not overheated and damaged. Additionally, the heated fluid will help to provide even heating to the tissue to assure that the desired tissues do reach the desired temperatures.
[0037] When using an expandable member 310 configured as described above, it will not be necessary to gate the energy delivery during treatment. Rather, it will be a simple matter of comparing the temperature measured with the temperature sensor 330 to a predetermined temperature, e.g., 68° C. This method is shown in greater detail in FIG. 5 . As discussed above with respect to FIG. 2A-C , the method begins with placing the expandable member 310 (e.g., balloon) near the tissue to be treated. The balloon is filled with a heated fluid and therapy is delivered by way of heating elements 320 . Temperature sensors 330 monitor the temperature of the tissue being treated to determine a measured temperature (T m ). T m is then compared to a predetermined temperature for treatment, T c , or critical temperature. If T m is less than T c , the catheter is allowed to continue delivering therapy via the heating elements 320 . However if T m is equal to or greater than T c , the heating elements are turned off, to avoid damaging the tissue. Once the therapy is completed, the heated fluid will be removed, typically by flushing away with a cooler fluid, e.g., room temperature saline. In other embodiments, the heated fluid may be simply evacuated with suction.
[0038] Advanced embodiments of the methods may include algorithms for monitoring or measuring the treatment area temperature. For example, readings from multiple temperature sensors 330 at different points on expandable member 330 may be modeled to develop a heat map of how the tissue is heating. Additionally, if the heating elements are individually addressable, it may be possible to turn some off and leave others on in order to achieve more even heating. Other algorithms may be used to estimate overshoot to determine if and when the heating elements should be turned off prior to T m exceeding T c .
[0039] In some embodiments, a catheter of the invention will additionally include imaging capabilities, such as intravascular ultrasound (IVUS) imaging or optical coherence tomography (OCT). The IVUS imaging assembly may be phased array IVUS imaging assembly, an pull-back type IVUS imaging assembly, or an IVUS imaging assembly that uses photoacoustic materials to produce diagnostic ultrasound and/or receive reflected ultrasound for diagnostics. IVUS imaging assemblies and processing of IVUS data are described for example in Yock, U.S. Pat. Nos. 4,794,931, 5,000,185, and 5,313,949; Sieben et al., U.S. Pat. Nos. 5,243,988, and 5,353,798; Crowley et al., U.S. Pat. No. 4,951,677; Pomeranz, U.S. Pat. No. 5,095,911, Griffith et al., U.S. Pat. No. 4,841,977, Maroney et al., U.S. Pat. No. 5,373,849, Born et al., U.S. Pat. No. 5,176,141, Lancee et al., U.S. Pat. No. 5,240,003, Lancee et al., U.S. Pat. No. 5,375,602, Gardineer et at., U.S. Pat. No. 5,373,845, Seward et al., Mayo Clinic Proceedings 71(7):629-635 (1996), Packer et al., Cardiostim Conference 833 (1994), “Ultrasound Cardioscopy,” Eur. J.C.P.E. 4(2):193 (June 1994), Eberle et al., U.S. Pat. No. 5,453,575, Eberle et al., U.S. Pat. No. 5,368,037, Eberle et at., U.S. Pat. No. 5,183,048, Eberle et al., U.S. Pat. No. 5,167,233, Eberle et at., U.S. Pat. No. 4,917,097, Eberle et at., U.S. Pat. No. 5,135,486, and other references well known in the art relating to intraluminal ultrasound devices and modalities. All of these references are incorporated by reference herein.
[0040] In other embodiments, the imaging may use optical coherence tomography (OCT). OCT is a medical imaging methodology using a miniaturized near infrared light-emitting probe, and is capable of acquiring micrometer-resolution, three-dimensional images from within optical scattering media (e.g., biological tissue). OCT systems and methods are generally described in Castella et al., U.S. Pat. No. 8,108,030, Milner et al., U.S. Patent Application Publication No. 2011/0152771, Condit et al., U.S. Patent Application Publication No. 2010/0220334, Castella et al., U.S. Patent Application Publication No. 2009/0043191, Milner et al., U.S. Patent Application Publication No. 2008/0291463, and Kemp, N., U.S. Patent Application Publication No. 2008/0180683, the content of each of which is incorporated by reference in its entirety.
[0041] Other embodiments of catheters and methods of using them, not disclosed herein, will be evident to those of skill in the art, and are intended to be covered by the claims listed below.
INCORPORATION BY REFERENCE
[0042] References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.
EQUIVALENTS
[0043] Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.
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Catheters having expandable members, e.g., balloons, incorporating heating elements and temperature sensors for controlled delivering of energy to tissues, i.e., to treat diseases, especially hypertension. The invention also describes methods for monitoring and controlling the amount of energy delivered to the tissue.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to loading resources in software applications, and more particularly, to detecting stale cached resources.
[0002] Software applications are often arranged as a suite of separate software components or resources. A main component or runtime environment will import resources from resource containers in order to operate as a complete software application. For example, an application may locate and access runtime functions stored in dynamic link libraries, or classes stored in class libraries. In order to locate such resources, a search path is used to indicate the location(s) of one or more such resource containers. For example, in the Java™ runtime environment a CLASSPATH environment variable can be used to define where classes can be found (Java is a trademark of Sun Microsystems Corp. in the United States, other countries, or both). The CLASSPATH is a list of locations (such as directories in a file system or fully qualified class library locations) and is used at runtime when a new class is loaded. Such search paths are ordered such that the application searches for required resources at a first location, before proceeding to subsequent locations in a sequential manner.
[0003] FIG. 1 is a block diagram of a resource processor 108 for loading resources from one or more resource containers 100 in the prior art. The resource processor 108 can be an application at runtime, or a runtime environment such as a Java virtual machine. The one or more resource containers 100 can be, for example, library files, class files, Java archive (jar) files or directories in a file system. Each of the resource containers 100 has a container identifier 102 such as the container name (e.g. a fully qualified jar file name or a fully qualified directory name). Within a resource container 100 can reside one or more resources 104 . The one or more resources 104 can be, for example, class files or runtime libraries. Each of the resources 104 has an identifier, such as a class file name.
[0004] The resource processor 108 includes a resource loader 110 such as a class loader. The resource loader 110 is able to locate a resource 104 in a resource container 100 and load it into a memory of the computer system for use by the resource processor 108 . The resource processor 108 further comprises a resource cache 112 , which is a reserved section of memory in a computer system for storing one or more resources 116 which have been loaded from resource containers 100 . The resource cache 112 can be a shared memory cache serving multiple resource loaders (not shown) or multiple resource processors (not shown). For example, the resource cache 112 can serve multiple Java class loader instances. The resource cache 112 can therefore exist outside the resource processor 108 , such as on a separate computer system communicatively connected to the resource processor 108 . The resources 116 stored in the resource cache 112 can be stored based on usage criteria, such as most frequently used resources. Each of the resources 116 in the resource cache 112 includes a resource identifier 118 . It will be appreciated that the resources 116 stored in the resource cache 104 substantially reflect the resources 104 stored in resource containers 100 when they are loaded into the resource cache 112 by the resource loader 110 . Thus, the resources 116 stored in the resource cache 112 are copies of the resources 104 stored in resource containers 100 .
[0005] When searching for a particular resource the resource loader 110 uses a resource search path 114 . The resource search path 114 includes an ordered container list 120 which is a list of resource containers. Each entry in the resource search path 114 includes an index 122 (the means by which the ordered container list 120 is ordered) and a container identifier 124 (corresponding to a container identifier 102 of one of the resource containers 100 ).
[0006] At runtime, the resource processor 108 requests that the resource loader 110 loads a particular resource identified by a resource identifier 106 . The resource loader 110 first checks if the required resource is resident in the resource cache 112 . If so, the resource can be quickly loaded from the resource cache 112 . If not, the resource loader 110 locates the resource by searching sequentially through each of the resource containers in the ordered container list 120 of the resource search path 114 . When a resource container is located with the required resource identifier 106 the resource loader 110 loads the required resource and may further add the loaded resource to the resource cache 112 .
BRIEF SUMMARY OF THE INVENTION
[0007] According to a first aspect of the present invention, a method loads a resource in a software application. The software application comprises an ordered search path identifying at least one of a plurality of resource containers. Each of the resource containers having a timestamp and an index in the ordered search path. The method comprises loading a resource from an originating resource container, the originating resource container having an index in the ordered search path, identifying a set of resource containers in the ordered search path, each of the set of resource containers having an index less than or equal to the index of the originating resource container, generating a cached resource as a copy of the loaded resource, the cached resource comprising the index of the originating resource container and a cached resource timestamp, the cached resource timestamp corresponding to a maximum timestamp of the resource containers in the set of resource containers, and marking the cached resource as invalid in response to a determination that a resource container in the set of resource containers has a timestamp later than the cached resource timestamp, and the identified resource container comprises the cached resource.
[0008] According to another aspect of the present invention, an apparatus loads a resource in a software application. The software application comprises an ordered search path identifying at least one of a plurality of resource containers. Each of the resource containers includes a timestamp and an index in the ordered search path. The apparatus comprises a loading module loading a resource from an originating resource container, the originating resource container having an index in the ordered search path, an identification module identifying a set of resource containers in the ordered search path, each of the set of resource containers having an index less than or equal to the index of the originating resource container, a generation module generating a cached resource as a copy of the loaded resource, the cached resource comprising the index of the originating resource container and a cached resource timestamp, the cached resource timestamp corresponding to a maximum timestamp of the resource containers in the set of resource containers, and a marking module marking the cached resource as invalid in response to a determination that a resource container in the set of resource containers has a timestamp later than the cached resource timestamp and the identified resource container comprises the cached resource.
[0009] According to yet another aspect of the present invention, a computer program product loads a resource in a software application. The software application comprises an ordered search path identifying at least one of a plurality of resource containers. Each of the resource containers includes a timestamp and an index in the ordered search path. The computer program product comprises a computer usable medium having computer useable program code embodied therewith. The computer useable program code comprises computer usable program code configured to load a resource from an originating resource container, the originating resource container having an index in the ordered search path, computer usable program code configured to identify a set of resource containers in the ordered search path, each of the set of resource containers having an index less than or equal to the index of the originating resource container, computer usable program code configured to generate a cached resource as a copy of the loaded resource, the cached resource comprising the index of the originating resource container and a cached resource timestamp, the cached resource timestamp corresponding to a maximum timestamp of the resource containers in the set of resource containers, and computer usable program code configured to mark the cached resource as invalid in response to a determination that a resource container in the set of resource containers has a timestamp later than the cached resource timestamp and the identified resource container comprises the cached resource.
[0010] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art or science to which it pertains upon review of the following description in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] FIG. 1 is a block diagram of a resource processor for loading resources from one or more resource containers in the prior art;
[0012] FIG. 2 is a block diagram of a computer system suitable for the operation of embodiments of the present invention;
[0013] FIG. 3 is a block diagram of a resource processor for loading resources from one or more resource containers in accordance with an aspect of the present invention;
[0014] FIG. 4 a is a flowchart for a method of the resource loader of FIG. 3 to load a resource with a required resource identifier in accordance with an aspect of the present invention;
[0015] FIG. 4 b is a flowchart for a method of the resource loader of FIG. 3 to load a resource with a required resource identifier from a resource container in accordance with an aspect of the present invention;
[0016] FIG. 4 c is a flowchart for a method of the stale cache checker of FIG. 3 to determine if a cached resource in the resource cache of FIG. 3 is stale in accordance with an aspect of the present invention;
[0017] FIG. 4 d is a flowchart for a method of the resource loader of FIG. 3 to calculate the maximum timestamp of a cached resource in accordance with an aspect of the present invention;
[0018] FIG. 5 is an illustration of an exemplary time line of changes to Java archive (jar) files and class loading operations in accordance with an aspect of the present invention;
[0019] FIG. 6 a is a block diagram of a Java virtual machine (JVM) for loading classes from one or more Java archive (jar) files in accordance with an aspect of the present invention;
[0020] FIG. 6 b is a block diagram of the Java virtual machine (JVM) of FIG. 6 a with the class “R” loaded and cached in the class cache in accordance with an aspect of the present invention;
[0021] FIG. 6 c is a block diagram of the Java virtual machine (JVM) of FIG. 6 b with a new class “R” added to the “A.jar” Java archive (jar) file in accordance with an aspect of the present invention;
[0022] FIG. 6 d is a block diagram of the Java virtual machine (JVM) of FIG. 6 c with the class “R” loaded and cached in the class cache in accordance with an aspect of the present invention; and
[0023] FIG. 6 e is a block diagram of the Java virtual machine (JVM) of FIG. 6 d with a new class “R” added to the “C.jar” Java archive (jar) file in accordance with an aspect of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] As will be appreciated by one of skill in the art, the present invention may be embodied as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Furthermore, the present invention may take the form of a computer program product on a computer-usable storage medium having computer-usable program code embodied in the medium.
[0025] Any suitable computer readable medium may be utilized. The computer-usable or computer-readable medium may be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a nonexhaustive list) of the computer-usable or computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a transmission media such as those supporting the Internet or an intranet, or a magnetic storage device. Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory. In the context of this document, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
[0026] Computer program code for carrying out operations of the present invention may be written in an object oriented programming language such as Java7, Smalltalk or C++. However, the computer program code for carrying out operations of the present invention may also be written in conventional procedural programming languages, such as the “C” programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
[0027] The present invention is described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
[0028] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.
[0029] The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
[0030] FIG. 2 is a block diagram of a computer system suitable for the operation of embodiments of the present invention. A central processor unit (CPU) 202 is communicatively connected to a storage 204 and an input/output (I/O) interface 206 via a data bus 208 . The storage 204 can be any read/write storage device such as a random access memory (RAM) or a non-volatile storage device. An example of a non-volatile storage device includes a disk or tape storage device. The I/O interface 206 is an interface to devices for the input or output of data, or for both input and output of data. Examples of I/O devices connectable to I/O interface 206 include a keyboard, a mouse, a display (such as a monitor) and a network connection.
[0031] FIG. 3 is a block diagram of a resource processor 308 for loading resources from one or more resource containers 300 in accordance with an aspect of the present invention. Many of the elements of FIG. 3 are identical to those described above with respect to FIG. 1 and these will not be repeated here. Each of the resource containers 300 of FIG. 3 further include a timestamp 303 which reflects the creation time of a resource container or the time of the most recent modification to the resource container. For example, the timestamp 303 can be a date and time attribute of a jar file. Alternatively, the timestamp 303 could be stored in an ordered container list 320 , which is described in detail below. Furthermore, the resources 316 stored in the resource cache 312 include, in addition to the resource identifier 318 , a container path index 326 and a maximum timestamp 328 . The container path index 326 is an index of a resource container in the ordered container list 320 which contains the resource. The maximum timestamp 328 is the latest (highest) timestamp of all of the resource containers in the ordered container list 320 up to and including the resource container with the container path index 326 . A method for calculating the maximum timestamp 328 is considered in detail below with respect to FIG. 4 d . Additionally, the resource loader 310 includes a stale cache checker 311 which determines whether resource in the resource cache 312 is stale. A resource in the resource cache 312 is stale if a newer version of the resource would be loaded from one of the resource containers 300 in an equivalent system without a resource cache 312 . A method of the stale cache checker 311 for determining if a resource is stale is considered in detail below with respect to FIG. 4 c.
[0032] FIG. 4 a is a flowchart for a method of the resource loader 308 of FIG. 3 to load a resource with a required resource identifier in accordance with an aspect of the present invention. At step 402 the resource loader 310 determines if a resource with the required resource identifier is stored in the resource cache 312 . If the resource is not stored in the resource cache 312 the method proceeds to step 406 where the method loads a resource with the required resource identifier from the resource containers 300 using the resource search path 314 using the method of FIG. 4 b considered in detail below. If, at step 402 , a resource with the required resource identifier is stored in the resource cache 312 the method proceeds to step 404 . At step 404 the stale cache checker 311 determines if the resource with the required resource identifier in the resource cache 312 is stale. This is achieved using the method of FIG. 4 c considered in detail below. If step 404 determines that the resource is stale the method proceeds to step 406 . Alternatively, if the resource is not stale the method proceeds to step 408 where the resource loader 310 loads the resource with the required identifier directly from the resource cache 312 .
[0033] FIG. 4 b is a flowchart for a method of the resource loader 310 of FIG. 3 to load a resource with a required resource identifier from a resource container in accordance with an aspect of the present invention. At step 420 a loop is initiated through all of the resource containers in the ordered container list 320 . The loop of step 420 is sequential starting at a first entry in the ordered container list 320 (for example, starting at a lowest index 322 ). At step 422 , for a current resource container in the ordered container list 320 , the method determines if the current resource container contains a resource with the required resource identifier. If the current resource container does not contain a resource with the required resource identifier the method proceeds to step 428 where the method loops back to step 420 until the end of the ordered container list 320 is reached. Alternatively, if step 422 determines that the current resource container does contain a resource with the required resource identifier, the method proceeds to step 424 where the resource loader loads the resource with the required resource identifier from the current resource container. Subsequently, at step 426 , the resource loader creates a cached copy of the loaded resource. In an alternative embodiment the creation of the cached copy of the resource at step 426 can be dependent upon criteria such as the frequency of use of the resource. If, after looping through all resource containers in the ordered container list 320 a resource with the required resource identifier is not located, the method notes this as step 430 .
[0034] FIG. 4 c is a flowchart for a method of the stale cache checker 311 of FIG. 3 to determine if a cached resource in the resource cache 312 of FIG. 3 is stale in accordance with an aspect of the present invention. At step 440 a loop is initiated through all of the resource containers in the ordered container list 320 . The loop of step 440 is sequential starting at a first entry in the ordered container list 320 (for example, starting at a lowest index 322 ). At step 442 , for a current resource container in the ordered container list 320 , the method determines if a timestamp 303 of the current resource container is greater than the maximum timestamp 328 of the cached resource. If the timestamp 303 of the current resource container is not greater than the maximum timestamp 328 of the cached resource the method proceeds to step 448 . Alternatively, If the timestamp 303 of the current resource container is greater than the maximum timestamp 328 of the cached resource the method proceeds to step 444 . At step 444 the method determines if the current resource container contains a resource with the resource identifier 318 of the cached resource. If the current resource container contains a resource with the resource identifier 318 of the cached resource the method proceeds to step 446 , otherwise the method proceeds to step 448 . At step 446 the method determines that the cached resource is stale and the method terminates. At step 448 the method determines if the index of the current resource container in the ordered container list 320 is the same as the container path index 326 of the cached resource. If the index of the current resource container in the ordered container list 320 is not the same as the container path index 326 of the cached resource, the method loops back to step 440 for a next resource container in the ordered container list 320 . Otherwise the method proceeds to step 450 where the method determines that cached resource is not stale and the method terminates. In this way the method of FIG. 4 c is able to determine if a cached resource is stale by verifying that no resource container in the ordered container list 320 up to and including the resource container having the container path index 326 has a timestamp later than the maximum timestamp 328 and contains a resource with the resource identifier of the cached resource.
[0035] FIG. 4 d is a flowchart for a method of the resource loader 310 of FIG. 3 to calculate the maximum timestamp 328 of a cached resource in accordance with an aspect of the present invention. At step 460 a loop is initiated through all of the resource containers in the ordered container list 320 . The loop of step 460 is sequential starting at a first entry in the ordered container list 320 (for example, starting at a lowest index 322 ). At step 462 , for a current resource container in the ordered container list 320 , the method determines if the current resource container is the first resource container processed by the loop. If so, the method proceeds to step 468 where the maximum timestamp 328 of the cached resource is set to be the value of the timestamp of the current resource container. If step 462 determines that the current resource container is not the first resource container processed by the loop, the method proceeds to step 464 where the method determines if the timestamp of the current resource container is greater that the maximum timestamp 328 . If so, the method proceeds to step 468 . Alternatively, the method proceeds to step 466 where the method is looped until the current container has an index which is the same as the container path index 326 of the cached resource. In this way the method of FIG. 4 d assigns a value to the maximum timestamp 328 of a newly cached resource which is the latest (highest) timestamp of all of the resource containers in the ordered container list 320 up to and including the resource container with the container path index 326 .
[0036] An aspect of the present invention will now be considered in use by way of example only with reference to FIG. 5 and FIGS. 6 a to 6 e . FIG. 5 is an illustration of an exemplary time line of changes to Java archive (jar) files and class loading operations in accordance with an aspect of the present invention. FIG. 6 a is a block diagram of a Java virtual machine (JVM) 608 for loading classes from one or more Java archive (jar) files 602 , 604 and 606 in accordance with an aspect of the present invention. Considering FIG. 6 a first, the JVM 608 includes a class loader 610 comprising a stale cache checker 611 . The class loader 610 has generally the same function as the resource loader 310 of FIG. 3 . The JVM 608 further includes a class cache 612 (analogous to the resource cache 312 ) and a classpath 614 (analogous to the resource search path 314 ) having an ordered list of jar files 620 . The class cache 612 of the JVM 608 is initially empty. The classpath 614 includes entries for three jar files: “A.jar” with an index of “1”; “B.jar” with an index of “2”; and “C.jar” with an index of “3”. For each of these jar files a resource container is illustrated. Resource container 602 represents a jar file with a container identifier 6022 of “A.jar”. Resource container 602 further has a timestamp 6024 with a value of “7”. Additionally, resource container 602 includes two classes 6026 and 6028 , each having a class identifier 60262 and 60282 with values “L” and “M” respectively. Resource container 604 represents a jar file with a container identifier 6042 of “B.jar”. Resource container 604 further has a timestamp 6044 with a value of “4”. Additionally, resource container 604 includes two classes 6046 and 6048 , each having a class identifier 60462 and 60482 with values “Q” and “R” respectively. Resource container 606 represents a jar file with a container identifier 6062 of “C.jar”. Resource container 606 further has a timestamp 6064 with a value of “5”. Additionally, resource container 605 includes two classes 6066 and 6068 , each having a class identifier 60662 and 60682 with values “T” and “U” respectively.
[0037] Referring now to FIG. 5 , a example timeline comprising eighteen points in time is illustrated with events for these points in time indicated by a bold arrow with associated description. The time line and events occurring at particular points in time will now be used to demonstrate an aspect of the present invention in use. At time “4” the resource container 604 with the identifier “B.jar” is created. Hence, resource container 604 has a timestamp 6024 of “4”. Similarly, at time “5” the resource container 606 with the identifier “C.jar” is created. Hence, resource container 606 has a timestamp 6064 of “5”. Also, at time “7” the resource container 602 with the identifier “A.jar” is created. Hence resource container 602 has a timestamp 6024 of “7”.
[0038] At time “10” the JVM 608 instructs the classloader 610 to load a class with the identifier “R”. Referring to the method of FIG. 4 a to load a resource with a required resource identifier, at step 402 the classloader 610 determines if a class with the required class identifier is stored in the class cache 612 . The class cache 612 is empty so the method proceeds to step 406 where the method loads a class with the required class identifier from the resource containers 602 , 604 and 606 using the method of FIG. 4 b . Turning, therefore, to the method of FIG. 4 b for loading a class with the class identifier “R”, at step 420 a loop is initiated through all of the resource containers in the ordered list of jar files 620 . Starting at the first jar file with an index of “1” (“A.jar”), the method determines at step 422 if the corresponding resource container 602 with the identifier “A.jar” contains a class with the class identifier “R”. Resource container 602 does not contain a class with the class identifier “R” and so the method proceeds to step 428 where the method loops back to step 420 for the next jar file in the ordered list of jar files 620 . For the next jar file with an index of “2” (“B.jar”) the method determines at step 422 if the corresponding resource container 604 with the identifier “B.jar” contains a class with the class identifier “R”. Resource container 604 does contain the class 6048 with the identifier “R” and so the method proceeds to step 424 where the class loader 610 loads class 6048 from resource container 604 . Subsequently, at step 426 , the class loader 610 creates a cached copy 6122 of class 6048 in the class cache 612 . FIG. 6 b is a block diagram of the JVM 608 of FIG. 6 a with the class 6048 “R” loaded and cached in the class cache 612 in accordance with an aspect of the present invention. The cached copy 6122 of the class 6048 has a class identifier 61222 with a value of “R”, and a classpath index 61224 with a value of “2”. The classpath index 61224 is the index of the resource container 604 in the ordered list of jar files 620 . Since resource container 604 has an identifier of “B.jar” and “B.jar” has an index of “2” in the ordered list of jar files 620 , the classpath index 61224 of the cached class 6122 has a value of “2”. The class 6122 in the class cache 612 also has a maximum timestamp 61226 with a value of “7”. This is determined using the method of FIG. 4 d as being the latest (highest) timestamp of all of the resource containers in the ordered list of jar files 620 up to and including the jar file with an index of the classpath index 61224 . The jar file in the ordered list of jar files 620 with an index of the classpath index 61224 of “2” is “B.jar”. Thus, the maximum timestamp is the latest timestamp of the resource containers with identifiers “A.jar” and “B.jar”, these being the resource containers with an index in the ordered list of jar files 620 up to and including the value “2”. The latest timestamp of the resource containers with identifiers “A.jar” and “B.jar” is the timestamp of resource container 602 which is “7”. Hence, the maximum timestamp 61226 has the value “7”.
[0039] Referring again to FIG. 5 , at time “12” a new class is added to resource container 602 (“A.jar”) with a class identifier of “R”. FIG. 6 c is a block diagram of the JVM 608 of FIG. 6 b with a new class 6029 “R” added to the “A.jar” Java archive (jar) file in accordance with an aspect of the present invention. FIG. 6 c further includes a change to the value of the timestamp 6024 of resource container 602 to reflect the change to the resource container at time point “12”. Further in FIG. 5 , at time “14” the JVM 608 instructs the classloader 610 to once again load a class with the identifier “R”. Referring to the method of FIG. 4 a to load a resource with a required resource identifier, at step 402 the classloader 610 determines if a class with the required class identifier “R” is stored in the class cache 612 . Class 6122 with the class identifier 61222 “R” is stored in the class cache 612 so the method proceeds to step 404 . At step 404 the stale cache checker 611 determines if class 6122 in the class cache 612 is stale using the method of FIG. 4 c.
[0040] Turning, therefore, to the method of FIG. 4 c to determine if the cached class 6122 is stale, at step 440 a loop is initiated through all of the jar files in the ordered list of jar files 620 , starting with “A.jar” corresponding to resource container 602 . At step 442 the method determines if the timestamp 6024 of resource container 602 is greater than the maximum timestamp 61226 of the cached class 6122 . The timestamp 6024 has a value of “12” (see FIG. 6 c ) and the maximum timestamp 61226 has a value of “7”. Thus, the timestamp of resource container 602 is greater than the maximum timestamp 61226 of cached class 6122 and the method proceeds to step 444 . At step 444 the method determines if resource container 602 contains a class with a class identifier value of “R” (corresponding to the class identifier 61222 of the cached class 6122 ). Resource container 602 does contains a class 6029 with the class identifier 60292 of “R” and so the method proceeds to step 446 . At step 446 the method of FIG. 4 c concludes that the class 6122 is stale.
[0041] Thus, returning to the method of FIG. 4 a , step 404 determined that class 6122 is stale and the method proceeds to step 406 where the method loads a class with the required class identifier from the resource containers 602 , 604 and 606 using the method of FIG. 4 b . Turning, therefore, to the method of FIG. 4 b for loading a class with the class identifier “R”, at step 420 a loop is initiated through all of the resource containers in the ordered list of jar files 620 . Starting at the first jar file with an index of “1” (“A.jar”), the method determines at step 422 if the corresponding resource container 602 with the identifier “A.jar” contains a class with the class identifier “R”. Resource container 602 does contain a class 6029 with the class identifier “R” and so the method proceeds to step 424 where the class loader 610 loads class 6029 from resource container 602 . Subsequently, at step 426 , the class loader 610 creates a cached copy 6124 of class 6029 in the class cache 612 . FIG. 6 d is a block diagram of the JVM 608 of FIG. 6 c with the class 6029 “R” loaded and cached in the class cache 612 in accordance with an aspect of the present invention. The cached copy 6124 of the class 6029 has a class identifier 61242 with a value of “R”, and a classpath index 61244 with a value of “1”. The classpath index 61244 is the index of the resource container 602 in the ordered list of jar files 620 . Since resource container 602 has an identifier of “A.jar” and “A.jar” has an index of “1” in the ordered list of jar files 620 , the classpath index 61244 of the cached class 6124 has a value of “1”. The class 6124 in the class cache 612 also has a maximum timestamp 61246 with a value of “12”. This is determined using the method of FIG. 4 d as being the latest (highest) timestamp of all of the resource containers in the ordered list of jar files 620 up to and including the jar file with an index of the classpath index 61244 . The jar file in the ordered list of jar files 620 with an index of the classpath index 61244 of “1” is “A.jar”. Thus, the maximum timestamp is the timestamp of the resource containers with identifier “A.jar”, this being the resource container with an index in the ordered list of jar files 620 up to and including the value “1”. Hence, the maximum timestamp 61246 has the value “12”.
[0042] Referring again to FIG. 5 , at time “16” a new class is added to resource container 606 (“C.jar”) with a class identifier of “R”. FIG. 6 e is a block diagram of the JVM 608 of FIG. 6 b with a new class 6069 “R” added to the “C.jar” Java archive (jar) file in accordance with an aspect of the present invention. FIG. 6 e further includes a change to the value of the timestamp 6064 of resource container 606 to reflect the change to the resource container at time point “16”. Further in FIG. 5 , at time “18” the JVM 608 instructs the classloader 610 to once again load a class with the identifier “R”. Referring to the method of FIG. 4 a to load a resource with a required resource identifier, at step 402 the classloader 610 determines if a class with the required class identifier “R” is stored in the class cache 612 . Class 6124 with the class identifier 61242 “R” is stored in the class cache 612 so the method proceeds to step 404 . At step 404 the stale cache checker 611 determines if class 6124 in the class cache 612 is stale using the method of FIG. 4 c.
[0043] Turning, therefore, to the method of FIG. 4 c to determine if the cached class 6124 is stale, at step 440 a loop is initiated through all of the jar files in the ordered list of jar files 620 , starting with “A.jar” corresponding to resource container 602 . At step 442 the method determines if the timestamp 6024 of resource container 602 is not greater than the maximum timestamp 61246 of the cached class 6122 . The timestamp 6024 has a value of “12” (see FIG. 6 e ) and the maximum timestamp 61246 also has a value of “12”. Thus, the timestamp of resource container 602 is not greater than the maximum timestamp 61246 of cached class 6122 and the method proceeds to step 448 . At step 448 the method determines if the index of the resource container 602 in the ordered list of jar files 620 is the same as the classpath index 61244 of the cached class 6124 . The resource container 602 has container identifier “A.jar” which has an index of “1” in the ordered list of jar files 620 . The classpath index 61244 of the cached class 6124 also has a value of “1”. The method therefore proceeds to step 450 where the method determines that cached class 6124 is not stale.
[0044] Thus, returning to the method of FIG. 4 a , step 404 determined that class 6122 is not stale and at step 408 the class loader 610 loads the class 6124 with the class identifier 61242 of “R” from the class cache 612 . Thus, the examples charted by the timeline of FIG. 5 illustrate how aspects of the present invention illustrated in FIG. 3 and FIGS. 4 a to 4 d provide a mechanism for detecting stale resources in a resource cache without a need to refresh the resource cache and without a need to search through all resource containers in a resource search path to verify that the resource has not been updated. The inclusion of a container path index 326 provides an indicator of how much of the ordered container list 320 must be processed to determine if a cached resource 316 is stale. Further, the maximum timestamp 328 allows a determination that a cached resource is out of date.
[0045] The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0047] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
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A method loads a resource in a software application. The software application comprises an ordered search path identifying at least one of a plurality of resource containers. Each of the resource containers includes a timestamp and an index in the ordered search path. The method includes loading a resource from an originating resource container, the originating resource container having an index in the ordered search path, identifying a set of resource containers in the ordered search path, each of the set of resource containers having an index less than or equal to the index of the originating resource container, generating a cached resource as a copy of the loaded resource, the cached resource comprising the index of the originating resource container and a cached resource timestamp, the cached resource timestamp corresponding to a maximum timestamp of the resource containers in the set of resource containers, and marking the cached resource as invalid in response to a determination that a resource container in the set of resource containers has a timestamp later than the cached resource timestamp, and the identified resource container comprises the cached resource.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of co-pending U.S. Provisional Patent Application Serial No. 60/160,612, filed Oct. 20, 1999.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of Grant Nos. HL27763 and HL47574 awarded by the National Institute of Health.
FIELD OF THE INVENTION
The present invention is directed to a method for inhibiting either iNOS or COX-2, or both in mammals using flavone compounds. The present invention is also directed to a method of activating K + channels in mammals; as well as methods for treating septic shock, treating or preventing aneurysm, inhibiting expression of angiotensin converting enzyme and reducing inflammation and related pathological changes using these compounds. Presently preferred compounds are oroxylin A (5,7-dihydroxy-6-methoxy flavone) and wogonin (5,7-dihydroxy-8-methoxy flavone).
BACKGROUND OF THE INVENTION
COX-2
Septic shock and multiple-organ failure are catastrophic consequences of an invasive infection. Septic shock has been estimated to occur in more than 500,000 cases per year in the United States alone. Septic shock is the most common cause of death in non-coronary intensive care units. As more antibiotic-resistant strains of bacteria evolve, the incidence of septic shock is expected to increase. Overall mortality rates from septic shock range from 30% to 90%. Aggressive antibiotic treatment and timely surgical intervention are the main therapies, but in many cases are insufficient. The search for new drug therapies has not been successful. For example, only small, but not statistically significant improvements in 28-day mortality compared to placebo was found when the compound Deltibant was administered to human patients suffering systemic inflammatory response syndrome and presumed sepsis (R. Stone, J. Am. Med Assoc., vol. 277, pp. 482-487 (1997)).
Lipopolysaccharide (LPS) is believed to be the principal agent responsible for inducing sepsis syndrome, which includes septic shock, systemic inflammatory response syndrome, and multi-organ failure. Sepsis is a morbid condition induced by a toxin, the introduction or accumulation of which is most commonly caused by infection or trauma. The initial symptoms of sepsis typically include chills, profuse sweating, irregularly remittent fever, prostration and the like; followed by persistent fever, hypotension leading to shock, neutropenia, leukopenia, disseminated intravascular coagulation, acute respiratory distress syndrome, and multiple organ failure.
LPS, also know as endotoxin, is a toxic component of the outer membrane of Gram-negative microorganisms (e.g., Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa ). Compelling evidence supports the toxic role of LPS; all pathophysiological effects noted in humans during Gram-negative sepsis can be duplicated in laboratory animals by injection of purified LPS. The mechanism by which LPS activates responsive cells is complex and not fully understood. The host response to Gram-negative bacterial infection depends on effector cell recognition of the bacteria, LPS, or both and involves both serum proteins and cell membrane receptors. When bacteria and LPS are removed via endocytosis and phagocytosis by reticuloendothial cells, concomitant activation of the host immune response by LPS results in the secretion of cytokines by activated macrophages, which in turn can trigger the exaggerated host responses associated with septic shock.
The normal immune response begins when neutrophils squeeze through the blood-vessel walls searching for bacterial pathogens in the surrounding tissue. Neutrophils can kill bacteria directly by releasing toxic chemicals or enzymes, such as elastase or collagenase. The neutrophils also attract other leukocytes to the area, including lymphocytes, macrophages, and monocytes, the last two of which release powerful immune-response activators called cytokines. The cytokines, in turn, stimulate more immune cell activity and increase the number of cells coming to the area by making the blood-vessel wall more permeable. Then, as the number of bacteria decreases, other cytokines signal to bring the normal immune response to an end.
If the cutoff mechanism fails, however, sepsis can begin. In sepsis, humoral and cellular mediators cascade in a process that becomes at least temporarily independent of the underlying infection. Excess neutrophils and macrophages are drawn to the site of infection, releasing excess immune-stimulating cytokines, eventually triggering the release of substances that damage the blood-vessel wall. More monocytes and macrophages come to the site and release more cytokines. Eventually, the blood vessels are so damaged and leaky that blood pressure falls and the blood can no longer supply nutrients to the body's organs. Entire organs can begin to shut down. Many patients die after losing the function of two or more organs.
Two cytokines that play an important role in sepsis are interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF alpha). These two polypeptides can raise body temperature, increase the expression for adhesion molecules on neutrophils and endothelial cells (promoting adhesion of leukocytes), stimulate the production of vasodilating prostaglandins (thus increasing the permeability of blood vessels), trigger the release of other cytokines, stimulate neutrophils, and activate fibroblasts. All these processes enhance the probability of organ failure seen in severe septicemia. Drug therapies that target only one of these two cytokines have proved ineffective (See Stone). Drug therapies that are effective against general inflammatory responses have not proven to be effective against the cascading acute inflammation that produces septicemia. There is a need for drugs that can inhibit this cascading system at the beginning steps of production of IL-1 and TNF alpha.
Other important cytokines, chemokines, and other proteins having proinflammatory activity include interferon-gamma (IFN gamma), interleukin-6 (IL-6), macrophage chemotactic protein (MCP), inducible nitric oxide synthetase (iNOS), mitogen-activated protein kinases (MAPKs), macrophage inflammatory protein, KC/CINC (growth related gene), tissue factor (TF), granulocyte-macrophage-colony stimulating factor (Gm-CSF) and phosphotyrosine phosphatase (PTPase).
Prostaglandins are also involved in the proinflammatory response; e.g., prostaglandins increase the permeability of the blood-vessel wall. Cyclooxygenase (COX; prostaglandin endoperoxide synthase) catalyzes the conversion of arachidonic acid to prostaglandin (PG) endoperoxide (PGH2), which is the rate limiting step in prostaglandin biosynthesis. Two isoforms of COX have been cloned from animal cells: the constitutively expressed COX-1, and the mitogen-inducible COX-2. Prostaglandins produced as a result of the activation of COX-1 may have physiological functions such as the antithrombogenic action of prostacyclin released by the vascular endothelium, and the cytoprotective effect of PGs produced by the gastric mucosa. However, COX-2 is the enzyme expressed following the activation of cells by various proinflammatory agents including cytokines, endotoxin and other mitogens. These observations suggest that COX-2 instead of COX-1 may be responsible for inducing production of the prostaglandins involved in inflammation. Only a few pharmacological agents that suppress the expression of COX-2 without affecting COX-1 have been identified, for example, glucocorticoids and radicicol. However, these agents have undesirable side effects.
There is a need for compounds that selectively inhibit COX-2, and that act as potent anti-inflammatory agents, with minimal side effects. To prevent septicemia, such a compound should also inhibit the production of a wide variety of proinflammatory cytokines, especially TNF alpha and IL-1, chemokines, and protein-tyrosine kinases.
Nitric Oxide (NO) was originally identified in vascular endothelial cells (Palmer et al. (1987) Nature 327:524-526 and Palmer et al.(1988) Nature 333:664-666) and has been identified as being identical to endothelium-derived relaxing factor (Moncada et al. (1989) Biochem. Pharmacol. 38:1709-1715; Furchgott (1990) Acta Physiol. Scand. 139:257-270 and Iganarro (1990) Annu. Rev. Phamacol. Toxicol. 30:535-560). Besides endothelial cells, NO formation has been demonstrated in macrophages (Hibbs et al. (1987) Science 235:473-476 and Marletta et al. (1988) Biochemistry 27:8706-8711), neutrophils (McCall et al. (1989) Biochem. J. 262:293-297; Salvemini et al. (1989) Proc. Natl. Acad. Sci. USA 86:6328-6332 and Wright et al. (1989) Biochem. Biophys. Res. Commun. 160:813-819), some tumor cells (Amber et al. (1988) J. Leuk. Biol. 44:58-65), adrenal glands (Palacios et al. (1989) Biochem. Biophys Res. Commun. 165:802-809). Kupffer cells (Billiar et al. (1989) J. Exp. Med. 169:1467-1472) and in brain tissue (Garthwaite et al. (1988) Nature 336:385-388; Knowles et al. (1989) Proc. Natl. Acad. Sci.USA 86:5159-5162 and Bredt and Snyder (1989) Proc. Natl. Acad. Sci. USA 86:9030-9033).
Endothelium-derived NO relaxes the smooth muscles of blood vessels (Palmer et al. (1987) Nature 327:524-526 and Ignarro et al. (1987) Proc. Natl. Acad. Sci. USA 84:9265-9269) and inhibits platelet adhesion (Radomski et al. (1987) Biochem. Biophys. Res. Commun., 148:1482-1489). NO production by cocultures of Kupffer cells and hepatocytes mediates inhibition of hepatocyte protein synthesis (Billar et al. (1989) J. Exp. Med. 169:1467-1472). NO is responsible for mediating the cytotoxic effects of macrophages and neutrophils (Hibbs et al. 91987) J. Immunol. 138:550-556). NO has also been shown to be a major neuronal messenger in the brain (Bredt and Snyder (1989) Proc. Natl. Acad. Sci. USA 86:9030-9033). The mediation of functions of tissues as diverse as the brain, endothelium and blood cells indicates a wide-spread role for NO as a messenger molecule.
NO is formed by nitric oxide synthetase (NOS) from L-arginine with stoichiometric formation of L-citrulline. Studies have shown that a guanidino nitrogen of L-arginine is used to form NO (Iyengar et al. (1987) Proc. Natl. Acad. Sci. USA 84:6369-6373; Palmer et al. (1988) Nature 333:664-666 and Marietta et al. (1988) Biochemistry 27:8706-8711).
The formation of NO appears to involve the same or similar enzyme in brain and endothelial cells but a different enzyme in macrophages. The brain-endothelium enzyme has been found to require calcium and calmodulin for activity (Bredt and Snyder (1990) Proc. Natl. Acad. Sci. USA 87:682-685). The macrophage enzyme does not require calcium-calmodulin but does require tetrahydrobiopterin for activity (Tayeh and Marietta (1989) J. Biol. Chem. 264:19654-19658; Soo Kwon et al. (1989) J. Biol. Chem. 264:20496-20501).
The brain (i.e., calmodulin-dependent) NOS enzyme has been purified to homogeneity from rat brain, revealing a 150,000 kD protein (Bredt and Snyder (1990) Proc. Natl. Acad. Sci. USA 87:682-685).
In addition to the differences between NOS activities in brain and endothelial cells as compared to macrophages, the regulation of NOS expression appears to differ as well. The synthesis of NO does not occur in macrophages unless they have been exposed to endotoxin (e.g., bacterial lipopolysaccharide) or cytokine (e.g., interferon-gamma, -beta or alpha, tissue necrosis factor-alpha or -beta). However, in the brain and vascular endothelium, NOS is present without exposure to inducing agents (Knowles et al. (1990) Biochem. J. 270:833-836). The arginine derivative L-N-omega-nitroarginine (NO 2 Arg) has been described as being a competitive inhibitor of NOS (Moore (1990) Br. J. Pharmacol. 99:408-412).
NO has been demonstrated to mediate neuronal relaxation of intestines (Bult et al. (1990) Nature 345:346-347; Gillespie et al. (1989) Br. J. Pharmacol. 98:1080-1082 and Ramagopal and Leighton (1989) Eur. J. Pharmacol. 174:297-299) and to mediate stimulation by glutamate of cGMP formation (Bredt and Snyder (1989) Proc. Natl. Acad. Sci. USA 86:9030-9033). Glutamate, the major excitatory neurotransmitter in the brain, acts through several receptor subtypes, some of which stimulate the formation of cGMP (Ferrendelli et al. (1974) J. Neurochem. 22:535-540). Glutamate, acting at N-methyl-D-aspartate (NMDA) subtype of receptors, is responsible for neurotoxic damage in vascular strokes. Selective antagonists of NMDA glutamate receptors prevent neuronal cell death in animal models of hypoxic-ischemic brain injury (Choi (1990) J. Neurosci. 10:2493-2501). Glutamate neurotoxicity has also been implicated in neurodegenerative disorders such as Alzheimer's and Huntington's diseases (Choi (1990) J. Neurosci. 10:2493-2501 and Meldrum and Garthwaite (1990) Trends in Pharmacol. Sci. 11:379-387).
As decribed above, nitric oxide (NO) has been shown to be an important regulatory molecule in diverse physiological functions such as vasodilation, neural communication and host defense. Molecular cloning and sequencing analysis have revealed the existence of at least three main types of NOS isoforms. NOS is present in the vascular endothelium (eNOS); in central and peripheral neurons (nNOS); and is also constitutive (cNOS). Activation is Ca +2 -dependent. Continuous release of NO by cNOS keeps the vasculature in an active state of vasodilation. Various agonists such as bradykinin and acetylcholine have been shown to trigger cNOS-mediated NO production through increasing intracellular Ca +2 . NOS in macrophages and hepatocytes, on the other hand, is inducible (iNOS) and its activation is Ca +2 -independent (Duval et al., Mol. Pharmacol. 50: 277-84, 1996, Yuan, T., Febs. Lett. 431:210-4, 1998). After exposure to endotoxin and/or cytokines, iNOS can be induced in various cells such as macrophages, Kupffer cells, smooth muscle cells and hepatocytes. The induced iNOS catalyzed the formation and release of a large amount of NO, which play a key role in the pathophysiology of a variety of diseases including septic shock (Pedoto, A. et al., Crit. Care Med. 26:2021-8, 1998). NO production catalyzed by iNOS therefore may reflect the degree of inflammation and provides a measure by which effects of drugs on the inflammatory process can be assessed.
It is known that inhibition of either iNOS or COX-2 enzymes prevents aneurysm (Miralles, M. et al. J. Vasc. Surg . May 1999, Vol. 5, pp. 884-892; and Fukuda, S. Circulation , May 2000, 101 (21) pp. 2532-2538).
Expression of cyclooxygenase-2 (COX-2) in various tissue preparations following LPS treatment has also been reported (Quan, N. et al., Brain Res. 802:189-197; Lee, S. H. et al., J. Biol. Chem. 267: 25934-25938, 1992). This enzyme also is considered to play a major role in inflammatory process by catalyzing the production of prostaglandins.
Compounds which inhibit iNOS or COX-2 would be useful anti-inflammatory agents as has been described above; and a compound which inhibits or prevents induction of both enzymes at the same time should be particularly useful. To date, compounds which inhibit both enzymes have not been identified.
Therefore, one object of the invention is to identify anti-inflammatory agents. A further object of the invention is to identify compounds which inhibit induction of both iNOS and COX-2.
Potassium Channels
Four types of K + channels have been described in vascular and nonvascular smooth muscle. These are: (1) calcium-activated (2) voltage-dependent (also called delayed rectifier) (3) ATP-sensitive and (4) inwardly rectifying K + channels. Calcium-activated K + channels (K Ca channels) have been found in virtually every type of smooth muscle. These K + channels are activated by increasing levels of intracellular calcium. They may also be activated by membrane depolarization, although this mechanism also requires calcium at physiologic membrane potentials. Calcium-activated K + channels are thought to be the most abundant in vascular smooth muscle, with up to 10 4 channels estimated to be present per cell (Nelson and Quayle, “Physiological Roles and Properties of Potassium Channels in Arterial Smooth Muscle”, Am. J. Physiol. 268 (4Pt 1): C799-822, 1995).
One of the important physiological roles of K Ca channels is regulation of smooth muscle or myogenic tone. Elevation of intravascular pressure depolarizes smooth muscle cells in resistance arteries and causes vasoconstriction. This tone has been referred to as “myogenic tone” and is a major contributor to peripheral resistance. K Ca channels play an important role in the control of myogenic tone. It has been proposed that pressure-induced membrane depolarization and increases in intracellular Ca 2+ activate K Ca channels. Activation of K Ca channels would increase K + efflux, which would counteract the depolarization and constriction caused by pressure and vasoconstrictors. Activation of K Ca channels acts as a negative feedback mechanism to limit vasoconstriction.
K Ca channels are regulated by endogenous vasoactive substances. Most vasoconstrictors (e.g. norepinephrine, angiotensin II, endothelin, and serotonin) depolarize vascular smooth muscle. It is conceivable that inhibition of K Ca channels contributes to this membrane depolarization. Recently, angiotensin II and a thromboxane A2 agonist (U-46619) have been shown to inhibit K Ca channels from coronary artery smooth muscle. Muscarinic receptor stimulation has been shown to inhibit K Ca channels in airway and colonic smooth muscle. (Faraci and Sobey, “Role of Potassium Channels in Regulation of Cerebral Vascular Tone”, J. Cereb. Blood Flow Metab. 18 (10): 1047-63, 1998).
Activation of K Ca channels would tend to hyperpolarize smooth muscle and lead to muscle relaxation. β-Adrenergic stimulation activates K Ca channels in airway smooth muscle cells and thus may contribute to β-adrenergic bronchodilation. This activation of K CA channels in airway and coronary artery smooth muscle cells appears to be caused by phosphorylation mediated by an adenosine 3′,5′-cyclic monophosphate (cAMP)-dependent protein kinase as well as a direct G protein pathway. Recent evidence indicates that guanosine 3′,5′-cyclic monophosphate (cGMP)-dependent protein kinase can also activate K CA channels in smooth muscle cells isolated from cerebral and coronary arteries. Nitric oxide can activate cGMP-dependent protein kinase through stimulation of guanylyl cyclase and elevation of cGMP. Furthermore, nitric oxide has also been reported to directly activate K CA channels in aortic smooth muscle. Vasorelaxation of some vascular beds (e.g., mesenteric and cerebral arteries) in response to nitric oxide appears to involve activation of K CA channels.
Like calcium-activated K + channels, voltage-dependent K + channels are activated in response to membrane depolarization, but this process occurs independent of the intracellular calcium concentration. Because both voltage-dependent and calcium-activated K + channels are activated by depolarization, 4-aminopyridine (4-AP) can be used to distinguish responses mediated by either channel. Tetraethylammonium (TEA) is a poor inhibitor of voltage-dependent K + channels unless very high concentrations are used. The estimated number of voltage-dependent K + channels per cell in arteries is about 10 3 .
Compared with other K + channels, much less is known about the functional importance of voltage-dependent K + channels. It has been suggested that activity of voltage-dependent K + channels influence resting cerebral vascular tone. These K + channels are also activated by increases in arterial blood pressure. Recent studies suggest that activation of voltage-dependent K + channels may contribute to mechanisms that produce cerebral vasorelaxation in response to NO and endothelium-derived hyperpolarizing factor (EDHF) (Faraci and Sobey, 1998).
There are three physiological roles of K v channels which include: (1) Repolarization of the action potential. Despite the wide distribution of K v channels, relatively few studies have been conducted on the physiological role of this channel in arterial smooth muscle. Because the channel is activated by depolarization, it may be involved in action potential repolarization in electrically excitable smooth muscle preparations such as the portal vein, and this is a principal function of the channel in other excitable cells, including neurons and cardiac muscle. However, most arteries generally respond to stimuli with graded membrane potential changes, and therefore K v channels are unlikely to be involved in action potential repolarization in these arteries. (2) Regulation of the membrane potential. K v channels provide an important K + conductance in the physiological membrane potential range in arteries that do not generate action potentials. Activation of K v channels by membrane depolarization, e.g., in response to pressurization or vasoconstrictors, may limit membrane depolarization. K v channels may also be directly modulated by vasoconstrictors and vasodilators, and a 4-AP-sensitive K + current is inhibited by a histamine H 1 receptor agonist in coronary arteries. It was suggested that inhibition of the 4-AP-sensitive current occurred as a result of increased intracellular Ca 2+ concentration through intracellular C 2+ release. A related observation is that intracellular Mg 2+ (10 mM) inhibits K v currents positive to −15 mV in arterial smooth muscle cells. (3) hypoxic pulmonary vasoconstruction. Pulmonary arteries constrict in hypoxia, which minimizes blood perfusion in poorly ventilated areas of the lung. This hypoxic vasoconstriction contrasts with the hypoxic vasodilation seen in many small systemic arteries and which may involve an activation of other types of K + channels. During hypoxia, pulmonary arteries depolarize and may generate action potentials. The resulting pulmonary vasoconstriction is abolished by removal of extracellular Ca 2+ and by Ca 2+ channel antagonists such as verapamil, suggesting that Ca 2+ entry through voltage-dependent Ca 2+ channels is important in the hypoxic response.
Recent studies suggest a role for K + channels in hypoxia-induced membrane depolarization and constriction. K + channel inhibitors such as TEA + and 4-AP increase tone in isolated pulmonary vessels and increase perfusion pressure in the isolated perfused lung. Thus K + channels contribute to the membrane potential in pulmonary arteries as they do in systemic arteries. Because K + channels regulate the membrane potential of pulmonary smooth muscle, hypoxia may depolarize by inhibiting K + channels. It has recently been directly shown that hypoxia inhibits voltage-activated K + currents in these arteries. The voltage dependence of the hypoxia-sensitive channel suggests that it is a member of the K v or K Ca families. A number of mechanisms have been proposed to link hypoxia to channel inhibition. K Ca channels in rat pulmonary arterial myocytes are activated by intracellular ATP. Therefore a fall in intracellular ATP during hypoxia may inhibit this channel. However, the ATP connection in smooth muscle cells is generally well conserved during hypoxia. Cellular redox status has also been proposed as the link between hypoxia and K + channel activity, and an increase in cellular reducing agents causes inhibition of K + channels in pulmonary arteries.
One key characteristic of ATP-sensitive K + channels (K ATP ) is that their activity may reflect the metabolic state of the cell. These K + channels are sensitive to intracellular ATP, which inhibits channel activity. Dissociation of ATP from the channel results in channel opening and membrane hyperpolarization. Other metabolically related stimuli, including reductions in PO 2 or pH, also open the channel and produce vasorelaxation. It is estimated that a few hundred ATP-sensitive K + channels are present per cell in arteries. The number is much less than that for calcium-activated K + channels.
K ATP channels have several physiological roles. The channel is activated by a number of vasodilators, and the associated membrane hyperpolarization causes part of the resulting vasodilation in many cases. The K ATP channel may also be inhibited by vasoconstrictors which would tend to cause depolarization and constriction. The channel is involved in the metabolic regulation of blood flow; it is activated in conditions of increased blood demand, e.g., in hypoxia, either by release of vasodilators from the surrounding tissue or as a direct result of hypoxia on the vascular smooth muscle cells. Finally, the channel may be active in the resting state, because inhibition of K ATP channels can lead to increased resistance to blood flow in some vascular beds.
Inwardly rectifying K + channels (K IR channels) are present in a variety of excitable and nonexcitable cells, including some arterial smooth muscle cells. The name of this channel comes from the observation that the membrane potential is controlled, e.g., by voltage clamp of the cell, inward currents through the K IR channel (movement of K + from the extracellular solution into the cell) are larger than outward currents. This is because the K IR channel is activated by membrane hyperpolarization, in contrast to K V and K Ca channels, which are activated-by membrane depolarization.
Although outward currents through the K IR channel are small, in most physiological situations the cell membrane potential is positive to the E K , providing an electrochemical gradient for K + to leave the cell. The K IR channel therefore normally conducts an outward hyperpolarizing membrane current. From a physiological standpoint, these small outward currents are therefore of considerable interest. Outward K + movement through the cardiac muscle K IR channel is limited by voltage-dependent channel closure on membrane depolarization and may also involve block of outward current through the channel by intracellular Mg 2+ . However, the role of intracellular Mg 2+ is complex because channels that are blocked are unable to undergo voltage-dependent closure.
The physiological roles of the K IR channel in cells other than smooth muscle include regulating the resting membrane potential, preventing membrane hyperpolarization to values more negative than the E k by the electrogenic Na + -K + -ATPase, and minimizing cellular K + loss and therefore energy expenditure during sustained membrane depolarization. The roles of the K IR channel in arterial smooth muscle are incompletely understood but may include some of the functions such as mediates K + -induced dilations and regulation of membrane potential.
In summary, activation of K + channels in arterial smooth muscle cells can increase blood flow and lower blood pressure through vasodilation. Inhibition of K + channels in arterial smooth muscle leads to vasoconstriction. Four types of K + channels (K V , K Ca , K ATP and K IR channels) have been identified to regulate the membrane potential of vascular and nonvascular smooth muscle cells.
K Ca channels in arterial smooth muscle cells respond to changes in intracellular Ca 2+ to regulate membrane potential. K Ca channels appear to play a fundamental role in regulating the degree of intrinsic tone of resistance arteries. These channels help regulate arterial responses to pressure and vasoconstrictors.
K V channels regulate membrane potential in response to depolarizing stimuli, and these channels may be involved in hypoxia-induced membrane depolarization in the pulmonary vasculature.
K ATP channels are targets of a number of vasodilating stimuli, including hypoxia and adenosine. A variety of antihypertensive drugs (e.g., minoxidel sulfate, diazoxide, lemakalim, pinacidil) act through activation of K ATP channels. Pathological conditions such as hypotension associated with septic shock may involve excessive activation of K ATP channels.
K IR channels appear to mediate external K + -induced hyperpolarizations and dilations of resistance arteries and thus provide a mechanism for linking the metabolism of surrounding cells (e.g., neurons) to blood flow.
All of these K + channel types may be involved in the actions of a variety of vasodilators and vasoconstrictors, and their function may be altered in diseases. K + channels in arterial smooth and nonvascular smooth muscle (such as uterine and pulmonary) muscle are important modulators of blood vessel diameter, and muscle tone. Our results indicate that oroxylin A is a Ca 2+ — activated K + channel opener, but is not a K ATP channel opener. Preliminary results further indicate that oroxylin A may activate other K + channels such as K V or K IR channels.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to methods for inhibiting expression of iNOS, COX-2, or both using a flavone and pharmaceutically acceptable salts thereof. The present invention is also directed to a method for activation of potassium channels by flavones; a method for treating septic shock with flavones; a method for inhibiting expression of angiotensin converting enzyme with flavones; a method for reducing inflammation and related diseases with flavones; and a method for treating or preventing aneurysms with flavones.
More particularly, the present invention is directed to the use of compounds of the formula I
wherein p is an integer of zero to five;
R 1 , at each occurrence, is independently selected from the group consisting of hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 6 alkenyl, C 1 -C 6 alkynyl, C 1 -C 6 alkoxy, alkenoxy, alkynoxy, thioalkoxy, aliphatic acyl, CF 3 , CN, NO 2 , OH, NH 2 , CH═NOH, SO 2 —(C 1 -C 3 alkyl), SO 3 —(C 1 -C 3 alkyl), N(C 1 -C 3 alkyl)-CO(C 1 -C 3 alkyl), C 1 -C 3 alkylamino, alkenylamino, alkynylamino, di(C 1 -C 3 alkyl)amino, COOH, C(O)O—(C 1 -C 3 alkyl), C(O)NH—(C 1 -C 3 alkyl), C(O)N(C 1 -C 3 alkyl) 2 , haloalkyl, alkoxylcarbonyl, alkoxyalkoxy, carboxaldehyde, carboxamide, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, aroyl, aryloxy, arylamino, biaryl, thioaryl, heterocyclyl, heterocycloyl, alkylaryl, aralkyl, alkylheterocyclyl, heterocyclylalkyl, sulfonamido, carbamate, aryloxyalkyl and C(O)NH(benzyl);
R 2 , R 4 and R 6 are each independently selected from the group consisting of hydrogen, C 1 -C 6 alkyl, C 1 -C 6 alkenyl, C 1 -C 6 alkynyl, C 1 -C 6 alkoxy, alkenoxy, alkynoxy, thioalkoxy, aliphatic acyl, CF 3 , CN, NO 2 , OH, NH 2 , CH═NOH, SO 2 —(C 1 -C 3 alkyl), SO 3 —(C 1 -C 3 alkyl), N(C 1 -C 3 alkyl)-C(O)(C 1 -C 3 alkyl), C 1 -C 3 alkylamino, alkenylamino, alkynylamino, di(C 1 -C 3 alkyl)amino, haloalkyl, alkoxylcarbonyl, alkoxyalkoxy, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, aroyl, aryloxy, arylamino, biaryl, thioaryl, alkylaryl, aralkyl, sulfonyl, heterocyclyl, heterocycloyl, alkylheterocyclyl, heterocyclylalkyl, sulfonamido, halogen and aryloxyalkyl; and
R 3 and R 5 are each independently selected from the group consisting of hydrogen, C 1 -C 6 alkyl, alkenyl, alkynyl, aryl, aralkyl, biaryl, heterocyclyl, heterocycloyl, alkylheterocyclyl, heterocyclylalkyl, cyanomethyl, cycloalkyl, cycloalkenyl and cycloalkylalkyl;
wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are unsubstituted or substituted with at least one electron donating or electron withdrawing group;
and pharmaceutically acceptable salts thereof in the methods described above. Presently preferred flavones are 5,7-dihydroxy-6-methoxy flavone (oroxylin A, wherein p is zero, R 2 , R 3 , R 5 and R 6 are hydrogen, and R 4 is methoxy for formula I above) and 5,7-dihydroxy-8-methoxy flavone (wogonin, wherein p is zero, R 2 , R 3 , R 4 and R 5 are hydrogen, and R 6 is methoxy for formula I above). For the preferred flavones, when p=zero, the phenyl ring (substituted by (R 1 ) p in formula I) is unsubstituted. The unsubstituted phenyl ring is defined herein either as when p is five and R 1 is hydrogen, or when p=0. Useful derivatives of the compounds of Formula I include esters, carbamates, animals, amides, optical isomers and pro-drugs thereof.
For the practice of any aspect of this invention, a bactericidal amount of an antibiotic may be co-administered with the flavone.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the chemical structures of the polyphenols used in the study, including two flavonoids (myricitrin, N1; oroxylin A, N2) four ellagitannins (penta-O-galloyl-β-glucopyranose, N3; woodfordin C, N4; onothein B, N5; cuphiin D1, N6), and two anthraquinones (emodin, N7; physcion, N8).
FIG. 2 shows effects of various concentrations of the FIG. 1 polyphenols on LPS-induced nitrite production in RAW264.7 macrophages.
FIG. 3 shows the inhibition of LPS-induced iNOS proteins in RAW264.7 macrophages by various concentrations of FIG. 1 compounds.
FIG. 4 shows the effects of various FIG. 1 polyphenols on LPS-induced iNOS mRNA in RAW264.7 macrophages.
FIG. 5 shows the effects of various FIG. 1 polyphenols on expression of COX-2 mRNA and protein in RAW264.7 macrophages.
FIG. 6 shows the effects of various FIG. 1 polyphenols on LPS-induced NF-kB binding in RAW264.7 macrophages.
FIG. 7 shows the detection of iNOS protein and nitrite production in LPS-treated parental RAW264.7 overexpressed RAW264.7 cells.
FIG. 8 shows the effects of oroxylin A and emodin on LPS-induced iNOS protein and nitrite production in Bcl-2/RAW-1 and Bcl-2/RAW-2 cells.
FIG. 9 shows the effects of oroxylin A and emodin on LPS-induced iNOS and. COX-2 mRNA in Bcl-2-overexpressed RAW264.7 cells.
FIG. 10 is a photomicrograph on 50 μm scale showing iNOS-immunoreactivities in Muscle (M) of background level in porcine cerebral arteries of control samples incubated in medium only (A), of significance expressed in porcine cerebral arteries incubated in medium containing LPS (10 μg/ml) (B) and of background level in porcine cerebral arteries incubated in the presence of LPS and oroxylin A (C). (A=adventitia)
FIG. 11 is a photomicrograph on 50 μm scale showing oroxylin A inhibition of LPS-induced expression of iNOS proteins in cultured primary smooth muscle cells from porcine cerebral arteries.
FIG. 12 is a Western blot analysis showing the effect of oroxylin A on iNOS expression in cultured primary smooth muscle cells isolated from porcine cerebral arteries of the circle of Willis. Cells incubated in the medium alone (lane 1) expressed some trace of iNOS proteins. Incubation in the presence of LPS (10 μg/ml) (lane 2) significantly increased iNOS proteins. The expression of iNOS proteins was decreased by oroxylin A (30 μM in lane 3, and 60 μM in lane 4) in a concentration-dependent manner. Oroxylin A at the concentrations used did not affect the expression of nNOS in each group. The total loading proteins expressed by commasie blue stain were not different among different experimental groups.
FIG. 13 shows effects of oroxylin A on L-arginine-induced relaxation in cerebral arteries without endothelial cells in the presence of active muscle tone induced by U-46619. Numbers with arrowheads indicate negative log molar concentration of L-arginine (L-Arg).
FIG. 14A shows a representative tracing showing relaxation of a cerebral arterial ring without endothelium elicited by electrical stimulation of cerebral perivascular nerves. The increased neurogenic vasodilation by oroxylin A is summarized in FIG. 14 B.
FIG. 15 shows a representative tracing illustrating concentration-dependant inhibition by oroxylin A of 9,11-dideoxy-9α,11α-epoxymethano-prostagladin F 2α (U-46619)-induced active muscle tone in a porcine cerebral artery without endothelial cells (A). In the presence of active muscle tone induced by KCl (80 mM), oroxylin A (oro A) (1-60 μM) however failed to induce sustained relaxation (B). Numbers with arrowheads indicate negative molar concentrations of oroxylin A. PPV=papaverine, 300 μM.
FIG. 16 shows a decrease in muscle tone induced by oroxylin A. Oroxylin A in a concentration-dependent manner decreased U-46619 (1 μM)-induced active tone in porcine cerebral arteries with (+EC) and without (−EC) endothelium (FIG. 16 A). The decrease in muscle tone induced by oroxylin A was not different (p>0.05) between the arteries with and those without endothelium. Two reproducible concentration-relaxant response relationships were determined on consecutive applications of oroxylin A (0.1 μM-30 μM) in the same arteries with 60 minute intervals and 3 washes between two applications. There was no significant difference (p>0.05) between the two responses. Relaxation was estimated as a percentage of maximum relaxation induced by papaverine (PPV) (300 μM). Values are means±S.E.M.; n is the number of experiments.
FIG. 17 shows a representative tracing illustrating that TEA, which further raised the basal tone, blocked the relaxation induced by oroxylin A in a cerebral arterial ring without endothelial cells.
FIG. 18 shows effects of several compounds on relaxation induced by oroxylin A in porcine cerebral arteries without endothelial cells precontracted with U46619. Relaxation was estimated as a percentage of maximum relaxation induced by papaverine (PPV, 300 μM). Values are means±S.E.M. n=5 for each drug examined. *P<0.05 and **P<0.01 indicate significant differences from the respective controls.
FIG. 19 shows the chemical structures of baicalin, baicalein and wogonin.
DETAILED DESCRIPTION OF THE INVENTION
Definition of Terms
The term “alkyl” as used herein alone or in combination refers to a straight or branched, substituted or unsubstituted chain radicals derived from saturated hydrocarbons by the removal of one hydrogen atom. Representative examples of alkyl groups include methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, and tert-butyl among others.
The term “alkenyl”, alone or in combination, refers to a straight-chain or branched-chain, substituted or unsubstituted alkenyl radical. Examples of such radicals include, but are not limited to, ethenyl, E- and Z-pentenyl, decenyl and the like.
The term “alkynyl”, alone or in combination, refers to a straight or branched chain alkynyl radical. Examples of such radicals include, but are not limited to ethynyl, propynyl, propargyl, butynyl, hexynyl, decynyl and the like.
The term “aliphatic acyl” as used herein, alone or in combination, refers to radicals of formula alkyl-C(O)—, alkenyl-C(O)— and alkynyl-C(O)— derived from an alkane-, alkene- or alkyncarboxylic acid, wherein the terms “alkyl”, “alkenyl” and “alkynyl” are as defined above. Examples of such aliphatic acyl radicals include, but are not limited to, acetyl, propionyl, butyryl, valeryl, 4-methylvaleryl, acryloyl, crotyl, propiolyl and methylpropiolyl, among others.
The term “cycloalkyl” as used herein alone or in combination refers to an aliphatic ring system having 3 to 10 carbon atoms and 1 to 3 rings, including, but not limited to cyclopropyl, cyclopentyl, cyclohexyl, norbornyl, and adamantyl among others. Cycloalkyl groups can be unsubstituted or substituted with one, two or three substituents independently selected from lower alkyl, haloalkyl, alkoxy, thioalkoxy, amino, alkylamino, dialkylamino, hydroxy, halo, mercapto, nitro, carboxaldehyde, carboxy, alkoxycarbonyl and carboxamide. “Cycloalkyl” includes cis or trans forms. The ring system may be bridged. Furthermore, the substituents may be either in exo or endo positions in bridged bicyclic systems.
The term “cycloalkenyl” as used herein alone or in combination refers to a cyclic carbocycle containing from 4 to 8 carbon atoms and one or more double bonds. Examples of such cycloalkenyl radicals include, but are not limited to, cyclopentenyl, cyclohexenyl, cyclopentadienyl and the like.
The term “cycloalkylalkyl” as used herein refers to a cycloalkyl group appended to a lower alkyl radical, including, but not limited to cyclohexyl methyl.
The term “halo” or “halogen” as used herein refers I, Br, Cl or F.
The term “haloalkyl” as used herein refers to a lower alkyl radical, to which is appended at least one halogen substituent, for example chloromethyl, fluoroethyl, trifluoromethyl and pentafluoroethyl among others.
The term “alkoxy”, alone or in combination, refers to an alkyl ether radical, wherein the term “alkyl” is as defined above. Examples of suitable alkyl ether radicals include, but are not limited to, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, sec-butoxy, tert-butoxy and the like.
The term “alkenoxy”, alone or in combination, refers to a radical of formula alkenyl-O—, provided that the radical is not an enol ether, wherein the term “alkenyl” is as defined above. Examples of suitable alkenoxy radicals include, but are not limited to, allyloxy, E- and Z-3-methyl-2-propenoxy and the like.
The term “alkynoxy”, alone or in combination, refers to a radical of formula alkynyl-O—, provided that the radical is not an -ynol ether. Examples of suitable alkynoxy radicals include, but are not limited to, propargyloxy, 2-butynyloxy and the like.
The term “carboxyl” as used herein refers to a carboxylic acid radical, —C(O)OH.
The term “carboxy” as used herein refers to —C(O)—.
The term “thioalkoxy” refers to a thioether radical of formula alkyl-S—, wherein “alkyl” is as defined above.
The term “sulfonamido” as used herein refers to —SO 2 NH 2 .
The term “carboxaldehyde” as used herein refers to —C(O)R wherein R is hydrogen.
The terms “carboxamide” or “amide” as used herein refer to —C(O)NR a R b wherein R a and R b are each independently hydrogen, alkyl or any other suitable substituent.
The term “thioalkoxy”, refers to a thioether radical of formula alkyl-S—, wherein “alkyl” is as defined above.
The term “carboxaldehyde” as used herein refers to —C(O)R wherein R is hydrogen.
The term “carboxamide” as used herein refers to —C(O)NH 2 .
The term “alkoxyalkoxy” as used herein refers to R b O—R c O— wherein R b is lower alkyl as defined above and R c is alkylene wherein alkylene is —(CH 2 ) n ′— wherein n′ is an integer from 1 to 6. Representative examples of alkoxyalkoxy groups include methoxymethoxy, ethoxymethoxy, and t-butoxymethoxy among others.
The term “alkylamino” as used herein refers to R d NH— wherein R d is a lower alkyl group, for example, ethylamino, butylamino, among others.
The term “alkenylamino” alone or in combination, refers to a radical of formula alkenyl-NH- or (alkenyl) 2 N—, wherein the term “alkenyl” is as defined above, provided that the radical is not an enamine. An example of such alkenylamino radicals is the allylamino radical.
The term “alkynylamino”, alone or in combination, refers to a radical of formula alkynyl-NH— or (alkynyl) 2 N— wherein the term “alkynyl” is as defined above, provided that the radical is not an amine. An example of such alkynylamino radicals is the propargyl amino radical.
The term “dialkylamino” as used herein refers to R e R f N— wherein R e and R f are independently selected from lower alkyl, for example diethylamino, and methyl propylamino, among others.
The term “amino” as used herein refers to H 2 N—.
The term “alkoxycarbonyl” as used herein refers to an alkoxyl group as previously defined appended to the parent molecular moiety through a carbonyl group. Examples of alkoxycarbonyl include methoxycarbonyl, ethoxycarbonyl and isopropoxycarbonyl among others.
The term “aryl” or “aromatic” as used herein alone or in combination refers to a substituted or unsubstituted carbocyclic aromatic group having about 6 to 12 carbon atoms such as phenyl, naphthyl, indenyl, indanyl, azulenyl, fluorenyl and anthracenyl; or a heterocyclic aromatic group selected from the group consisting of furyl, thienyl, pyridyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, 2-pyrazolinyl, pyrazolidinyl, isoxazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,3-triazolyl, 1,3,4-thiadiazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, 1,3,5-triazinyl, 1,3,5-trithianyl, indolizinyl, indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furanyl, 2,3-dihydrobenzofuranyl, benzo[b]thiophenyl, 1 H-indazolyl, benzimidazolyl, benzthiazolyl, purinyl, 4H-quinolizinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, 1,8-naphthridinyl, pteridinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, phenoxyazinyl, pyrazolo[1,5-c]triazinyl and the like. “Arylalkyl” and “alkylaryl” employ the term “alkyl” as defined above.
The term “aralkyl”, alone or in combination, refers to an aryl substituted alkyl radical, wherein the terms “alkyl” and “aryl” are as defined above. Examples of suitable aralkyl radicals include, but are not limited to, phenylmethyl, phenethyl, phenylhexyl, diphenylmethyl, pyridylmethyl, tetrazolyl methyl, furylmethyl, imidazolyl methyl, indolylmethyl, thienylpropyl and the like.
The term “arylamino”, alone or in combination, refers to a radical of formula aryl-NH—, wherein “aryl” is as defined above. Examples of arylamino radicals include, but are not limited to, phenylamino(anilido), naphthlamino, 2-, 3-, and 4-pyridylamino and the like.
The term “biaryl”, alone or in combination, refers to a radical of formula aryl-aryl, wherein the term “aryl” is as defined above.
The term “thioaryl”, alone or in combination, refers to a radical of formula aryl-S—, wherein the term “aryl” is as defined above. An example of a thioaryl radical is the thiophenyl radical.
The term “aroyl”, alone or in combination, refers to a radical of formula aryl-CO—, wherein the term “aryl” is as defined above. Examples of suitable aromatic acyl radicals include, but are not limited to, benzoyl, 4-halobenzoyl, 4-carboxybenzoyl, naphthoyl, pyridylcarbonyl and the like.
The term “heterocyclyl”, alone or in combination, refers to a non-aromatic 3- to 10-membered ring containing at least one endocyclic N, O, or S atom. The heterocycle may be optionally aryl-fused. The heterocycle may also optionally be substituted with at least one substituent which is independently selected from the group consisting of hydrogen, halogen, hydroxyl, amino, nitro, trifluoromethyl, trifluoromethoxy, alkyl, aralkyl, alkenyl, alkynyl, aryl, cyano, carboxy, carboalkoxy, carboxyalkyl, oxo, arylsulfonyl and aralkylaminocarbonyl among others.
The term “heterocycloyl”, as used herein refers to radicals of formula heterocyclyl-C(O)—, wherein the term “heterocyclyl” is as defined above. Examples of suitable heterocycloyl radicals include tetrahydrofuranylcarbonyl, piperidinecarbonyl and tetrahydrothiophenecarbonyl among others.
The term “alkylheterocyclyl” as used herein refers to an alkyl group as previously defined appended to the parent molecular moiety through a heterocyclyl group.
The term “heterocyclylalkyl” as used herein refers to a heterocyclyl group as previously defined appended to the parent molecular moiety through an alkyl group.
The term “aminal” as used herein refers to a hemi-acetal of the structure R h C(NR i R j )(NR k R l )— wherein R h , R i , R j , R k and R l are each independently hydrogen, alkyl or any other suitable substituent.
The term “amide” as used herein refers to a moiety ending with a —C(O)NH 2 functional group.
The term “ester” as used herein refers to —C(O)R m , wherein R m is hydrogen, alkyl or any other suitable substituent.
The term “carbamate” as used herein refers to compounds based on carbamic acid, NH 2 C(O)OH.
Use of the terms “cycloalkyl”, “heterocyclyl” “aryl”, or “alkyl” is meant to encompass substituted and unsubstituted moieties. Substitution may be by one or more groups such as alcohols, hydroxyl, nitro, cyano, carboxy, amines, heteroatoms, lower alkyl, lower alkoxy, lower alkoxycarbonyl, acyloxy, halogens, trifluoromethoxy, trifluoromethyl or any of the substituents of the preceding paragraph or any combination of aryl, alkyl, cycloalkyl or heterocyclic groups either attached directly or by suitable linkers. The linkers are typically short chains of 1-3 atoms containing any combination of —C—, —O—, —C(O)—, —NH—, —S—, —S(O)— or —S(O)O—. Rings may be substituted multiple times.
The terms “electron-withdrawing” or “electron-donating” refer to the ability of a substituent to withdraw or donate electrons relative to that of hydrogen if hydrogen occupied the same position in the molecule. These terms are well-understood by one skilled in the art and are discussed in Advanced Organic Chemistry by J. March, 1985, pp. 16-18, incorporated herein by reference. Electron withdrawing groups include halo, nitro, carboxyl, lower alkenyl, lower alkynyl, carboxaldehyde, carboxyamido, aryl, quaternary ammonium, trifluoromethyl, and aryl lower alkanoyl among others. Electron donating groups include such groups as hydroxy, lower alkyl, amino, lower alkylamino, di(lower alkyl)amino, aryloxy, mercapto, lower alkylthio, lower alkylmercapto, and disulfide among others. One skilled in the art will appreciate that the aforesaid substituents may have electron donating or electron withdrawing properties under different chemical conditions. Moreover, the present invention contemplates any combination of substituents selected from the above-identified groups.
The most preferred electron donating or electron withdrawing substituents are halo, nitro, alkanoyl, carboxaldehyde, arylalkanoyl, aryloxy, carboxyl, carboxamide, cyano, sulfonyl, sulfoxide, heterocyclyl, guanidine, quaternary ammonium, lower alkenyl, lower alkynyl, sulfonium salts, hydroxy, lower alkoxy, lower alkyl, amino, lower alkylamino, di(lower alkyl)amino, amine lower alkyl mercapto, mercaptoalkyl, alkylthio and alkyldithio.
Asymmetric centers may exist in the compounds of the present invention. Except where otherwise noted, the present invention contemplates the various stereoisomers and mixtures thereof.
As used herein, the term “composition” is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from a combination of the specified ingredients in the specified amounts.
The term “aprotic solvent” as used herein refers to a solvent that is relatively inert to proton activity (not acting as a proton donor). Examples include, but are not limited to, hydrocarbons such as hexane and toluene; halogenated hydrocarbons such as methylene chloride, ethylene chloride and chloroform among others; heterocyclic compounds such as tetrahydrofuran and N-methylpyrrolidinone and ethers such as diethyl ether and bis-methoxymethylether. It will be understood by those skilled in the art that individual solvents or mixtures thereof may be preferred for specific compounds and reaction conditions, depending upon such factors as solubility of reagents, reactivity of reagents and preferred temperature ranges for example. Further discussions of aprotic solvents may be found in Organic Solvents, Physical Properties and Methods of Purification, 4th ed., John A. Riddick el al. eds., Vol II in the Techniques of Chemistry Series, 1986, among others.
“Hydroxy protecting group” as used herein, refers to an easily removable group known in the art to protect a hydroxyl group against undesirable reaction during synthetic procedures, which can then be selectively removed. The use of hydroxy protecting groups is well known in the art, and is described in detail in Protective Groups in Organic Synthesis , by T. Greene and P. Wuts., published by John Wiley & Sons in New York in 1991. Examples of hydroxy protecting groups include, but are not limited to, methylthiomethyl, tert-dimethylsilyl and tert-butyldiphenylsilyl among others.
The term “mammals” includes humans and other animals.
The term “heteroatom” as used herein encompasses nitrogen, sulfur and oxygen.
Abbreviations
Abbreviations which have been used in the examples which follow are: HEPES for N-2-hydroxyethylpiperazine-N′-2-ethane sulfonic acid; EDTA for ethylene diaminotetraacetic acid; DTT for dithiothreitol; iNOS for inducible nitric oxide synthase; GAPDH for glyceraldehyde 3-phosphate dehydrogenase; NBT for nitro blue tetrazolium; BCIP for 5-bromo-4-chloro-3-indolyl phosphate; PPV for papaverine; L-NNA for N-nitro-L-arginine; LPS for lipopolysaccharide; TNS for transmural nerve stimulation; TTX for tetrodotoxin; TEA for tetraethylammonium; MTT for 3-(4,5-dimethyl-thizol-2-yl)-2,5-diphenyl tetrazolium bromide; DMSO for dimethyl sulfoxide and COX-2 for cyclooxygenase-2. Flavone is 2-phenylchromone; use of the term flavone and flavones herein encompasses 2-phenylchromone derivatives such as narigenin, 5,6-dimethoxy-7-benzyloxy-flavone, wogonin, 5,7-dihydroxy-6-methoxyflavone (oroxylin A), and 5,6,7-trihydroxyflavone. Use of the term flavone herein also encompasses iso-flavones.
Amino acids are abbreviated as follows: C for L-cysteine; D for L-aspartic acid; E for L-glutamic acid; G for glycine; H for L-histidine; I for L-isoleucine; L for L-leucine; N for L-asparagine; P for L-proline; Q for L-glutamine; S for L-serine; A for L-adenine; T for L-threonine; V for L-valine, and W for L-tryptophan.
Diseases which may be treated by compounds which inhibit either iNOS or COX-2 or both include the following: heart disease, asthma, arthritis, stroke, migraine disease, colon cancer, Alzheimer's disease, aneurysms, stopping uterine contractions (tocolytic effect), sepsis syndrome and cancer. Organ transplantation may also be facilitated by such inhibitors.
The compounds useful for the practice of the method, as well as in the compositions described above, may be obtained either by synthesis, or by extraction from plants, which are both well known to those skilled in the art.
The plants that active ingredients can be extracted from are known for use in traditional Chinese herbal remedies. For example, in U.S. Pat. No. 5,447,719, Scutellaria root was extracted to obtain an oroxylin derivative, which was useful as a beta-glucuronidase inhibitor. Isolation techniques are also disclosed in “Oroxylin”, J. Chem. Soc., 79, 954, 1901;. and “The Constitution of Oroxylin-A, a Yellow Colouring Matter from the Root-bark of Oroxylin Indicum”, J. Chem. Soc., 1936, 591.
Synthetic procedures to make flavones are disclosed in “Ring Isomerization of Flavones, New Synthesis of Oroxylin-A and 7-Methyl-Oroxylin-A”, Tet. Let., 48, 1985, pp. 4281-4282; and “Nuclear Oxidation in Flavones and Related Compounds”, Proc. Indian Acad. Sci., 29A. 1949.
As to therapeutic uses for flavones, flavone acetic acid was cited as an inhibitor of cyclooxygenase in U.S. Pat. No. 5,071,872; and as a nitric oxide scavenger in U.S. Pat. No. 5,612,310. Some flavone derivatives have been described as having anti-inflammatory properties in U.S. Pat. Nos. 5,013,852; 5,889,003 and 5,849,733.
The compounds of the present invention can be used in the form of pharmaceutically acceptable salts derived from inorganic or organic acids. The phrase “pharmaceutically acceptable salt” means those salts which are, within the scope of sound medical judgement, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well-known in the art. For example, S. M. Berge et al. describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 1977, 66: p. 1 et seq. The salts can be prepared in situ during the final isolation and purification of the compounds of the invention or separately by reacting a free base function with a suitable organic acid. Representative acid addition salts include, but are not limited to acetate, adipate, alginate, citrate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, camphorate, camphorsulfonate, digluconate, glycerophosphate, hemisulfate, heptanoate, hexanoate, fumarate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethansulfonate(isothionate), lactate, maleate, methanesulfonate, nicotinate, 2-naphthalenesulfonate, oxalate, palmitoate, pectinate, persulfate, 3-phenylpropionate, picrate, pivalate, propionate, succinate, tartrate, thiocyanate, phosphate, glutamate, bicarbonate, p-toluenesulfonate and undecanoate. Also, the basic nitrogen-containing groups can be quaternized with such agents as lower alkyl halides such as methyl, ethyl, propyl, and butyl chlorides, bromides and iodides; dialkyl sulfates like dimethyl, diethyl, dibutyl and diamyl sulfates; long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides; arylalkyl halides like benzyl and phenethyl bromides and others. Water or oil-soluble or dispersible products are thereby obtained. Examples of acids which can be employed to form pharmaceutically acceptable acid addition salts include such inorganic acids as hydrochloric acid, hydrobromic acid, sulphuric acid and phosphoric acid and such organic acids as oxalic acid, maleic acid, succinic acid and citric acid.
Basic addition salts can be prepared in situ during the final isolation and purification of compounds of this invention by reacting a carboxylic acid-containing moiety with a suitable base such as the hydroxide, carbonate or bicarbonate of a pharmaceutically acceptable metal cation or with ammonia or an organic primary, secondary or tertiary amine. Pharmaceutically acceptable salts include, but are not limited to, cations based on alkali metals or alkaline earth metals such as lithium, sodium, potassium, calcium, magnesium and aluminum salts and the like and nontoxic quaternary ammonia and amine cations including ammonium, tetramethylammonium, tetraethylammonium, methylamine, dimethylamine, trimethylamine, triethylamine, diethylamine, ethylamine and the like. Other representative organic amines useful for the formation of base addition salts include ethylenediamine, ethanolamine, diethanolamine, piperidine, piperazine and the like. Preferred salts of the compounds of the invention include phosphate, tris and acetate.
Dosage forms for topical administration of the flavones include powders, sprays, ointments and inhalants. The active compound is mixed under sterile conditions with a pharmaceutically acceptable carrier and any needed preservatives, buffers or propellants which can be required. Opthalmic formulations, eye ointments, powders and solutions are also contemplated as being within the scope of this invention.
Actual dosage levels of active ingredients in the pharmaceutical compositions used in the method of this invention can be varied so as to obtain an amount of the active compound(s) which is effective to achieve the desired therapeutic response for a particular patient, compositions and mode of administration. The selected dosage level will depend upon the activity of the particular compound, the route of administration, the severity of the condition being treated and the condition and prior medical history of the patient being treated. However, it is within the skill of the art to start doses of the compound at levels lower than required to achieve the desired therapeutic effect and to gradually increase the dosage until the desired effect is achieved.
When used in the above or other treatments, a therapeutically effective amount of one of the compounds used in the method of the present invention can be employed in pure form or, where such forms exist, in pharmaceutically acceptable salt, ester or prodrug form. Alternatively, the compound can be administered as a pharmaceutical composition containing the compound of interest in combination with one or more pharmaceutically acceptable excipients. The phrase “therapeutically effective amount” of the compound of the invention means a sufficient amount of the compound to treat disorders, at a reasonable benefit/risk ratio applicable to any medical treatment. It will be understood, however, that the total daily usage of the compounds and compositions of the present invention will be decided by the attending physician within the scope of sound medical judgement. The specific therapeutically effective dose level for any particular patient will depend upon a variety of factors including the disorder being treated and the severity of the disorder; activity of the specific compound employed; the specific composition employed; the age, body weight, general health, sex and diet of the patient; the time of administration, route of administration, and rate of excretion of the specific compound employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound employed; and like factors well known in the medical arts. For example, it is well within the skill of the art to start doses of the compound at levels lower than required to achieve the desired therapeutic effect and to gradually increase the dosage until the desired effect is achieved.
The total daily dose of the compounds used in the method of this invention administered to a human or lower animal may range from about 0.0001 to about 1000 mg/kg/day. For purposes of oral administration, more preferable doses can be in the range of from about 0.001 to about 5 mg/kg/day. If desired, the effective daily dose can be divided into multiple doses for purposes of administration; consequently, single dose compositions may contain such amounts or submultiples thereof to make up the daily dose.
The compounds of the present invention may be co-treated with an antibiotic. As used herein, the term “antibiotic” refers to a chemical substance which possesses activity against a specific microorganism. Examples of suitable antibiotics include penicillin, cephalosporin, vancomycin, polymyxin B, aminoglycosides, tetracyclines, chloramphenicol, erythromycin, clindamycin, rifampin, metronidazole, quinolones and sulfonamides among others.
For the practice of the method, the compounds of the present invention may be formulated together with one or more non-toxic pharmaceutically acceptable carriers. The pharmaceutical compositions can be specially formulated for oral administration in solid or liquid form, for parenteral injection or for rectal administration.
The pharmaceutical compositions used in the method of this invention can be administered to humans and other mammals orally, rectally, parenterally, intracisternally, intravaginally, intraperitoneally, topically (as by powders, ointments or drops), bucally or as an oral or nasal spray. The term “parenterally,” as used herein, refers to modes of administration which include intravenous, intramuscular, intraperitoneal, intrasternal, subcutaneous and intraarticular injection and infusion.
Moreover, pharmaceutical compositions used in the method of the present invention may include a physiologically tolerable diluent. The method of the present invention includes one or more compounds as described above formulated into compositions together with one or more non-toxic physiologically tolerable or acceptable diluents, carriers, adjuvants or vehicles that are collectively referred to herein as diluents, for parenteral injection, for intranasal delivery, for oral administration in solid or liquid form, for rectal or topical administration, or the like.
The compositions used in the method can also be delivered through a catheter for local delivery at a target site, via an intracoronary stent (a tubular device composed of a fine wire mesh), or via a biodegradable polymer. The compounds may also be complexed to ligands, such as antibodies, for targeted delivery.
Compositions suitable for parenteral injection may comprise physiologically acceptable, sterile aqueous or nonaqueous solutions, dispersions, suspensions or emulsions and sterile powders for reconstitution into sterile injectable solutions or dispersions. Examples of suitable aqueous and nonaqueous carriers, diluents, solvents or vehicles include water, ethanol, polyols (propylene glycol, polyethylene glycol, glycerol, and the like), vegetable oils (such as olive oil), injectable organic esters such as ethyl oleate, and suitable mixtures thereof.
These compositions can also contain adjuvants such as preserving, wetting, emulsifying, and dispensing agents. Prevention of the action of microorganisms can be ensured by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, and the like. It may also be desirable to include isotonic agents, for example sugars, sodium chloride and the like. Prolonged absorption of the injectable pharmaceutical form can be brought about by the use of agents delaying absorption, for example, aluminum monostearate and gelatin.
Suspensions, in addition to the active compounds, may contain suspending agents, as for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, or mixtures of these substances, and the like.
Proper fluidity can be maintained, for example, by the use of coating materials such as lecithin, by the maintenance of the required particle size in the case of dispersions and by the use of surfactants.
In some cases, in order to prolong the effect of the drug, it is desirable to slow the absorption of the drug from subcutaneous or intramuscular injection. This can be accomplished by the use of a liquid suspension of crystalline or amorphous material with poor water solubility. The rate of absorption of the drug then depends upon its rate of dissolution which, in turn, may depend upon crystal size and crystalline form. Alternatively, delayed absorption of a parenterally administered drug form is accomplished by dissolving or suspending the drug in an oil vehicle.
Injectable depot forms are made by forming microencapsule matrices of the drug in biodegradable polymers such as polylactide-polyglycolide. Depending upon the ratio of drug to polymer and the nature of the particular polymer employed, the rate of drug release can be controlled. Examples of other biodegradable polymers include poly(orthoesters) and poly(anhydrides). Depot injectable formulations are also prepared by entrapping the drug in liposomes or microemulsions which are compatible with body tissues.
The injectable formulations can be sterilized, for example, by filtration through a bacterial-retaining filter or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved or dispersed in sterile water or other sterile injectable medium just prior to use.
Solid dosage forms for oral administration include capsules, tablets, pills, powders and granules. In such solid dosage forms, the active compound may be mixed with at least one inert, pharmaceutically acceptable excipient or carrier, such as sodium citrate or dicalcium phosphate and/or a) fillers or extenders such as starches, lactose, sucrose, glucose, mannitol and silicic acid; b) binders such as carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidone, sucrose and acacia; c) humectants such as glycerol; d) disintegrating agents such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates and sodium carbonate; e) solution retarding agents such as paraffin; f) absorption accelerators such as quaternary ammonium compounds; g) wetting agents such as cetyl alcohol and glycerol monostearate; h) absorbents such as kaolin and bentonite clay and i) lubricants such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate and mixtures thereof. In the case of capsules, tablets and pills, the dosage form may also comprise buffering agents.
Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like.
The solid dosage forms of tablets, dragees, capsules, pills and granules can be prepared with coatings and shells such as enteric coatings and other coatings well-known in the pharmaceutical formulating art. They may optionally contain opacifying agents and may also be of a composition such that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions which can be used include polymeric substances and waxes.
The active compounds can also be in micro-encapsulated form, if appropriate, with one or more of the above-mentioned excipients.
Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups and elixirs. In addition to the active compounds, the liquid dosage forms may contain inert diluents commonly used in the art such as, for example, water or other solvents, solubilizing agents and emulsifiers such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, dimethyl formamide, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor and sesame oils), glycerol, tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan and mixtures thereof.
Besides inert diluents, the oral compositions may also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring and perfuming agents.
Compositions for rectal or vaginal administration are preferably suppositories which can be prepared by mixing the compounds of this invention with suitable non-irritating excipients or carriers such as cocoa butter, polyethylene glycol or a suppository wax which are solid at room temperature but liquid at body temperature and therefore melt in the rectum or vaginal cavity and release the active compound.
Compounds used in the method of the present invention can also be administered in the form of liposomes. As is known in the art, liposomes are generally derived from phospholipids or other lipid substances. Liposomes are formed by mono- or multi-lamellar hydrated liquid crystals which are dispersed in an aqueous medium. Any non-toxic, physiologically acceptable and metabolizable lipid capable of forming liposomes can be used. The present compositions in liposome form can contain, in addition to a compound of the present invention, stabilizers, preservatives, excipients and the like. The preferred lipids are natural and synthetic phospholipids and phosphatidyl cholines (lecithins) used separately or together.
Methods to form liposomes are known in the art. See, for example, Prescott, Ed., Methods in Cell Biology , Volume XIV, Academic Press, New York, N.Y. (1976), p. 33 el seq.
The term “pharmaceutically acceptable prodrugs” as used herein represents those prodrugs of the compounds of the present invention which are, within the scope of sound medical judgement, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response, and the like, commensurate with a reasonable benefit/risk ratio, and effective for their intended use, as well as the zwitterionic forms, where possible, of the compounds of the invention. Prodrugs of the present invention may be rapidly transformed in vivo to the parent compound of the above formula, for example, by hydrolysis in blood. A thorough discussion is provided in T. Higuchi and V. Stella, Pro - drugs as Novel Delivery Systems , V. 14 of the A.C.S. Symposium Series, and in Edward B. Roche, ed., Bioreversible Carriers in Drug Design , American Pharmaceutical Association and Pergamon Press (1987), hereby incorporated by reference.
The present invention contemplates both flavones of the present invention, as well as flavones formed by in vivo conversion to compounds of the present invention.
Compounds used in the method of the present invention may exist as stereoisomers wherein asymmetric or chiral centers are present. These stereoisomers are “R” or “S” depending on the configuration of substituents around the chiral carbon atom. The present invention contemplates various stereoisomers and mixtures thereof. Stereoisomers include enantiomers and diastereomers, and mixtures of enantiomers or diastereomers. Individual stereoisomers of compounds of the present invention may be prepared synthetically from commercially available starting materials which contain asymmetric or chiral centers or by preparation of racemic mixtures followed by resolution well-known to those of ordinary skill in the art. These methods of resolution are exemplified by (1) attachment of a mixture of enantiomers to a chiral auxiliary, separation of the resulting mixture of diastereomers by recrystallization or chromatography and liberation of the optically pure product from the auxiliary or (2) direct separation of the mixture of optical enantiomers on chiral chromatographic columns.
The compounds used in the method of the invention can exist in unsolvated as well as solvated forms, including hydrated forms, such as hemi-hydrates. In general, the solvated forms, with pharmaceutically acceptable solvents such as water and ethanol among others are equivalent to the unsolvated forms for the purposes of the invention.
The ability of the method of the present invention to prevent inflammation is described in detail hereinafter in the Examples. These Examples are presented to describe preferred embodiments and utilities of the invention and are not meant to limit the invention unless otherwise stated in the claims appended hereto.
The following general information may be applied to all of the Examples.
Cells. RAW264.7, a mouse macrophage cell line, was obtained from American Type Culture Collection. Cells were cultured in RPMI-1640 medium (available from Gibco Life Technology, in Gaithersburg, Md.) supplemented with 2 mM L-glutamine, antibiotics (100 units/ml penicillin-A and 100 units/ml streptomycin) and 10% heat-inactivated fetal bovine serum (Gibco/BRL) and maintained at 37° C in a humidified incubator containing 5% CO 2 .
Agents. Eight different polyphenolic compounds were isolated from Taiwanese and Chinese herbal plants for testing. They were classified into three types:
(1) Flavonoids: myricitrin (N1) was isolated from the leaves of Cupea hyssopifolia (Lythraceae) and oroxylin (N2) from the root of Scutellaria baicalensis (Labiatae);
(2) Ellagitannin: Penta-O-galloyl-β-glucopyranose (N3), Woodfordin C (N4), oenothein B (N5) and cuphiin D1 (N6), were isolated from the leaves of C. hyssopifolia (Lythraceae); and
(3) Anthraquinones: Emodin (N7) and physcion (N8) were isolated from Rheum palmatum (Polygonaceae).
Nitrite assay. The nitrite concentration in the medium was measured as an indicator of NO production according to the Griess reaction (Kim et al., J. Immunol. 153: 4741-4748). One hundred microliters of each supernatant was. mixed with the same volume of Griess reagent (1% sulfanilamide in 5% phosphoric acid and 0. 1% naphthylethylenediamine dihydrochloride in water); absorbency of the mixture at 550 nm was determined with an enzyme-linked immunosorbent assay plate reader (Dynatech MR-7000; Dynatech Labs, Chantilly, Va.).
Western blots. Total cellular extract, cytosolic fractions (for IkB) and nuclear fraction (for p65 antibody) were prepared according to Muller et al., Immunobiology, 187, 233-256, 1993 and separated on sodium dodecyl sulfatepolyacrylamide minigels (8% for iNOS or COX-2, and 10% for IkB or p65) and transferred to immobilon polyvinylidene difluoride membranes (Millipore, Bedford, Mass.). The membrane was incubated overnight at 4° C. with 1% bovine serum albumin and then incubated with anti-iNos, COX-2, α-Tubulin monoclonal antibodies (Transduction Laboratories, Lexington, Ky.), anti-IkB or anti-p65 polyclonal antibodies (Santa Cruz Biochemicals, Santa Cruz, Calif.). iNOS, IkB, p65, Cox-2, α-Tubulin were detected by NBT and BCIP staining (Sigma Chemical Co., St. Louis, Mo.).
Northern blot analysis. Total RNA (20 μg/lane) were separated by electrophoresis on 1.2% agarose gel containing 6.7% formaldehyde and transformed to a Hybond-N nylon membrane (American Life Science) in 20×standard saline citrate (3 M sodium chloride and 0.3 M sodium citrate, pH 7.0). After heating at 80° C. for 2 hours and prehybridization for 4 hours, the filters were hybridized with 32 P-labeled murine iNOS cDNA probes at a concentration of 3×10 6 cpm/ml for 16-18 hours at 42° C. The probe was labeled with [α-32P] dCTP by using Random Primer labeling kit (Stratagene, La Jolla, Calif.). Then, the filters were washed, dried and autoradiographed with Kodak-X-Omat XAR-film using intensifying screens at −80° C.
Transient transfections and luciferase activity assay. All transfectants were carried out using standard calcium phosphate precipitation procedure. For luciferase activity assays, RAW264.7 macrophages were transfected with 2 μg reporter plasmid containing 5×NF-kB sites in its enhancer element (STRATAGENE, La Jolla, Calif.). After 48-72 hours, cells were treated with LPS alone or LPS plus each indicated compound for 4 hours, then cells were lysed by lysis. buffer (0.5 M HEPES, pH. 7.4; 1 mM CaCl 2 ; mM MgCl 2 ; 1% Trixton X-100). Analysis of luciferase activity was performed using a a Luciferase reporter gene assay kit (Packard BioScience Company). Establishment of Bcl-2/RAW264.7 macrophage cells. RAW264.7 cells expressing Bcl-2 were created by electroporation (model T800; BTx, San Diego, Calif.) of RAW264.7 cells with Bcl-2 expression vector pC-Δj-bcl-2 (a gift from Dr. S. -F. Yang for Institute of Molecule Biology, Academic Scinica, Taiwan) or neo-controlled vector. pC-Δj-bcl-2, the expression vector that carries the human Bcl-2 cDNA under control of the SV40 promoter/enhancer sequence, was developed and has recently been used in our previous study, Chen, Y. C., J. Cell Physiol. 17, 324-333, 1998. Briefly, cells were suspended in 1 ml N-2-hydroxyethylipiperazine-N′-2 ethanesulfonic acid (HEPES)-buffered saline containing plasmid DNA, they received electric treatment as followed; electric amplitude, 350V; pulse width, 99 μs. Stable transfectants resistant to genisticin G418 (Gibco BRL, Eggenstein, Germany) were obtained. The levels of bcl-2 expression of each clone were examined by western blotting.
Electrophoretic mobility shift assay. Nuclear and cytoplasmic extracts were prepared according to a modified method of Chen et al., Planta Med., 55, 1-8, 1989. At the end of culture, the cells were suspended in hypotonic buffer A)10 mM HEPES, pH 7.6, 10 mM KCl, 0.1 mM EDTA, 1 mM DTT, 0.5 mM phenylmethylsulfonyl fluoride) for 10 minutes on ice and vortexed for 10 seconds. Nuclei were pelleted by centrifugation at 12000 g for 20 seconds. The supernatants containing cytosolic proteins were collected. A pellet containing nuclei was suspended in buffer C (20 mM HEPES, pH 7.6, 25% glycerol, 0.4 M NaCl, 1 mM EDTA, 1 mM DTT, 0.5 mM phenylmethylsulfonyl fluoride) for 30 minutes on ice. The supernatants containing the nuclear proteins were collected by centrifugation at 12000 g for 10 minutes and stored at −70° C. For electrophoretic mobility assay, each 10 μg of nuclear proteins was mixed with the labeled double-stranded NF-kB oligonucleotide, 5′-AGTTGA GGGGACTTTCCC AGGC-3′ (SEQ ID NO:1), and incubated at room temperature for 20 minutes (underlining indicates kB consensus sequence or binding site for NF-kB/c-Rel homodimeric and hetero dimeric complexes). The incubation mixture included 1 μg of poly(dI-dC) in a binding buffer (25 mM HEPES, pH 7.9, 0.5 mM EDTA, 0.5 mM DTT, 1% NP-40, 5% glycerol, 50 mM NaCl). The DNA/protein complex was electrophoresed on 4.5% nondenaturing polyacrylamide gels in 0.5×Tris/borate/EDTA buffer. (0.0445 M Tris, 0.0445 M. borate, 0.001 M EDTA). A double-stranded mutated oligonucleotide, 5′-AGTTGAGGCGACTTTCCCAGGC-3′ (SEQ ID NO:2) was used to examine the specificity of binding of NF-kB to DNA (the underlined sequence is identical to kB consensus sequence except for a G-to-C substitution in the NF-kB/Rel DNA binding motif). The specificity of binding was also examined by competition with the unlabeled oligonucleotide.
Chemicals. L-Arginine, lipopolysaccharide (LPS), miconazol, tetrodotoxin (TTX), papaverine (PPV), tetraethylammonium, 4-aminopyridine, N-nitro-L-arginine (L-NNA), indomethacin, eicosatriynoic acid (ETI) and glipizide were obtained from Sigma Chemical Co. (St. Louis, Mo.). Iberiotoxin was obtained from RBI (Natick, Mass.) Oroxylin A was isolated from the root of Scutellaria baicalensis (Labiatae) (Chen et al., 1999). All drugs were dissolved in deionized water as stock solutions before experiments and added as final concentrations in the Kreb's solution or the incubation medium.
General procedure. Fresh heads of adult pigs of either sex were collected from local packing companies (Excel, Beardstown, II, and Turasky's Y-T Packing, Springfield, Ill.). The entire brain, with dura matter attached, was removed and placed in Kreb's bicarbonate solution equilibrated with 95% O 2 and 5% CO 2 at room temperature. The composition of the Kreb's solution was as follows (mM): NaCl, 122.0; KCl, 5.16; CaCl 2 , 1.2; MgSO 4 , 1.22; NaHCO 3 , 25.6; ethylenediamine tetraacetic acid, 0.03; L-ascorbic acid, 0.1; and glucose, 11.0 (pH 7.4). The circle of Willis (internal carotid and posterior communicating arteries) was dissected, and surrounding tissue was cleaned off under a dissecting microscope. Some cerebral arteries were mechanically denuded of endothelium before experiments. The successful removal of endothelial cells was verified by lack of L-Arginine-induced relaxation.
In vitro tissue bath studies. The arterial segment (4 mm long) of the circle of Willis was dissected and cannulated with a stainless-steel rod (30-28 gauge) of hemispherical section, and a short piece of platinum wire, and mounted horizontally in a plastic tissue bath containing 6 ml of Krebs' bicarbonate solution. The platinum wire was bent into a U shape and anchored to a gate. The stainless-steel rod was connected to a stain gauge transducer (UC3, available from Gould) for isometric recording of changes in force. The temperature of Krebs' solution in the tissue baths, equilibrated with 95% O 2 and 5% CO 2 , was maintained at 37° C. Tissues were equilibrated in the Krebs' solution for an initial 30 minutes and were mechanically stretched to a resting tension of 0.75 g for another 30 minutes. The segments of the circle of Willis were precontracted with 9,11-dideoxy-9α,11α-epoxymethanoprostagladin F 2α (U-46619, 1 μM) to induce an active muscle tone of 0.5-0.75 g. Experimental drugs such as L-arginine and Oroxylin A of various concentrations, and TNS at 2,4,8 Hz were applied to induce relaxation. The arteries were then washed with pre-warmed Krebs' solution. A similar magnitude of active muscle tone again was induced with U-46619, and induction of relaxation by experimental drugs or TNS were repeated to compare with the relaxation before wash. For TNS, tissues were electrically, transmurally stimulated with a pair of electrodes through which 100 biphasic square-wave pulses of various frequencies were delivered. Stimulation parameters were continuously monitored on a Tektronix oscilloscope. The neurogenic origin of this TNS-induced response was verified by its complete blockade by TTX (0.3 μM) or L-NNA (30 μM). At the end of each experiment, papaverine (PPV, 300 μM) was added to induce a maximum relaxation. The magnitude of a vasodilator response induced by experimental drugs and TNS was expressed as a percentage of the maximum response induced by PPV.
Culture of smooth muscle cells. The entire brain with dura attached was removed and placed in ice-cold sterile phosphate-buffered saline (PBS) (140 mM NaCl, 4 mM KCl, 1 mM KH 2 PO 4 , pH 7.4) containing antibiotics (100 U/ml penicillin G potassium, 100 μg/ml streptomycin sulfate, and 0.25 μg/ml fungizone) (Fisher Scientific, Springfield, N.J.). The arteries of the circle of Willis were removed and cleaned of surrounding tissue under a dissecting microscope. The arteries were then placed on a sterile petri dish and sliced longitudinally. The luminal surface was rubbed with a sterile cotton swab to remove endothelial cells. The vessels were placed in DMEM (Dulbecco's Modified Eagle Medium, Life Technologies, Grand Island, N.Y.) containing antibiotics and stored overnight at 4° C. The vessels were cut into approximately 2×2-mm explants, placed in a 10 cm petri dish, covered with DMEM containing antibiotics plus 20% FBS (fetal bovine serum, Sigma Chemical Co., St Louis, Mo.), and placed in an incubator in an atmosphere of 5% CO 2 in air at 37° C. After 7-10 days, the cells were removed and the medium was changed every 2-3 days until the cells reach confluence. Cells were then passaged into 24-well culture dishes using 0.25% trypsin and were grown in DMEM plus 10% fetal bovine serum (FBS, available from Hyclone Lab of Logem, Utah) and antibiotics. Experiments were performed on cells at passages 2-10.
Incubation of cerebral arteries with LPS. Endothelium-denuded arterial segments of the circle of Willis were incubated for 20 hours (37° C.) in M199 medium containing 5% fetal bovine serum (Life Technologies, Grand Island, N.Y.) in the presence of LPS (10 μg/ml) with or without oroxylin A. Additional segments of arteries were incubated in the same medium in the absence of LPS for same length of time, and served as negative controls.
Western blots. Total cellular extract of smooth muscle cells was prepared and separated on 7.5% sodium dodecyl sulfate-polyacrylamide minigels (Hoefer Pharmacia Biotech, San Francisco, Calif.) and transferred to immobilon polyvinylidene difluoride membranes (Millipore, Bedford, Mass.). The membrane was incubated overnight at 4° C. with 1% bovine serum albumin and then incubated with anti-iNOS monoclonal antibody (Transduction Laboratories, Lexington, Ky.). Expression of iNOS was detected by NBT and BCIP staining (Sigma Chemical Co., St. Louis, Mo.).
Immunohistochemistry. For demonstrating the expression of iNOS protein induced by LPS in porcine cerebral arteries and smooth muscle cells, immunohistochemistry was carried out using an indirect immunofluorescence method. The arteries of the circle of Willis were incubated in the presence of LPS with or without oroxylin A at 37° C. for 20 hours, and followed by fixation with PPPFL fixative (periodate-picric acid-paraformaldehyde-lysine) for 24 hours. After fixation, arteries were rinsed in 0.01 M PBS (pH 7.4) 3 times and sectioned at 12 μm thickness with a Micron 505E cryostat microtome (Zeiss, N.Y, N.Y.). The sections were mounted on coated slides (Vectabond Reagent; Vector Labs) and processed for immunohistochemistry. Avidin-biotin complex indirect immunohistochemical methods (Vector Labs) were used to demonstrate iNOS immunoreactivity with fluorescein isothiocyanate (FITC) as chromogen. Briefly, the sectioned arteries were incubated in 0.5% normal goat serum with avidine D solution (Avidin/Biotin Blocking Kit; Vector Labs) to block endogenous biotin and then incubated with primary antibody against iNOS at a dilution 1:250 for 4 hours at room temperature. After three washes in 0.01 M PBS (pH 8.2), samples were incubated with biotinated affinity purified goat anti-mouse IgG (1:200 dilution) (Vectastain ABC Kit; Vector Labs) for 30-60 minutes at room temperature followed by 0.01 M PBS (pH 8.2) washes for three times, and then incubated with FITC-labeled avidin D (Fluorescein avidin D; Vector Labs) for 60 minutes at room temperature.
Photomicrographs of immunofluorescence at 20× were immediately taken with an Olympus fluorescence microscope fitted with an FITC filter. Similar immunostaining method was used for the cultured primary smooth muscle cells except that the cultured cells growing on poly-D-lysine coated glass coverslip were fixed in cold methanol for 20 minutes and rinsed three times with PBS.
Statistical analysis. Results were expressed as means±S.E.M. Statistical analysis was evaluated by student's t test for paired samples as appropriate. The P<0.05 level of probability was accepted as significant.
EXAMPLE 1
Effects of two flavonoids (myristricin isolated from Cuphea hyssopifolia and oroxylin A isolated from Scutellaria baicalensis ), four ellagitannins (penta-O-galloyl-β-glucopyranose, woodfordin C. oenothein B, cuphiin D1; all were isolated from C. hyssopifolia ) and two anthraquinones (emodin and physcion; both were extracted from Rheu palmatum) on PLS-induced NO production and expression of iNOS and COX-2 in RAW264.7 macrophages were studied, according to the procedures described above. The data indicated that oroxylin A was most potent among the compounds tested in blocking LPS-induced iNOS and COX-2 gene expression. The blocking effect of oroxylin A occurred via inhibition of binding of transcription factor NF-kB to iNOS promoter. Emodin which also showed a potent inhibitory effect, comparable to oroxylin A, on LPS-induced iNOS gene expressions. Similar findings were found in Bcl-2 overexpressed RAW264.7 cells.
The effects of flavonoids, ellagitannins, anthraquinones on LPS-induced NO production in macrophages were studied as follows. The chemical structures of two flavonoids (myricitrin, N1; oroxylin A, N2) four ellagitannins (penta-O-galloyl-β-glucopyranose, N3; woodfordin C, N4; onothein B, N5; cuphiin, N6), and two anthraquinones (emodin, N7; physcion, N8) that were used in the present study were shown in FIG. 1 . The effects of these eight compounds on NO production in RAW264.7 macrophages were investigated. The accumulated nitrite in the culture medium was used as an index for NO synthesis from these cells. Each of these eight compounds, at the concentration of 20 μg/ml, did not interfere with the reaction between nitrite and Griess reagent. Unstimulated macrophages, after 24 hours of incubation in the culture, produced background levels of nitrite (Control, FIG. 2 ). When the resting cells were incubated with each indicated compound alone, amount of nitrite in the medium was maintained at a background level similar to that in the unstimulated samples. After treatment with LPS (100 ng/ml) for 24 hours, nitrite concentration was significantly increased for about 20 fold (˜35 μM). When macrophages were incubated with various concentrations of each compound (5, 10 or 20 μg/ml) (1, 2 or 3 respectively, FIG. 2) together with 100 ng/ml LPS for 24 hours, significant inhibition of nitrite production was detected in the presence of oroxylin A (N2) and emodin (N7), in a concentration-dependent manner. The remaining compounds only at highest concentration (20 μg/ml) showed slight inhibition on LPS-induced nitrite production (FIG. 2 ). Examination of effects of these eight compounds at 20 μ/ml on RAV264.7 cell viability by MTT assay indicated that only emodin at this high concentration caused a slight cytotoxity (˜30%), while other compounds did not affect the cell viability.
EXAMPLE 2
RAW264.7 macrophages did not express detectable levels of iNOS protein (FIG. 3, C) or iNOS mRNA (FIG. 4, C) when incubated with medium alone for 24 or 7 hours, respectively. Basal level of iNOS in RAW264.7 cells was not affected when incubated with each of the indicated eight compounds alone, while 100 ng/ml LPS induced a dramatic increase in iNOS protein (FIG. 3, L) and mRNA (FIG. 4, L) in these cells. Examination of effect of each of these-eight compounds on LPS-induced iNOS protein and mRNA demonstrated that among these eight compounds, only oroxylin A (N2) and emodin (N7) inhibited LPS-induced iNOS protein in a concentration-dependent manner, while amount of α-tublin protein as an internal control remained unchanged, as shown in FIG. 3 . The effect of these compounds in inhibiting LPS-induced iNOS mRNA is demonstrated in FIG. 4 .
Since NO may directly activate expression of COX isoforms, and induction of COX gene expression has been shown to be involved in process of LPS-mediated response (Cao, C. et al., Brain Res., 697, 187-196, 1995), the effect of these eight compounds on LPS-induced COX-2 gene expression was also investigated. The results indicated that only oroxylin A inhibited LPS-induced COX-2 gene expression in both protein and mRNA levels (FIG. 5 ).
Example 3
NF-kB is a transcription factor that is activated in response to stimulation by LPS, and activation of NF-kB is an essential factor in inducing iNOS gene expression in macrophages (Kim, Y. M., Biochem. Biophys. Res. Commun. 236, 655-660, 1997). To assess the effect of these compounds (20 μg/ml) on early stage of iNOS gene expression, the activation of NF-kB in RAW264.7 macrophages was examined using the electrophoretic mobility shift assay (EMSA) (FIGS. 6 i and 6 ii ). One hour after activation with LPS, the binding of NF-kB was increased remarkably in nuclear extracts of macrophages. This inductive NF-kB binding activity was significantly inhibited by myricitrin, oroxylin A and oenothein B (FIG. 6 ). In contrast, emodin did not affect the activation of NF-kB by LPS, although it was shown to inhibit nitrite production and iNOS gene expression. The NF-kB complex formation was specifically blocked by the addition of a molar excess of specific unlabeled consensus oligomer, but was not inhibited by the mutated unlabeled oligomer. In order to further demonstrate that inhibition of NF-kB activation by oroxylin A, a Luc-reporter plasmid containing five NF-kB binding sites in the enhancer element was transiently transfected into RAW264.7 cells, and analysis of luciferase activity was performed to identify the levels of NF-kB activation. The results showed that oroxylin A efficiently decreased the LPS-induced luciferase activity by four fold (FIG. 6 iii ). These data were consistent with the results of analyzing NF-kB binding by EMSA. The heteromeric NF-kB complex is sequestered in the cytoplasm as an inactive precursor complexed with an inhibitory protein, an IkB-like protein and LPS induced NF-kB activation through increasing nuclear p65 protein associated with a decrease of cytosolic IkB protein. By western blot analysis, incubation of RAW264.7 macrophages with 100 ng/ml LPS for 30 minutes was able to increase of NF-kB (p65) in the nuclear fraction and decrease of IkB protein in the cytosol (FIG. 6 iv ). This phenomenon was significantly inhibited by 20 μg/ml myristricin (N1), oroxylin A (N2) and oenothein B (N5) (FIG. 6 iii ). Emodin (N7) and cuphiin D1 (N6) treatment did not block the increase of p65 in the nucleus or degradation of IkB induced by LPS.
EXAMPLE 4
RAW264.7 macrophages were transfected with the plant pC-Δj-bcl-2 also carrying a neomycin resistance gene. Stable Bcl-2 protein expression was assessed by western blot analysis with an anti-human Bcl-2 specific antibody. Two dependent clones termed Bcl2/RAW-1 and Bcl 1/RAW-2 showed the substantial Bcl-2 overexpression (FIG. 7 A). Both clones expressed higher levels of Bcl-2 protein and neomycin-vector transfected RAW264.7 (neo/RAW) lack any human Bcl-2 protein in cells. The endogenous iNOS protein in Bcl2RAW-1 and Bcl-2/RAW-2 cells is higher than that in neo/RAW cells, and the levels of iNOS protein is Bcl-2/RAW-2>Bcl-2/RAW-1>neo/RAW. Upon treatment with 100 ng/ml LPS, significant induction of iNOS protein and nitrite production was detected in Bcl2/RAW-1 and neo/RAW, however Bcl-2/RAW-2 cells were less sensitive to LPS treatment (FIG. 7 B). In order to examine whether oroxylin A and emodin inhibit LPS-induced iNOS and COX-2 gene expressions in Bcl-2-overexpressed RAW264.7 cells, both Bcl-2/RAW-1 and Bcl-2/RAW-2 were incubated with oroxylin A or emodin (20 μg/ml) followed by activation with LPS (100 ng/ml). Analysis of iNOS and COX-2 gene expression was then performed by northern and western blots. Oroxylin A (N2) or emodin (N7) treatment inhibited LPS-induced nitrite production and iNOS gene expressions in both Bcl-2-transfected cells (FIGS. 8 and 9 A). Upon analysis of COX-2 mRNA, oroxylin A but not emodin inhibited LPS-induced COX-2 mRNA in Bcl-2-overexpressed RAW264.7 macrophages (FIG. 9 B). These results were in accordance with the results derived from parental RAW264.7 macrophages.
EXAMPLE 5
Results from immunohistochemical studies demonstrated that iNOS-immunoreactivities, which were occasionally found in the adventitia, were never found in the medial smooth muscle layer (FIG. 10A, n=6). The iNOS-immunoreactivities, however, were significantly expressed in the medial smooth muscle layer in arteries following incubation with LPS (10 μg/ml) for 20 hours (FIG. 10B, n=6). The LPS-induced expression of iNOS in the muscle layer was not found in arteries following concomitant incubation with oroxylin A (60 μM) (FIG. 10C, n=6).
The LPS induction of iNOS and its inhibition by oroxylin A in porcine cerebral arterial smooth muscle cells was further demonstrated in the primary culture of smooth muscle cells isolated from these arteries (FIG. 11 ). The smooth muscle nature of the cultured cells was verified by the presence of over 95% of cultured cells which were immunoreactive for smooth muscle α-actin (FIG. 11 ). After incubation in the presence LPS (10 μg/ml) for 20 hours, most cultured cells were iNOS-immunoreactive (iNOS-I). The iNOS-I cells were drastically decreased when these cells were cultured concomitantly with oroxylin A (60 μM). This was further verified by the results from Western blot analysis that LPS incubation alone significantly increase iNOS proteins in the cultured smooth muscle cells (FIG. 12 ). The expression of iNOS proteins was decreased by oroxylin A in a concentration-dependent manner. Oroxylin A at the concentrations used did not affect the expression of nNOS, while the total loading proteins were not different among different experimental groups.
EXAMPLE 6
L-Arginine (10-100 μM) did not induce relaxation in fresh cerebral arterial rings without endothelial cells or induced very small relaxation in those incubated in culture medium for 20 hours (FIGS. 13 A and 13 D). However, after incubation with LPS (10 μg/ml) for 20 hours, these arterial rings without endothelial cells in the presence of U-46619 (1 μM)-induced active muscle tone significantly relaxed upon application of L-Arginine (FIGS. 13 B and 13 D). This LPS-rendered L-Arginine-induced relaxation was significantly decreased when the arteries without endothelial cells were incubated concomitantly with oroxylin A (60 μM) (FIGS. 13 C and 13 D). L-NNA (30 μM) given at the end of each experiment increased basal tone significantly greater in arterial rings incubated with LPS alone than the control arteries and arteries co-incubated with LPS and oroxylin A.
EXAMPLE 7
Consistent with the previous findings that transmural nerve stimulation (TNS) at various frequencies elicited relaxation in cerebral arterial segments with or without endothelial cells in the presence of active muscle tone induced by U-46619 (1-3 μM) (FIG. 14 ). The relaxation elicited by TNS at 2, 4, and 8 Hz, which was tetrodotoxin (TTX, 0.3 μM)-sensitive, was not inhibited but was slightly and significantly enhanced by acute administration of oroxylin A (30 μM) (FIG. 15 B). The residual relaxation was abolished by L-NNA (30 μM).
EXAMPLE 8
Arterial ring segments of the circle of Willis with intact endothelium pre-contracted with U-46619 (1 μM) relaxed upon application of oroxylin A (0.1-30 μM) in a concentration-dependent manner with the maximum relaxation achieved at 30 μM (FIG. 16A, B). The medium effective concentration (EC 50 ) was 7.9(4.6-13.8 μM) (n=4). DMSO, a dissolving medium for oroxylin A, at the concentration used (as much as 0.1% vol/vol) had no effects on basal tone. Oroxylin A-induced sustained relaxation was not different (p>0.05) from that in endothelium-denuded arteries with EC 50 =8.4(5.8-9.8) μM (n=12) (FIG. 16 A). Two consecutive oroxylin A full concentration-response curves performed in same arterial preparations with 60 minute intervals and 3 washes between two applications were not different (p>0.05, n=5, FIG. 16 B). Effects of experimental drugs on oroxylin A-induced relaxation were therefore examined by applying the experimental drugs to the tissues prior to the commencement of the second concentration-response curves. In parallel, other polyphenolic compounds such as epigallocatechin gallate, emodin, ginkgolide A and ginkgolide B at concentrations as high as 100 μM caused very small relaxation or no response (n=4 for each compound) (data not shown).
EXAMPLE 9
When basilar arterial rings precontracted with 80 mM KCl, oroxylin A did not induce sustained relaxation in cerebral arteries with or without endothelial cells (FIG. 15 B). Oroxylin A induced only small transient relaxation (FIG. 15 B). The transient relaxation induced by maximum concentration of oroxylin A (60 μM) in KCl-pre-contracted arterial rings (20.2±1.63% of PPV-induced maximum relaxation, n=5) was significantly smaller than that found in same arteries with similar active muscle tone contracted with U-46619 (95.1±4.31% of PPV-induced maximum relaxation, n=5) (FIG. 15 A).
EXAMPLE 10
TEA, (tetraethylammonium) a nonspecific K + channels blocker, concentration-dependently (1-10 mM) inhibited oroxylin A-induced relaxation in cerebral arteries without endothelial cells (FIGS. 17A and 17B and Table 1). TEA at 1 mM significantly shifted the oroxylin A concentration response curves to the right (FIG. 17 B and Table 1). TEA at 10 mM almost abolished relaxation induced by oroxylin A at concentrations lower than 30 μM. Relaxation induced by oroxylin A at 5.8 μM, however, was not significantly affected by TEA at this concentration (FIG. 17 B). 4-aminopyridine (4-AP), a second nonspecific K + channel blocker, also significantly inhibited the vasodilatory effect of oroxylin A in arteries without endothelial cells pre-contracted with U-46619 (FIG. 18 and Table 1). Iberiotoxin (IBT, 100 nM), a preferential Ca 2+ activated potassium channel blocker, slightly but significantly inhibited oroxylin A-induced relaxation (Table 1). In contrast, glipizide (GLP, 30 μM), which is an ATP-sensitive K + channel blocker, did not affect oroxylin A-induced relaxation (FIG. 18 and Table 1).
TABLE 1
Effects of potassium channel inhibitors, lipoxygenase, NOS and cyclooxygenase
inhibitors on oroxylin A-induced vasorelaxation in porcine cerebral arteries.
Percent of Maximum Control Relaxation
Oroxylin A
Oroxylin A
Oroxylin A
Treatments
(3 μM)
(10 μM)
(30 μM)
EC 50 (μM)
PPV Control
24.6 ± 1.9
49.0 ± 3.4
86.0 ± 2.6
8.4(5.8-9.8)
(300 μM)
TEA (1 mM)
7.1 ± 3.0*
31.5 ± 6.6
58.6 ± 6.7*
21.5(7.4-51.3)*
TEA (10 mM)
0**
4.87 ± 1.5**
16.3 ± 2.0**
39.3(35.5-
40.7)**
4-AP (10 mM)
1.8 ± 1.6**
9.7 ± 2.0**
28.4 ± 6.7**
—
IBT (100 nM)
16.8 ± 3.1
30.8 ± 5.2**
68.1 ± 7.2**
15.0(11.2-
19.5)*
ETI (10 μM)
21.4 ± 2.1
41.3 ± 4.4
91.4 ± 1.5
8.1(3.8-13.8)
GLP (30 μM)
24.6 ± 3.4
46.5 ± 7.1
84.2 ± 7.1
11.2(8.5-14.1)
MCN (5 μM)
21.2 ± 3.4
37.4 ± 4.5
87.2 ± 2.6
10.5(7.4-14.1)
INDO (30 μM)
23.0 ± 1.8
41.8 ± 5.6
89.1 ± 3.6
10.0(6.8-13.8)
L-NNA (60 μM)
26.9 ± 3.4
45.3 ± 6.0
91.9 ± 2.8
11.4(8.5-14.8)
Tetraethylammonium (TEA), glipizide (GLP), 4-aminopyridine (4-AP), miconazole (MCN), indomethacin (INDO), N-nitro-L-arginine (L-NNA) or iberiotoxin (IBT) was administered for 20 minutes before application of oroxylin A. Relaxation-induced by oroxylin A was estimated as a percentage of maximum relaxation induced by papaverine (PPV, 300 μM).
Values are means ± S.E.M.;
Control, n = 12;
Each experimental drug, n = 5;
*P < 0.05 and **P < 0.01, indicate significant differences from the control.
“—” = not measured.
EXAMPLE 11
The possibility that vasodilation induced by oroxylin A may be mediated by metabolites of the arachidonic acid cascade was examined. Oroxylin A-induced relaxation in cerebral arteries without endothelial cells was not affected by eicosatriyonic acid (ETI, an inhibitor of 5-, 12- and 15-lipoxygenase activity; 10 μM, n=5), miconazole (MCN, a competitive inhibitor of cytochrome P-450 epoxygenase; 5 μM, n=5) or indomethacin (INDO, an inhibitor of cyclooxygenase activity; 30 μM, n=5). Oroxylin A-induced relaxation was not affected by L-NNA (60-240 μM, n=5) either (FIG. 18 and Table 1). These results indicated that lipoxygenase metabolites and NO pathway were not involved in the vasodilator response induced by oroxylin A.
EXAMPLE 12
In the present study, three oroxylin A structurally related polyphenols isolated from Chinese herbs Huang Qui including baicalin, baicalein and wogonin (FIG. 19) were examined for their effects on LPS-induced nitric oxide (NO) production, iNOS and COX-2 gene expressions in RAW 264.7 macrophages. These .polyphenolic compounds are flavonoids. The effects of baicalin, baicalein and wogonin on LPS-induced NO production in RAW 264.7 macrophages were investigated by measuring the accumulated nitrite, estimated by the Griess reaction, in the culture medium. Unstimulated macrophages, after 24 hours of incubation in the culture medium, produced background levels of nitrite. When the cells were incubated with each of the three compounds alone, the concentration of nitrite in the medium was maintained at a background level similar to that in the unstimulated samples. After treatment with LPS (100 ng/mL) for 24 hours, nitrite concentrations in the medium increased remarkably by about 20 fold (˜30 μM). When RAW 264.7 macrophages were treated with different concentrations of each of the three compounds together with LPS (100 μg/mL) for 24 hours, significant concentration-dependent inhibition of nitrite production was detected in the presence of baicalin, baicalein and wogonin. The IC 50 values of baicalin, baicalein and wogonin in inhibiting LPS-induced NO production were 15±1.4, 19.4±1.0 and 9.5±0.8 μM (n=3), respectively. Accordingly, the rank of potencies in inhibiting LPS-induced NO production was wogonin>baicalin>baicalein (p<0.01, n=3). Examination of cytotoxicity of baicalin, baicalein and wogonin in RAW 264.7 macrophages by MTT assay indicated that all three compounds, even at 40 μM, did not affect viability of RAW 264.7 cells. Therefore, inhibition of LPS-induced nitrite production by baicalin, baicalein and wogonin was not due to possible cytotoxic effect on these cells. The results indicated that these three polyphenolic compounds like oroxylin A inhibited LPS-induced NO production in a concentration-dependent manner without notable cytotoxic effect on these cells.
Decrease in NO production was in parallel with the inhibition by these polyphenolic compounds of LPS-induced iNOS gene expression. RAW 264.7 cells did not express detectable iNOS protein when incubated in the medium without LPS for 24 hours, and the basal level of iNOS protein was not affected when incubated with baicalin, baicalein or wogonin alone. Upon LPS (100 ng/mL) treatment for 24 hours, iNOS protein drastically increased in these cells, and co-treatment of cells with LPS (100 ng/mL) and different concentrations (20, 40 μM) of each of the three compounds for 24 hours significantly inhibited iNOS protein induction in RAW 264.7 macrophages. The amount of α-tubulin protein as an internal control remained unchanged.
Un-stimulated RAW 264.7 macrophages in culture medium for 24 hours produced basal amount of PGE 2 (1.5 ng/mL) in the medium. After treatment with LPS (100 ng/mL) for 24 hours, the medium concentration of PGE2 elevated significantly to 7 ng/mL. This increase was inhibited by co-treatment of cells with different concentrations of wogonin (20 and 40 μM). However, LPS-induced PGE2 production was not inhibited by baicalin or baicalein except at 40 μM, the highest concentration examined. Western blot analysis demonstrated that unstimulated RAW 264.7 macrophages expressed only a small amount of COX-2 proteins. Baicalin, baicalein, and wogonin treatment alone did not affect the basal COX-2 expression. Upon LPS (100 ng/mL) treatment for 24 hours, COX-2 protein drastically increased in these cells. The increase was significantly inhibited by co-treatment of cells with different concentrations (20, 40 μM) of wogonin for 24 hours. Baicalin and baicalein at similar concentrations did not inhibit LPS-induced COX-2 protein synthesis.
Wogonin, baicalein and baicalin, however, did not directly affect iNOS or COX-2 enzyme activity. Table 2 indicates that the addition of different concentrations (20 or 40 μM) of baicalin, baicalein, and wogonin to RAW 264.7 macrophages, which had been pre-treated with LPS to induce iNOS, did not affect iNOS enzyme activity in intact cells by measuring the amount of nitrite production in the medium. In parallel experiments, NOS inhibitors N-nitro-L-arginine (NLA) and N-nitro-L-arginine methyl ester (L-NAME) significantly decreased the nitrite production in the medium, but did not alter the iNOS enzyme activity in the cell lysates by direct NOS enzyme activity assays in vitro. Lack of direct enzyme inhibition by baicalin, baiclein and wogonin was further supported by findings that different concentrations (20, 40 μM) of baicalin, baicalein, and wogonin did not inhibit LPS-induced NO production, while it was significantly inhibited by both NLA and L-NAME treatment (Table 3).
When different concentrations (20 or 40 μM) of baicalin, baicalein and wogonin were added to RAW 264.7 macrophages in which COX-2 proteins had already been induced by LPS, there was no decrease in PGE 2 production using added arachidonic acid as a substrate (Table 4). Both NLA and L-NAME did not affect PGE 2 production, which however was significantly inhibited by indomethacin, a cyclooxygenase enzyme inhibitor.
It has been suggested that NO is a key factor in terminating the inflammation through an autoregulatory feedback inhibition of iNOS synthesis in LPS or cytokines treated cells. Accordingly, NOS enzyme inhibitors such as NLA and L-NAME significantly inhibit NO production, while these inhibitors stimulate iNOS gene expression. In the present study, NLA and L-NAME significantly inhibited LPS-induced NO (but not PGE 2 ) production (Table 5). NLA and L-NAME enhanced LPS (100 ng/mL)-induced iNOS (but not COX-2) gene expression by about 3-fold (**P<0.01, compared with LPS-treated group) by western blot analysis. The increased expression of iNOS was inhibited by baicalin, baicalein or wogonin in a concentration-dependent manner. Wogonin but not baicalin or baicalein inhibited expression of COX-2 proteins in NLA (or L-NAME) plus LPS co-treated RAW 264.7 macrophages. These results indicated that co-treatment with NOS inhibitors and polyphenolic compounds such as wogonin effectively blocked acute production of NO and, at the same time, inhibited expressions of iNOS and COX-2 genes. Wogonin like oroxylin A in combination with NOS inhibitors appears to be useful in the prevention and treatment of diseases due to increased expression of iNOS and COX-2 such as in endotoxemia.
TABLE 2
Effects of baicalin, baicalein and wongonin on LPS-induced NO
synthesis and iNOS enzyme activity in RAW 264.7 macrophages.
Addition to
LPS-treated
NO in medium
iNOS specific activity:
LPS pretreatment
RAW 264.7
(μM/6 × 10 5
NO formation
of cells
cells
cells)
(μM/200 μg protein)
None
DMSO
0.0 ± 0.0
1.5 ± 0.8
control
LPS (100 ng/ml),
Control
16.9 ± 0.5
8.9 ± 1.2
12 hours
Baicalein
20 μM
15.4 ± 0.3
9.8 ± 2.3
40 μM
13.1 ± 0.9
8.1 ± 1.9
Baicalin
20 μM
14.5 ± 0.5
8.7 ± 1.3
40 μM
14.8 ± 1.5
9.4 ± 2.1
Wogonin
20 μM
16.5 ± 0.3
8.7 ± 3.1
40 μM
16.3 ± 0.3
8.9 ± 2.7
NLA
2 mM
0.3 ± 0.1**
9.4 ± 2.1
L-NAME
2 mM
0.4 ± 0.2**
9.7 ± 1.5
RAW264.7 macrophages were stimulated with LPS (100 ng/mL) for 12 hours and cells were washed twice with PBS to remove LPS. RAW cells were then scraped and placed in a 24-well plate and the indicated compounds were added and incubated at 37° C. incubator for additional 12 hours. The amount of NO accumulated in the medium and alternation of iNOS enzyme activity in cell lysates were detected
# by indirect and direct NOS enzyme assays as described above. Data are mean ± SEM from three independent experiments.
**P < 0.01 indicates significantly different from LPS alone (unpaired t test).
TABLE 3
Effects of baicalin, baicalein, and wogonin on iNOS activity
by direct enzyme activity assay in RAW 264.7 cell lysates.
iNOS specific activity:
Pretreatment of cells
NO formation
before lysis
Addition to lysate
(μM/200 μg total protein) a
None
DMSO
1.1 ± 0.5
LPS (100 ng/mL),
DMSO
8.6 ± 0.4
12 hr
Baicalin
20 μM
8.7 ± 1.0
40 μM
9.0 ± 1.1
Baicalein
20 μM
7.2 ± 0.1
40 μM
9.2 ± 1.8
Wogonin
20 μM
8.1 ± 0.2
40 μM
7.5 ± 0.1
NLA
4 mM
4.2 ± 0.4**
L-NAME
4 mM
3.9 ± 0.6**
a The values were obtained from three separate experiments and described as means ± SEM. Lysate preparation and iNOS activity assay were described above. Each indicated compound was added into lysates (200 μg) from LPS-treated RAW264.7 macrophages and iNOS activity was measured.
**P < 0.01 indicates significantly different from LPS alone (unpaired t test)
TABLE 4
Effects of added baicalein, baicalin, wogonin, indomethacin,
NLA and L-NAME on LPS-induced COX-2 enzyme
in RAW 264.7 cells
Addition to LPS-treated
LPS treatment of Cells a
RAW 264.7 cells
PGE2 (ng/mL) b
None
DMSO
0.2 ± 0.0
LPS
DMSO
6.5 ± 0.2
Baicalin
20 μM
6.1 ± 0.6
40 μM
5.9 ± 0.4
Baicalein
20 μM
6.1 ± 0.2
40 μM
6.2 ± 0.5
Wogonin
20 μM
5.9 ± 0.7
40 μM
5.7 ± 0.4
Indomethacin
20 μM
2.0 ± 0.7**
NLA
2 mM
5.6± 0.9
L-NAME
2 mM
6.2 ± 0.6
a RAW264.7 cells were stimulated with LPS (100 ng/mL) for 6 hours,and cells were washed twice with fresh medium. Baicalin, baicalein or other indicated compounds was then added and incubated at 37° C. for 30 min. The cells were further incubated with arachidonic acid (100 μM) for 15 min.
b The amount of PGE2 in the supernatant was assayed as described above. Data are means ± SEM of three samples from two independent experiments. In each experiment, duplicate determinations were made for each experiment.
**P < 0.01 indicates significantly different from LPS alone (unpaired t test)
TABLE 5
Effects of baicalin, baicalein; wogonin on NLA or L-NAME stimulated
LPS-induced NO and PGE2 productions in RAW 264.7 macrophages a .
Treatment of cells
NO (μmole/4 × 10 5 )
PGE2 (ng/mL)
Control
3.7 ± 0.7
1.8 ± 0.4
LPS
30.0 ± 0.6
7.1 ± 0.8
NLA (2 mM))
3.7 ± 0.3
1.5 ± 0.5
LPS + NLA (2 mM)
9.7 ± 0.2**
7.2 ± 0.6
LPS + NLA (2 mM) + Baicalin
7.1 ± 0.3**
5.8 ± 1.1
(40 μM)
LPS + NLA (2 mM) + Baicalein
8.3 ± 1.3**
5.5 ± 0.8*
(40 μM)
LPS + NLA (2 mM) + Wogonin
6.7 ± 0.7**
2.1 ± 0.4**
(40 μM) L-NAME (2 mM)
5.1 ± 0.4
1.3 ± 0.6
LPS + L-NAME (2 mM)
7.3 ± 1.2**
6.9 ± 0.9
LPS + L-NAME (2 mM) +
8.5 ± 0.9**
6.1 ± 0.3
Baicalin (40 μM)
LPS + L-NAME (2 mM) +
7.9 ± 1.2**
6.2 ± 0.5
Baicalein (40 μM)
LPS + L-NAME (2 mM) +
6.8 ± 0.5**
2.3 ± 0.7**
Wogonin (40 μM)
a RAW 264.7 cells were co-treated with LPS (100 ng/mL) and indicated compounds for 24 hours.
The amount of NO and PGE2 accumulated in the supernatant was detected by Griess assay and PGE2 assay kit as described above.
Data are means ± SE from three independent experiments.
*P < 0.05 and **P < 0.01 indicate significant difference from LPS alone (unpaired t test).
All references cited are hereby incorporated by reference. The present invention is illustrated by way of the foregoing description and examples. The foregoing description is intended as a non-limiting illustration, since many variations will become apparent to those skilled in the art in view thereof. It is intended that all such variations within the scope and spirit of the appended claims be embraced thereby.
2
22 base pairs
nucleic acid
single
linear
DNA (genomic)
1
AGTTGAGGGG ACTTTCCCAG GC 22
22 base pairs
nucleic acid
single
linear
DNA (genomic)
2
AGTTGAGGCG ACTTTCCCAG GC 22
Changes can be made in the composition, operation and arrangement of the method of the present invention described herein without departing from the concept and scope of the invention as defined in the following claims:
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The present invention is directed to a method for inhibiting expression of either iNOS or COX-2, or both in mammals using flavone compounds, and pharmaceutically acceptable salts thereof. The present invention is also directed to a method of activating K + channels in mammals; as well as methods for treating septic shock, for inhibiting expression of angiotensin converting enzyme, for treating or preventing aneurysms and for reducing inflammation and related pathological changes using these compounds. Presently preferred compounds are oroxylin A (5,7-dihydroxy-6-methoxy flavone) and wogonin (5,7-dihydroxy-8-methoxy flavone).
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BACKGROUND OF THE INVENTION
The term "ceramic fibers" as used herein means polycrystalline metal oxide fibers having a high melt temperature typically in excess of 3,000° F. Such fibers generally contain aluminum oxide or calcium oxide and silica, as well as smaller amounts of other metal oxides, such as ferric, titanium and magnesium. A typical ceramic fiber will comprise, for example, in excess of 30% aluminum or calcium oxide, in excess of 45% silica, with any remainder as other metallic oxides. Specific examples of compositions for ceramic fibers include the following:
______________________________________ EXAMPLE 1 EXAMPLE 2 EXAMPLE 3______________________________________Al.sub.2 O.sub.3 47.5% 45% 10%CaO 35%SiO.sub.2 49% 52% 45%Fe.sub.2 O.sub.3 1% 1% 3%TiO.sub.2 2% 2% 2%Misc. MetalOxides MgO 0.5% Trace .5%______________________________________
The fibers are made by several processes, one of which involves the formation of a melt at oven in excess of 3200° F., and then contacting a spinning or slinging wheel or high velocity gas with the melt to produce individual fibers, which are then cooled and collected. Various compositions for ceramic fibers and methods for making the same are described in the following patents: U.S. Pat. Nos. 2,557,834; 2,674,539; 2,699,397; 2,710,261; 2,714,622; and 3,007,806.
Ceramic fibers of the foregoing nature have a variety of present and proposed uses, particularly as fillers and insulating media. The use of such fibers, however, has been somewhat limited because of their limited flexibility, strength, abrasion resistance and most critically their lack of dispersibility in water or other liquids. For example, ceramic fiber of typical size distribution as currently produced will not form a stable slurry or dispersion in water, even with the addition of surface active agents and requires high shear agitation to produce even moderately uniform suspensions. Due to the shear sensitivity of this class of fibers, the fiber length is reduced drastically in the process which reduces their ultimate produce thermal value and product strength.
The ability to disperse fiber would be desirable from the viewpoint of producing a better variety of shapes or forms with improved physical properties of strength and uniformity. Such products include papers, webs, foams, molded shapes, small yarns and the like.
SUMMARY OF THE INVENTION
The present invention resides in the application of effective amounts of an organic coupling agent, either a silane or titanate, and also preferably a surfactant to the surface of ceramic fibers while hot, both preferably applied as the fibers as being produced. The coupling agent and surfactant are preferably applied as a mixture by misting or spraying a dilute solution thereof onto the fiber at a relatively low rate, less than 10% by weight, of application. Thereafter, the fibers are allowed to cool and exhibit superior properties over untreated fibers, including improved flexibility, strength, abrasion resistance and dispersibility.
Upon application, the coupling agent bonds to the fiber and results in an ionic surface on the fiber. The surfactant remains as a residue on the fiber and serves to provide additional anionic or cationic ions respectively, for improved dispersibility, reduced surface tension, and other improved qualities.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Ceramic fibers as defined herein are conventionally manufactured by providing a molten mass of the ceramic material, and then spinning, slinging, or high velocity gas impinging, the mass into a chamber under conditions to form individual fibers. Various processes for producing such fibers are well known to those skilled in the art.
In accordance with the process of the present invention, an ionic coating is applied to the fiber shortly after the formation thereof and before the fiber has cooled to room temperature. Alternatively, but less desirably, fiber may be heated to the desired temperature and the coating applied.
The temperature at which the coating is applied is dependent upon numerous factors, including cooling rate, dilution and vaporization rate of the solvent containing the coating, reactivity rate between the particular fiber and particular coating materials, and atmosphere in the cooling chamber. Preferably, the temperature of the fiber after the coating has been applied and solvent evaporated is in excess of 275° F. The maximum temperature of application is preferably less than the decomposition temperature for any of the components used in the coating, but typically, the finished temperature of the coated fiber should not exceed 525° F.
The coating of the present invention comprises a mixture of a hydrolyzable silane or titanate coupling agent and an ionic surfactant. Suitable surfactants, for example, include carboxy acids, sulfuric esters, alkane sulfonates, alkyl aromatic sulfonates and others. Specific examples include sodium oleate, sodium lauryl sulfate, and polyethylene glycol alkyl aryl ether. The surfactant used is preferably dispersible in water and aids or enhances the ability of the fiber to be dispersed and also improves handling properties of the dry fiber.
The coupling agents used in the present invention are silanes, titanates, or mixtures thereof. Suitable silanes, for example, include hydrolyzable, allyl, amino-alkyl, beta chloropropyl, epoxy mercapto, methacrylato, phenyl, thioalkyl, thio-alkaryl and vinyl silanes, their hydrolysis products and polymers of the hydrolysis products and mixtures thereof. Specific detailed evaluations conducted on the list of silane coupling agents below, indicates the use of gamma-Methacryloxypropyltrimethoxysilane and/or vinyl-tris (2-methoxyethoxy) silane in combination with sodium oleate to give the best overall results of the silanes tested.
______________________________________TYPE DESCRIPTION______________________________________1. A-1100 gamma-Aminopropyltriethoxysilane2. A-1160 gamma-Ureidopropyltriethoxysilane3. A-1120 N-beta-(aminoethyl)gamma- aminopropyltrimethoxysilane4. A-174 gamma-Methacryloxy- propyltrimethoxysilane5. A-172 Vinyl-tris(2-methoxyethoxy) silane6. A-151 Vinyltriethoxysilane7. A-186 beta-(3,4-Epoxycyclohexy) ethyltrimethoxysilane8. A-187 gamma-Glycidoxypro- pyltrimethoxysilane9. A-189 gamma-Mercaptopro- pyltrimethoxysilane______________________________________
Of other major groups of coupling agents, titanates also produce various degrees of benefit for the aforementioned and described application. Of the list of those evaluated, which follows, four were especially effective; titanium di(dioctylpyrophosphate) oxyacetate, isopropyl tri(dioctylpyrophosphate) titanate, titanium dimethacrylate oxyacetate, and titanium diacrylate oxyacetate, or their ethoxylated ester forms. Suitable titanate coupling agents tested include:
______________________________________TITANATECOUPLINGAGENT DESCRIPTION______________________________________KR-TTS isopropyl, triisostearoyl titanateKR-201 diisostearoyl, ethylene titanateKR-33BS isopropyl trimethacryl titanateKR-133BS titanium dimethacrylate, oxyacetateKR-39BS isopropyl, triacryl titantateKR-139BS titanium diacrylate, oxyacetateKR-34S & BS isopropyl tricumylphenyl titanateKR-134S & BS titanium di(cumylphenolate) oxyacetateKR-44 isopropyl, tri(N ethylamino-ethylamino) titanateKR-52S isopropyl, tri(2-aminobenzoyl) titanateKR-63S isopropyl, tri(tetraethylenetriamine) titanateKR-66S isopropyl, tri(3-mecaptopropionyl) titanateKR-27S isopropyl triricinoyl titanateKR-9S isopropyl, tridodecylbenzenesulfonyl titanateKR-12 isopropyl, tri(dioctylphosphato) titanateKR-112S titanium di(dioctylphosphate) oxyacetateKR-212 di(dioctylphosphato) ethylene titanateKR-38S isopropyl tri(dioctylpyrophosphato) titanateKR-138S titanium di(dioctylpyrophosphate) oxyacetateKR-238S di(dioctylpyrophosphato) ethylene titanateKR-58FS tri(butyl, octyl pyrophosphato) isopropyl titanateKR-158FS titanium di(butyl, octyl pyrophosphate) de (dioctyl, hydrogen phosphite)oxyacetateKR-62ES di(butyl, methyl pyrophosphato), isopropyl titanate mono(dioctyl, hydrogen) phosphiteKR-262ES di(butyl, methyl pyrophosphato) ethylene titanate mono(dioctyl, hydrogen phosphate)KR-36C tetraisopropyl di(tridecylphosphito) titanateKR-41B tetraisopropyl, di(dioctylphosphito) titanateKR-46B tetraoctyloxytitanium di(ditridecylphosphite)KR-55 tetra(2,2 diallyloxymethyl-1 butoxy titanium di(di-tridecyl) phosphite______________________________________
The proportions of the coupling agent and surfactant may vary with respect to each other. Preferably, the mixture is applied as a dilute aqueous spray containing from about 1 or about 6 percent each of the coupling agents and surfactant and the remainder as water and/or suitable solvent. The ratio of applied coating to fiber, by weight, is preferably less than 10 percent by weight or preferably from about 1:200 to about 1:20.
Specific ceramic fiber spray formulation examples include:
EXAMPLE A
2% sodium oleate aqueous solution to which is added and dissolved A-174 silane coupling agent at a mixed product composition of 3%.
EXAMPLE B
3% saponified mixed fatty acids aqueous solution (including linoleic, palmitic and elaidic acid) to which is added A-172 silane coupling agent to produce a concentration of 1.5% A-172.
After application of the coupling agent and surfactant, the fiber is allowed to cool. Thereafter, the surface modified fiber may be dispersed in water with the aid of mixing and optional addition of surfactants or other dispersing aids.
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Hot ceramic fibers, preferably those freshly manufactured, are provided with a coating containing an ionic coupling agent such as either a silane or titanate coupling agent and preferably also a surfactant. The coated fiber is then allowed to cool. The fiber, with the silane or titanate bonded therein has greatly improved flexibility, strength, abrasion resistance and most importantly dispersibility in water.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a variable displacement compressor that changes its discharge displacement by adjusting the inclination of a swash plate. More particularly, the present invention relates to a variable displacement compressor that stops drawing in refrigerant gas from an external refrigerant circuit and circulates the residual gas therein when the inclination of its swash plate is minimum.
2. Description of the Related Art
Vehicles typically have compressors employed in air conditioning systems. A compressor having a controllable displacement is desirable for accurately controlling the interior air temperature to make the ride comfortable for the vehicle's passengers. There is a type of compressor that is provided with a swash plate, which is tiltably supported on a rotary shaft, cylinder bores, and reciprocal pistons, which are accommodated in the bores. The inclination of the swash plate is controlled based on the difference between the pressure in a crank chamber and the pressure in the cylinder bores. The stroke of each piston is varied by the inclination of the swash plate.
Such a compressor does not employ an electromagnetic clutch to selectively connect or disconnect the shaft of the compressor with an external drive source to transmit drive force. The external drive source is directly connected to the rotary shaft. This structure eliminates shocks that would otherwise be produced by the ON/OFF action of such a clutch. Such a compressor improves the riding comfort of the vehicle's passengers. The structure also reduces the overall weight of the refrigeration system and thus reduces the manufacturing cost.
In such a clutchless system, the compressor is operated even when cooling is not necessary. With such compressors, it is important that, when cooling is unnecessary, the discharge displacement be reduced as much as possible to prevent formation of frost in the evaporator. If cooling becomes unnecessary or if frost starts forming, the circulation of the refrigerant gas between the compressor and the external refrigerant circuit should be stopped. As shown in FIG. 12, a typical compressor has a shutter 150 that blocks the gas from an external refrigerant circuit (not shown) from flowing into a suction chamber 154. This stops the circulation of the refrigerant gas.
As shown in FIG. 12, the hollow cylindrical shutter 150 is slidably accommodated in a shutter chamber 152, which is defined in a cylinder block 151. The shutter 150 moves along the axis of a rotary shaft 156 in accordance with the inclination of a swash plate 157, which is supported by the drive shaft 156. A rear housing 158 is coupled to the rear end of the cylinder block 151 with a valve plate 159 provided in between. The rear housing 158 includes a suction chamber 154, a discharge chamber 160, and a suction passage 154. The suction chamber 153 is connected to the external refrigerant circuit. The suction passage 153 is communicated with the external refrigeration circuit via the shutter chamber 152. A positioning surface 155 is defined on the cylinder block 151 between the shutter chamber 152 and the suction passage 153.
A plurality of cylinder bores 163 extend through the cylinder block 151. A piston 161 is coupled to the swash plate 157 by a pair of shoes 162 and one piston 161 is accommodated in each bore 163. The swash plate 157 rotates integrally with the rotary shaft 156. The rotating movement of the swash plate 157 is converted to linear reciprocating movement of each piston 161 in the associated cylinder bore 163. The stroke of the pistons 161 corresponds to the inclination of the swash plate 157.
When the swash plate 157 is fully inclined with respect to the axis of the shaft 156, in which state the compressor displacement becomes maximal, the shutter 150 is moved to an opening position as shown by the solid lines in FIG. 12. The shutter 150 in the opening position enables communication between the suction passage 153 and the suction chamber 154. Therefore, as the piston 161 reciprocates, the refrigerant gas is drawn into each cylinder bore 163 from the external refrigeration circuit via the suction passage 153 and the suction chamber 154. The gas is then compressed in the cylinder bore 163. The compressed gas is discharged to the external refrigeration circuit via the discharge chamber 160.
As the inclination of the swash plate 157 becomes smaller from this state, the shutter 150 moves toward the positioning surface 155. When the inclination of the swash plate becomes minimal, causing the compressor displacement to be minimal, the shutter 150 abuts against the positioning surface 155 as shown by the double-dotted lines in FIG. 12. The abutment restricts the movement of the shutter 150 toward the positioning surface 155 and positions the shutter 150 at a closed position such that the shutter 150 disconnects the suction passage 153 from the suction chamber 154. Accordingly, the refrigerant gas stops flowing into the suction chamber 154 from the external refrigeration circuit. This stops the circulation of refrigerant gas between the external refrigeration circuit and the compressor.
In the above compressor, refrigerant gas is discharged from the cylinder bores 163 into the discharge chamber 160 and then drawn into the crank chamber 164 when the refrigerant gas in the external refrigerant circuit is hindered from flowing into the suction chamber 154. The refrigerant gas in the crank chamber 164 flows into the suction chamber 154 and is then drawn into each cylinder bore 163 during the suction stroke of the piston 161. In other words, a circulation passage is formed in the compressor when the flow of the refrigerant gas from the external refrigerant gas into the suction chamber 154 is stopped. The circulation passage, through which refrigerant gas circulates, is defined between the cylinder bores 163, discharge chamber 160, crank chamber 164, the suction chamber 154 and the cylinder bores 163. Refrigerant gas includes mist-like lubricant. The lubricant circulates through the circulation passage suspended in the refrigerant gas to lubricate various parts in the compressor.
A valve plate 159 has a suction port 165 and a discharge port 166. The plate 159 also includes a flapper type suction valve 167 and a flapper type discharge valve 168 for selectively opening and closing the ports 165 and 166. The flapper type valves 167, 168 close the ports 165, 166, respectively. Therefore, in order to open the ports 165, 166, the valves 167, 168 should be flexed against their elasticity. The mist-like lubricant in the refrigerant gas liquefies and adheres to the valves 167, 168 and also on the ports 165, 166 at sections surrounding the port valves, where the valves 167, 168 come into contact with the ports 165, 166, respectively. The liquefied lubricant adheres the valves 167, 168 to the valve plate 159 and makes it difficult to open the valves 167, 168.
When its inclination becomes small, the swash plate 157 moves toward the rear end of the compressor (right in FIG. 12) along the axis of the rotary shaft 156. The movement of the swash plate 157 pushes the shutter 150 toward the positioning surface 155 and the pistons 161 toward the rear end of the compressor. Therefore, the piston 161 moves relatively close to the valve plate 159 with a short stroke when the swash plate 157 is minimally inclined. In this state, if the valves 168, 167 adhere to the valve plate 159 and liquefied lubricant resides in the cylinder bore 163, the lubricant may not be discharged from the bores 163. The liquefied oil in each bore 163 also obstructs the piston 161 from moving close to the valve plate 159. This affects the movement of the swash plate 157 and hinders it from moving to its rear end position, where the inclination angle becomes minimal. Accordingly, the shutter 150 is hindered from moving to the closed position for disconnecting the suction passage 153 and the suction chamber 154. This causes the refrigerant gas in the external refrigerant circuit to leak into the suction chamber 154.
In this case, if refrigerant gas in the external refrigerant circuit is liquefied by a decrease in ambient temperature, the liquefied refrigerant flows into the compressor via the suction passage 153. The liquefied refrigerant washes away the lubricant inside the compressor. When operation of the compressor is resumed with a large displacement, the lubricant in the compressor in the liquefied refrigerant is drawn into the external refrigerant circuit. Thus, lubrication in the compressor becomes less than desirable. The lubricant also flows into an evaporator in the external refrigerant circuit and thereby decreases the cooling efficiency.
SUMMARY OF THE INVENTION
Accordingly, it is an objective of the present invention to provide a variable displacement compressor that prevents liquefied refrigerant in an external refrigerant circuit from flowing into the compressor when the compressor's displacement is minimal.
To achieve the above objects, the compressor according to the present invention has a cam plate located in the crank chamber and mounted on the drive shaft. The cam plate is tiltable between a maximum inclined angle position and a minimum inclined angle position with respect to a plane perpendicular to an axis of the drive shaft according to the difference between the pressures in the crank chamber and a cylinder bore. The cam plate varies the stroke of the piston in the cylinder bore based on the inclination thereof to control the displacement of the compressor. A shutter member is movable between a first position where the shutter member connects the refrigerant circuit with the suction chamber and a second position where the shutter member disconnects the external circuit from the suction chamber in response to the inclination of the cam plate. The cam plate moves the shutter member to the second position when the cam plate is at the minimum inclined angle position to minimize the displacement of the compressor. A valve plate is located between the cylinder bore and a gas chamber. The gas chamber is either the suction chamber or the discharge chamber. The valve plate has a port that connects the cylinder bore with the gas chamber and a valve that has open and shut positions. A passage is defined between the valve plate and the valve when the valve is shut to connect the cylinder bore with the gas chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:
FIG. 1 is a cross-sectional view illustrating a variable displacement compressor according to first and second embodiments of the present invention;
FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1;
FIG. 3 is an enlarged partial cross-sectional view illustrating the valve plate of the first embodiment;
FIG. 4 is a partial cross-sectional view taken along line 4--4 of FIG. 3;
FIG. 5 is a cross-sectional view illustrating the compressor in FIG. 1 operating with minimal displacement;
FIG. 6 is an enlarged partial cross-sectional view illustrating the valve plate of the second embodiment;
FIG. 7 is a partial cross-sectional view taken along line 7--7 of FIG. 6;
FIG. 8 is an enlarged view illustrating a discharge valve of another embodiment;
FIG. 9 is an enlarged view illustrating a suction valve of another embodiment;
FIG. 10 is an enlarged partial cross-sectional view illustrating a valve plate according to another embodiment;
FIG. 11 is an enlarged partial cross-sectional view illustrating a valve plate according to another embodiment; and
FIG. 12 is a partial cross-sectional view illustrating a prior art variable displacement compressor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A variable displacement compressor according to a first embodiment of the present invention will be described below with reference to FIGS. 1 through 5.
As shown in FIG. 1, a cylinder block 11 constitutes a part of a compressor housing. A front housing 12 is secured to the front end of the cylinder block 11. A rear housing 13 is secured to the rear end of the cylinder block 11 with a valve plate 14 arranged in between. A crank chamber 25 is defined in the front housing 12. A plurality of bolts 15, which extend through the front housing 12, the cylinder block 11, and valve plate 14, are screwed into the rear housing 13. The bolts 15 fix the front housing 12 and the rear housing 13 to the front end face and the rear end face of the cylinder block 11.
A rotary shaft 16 is rotatably supported by a pair of radial bearings 17, 18 and extends through the center of the cylinder block 11 and the front housing 12. A lip seal 19 is located between the rotary shaft 16 and the front housing 12. The lip seal 19 seals the crank chamber 25. The front end of the rotary shaft 16 is secured to a pulley 20. The pulley 20 is directly coupled to a drive source such as a vehicle's engine by a belt 21. An angular bearing 22 is placed between the pulley 20 and the front housing 12. The angular bearing 22 carries thrust and radial loads.
A substantially disk-like swash plate 30 is supported by the rotary shaft 16 in such a way as to be slidable along and tiltable with respect to the axis of the shaft 16. The swash plate 30 is provided with a pair of guide pins 31, each having a spherical body at its distal end. A rotor 26 is fixed to the rotary shaft 16 in the crank chamber 25. The rotor 26 rotates integrally with the rotary shaft 16. A thrust bearing 27 is arranged between the rotor 26 and the front housing 12. The rotor 26 has a support arm 28 protruding toward the swash plate 30. A pair of guide holes 29 are formed in the arm 28. Each guide pin 31 is slidably fit into the corresponding guide hole 29. The cooperation of the arm 28 and the guide pins 31 permits the swash plate 30 to rotate together with the rotary shaft 16. The cooperation also guides the tilting of the swash plate 30 and the movement of the swash plate 30 along the axis of the rotary shaft 16.
A plurality of cylinder bores 23 are formed extending through the cylinder block 11 about the rotary shaft 16. The bores 23 are arranged parallel to the rotary shaft 16 with a predetermined interval between each adjacent bore 23. A single-headed piston 24 is housed in each bore 23. A pair of semispheric shoes 33 is fit between each piston 24 and the swash plate 30. A semispheric portion and a flat portion are defined in each of shoes 33. Each semispheric portion slidably contacts each piston 24 while the flat portion slidably contacts the swash plate 30. The swash plate 30 rotates integrally with the rotary shaft 16. The rotating movement of the swash plate 30 is transmitted to each piston 24 through the shoes 33 and converted to a linear reciprocating movement of each piston 24 in the associated cylinder bore 22.
A shutter chamber 34 is defined in the center of the cylinder block 11, extending along the axis of the rotary shaft 16. A suction passage 35 is defined in the center portion of the rear housing 13 and the valve plate 14, extending along the axis of the rotary shaft 16. The suction passage 34 is communicated with the shutter chamber 35. The suction passage 35 is coupled to an external refrigerant circuit 37 via a suction muffler 36. The external refrigerant circuit 37 includes a condenser 38, an expansion valve 39, and an evaporator 40.
An annular suction chamber 41 is defined in the rear housing 13. The suction chamber 41 is communicated with the shutter chamber 34 via a communication hole 42. An annular discharge chamber 43 is defined around the suction chamber 41 in the rear housing 13. A discharge muffler 44 is provided on the top portion of the cylinder block 11. The discharge chamber 43 is connected to the external refrigerant circuit 37 via the discharge muffler 44.
Suction valve mechanisms 45 are formed on the valve plate 14. Each suction valve mechanism 45 corresponds to one of the cylinder bores 23. As each piston 24 moves from the top dead center to the bottom dead center in the associated cylinder bore 23, refrigerant gas in the suction chamber 41 is drawn into the cylinder bore 23 through the associated suction valve mechanism 45. Discharge valve mechanisms 46 are formed on the valve plate 14. Each discharge valve mechanism 46 corresponds to one of the cylinder bores 23. As each piston 24 moves from the bottom dead center to the top dead center in the associated cylinder bore 23, the refrigerant gas is compressed in the cylinder bore 23 and discharged to the discharge chamber 43 through the associated discharge mechanism 46.
A hollow cylindrical shutter 47 is accommodated in the shutter chamber 34 in such a way as to be slidable along the axis of the rotary shaft 16. A coil spring 48 is located between the shutter 47 and the inner wall of the shutter chamber 34. The coil spring 48 urges the shutter 47 toward the swash plate 30.
The rear end of the rotary shaft 16 is inserted in the shutter 47. The radial bearing 18 is located between the rear end of the rotary shaft 16 and the inner wall of the shutter 47. The radial bearing 18 receives radial loads applied to the rotary shaft 16. The radial bearing 18 is fixed to the inner wall of the shutter 47. Therefore, the radial bearing 18 moves with the shutter 47 along the axis of the rotary shaft 16.
A thrust bearing 49 is located between the shutter 47 and the swash plate 30 in such a way as to be slidable along the axis of the rotary shaft 16. A pair of convex protrusions 50 are formed on the rear end surface of the swash plate 30. Each protrusion 50 contacts the front race of the thrust bearing 49. The thrust bearing 49 receives loads in the axial direction between the shutter 47 and the swash plate 30.
A positioning surface 10 is formed on the valve plate 14 between the suction chamber 34 and the suction passage 35. The abutment of the rear end face of the shutter 47 and the positioning surface 10 restricts the backward movement (toward the right, as viewed in FIG. 1) of the shutter 47 and disconnects the communication of the suction passage 35 and the shutter chamber 34.
As the swash plate 30 slides backward, its inclination becomes small. As the swash plate 30 slides backward, it pushes the shutter 47 with the thrust bearing 49. This moves the shutter 47 against the tension of the coil spring 48 toward the positioning surface 10. When the swash plate 30 reaches the minimum inclination as shown in FIG. 5, the rear end face of the shutter 47 contacts the positioning surface 10 and becomes located at a closed position. At the closed position, the shutter 47 disconnects the suction passage 35 from the shutter chamber 34. This prevents the swash plate 30 from further inclining from the minimum inclination and stops the flow of refrigerant gas from the external refrigerant circuit 37 to the suction chamber 41. This causes the displacement of the compressor to become minimum. The minimum inclination of the swash plate 30 is slightly larger than zero degrees. Zero degrees refers to the angle of the swash plate's inclination when it is perpendicular to the axis of the rotary shaft 16.
As the swash plate 30 moves from the minimum inclination position in FIG. 5 toward the maximum inclination, the shutter 47 is separated from the positioning surface 10 by the coil spring 48. The shutter 47 comes to an opening position shown in FIG. 1 to communicate the suction chamber 35 with the shutter chamber 34. This draws the refrigerant gas into the suction chamber 41 from the external refrigerant circuit 37 via the suction passage 35. Accordingly, the displacement of the compressor becomes maximal. The abutment of a projection 51 projecting from the front end face of the swash plate 30 against the rotor 26 prevents the inclination of the swash plate 30 beyond the predetermined maximum inclination.
A coil spring 66 is place between the rotor 26 and the swash plate 30. The coil spring 66 urges the swash plate 30 backward (in other words, in a direction that decreases the inclination of the swash plate 30).
A passage 52 is defined in the central portion of the rotary shaft 16. The passage 52 has an inlet 53 connected with the crank chamber 25 and outlet connected with the interior of the shutter 47. A pressure release hole 54 is formed in the peripheral wall of the shutter 47 near its rear end. The hole 54 communicates the interior of the shutter 47 with the shutter chamber 34. Refrigerant gas in the crank chamber 25 is released into the suction chamber 41 through the passage 52, the interior of the shutter 47, the pressure release hole 54, the shutter chamber 34, and the communication hole 42.
A supply passage 55 is defined in the rear housing 13, valve plate 14, and the cylinder block 11. The supply passage 55 connects the discharge chamber 43 to the crank chamber 25. An electromagnetic valve 56 is arranged in the rear housing 13 and located midway in the supply passage 55. When the solenoid 57 of the electromagnetic valve 56 is excited, the supply passage 55 is closed. When the solenoid 57 is de-excited, the supply passage 55 is opened. Refrigerant gas in the discharge chamber 43 flows into the crank chamber 25 via the supply passage 55.
The structure of the suction valve mechanism 45 and the discharge valve mechanism 46 will be described below.
As shown in FIGS. 1 and 2, the valve plate 14 includes a main plate 14a, a first plate 14b, and a second plate 14c. The main plate 14a is placed between the first plate 14b and the second plate 14c. A third plate 64 is provided on the second plate 14c. Suction ports 58 are formed on the main plate 14a, second plate 14c, and the third plate 64. Each suction port 58 corresponds to one of the cylinder bores 23. Flapper type suction valves 59 are formed on the first plate 14b. Each suction valve 59 corresponds to one of the suction ports 58. Discharge ports 60 are formed on the main plate 14a and the first plates 14b. Each discharge port 60 corresponds to one of the cylinder bores 23. Flapper type discharge valves 61 are formed on the second plate 14c. Each discharge valve 61 corresponds to one of the discharge ports 60. Retainers 65 are formed on the third plate 64. Each retainer 65 corresponds to one of the discharge valves 61 and controls the opening of the valve 61.
As shown in FIGS. 3 and 4, a frosted-glass-like rough surface 62 is formed around each discharge port 60 (in other words, the area that each discharge valve 61 contacts) on the main plate 14a. The rough surface 62 is formed, for example, through shot blasting. The rough surface 62 defines a slight space connecting the cylinder bores 23 with the outside of the associated bore 62. The rough surface 62 prevents the discharge valve 61 from adhering to the main plate 14a.
The surface roughness of the main plate 14a is 4 μmRz or less. The surface roughness of the rough surface 62 on the main plate 14a is preferably between 5 μmRz and 35 μmRz. More preferably, the surface roughness of the rough surface 62 is between 10 μmRz and 20 μmRz.
The rough surface 62 defines a slight space between the main plate 14a and each closed discharge valve 61. The space allows the lubricant and refrigerant gas in each cylinder bore 23 to be discharged into the discharge chamber 43. This enables the shutter 47 to be securely moved to the closed position where the shutter 47 disconnects the suction passage 35 from the suction chamber 41. Accordingly, the lower limit for the surface roughness of the rough surface 62 corresponds to a minimum value that initiates the discharge of the lubricant and refrigerant gas in each cylinder bore 23 to the discharge chamber 43 through the space between the main plate 14a and each discharge valve 61. The space between the main plate 14a and each closed discharge valve 61 causes the refrigerant gas in the associated cylinder bore 23 to leak into the discharge chamber 43. The space may also reverse the flow of refrigerant gas from the cylinder bores 23 to the discharge chamber 43. Therefore, the space may degrade the compression capability of the compressor. Accordingly, the upper limit for the surface roughness of the rough surface 62 corresponds to a maximum value that enables the compressor to satisfy the required compression capability.
As shown in FIGS. 1, 2 and 5, a check valve 63 is placed between the discharge muffler 44 and the external refrigerant circuit 37. The check valve 63 includes a valve body 67, a spring 68 and a spring seat 69. The check valve 63 allows compressed refrigerant gas to be discharged from the discharge muffler 44 to the external refrigerant circuit 37, while stopping any reverse flow of liquefied refrigerant from the external refrigerant circuit 37 into the muffler 44.
The operation of the above compressor will now be described.
FIG. 1 shows the solenoid 57 in the electromagnetic valve 56 in an excited state. In this state, the supply passage 55 is closed. Therefore, highly pressurized refrigerant gas in the discharge chamber 43 is not supplied to the crank chamber 25. Refrigerant gas in the crank chamber 25 flows into the suction chamber 41 via the passage 52 and the pressure release hole 54. This causes the pressure in the crank chamber 25 to approach the low pressure of the suction chamber 41, i.e., the suction pressure. This maximizes the inclination of the swash plate 30. The displacement of the compressor thus becomes maximum. When the displacement is maximum, the high pressure in the discharge chamber 43 moves the valve body 67 of the check valve 63, provided at the outlet of the discharge muffler 44, toward the spring seat 69 against the force of the spring 68. This opens the check valve 63 and releases the high pressure refrigerant gas into the external refrigerant circuit through the discharge muffler 44.
During operation of the compressor, fluctuation of the suction pressure caused by fluctuating cooling loads changes the difference between the pressure in the crank chamber 25 and the pressure in each cylinder bore 23, both of which act on each piston 24. The changes of the pressure difference alters the inclination of the swash plate 30. This adjusts the stroke of the pistons 24. As a result, the displacement of the compressor is adjusted to an appropriate level.
When the compressor is operated with the inclination of the swash plate 30 being maximum, the temperature of the evaporator 40 in the external refrigerant circuit 37 decreases gradually as the cooling load of the compressor becomes small. When the temperature of the evaporator 40 drops below the frost forming temperature, the solenoid 57 is de-excited to open the electromagnetic valve 56, as shown in FIG. 5. This draws the high pressure refrigerant gas in the discharge chamber 43 into the crank chamber 25 via the passage 55. Accordingly, the pressure in the crank chamber 25 becomes higher. This moves the swash plate 30 toward the minimum inclination from the maximum inclination. The displacement of the compressor becomes minimum when the swash plate 30 reaches the minimum inclination. This decreases the pressure in the discharge chamber 43. Accordingly, the valve body 67 of the check valve 63 is moved away from the spring seat 69 by the force of the spring 68. This closes the check valve 63 and disconnects the discharge muffler 44 from the external refrigerant circuit 37.
When the inclination becomes small, the swash plate 30 pushes the shutter 47 with the thrust bearing 49 toward the positioning surface 10. The abutment of the rear end face of the shutter 47 and the positioning surface 10 disconnects the suction chamber 41 from the suction passage 35. Accordingly, refrigerant gas stops flowing into the suction chamber 41 from the external refrigerant circuit 37. The circulation of refrigerant gas between the external refrigerant circuit 37 and the compressor is thus stopped.
The inclination of the swash plate 30 becomes minimal when the shutter 47 contacts the positioning surface 10. Since the minimum inclination of the plate 30 is slightly greater than zero degrees, refrigerant gas continues being discharged to the discharge chamber 43 from the cylinder bore 23 when the inclination of the swash plate is minimum. This allows the compressor to operate with its displacement being minimum. Refrigerant gas discharged to the discharge chamber 43 is drawn into the cylinder bore 23 again via the supply passage 55, the crank chamber 25, the passage 52 and the pressure release hole 54.
In other words, when the swash plate 30 is minimally inclined, refrigerant gas circulates through a closed circulating passage formed in the compressor. The closed passage includes the discharge chamber 43, the supply passage 55, the crank chamber 25, the passage 52, the pressure release hole 54, suction chamber 41, and the cylinder bore 23. The circulation lubricates each part in the compressor with lubricant suspended in the refrigerant gas.
An increase in cooling load when the compressor is operated with the inclination of the swash plate 30 being minimum gradually increases the temperature of the evaporator 40 in the external refrigerant circuit 37. When the temperature of the evaporator 40 exceeds the frost forming temperature, the solenoid 57 is excited to close the electromagnetic valve 56 as shown in FIG. 1. This stops the flow of refrigerant gas in the discharge chamber 43 into the crank chamber 25. Refrigerant gas in the crank chamber 25 flows into the suction chamber 41 via the passage 52 and the pressure release hole 54. This results in a pressure decrease in the crank chamber 25, thereby moving the swash plate 30 from the minimum inclination toward the maximum inclination.
As the inclination of the swash plate 30 becomes smaller, the shutter 47 moves slowly away from the positioning surface 10 due to the force of the coil spring 48. The movement of the shutter 47 gradually increases the volume of refrigerant gas drawn into the suction chamber 41 from the external refrigerant circuit 37 via the suction chamber 35. Accordingly, the volume of refrigerant gas drawn into the cylinder bore 23 from the suction chamber 41 increases gradually. This results in a gradual increase in the compressor's displacement. When the inclination of the swash plate 30 becomes the maximum, the displacement of the compressor becomes maximum. This increases the pressure in the discharge chamber 43, thereby opening the check valve 63 provided at the outlet of the discharge muffler 44. Accordingly, high pressure refrigerant gas starts flowing toward the external refrigerant circuit 37 from the discharge muffler 44.
The rough surface 62 is formed around each discharge port 60 (where each discharge valve 61 contacts) on the main plate 14a. Even when the valve 61 closes the port 60, slight space is defined between the rough surface 62 and the valve 61. Thus, the discharge valve 61 is prevented from being adhered to the main plate 14a. opening of the valve 61 is thus facilitated. Further, when the swash plate 30 moves toward the valve plate 14 as its inclination becomes smaller, lubricant and refrigerant gas in the cylinder bore 23 are smoothly discharged to the discharge chamber 43 through the space between the main plate 14a and the discharge valve 61. This allows the pistons 24 to move closer to the valve plate 14 (i.e., the position where the compressor displacement becomes minimum). This movement allows the swash plate 30 to slide to the rearmost position where its inclination becomes minimum. Accordingly, the shutter 47 is moved to the position to disconnect the suction chamber 41 from the suction passage 35. This prevents leakage of liquefied refrigerant from the external refrigerant circuit 37 to the suction chamber 41.
When the displacement of the compressor is minimum, the pressure in the discharge chamber 43 decreases. This closes the check valve 63 and disconnects the external refrigerant circuit 37 from the discharge muffler 44 and prevents leakage of liquefied refrigerant from the external refrigerant circuit 37 to the discharge muffler 44.
The above described embodiment has the following advantages:
(a) When the displacement of the compressor is minimum, liquefied refrigerant in the external refrigerant circuit 37 is prevented from leaking into the compressor. Therefore, lubricant in the compressor is not washed away by the liquefied refrigerant. When the displacement of the compressor becomes large, the lubricant in the compressor is prevented from leaking into the external refrigerant circuit 37 with the liquefied refrigerant. This ensures lubrication of the compressor. In addition, the structure prevents lubricant from entering the evaporator in the external refrigerant circuit 37, thereby ensuring high cooling efficiency.
(b) The rough surface 62 is formed through shot blasting. The rough surface 62 is limited to the area on the main plate 14a where each discharge valve 61 makes contact. Shot blasting is an efficient method to form a rough surface 62 on a limited area. The resistance of refrigerant gas when it flows between the main plate 14a and the discharge valve 61 may be controlled by changing the roughness of the rough surface 62 to a desirable level. The space defined by the rough surface 62 (in other words, a passage for discharging lubricant in the cylinder bore 23 to the discharge chamber 43) also serves as a restriction. Therefore, during the compressing stroke of each piston before the discharge valve opens, i.e., when each piston moves from the bottom dead center to the top dead center, leakage of refrigerant gas from the cylinder bore 23 to the discharge chamber 43 is minimal. During the suction stroke of each piston, i.e., when each piston moves from the top dead center to the bottom dead center, a reversed flow of high pressure refrigerant gas from the discharge chamber 43 to the cylinder bore is minimal. Therefore, lubricant in the cylinder bores 23 is securely discharged therefrom by a simple structure without degrading the compressing performance of the compressor.
(c) The check valve 63 is located between the exit of the discharge muffler 44 and the external refrigerant circuit 37. This structure prevents liquefied refrigerant from entering into the compressor from the external refrigerant circuit 37 via the discharge muffler 44 when the compressor is not operating or when operating with the displacement in a minimum state.
Second Embodiment
A second embodiment of the present invention will now be described with reference to FIGS. 1, 2, 6 and 7.
In this embodiment, the rough surface 62 is formed around each suction port 58 (where the suction valve contacts) on the main plate 14a through shot blasting. The rough surface 62 defines a slight space between the closed valve 59 and the main plate 14a. This prevents the suction valve 59 from adhering to the main plate 14a. Accordingly, the suction valve 59 may easily be opened.
The surface roughness of the main plate 14a is 4 μmRz or less. The surface roughness of the rough surface 62 on the main plate 14a is preferably between 5 μmRz and 35 μmRz. More preferably, the surface roughness of the rough surface 62 is between 10 μmRz and 20 μmRz.
The lower limit for the surface roughness of the rough surface 62 corresponds to a minimum value that initiates the discharge of the lubricant and refrigerant gas in each cylinder bore 23 to the suction chamber 41 through the space between the main plate 14a and each suction valve 59. The upper limit for the surface roughness of the rough surface 62 corresponds to a maximum value that enables the compressor to satisfy the required compression capability and also satisfy the responsiveness required for the compressor to respond readily when the displacement of the compressor is shifted from the minimum to the maximum value.
When the piston 24 moves toward the valve plate 14 as the inclination of the swash plate 30 becomes small, the pressure in the cylinder bore 23 becomes high. The pressure urges the suction valve 59 toward the main plate 14a. This causes the valve 59 to close the suction port 58. However, the rough surface 62 between the suction valve 59 and the main plate 14a defines a slight space therebetween and prevents the suction valve 59 from adhering to the main plate 14a. Therefore, even if the rough surface 62 is not formed around the discharge port 60, and the discharge valve 61 adheres to the main plate 14a, lubricant and refrigerant gas in the cylinder bore 23 slowly flow into the suction chamber 41 through the space between the main plate 14a and the suction valve 59. Therefore, the shutter 47 is moved to a closed position to disconnect the suction chamber 41 from the suction passage 35. This prevents leakage of liquefied refrigerant from the external refrigerant circuit 37 into the suction chamber.
The compressor according to the second embodiment has the following advantages:
(a) As described in the first embodiment, when the displacement of the compressor is minimum, the shutter 47 is moved to the closed position to disconnect the suction chamber 41 from the suction passage 35. This prevents liquefied refrigerant in the external refrigerant circuit 37 from leaking into the suction chamber 41. Accordingly, lubricant is prevented from being washed away by liquefied refrigerant and leaking into the external refrigerant circuit 37.
(b) The space defined by the rough surface 62 (in other words, a passage for draining lubricant in the cylinder bore 23 to the suction chamber 41) also serves as a restriction. During the compressing stroke of each piston, i.e., when each piston is moving from the bottom dead center to the top dead center, leakage of refrigerant gas in the cylinder bore 23 to the suction chamber 41 is minimum. Therefore, lubricant in the cylinder bore 23 is discharged therefrom by a simple structure without degrading the compressing performance of the compressor.
Although only two embodiments of the present invention have been described above, it should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, the invention may be embodied in the following forms:
(1) In the first embodiment, the rough surface may be formed on the side of the discharge valve 61 facing the main plate 14a as shown in FIG. 8.
(2) In the first embodiment shown in FIGS. 3 and 4, the rough surface 62 may be formed both on the side of the discharge valve 61 facing the main plate 14a and on the side of the main plate 14a facing the valve 61.
(3) In the second embodiment, the rough surface may be formed on the side of the suction valve 59 facing the main plate 14a as shown in FIG. 9.
(4) In the second embodiment shown in FIGS. 6 and 7, the rough surface 62 may be formed both on the side of the suction valve 59 facing the main plate 14a and on the side of the main plate 14a facing the valve 59.
(5) The rough surface 62 may be formed on the side of the main plate 14a in a part facing the suction valve 59 and on the side of the main plate facing the discharge valve 61.
(6) The rough surface 62 may be formed on the side of the suction valve 59 facing the main plate 14a as well as on the side of the discharge valve 61 facing the main plate 14a.
(7) Instead of the rough surface 62 in each embodiment, at least one groove 70 shown by solid lines and two dotted lines in FIG. 10 may be formed on either the main plate 14a or the discharge valve 61. The groove 70 functions as a passage for discharging lubricant from the cylinder bore 23. Similarly, at least one groove 70 shown by solid lines and two dotted lines in FIG. 11 may be formed on either the main plate 14a or the suction valve 59.
(8) Instead of the rough surface 62 in each embodiment, at least one notch may be formed on the main plate 14a, the suction valve 59, or the discharge valve 61. The notch functions as a passage for discharging lubricant from the cylinder bore 23.
(9) Instead of the rough surface 62 in each embodiment, the main plate 14a, the suction valve 59 or the discharge valve 61 may be provided with a knurled surface. The small space defined by the knurled surface functions as a passage for discharging lubricant from the cylinder bore 23.
(10) Instead of the rough surface 62 in each embodiment, the main plate 14a, the suction valve 59, or the discharge valve 61 may be provided with an embossed surface in which a passage is defined for discharging lubricant from the cylinder bore 23.
Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details giving herein, but may be modified within the scope of the appended claims.
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A compressor has a swash (slanting-cam) plate located in a crank chamber and mounted on a drive shaft. The cam plate is tiltable between a maximum inclined angle position and a minimum inclined angle position with respect to a plane perpendicular to an axis of a drive shaft according to a difference between the pressures in the crank chamber and a cylinder bore. The cam plate varies the stroke of a piston in the cylinder bore based on an inclination thereof to control the displacement of the compressor. A shutter member is movable between a first position where the shutter member connects a external circuit with a suction chamber and a second position where the shutter member disconnects the external circuit with the suction chamber in response to the inclination of the cam plate. The cam plate moves the shutter member to the second position when the cam plate is at the minimum inclined angle position to minimize the displacement of the compressor. A valve plate is located between the cylinder bore and a gas chamber. The gas chamber is either the suction chamber or the discharge chamber. The valve plate has a port that connects the cylinder bore with the gas chamber and a valve that has open and shut positions. A passage is defined between the valve plate and the valve when the valve is shut to connect the cylinder bore with the gas chamber.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to plasma ion nitrided (ionitrided) steel plates for use in pressure applications and, more particularly, to an improved highly durable plasma nitrided stainless steel press plate having a high-quality microfinish and methods for the manufacture of same for use in the production of wear resistant decorative laminate.
2. Description of the Prior Art undergone a series of innovations which have lead to greater and greater consumer expectations regarding decorative laminate durability and resistance to mar, scratch, scuff and abrasive wear. Recent efforts to produce such a wear-resistant decorative laminate, especially high pressure decorative laminate, have included the use of extremely hard alumina grit of varying sizes incorporated within the laminate surface. Whereas in the past, formulations for some decorative laminates comprising 6 micron grit as 1 percent by weight in liquid resin and 15 micron grit as 0.5 percent by weight in liquid resin have been utilized, current product trends indicate that formulations having up to 30 micron grit as 9 percent by weight in liquid resin may be necessary to meet consumer laminate wear expectations.
Press plates used to produce decorative laminates are somewhat unique in overall geometry. Manufactured from various grades of steel, particularly stainless steel, the press plate is a flat sheet of rectangular cross section and often has comparatively large longitudinal and transverse dimensions, for example, as large as sixteen and five feet, respectively. The press plates, while thus having large planar surface areas, are only about one eighth of an inch thick.
In a polished condition, the press plates ideally take on the appearance of a mirror-like sheet due to an extremely uniform planar surface, or microfinish, where microscopic discontinuities are minimized. Indeed, in the case of polished press plates, press plate microfinish quality can be determined by viewing reflected images on its surface and scrutinizing the reflected images for optical discrepancies.
Textured press plates, produced by mechanically shot peening or chemically etching their planar surface, or combinations thereof, are usually of much lower gloss than polished plates, such that instrumental gloss measurement rather than visual reflectivity is usually the primary method of characterizing their quality, although certain defects are also evident with visual inspection. Instrumental gloss measurements, in ISO or NEMA gloss units, are typically established by the manufacturer of the laminate based upon consumer expectations. The laminate gloss level in turn is directly related to the gloss of the press plates from which it is produced. The greater the gloss of the plate, the more apparent plate wear becomes.
Also, as a large flat surface used to impart a surface finish to a cellulose supported viscous resin matrix, the press plate must be free from warpage to the maximum extent possible. Warpage generally takes two forms. The first is a regular bow occurring over the entire longitudinal or transverse dimension. At modest levels, this bow is tolerable so long as the press plate assumes a nearly perfect planar orientation under the pressure of the
press, which is normally in the range of 1000 to 1600 psi (6.9 to 11.0 N/mm 2 ). The second type of warp manifests itself as localized distortions and buckling, with variations in the relative height of the press plate from a hypothetically perfect planar surface. This second type o warpage is entirely objectionable as it often does not correct itself under the pressure of the press and thus often results in defective laminate appearance and scrapping of the press plate. Both types of warpage, caused by stress relief or uneven heating, often accompanies efforts to harden the press plates by conventional means.
Thus, the level of manufacturing precision required to fabricate and maintain an overall smooth microfinish and warp-free surface, on both sides of the press plate, is critical. For example, press plates are generally used in a sandwich configuration with two composites of laminate resin-impregnated papers placed therebetween, facing opposite directions. Multiple layers of interleaved laminate material and press plates, so-called "packs" or "books", are then loaded into a press for thermal curing and pressure treatment consolidation. If excess warpage of the first type or any warpage of the second type exists in the press plate, as well as imperfections in the surface microfinish, significantly deleterious effects on the finished decorative laminate appearance will be apparent.
However, the use of alumina grit to improve the wear-resistance of decorative laminate, even in the lower grit sizes and concentrations used in the past, destroys the surface microfinish of the conventional steel press plates heretofore employed to fabricate decorative laminates.
The physical interaction of the formulation grit and the surface of the press plate causes microscratching and resulting lower gloss, haziness, "soft glow" high spot texture wear and at times metal rub-off. Further, as the surface microfinish of the press plates imparts its overall surface finish to the final laminate product, for example, to form a high gloss or textured surface finish in the decorative laminate, any marring of the surface microfinish of the press plates renders the press plates unusable and often requires the damaged press plates to be refurbished at considerable expense or ultimately scrapped.
Attempts to use press plates of greater surface hardness fail to yield a technically and economically viable solution. Conventional polished stainless steel press plates suffer unacceptably severe microscratching after just one press run with any size alumina grit. Textured stainless steel press plates are also easily microscratched by alumina grit. Although not as visually apparent, as with highly polished plates because of their much lower initial gloss level and inherent texture structure, the resultant gradual deterioration in gloss and texture erosion, particularly with use of larger grit sizes and concentrations, necessitates frequent refinishing.
If these stainless steel plates are hardened by conventional heat treating methods, the plates become too brittle, stress fractures can occur, and warpage becomes a significant problem. Chrome plated steel press plates also suffer from severe microscratching after relatively few pressings. Chrome plating and post-baked electroless nickel deposition on stainless steel plates have been used, yet do not satisfactory resolve the problems of grit-related microscratching and plate wear. Further, buffing and polishing operations used for polished plates or shot-blasting refinishing operations used for textured plates tend to remove the thin plated layer unevenly, causing considerable cost to re-plate the surface. The trend toward greater concentrations of even greater sized grit formulations only exacerbates these problems.
Heretofore, ferrous based alloys have been surface hardened by various treatments involving the deposition and diffusion of additional elements and compounds into the base material, notably nitrogen and carbon. However, the wide variety of industrially practiced methods used to case harden stainless steel parts are suspectable to size restrictions and high processing temperatures, often requiring subsequent oil or water quenching, which can result in unacceptable surface finishes and part warpage. Thus, these alternatives are impractical for treating large, relatively thin press plates.
The present invention unexpectedly has found that a concept known as plasma ion nitriding overcomes deficiencies inherent in known press plate hardening means and for the first time enables the manufacture of press plates for use in the production of wear resistant laminates containing concentrations of large alumina grit. Many applications of plasma ion nitriding techniques have been applied to significantly smaller articles or larger articles with relatively small surface to volume ratios where the final microfinish has not been a critical cosmetic aspect of the article, such as via the MPT GmbH Plasma-Triding® process with an automated control and arc discharge suppression system, which regulates the plasma input energy for better control of the quality of work treatment. None of these applications suggested that plasma ion nitriding would be a solution to the problems solved by the present invention.
Plasma ion nitriding is based on plasma discharge physics and operates by exposing a negatively charged metal work piece surface to positively charged nitrogen ions. Under vacuum in a sealed vessel, an electrical potential is applied to the system, wherein the vessel becomes the positively charged anode (electron receptor) and the work piece forms the negatively charged cathode (cation receptor). High voltage energy is used to strip electrons from nitrogen bearing gas molecules introduced into the vessel, forming a plasma, where the nitrogen ions are accelerated toward the work piece. The impact of the nitrogen ions on the surface of the work piece generates heat energy from the conversion of kinetic energy to potential energy. As the nitrogen ions impact the work piece surface, iron atoms predominantly are sputtered off at the point of impact to combine with other nitrogen ions forming iron nitride ions above the work piece surface in the glow discharge "seam". These iron nitride ions then impact and deposit on the heated work piece surface and diffuse into the subsurface molecular boundaries, creating an exposed surface layer and a distinct subsurface structure offering many of the desired characteristics for press plates as noted above, such as high hardness without brittleness, an unmarred surface finish, and a determined case depth.
OBJECTS OF THE INVENTION
Accordingly, it is an object of this invention to provide a hardened flat work piece, such as a press plate, for the economical production of wear resistant decorative laminates.
It is a principle object of this invention to provide a plasma ion nitrided press plate which provides significantly greater wear life in the production of decorative laminates.
It is a further object of this invention to provide a press plate for the economical production of wear resistant decorative laminates having a high-quality microfinish of greatly extended press plate life
It is also an object of this invention to provide a press plate free of objectionable warpage for the economical production of wear resistant decorative laminates.
It is another object of this invention to provide a method for producing a plasma ion nitrided press plate offering significantly greater wear life in the production of decorative laminates.
It is yet another object of this invention to provide the processing parameters for producing a plasma ion nitrided press plate for the economical production of wear resistant decorative laminates.
It is a still further object of this invention to provide a method for using a press plate hardened by plasma ion nitriding processes for the economical production of wear resistant decorative laminates.
Other objects, advantages, and features of the present invention will be in part apparent and in part explained by reference to the following detailed description and appended claims, and upon reference to the accompanying drawings.
SUMMARY OF THE INVENTION
In accordance with this invention, a process and apparatus were developed to harden press plates by the use of plasma ion nitriding techniques, wherein to the applicants' knowledge such large work piece plasma ion nitriding has never before been attempted or successfully achieved.
The application of the plasma ion nitriding process to large work pieces having very exacting final microfinish requirements, as disclosed by the present invention, is an advance due to the complicated relationships between parameter settings and expected results. These relationships include the work piece geometry, material surface and subsurface structure and desired results, process temperatures, pressures, and duration of heat-up time, thermal loading, radiant and convective heat energy effects, cooling system requirements, and gas mixture composition.
Accordingly, testing and analysis was coordinated to determine the proper functional parameters, the inter-relationship of functional parameters, and the allowable variance within each functional parameter or group of functional parameters to produce the desirable product specifications. To this end, a general geometry formula was identified which describes the press plate surface area to thickness ratios for which the required parameters will apply.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of this invention, one should refer to the embodiment illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention.
In the drawings:
FIG. 1 is a simplified perspective view of the nitriding vessel related to the invention, with the press plate fixture installed;
FIG. 2 is a front elevation view of the clamp of the press plate fixture along the view 2--2 shown in FIG. 1;
FIG. 3 is a side elevation view of the clamp of the press plate fixture along the view 3--3 shown in FIG.
FIG. 4 is a chart depicting the temperature profile over time of the process according to the invention; and
FIG. 5 is a elevation side view of a representational press and pack, utilizing the press plates according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the figures, wherein like reference characters designate like or corresponding parts throughout the views, FIG. 1 illustrates the overall configuration of the reaction vessel 10 and the stainless steel press plate fixture 100 as installed. The reaction vessel 10 related to the present invention is that used by the MPT GmbH PLASMA-TRIDING® process employing THERMION® processing and control equipment.
For purposes of simplified presentation, however, the vessel 10 includes a cylindrical outer wall 12, a cylindrical inner wall 13, and a cylindrical heat deflection shield 14, all located concentrically within the outer wall 12. It should be understood that other vessel geometries (i.e., a horizontal rectangular chamber), and control system configurations are also capable of producing the desired results, and that vessel size is important only to the extent of the restriction it places on the press plate dimensions that can be processed. The outer wall 12, the inner wall 13, and the heat deflection shield 14, as will be discussed below, act as the anode during the nitriding process. Between the outer wall 12 and the inner wall 13 is an annular cooling water chamber 16, wherein cooling water 18 is passed through to assist in maintaining the critical processing temperatures, as will be discussed below. The outer wall 12, the inner wall 13, and the heat deflection shield 14 share a viewing port 20 to allow for visual "glow checks" of the press plate during the nitriding process The inner wall 13 and the heat deflection shield 14 are preferably formed from stainless steel or an alloy to prevent extraneous metals from becoming disassociated and contaminating the gaseous mixture treating the press plate.
The vessel 10 is further provided with a water supply 22 to provide the annular cooling water chamber 16 with a continuous regular source of cooling water to avoid excessive temperatures in the vessel 10, which if unchecked can contribute to excessive press plate temperatures and subsequent objectionable press plate warpage. The vessel 10 is further provided with a vacuum pump 24, a gas supply containing nitrogen 26, a high voltage source 28, and a controller unit 30. The high voltage source 28 provides a positive charged DC supply to the vessel 10 structure and a negative charged DC supply to the hanging fixture-press plate assembly 100 contained within. The controller unit 30 corresponds to the THERMION® control equipment used in the MPT GmbH PLASMA-TRIDING® process.
The fixture 100 as shown in FIG. 1 is comprised of base members 102, support rods 104, cross member 106, and support arms 108. As seen in FIGS. 1, 2, and 3, the press plate 50 is suspended from the support arms 108 with clamps 110 and hanging rods 112. The press plates 50 must be separated by a distance sufficient to avoid interaction of the glow discharge plasma boundary of one press plate with that of the adjacent press plates. Further, this distance must minimize heat transfer from one press plate to the adjacent press plate to thereby avoid thermally induced distortions. Initial testing indicates that this distance is preferably about 8 inches (20.3 centimeters) or more, although other press plate dimensions may require different spacing criteria.
As better viewed in FIGS. 2 and 3, the clamps 110 are simple clevis devices supported by hanging rods 112. At the opposite end, a notch 116 is sized to slidingly accept the thickness of the press plate 50, which is usually about one eighth of an inch. Once the press plate 50 is inserted into notch 116, the clamp 110 is affixed to the press plate 50 by tightening fasteners 118. The clamp 110 is then attached to the support arms 108 through the hanging rods 112. To reduce the amount of thermally absorbent material about the edge of the press plate 50, the clamp 110 is tapered inwardly toward the notch 116 by cutting or milling the projecting corners 120 away (shown in phantom). Accordingly, the amount of mass which can absorb heat from the press plate 50 is minimized, which has been found to be a critical aspect of the present invention. It is very important that the press plate 50 be exposed to as little temperature gradations as possible to avoid warping. Thus, by clamping each of the press plates 50 to the clamps 110, attached to the support arms 108 coupled to the crossmember 106, the press plate 50 can be suspended in the vessel without substantial thermal interaction with the fixture 100.
The preferred method of nitriding is according to the MPT GmbH PLASMA-TRIDING® process using THERMION® processing and control equipment. This process utilizes electronic control equipment with arc discharge suppression control to minimize plate defects. Special processing conditions must be used for the press plates according to the present invention and are addressed below. The energy of the impact of the nitrogen ions, if uncontrolled, often generates heat energy and work piece temperatures capable of destroying the utility of large work pieces, such as press plates. This damage is evidenced by the deleterious effects of objectionable warping, buckling, and blemishes to the microfinish including imperfections such as arc trails ("spider marks" and "pimples"), localized meltdown ("comet tails"), clamp mark "halos", and other damage to the work piece. Accordingly, the commercial use of plasma nitriding for the hardening of large work pieces with exceptionally high surface to volume ratios, such as press plates, has heretofore not been considered viable
The processing of the press plates to be treated in accordance with this invention begins with a pre-nitriding two-step cleaning procedure to remove water soluble, oil soluble, and insoluble residues from the work piece. These can often be attributed to the cause of "arc trails". The failure to remove any such residue can result in especially intense arc discharges during the initial nitriding process, which can damage the microfinish of the press plate 50.
The residues on the surface of a press plate typically are present in minute quantities resulting from earlier processing of the plate 50. Freshly refinished polished plates, although appearing visually clean, will still have residual polishing or buffing compounds (commonly called rouges) deposited on their surface. Rouges typically are composed of a very fine abrasive material such as alumina combined with a waxy material (solid at room temperature which melts when applied to a warm plate during processing) or the abrasive material is combined with fatty acid "greases" in a water based emulsion (liquid at room temperature). Freshly refinished textured plates, using shot-blasting techniques, usually have remnants of very fine dust, resulting from some breakage of the shot used in the blasting process, adhering to the plates' surface because of static charges. Oily fingerprints, and other extraneous oil and grease spots on either type of plate, but particularly the textured plates, are common types of contamination as well. Additionally, press plates, particularly those not freshly refinished, will usually have deposited on their surface trace amounts of a mold release agent which can be applied directly to the plate (external release agent), but is most often incorporated into the liquid surface resin itself (internal release agent). These release agents promote easy separation of the plates from the laminates after curing in the pressing operation. The most widely used release agents are fatty acid based, including common tallow acid soap (stearate/palmitate mixtures), zinc stearate powder (applied directly to the plate) and a variety of commercially available products well known to those versed in the art.
The two-step cleaning procedure involves first thoroughly cleaning a plate with deionized water. After allowing it to dry, the plate is then thoroughly washed with a chlorinated hydrocarbon solvent, of which 1,1,1-trichloroethane is the preferred solvent. In this manner, both water soluble and oil soluble materials are dissolved and removed from the plate, as are remaining insoluble particles by means of the physical washing action.
The press plate 50 is then mounted in the fixture 100, as described above. As an important aspect of this invention, the loading and fixturing of the press plates has a direct impact on the selection of process parameters. The thermal loading of the press plates generates radiant and convective heat energy, which in turn necessitates the proper modulation of the press plate temperature The dissipation of this heat energy generated is controlled through the modulation of the input voltage, the flow rate of the cooling water chamber 16, and the spacing of the press plates 50 within the vessel 10.
A temperature sensing means, preferably a thermocouple 52 as shown in FIG. 1, located within the loaded vessel 10 is a primary factor in modulating the heat energy generated within the vessel 10. The thermocouple 52 placement at the edge of a centrally located press plate mounted to the fixture 100 has been found to be an ideal location for this geometry. Because of plasma physics and because of the ion bombardment on all surfaces of an "edge" or a "corner", this edge or corner will have the tendency to heat-up faster than the center of the plate 50. Therefore, the temperature of the outside surface of the press plate 50 will increase somewhat more quickly than the center of the plate. The thermocouple 52 at the edge thus offers better control over the heat-up rate and a more consistent temperature profile through the cross section of the plate 50. Other locations for the thermocouple were found to lead to erroneous temperature data, which tends to confound controller 30 input and can lead to distortion and an uneven case hardness.
The vessel 10, after loading, is then sealed and air is evacuated by vacuum pump 24 to form a vacuum therein The vessel 10 is then filled with a nitrogen-containing gas, such as gaseous ammonia, at a pressure of 0.04 to 0.12 psi (3 to 8 millibar) through nitrogen gas supply 26. Other gaseous mixtures containing nitrogen atoms may also be advantageously employed For example, in the case of press plates having high chromium content, a nitrogen and hydrogen mixture would be recommended, as the hydrogen promotes the formation of chromium nitride. Furthermore, this gaseous mixture can be more easily controlled for purity and dryness. However, excessive concentrations of hydrogen in the presence of a base material having low or no chromium content can contribute to hydrogen embrittlement. The use of carbon-bearing gases, such as methane, in the gas mixture is not recommended due to the deleterious effects of carburization.
A voltage is then applied to the system through the high voltage source 28 and a glow discharge forms about the press plate as the process enters the sputtering phase. Arc discharges generated within the glow discharge are directed toward any remaining residue and deposits on the work piece and serves as a final cleaning process. Any such residue or deposits are thus vaporized and removed from the work piece In this phase, the work piece itself has only increased moderately in temperature to about 200° F. This phase, corresponding to Region I of FIG. 4, continues until all deposits are removed and the arc discharges diminish.
The voltage is then steadily increased, as shown in Region II of FIG. 4, to accelerate the ion bombardment and begin the temperature rise to temperatures optimum for the nitriding phase. During this phase, the human eye is used to conduct a "glow check" operation. As the operation requires the regulation of the rate of increased power input, a "glow check" through the port 20 of the vessel 10 to observe the uniformity and color of the glow discharge is made. As the press plate 50 begins to glow about its outside surface, it is important to allow the center of the press plate 50 to reach the same temperature without a large and potentially damaging temperature disparity between the edge and center press plate 50 portions. Thus, when the outer edges of the pres plate 50 glow to reveal the appropriate temperature as evidenced by the proper glow color, the voltage intensity is maintained for about one hour, as depicted by Region III of FIG. 4, allowing the remaining portions of the press plate to reach an even temperature distribution. It has been determined that this glow temperature should be maintained at about 70 to 80 percent of the maximum nitriding temperature
Also, the press plate 50 should be inspected for 'hot spots" during this period. As the glow color is directly proportional to the surface temperature of the press plate, any variations in color would indicate a variation in temperature, which should be avoided. As noted above, the temperature can be controlled via voltage input and the water flow rate through the water chamber 16.
Once the work piece temperature is stabilized, the voltage is increased, as shown in Region IV of FIG. 4, to 100 percent of that required to obtain the maximum desired temperature, and the automatic processing system is allowed to control the remaining processing, depicted as Region V of FIG. 4. During the cool-down phase, shown as Region VI of FIG. 4, the controller 30 is also used, while the vessel 10 is kept under vacuum to avoid oxidation on the press plate 50. The water flow in the cooling chamber 16 should also be maintained.
During the processing phase of Regions I, II, III, IV, and V, additional nitrogen-containing gas must be added to the vessel 10 to replenish that which is ionized and deposited on the work piece or lost to the vacuum system. Thus, additional gas is constantly introduced at very slow flow rates to maintain the vessel partial pressure. This flow rate has been determined to be dependant on the cycle time and modified as necessary.
Based on empirical test results, the processing parameters found most favorable for the geometry of press plates are provided in Table A.
TABLE A______________________________________Parameter Set Region of FIG. 4______________________________________Maximum temperature: 750-850° F. (400-450° C.)Pressure: 0.04-0.12 psi (3.0-8.0 mb)Heat-up time: 12-20 hours Regions I & IIProcessing time: 20-48 hours Regions III, IV & VCooling time: 2-8 hours Region VI______________________________________
The selection of a parameter "set" depends on the desired hardness and case depth of the work piece. This hardness is manifest in two portions of the work piece; the compound layer and the diffusion zone. The compound layer is formed on the exposed surface and is comprised essentially of ferrous nitride compounds and, in the case of stainless steel, a percentage of chromium nitride compounds. The diffusion zone, found beneath the compound layer, is hardened to a slightly lesser degree due to the propagation of nitrogen ions and ferrous nitride ions into the grain boundaries to form a decreasing concentration of nitride compounds. Thus, the compound layer and diffusion zone to be hardened, defining the hardened case depth, is related to the material and the geometry of the press plate 50. Note that the voltage potential (and corresponding temperature) and processing time are inversely related; if the processing time of Region V is extended, the overall maximum temperature can be reduced.
The geometry formula developed in conjunction with the present invention examines the surface area to thickness ratio. The relationship of surface area in square feet to plate thickness in inches should be 150 square feet/inch to 2800 square feet/inch (5.5 square meters/centimeter to 102.5 square meters/centimeter). These values correspond to press plates having nominal dimensions of 3 feet by 7 feet (0.9 meter by 2.1 meters) having a thickness of one quarter inch (0.64 centimeter) and press plates having nominal dimensions of 5 feet by 16 feet (1.5 meters by 4.9 meters) having a thickness of one sixteenth inch (0.16 centimeter), respectively. Combinations of length, width, and thickness within these numeric ratios should be within the indicated parameters of the instant invention.
It has been determined that the preferred compound layer depth is between 0.0001 and 0.0004 inch (0.0025 and 0.0102 millimeter). The overall preferred case depth, including the compound layer and diffusion zone, is between 0.001 and 0.004 inch (0.025 and 0.102 millimeter). However, other compound layer and diffusion zone thicknesses can be obtained depending on the specific requirements of the end product.
Preferably, the vessel 10 is vented and the press plate 50 is removed from the unsealed vessel 10 only after it reaches room temperature. However, the press plate 50 can be removed when its temperature cools to about 200° F. (100° C.). Although removing the press plate 50 prior to its reaching room temperature reduces the processing time by six hours for productivity purposes, it also creates some oxidation on the plate surface caused by room temperature air coming into contact with the warm press plate 50 when the vessel 10 is opened. This layer can be rubbed off as necessary. If the work piece is allowed to reach room temperature, i.e., a significantly extended cool-down period opposed to the shorter 2 to 8 hour period noted above, it has been found that a shinier finish with less oxidation may be obtained. The oxidation caused by the room temperature air entering the vessel 10 while the press plate 50 is above room temperature may be avoided by the introduction of nitrogen or an inert gas into the vessel without voltage input to accelerate the final phase of the cooling process.
However, it must be emphasized that accelerating the cool-down rate with the plate still at an elevated temperature (between the processing temperature and above about 200° F. (100° C.)) can result in stress relief of the plate accompanied by its deformation The cooler air entering the vessel 10 does not contact the press plate 50 uniformly contributing to sharp thermal gradients and accompanying stress relief Decreasing the cooling chamber 16 temperature, increasing the cooling chamber 16 flow rate, venting the vessel 10 to atmosphere (which will also cause severe oxidation of the plate surface), or introducing an inert "cooling gas" are all mechanisms that at elevated temperatures can promote such stress relief and deformation. The higher the temperature at which such accelerated cooling is attempted, the more serious the plate deformation and possibly oxidation will be.
To appreciate the advantages of the present invention, "conventional" non-hardened polished press plates used to produce grit-free decorative laminates must be refinished on average about every 200 cycles due to normal handling damage. Plates used to press more critical colors, such as dark or black solid color laminates, may be refinished or down-graded after as few as 30 to 50 cycles because of handling damage so as to maintain acceptable laminate finish quality.
In addition to the optical distortion evaluations used to determine the quality of the press plate surface finish, the surface finish of the laminate manufactured by the press plate can also be used to determine the press plate surface finish quality. NEMA 60 degree gloss measurements are commonly used to characterize laminate finishes. As the marketplace has become much more critical in recent years, haze-free high gloss surfaces are now demanded. As such, the scale shown in Table B is generally accepted in the industry.
TABLE B______________________________________Laminate Gloss Finish Quality______________________________________≧100 excellent95-99 good-very good90-94 marginal<90 unacceptable______________________________________
To measure the improvement in performance with nitrided press plates, trial runs on black glossy finish "proof" laminates, the severest test of plate finish quality, were compiled using full scale 4 feet by 10 feet (1.22 by 3.05 meters) polished press plates as shown in Table C. The grit used was aluminum oxide incorporated within a liquid melamine surface resin.
TABLE C______________________________________Number of Press Runs to ProduceCommercially Unacceptable MicroscratchingSurface Grit Standard Hard Chrome Plasma ionSize/Loading 410 SS Plated 410 SS Nitrided 410 SS______________________________________5% 3 μm 1 >81* NA1% 6 μm 1 8 2341% 6 μmand 1 NA >100**0.5% 15 μm0.8% 6 μmand 1 1 NA1.6% 25 μm9% 30 μm 1 NA >15 and <33______________________________________ *NEMA 60 degrees gloss 99.1 at 8 pressings NEMA 60 degrees gloss 95.8 at 63 pressings **NEMA 60 degree gloss 98.5 at 1 pressing with Dorigon gloss 43.5 and Haz Index 1.20 NEMA 60 degree gloss 97.1 at 100 pressings with Dorigon gloss 60.7 and Haze Index 0.93
For example, the laminate produced from the 3 μm grit as 5 percent by weight of liquid resin in trial runs using a chromed polished plate suggests that deterioration in the plate and laminate microfinish occurred from microscratching. Note that the NEMA gloss value for this trial fell from a very good, nearly excellent level of 99.1 to only a marginally acceptable level of 95.8, suggesting significant plate wear occurred over a period of 55 pressings Additional pressings, at least up to 81 pressings, continued this trend toward decreasing acceptability.
Conversely, after 100 pressings with the nitrided polished press plate using much more aggressive 6 μm and 15 μm grit formulations, the gloss remained constant in the good to very good category. As Dorigon gloss is a very good indication of a glossy laminate's finish quality, it is therefore a key index of the quality of the polished plate that Dorigon gloss values of 40 or greater, and haze indices of less than 1.5 are indicative of an excellent quality, highly reflective laminate and plate microfinish. Note that even with this relatively aggressive grit formulation, the laminate produced after 100 pressings exhibited no deterioration in Dorigon gloss. Surprisingly, there appeared to be very significant improvement in reflectivity to a level seldom achieved with any polished plate. It should be noted that the nitrided press plate exposed to 1 percent by weight of liquid resin 6 micron grit was rebuffed after 234 cycles and shown to produce acceptable laminate quality for at least another 103 cycles. Also, although the 9 percent by weight of liquid resin 30 micron grit offers only limited press plate durability compared to smaller grit concentrations and sizes, it nevertheless indicates that the use of such aggressive grit formulations is possible if relatively frequent plate refinishing is acceptable (about the same frequency as a "dark" quality conventional polished plate).
It was also observed during these trials that the nitrided plates were easier to release from the laminate after the curing and pressure process than conventional polished press plates. As noted above, press plates are used with composites of laminate resin impregnated treated papers placed therebetween, facing opposite directions, as shown in FIG. 5. Multiple layers of press plates 50, laminate material 200, separator sheets 201, and cushions 203 placed on carrier trays or "pans" 207 to form "packs" 202, which are then loaded into a press 204 between heating/cooling platens 205 for temperature and pressure treatment consolidation and curing. Note that as the clearance for material movement into the press 204 between the heating/cooling platens 205 is limited by the press opening or "daylight" 206, i.e., the space between two platens when the press 204 is fully open it is apparent from FIG. 5 that excess plate warpage of the first type can interfere with the ability to move the pack 202 into the press 204.
After the cure period of about 45 to 90 minutes typically at temperatures of 260° to 300° F. (125° to 150° C.) and subsequent cooling, varying levels of physical effort by the press operators are necessary to disassemble the packs 202 into its press plate and finished laminate constituent parts. For example, the releasability of textured plates has been found to be generally less than that of polished plates. Further, "picking", or small deposits of resin and fibrous material remaining on the press plate 50 can occur, with transfer to and contamination of the surface of subsequently pressed laminate from the same press plate 50. In the worst case, the entire laminate sheet can become physically bonded to the press plate 50, causing serious refinishing problems.
These problems are often reduced by the use of release agents on the plate surface, most often incorporated into the resin, or by the use of chrome plated plates. During the aforementioned press plate trials, it was surprisingly found that the nitrided hardened press plates released considerably easier than conventional polished steel plates. It is theorized that the deposition of the compound layer fills in (and seals) the surface microtexture, creating an even smoother microfinish then otherwise possible, reducing its tendency to adhere to the laminate surface in contact with it. Thus, in the event that the desired quantity of release agent is inadvertently omitted or the difficulties of chrome-plating noted above are to be avoided, the use of plasma ion nitrided press plates is expected to offer greater releasability.
Moreover, the invention herein disclosed is not limited to high pressure decorative laminate, but can also be beneficially applied to low pressure decorative laminates, such as those containing a particleboard or medium density fiberboard substrate rather than a plurality of phenolic resin impregnated cellulosic core sheets of the high pressure decorative laminate (surfaced with a print or solid color sheet and optionally, an overlay sheet). In contrast to the cure period of about 45 to 90 minutes at pressures ranging from 1000 to 1600 psi (6.9 to 11.0 N/mm 2 ) for pressing high pressure laminate, low pressure laminates have cycle times of about 1 minute at pressures of 200 to 300 psi (1.4 to 2.1 N/mm 2 ). The use of aggressive grit formulations or other hard materials in the laminate at the rapid cycle rates used to produce low pressure laminates will quickly deteriorate the pres plates of such applications. Therefore, the utility of the present invention should be applicable to a wide range of decorative laminate products.
Although these press trials of Table C were limited to nitrided polished plates of 410 stainless steel, where the resulting plate hardness was found to increase from 38-45 HRc to 60≧70+ HRc, although hardnesses of over 65 HRc are preferred, potential application for nitride hardened press plates is much broader, as are the grades of stainless steel that can be so treated. The use of plasma ion nitrided textured press plates is expected to display even greater durability in terms of grit related microscratching, wear, and gloss deterioration in comparison to conventional textured steel plates.
Further, while 410 stainless steel has historically been the material of choice, plasma ion nitriding of 630 and 304 alloy stainless steel press plates also offers benefits.
630 stainless steel is similar to 410 stainless steel, but has about half the carbon content (0.05-0.08% versus 0.15%) while maintaining equivalent hardness (42-45 HRc) by means of a special precipitation hardening process. The lower carbon content is preferred for chemical etching of textured plates. A trial with a full size (4 feet by 10 feet (1.22 by 3.05 meters)) textured plate according to the present invention increased the case hardness to 67-70 HRc from 42-45 HRc.
A limited 304 stainless steel trial was also conducted according to the present invention. 304 stainless steel is an annealed "bulk unhardenable" austenitic stainless steel with high chromium content (18.0-20.0 versus 1.5-13.5) and nickel content (8.0-10.5 versus 0.75) compared to 410 stainless steel. Although 304 stainless steel press plates, including high gloss mirror finish plates, are sold commercially and used as press plates due to their lower cost, they are also very susceptible to scratching and other plate handling damage due to their softness. 304 stainless steel is so soft that it bearly registers on the Rockwell C hardness scale (comparative hardness on the "softer" Brinell scale are 140 for the 304 alloy and 390 for the 410 alloy). The case hardness obtained after employing the present invention was 73 HRc, compared to an initial hardness of only 29 HRc. Plasma ion nitriding of 304 stainless steel is thus expected to largely resolve the former problems of 304 stainless steel. Other alternative applications may also exist, i.e., nitrided chrome plated plates, to further increase hardness
It will be understood that the details, materials and arrangements of parts of specific embodiments have been described and illustrated to explain the nature of the invention. Changes may be made by those skilled in the art without departing from the invention as expressed in the appended claims.
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A press plate hardened by the use of plasma ion nitriding techniques produces wear resistant decorative laminate containing hard abrasive particles while improving associated press plate useful life. The press plate has exacting final microfinish requirements made possible due to the determination of interdependencies between parameter settings and expected results. These interdependencies include the work piece geometry, surface and subsurface structure and desired results, process temperatures, pressures, and rate of heat-up and duration of heat-up time, thermal loading, reflective radiation and heat effects, cooling systems, and gas mixture composition.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The disclosure of Japanese Patent Application No. 2007-171665 filed on Jun. 29, 2007 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a technique which enhances strength and visibility of a miniaturized display device used in a mobile phone or the like.
2. Description of the Related Art
With respect to a liquid crystal display device, there has been a strong demand for the reduction of a thickness of a liquid crystal display panel along with a demand for the reduction of a profile size of a set while maintaining a screen at a fixed size. To decrease the thickness of the liquid crystal display panel, after manufacturing the liquid crystal display panel, an outer side of the liquid crystal display panel is polished to decrease the thickness of the liquid crystal display panel.
The liquid crystal display device is constituted of a TFT substrate which forms pixel electrodes, TFTs and the like thereon or a color filter substrate which forms color filters thereon. A glass substrate which is served for forming the TFT substrate and the color filter substrate has a thickness thereof standardized to 0.5 mm or to 0.7 mm. It is difficult to acquire such standardized glass substrate from a market. Further, an extremely thin glass substrate gives rise to drawbacks on mechanical strength, deflection or the like in manufacturing steps thereof thus lowering a manufacturing yield rate. As a result, after forming the liquid crystal display panel using the standardized glass substrate, an outer surface of the liquid crystal display panel is polished to decrease the thickness of the liquid crystal display panel.
The reduction of the thickness of the liquid crystal display panel gives rise to a drawback on mechanical strength. That is, there exists a possibility that the liquid crystal display panel is broken when mechanical pressure is applied to a display screen of the liquid crystal display panel. To prevent such breaking of the liquid crystal display panel, as shown in FIG. 10 , in assembling the liquid crystal display panel in a set such as a mobile phone, a front window (hereinafter referred to as face plate) is mounted on a screen side of the liquid crystal display panel. The face plate is usually formed larger than the color filter substrate.
To prevent the application of a force to the liquid crystal display panel when an external force is applied to the face plate, the face plate is arranged in a spaced-apart manner from the liquid crystal display panel. However, the constitution shown in FIG. 10 gives rise to a drawback that display quality is deteriorated as described later. Japanese Patent Laid-Open Hei11-174417 (patent document 1) discloses a technique which copes with the drawback attributed to the structure shown in FIG. 10 , for example.
SUMMARY OF THE INVENTION
The related art shown in FIG. 10 gives rise to a drawback that an image appears as a duplicate image. FIG. 10 is a view explaining the drawback by taking a reflective liquid crystal display panel as an example. In FIG. 10 , an incident external light L passes a face plate, is reflected on the liquid crystal display panel, passes the face plate again, and enters human eyes. Here, although the external light L is refracted on the face plate, the refraction is ignored in FIG. 10 .
A portion of light reflected on a screen P 1 of the liquid crystal display panel is reflected on a lower surface Q 1 of the face plate, is incident on a screen P 2 of the liquid crystal display panel, and is reflected on the screen P 2 of the liquid crystal display panel. When a viewer recognizes light reflected on the screen P 2 with his/her eyes, a phenomenon that an image appears as a duplicate image occurs. Although the explanation has been made by taking the reflective liquid crystal display panel as an example in FIG. 10 , the same goes for a transmissive liquid crystal display panel. That is, in the transmissive liquid crystal display panel, when light passes the liquid crystal display panel at an angle equal to an angle of reflection light on a screen P 1 each of the liquid crystal display panel, light is reflected on a lower surface Q 1 of a face plate, and traces a path in the same manner as a path of the reflective liquid crystal display panel. The phenomenon which makes the image appear as a duplicate image deteriorates image quality.
In the technique described in patent document 1, for example, which copes with such a drawback, an adhesive resilient body is arranged between the face plate and the liquid crystal display panel. The adhesive resilient body protects the liquid crystal display panel from an external force. Further, by setting reflectance of the adhesive resilient body to a value close to reflectance of the face plate, the reflection on an interface with the face plate can be suppressed. However, the technique disclosed in patent document 1 requires the uniform adhesion of the face plate eliminating the presence of bubbles or the like between the face plate and the adhesive resilient body and hence, it is extremely difficult to apply the technique to the mass production of the liquid crystal display panels. Further, there arises a drawback in selecting a material which can approximate the reflectance of the adhesive resilient body to the reflectance of the face plate. In addition to these drawbacks, since the adhesive resilient body requires considerable thickness, the technique disclosed in patent document 1 cannot completely overcome the drawback that the image appears as the duplicate image.
The present invention has been made to overcome the above-mentioned drawbacks of the related art, and the specific constitutions of the present invention are as follows.
(1) The present invention is directed to a liquid crystal display device including a liquid crystal display panel which has a TFT substrate on which pixel electrodes and TFTs for controlling signals to the pixel electrodes are arranged in a matrix array and a color filter substrate on which color filters corresponding to the pixel electrodes are formed, wherein an upper polarizer is adhered to the color filter substrate, a face plate made of glass is adhered to the upper polarizer, and the upper polarizer and the face plate are adhered to each other using a ultraviolet curing resin.
(2) The liquid crystal display device described in the constitution (1) is characterized in that the ultraviolet curing resin is a liquid containing an acrylic resin at the time of initially adhering the face plate and the upper polarizer adhered to the liquid crystal display panel.
(3) The liquid crystal display device described in the constitution (1) is characterized in that the ultraviolet curing resin is a liquid containing an acrylic oligomer at the time of initially adhering the face plate and the upper polarizer adhered to the liquid crystal display panel.
(4) The present invention is also directed to a liquid crystal display device including a liquid crystal display panel which has a TFT substrate on which pixel electrodes and TFTs for controlling signals to the pixel electrodes are arranged in a matrix array and a color filter substrate on which color filters corresponding to the pixel electrodes are formed, wherein an upper polarizer is adhered to the color filter substrate, a face plate made of glass is adhered to the upper polarizer, and a corner portion of the face plate is chamfered with a cutting size of 0.3 mm or more.
(5) The liquid crystal display device described in the constitution (4) is characterized in that the corner portion of the face plate is chamfered with a cutting size of 0.5 mm or more.
(6) The liquid crystal display device described in the constitution (4) is characterized in that a side portion of the face plate is chamfered with a cutting size of 0.05 mm or more.
(7) The liquid crystal display device described in the constitution (4) is characterized in that the side portion of the face plate is chamfered with a cutting size of 0.15 mm or more.
(8) The present invention is also directed to a liquid crystal display device including a liquid crystal display panel which has a TFT substrate on which pixel electrodes and TFTs for controlling signals to the pixel electrodes are arranged in a matrix array and a color filter substrate on which color filters corresponding to the pixel electrodes are formed, wherein an upper polarizer is adhered to the color filter substrate, a face plate made of glass is adhered to the upper polarizer, and a corner portion of the face plate is rounded with a corner radius R of 0.3 mm or more.
(9) The liquid crystal display device described in the constitution (8) is characterized in that the corner portion of the face plate is rounded with a corner radius R of 0.5 mm or more.
(10) The liquid crystal display device described in the constitution (8) is characterized in that a side portion of the face plate is chamfered with a cutting size of 0.05 mm or more.
(11) The liquid crystal display device described in the constitution (8) is characterized in that the side portion of the face plate is chamfered with a cutting size of 0.15 mm or more.
(12) The present invention is also directed to a liquid crystal display device including a liquid crystal display panel which has a TFT substrate on which pixel electrodes and TFTs for controlling signals to the pixel electrodes are arranged in a matrix array and a color filter substrate on which color filters corresponding to the pixel electrodes are formed, wherein an upper polarizer is adhered to the color filter substrate, a face plate made of glass is adhered to the upper polarizer, and the face plate has a profile smaller than a profile of the upper polarizer.
(13) The liquid crystal display device described in the constitution (12) is characterized in that the upper polarizer and the face plate have an approximately rectangular shape, and the face plate is shorter than the upper polarizer by 0.5 mm or more with respect to a short-axis length and a long-axis length.
(14) The liquid crystal display device described in the constitution (12) is characterized in that the corner portion of the face plate is chamfered with a cutting size of 0.3 mm or more.
(15) The liquid crystal display device described in the constitution (12) is characterized in that the corner portion of the face plate is rounded with a corner radius R of 0.3 mm or more.
According to the present invention, the face plate made of glass can be adhered to the liquid crystal display panel and hence, the deterioration of image quality attributed to the interface reflection between the face plate and the liquid crystal display panel can be largely reduced. That is, in initially adhering the face plate to the liquid crystal display panel, that is, before the adhesive material is cured by ultraviolet rays, the adhesive material is in a liquid state and hence, it is possible to uniformly adhere the face plate to the liquid crystal display panel.
Further, according to the present invention, the glass face plate can be used and hence, the face plate exhibits high surface hardness whereby the deterioration of image quality attributed to flaws on the face plate or the like can be largely reduced. Further, by adhering the glass face plate to the liquid crystal display panel using the adhesive material, the thickness of the whole liquid crystal display device can be set smaller than the whole thickness of the conventional liquid crystal display device.
Since proper chamfered portion or rounded portion is formed on a corner portion of the face plate according to the present invention and hence, the strength of the face plate can be increased and, at the same time, a phenomenon that the face plate is peeled off at the corner portion can be prevented.
In addition to the above-mentioned advantageous effects, chamfering is applied to all sides of the face plate according to the present invention and hence, strength of the face plate can be enhanced and, at the same time, white dot defect attributed to burrs on the side portions of the face plate can be prevented.
Further, the face plate according to the present invention is smaller than the upper polarizer in size and hence, the generation of bubbles at the time of adhering the face plate to the upper polarizer can be suppressed thus allowing the face plate to be uniformly adhered to the liquid crystal display panel.
According to the present invention, by adopting the above-mentioned constitutions, the direct adhesion of the glass face plate to the liquid crystal display panel which has been impossible conventionally can be realized.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a liquid crystal display device to which the present invention is applied;
FIG. 2 is a cross-sectional view taken along a line A-A in FIG. 1 ;
FIG. 3 is a view showing a state that a face plate is mounted on a liquid crystal display panel;
FIG. 4A to FIG. 4C are views showing a profile of the face plate of an embodiment 1;
FIG. 5 is a flowchart showing manufacturing steps of the face plate;
FIG. 6 is a schematic view showing a profile-polishing machine of the face plate shown in FIG. 4 ;
FIG. 7 is a schematic view showing a state that the face plate is wrapped;
FIG. 8A to FIG. 8C are views showing a profile of a face plate of an embodiment 2;
FIG. 9A to FIG. 9C are schematic views showing a profile-polishing machine of the face plate shown in FIG. 8 ; and
FIG. 10 is a view showing the relationship between a face plate and a liquid crystal display panel of the related art.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is explained in detail in conjunction with embodiments.
Embodiment 1
FIG. 1 is an exploded perspective view showing a liquid crystal display device of an embodiment 1 according to the present invention. FIG. 2 is an exploded cross-sectional view taken along a line A-A in FIG. 1 . In FIG. 1 , a liquid crystal display panel is constituted of a TFT substrate 11 and a color filter substrate 12 . Pixel electrodes are formed on the TFT substrate 11 in a matrix array. TFTs (Thin Film Transistors) for changing over a signal supplied to respective pixel electrodes are also formed on the TFT substrate 11 . The color filter substrate 12 which forms color filters thereon is arranged to face the TFT substrate 11 in an opposed manner.
Respective thicknesses of glass substrates used in the manufacture of the TFT substrate 11 and the color filter substrate 12 are set to 0.5 mm. After completion of manufacturing of the liquid crystal display panel by filling and sealing liquid crystal between the substrates, outer sides of the liquid crystal display panel are polished so as to reduce a thickness of the whole liquid crystal display panel. In this embodiment, a thickness of the liquid crystal display panel after polishing is approximately 0.6 mm. That is, the thicknesses of the respective glass substrates are decreased by 0.2 mm by polishing.
The TFT substrate 11 is larger than the color filter substrate 12 in size, and a drive IC 13 and a flexible printed circuit board 15 are mounted on a portion of the TFT substrate 11 where the color filter substrate 12 does not overlap with the TFT substrate 11 . The liquid crystal display panel is housed in a resin mold 16 so that the liquid crystal display panel is mechanically protected. Although a portion of the liquid crystal display panel where the TFT substrate 11 and the color filter substrate 12 overlap with each other is mechanically strong, a portion of the liquid crystal display panel which is constituted of only the TFT substrate 11 is mechanically weak. Accordingly, the liquid crystal display panel adopts the mold 16 structure for preventing an impact from being applied to such a mechanically weak portion.
A backlight is arranged below the mold 16 . In FIG. 1 , among components of the backlight, only a light guide plate 17 is shown. The flexible printed circuit board 15 is routed to a back side of the mold 16 , and is arranged below the backlight. LEDs 18 (Light Emitting Diode) which constitute a light source of the backlight are mounted on the flexible printed circuit board 15 , and are arranged on a side surface of the light guide plate 17 . On the flexible printed circuit board 15 , not only the LEDs 18 and a power source for the LEDs 18 , but also a power source for driving the liquid crystal display panel, lines for supplying signals to scanning lines and data signal lines and the like are arranged.
In FIG. 1 , an upper polarizer 14 is mounted on an upper surface of the liquid crystal display panel. A face plate 30 is mounted on the upper polarizer 14 . The face plate 30 is made of glass and has a thickness of 0.95 mm. Due to the formation of the face plate 30 using reinforced glass along with the possession of such a thickness larger than the thickness of the liquid crystal display panel, the face plate 30 has the sufficient mechanical strength for protecting the liquid crystal display panel. In addition to the above-mentioned advantageous effects, by properly chamfering the face plate described later, the deterioration of the strength of the face plate is prevented. The face plate 30 is adhered to the liquid crystal display panel, to be more specific, to the upper polarizer 14 using an acrylic adhesive material 31 .
FIG. 2 is a cross-sectional view taken along a line A-A in FIG. 1 and also is an exploded cross-sectional view. In the actual structure, the liquid crystal display panel and the backlight are housed in the inside of the mold 16 . The face plate 30 is adhered to the liquid crystal display panel. In FIG. 2 , the TFT substrate 11 and the color filter substrate 12 are arranged with a gap of several μm therebetween, and the liquid crystal is sandwiched between the TFT substrate 11 and the color filter substrate 12 . A sealing material 19 is arranged on peripheries of the TFT substrate 11 and the color filter substrate 12 and the liquid crystal is sealed inside the sealing material 19 .
On the TFT substrate 11 , in addition to the pixel electrodes and the TFTs, scanning lines, data signal lines and the like are arranged. These lines extend to the outside after penetrating the sealing material 19 , and are connected to a drive IC 13 or a flexible printed circuit board 15 . The flexible printed circuit board 15 extends to a position behind the backlight. The LEDs 18 mounted on the flexible printed circuit board 15 are arranged on a side surface of the light guide plate 17 and constitute the light source of the backlight. A plurality of LEDs 18 is mounted on the flexible printed circuit board 15 .
In FIG. 2 , the light guide plate 17 plays a role of directing the light from the LEDs 18 arranged on the side surface thereof toward a liquid-crystal-display-panel side. A reflection sheet 25 is provided for directing the light which advances downwardly from the light guide plate 17 toward the liquid-crystal-display-panel side. A lower diffusion sheet 21 is arranged on the light guide plate 17 . Although the plurality of LEDs 18 is arranged on the side surface of the light guide plate 17 , a gap exists between the LEDs 18 and the side surface of the light guide plate 17 and hence, light which advances upwardly from the light guide plate 17 becomes non-uniform. That is, a portion of the light guide plate 17 in the vicinity of the LEDs 18 becomes brighter than other portions of the light guide plate 17 . The lower diffusion sheet 21 is provided to cope with such non-uniformity of light and plays a role of making the light advancing upwardly from the light guide plate 17 uniform.
A lower prism sheet 22 is arranged on the lower diffusion sheet 21 . A large number of prisms which extends in the lateral direction of a screen is formed on the lower prism sheet 22 at fixed intervals, for example, at intervals of approximately 50 μm. Due to such prisms, light which is emitted from the light guide plate 17 focuses the light which tends to spread in the longitudinal direction of the screen in the direction perpendicular to the liquid crystal display panel. An upper prism sheet 23 is arranged on the lower prism sheet 22 . A large number of prisms which extends in the direction orthogonal to the prisms formed on the lower prism sheet 22 , that is, in the longitudinal direction of the screen, is formed on the upper prism sheet 23 at fixed intervals, for example, at intervals of approximately 50 μm. Due to such prisms, light which is emitted from the light guide plate 17 focuses the light which tends to spread in the lateral direction of the screen in the direction perpendicular to the liquid crystal display panel. In this manner, with the use of the lower prism sheet 22 and the upper prism sheet 23 , it is possible to focus the light which tends to spread in the longitudinal direction as well as in the lateral direction of the screen in the direction perpendicular to the screen. That is, with the use of the lower prism sheet 22 and the upper prism sheet 23 , it is possible to increase the front brightness.
An upper diffusion sheet 24 is arranged on the upper prism sheet 23 . The prisms which extend in the fixed direction are arranged on the prism sheets at intervals of 50 μm, for example. That is, bright and dark stripes are formed at intervals of 50 μm. On the other hand, on the liquid crystal display panel, scanning lines are formed in the lateral direction of the screen at fixed intervals, and data signal lines are formed in the longitudinal direction of the screen at fixed intervals. Accordingly, the interference occurs between the scanning lines and the lower prism sheet 22 or between the data signal lines and the upper prism sheet 23 thus generating moiré. The upper diffusion sheet 24 plays a role of reducing this moiré by making use of a diffusion effect.
The light which passes through the upper diffusion sheet is incident on the lower polarizer 20 which is adhered to the liquid crystal display panel and hence, the light is polarized. Transmissivity of the polarized light is controlled by the liquid crystal for every pixel in the inside of the liquid crystal display panel so as to form an image. The light which passes through the liquid crystal display panel is polarized again by the upper polarizer 14 and a viewer recognizes the light with his/her naked eyes.
The face plate 30 is arranged on the upper polarizer 14 . The face plate 30 according to the present invention is made of glass. Glass exhibits high hardness and hence, the face plate 30 made of glass can prevent flaws or the like formed on a front surface of the face plate 30 compared to the face plate 30 made of plastic or the like. The face plate 30 is adhered to the upper polarizer 14 using an adhesive material 31 . FIG. 3 shows a state after the face plate 30 is adhered to the upper polarizer 14 . A thickness of the face plate 30 is 0.95 mm. Compared to a thickness of the whole liquid crystal display panel including the TFT substrate 11 and the color filter substrate 12 which is 0.6 mm, the thickness of the face plate 30 is set considerably large. Further, reinforcing treatment is applied to the face plate 30 and hence, the face plate 30 exhibits the strength considerably higher than the strength of the liquid crystal display panel. Accordingly, it is possible to sufficiently enhance a mechanical protection effect. In addition to the above-mentioned advantageous effects, as described later, the face plate is suitably chamfered at the corner portions and the side portions thereof thus preventing the deterioration of the strength of the face plate.
The face plate 30 is smaller than the upper polarizer 14 in size. It is preferable to set both of a short-axis length and a long-axis length of the face plate 30 shorter than a short-axis length and a long-axis length of the upper polarizer 14 by 0.5 mm or more respectively. Conventionally, the face plate 30 is arranged in a spaced-apart manner from the liquid crystal display panel with a gap therebetween. One of the reasons is that when the liquid crystal display panel and the face plate 30 are adhered to each other, the uniform adhesion cannot be acquired due to the intrusion of bubbles or the like. According to the present invention, by making the size of the face plate 30 smaller than the size of the polarizer, the probability of the intrusion of bubbles or the like at the time of adhering the face plate 30 to the liquid crystal display panel can be extremely lowered thus realizing the adhesion of the face plate 30 to the liquid crystal display panel in practice use.
Further, according to the present invention, by specifying a material of the adhesive material 31 used for adhering the face plate 30 to the liquid crystal display panel, the face plate 30 can be uniformly adhered to the liquid crystal display panel. That is, when the face plate 30 is adhered to the upper polarizer 14 of the liquid crystal display panel, the adhesive material 31 is in a liquid state. At the time of initially adhering the upper polarizer and the face plate to each other, the adhesive material is in a liquid state and hence, even when there exists a slight gap between the face plate 30 and the upper polarizer 14 , the gap is easily filled with the liquid. Accordingly, it is possible to prevent the intrusion of the bubbles.
By radiating ultraviolet rays to the adhesive material 31 which is in a liquid state initially, the adhesive material 31 is cured so that the face plate 30 is fixed to the liquid crystal display panel. Due to such a process, it is possible to uniformly adhere the face plate 30 to the liquid crystal display panel. As the adhesive material 31 which is initially in a liquid state, for example, an acrylic resin which contains 27% to 30% of acrylic oligomer, UV-reactive monomer, an additive for photo-polymerization and the like can be used. A thickness of the adhesive material 31 after curing is several μm and hence, it is possible to prevent a phenomenon that an image appears as a duplicate image described in conjunction with FIG. 10 as a conventional example.
FIG. 4A to FIG. 4C show a shape of the face plate 30 . The face plate 30 is provided for mechanically protecting the liquid crystal display panel and hence, the face plate 30 per se is required to be mechanically strong. The thickness t of the face plate 30 is set to 0.95 mm and reinforced glass is used as glass so as to increase the strength of the face plate 30 . However, to impart the sufficient strength to the face plate 30 , it is important to take a shape of the face plate 30 into consideration besides the material and the thickness of the face plate 30 . A particularly important point lies in a chamfer CC of corner portions and a chamfer C on side portions shown in FIG. 4A to FIG. 4C .
In FIG. 4A to FIG. 4C , the chamfer CC is formed on each corner portions. The chamfer CC is a portion which is formed by removing a sharp corner portion by shaving the corner of the glass substrate having a rectangular shape. In this embodiment, the face plate 30 is chamfered simultaneously with the formation of an accurate profile of the face plate 30 by polishing peripheries of the face plate 30 . A value C 1 which determines the shape of the chamfer CC is 0.5 mm. The value C 1 may preferably be set to 0.5 mm or more. However, when the value C 1 is set to 0.3 mm or more, it is possible to acquire the advantageous effect. On the other hand, a profile of the face plate 30 is formed smaller than a profile of the upper polarizer 14 and hence, when the value C 1 is excessively increased, the chamfer CC extends over a display region of the liquid crystal display panel. Accordingly, the value C 1 is usually set to 3 mm or less. Another significant advantageous effect acquired by the formation of the chamfers CC lies in that, by forming the chamfers on the face plate 30 , the face plate 30 is hardly peeled off from the liquid crystal display panel. According to an experiment, peeling-off of the face plate 30 from the liquid crystal display panel starts from the corner portion of the face plate 30 . Accordingly, by chamfering the corner portions of the face plate 30 , it is possible to prevent the peeling-off of the face plate 30 .
With respect to the strength of the face plate 30 , the next important point is the formation of the chamfer C on side portions shown in FIG. 4A to FIG. 4C . All sides of the face plate 30 are chamfered. Burrs are liable to be formed on the side portion, and when burrs are generated in such a portion, the generated burrs may cause cracks. In this embodiment, a value C 1 indicative of a size of the chamfer shown in FIG. 4C is set to 0.15 mm. The chamfer on the side portion may preferably be set to 0.15 mm or more. However, when the value C 1 is set to 0.05 mm or more, it is possible to acquire the advantageous effect. On the other hand, an upper limit of a value C 2 of the chamfer C is determined based on the relationship between the thickness of the face plate 30 and the display region. When the thickness of the face plate 30 is set to 0.95 mm as in the case of this embodiment, the upper limit of the value C 2 is set to approximately 0.3 mm.
Further, in view of the relationship that the face plate 30 is smaller than the upper polarizer 14 in size, when the value C 2 of the chamfer C is increased, the chamfered portions extend over the display region. Accordingly, the upper limit of the value C 2 varies based on the thickness of the face plate 30 , a size of a screen or the like. The formation of the chamfers C also exhibits an advantageous effect in view of not only the strength of the glass but also image quality. That is, when the face plate 30 is not chamfered, burrs are liable to be formed on the side portion. These burrs are visually recognized as white dots in the periphery of the display screen, and these dots are counted as one of image quality defects. By suppressing the burrs by chamfering the face plate 30 , it is possible to prevent the white dot defect in peripheries of the screen.
In this embodiment, IG3 (trade name and made by ISHIZUKA GLASS CO., LTD.) is used as a material of the face plate 30 . This glass possesses the strength by 1.5 times as large as the strength of normal soda glass. However, manufacturing steps of the face plate 30 described later includes a process for reinforcing the glass in a chemical solution and hence, normal soda glass can be also used in this embodiment.
FIG. 5 is a flowchart showing a process of manufacturing the face plate 30 shown in FIG. 4 . In FIG. 5 , a large number of face plates 30 are cut from a large glass substrate in step 1 . Here, the face plate 30 is cut with a size slightly larger than a final size. This is because the face plate 30 is formed in an accurate size by polishing performed later. A large number of burrs are formed on the face plate 30 obtained by cutting the glass substrate in step 1 . In succeeding steps, there may be a case in which the glass cracks at a portion thereof where the burr is formed. In step 2 , the face plate 30 is chamfered for removing the burrs. A size of a chamfer at the time of such chamfering differs from a size of the chamfer in a final shape.
An initial thickness of the face plate 30 is 1.4 mm. In step 3 , a thickness of the face plate 30 is decreased to 1.0 mm by coarse polishing. A large number of flaws or the like is formed on normal glass and hence, the normal glass is not suitable for the face plate 30 of the liquid crystal display panel when the normal glass is used as it is. Accordingly, it is necessary to make a surface of the glass uniform by polishing. After finishing coarse polishing, small polishing flaws are formed on the glass surface so that the glass exhibits a frosted glass state.
In step 4 , a profile of the glass substrate is polished to bring the size of the profile into an accurate value. FIG. 6 is a schematic view showing profile polishing of the glass in step 4 . In FIG. 6 , a face plate 30 G is mounted on a disc-like roller ROL. When the roller ROL is rotated in the direction A, the face plate 30 G is also rotated in the same direction. A cam CM having a four-leaf-clover shape is coaxially mounted on a disc-like grinder GR which polishes the face plate 30 . The grinder GR and the cam CM are rotated in the direction B. The grinder GR and the face plate 30 are in contact and hence, the profile of the face plate 30 is polished.
The roller ROL which rotates the face plate 30 is brought into contact with the cam CM. Accordingly, by moving the grinder GR in the direction C, an amount which the face plate 30 is shaved can be adjusted. Further, the roller ROL is moved tracing the cam CM and hence, the grinder GR can follow the profile of the rectangular face plate 30 . Due to the complicated shape of the cam CM as shown in FIG. 6 , it is possible to form the chamfer CC with the value C 1 of 0.5 mm on the corner portion of the face plate 30 . Here, as described above, when the value C 1 is 0.3 mm or more, it is possible to acquire the advantageous effect. The chamfer CC formed on each corner portion of the face plate 30 is extremely important for enhancing the strength of the face plate 30 and hence, the profile of the face plate 30 is controlled by using the grinder shown in FIG. 6 .
In this manner, the profile of the face plate 30 is determined and, thereafter, in step 5 shown in FIG. 5 , the chamfer C is formed on the face plate 30 . In step 5 , in the same manner as the chamfer C in the final state, the chamfer C with the value C 2 of 0.15 mm is formed on the face plate 30 . As described above, when the value C 2 is set to 0.05 mm or more, it is possible to acquire the advantageous effect.
Next, in step 5 shown in FIG. 5 , precision polishing of the face plate 30 in the thickness direction is performed. Although the face plate 30 is polished in the thickness direction by coarse polishing in step 3 , in a state after coarse polishing, a surface of the face plate 30 exhibits a frosted glass state. In step 5 , the surface of the face plate 30 is polished into a transparent state by precision polishing. The surface of the face plate 30 is slightly shaved by this precision polishing and a plate thickness of the face plate 30 is decreased from 1.0 mm to 0.95 mm. That is, the face plate is polished by 0.025 mm on each side. This polishing amount is small and hence, the chamfer C formed in step 5 is not largely influenced.
Then, in step 7 , a polishing agent is removed by cleaning. After cleaning, in step 8 , chemical reinforcement treatment is applied to the face plate 30 . The chemical reinforcement treatment is performed for chemically strengthening glass with an action of ions by immersing the face plate 30 into a chemical solution of high temperature. The chemical reinforcement treatment is performed by immersing the face plate 30 in the chemical solution at a temperature of approximately 400° C. for approximately 10 hours. Although the chemical reinforcement treatment takes time, the treatment can treat a large number of face plates 30 at a time.
After performing the chemical reinforcement treatment, the face plate 30 is cleaned by applying ultrasonic cleaning to the face plate 30 thus removing chemical substances remaining on the surface of the face plate 30 . Then, the face plate 30 is wrapped with a sheet and is shipped to a liquid crystal display panel maker.
FIG. 7 is a schematic view showing a state in which the face plate 30 is wrapped with a wrapping sheet for shipping. Conventionally, a sheet for such wrapping adopts the following constitution. The wrapping sheet is formed of a polyethylene film. An adhesive material is applied to a surface of the polyethylene film, and the face plates 30 are fixed to the polyethylene film using the adhesive material. A thickness of the whole wrapping film 40 is 70 μm, while a thickness of the adhesive material is 10 μm to 20 μm.
After receiving the face plates 30 , the liquid crystal display panel maker cleans the face plates 30 . When the face plate 30 is fixed to the wrapping film 40 using the adhesive material, as described in the related art, the adhesive material is adhered to the face plate 30 . The adhesive material which is adhered to the face plate 30 is peeled off at the time of cleaning the face plate 30 and remains in the cleaning liquid. This adhesive agent is adhered to the face plate 30 again leading to insufficient cleaning. To cope with this insufficient cleaning, in this embodiment, instead of applying the adhesive material to the wrapping film 40 , the face plate 30 is fixed to the wrapping film 40 using static electricity generated on the polyethylene film. After fixing the face plate 30 to the wrapping film 40 , the face plate 30 is covered with the wrapping sheet 40 thus protecting and fixing the face plate 30 .
Embodiment 2
FIG. 8A to FIG. 8C show a shape of a face plate 30 used in an embodiment 2 of the present invention. The constitution of the liquid crystal display device of this embodiment is substantially equal to the constitution of the liquid crystal display device explained in conjunction with FIG. 1 and FIG. 2 . In FIG. 8 , a point which makes this embodiment different from the embodiment 1 in the shape of the face plate 30 lies in that a rounded portion RC is formed on each corner portions instead of forming the chamfer. The rounded portions RC are formed on the face plate 30 to enhance the strength of the face plate 30 as well as to cope with the peeling-off of the face plate 30 .
In this embodiment, instead of the chamfers, the rounded portions are formed on the face plate 30 . Since corner portions are not formed in a square shape in this embodiment, the strength of the glass can be further advantageously enhanced. Further, this embodiment can also acquire the advantageous effect that peeling-off of the face plate 30 from the liquid crystal display panel can be prevented in the same manner as the embodiment 1. A size of the rounded portion RC is 0.5 mm in this embodiment. When the size of the rounded portion RC is 0.3 mm or more, it is possible to acquire the advantageous effect attributed to rounding of the corner portion. Further, when the size of the rounded portions RC is excessively increased, the rounded portion RC extends over the corner of the display surface and hence, it is necessary to determine the size of the rounded portion RC by taking a display area into consideration. In general, the size of the rounded portion RC is set to 3 mm or less. However, an upper limit of the size of the rounded portion RC is determined based on the size of an effective display screen and hence, it is not necessary to set an upper limit with respect to strength of the face plate 30 or peeling-off of the face plate 30 .
Also in this embodiment, the chamfers C are formed on side portions of the face plate 30 . In the same manner as the embodiment 1, the chamfers C are formed on the face plate 30 for enhancing the strength of the face plate 30 and, at the same time, for preventing the generation of white dots in the periphery of the display screen. A size C 2 of the chamfer C shown in FIG. 8C is set to 0.15 mm in the same manner as the embodiment 1. The side portion may preferably be chamfered with a cutting size of 0.15 mm or more. However, when the side portion is chamfered with a cutting size of 0.05 mm or more, it is possible to acquire the advantageous effect. On the other hand, in the same manner as the embodiment 1, an upper limit of the cutting size of the chamfer C 2 is determined based on the relationship between the plate thickness of the face plate 30 and the display region.
In the same manner as the embodiment 1, the plate thickness of the face plate 30 in this embodiment is set to 0.95 mm. Further, although IG3 (trade name and made by ISHIZUKA GLASS CO., LTD.) is used as a glass material in this embodiment, soda glass may be used as the glass material in the same manner as the embodiment 1. The process flow for manufacturing the face plate 30 of this embodiment is substantially equal to the process flow for manufacturing the face plate 30 of the embodiment 1 explained in conjunction with FIG. 5 . Here, the face plate 30 of this embodiment differs from the face plate 30 of the embodiment 1 in profile and hence, this embodiment differs from the first embodiment in polishing of the profile of the face plate 30 in step 4 explained in conjunction with FIG. 5 .
FIG. 9A to FIG. 9C are schematic views showing a polishing machine for accurately forming the profile of the face plate 30 shown in FIG. 8 . Also in FIG. 9 , this embodiment adopts the substantially same basic constitution as the constitution of the polishing machine shown in FIG. 6 . That is, the profile of the face plate 30 is polished by moving a grinder GR along with the movement of a roller ROL which corresponds to a cam CM. FIG. 9A is a side schematic view of the polishing machine, FIG. 9B is a view showing the polishing machine shown in FIG. 9A as viewed in the direction A in FIG. 9A , and FIG. 9C is a view showing the polishing machine shown in FIG. 9A as viewed in the direction B.
In FIG. 9A , FIG. 9B and FIG. 9C , for facilitating the understanding of the drawing, although the cam CM is depicted in a state that the cam CM is in a spaced-apart manner from the roller ROL, the cam CM is in contact with the roller ROL in an actual state. Further, in FIG. 9A , FIG. 9B and FIG. 9C , although the grinder GR is depicted in a state that the grinder GR is spaced-apart from the face plate 30 , the grinder GR is in contact with the face plate 30 in an actual state.
When the roller ROL is rotated, a rotary shaft AX is moved tracing the shape of the cam CM. Then, the grinder GR which is mounted coaxially with the roller ROL is also moved in the same manner as the roller ROL. That is, the grinder GR is moved tracing the shape of the cam CM. The face plate 30 is brought into contact with the grinder GR and hence, a profile of the face plate 30 is polished by the rotating grinder GR tracing the shape of the cam CM. The shape of the cam CM becomes a shape similar to a final profile of the face plate 30 . By forming a rounded portion R corresponding to a corner portion of the face plate 30 on the corner portion of the cam CM, the rounded portion R of the face plate 30 is formed.
Steps 5 to 10 which follow step 4 in which the profile of the face plate 30 is determined are substantially equal to steps 5 to 10 of the embodiment 1. Step of adhering the face plate 30 produced in the above-mentioned manner to the liquid crystal display panel is substantially equal to the corresponding step explained in conjunction with the embodiment 1. Further, the profile of the face plate 30 of this embodiment is formed smaller than the size of the upper polarizer 14 adhered to the liquid crystal display panel in the same manner as the embodiment 1. In the same manner as the embodiment 1, the short-axis length and the long-axis length of the face plate 30 may preferably be set smaller than the short-axis length and the long-axis length of the upper polarizer 14 by 0.5 mm or more. According to this embodiment, by forming the rounded portion R on the corner portion of the face plate 30 , it is possible to increase the strength of the face plate 30 and, at the same time, it is possible to prevent peeling-off of the face plate 30 from the liquid crystal display panel at the corner portions.
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The present invention mechanically protects a surface of a miniaturized liquid crystal display device for mobile phone or the like without deteriorating image quality and without increasing a thickness of a whole display device. To achieve such an object, in the present invention, a liquid crystal display panel is constituted of a TFT substrate and a color filter substrate, a lower polarizer is adhered to a lower surface of the TFT substrate, and an upper polarizer is adhered to an upper surface of the color filter substrate. A face plate is adhered to the upper polarizer using an acrylic adhesive material which is cured by ultraviolet rays. For enhancing strength and adhesion property of the face plate, corners and side portions of the face plate are chamfered. By making a profile of the face plate smaller than a profile of the upper polarizer, the adhesion property of the face plate is enhanced. The present invention can protect the surface of the liquid crystal display panel without deteriorating image quality and without largely increasing a thickness of the display device.
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BACKGROUND OF THE INVENTION
ATM communication system with a modular structure serve for the connection of communication terminals with high transmission rates in private and public communication networks. The transmission and switching of the messages take place using the Asynchronous Transfer Mode, in which the information items to be transmitted are transmitted and switched in packet form, i.e. with packets of fixed length (cells) in accordance with CCITT standard I.361. Internationally standardized transport bit rates are currently 155 and 622 Mbit/s. With the aid of channel and path information inserted in the cell headers of the cells, the cells are transmitted over a virtual transmission channel from one communication terminal via a communication system to a particular communication terminal. The transmission channel is set up by signaling from a subscriber--as in the known time-division multiplex communication systems--or by an administrative input at the communication system and is logically retained for the duration of the connection. The bandwidth of such a transmission channel is flexible and is applied for when the connection is established. Such basic functions of ATM communication systems are known from the publication "ATM Technologie fur zukunftige Breitbandnetze" ATM Technology for Future Broadband Networks!, Siemens, 1992.
A structure of an ATM communication system having such functions is known from telcom report 13, "Mit ATM zur bitvariablen Kommunikation" With ATM to Bit-Variable Communication!, 1990, pages 4-7. In the case of this structure, the ATM communication system or the ATM switching device is formed by a line trunk group having subscriber line modules, by an ATM switching matrix and by a central controller, the central controller being connected directly to the subscriber line modules for a transmission of switching, operation and dependability information. In this concept, a modification of the configuration of the communication system involves considerable hardware and software modifications.
A further ATM communication system for the switching of packeted cells between ATM communication terminals over dial-up or fixed connections is known from the publication IEEE IN HOUSTON GLOBECOM '93 . . . . In this system, there are a plurality of subscriber line modules which are equipped with SDH subscriber interfaces and are known as "Line Cards" connected to an ATM switching matrix, which is provided with a plurality of bidirectional terminal connections and operates by ATM, in each case via a multiplexer/demultiplexer stage referred to as a "Fabric Interface". It is also the case with this concept that, in particular, configuration modifications to the switching software bring about considerable hardware and software modifications.
Furthermore, in European Patent Specification EP-A2 0 358 597 there is described a modular communication system having a switching device and having a personal computer realizing a control device, there being integrated in the switching device a switching matrix of which the terminal connections are connected to subscriber line modules. Both in the switching device and in the control device there are defined corresponding interfaces, which permit an exchange of information or data between the two units. The control device according to the disclosed arrangement serves for expanding an existing switching device by adding any desired additional features, while ensuring the necessary operational dependability. Consequently, software modifications, in particular to the switching software, in the switching device likewise cause software modifications in the control device.
SUMMARY OF THE INVENTION
To be regarded as the object on which the invention is based is that of providing a structure of an ATM communication system with greater modularity and more flexible configuration. The object is achieved by a modular ATM communication system for the switching of packeted cells between ATM communication terminals over dial-up or fixed connections. The system has at least one switching device with a central device. The switching device has an ATM switching matrix module, which is provided with a plurality of bidirectional terminal connections and operates using the Asynchronous Transfer Mode. The terminal connections thereof which are connected to at least one subscriber line module, realizing at least one SDH subscriber interface, and to a communication module. A clock module, providing the clock signals for the ATM switching matrix module, the subscriber line modules and the communication module. The central device is formed by a personal computer, which controls the switching device in terms of operation, switching and administration. A processor-controlled communication adaptor controls and monitors the exchange of information with the switching device and is connected to one of the subscriber interfaces and to the personal computer. The system allows transmission of switching, dependability and administration information, there being defined in the communication module and in the control device a transport interface, and also a switching interface, a dependability interface and an operation interface.
Advantageous developments of the present invention are as follows.
The communication module is equipped with a bus system, to which there is connected a first cell header module with an assigned RAM memory. Internal cell headers, provided for self-control of the cells containing switching, operation and dependability information by the ATM switching matrix module are formed and are attached to the cells. There is connected a second cell header module with an assigned RAM memory, in which the internal cell headers are removed before a transmission of the cells containing switching, operation and dependability information to the control device. There is connected a segmentation and desegmentation module, inserting into cells the switching, operation or dependability information to be transmitted or removing such information from the transmitted cells. There is connected a microprocessor system, controlling and monitoring the communication module. In a further clock module, the clock signals for a transmission to the ATM switching matrix module and the control device are derived from the reference clock signals transmitted from the clock module and are distributed to the components of the communication module.
The communication adaptor is formed by a segmentation and desegmentation module, which has an assigned buffer memory and realizes an SDH subscriber interface. A microprocessor system is data isolated from a DMA controller by two local buses. An EISA control module realizes an EISA bus connection, an EISA communication bus being arranged in the personal computer.
To be regarded as an essential aspect of the communication system according to the invention is that the communication system is divided into two devices, namely into a switching device and a control device, and the control device is connected like an ATM communication terminal to the switching device. In the switching device, although the cells are switched with the aid of the ATM switching matrix, the switching control is effected by the switching program implemented in the control device. For information transmission, the switching device is equipped with a communication module and the control device is equipped with a communication adaptor. For this purpose, to allow transmission of switching, dependability and administrative information, there is defined in the communication module and in the control device a transport interface, and also a switching interface, a dependability interface and an operation interface. This definition achieves the effect of largely isolating the hardware and software and consequently of considerably increasing the modularity and freedom of configuration of ATM communication systems, in particular relatively small ATM communication systems. The control device is advantageously realized by a commercially available personal computer, just having an adaptor incorporated in its circuitry. In the program memories of the personal computer there are stored all the essential programs for the switching, operation and dependability control of the switching device. This concept of the control device in a personal computer on the one hand achieves a particularly cost-effective setup and on the other hand makes it possible to dispense with a separate operator terminal.
The communication module is advantageously equipped with a bus system, to which there is connected a cell header module with an assigned RAM memory, in which internal cell headers provided for the self-control of the cells containing switching, operation and dependability information by the switching matrix are formed and are attached to the cells, and there is connected a further cell header module with an assigned RAM memory, in which the internal cell headers are removed before a transmission of the cells containing switching, operation and dependability information to the control device. Furthermore, there is connected to the bus system, to allow packing of the information to be transmitted in cells and for unpacking the information from transmitted cells, a segmentation and desegmentation module and a microprocessor system, controlling and monitoring the communication module, and also a clock pulse processing module, in which the transmission clock pulses for a transmission to the ATM switching matrix module and the control device are derived from the reference clock signals transmitted from the clock module and are distributed to the components of the communication module. This advantageous concept additionally makes it possible to realize a cost-effect setup by means of commercially available and customer-programmable integrated circuits.
According to a further advantageous refinement of the communication system according to the invention, the communication adaptor is formed by a line module, realizing an ATM subscriber connection, and an EISA control module, realizing an EISA bus connection, an EISA communication bus being arranged in the personal computer. This concept achieves a high data throughput for a cost-effective amount of expenditure to realize the setup.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention which are believed to be novel, are set forth with particularity in the appended claims. The invention, together with further objects and advantages, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several Figures of which like reference numerals identify like elements, and in which:
FIG. 1 shows the structure of an ATM communication system with a modular structure,
FIG. 2 shows the construction of the communication module,
FIG. 3 shows the construction of the communication adaptor and
FIG. 4 shows the construction of the subscriber line module.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a communication system KS, which is formed by a switching device SB and by a control device CB.
Arranged in the switching device SB is an ATM switching matrix module ASN, operating by the Asynchronous Transfer Mode, a plurality of subscriber line modules SLMP, a communication module KM and a clock module TM.
The ATM switching matrix module ASN is designed, for example, with sixteen bidirectional terminal connections A with a transmission rate of 175.805 Mbit/s each. For the switching of cells formed on the basis of the Asynchronous Transfer Mode, they are switched in accordance with the accompanying switching information via the ATM switching matrix module ASN according to the self-switching principle. This means that, with the aid of the accompanying switching information--for example in a preceding, additional cell header--a cell is switched independently via the switching matrix module ASN. The information items are physically transmitted by differential shifted ECL (Emitter Coupled Logic) signals, NRZ (Non Return to Zero)-coded, to each of the sixteen terminal connections A of the processor-controlled ATM switching matrix module ASN. The ATM switching matrix module ASN is realized, for example, according to the switching matrix disclosed in European reference EP 0 329 005 B1.
A subscriber line module SLMP or a communication module KM can be connected to each of the sixteen terminal connections A, a communication module KM being provided in a switching device SB. In FIG. 1, two subscriber line modules SLMP are represented by way of example for a maximum of fifteen connectable subscriber line modules.
In the clock module TM, clock signals to required for the operation of the ATM switching matrix module ASN, of the subscriber line modules SLMP and of the communication module KM are formed and are transmitted over separate clock lines TL to the respective components of the switching device SB. These clock signals ts are intended in particular for the operation of the microprocessors used in the components SLMP, ASN, KM of the switching device SB and for the transmission of the information via the interfaces in accordance with the switching device.
For the connection of communication terminals KE operating by the Asynchronous Transfer Mode, the subscriber line modules SLMP are equipped with an SDH (Synchronous Digital Hierarchy) interface SDH with a transmission rate of 155 Mbit/s. The data or information transmission via the SDH interface SDH is carried out in accordance with CCITT recommendation I.121 (User Network Interface UNI) in the Synchronous Transfer Mode (STM-1) at a transmission rate of 155.52 Mbit/s. The construction and mode of operation of the subscriber line modules SLMP is explained in more detail in FIG. 3.
Indicated by a rectangle represented in dashed lines and inserted between the communication terminal KE and the subscriber line module SLMP are transmission modules UM, with the aid of which remote communication terminals KE are connected to the switching device SB. The transmission modules UM contain transmission devices--not shown--for electrical transmission of the cell-oriented information over coaxial cables in accordance with CCITT recommendation G.703 or for an optical transmission over optical waveguides in accordance with CCITT recommendations G.957/958.
Such broadband communication terminals KE for the connection to the switching device SB can be realized by a multiplicity of devices. Mentioned by way of example are terminal connections to further ATM communication systems KS, adaptors for the connection of local area networks, ISDN switching devices--for example to the HICOM switching system--and ATM workstations.
With the aid of the communication module KM, the cells to be transmitted from the control device CB or to it are controlled. For this purpose, a layer 2 function, corresponding to the ISO layer model, and a layer 3 function, intended for the switching of the cells within the switching device SB, are realized in the communication module KM. Furthermore, the communication module KM comprises a switching subfunction, with the aid of which switching, administrative and operation messages transmitted from the control device CB and in the reverse direction are transformed into messages conforming to the switching device, i.e. in relation to the physical design of the switching device SB.
For the communication of the switching device SB with the control device CB, the latter is equipped with a communication adaptor CA. The communication adaptor CA is arranged in a personal computer PC, realizing the control device CB. In the known way, the personal computer PC, realized by a commercially available personal computer, has a screen device BE, an input device EE, mass storage devices HD--for example hard disks--and a microprocessor system MPS. In addition, an adaptation module EISA, realizing an EISA bus BEI, is integrated in the personal computer PC, the communication adaptor CA being connected to the EISA bus BEI. The components BE, EE, MPS, HD, EISA of the personal computer PC communicate via an internal local bus LB. The EISA bus is a bus which is isolated from the internal, local bus LB and has a bit width of 32 bits and a transfer rate of 33 Mbyte/s.
FIG. 2 shows the communication module KM in a block diagram. Arranged in this communication module is a bus system LB of a microprocessor system MPS. The microprocessor system MPS is formed by a commercially available microprocessor CPU--for example a microprocessor SAB 80 386 DX from the Siemens company--and by a main memory RAM and a program memory FLA. The program memory FLA is preferably realized by a flash memory. The components CPU, RAM, FLA of the microprocessor system MPS are in each case connected to the bus system LB formed by address, data and control lines.
For sending and receiving cells Z to and from the terminal connection A of the ATM switching matrix module, two cell header modules HTCE, RPCE, which are each connected to the bus system LB, are provided in the communication module KM. With the aid of the first cell header module HTCE, internally formed cell headers are attached to the cells Z to be transmitted, to allow self-controlling switching via the ATM switching matrix module ASN. With the aid of these internal cell headers, the cells Z are controlled by the ATM switching matrix module ASN, as explained in FIG. 1. With the aid of the second cell header module RPCE, the internal cell headers of the cells Z transmitted from the ATM switching matrix module ASN are removed. Cells Z whose receivers are within the switching device SB have in the internal cell header further special entries, with the aid of which further, internal cell headers are formed to allow transmission to a component of the switching device VE, are attached to the corresponding cell Z and are transmitted via the ATM switching matrix module ASM to the respective component. For the generation of the internal cell headers and their removal under real-time conditions, the additional data required for this purpose are stored in RAM memories HRAM, RRAM respectively assigned to the cell header modules HTCE, RPCE. The two cell header modules HTCE, RPCE are realized, for example, in each case in an ASIC (Application Specific Integrated Circuit).
Connected furthermore to the bus system LB is a segmentation and desegmentation module SARE. With the aid of this segmentation and desegmentation module SARE in accordance with CCITT recommendation I.363, the information formed by the microprocessor system MPS is packed in cells Z and the cells Z transmitted from another module in the switching device SB or the control device CB are unpacked, ie. the information is taken out of the cells Z and is transmitted to the microprocessor system MPS. This segmentation and desegmentation function is required whenever, to allow an assessment or response in or by the microprocessor system MPS, information is transmitted to the latter or is transmitted from the latter to other modules.
With the aid of the microprocessor system MPS, the switching, operation or dependability information transmitted by the control device CP or the components SLMP, ASN, TM is assessed and, dependent on the content of the transmitted information, corresponding responses are initiated or passed on.
Provided in the communication module KM is a further clock module TMK and a power supply SV. With the aid of the further clock module TMK, the clock signals ts required for the clock control of the two cell header modules HTCE, RPCE and of the segmentation and desegmentation module SARE are derived from the reference clock signals rts, transmitted by the clock module TM, and are transmitted to said modules. The voltages US required for the operation of the components of the communication module KM are derived from a central power supply UZ with the aid of the power supply SV.
FIG. 3 shows the communication adaptor CA in a block diagram--the adaptor being outlined by dot-dashed lines. With the aid of an EISA control module ECON, arranged in the communication adaptor CA, the connection to the personal-computer internal EISA communication bus EISA is established. The EISA communication bus EISA, formed by data, address and control lines, has a bit width of 32 bits, a clock frequency of 8.33 MHz and a transfer rate of 33 Mbit/s. The EISA control module ECON represents the link to a first local bus LB1. This first local bus LB1, likewise formed by data, control and address lines, has a bit width of 16 bits and a clock frequency of 20 MHz. For rate adaptation between the EISA communication bus EISA and the first local bus LB1, a dynamic memory DSP is additionally inserted.
Between the first local bus LB1 and a second local bus LB2, an adaptation unit AE is provided for the dynamic exchange of data. With the aid of this adaptation unit AE, the data to be transmitted are adapted from the first local bus LB1 to the 32-bit-wide, second local bus LB2 at a clock frequency of 20 MHz, and vice versa. Both the first local bus LB1 and the second local bus LB2 are controlled by the microprocessor system--realized, for example, by a microprocessor system SAB 80 486 from the Siemens company. For rapid access to the program and data memory arranged in the microprocessor system MPS, a DMA (direct memory access) controller DMA is coupled to the first bus LB1. The DMA controller DMA is realized, for example, by the integrated circuit SAB 82 380 from the Siemens company.
For the realization of the subscriber line interface SDH, a segmentation and desegmentation module SARE is provided in the communication adaptor CA. With the aid of this segmentation and desegmentation module SARE, the information to be transmitted is packed in cells Z and unpacked. For the buffer storage of the information or cells Z to be sent from or received by the segmentation and desegmentation module SARE, a buffer memory BUF is connected to the second local bus LB2. An ATM transmission system--not shown--can be connected to the segmentation and desegmentation module SARE for an electrical transmission of the signals over a coaxial line or an optical transmission over optical waveguides (see explanations with respect to FIG. 2).
The communication adaptor CA serves for linking a personal computer--for example a Unix workstation--to the switching device SB. The communication adaptor CA can be used both for the connection of a personal computer PC, designed as controlling device CB, or a workstation and for the connection of multimedia communication terminals KE--for example multimedia workstations--to one another for the transmission of audio, video and data signals.
FIG. 4 shows the construction of a subscriber line module SLMP. For sending and receiving cells Z to and from the terminal connection A of the ATM switching matrix module ASN, two cell header modules HTCE, RPCE, connected to a local bus system LB, are provided in the subscriber line module SLMP--see also FIG. 2. With the aid of the first cell header module HTCE, ASN-internal cell headers are attached to the cells Z to be transmitted, to allow self-controlling switching via the ATM switching matrix module. With the aid of the internal cell headers, the cells Z are controlled by the ATM switching matrix module ASN, as explained in FIG. 1. With the aid of the second cell header module RPCE, the internal cell headers are removed from the cells Z transmitted by the ATM switching matrix module ASN. Cells Z which are to be transmitted to the subscriber line module SLMP are unpacked and sent via the local bus LB to a microprocessor system MPS to allow an assessment. For the generation of the internal cell headers and their removal under real-time conditions, the additional data required for this purpose are stored in RAM memories HRAM, RRAM respectively assigned to the cell header modules HTCE, RPCE. The two cell header modules HTCE, RPCE are realized, for example, in each case in an ASIC.
The microprocessor system MPS is formed by a microprocessor CPU, a program memory ROM and a main memory RAM. The microprocessor CPU is realized, for example, by a microprocessor SAB 80 C 186 from the Siemens company and the program memory ROM is realized, for example, by a flash EPROM.
The cells Z are transmitted from the first and to the second cell header module HTCE, RPCE through an adaptation module SOD. In the adaptation module SOD, the incoming cells Z are converted from synchronous transfer format (STM-1) into an asynchronous transfer format (ATM). In this conversion, the information is already transmitted or processed in parallel--for example 4-bit parallel. Furthermore, the scrambling or descrambling of the data or information transmitted is carried out in this adaptation module SOD. The adaptation module SOD is, furthermore, connected to a coding module CM, in which the parallel signals are converted into a serial information flow, and vice versa. Furthermore, a code conversion is carried out. In this conversion, the NRZ (Non Return to Zero)-coded signals are converted into CMI (Coded Mark Inversion)-coded signals at the SDH subscriber interface SDH. For the decoding or decoding in both directions, a clock regeneration is carried out in a clock regeneration module TR, connected to the coding module CM. For this purpose, additional filter circuits are implemented in the clock regeneration module TR. The subscriber interface SDH represents an asymmetrical interface with a serial data transmission, operating in the synchronous transfer mode, at a rate of 155.52 MBit/s. The adaptation module SOD is, furthermore, connected to the local bus LB, via which the adaptation module SOD is monitored and controlled by the microprocessor system MPS. The local bus LB is, furthermore, connected to a control logic device STL. With the aid of this control logic device, the subscriber line module SLMP is set to a defined initial state and optical displays indicating error states and operational states are controlled.
The local bus is, furthermore, connected to an interface module IS, in which a V.24 interface is realized, to allow checks and tests of the subscriber line module SLMP.
Furthermore, arranged in the subscriber line module SLMP is a further clock module TMS, with the aid of which the clock signals ts required for the clock control of the two cell header modules HTCE, RPCE and also of the adaptation module SOD and of the microprocessor system MPS are derived from the reference clock signals rts, transmitted from the clock module TM, and are transmitted to these modules.
With the aid of the programs stored in the program memory ROM, all the messages received from the communication module KM are managed in the subscriber line module SLMP, the setting up and clearing down of ATM fixed or dial-up connections are controlled by setting a translator in the first cell header module HTCE and the components of the subscriber line module SLMB are monitored. Furthermore, all the switching, operation and dependability messages which are to be transmitted to the components of the switching device SB or are transmitted by them are saved in accordance with the layer 2 procedure--ie. by the HDLC transmission procedure--and are transmitted to the respective components via the ATM switching matrix module ASN. For this purpose, a corresponding internal cell header is to be attached to the respective cells Z.
The invention is not limited to the particular details of the apparatus depicted and other modifications and applications are contemplated. Certain other changes may be made in the above described apparatus without departing from the true spirit and scope of the invention herein involved. It is intended, therefore, that the subject matter in the above depiction shall be interpreted as illustrative and not in a limiting sense.
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An ATM communication system with a modular structure for the switching of packeted cells (Z) between ATM communication terminals (KE) over dial-up or fixed connections has a switching device (SB) and a remote control device (CB). Arranged in the switching device (SB) is an ATM switching matrix module (ASN), at least one subscriber line module (SLMP), a communication module (KM) and a clock module (TM), and the control device (CB) is formed by a personal computer (PC) which controls the switching device (SB) in terms of operation, switching and administration and in which a processor-controlled communication adaptor (CA) is provided for the exchange of information with the switching device (SB). This concept of a switching device (SB) and a separate control device (CA) in a personal computer (PC) achieves the effect of largely isolating hardware and software and brings about a considerable increase in the modularity and freedom of configuration of ATM communication systems (KS), in particular relatively small ATM communication systems.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to electronic semiconductor devices, and, more particularly, to high frequency field effect power transistors.
2. Description of the Related Art
Microwave power transistors typically are metal semiconductor field effect transistors (MESFETs) with recessed gates and n type gallium arsenide (GaAs) semiconductor channels. A recessed gate lengthens the surface leakage path from gate to drain and permits the channel electrons to be slightly removed from the surface and attendant surface state scattering. The cut-off frequency (f t ) of conventional GaAs MESFETs depends on the gate length roughly as ##EQU1## where G mO is the intrinsic transconductance, C gs is the gate-source capacitance, v is the average carrier drift velocity in the channel, L is the effective channel length (gate length), and τ is the average transit time for a carrier traversing the channel. Thus reducing gate length increases f t , and millimeter-wave GaAs MESFETs for 60 GHz operation typically have 0.25 μm long gates. But to limit short channel effects, the channel thickness (usually denoted by a) must be much less than one third of the gate length (i.e., L>>3a); see H. Daembkes et al, Improved Short-Channel GaAs MESFET's by Use of Higher Doping Concentration, 31 IEEE Tr.Elec.Dev. 1032 (1984). Thus, the channel thickness is decreased with decreasing gate length. However, device power depends upon the channel current, so the doping concentration in the channel must be increased to compensate for the thinner channel. However, the resultant high doping concentrations lower the breakdown voltage (V b ) and power density per unit gate width. And because of the nonuniform field distribution in the channel, the breakdown voltage is also proportional to the total charge in the depletion layer under the gate at pinch-off; see W. Frensley, Power-Limiting Breakdown Effects in GaAs MESFET's, 28 IEEE Tr.Elec.Dev. 962 (1982) which demonstrates a good approximation for the breakdown voltage is: ##EQU2## where N(y) is the doping density as a function of depth in the channel and the integration is over the channel thickness. But total charge in the depletion layer at pinch-off is proportional to the maximum current (presuming no charge accumulation):
ƒN(y)dy≈I.sub.max.
Thus I max is inversely proportional to V b : ##EQU3## and the output power per unit gate width of a MESFET is: ##EQU4## Therefore, the power of a standard MESFET is limited by the relationship between V b and I max .
The output power of GaAs FETs can be improved by using insulated gates to increase either V b or I max without decreasing the other. Such metal insulator semiconductor FETs are called MISFETs. Breakdown occurs at the drain-side edge of the gate where the electric field is greatest and involves avalanche multiplication, and for MISFETs the breakdown voltage in this region is very high due to the wide bandgap of the insulator. However, fabrication of MISFETs from GaAs and other III-V compound semiconductors has proved difficult due to the large interface state densities at the insulator-channel interface; see, for example, T. Mimura et al, GaAs Microwave MOSFET's, 25 IEEE Tr.Elec.Dev. 573 (1978) which grows native oxides on GaAs to form MOSFETs; and B. Pruniaux et al, A Semi-Insulated Gate Gallium-Arsenide Field-Effect Transistor, 19 IEEE Tr.Elec.Dev. 672 (1972) which ion implants argon into GaAs to form a semi-insulating layer to act as a gate insulator. These approaches have not been fruitful.
A different approach to III-V MISFETs appears in J. Baranrd et al, Double Heterostructure Ga 0 .47 In 0 .53 As MESFETs with Submicron Gates, 1 IEEE Elec.Dev.Lett. 174 (1980) which uses an undoped AlInAs gate "insulator" on an n type GaInAs channel together with an undoped AlInAs barrier under the channel to confine electrons to the channel. The AlInAs insulator forms a lattice-matched heterojunction with the GaInAs channel and consequently has low interface state densities; but this device has insufficient power handling and the donors in the GaInAs channel scatter the conduction electrons. Also see B. Kim et al, Microwave Power GaAs MISFET's with Undoped AlGaAs as An Insulator, 5 IEEE Elec.Dev.Lett. 494 (1984) which uses an undoped Al x Ga 1-x As gate insulator on a GaAs channel doped n type to a carrier concentration of about 3.5×10 17 /cm 3 .
Another approach is the high electron mobility transistor (HEMT) or modulation doped field effect transistor (MODFET) which typically has an n type Al x Ga 1-x As gate insulator layer epitaxially grown on and forming a heterojunction with an undoped GaAs channel; the donated electrons migrate from the Al x Ga 1-x As into the GaAs due to the conduction band discontinuity and form a two-dimensional electron gas (2DEG) at the interface. The 2DEG provides very high mobility electrons but little power handling capability due to low current levels and a low breakdown voltage of n type Al x Ga 1-x As. Donors in the Al x Ga 1-x As gate insulator screen the gate voltage, and forward bias leads to parallel conduction in the gate insulator and low transconductance. Enhancements such as two n type Al x Ga 1-x As layers, one on either side of the undoped GaAs channel, to provide two interfaces each with a 2DEG do not solve the problems; see S. Judaprawira et al, Modulation-doped MBE GaAs/nAl x Ga 1-x As MESFETs, 2 IEEE Elec.Dev.Lett. 14 (1981). Similarly, Delagebeaudeuf et al, U.S. Pat. No. 4,455,564, combines a MESFET with a HEMT to have a metal gate on a thin heavily doped GaAs channel which is on a thin undoped GaAs second channel which in turn is on a heavily doped Al x Ga 1-x As layer to form a 2DEG in the second channel does not solve the problems. And the heterostructure insulated gate field effect transistor (HIGFET), which has a gate on an undoped Al x Ga 1-x As insulator which is on an undoped GaAs channel and relies on gate bias to induce a 2DEG, does not have high power handling capability and is typically a lower power, digital device; see N. Cirillo et al, Complementary Heterostructure Insulated Gate Field Effect Transistors (HIGFETs), 1985 IEEE IEDM Digest. p. 317.
Thus there is a problem to provide a FET structure with high power handling capablities, high breakdown voltage, and high transconductance at microwave frequencies.
SUMMARY OF THE INVENTION
The present invention provides heterojunction MISFETs which can accumulate charge in the channel under forward bias by use of a second doped heterojunction barrier bounding the channel opposite the insulator. In preferred embodiments the channel is undoped GaAs or InGaAs, the insulator is undoped Al x Ga 1-x As, and the heterojunction barrier is n type Al y Ga 1-y As. The gate length and channel thickness may be adjusted to determine cutoff frequency. The breakdown voltage is not decreased by such accumulation of carriers under forward bias because breakdown relates to reverse bias depletion layer avalanche multiplication, but the maximum current is increased by the accumulated carriers. Additional maximum current is provided by a GaAs active layer opposite the doped Al x Ga 1-x As barrier to form a second parallel channel. A part of this active layer may be doped to provide further power handling.
The accumulation of channel carriers under forward bias solves the problem of limited power handling in microwave FETs by increasing the maximum current without degrading the reverse bias breakdown voltage of a MISFET.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings are schematic for clarity.
FIG. 1 is a cross sectional elevation view of a first preferred embodiment MISFET;
FIGS. 2A-C illustrate the conduction and valence bands for the first preferred embodiment under various bias conditions;
FIG. 3 is a cross sectional elevation view of second and third preferred embodiment MISFETs;
FIGS. 4A-D illustrate the conduction band and electron densities for second and third preferred embodiment MISFETs;
FIG. 5 is a cross sectional elevation view of fourth preferred embodiment MISFET;
FIGS. 6A-F illustrate the conduction band edge and electron density for the fourth preferred embodiment MISFET; and
FIGS. 7-8 are cross sectional elevation views of fifth and sixth preferred embodiment MISFETs.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a schematic cross sectional elevation view of a first preferred embodiment MISFET, generally denoted by reference numeral 30, which includes semi-insulating GaAs substrate 32, 1 μm thick undoped GaAs buffer layer 34, 300 Å thick n type GaAs active layer 36, 100 Å thick n type Al x Ga 1-x As layer 38 which is compositionally graded from GaAs to Al 0 .25 Ga 0 .75 As, 150 Å thick n type Al 0 .25 Ga 0 .75 As barrier layer 40, 150 Å thick undoped GaAs channel layer 42, 100 Å thick undoped Al 0 .5 Ga 0 .5 As insulator layer 44, 0.25 μm long titanium gate 46, 150 Å thick n + type GaAs source and drain contacts 48, gold:germanium/nickel/gold ohmic source and drain contacts 50, and n + doped source and drain regions 52 extending through layers 36, 38, 40, 42, 44, and 48; regions 52 are indicated by the broken lines. Channel 54 is the portion of channel layer 42 between the doped regions 52 and is about 1.0 μm long.
The operation of MISFET 30 can be understood by consideration of the band diagrams of FIGS. 2A-C illustrating the conduction and valence band edges along line 2--2 of FIG. 1 in the depletion, equilibrium, and accumulation states, respectively, which correspond to reverse, zero, and forward biases on gate 46, respectively. Note that if insulator layer 44 were doped, then it would screen gate 46 and limit control by gate 46 of the electron density in channel 54 and active layer 36, and at forward bias parallel conduction through the insulator layer could occur due to the curvature of the band edges. Insulator layer 44 and barrier layer 40 may be different materials provided that each has wider bandgap than the channel layer 42 material, and channel layer 42 and active layer 36 may be different materials provided that each has a narrower bandgap than the barrier layer 40 material.
As illustrated in FIG. 2B, at zero gate bias a two dimensional electron gas (2DEG) forms in GaAs channel 54 at the interface with Al 0 .25 Ga 0 .75 As barrier layer 40; the electrons for the 2DEG are provided by donors in layer 40 and diffuse into and are trapped in channel 54 due to the conduction band discontinuity. Also active layer 36 has a significant electron density due to the high doping (above 3×10 17 /cm 3 ) and little depletion.
A negative (reverse) gate bias of about -1.5 V depletes channel 54 and the 2DEG disappears; see FIG. 2A. Both the undoped insulator layer 44 and the undoped channel 54 act as insulators during reverse bias, and the breakdown voltage V b is thus high. This reverse bias also effectively depletes active layer 36.
Conversely, a forward gate bias of above about +1.0 V leads to accumulation of electrons in the quantum well formed by channel 54 between the two heterojunctions with insulator 44 and barrier 40; note that a significant portion of these accumulating electrons come from the source and drain regions 52. An explicit calculation for the second and third preferred embodiments, infra, will clarify this accumulation effect. Active layer 36 is only slightly depleted at this forward bias; see FIG. 2C. This accumulation at forward bias yields a high maximum current I max .
Further features of MISFET 30 are apparent from the following first preferred embodiment method of fabrication:
(a) Begin with a semi-insulating single crystal GaAs substrate 32 with a planar surface having crystal orientation (100). On the surface grow by molecular beam epitaxy (MBE) successive epitaxial layers of 10,000 Å of undoped GaAs 34, 300 Å of silicon doped GaAs 36 (dopant concentration of 1×10 18 /cm 3 ), 100 Å of silicon doped Al x Ga 1-x As 38 with x varying linearly from 0.0 to 0.25 (dopant concentration about 1×10 18 /cm 3 ), 150 Å of silicon doped Al 0 .25 Ga 0 .75 As 40 (dopant concentration about 1×10 18 /cm 3 ), 150 Å of undoped GaAs 42, 100 Å of undoped Al 0 .5 Ga 0 .5 As 44, and 150 Å of silicon doped GaAs 48 (dopant concentration about 1×10 18 /cm 3 ).
(b) Spin photoresist onto the layered structure from step (a), and pattern source and drain areas 300 μm wide, μm long, and separated by 1.0 μm. Use the pattern photoresist as an etch mask and etch contact layer 48 to form source and drain mesas; note that H 2 O 2 +NH 4 OH or plasma CCl 2 F 2 selectively etch GaAs with respect to Al x Ga 1-x As. Ash the patterned photoresist.
(c) Spin a second photoresist onto the mesa structure from step (b), and pattern openings on the mesas. Use the patterned photoresist as an implant mask and implant silicon (dose about 1×10 12 /cm 2 ) to form n + regions 52 extending through layers 48, 44, 42, 40, and 38 into layer 36 (a total distance of about 700 Å). Then use the same patterned photoresist to deposit gold:germanium/nickel/gold ohmic contacts 50 by liftoff.
(d) Spin on PMMA and pattern a 1 μm long and 300 μm wide opening between the source and drain mesas 48 by electron beam. Use the patterned PMMA to deposit titanium gate 46 by liftoff. Lastly, alloy the ohmic contacts.
Second and third preferred embodiment MISFETs are variants of MISFET 130 shown in cross sectional elevation view in FIG. 3 and include semi-insulating GaAs substrate 132, 10,000 Å thick undoped GaAs active layer 136, 300 Å thick Al 0 .25 Ga 0 .75 As barrier layer 140 which is doped n type to a donor density of 1.5×10 18 /cm 3 , 150 Å thick undoped channel layer 142 which is GaAs in the second preferred embodiment and In 0 .25 Ga 0 .75 As in the third preferred embodiment, 200 Å thick undoped Al 0 .5 Ga 0 .5 As gate insulator layer 144, titanium/platinum/gold gate 146, silicon dioxide dielectric 148, n + source region 150, n + drain region 152, and germanium:gold/nickel/gold source ohmic contact 156 and drain ohmic contact 158. Source region 150 and drain region 152 are formed by implanting silicon into layers 136, 140, 142, and 144 (a total distance of about 800 Å). Note that gate 146 is offset towards source 150 to minimize gate-to-drain capacitance and is "T" shaped to lower gate resistance, and that In 0 .25 Ga 0 .75 As 142 forms a strained layer quantum well between barrier layer 140 and gate insulator layer 144.
FIGS. 4A-D show the calculated conduction band edge and electron density (in terms of electrons per square cm as viewed from a direction perpendicular to the plane of the layers) of MISFET 130 with a forward bias of 0.95 volt in addition to a presumed built-in Schottky barrier of 1.0 volt. These are static Fermi screening calculations for 300° K. With the second preferred embodiment (GaAs channel) FIG. 4A illustrates the conduction band edge and FIG. 4B illustrates the corresponding electron density. The electron density averaged over each layer is as follows:
______________________________________ Electron densityLayer (10.sup.12 /cm.sup.2)______________________________________AlGaAs 144 nilGaAs 142 2.67AlGaAs 140 1.26GaAs 136 1.61Total 5.54______________________________________
Note that the doping of Al 0 .25 Ga 0 .75 As barrier layer 140 at 1.5×10 18 /cm 3 translates to a density of 4.5×10 12 /cm 2 for the 300 Å thick layer. Hence, the total electron density (5.54×10 12 /cm 2 ) under 0.95 volt forward bias shows a 23% increase over the original doping density (which was all in the AlGaAs barrier layer 140), and even higher density can be achieved by higher forward bias through the insulator layer.
Third preferred embodiment MISFET 130 (InGaAs channel) has similar results; see FIGS. 4C and D for the conduction band edge and electron density with a forward gate bias of 0.95 volts. The electron density averaged over each layer is as follows:
______________________________________ Electron densityLayer (10.sup.12 /cm.sup.2)______________________________________AlGaAs 144 nilInGaAs 142 4.13AlGaAs 140 0.50GaAs 136 1.55Total 6.18______________________________________
This accumulation at 0.95 volt forward bias is a 37% increase over the original doping of AlGaAs barrier layer 140. Also, a greater fraction of the electrons are in channel 142 in the third preferred embodiment than in the second preferred embodiment: this is due to the greater heterojunction conduction band discontinuity with InGaAs than with GaAs which yields a deeper quantum well. Hence, using Al x Ga 1-x As with x>0.25 for barrier 140 would further improve the fraction of electrons in channel 142, but heavily doping Al x Ga 1-x As is difficult for x>0.25.
A comparison with the typical doped channel microwave MESFET may be made by noting a channel thickness of 600 Å and doping concentration of 5×10 17 /cm 3 (typical for 0.25 μm long gate MESFET) yields a total charge density at forward bias (no depletion) of 3.0×10 12 /cm 2 . Thus the accumulation in channel 142 provides high total charge for a large I max but without donor ions for scattering.
A fourth preferred embodiment MISFET 180, illustrated in schematic cross sectional elevation view in FIG. 5, includes semi-insulating GaAs substrate 182, 10,000 Å thick undoped Al x Ga 1-x As layer 186 which is graded from x=0 to x=0.25, 1,000 Å thick Al 0 .25 Ga 0 .75 As layer 188 which is undoped, 50 Å thick Al 0 .25 Ga 0 .75 As barrier layer 190 which is doped n type to a donor density of 3.0×10 18 /cm 3 , 150 Å undoped In 0 .25 Ga 0 .75 As channel layer 192, 200 Å thick undoped Al 0 .5 Ga 0 .5 As gate insulator layer 194, titanium/platinum/gold gate 196, n + source region 200, n + drain region 202, and germanium:gold/nickel/gold source ohmic contact 206 and drain ohmic contact 208. Source region 200 and drain region 202 are formed by implanting silicon into layers 190, 192, and 194 (a total distance of about 400 Å). In 0 .25 Ga 0 .75 As channel 192 forms a strained layer quantum well between barrier layer 190 and gate insulator layer 194.
FIGS. 6A-F show the 300° K. static Fermi screening calculated conduction band edge and electron density (in terms of electrons per square cm as viewed from a direction perpendicular to the plane of the layers) of MISFET 180 with a forward bias of 0.95 volt, no bias, and a (reverse) bias of -1.0 volt (all biases are in addition to a presumed built-in Schottky barrier of 1.0 volt). As is apparent from the Figures. MISFET 180 conducts only in channel 192 (no additional active layer analogous to layer 36 of MISFET 30 or layer 136 of MISFET 130) and has a channel and gate insulator similar to those of the third preferred embodiment MISFET 130 but with a narrower doped barrier (and fewer total dopants). In particular, FIGS. 6A-B illustrate the conduction band edge and electron density for a forward bias of 0.95 volt; the electron density averaged over each layer is as follows:
______________________________________ Electron densityLayer (10.sup.12 /cm.sup.2)______________________________________AlGaAs 194 nilInGaAs 192 3.18AlGaAs 190 nilAlGaAs 188 nilTotal 3.18______________________________________
This accumulation is a 112% increase over the original doping of AlGaAs barrier 190 (the original doping was 1.5×10 12 /cm 2 ).
FIGS. 6C-D are the corresponding conduction band edge and electron density for a zero bias; the averaged electron density is:
______________________________________ Electron densityLayer (10.sup.12 /cm.sup.2)______________________________________AlGaAs 194 nilInGaAs 192 0.71AlGaAs 190 nilAlGaAs 188 nilTotal 0.71______________________________________
Lastly, FIGS. 6E-F are the corresponding conduction band edge and electron density for a (reverse) bias of -1.0 volt; the electron density is more than ten orders of magnitude smaller than for zero bias and does not even appear in the graph.
A fifth preferred embodiment MISFET 230, illustrated in schematic cross sectional elevation view in FIG. 7, is a variant of MISFET 30 with doped graded layer 38 and doped active layer 36 replaced by an undoped GaAs active layer 236 which is 100 Å thick and a second doped Al x Ga 1-x As barrier layer 238. Active layer 236 forms heterojunctions with Al x Ga 1-x As barrier layers 238 and 240 and will have a 2DEG at each interface.
A sixth preferred embodiment MISFET 330, illustrated in schematic cross sectional elevation view in FIG. 8, is a variant of MISFET 30 with second doped Al x Ga 1-x As barrier layer 338 and doped graded Al x Ga 1-x As layer 340 for doped GaAs active layer 336.
MODIFICATIONS AND ADVANTAGES
Various modifications of the preferred embodiment devices and methods may be made while retaining the features of a heterojunction MISFET with a second heterojunction doped barrier for accumulating channel carriers under forward bias but with depleting under reverse bias. For example, the dimensions and shapes may be varied such as interdigitated source, gate, and drain fingers, travelling wave transistor configuration, and vertical channel. Also, the materials may be varied such as GaAs-on-silicon or InP substrate, HgCdTe and CdTe layers, AlInGaAsP and GaAsP layers, and superlattices of AlAs and GaAs or other materials and with graded composition of layers or strained layer superlattices. Further, the doping levels may be varied such as light doping (less than 1×10 15 /cm 3 ) in the channel, graded doping in the barrier or active layers (if any), or undoped buffer layers between the barrier and channel or between the barrier and the active layer. In fact, light doping in the gate insulator is also possible, and the dopings of the various layers may be of both conductivity types; however, the barrier and the active layer (if there is one) must be of the same conductivity type for the gate to control both conduction paths. Also, all p doping with two-dimensional hole gasses may be used with all of the embodiments and variations.
The preferred embodiments have the advantages of high breakdown voltage by use of a widegap gate insulator; high mobility conduction carriers by use of an undoped or very lightly doped channel which lattice matches the insulator and a lattice matched barrier layer which provides modulation doping; large maximum current by accumulation of carriers in the channel under forward bias with high transconductance by limiting conduction in the gate insulator by use of an undoped gate insulator; and high frequency operation by short gates and thin channels.
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Preferred embodiments include a microwave power MISFET (30) with a thin GaAS channel (54) bounded by an undoped Al x Ga 1-x As gate insulator (44) and a doped Al y Ga 1-y As barrier (40). Under forward bias the channel (54) forms a quantum well which accumulates electrons and thereby increase maximum current and power handling without degrading breakdown voltage of the heterostructure MISFET An additional active layer (36) can be included on the other side of the barrier (40) to further increase power handling. Other embodiments include use of a strained layer In z Ga 1-z As channel.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 12/244,727 filed on Oct. 2, 2008, which is a continuation U.S. patent application Ser. No. 09/295,577 filed on Apr. 22, 1999, now U.S. Pat. No. 7,454,361, the disclosures of which are hereby incorporated by reference in their entirety.
BACKGROUND
1. Field of the Invention
This invention relates to an electronic means by which people can select the exact seat or seats they want for any type of event or reserve an appointment for any activity such as a doctor or dentist appointment or even an appointment to have their car lubed. More specifically, a customer or a ticket re-seller or a venue operator can go, for example, to the internet and select the event or activity for which they want a ticket or tickets or reserve a time and reserve and order the exact seat or seats or the time of their choosing directly online. The seat or seats or reserved time they select is then removed from the inventory for that activity or event and made not available for any other buyer and such is so indicated by a graphical representation or other such indicator on the online map or picture representing availability of seating or time for that event. For an appointment reservation, the user connects to the internet or other wide area network, such as a bulletin board, from his home of office computer and connects to a page that displays a reservation calendar where he can interact such as to reserve a specific time period for himself.
In accordance with the present invention a remote location ticketing and reservation system for any venue comprises an internet or network compatible computer program constructed generally to afford access to a database, or other record maintained in electronic form, containing information about all sold and unsold seating for any specific venue or event and means and method by which a remote user, through use of a computer terminal or other such device, may access said database or other record and receive at his location through any computer terminal or other such device information about which specific seats remain available and then through a computer mouse or keyboard or other such input device select a specific seat or seats for that specific event and reserve such for himself for use during said event.
2. Prior Art
The inadequacies and inefficiencies of present ticketing and reservation systems are recognized and addressed through this invention. The rapid growth of the internet now makes it possible for anyone at his home or office to avail himself of the advantages of the instant invention through a simple internet or other wide area network connection.
Prior art makes a feeble attempt to address the inconvenience of ticket ordering. U.S. Pat. No. 5,797,126 (1988), Helbling, et al., describes a series of individual kiosks in wireless communication with a central station where a visitor can locate events of interest, view an excerpt of scenes from that venue and purchase tickets. This falls far short of the instant invention since it still requires a user to physically visit a remote site to avail himself of the service. Additionally, said prior art makes extensive use of what is called “kiosks” implying that, unlike the instant invention, it is only from his specialized machines that such services may be rendered.
U.S. Pat. No. 4,974,252 describes a more interactive theater attendance system where patrons are permitted two way communications between themselves and a broadcast center but this is still far from objectives of the instant invention and requires that persons be in attendance at the theater and, further some attendant be present at the remote broadcast center. The instant invention is fully automated and, other than the normal monitoring of any application for a wide area network, requires no human attendance or intervention.
U.S. Pat. No. 3,427,438 describes a ticket vending system where sales of tickets can be recorded on a seating layout but, again falls far short of the instantaneous update and automatic operation of the instant invention. U.S. Pat. No. 5,333,257 allows for a view from a seat but that is now common for internet applications where a hyperlink to any graphic is routinely provided and ancillary to and even unnecessary to the instant invention. Other prior art does nothing to make ticket ordering or seating reservations more readily available and does nothing to improve the information flow to prospective customers so that they may make a more informed decision about attending any given event.
Consider the traveler who has planned a vacation in, say, New York City and wants tickets for some Broadway show. Presently he has either to phone and accept someone else's definition of what constitutes “best available” or wait until he gets into town and seek out a scalper or reseller agency and he still isn't sure exactly what his seats offer.
OBJECTS AND ADVANTAGES
Several objects and advantages of the present invention are:
(a) to always provide customers with a seat selection comprised of the total of the then best available seats for any given event; (b) to make equally available to all customers all then available seats for any given event to that said customer, so he may select for himself the seat or seats he wants for that event; (c) to provide an alternative means to visiting box office or a ticket reseller for a customer to select and reserve for himself the then best available seat or seats for any arena, stadium, theater, airline flight or any other such venue where seating is available; (d) to provide to a ticket sensitive venue operator better control over the seating and seat availability for the various events he offers; (e) to provide to a ticket sensitive venue operator better accounting of his seating for the various events he offers; (f) to provide to the general public a more cost effective means by which he may reserve and buy tickets for any given event; (g) to provide to a venue operator a more cost effective means by which he may sell tickets for any given event; (h) to provide to the general public an automated 24 hours a day, seven days a week means by which he may reserve and purchase the specific seats he wants for an event; (i) to provide to a venue operator an automated 24 hours a day, seven days a week means by which he may offer reservation and purchase of a seat or seats that are individually selectable by a customer; (j) to permit the venue operator to avoid overbooking an event; (k) to permit the venue operator to avoid underbooking an event; (l) to permit a doctor or other professional for whom his time is a commodity to better schedule and regulate his time and interact with patients or others in the online environment; (m) to provide to the general public a 24 hours a day, seven days a week means by which they may schedule appointments with doctors, dentists, automotive mechanics and the like with full knowledge that the appointment time they select is still available.
Further objects and advantages are to provide any venue operator the benefit of better control over his ticket inventory and sales such as to improve his profitability and the efficiency of his operation and to provide to the general ticket buying public better information and an easier means by which they may acquire their desired ticket or tickets for any event.
SUMMARY OF THE INVENTION
The ticketing and reservation system of the present invention, in one particular embodiment thereof, includes a computer program operating on a server for a wide area network (WAN), generally described by the flow chart of FIG. 1 and the accompanying code example which implements the instant invention in practice:
First, when a user accesses the system means is provided to initialize the process and return to the user a menu from which he selects his venue of interest. This can be a selectable menu arranged by artist or date or time or specific theater or football team or baseball team or name or activity or any combination thereof such that the user is given sufficient information from which to make a decision. An example would be someone looking for the next event at a given theater at a time that starts at 7:00 pm. One of many possible series of computer instructions to perform this function is:
<-Send database query to retrieve all venues that are currently available in the system-> <-Server receives and processes query-> <-Query is looped until all available performances and venues are retrieved-> <-Markup Language engine converts result to display compatible format for output to client computer-> <-Begin normal markup language here-> <-Begin reservation process selecting the event date/time next to the desired venue->
THEN, upon user submittal, the server initializes the process of returning to the user all available seats:
<-Send database query to retrieve all seats that are currently available in the system for this event-> <-Server receives and processes query-> <-Query is looped until all available seats are retrieved-> <-Markup language engine converts result to markup language format for output to client computer-> <-Begin normal markup language here-> <-Continue reservation process by selecting the desired seat or seats->
THEN, upon user submittal we create a new customer record in the Wide Area Network server and tell the system which database to connect to to fulfill the user's request(s):
<-Send database command to insert new record in customer database and obtain record id-> <-Send database command to insert new record in reservation “order” database and obtain record id-> <-Send database command to insert new record for each selected seat in the reservation “detail” database-> <-Begin normal markup language here-> <-Continue reservation process by requesting client payment information->
THEN, upon user submittal the information is passed for verification:
<-Submit client information for verification-> <-If verification is successful, send database command to update customer record in customer database with information previously collected-> <-If verification is successful, send database command to update reservation record in reservation “order” database with verification information-> <-If verification is successful, send database command to remove selected seats from seat inventory database and mark as no longer available for future selection-> <-Markup language engine converts result to markup language format for output to client computer-> <-Begin normal markup language here-> <-If verification is successful, confirmation is generated via Markup language engine to markup language format for output to client computer-> <-If verification is unsuccessful, a failure notice is generated via Markup language engine to markup language format for output to client computer-> <-If verification is unsuccessful, client is presented with option to provide his payment information again or abandon his reservation->
While this is one preferred form of the code there are many other code sequences that will perform the same function that will be immediately obvious to one skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
The aforementioned objects and advantages of the present invention as well as additional objects and advantages thereof will be more fully understood hereinafter as a result of a detailed description of a preferred embodiment when taken in conjunction with the following drawings in which:
FIG. 1 is a block diagram of the present invention illustrating the major components thereof and the interactivity that takes place between the potential customer and the instant invention.
FIG. 2 is an illustration of the concept of the present invention utilizing the internet as the Wide Area Network to which users connect to perform the desired function and shows an example of a remotely located user accessing the functionality of the instant invention for purposes of reserving seats for a dinner theater performance in a distant city.
FIGS. 3A and 3B are illustrations of the concept of the present invention refined down to the functionality of reserving specific seats and blocking duplicate sale of those seats that are already reserved.
FIGS. 4A to 4E are sample screens seen by a remote user of the instant invention during a session wherein he selects and orders four specific seats for a distant dinner theater show.
FIG. 5 is a complete code set for one preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , it will be seen that the operator of a venue implements the instant invention for purposes of allowing remotely located users to reserve specific seating for specific events 1 . By doing so, he initiates those certain actions necessary to display an internet web site to all online users 2 . A prospective customer for the venues offering(s) logs onto the internet 3 and acquires the aforesaid internet web site 4 which implements the instant invention. He can be connected to the internet by any conventional means yet this by no means implies that the wide area network must be what is commonly referred to as the “internet.” Upon first contact by the prospective customer, an inquiry is directed to the appropriate database, which may be located concurrent with the primary server hosting the program for the instant invention or may be located remotely, such as at the physical location of the venue, asking for a return of information to the prospective customer of all appropriate information contained therein relative to his inquiry 5 . The prospective customer indicates his desired seat or seats through conventional computer input means and directs that information back to the server hosting the code necessary to the implementation of the instant invention 6 . Upon contact 7 the server again makes an appropriate database query and returns to the prospective customer all pertinent information relating to his selection, such as which seats are still available for the chosen performance, airline flight, boxing match, etc. The prospective customer is then presented with a representation of all then available seating for his selected venue 8 . From this representation, the prospective customer makes his selection of a seat or seats by indicating such through a mouse click, keyboard entry or other means, such as but not limited to a touch screen. Simultaneously, the server, through the coding necessary to implement the instant invention, creates a temporary customer identification 9 that is used to associate this potential customer with this later selection and permit system use by multiple simultaneous users. Once the customer has made his seat selection he is asked for payment information 10 . That information is processed through conventional internet or other electronic means and once the information and payment are verified 11 a the customer information, as supplied in 10 , is made permanent and the seat or seats he has selected are removed from inventory and blocked from duplicate sale, both graphically when presented to the next prospective customer and in the database where information for accounting and administrative purposes is retained. If the customer's payment information cannot be verified 11 b then he is given an opportunity to correct the information or start over with a new transaction. Upon verification of the customer's payment information he receives a confirmation of the transaction 13 containing all appropriate reference information for his records.
Referring to FIG. 2 , it will be seen that, for example, a user in Houston 13 is planning to vacation in New York and wishes to see a play at a dinner theater there that utilizes the present invention for ticketing and reservations 15 . The user in Houston, or in any other location worldwide, connects to the internet in the conventional way and retrieves the appropriate web site through his graphical browser from a server located in, say, Anaheim, Calif. 14 . Through implementation of the instant invention the user is able to see the exact seating arrangement of the remote dinner theater and select the exact seat or seats he wants for the performance of his choice. Such additional information as is appropriate can be provided to the remote user to assist him in making an informed decision as to which seat or seats he wishes to occupy for this performance.
Referring to FIGS. 3A and 3B , it will be seen that in FIG. 3A that, at the user selected venue, all seats at table P 11 17 and at table S 14 18 have been previously taken and are so indicated by the graphical representation of an “X” over those seats. Our potential customer wants to seat a party of four at table S 1 16 and so indicates by clicking his mouse on those four seats or by so indicating through an alternative standard computer input means. Once his payment method is verified his selected seats are removed from inventory and so indicated on the graphical representation by placing an “X” over those seats 19 while retaining the “X” over those seats previously sold at table P 11 20 and table S 14 21 . The next prospective customer is advised that these seats are no longer available for this performance by the new graphical representation shown in FIG. 3B that is his first viewing screen upon entry into the system. In the event that two prospective customers wish to reserve the exact same seat or seats, that prospective customer who first receives validation of his payment method is given those seats while the other prospective customer is notified that while making his decision the seats he wants have already been sold and offers him a chance to select other seating.
Referring to FIGS. 4A to 4E , one will see the screens presented to a user when he accesses the system and as he progresses through the process of selecting a specific seat or seats, then reserves and pays for them. FIG. 4A is where the first screen presented shows links to available performances for that selected venue 22 . FIG. 4B is the second screen 23 and shows a view of the seating available for that venue with seats that have already been taken crossed off with an “X” 24 . Our hypothetical user decides that he would like to have his party of four sit at table S 11 25 and selects the four seats around that table by clicking on them with his mouse. As he moves his mouse over individual seats the seat number appears in the window at the bottom of his screen 26 and when he clicks on a seat it is added to a running tally of the seats he has already taken 27 . Only seats that have not previously been taken show up in the mouse-over window 26 . After completing his selections the user clicks on the “Reserve Seats” button and FIG. 4C shows his next screen, which asks him for his payment information 28 . He enters the required information and again clicks the “Reserve Seats” button 29 . FIG. 4D is the next screen and it tells him that his payment method has been accepted (or rejected) and relates information about the transaction 30 such as his transaction code and the receipt number that he can use as a ticket or as a voucher with which to redeem his ticket or tickets at the venue box office when he arrives for the performance. Finally, FIG. 4E shows the opening screen the next visitor to the system is presented with the same set of screens except that the seats reserved by our hypothetical user 31 are marked off as already taken.
Referring to FIG. 5 , one will see one of many possible coding schemes making possible the results of the present invention.
Those having skill in the art to which the present invention pertains will now understand that there are virtually unlimited uses for the present invention. By way of example, the present invention may be readily used to reserve specific seats on commercial airliners or reserve specific staterooms on a cruise ship, as well as for reserving seats for any venue from community theater or little league baseball to major league sporting events.
The present invention has been described in sufficient detail to enable one skilled in the art to make and use the invention. Accordingly, specific details which are readily available in the art or otherwise conventional have been omitted to prevent obfuscation of the essential features of the invention.
In view of the foregoing it will be understood that the present invention may be implemented in a variety of alternative methods but that all such implementations are deemed to be within the scope of the present invention which is to be limited only by the claims appended hereto:
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The present invention relates to a system and method for selecting and reserving seats using a touch screen device. The system or method transmits first data to an application running on a personal computing device, the first data including information descriptive of available individual seats at the venue, the first data processed by the application to generate a graphical user interface on the personal computing device that comprises an interactive seating map representing individual seats at the venue. The system or method also receives from the personal computing device second data representing one or more seats selected by a touch screen input. In addition, the system or method receives over the network from the personal computing device third data representing payment information.
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BACKGROUND
1. Field of Invention
The present invention relates generally to an applicator with fluids sealed within it. More specifically, the present invention relates to an applicator with one or more fluids sealed separately within it with opening means enclosed within the applicator to allow the commingling and releasing of the fluids enclosed within the applicator.
2. Description of Related Art
Applicators such as cotton swabs are generally used to apply medication, anesthetic, alcohol, and various other liquids. Swab applicator generally comprises of a tubular handle with a formed absorbent tip at one or both ends of the tubular handle. The absorbent tip may be made of cotton or a foam absorbent material. The tip may also be a brush. The tubular handle may be made of wood, paper, or plastic and it may be solid or hollow.
Generally the applicator tip of a dry swab applicator is first placed in contact with the liquid to be applied for the applicator tip to absorb the liquid. Subsequently, the moisturized applicator tip is placed in contact with the surface to apply the absorbed liquid to the surface. Swab applicators may also be pre-moistened with the desired liquid and sealed in a container for subsequent use. Generally the pre-moistened swab applicators are packaged individually so that opening the packaging to retrieve one swab applicator will not affect the remaining swab applicators.
SUMMARY OF THE INVENTION
The present invention is a multi-fluid applicator with one or more fluids sealed separately within it with opening means enclosed within the applicator to allow the commingling and releasing of the fluids enclosed within the applicator. The enclosed opening means may be operated by bending the applicator at or near the enclosed opening means. Once the enclosed opening means is opened, the fluids sealed within the elongated sealed container will commingle with each other and be released for application or may be released directly for application. There are no loose parts that may be lost and the fluids are completely sealed within the applicator.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a cross-sectional view of the preferred embodiment of the multi-fluid applicator.
FIG. 2 shows a cross-sectional view of another embodiment of the multi-fluid applicator.
FIG. 3 shows a cross-sectional view of another embodiment of the multi-fluid applicator.
FIG. 4 shows a cross-sectional view of another embodiment of the multi-fluid applicator.
FIG. 5 shows a cross-sectional view of another embodiment of the multi-fluid applicator.
FIG. 6 shows a cross-sectional view of another embodiment of the multi-fluid applicator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a cross-sectional view of the preferred embodiment of the multi-fluid applicator. In the preferred embodiment, the multi-fluid applicator comprises of a first elongated tubular housing 1 with a sealed end 2 and an open end 3 . A first fluid 4 is enclosed within the first elongated tubular housing 1 .
A second elongated tubular housing 5 with a sealed end 6 and an open end 7 and with approximately the same outside diameter at a location near its sealed end 6 as the open end 3 of the first elongated tubular housing 1 is inserted with its sealed end 6 inside the open end 3 of the first elongated tubular housing 1 sealing the first fluid 4 within the first elongated tubular housing 1 . A second fluid 8 is enclosed within the second elongated tubular housing 5 . The second fluid 8 may be the same as or different than the first fluid 4 . An opening means 9 in the form of a fracture line is located near the sealed end 6 of the second elongated tubular housing 5 and positioned within the first elongated tubular housing 1 such that the sealed end 6 of the second elongated tubular housing 5 will sever from the remainder of the second elongated tubular housing 5 when the elongated tubular housings 1 , 5 are bent near the fracture line to allow the first fluid 4 in the first elongated tubular housing 1 to commingle with the second fluid 8 in the second elongated tubular housing 5 .
A viscous substance 10 such as silicone may be disposed near the open end 7 of the second elongated tubular housing 5 to seal the second fluid 8 within the second elongated tubular housing 5 and to prevent evaporation of the second fluid 8 . After the opening means 9 is opened, the first fluid 4 will commingle with the second fluid 8 and the two fluids 4 , 8 may be ejected from the applicator by squeezing the first elongated tubular housing 1 for application. An applicator tip 11 such as a cotton or foam swab or a brush may be affixed to the open end 7 of the second elongated tubular housing 5 to apply the ejected fluids 4 , 8 .
The open end 7 of the second elongated tubular housing 5 may also be sealed and provided with a second opening means such as a fracture line to allow complete sealing of the second fluid in the second elongated tubular housing 5 . After the opening means 9 is opened, the first fluid 4 will commingle with the second fluid 8 and the two fluids 4 , 8 may be ejected from the applicator by opening the second opening means and then squeezing the first elongated tubular housing 1 for application.
The first fluid 4 may also be omitted with the first elongated tubular housing 1 simply filled with a gas, such as air. The fluid sealed in the second elongated tubular housing 5 may be controllably released by first opening the opening means and then squeezing the first elongated tubular housing 1 . The rate and amount of the fluid extracted may be controlled by the pressure applied to the first elongated tubular housing 1 .
Furthermore, one of the fluids, such as the first fluid 4 , may also be replaced with a powder substance wherein when the opening means 9 is opened the fluid in the applicator will mix with the powder substance and subsequently be ejected for application. This is particularly suitable when the application requires that a powder substance be kept dry until application, at which time the dry powder must be mixed with a fluid such as an activating agent.
Another embodiment of the multi-fluid applicator is shown in FIG. 2 . In this embodiment, the multi-fluid applicator comprises of an elongated tubular housing 21 with a sealed end 22 and an open end 23 . A restriction 24 is disposed between the sealed end 22 and the open end 23 generally separating the elongated tubular housing 21 into two sections. A first fluid 25 is enclosed within the first section near the sealed end 22 of the elongated tubular housing 21 . A second fluid 26 is enclosed within the second section near the open end 23 of the elongated tubular housing 21 . The second fluid 26 may be the same as or different than the first fluid 25 .
A first opening means in the form of a first elongated tube 27 with a sealed end 29 and an open end 30 and with approximately the same outside diameter as the restriction 24 of the elongated tubular housing 21 is inserted with its sealed end 29 inside the restriction 24 in the elongated tubular housing 21 sealing the first fluid 25 within the elongated tubular housing 21 . A fracture line 28 is located near the sealed end 29 of the first elongated tube 27 such that the sealed end 29 of the first elongated tube 27 will sever from the remainder of the first elongated tube 27 when the elongated tubular housing 21 and the first elongated tube 27 are bent near the fracture line 28 .
A second opening means in the form of a second elongated tube 31 with a sealed end 32 and an open end 33 and with approximately the same outside diameter at a location near its sealed end 32 as the open end 23 of the elongated tubular housing 21 is inserted with its sealed end 32 inside the open end 23 of the elongated tubular housing 21 sealing the second fluid 26 within the second section of the elongated tubular housing 21 . A fracture line 34 is located near the sealed end 32 of the second elongated tube 31 such that the sealed end 32 of the second elongated tube 31 will sever from the remainder of the second elongated tube 31 when the elongated tubular housing 21 and the second elongated tube 31 are bent near the fracture line 34 .
After the first opening means is opened, the first fluid 25 will commingle with the second fluid 26 . The second opening means may subsequently be opened to allow extraction of the fluids 25 , 26 from the applicator by squeezing the elongated tubular housing 21 for application. An applicator tip 35 such as a cotton or foam swab or a brush may be affixed to the open end 33 of the second elongated tube 31 to apply the extracted fluids 25 , 26 .
One of the fluids, such as the first fluid 25 , may be replaced with a powder substance wherein when the first opening means is opened the fluid in the applicator will mix with the powder substance and subsequently be ejected for application. This is particularly suitable when the application requires that a powder substance be kept dry until application, at which time the dry powder must be mixed with a fluid such as an activating agent.
Yet another embodiment of the multi-fluid applicator is shown in FIG. 3 . In this embodiment, the multi-fluid applicator comprises of an elongated tubular housing 40 with a sealed end 41 and an open end 42 . A restriction 43 is disposed between the sealed end 41 and the open end 42 generally separating the elongated tubular housing 40 into two sections. A first fluid 44 is enclosed within the first section near the sealed end 41 of the elongated tubular housing 40 . A second fluid 45 is enclosed within the second section near the open end 42 of the elongated tubular housing 40 . The second fluid 45 may be the same as or different than the first fluid 44 .
An opening means in the form of an elongated tube 46 with a sealed end 47 and an open end 48 is inserted with its sealed end 47 inside the restriction 43 in the elongated tubular housing 40 sealing the first fluid 44 and the second fluid 45 within the elongated tubular housing 40 and with approximately the same outside diameters located near the restriction 43 and the open end 42 as the restriction 43 and the open end 42 of the elongated tubular housing 40 . A first fracture line 49 is located near the sealed end 47 disposed within the first section and a second fracture line 50 is located near the open end 42 of the elongated tubular housing 40 such that the elongated tube 46 will break open when the elongated tubular housing 40 and the elongated tube 46 are bent near the fracture lines 49 , 50 .
The opening means may be selectively opened to allow the first fluid 44 , the second fluid 45 , or both fluids 44 , 45 to be released from the applicator by squeezing the elongated tubular housing 40 for application. An applicator tip 51 such as a cotton or foam swab or a brush may be affixed to the open end 48 of the elongated tube 46 to apply the extracted fluids 44 , 45 .
Yet another embodiment of the multi-fluid applicator is shown in FIG. 4 . In this embodiment, the multi-fluid applicator comprises of an elongated tubular housing 60 with a sealed end 61 and an open end 62 . A restriction 63 is disposed between the sealed end 61 and the open end 62 generally separating the elongated tubular housing 60 into two sections. A first fluid 64 is enclosed within the first section near the sealed end 61 of the elongated tubular housing 60 . A second fluid 65 is enclosed within the second section near the open end 62 of the elongated tubular housing 60 . The second fluid 65 may be the same as or different than the first fluid 64 .
An opening means in the form of an elongated tube 66 with a sealed, end 67 and an open end 68 is inserted with its sealed end 67 inside the restriction 63 in the elongated tubular housing 60 sealing the first fluid 64 and the second fluid 65 within the elongated tubular housing 60 and with approximately the same outside diameters located near the restriction 63 and the open end 62 as the restriction 63 and the open end 62 of the elongated tubular housing 60 . A first fracture line 69 is located near the sealed end 61 and positioned such that when the elongated tube 66 is inserted inside the restriction 63 the first fracture line 69 will be inside the first section. A second fracture line 70 is located near the first fracture line 69 opposite the restriction 63 . A third fracture line 71 is separated from the first 69 and second 70 fracture lines by a sealed-off section 72 of the elongated tube 66 located near the open end 62 of the elongated tubular housing 60 . A third fluid 73 is enclosed by the sealed-off section 72 of the elongated tube 66 . The third fluid 73 may be the same as or different than the other two fluids 64 , 65 . The elongated tube 66 will break open when the elongated tubular housing 60 and the elongated tube 66 are bent near the fracture lines 63 , 70 , 71 .
The opening means may be opened to allow the three fluids 64 , 65 , 73 to be commingled and released from the applicator by squeezing the elongated tubular housing 60 for application. When the first fracture line 69 is broken, the first fluid 64 will commingle with the third fluid 73 . When the second fracture line 70 is broken, the commingled first 64 and third 73 fluids will commingle with the second fluid 65 . When the third fracture line 71 is broken, the commingled fluids 64 , 65 , 73 will be released from the applicator. An applicator tip 74 such as a cotton or foam swab or a brush may be affixed to the open end 68 of the elongated tube 66 to apply the extracted fluids 64 , 65 , 73 .
One of the fluids, such as the first fluid 64 , may be replaced with a powder substance wherein when the opening means are opened the fluid in the applicator will mix with the powder substance and subsequently be ejected for application. This is particularly suitable when the application requires that a powder substance be kept dry until application, at which time the dry powder must be mixed with a fluid such as an activating agent.
Yet another embodiment of the multi-fluid applicator is shown in FIG. 5 . In this embodiment, the multi-fluid applicator comprises of an elongated tubular housing 80 with a sealed end 81 and an open end 82 . Multiple restrictions 83 are disposed between the sealed end 81 and the open end 82 generally separating the elongated tubular housing 80 into multiple sections. A fluid 84 , 85 , 86 , 87 is enclosed within each of the sections of the elongated tubular housing 80 . The fluids 84 , 85 , 86 , 87 may all be the same fluid or different fluids may be used in each section.
An opening means in the form of an elongated tube 88 with a sealed end 89 and an open end 90 is inserted with its sealed end 89 through all the restrictions 83 in the elongated tubular housing 80 sealing each of the fluids 84 , 85 , 86 , 87 in the respective sections in the elongated tubular housing 80 and with approximately the same outside diameters located near each of the restrictions 83 and the open end 82 as the restrictions 83 and the open end 82 of the elongated tubular housing 80 . A fracture line 91 is located near each of the restrictions 83 disposed within each section such that the fluid 84 , 85 , 86 , 87 within a section will be released when the fracture line 91 in that section is broken open when the elongated tubular housing 80 and the elongated tube 88 are bent near the fracture line 91 .
The opening means may be selectively opened to allow the desired fluid to be released from the applicator by squeezing the section of the elongated tubular housing 80 with the fluid. An applicator tip 92 such as a cotton or foam swab or a brush may be affixed to the open end 90 of the elongated tube 88 to apply the extracted fluid.
Yet another embodiment of the multi-fluid applicator is shown in FIG. 6 . In this embodiment, the multi-fluid applicator comprises of an elongated tubular housing 100 with a sealed end 101 and an open end 102 . Multiple restrictions 103 are disposed between the sealed end 101 and the open end 102 generally separating the elongated tubular housing 100 into multiple sections. A fluid 104 , 105 , 106 , 107 is enclosed within each of the sections of the elongated tubular housing 100 . The fluids 104 , 105 , 106 , 107 may all be the same fluid or different fluids may be used in each section.
An opening means in the form of an elongated tube 108 with a sealed end 109 affixed to the sealed end 101 of the elongated tubular housing 100 and an open end 110 that extends through all the restrictions 103 in the elongated tubular housing 100 sealing each of the fluids 104 , 105 , 106 , 107 in the respective sections in the elongated tubular housing 100 and with approximately the same outside diameters located near each of the restrictions 103 and the open end 102 as the restrictions 103 and the open end 102 of the elongated tubular housing 100 . A fracture line 111 is located near each of the restrictions 103 disposed within each section such that the fluid 104 , 105 , 106 , 107 within a section will be released when the fracture line 111 in that section is broken open when the elongated tubular housing 100 and the elongated tube 108 are bent near the fracture line 111 .
The opening means may be selectively opened to allow the desired fluid to be released from the applicator by squeezing the section of the elongated tubular housing 100 with the fluid. An applicator tip 112 such as a cotton or foam swab or a brush may be affixed to the open end 110 of the elongated tube 108 to apply the extracted fluid.
Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.
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A multi-fluid applicator with one or more fluids sealed separately within it with opening device enclosed within the applicator to allow the commingling and releasing of the fluids enclosed within the applicator. The enclosed opening device may be operated by either squeezing or bending the applicator at or near the enclosed opening device. Once the enclosed opening device is opened, the fluids sealed within the elongated sealed container will commingle with each other and be released for application or may be released directly for application. There are no loose parts that may be lost and the fluids are completely sealed within the applicator.
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FIELD OF THE INVENTION
[0001] The field of the invention relates to chiral ionic liquids (CILs) as novel solvents. In particular the invention relates to CILs for organic synthesis. More particularly, the invention relates to CILs which have the potential to induce asymmetry into substrates or catalysts in a variety of organic transformations. In particular, the invention relates to biodegradable CILs suitable for these applications.
BACKGROUND TO THE INVENTION
[0002] Ionic liquids (ILs) have been used as alternative solvents for a wide range of chemical processes. Over the past decade, while the “greenness” of ILs has been debated, the emergence of industrial processes which make use of ILs to improve their environmental profiles (West) continues to fuel the explosion in research focused on ILs. ILs are of industrial value in the “green” sense, as they possess favourable properties including very low volatility and facile separation of products in suitable cases. This means that ILs have very low vapour pressure and produce virtually no hazardous vapours when compared with traditional volatile solvents. ILs are also attractive as their properties may be tailored or fine-tuned to meet various needs, and ILs now have applications as solvents, chiral coordinating solvents and directing catalysts. ILs now also find uses in applications such as electrochemistry, for example, in wet cell batteries, and also in photochemistry and organic synthesis, as both solvents and as catalysts.
[0003] ILs based on aromatic heterocyclic cations, such as imidazolium and pyridinium cation-based ILs are particularly popular due to their ease of modification, low charge density about the aromatic ring and cation stability under acidic conditions. The low aromatic charge density, in particular, means it is easy to synthesize low melting salts (low melting point being a fundamental property of ILs). Unfortunately, traditional ILs based on N-alkylimidazolium and N-alkylpyridinium cores do not lend themselves to biodegradability. In fact, it is well known that dialkyl substituted imidazoles and unsubstituted N-alkylpyridinium rings have limited biodegradability. Biodegradability can be improved with fuctionalisation of the core sidechain(s). In particular, introduction of ester functionality into the IL is known to improve the overall biodegradability.
[0004] In 2002, Gathergood and Scammells designed environmentally friendly biodegradable achiral ILs, containing side-chains which act as potential sites of enzymatic hydrolysis. Subsequent studies by Gathergood, directed towards the development of biodegradable, low toxicity solvents that have performance advantages over established solvent media indicated that the presence of an ester linkage in the side chain of the IL cation promoted biodegradation. The IL counterion was also a significant factor, with octylsulfate examples proving readily biodegradable. The Gathergood group recently reported that key features which improve biodegradation and reduce antimicrobial toxicity were also required for improved catalyst performance in the selective hydrogenation of phenoxyocta-2,7-diene. Further investigations by Gathergood into changes in conversion and selectivity in the hydrogenation reactions of cinnamaldehydes and benzyl cinnamate using novel biodegradable and/or low toxicity ILs and recycling of the catalyst/IL media resulted in a communication being published in the journal Green Chemistry (Morrissey et al).
[0005] International Patent Application No. PCT/EP2008/060978 describes ionic liquid (IL) solvents for chemical synthesis based on an N-alkylimidazolium cation core which have enhanced biodegradability and reduced toxicity relative to existing imidazolium bases ILs such as 1-butyl-3-methylimidazolium (bmim) salts, many of which produce a score of over 60% biodegradability over 28 days in the Sturm Test, the Closed Bottle Test (OECD 301D) or the CO 2 Headspace Test (ISO 14593).
[0006] Several groups have approached the problem of increasing biodegradability by developing biorenewable ILs based on cheap, readily available molecules from biological molecules that can be sourced from nature and recycled in known biochemical pathways (e.g. Han's choline cations combined with proline carboxylate anion). While these biorenewables are intended to take the place of synthetic quaternary nitrogen cations such as the alkylammonium, dialkylimidazolium and pyridinium components often found in previous generation ILs, it is sometimes the case that a biorenewable molecule, such as choline (derived from lipids and important as an acetate in neurotransmission) is more cheaply available via a synthetic process (choline is prepared commercially from ethylene oxide and trimethylamine via the Davy Process). Research has led to new ILs where cations are derived from alpha-amino acids and alpha-amino acid ester salts. Since amino acids are essentially a ‘food source’, they can be taken up by bacteria, fungi etc., into the usual biochemical pathways where they are degraded. These ILs are particularly advantageous compounds, since stereocentres have been retained in the final IL product (Chen et al).
[0007] However robust, imidazolium-based ILs, which are stable to a wide range of chemical environments (with notable exceptions) and can be accessed by short, simple synthetic routes, still dominate the field.
[0008] The special characteristic that chiral ionic liquids (CILs) possess of being tunable solvents, in which solvent interactions such as polarity, hydrophobicity, and π-π stacking interactions can be tailor-made to an application means that CILs are attracting considerable interest as chiral solvents (Baudequin et al) with many possible applications. Thus, chiral ionic liquids (CILs) are attracting much interest. Solvent chirality is achievable with complex solvents such as ILs. Chirality may be found in either or both of the IL cation and anion.
[0009] Although chiral solvents have been known for many years, their major application has been in NMR detection of enantiomeric excesses in chiral compounds. Since Seebach's landmark discovery of modest asymmetric with a chiral solvent in 1975, only a few examples of asymmetric induction using chiral solvents have appeared. Excessive cost, a paucity of applications and modest performance have limited their usefulness. In 2007, Hüttenhain achieved an optimum enantiomeric excess of only 59% in the reduction of acetophenone to 1-phenylethanol at −78° C. using BH 3 together with ZnCl 2 and (S)-methyl lactate as the solvent, together with a THF co-solvent.
[0010] Earle et al reported a first chiral IL solvent possessing chirality in the anion, comprising [bmim][lactate](bmim=butyl methyl imidazolium), having a chiral anion of (S)-configuration and its use in reaction of dienes and dienophiles. However the products of the reaction were not asymmetric. The [bmim][lactate] ionic liquid was synthesised by the reaction of sodium (S)-2-hydroxypropionate and [bmim]Cl in acetone. The resultant precipitate of sodium chloride was filtered off and the acetone evaporated.
[0000]
[0011] Chinese Patent Application Publication No. 1 749 249 describes a chiral ionic liquid for use as a chiral catalyst and a chiral solvent, the ionic liquid comprising a cation and a chiral lactate anion.
[0012] N-alkylated methyl ephedrine has been used as a chiral cation for ILs in a Baylis-Hillman reaction and chirality was induced in the product. It was proposed that asymmetric induction resulted from the hydroxyl group of methyl ephedrine which could assemble the reagents into a highly ordered transition-state, favouring the desired configuration (Pegot et al).
[0013] United States Patent Publication No. US 2005/0065020 describes ionic liquids which have a secondary hydroxyl group and an atom efficient method for the preparation of these ionic liquids by opening an epoxide with an alkylimidazole in the presence of acid. This procedure leads directly to chiral ILs, where chirality is conferred on the cation. Preferably the ILs contain an N-(2-hydroxyalkyl) substituent to provide compounds of general formula (I*), wherein X represents an anion:
[0000]
[0014] Howarth et al, described [N,N-di(2′S-2′-methylbutane) imidazolium bromide]. This imidazolium ion has two chiral side chains and was used in a catalytic Diels-Alder reaction. The products were produced in minimal enantiomeric excess only. Furthermore, this chiral IL is likely to be expensive to make in an optically enhanced form, since the synthesis requires an optically enhanced bromide compound or alternative alkylating agent in the synthesis.
[0015] United States Patent Publication No. US 2003/0149264 describes chiral ionic liquids of the general formula: [A] n+ [Y] n− , whereby n=1 or 2 and the anion is an anion of an organic or inorganic proton acid and the cation is an optically active organic ammonium cation with up to 50 carbon atoms and at least one chiral centre and at least one functional group, whereby the functional group can produce a coordination by forming hydrogen bridges or providing free electron pairs and at least one chiral centre has a distance of up to 5 atomic bonds from the functional group. The ILs described herein may be used to separate racemates into individual enantiomers, as solvents for asymmetric inorganic and organic synthesis and also as solvents for asymmetric catalysis in organic and inorganic reactions. Typically the ILs find use as solvents for Diels-Alder reactions, benzoin reactions and asymmetric catalysis, in particular hydration and hydrovinylation.
[0016] More recently, tetra-n-hexyl-dimethylguanidinium (R)-mandelate, a chiral ionic liquid in which a mandelate anion is providing chirality, has been used as a solvent for asymmetric rhodium(II) carbenoid insertion by Alfonso.
[0000]
[0000] In this reaction an α-phosphono-α-diazoacetate was cyclized via a C—H insertion reaction in the presence of Rh 2 (OAc) 4 with a CIL solvent to give a γ-lactam in 72% yield, as a trans/cis mixture (67/33) and with 27% enantiomeric excess. However, undesirably, the IL may not be inert since the mandelate anion may potentially act as a nucleophile or base in many reactions.
[0017] Chiral ILs have also found use in the separation sciences. For example, United States Patent Publication No. US 2006/0025598 describes diionic liquid salts having a solid/liquid transition temperature of about 400° C. or less. The diionic liquid salt includes two monoionic groups separated by a bridging group and either two monoionic counter ions or at least one diionic counter ion. The diionic liquid salts may be immobilized as stationary phases for gas chromatography (GC). The IL stationary phases are said to be highly selective, stable and resistant to temperature degradation. In a preferred embodiment, the stationary phases are made from diionic species which are chiral and optically enhanced. In one embodiment the diion or the salt-forming species is chiral, with at least one stereogenic centre to provide racemic or optically enhanced mixtures.
[0018] U.S. patent application Ser. No. 11/177,093 describes optically enhanced chiral ionic liquids for gas chromatography and as a reaction solvent. Both optically enhanced chiral cationic and optically enhanced chiral anionic liquids are described. Optically enhanced chiral cations include (−)—N-benzyl-N-methylephedrinium NTf 2 , isoleucine-based ILs, menthol-substituted methyl imidazolium IL, (−)-cotinine OTf, 1-((R)-1,2-propanediol)-3-methylimidazolium chloride, and a (+)-chloromethyl methyl ether imidazolium IL salts, amongst others.
[0000]
Menthol Substituted IL 1-((R)-1,2-propanediol)-3-methylimidazolium chloride
[0019] Chinese Patent Application Publication No. 1 847 201 discloses chiral ionic liquids comprising an imidazole structure substituted with an amino containing group, and its preparation process and application in organic asymmetric catalytic Michael reactions, in which there is said to be excellent chiral catalytic performance. Examples of such compounds include:
[0000]
[0020] Matos et al recently described CILs based on menthol and borneol moieties linked to alkyl substituted imidazoles through ester functionalities. The introduction of the ester group is said to lead to improved properties such as polymer stabilization. The biodegradability of the compounds is not discussed nor is their success in the induction of chirality in non-chiral substrates.
[0000]
[0021] Recently, Luo et al published a review of functionalised chiral ionic liquids. This review gives an excellent overview of chiral ionic liquids role as organocatalysts or non-classical chiral ligands. Two examples of chiral pyridinium ionic liquids were included. Examples shown below:
[0000]
[0022] No biodegradation data or toxicity data has been reported, or indeed even discussed in this review. The environmental impact of the chiral ionic liquids as assessed by biodegradation and toxicity studies, has not been investigated by groups working in this area.
[0023] Many common ILs have been investigated as alternative solvents for catalytic hydrogenations. Of these studies, the greater part focus on common commercially available ILs of the form Rmim + (R: alkyl chain) X − . Palladium on Carbon is well known as a universal catalyst for olefin hydrogenation. However, its efficient catalytic activity may lead to poor selectivity.
[0024] Accordingly there is a need for additional ILs which combine desirable solvent properties such biodegradability and coordination ability in a solvent that can be tailored to the specific needs of reactions, for example, enhanced conversion and/or selectivity of product. Further examples of chiral ionic liquids are desirable, particularly those which have proven ability to act catalytically and/or induce chirality into the reaction manifold. Although some data clearly exist which indicate that chiral ionic liquids (CILs) have a degree of asymmetric catalytic ability, highly efficient CIL catalysts are limited in number. Thus the need for superior CILs which can optimize asymmetric induction, whilst minimizing any environmental impact is clearly desirable.
[0025] In summary, despite the “green” designation, many existing ILs have less than favourable biodegradation profiles and/or have associated toxicity to plant, animal and marine life. Therefore, more biodegradable and/or less toxic ILs are highly desired, particularly those which have the capability to provide a highly polar chiral solvent environment, with negligible vapour pressure and low flammability and that can be recycled after convenient separation of chemical reaction products for chemical reactions (especially those of industrial importance). The invention addresses these deficiencies to a useful degree.
SUMMARY OF THE INVENTION
[0026] According to a first aspect of the invention, there is provided a compound comprising an alkyl substituted imidazolium cationic core or an alkyl substituted pyridinium cationic core, having an alkyl ester side chain (-alkyl-C(O)O—) linked thereto and an associated counter anion,
[0027] characterized in that the —O— atom of the ester side chain links the side chain to an alpha, a beta or a gamma hydroxycarboxylic acid functionality via an alpha, a beta or a gamma hydroxy of the hydroxycarboxylic acid functionality, the hydroxycarboxylic acid functionality having at least one asymmetric carbon.
[0028] In a preferred embodiment, the compound of the invention comprises an alkyl substituted imidazolium cationic core.
[0029] It will be appreciated that an alkyl substituted imidazolium cationic core and an alkyl substituted pyridinium cationic core comprises at least one N atom in the cyclic core. It will be further apprecitated that the core may comprises at least one —N═ atom in the cyclic core.
[0030] Accordingly, in a preferred embodiment, there is provided a compound comprising an alkyl substituted imidazolium cationic core or an alkyl substituted pyridinium cationic core, having an associated counter anion,
[0031] characterized in that an —N═ atom of the alkyl substituted imidazolium cationic core or an —N═ atom of the alkyl substituted pyridinium cationic core is substituted with an alpha, a beta or a gamma hydroxy group of an alpha, a beta or a gamma hydroxycarboxylic acid functionality and the hydroxycarboxylic acid functionality has at least one asymmetric carbon.
[0032] In other words, the unsubstituted —N— atom of the 1-substituted imidazole or the pyridine directly replaces the alpha, beta, or gamma-hydroxyl of alpha, beta or gamma hydroxy of the acid functionality to give an imidazolium-substituted or the pyridinium-substituted carboxylic acid functionality that has at least one asymmetric carbon.
[0033] The skilled person will appreciate that the —N═ atom of the cationic core (imidazolium or pyridinium) is substituted for the alpha, beta or gamma —OH group of the alpha, a beta or a gamma hydroxycarboxylic acid functionality. In other words, the —N═ atom replaces the —OH group of the alpha, a beta or a gamma hydroxycarboxylic acid functionality.
[0034] In a preferred embodiment, the —N═ atom is of an alkyl substituted imidazolium cationic core.
[0035] In a preferred embodiment, the alkyl substituted imidazolium cationic core or the alkyl substituted pyridinium cationic core is substituted with an alkyl group of the general formula C n H 2n+1 derived from aliphatic hydrocarbons. Alkyl chains can be straight or branched. Particuarly preferred are C 1 -C 4 alkyl groups.
[0036] The compounds of the invention may be utilised as ionic liquid solvents, particularly chiral ionic liquid solvents (CILs). Advantageously, incorporating the hydroxylcarboxylic acid moiety into the cationic part of the chiral ionic liquid (CIL) molecule, blocks both the normally nucleophilic acid and hydroxyl groups as esters and so (provided there are no strong nucleophiles present, or strong hydrolytic acid or base), the CIL should not interfere with a reaction process and will remain relatively inert. Furthermore, the chirality of the molecule advantageously may assist in inducing sterochemistry into the reaction products and/or enhancing the selectivity and/or reaction conversion rates.
[0037] The compounds of the invention are desirable, since they form part of an expandable designer library of ionic liquid solvents that possess tuneable characteristics and yet are economically viable, robust and ideally suited to the preparation of drugs. The ionic liquids of the invention yield an excellent commercial source for tuneable chiral coordinating, biodegradable and non-toxic solvents.
[0038] In a preferred embodiment, a compound of the invention may have general formula (I)
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl or C 1 -C 4 alkoxy;
[0039] R 2 is a —H or C 1 -C 4 alkyl; and
[0040] Y is:
[0000]
[0041] R′, R″, X′, X″, Z′ and Z″ are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0042] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carbonate; carbamate; or wherein two adjacent substitutions together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprises at least one heteroatom N, O or S,
[0043] with the provision that R′ and R″ are not simultaneously identical groups; and
[0044] wherein Y is linked to the ester group oxygen of general formula I at the alpha, beta or gamma asymmetric carbon (*) of the group Y.
[0045] It will be appreciated that A − is a counter anion. In a preferred embodiment, a compound of the invention may have general formula (II)
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl or C 1 -C 4 alkoxy;
[0046] R 2 is a —H or C 1 -C 4 alkyl; and
[0047] Y is:
[0000]
[0048] R′ and R″ and X are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0049] R′″ is —H, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, a C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0050] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carbonate; carbamate; or wherein two adjacent substitutions together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprises at least one heteroatom N, O or S,
[0051] with the provision that R′ and R″ are not simultaneously identical groups; and
[0052] wherein Y is linked to the ester group oxygen of general formula II at the alpha, beta or gamma asymmetric carbon (*) of the group Y.
[0053] It will be appreciated that A − is a counter anion.
[0054] Compounds of this aspect of the invention include those based on the following structures:
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl or C 1 -C 4 alkoxy;
[0055] R 2 is a —H or C 1 -C 4 alkyl; and
[0056] R′, R″, X″, X′, Y′ and Y″ are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0057] R′″ is —H; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0058] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carbonate; carbamate; or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S,
[0059] with the provision that R′ and R″ are not simultaneously identical groups.
[0060] It will be appreciated that A − is a counter anion.
[0061] In a particularly preferred embodiment, a compound of the invention may have general formula (III)
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl or C 1 -C 4 alkoxy;
[0062] R 2 is a —H or C 1 -C 4 alkyl; and
[0063] Y is:
[0000]
[0064] R′″ is —H, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, a C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0065] R 3 , R 4 , R 5 , R 6 and R 7 are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate; or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and
[0066] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carbonate; carbamate; or wherein two adjacent substitutions together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprises at least one heteroatom N, O or S; and
[0067] wherein Y is linked to the ester group oxygen of general formula II at the alpha, beta or gamma asymmetric carbon (*) of the group Y.
[0068] In another preferred embodiment, a compound of the invention may have general formula (III)
[0000]
[0069] wherein R 1 , R 2 , R 3 , R 4 , R 5 are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate; or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and
[0000] wherein the cyclohexyl; aryl; heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprises at least one heteroatom N, O or S;
[0070] Y is:
[0000]
[0071] R′, R″, X′, X″, Z′ and Z″ are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; a heteroaryl group; a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0072] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprises at least one heteroatom N, O or S,
[0073] with the provision that R′ and R″ are not simultaneously identical groups; and
[0074] wherein Y is linked to the ester group oxygen of general formula III at the alpha, beta or gamma asymmetric carbon (*) of the group Y.
[0075] It will be appreciated that A − is a counter anion.
[0076] In a preferred embodiment, a compound of the invention may have general formula (IV)
[0000]
[0077] wherein R 1 , R 2 , R 3 , R 4 , R 5 are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and
[0078] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring; and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S; and
[0079] Y is:
[0000]
[0000] and
[0080] R′ and R″ and X are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0081] R′″ is —H; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0082] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S,
[0083] with the provision that R′ and R″ are not simultaneously identical groups; and wherein Y of general formula (IV) is linked to the alpha, beta or gamma asymmetric carbon (1 of the group Y.
[0084] It will be appreciated that A − is a counter anion.
[0085] Compounds of this aspect of the invention include those based on the following structures:
[0000]
[0086] wherein R 1 , R 2 , R 3 , R 4 , R 5 are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring; and
[0087] wherein the cyclohexyl; aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S; and
[0088] R′, R″, X″, X′, Y′ and Y″ are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0089] R′″ is —H, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, a C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0090] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S,
[0000] with the provision that R′ and R″ are not simultaneously identical groups.
[0091] It will be appreciated that A − is a counter anion.
[0092] In a preferred embodiment, a compound of the invention may have general formula (V)
[0000]
[0093] wherein R 1 , R 2 , R 3 , R 4 , R 5 are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and
[0094] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring; and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S; and
[0095] Y is:
[0000]
[0096] R′″ is —H, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, a C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0097] R 6 , R 7 , R 8 , R 9 and R 10 are independently —H; —OH; —CF 3 ; a cyclohexyl; an aryl; a heterocyclic; heteroaryl group; a nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and
[0098] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carboxylic amide; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S,
[0099] with the provision that R′ and R″ are not simultaneously identical groups; and wherein Y of general formula (V) is linked to the alpha, beta or gamma asymmetric carbon (*) of the group Y.
[0100] It will be appreciated that A − is a counter anion. Used herein, an alkyl group is any of a series of univalent groups of the general formula C n H 2n+1 derived from aliphatic hydrocarbons. Alkyl chains can be straight or branched. The skilled person will appreciate that straight means linear and unbranched. The methyl group (—CH 3 ) represents a C 1 alkyl group, ethyl (—C 2 H 5 ) represents a C 2 alkyl group, nonyl group represents a C 9 alkyl group, dodecyl group represents a C 12 group, etc.
[0101] An ether group has an oxygen atom connected to two alkyl groups, which may be further derivatized (general formula R—O—R′). A typical example is ethoxyethane (CH 3 —CH 2 —O—CH 2 —CH 3 ).
[0102] An ester group may be represented by RC(O)—OR and comprises an acid hydroxy group adjacent to a carbonyl group, wherein the acid hydroxy group is esterified. An alkyl ester group may be represented by -alkyl-C(O)—O—R, wherein the alkyl group is as defined above.
[0103] An acid amide may be represented by RC(O)NHR, in the case of a primary amide. A secondary amide group may be represented by RC(O)NR′R″, wherein the R′ and R″ may be the same or different.
[0104] A thioester may be represented by the group RC═S—OR.
[0105] As described herein, when an alkyl group is said to comprises at least one ether linkage, this is intended to mean that at least one carbon (—HCH—) in the alkyl chain is substituted by an oxygen (—O—) atom, to give an alkyl chain containing at least one ether linkage. The number of carbon atoms substituted by oxygen depends on the number of ether linkages provided in the chain.
[0106] A chiral or stereogenic carbon is a carbon atom which is asymmetric. A chiral or asymmetric carbon to be chiral, it follows that the carbon atom is sp 3 -hybridized and there are four different groups attached to the carbon atom or stereogenic centre.
[0107] In a preferred embodiment, the compounds of the invention have an alkyl ester side chain in which the alkyl terminus is directly attached to the imidazole ring at the 3-position or pyridine ring at the 1 position. This means that the -alkyl-C(O)OR side chain is directly attached to a nitrogen of the imidazolium ring or nitrogen of the pyrdinium ring through the -alkyl-group end of the side chain. For example, if the -alkyl-C(O)OR side chain is a methyl ester side chain, then the ester functionality is one carbon away from the nitrogen hetrocycle core. If the -alkyl-C(O)OR side chain is an ethyl ester side chain, then the ester functionality is two carbon atoms away from the core, and so on. It is preferred that the alkyl ester side chain comprises a methyl, ethyl or propyl alkyl group, the alkyl terminus of which is preferably directly linked to the nitrogen atom of the imidazolium ring or nitrogen of the pyridinium ring. Most preferred of all, are compounds which comprise methyl ester side chains (—CH 2 C(O)OR) wherein the methyl groups links the ester functionality to the nitrogen of the imidazolium ring. These structures are favoured because a good balance between easy of synthesis, stability, low antimicrobial toxicity and high biodegradability is achieved.
[0108] In one embodiment, the compounds of the invention comprise an alpha or a beta or a gamma hydroxycarboxylic acid functionality, wherein the acid functionality may be a carboxylic acid group (—COOH), a C 1 -C 6 acid ester group (—COOR), a C 1 -C 6 acid amide group (—CONHR or —CONRR) or a C 1 -C 6 acid thioester group (—CSOR), wherein R independently represents a C 1 -C 6 alkyl group or a C 1 -C 6 alkyl ether group, both of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain. In particularly preferred compounds, R is a C 1 -C 6 alkyl ether group having one ether oxygen substituted into the alkyl chain to replace one carbon atom therein.
[0109] Thus, the compounds of the invention may be derived from any of the chiral alpha, beta or gamma hydroxy carboxylic acid building blocks shown below or derivates of same, wherein the molecules may be derivatized by further substitution with groups R, —OH, X or Y, as described later herein.
[0110] The CIL compounds of the invention comprise an alkyl ether side chain linked to the IL core, wherein the —O— atom of the alkyl ester bond is derived from the alpha hydroxyl group of a chiral alpha hydroxycarboxylic acid functionality or comprise a chiral beta hydroxy group of a beta hydroxycarboxylic acid functionality or a chiral gamma hydroxy group of a gamma hydroxycarboxylic acid functionality (—O— atom of the alkyl ester bond is highlighted in bold as the oxygen of the hydroxy group in the moieties below). The hydroxy group from which the alkyl ester bond is derived is indicated in bold in the representative structure below.
[0000]
[0111] Preferably, the compounds of the invention comprise at least one chiral (asymmetric) centre. at The least one chiral centre is preferably located at the asymmetric (stereogenic) carbon which is substituted with the alkyl ester group which links the chiral moiety to the IL core (corresponds to the carbon substituted with the hydroxy of the carboxylic acid moiety, the hydroxy is indicated in bold above). Other possible asymmetric carbon sites are shown in the representative molecules above, to which the groups X may be directly attached. The chiral centre(s) have four different groups attached thereto. Suitably, R and X may be different and may be independently selected from the group consisting of —H, —OH, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched and the alkyl ether group comprises at least one ether linkage in the alkyl chain; wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di- or tri-substituted with substituents independently selected from hydrogen, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate, carbamate or two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heteroaryl group comprising at least one heteroatom N, O or S; with the provision that R and X are not both simultaneously identical groups. In other words, substituents R and X cannot be identical, since if this is the case, the carbon to which the groups are attached is not asymmetric (the molecule may still be chiral if an axis of chirality is present even without stereocentres). Accordingly, the compounds of the invention comprise compounds in racemic mixtures where the enantiomers are present in equal amounts or in enantiomeric mixtures wherein one enantiomer is present in excess of another or indeed enantiomerically pure where the compound of the invention is available as 100% enantiomer.
[0112] In one preferred embodiment, the compounds of the invention comprise a chiral alpha, a chiral beta or a chiral gamma hydroxycarboxylic acid functionality, wherein the acid functionality is a C 1 -C 6 acid ester group —COOR, wherein R is a C 1 -C 6 alkyl group or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain. The compounds are advantageous since they may easily be further derivatized at any of the reactive groups present. Furthermore, the compounds containing coordinating carbonyl and ester oxygen sites which may advantageously interact with reactants in a positive manner with regard to promoting or enhancing stereoinduction, product selectivity and conversion in a chemical reaction in which the CIL is employed as solvent or co-solvent etc.
[0113] In another embodiment, the compounds of the invention comprise a chiral alpha, a chiral beta or a chiral gamma hydroxycarboxylic acid functionality, wherein the acid functionality is a C 1 -C 6 acid amide group —CONHR or —CONRR, wherein R is independently a C 1 -C 6 alkyl group or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain, or R and R together may form a heterocyclic ring having 5 to 7 atoms, wherein the ring may comprise at least one other heteroatom in addition to the amide nitrogen. Preferably the heterocyclic ring comprises 6 atoms in the ring. Particularly preferred compounds comprise a heteroatom ring, which comprises at least one oxygen atom, such as cyclic ethers. Such compounds would be desirable, since they may have improved stability over the ester analogous compounds. In addition, the amides may have superior co-coordinating properties than the ester versions. Primary and secondary amide CILs may advantageously have additional desirable hydrogen bonding properties.
[0114] In a different embodiment, the compounds of the invention comprise an alpha, a beta or a gamma hydroxycarboxylic acid functionality, wherein the acid functionality is a C 1 -C 6 thioester group —CSOR, wherein R a C 1 -C 6 alkyl group or a C 1 -C 6 alkyl ether group both of which may be branched or unbranched and the alkyl ether group comprises at least one ether linkage in the alkyl chain. These ILs may be advantageous in reactions involving enzymes. They may be desirable in reactions that involve heavy metals.
[0115] In a preferred embodiment, the compounds of the invention comprise a chiral alpha hydroxycarboxylic acid functionality, which may be a malic acid functionality, a lactic acid functionality or mandelic acid functionality. However, the malic acid functionality, a lactic acid functionality or mandelic acid functionality are particularly preferred in the CIL compound of the present invention.
[0116] In another preferred embodiment, the compounds of the invention comprise a chiral beta hydroxycarboxylic acid functionality which may be a 3-hydroxybutyric acid functionality, a 3-hydroxyvaleric acid functionality, a 3-hydroxyhexanoic acid functionality or a 3-hydroxy-3-phenyl propanoic acid functionality. Particularly preferred are 3-hydroxy acid functionalities of bacterial origin that will advantageously have high biodegradability and/or biorenewability. Advantageously, β-hydroxy acids readily link into biochemical pathways because of β-oxidation in fatty acid chains. Notably β-hydroxy carbonyls are aldols and the side-chain can readily cleave by elimination, which favours CIL degradation.
[0117] The compounds of the invention have imidazolium or pyridinium cores which may be substituted around the imidazolium or pyridinium ring by at least one C 1 -C 5 alkyl substituent, C 1 -C 5 alkoxy substituent or by at least one halogenated alkyl substituents. Suitably, the alkyl substituted imidazolium core may possess a C 1 -C 4 alkyl substituent at the 1-position of the imidazolium core. However, C 1 -C 2 alkyl substituents at the 1-position are the preferred substituents. The most favoured substituents are methyl substituents at the 1-position.
[0118] It is also possible to have further substituents on the imidazolium or pyrimidium ring, such further substituent may be at least one C 1 -C 5 alkyl substituent or at least one halogenated alkyl substituent, such as trifluoromethyl.
[0119] Thus, the compounds of the invention comprise IL compounds having an alkyl substituted imidazole ring which may be substituted in at least one position with an alkyl group selected from the group consisting of 1-methyl, 2-methyl, 4-methyl, 5-methyl, 1-ethyl, 2-ethyl, 4-ethyl, 5-ethyl, 1-propyl, 2-propyl, 4-propyl, 5-propyl or a 4-trifluoromethyl group, which may be suitably branched or unbranched. The most preferred compounds of the invention comprise a 1-methyl or 1 ethyl substituent on the imidazolium core. However, the most preferred alkyl substituent is a 1-methyl substituent on the 1 position of the imidazolium ring.
[0120] Suitably, the negatively charged counter anion (A) may be selected from the group consisting of: Cl, Br, I, PF 6 , BF 4 , OctOSO 3 , CH 3 OSO 3 , SO 4 , NTf 2 or N(CN) 2 , tosylate, hydroxylate, camphorsulfonate, mandelate, lactate, tartrate, quinate, carboxylate derivatives of aminoacids, hydrogen sulfate, methyl sulfate, ethyl sulfate, butyl sulfate, hexyl sulfate, heptadecafluorooctanesulfonate, 2-(2-methoxyethoxy)-ethylsulfate, methanesulfonate, trifluoromethanesulfonate, nonafluorobutanesulfonate, p-toluenesulfonate, phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dihexyl phosphate, dioctyl phosphate, bis(pentafluoroethyl)phosphinate, bis(2,4,4-trimethylpentyl)-phosphinate, tris(pentafluoroethyl)trifluorophosphate, tris(heptafluoropropyl)trifluorophosphate, tris(nonafluorobutyl)trifluorophosphate, diethylphosphate, nitrate, thiocyanate, tricyanomethanide, bis(pentafluoroethylsulfonyl)imide, bis(trifluoromethyl)imide, tris(trifluoromethylsulfonyl)methide, bis(methanesulfonyl)amide, 2,2,2-trifluoro-N-(trifluoromethylsulfonyl)acetamide, tetracyanoborate, bis[oxalato]borate, bis-[1,2-benzenediolato(2-) ]borate, bis-[salicylato(2-)]borate, bis-[malonato(2-)]-borate, bis-[2,2′biphenyl-diolato-(2-)-O,O′]-borate, acetate, trifluoroacetate, decanoate, hexafluoroantimonate, tetrachloroaluminate and cobalttetracarbonyl.
[0121] Particularly preferred anions are Cl, Br, I, PF 6 , BF 4 , OctOSO 3 , CH 3 OSO 3 , SO 4 , NTf 2 or N(CN) 2 .
[0122] Suitably, the negatively charged counter anion may be Br, PF 6 , BF 4 , OctOSO 3 , CH 3 OSO 3 , SO 4 , NTf 2 or N(CN) 2 . Desirably, anions may be OctOSO 3 , NTf 2 or N(CN) 2 .
[0123] The most preferred anion is OctOSO 3 . The person skilled in the art will appreciate that many other counteranions may be suitably used, with low toxicity examples such as OctOSO 3 , CH 3 OSO 3 , HSO 4 , and SO 4 being especially preferred.
[0124] In a particularly preferred embodiment, the compounds of the invention have general formula V or VI
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl or C 1 -C 4 alkoxy;
[0125] R 2 is a —H or C 1 -C 4 alkyl;
[0126] R′ is —H, —OH, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, a C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0127] R″ is a —H, —OH, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain
[0128] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate, carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S,
[0129] with the provision that R′ and R″ are not simultaneously identical groups;
[0130] R 3 is a C 1 -C 6 alkyl, or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0131] A − is Br, PF 6 , BF 4 , OctOSO 3 , NTf 2 or N(CN) 2 .
[0132] Suitably, the C 1 -C 6 alkyl ether group may include groups such as —CH 2 CH 2 OCH 3 , —CH— 2 CH 2 OCH 2 CH 3 , —CH 2 CH 2 OCH 2 CH 2 CH 2 CH 3 or —CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 3 . Branched analogues also fall within the scope of the invention.
[0133] Suitable aryl groups include phenyl, suitable heterocyclic rings include pyrrolidine and heteroaryl rings comprise pyridine or pyrrole etc.
[0134] In a particularly preferred embodiment, the compounds of the invention have general formula V or VI
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl;
[0135] R 2 is a —H or a C 1 -C 4 alkyl;
[0136] R′ is —H, —OH, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0137] R″ is a —H, —OH, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain,
[0138] with the provision that R′ and R″ are not simultaneously identical groups;
[0139] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri or tetra-substituted with substituents independently selected from —H; hydroxy; C 1 -C 6 alkyl; C 1 -C 6 alkoxy; nitro; halo; acyl; phosphine (PR 2 ); diarylphosphine (PAr 2 ); phosphate; phosphite; sulfate; sulfite; phosphonamide; phosphinamide; sulfonamide; sulfonimide; sulfinamide; sulfinimide; carboxylic ester; carbonate; carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprises at least one heteroatom N, O or S; and
[0140] R 3 is a C 1 -C 6 alkyl, or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0141] A is OctOSO 3 or NTf 2 .
[0142] In a particularly preferred embodiment, R″ is —CH 3 .
[0143] Suitably, the C 1 -C 6 alkyl ether group may be —CH 2 CH 2 OCH 3 , —CH 2 CH 2 OCH 2 CH 3 , —CH— 2 CH 2 OCH 2 CH 2 CH 2 CH 3 or —CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 3 . Branched alkyl ester analogues also fall within the scope of the invention.
[0144] Suitably, the preferred compounds of the invention have a chiral alpha hydroxycarboxylic acid functionality which comprises a lactic acid functionality or a mandelic acid functionality. Particularly preferred compounds are those comprising the mandelate functionality having an aryl group substituent on the asymmetric carbon to which the chiral alpha hydroxy group (esterified in the CIL molecule) is attached, since these examples are expected to exhibit superior potential substrate interaction sites. In one embodiment, the compounds comprise a chiral beta hydroxycarboxylic acid functionality, which may be a chiral beta-hydroxybutyric acid functionality or a chiral 3-hydroxy-3-phenyl propanoic acid functionality. Suitably, the cyclohexyl, aryl, heterocyclic or heteroaryl groups of the mandelic acid functionality or the 3-hydroxy-3-phenyl propanoic acid functionality may be mono-, di-, tri- or tetra-substituted with substituents independently selected from the group consisting of: —H, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate and carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprises at least one heteroatom N, O or S. Preferred compounds are those having a chiral esterified hydroxy carboxylic acid functionality with a di-substituted cyclohexyl, aryl, heterocyclic or heteroaryl ring. Preferred ring di-substitutions include adjacent hydroxy, C 1 -C 6 alkoxy substitutions or examples where the di substitions form a 3,4 methylenedioxy ring structure
[0145] The remaining position on the chiral alpha asymmetric carbon may be substituted with —OH, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain; wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from the group consisting of: —H, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate and carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprises at least one heteroatom N, O or S.
[0146] In a preferred embodiment, the compounds of the invention have general formula VI or VII
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl or C 1 -C 4 alkoxy;
[0147] R 2 is —H or a C 1 -C 4 alkyl;
[0148] R′ is —H, —OH, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, a heteroaryl group, a C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain,
[0149] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate, carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S,
[0150] with the provision that R′ is not simultaneously identical with the R 4 , R 5 disubstituted aryl group;
[0151] R 3 is a C 1 -C 6 alkyl, or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0152] R 4 R 5 R 6 R 7 and R 8 are independently from —H, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate, carbamate or two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring,
[0153] A is OctOSO 3 NTf 2 or N(CN) 2 .
[0154] Suitably, the C 1 -C 6 alkyl ether group may be —CH 2 CH 2 OCH 3 , —CH 2 CH 2 OCH 2 CH 3 , —CH— 2 CH 2 OCH 2 CH 2 CH 2 CH 3 or —CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 3 . Branched alkyl ester analogues also fall within the scope of the invention.
[0155] In a particularly preferred embodiment, R′ is —H.
[0156] In a preferred embodiment, the compounds of the invention have general formula IX or X
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl or C 1 -C 4 alkoxy;
[0157] R 2 is —H or a C 1 -C 4 alkyl;
[0158] R′ is —H, —OH, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, a heteroaryl group, a C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain,
[0159] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri- or tetra-substituted with substituents independently selected from —H, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate, carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S,
[0160] with the provision that R′ is not simultaneously identical with the R 4 , R 5 disubstituted aryl group;
[0161] R 3 is a C 1 -C 6 alkyl, or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0162] R 4 and R 5 are independently from —H, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate, carbamate or two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring,
[0163] A is OctOSO 3 NTf 2 or N(CN) 2 .
[0164] Suitably, the C 1 -C 6 alkyl ether group may be —CH 2 CH 2 OCH 3 , —CH 2 CH 2 OCH 2 CH 3 , —CH— 2 CH 2 OCH 2 CH 2 CH 2 CH 3 or —CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 3 . Branched alkyl ester analogues also fall within the scope of the invention.
[0165] In a particularly preferred embodiment, R′ is —H.
[0166] In a preferred embodiment, the compounds of the invention have general formula IX or X
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl;
[0167] R 3 is a C 1 -C 6 alkyl or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0168] R 4 and R 5 are independently from hydrogen, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate, carbamate or two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring; and
[0169] A is OctOSO 3 , NTf 2 or N(CN) 2 .
[0170] Suitably, the C 1 -C 6 alkyl ether group may be —CH 2 CH 2 OCH 3 , —CH 2 CH 2 OCH 2 CH 3 , —CH— 2 CH 2 OCH 2 CH 2 CH 2 CH 3 or —CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 3 . Branched alkyl ester analogues also fall within the scope of the invention.
[0171] In a preferred embodiment, the compounds of the invention have general formula IX or X
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl;
[0172] R 4 and R 5 are independently —H, a C 1 -C 6 alkyl, a C 1 -C 6 alkoxy or together form a methylenedioxy ring;
[0173] R 3 is a C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0174] A is OctOSO 3 or NTf 2
[0175] Suitably, the C 1 -C 6 alkyl ether group may be —CH 2 CH 2 OCH 3 , —CH 2 CH 2 OCH 2 CH 3 , —CH— 2 CH 2 OCH 2 CH 2 CH 2 CH 3 or —CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 3 . Branched alkyl ester analogues also fall within the scope of the invention.
[0176] In a preferred embodiment, the compounds of the invention have general formula IX or X
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl;
[0177] R 4 and R 5 are independently —H, a C 1 -C 6 alkyl, a C 1 -C 6 alkoxy or together form a methylenedioxy ring;
[0178] R 3 is a C 1 -C 6 alkyl; and
[0179] A is OctOSO 3 or NTf 2 .
[0180] In one embodiment, the compounds of the invention comprising a chiral hydroxy carboxylic acid functionality having an aryl substituent on the asymmetric carbon (such as the mandelate based system), is considerably more versatile because the aromatic ring can be readily functionalised. Thus, the ionic liquids in the present invention allow convenient solvent tailoring.
[0181] These functionalised aromatic rings have a great deal of potential, either for hydrogen bonding (to catalyse reactions (e.g. Diels-Alder or aid chromatography), to bind metals (e.g. iron) or attach groups such as phosphoryl (with organocatalytic possibilities) and sulfonyl or to activate the aromatic ring to scavenge electrophiles, especially cations (e.g. in peptide deprotection from a solid support) or act as an anti-oxidant as a biodegradable alternative to Song's and Wang's electrophile-scavenging ILs. The possibility of forming separate phases, especially triphasic systems means that the CILs in the present invention present an alternative to expensive fluorous scavengers (Basle). Furthermore, the presence of electron-donating groups on the aromatic will make it easier to further functionalise the ring by electrophilic aromatic substitution, e.g. with nitro or halogens. Suitable substitutions have already been discussed earlier.
[0182] In a different preferred embodiment, the compounds of the invention comprise general formula XI, XII or XIII
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl;
[0183] R 2 is a —H or a C 1 -C 4 alkyl;
[0184] R′ is —H, —OH, —CF 3 , a cyclohexyl, an aryl, a heterocyclic, heteroaryl group, C 1 -C 6 alkyl, a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain;
[0185] wherein the cyclohexyl, aryl, heterocyclic or heteroaryl groups may be mono-, di-, tri or tetra-substituted with substituents independently selected from —H, hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, nitro, halo, acyl, phosphine (PR 2 ), diarylphosphine (PAr 2 ), phosphate, phosphite, sulfate, sulfite, phosphonamide, phosphinamide, sulfonamide, sulfonimide, sulfinamide, sulfinimide, carboxylic ester, carbonate, carbamate or wherein two adjacent substitutions which together form a C 1 -C 4 alkylenedioxy ring, and wherein the heterocyclic or heteroaryl group comprising at least one heteroatom N, O or S;
[0186] R 4 and R 5 are independently —H, a C 1 -C 6 alkyl, a C 1 -C 6 alkoxy or together form a methylenedioxy ring;
[0187] R 3 is a C 1 -C 6 alkyl, or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain,
[0188] with the provision that R′ is not simultaneously identical to a group attached to the asymmetric centre marked *; and
[0189] A is OctOSO 3 , NTf 2 or N(CN) 2 .
[0190] Suitably, the C 1 -C 6 alkyl ether group may be —CH 2 CH 2 OCH 3 , —CH 2 CH 2 OCH 2 CH 3 , —CH— 2 CH 2 OCH 2 CH 2 CH 2 CH 3 or —CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 3 . Branched alkyl ester analogues also fall within the scope of the invention.
[0191] In a different preferred embodiment, the compounds of the invention comprise general formula XIV, XV or XVI
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl;
[0192] R 2 is a —H or a C 1 -C 4 alkyl;
[0193] R 3 is a C 1 -C 6 alkyl, or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0194] A is OctOSO 3 or NTf 2 .
[0195] In a different preferred embodiment, the compounds of the invention comprise general formula XVII, XVIII or XIX
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl;
[0196] R 3 is a C 1 -C 6 alkyl, or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched and the alkyl ether group comprises at least one ether linkage in the alkyl chain; and
[0197] A is OctOSO 3 or NTf 2 .
[0198] Suitably, the C 1 -C 6 alkyl ether group may be —CH 2 CH 2 OCH 3 , —CH 2 CH 2 OCH 2 CH 3 , —CH— 2 CH 2 OCH 2 CH 2 CH 2 CH 3 or —CH 2 CH 2 OCH 2 CH 2 OCH 2 CH 3 . Branched alkyl ester analogues also fall within the scope of the invention.
[0199] In a different preferred embodiment, the compounds of the invention comprise general formula XVII, XVIII or XIX
[0000]
[0000] wherein R 1 is a C 1 -C 4 alkyl;
[0200] R 3 is a C 1 -C 6 alkyl; and
[0201] A is OctOSO 3 or NTf 2 .
[0202] In the various embodiments of the invention described thus far, it is preferred that the chiral carboxylic acid functionality comprises an acid ester group which may be represented by —COOR 3 , wherein R 3 is preferably a C 1 -C 6 alkyl group or a C 1 -C 6 alkyl ether group, either of which may be branched or unbranched, and the alkyl ether group comprises at least one ether linkage in the alkyl chain. Most preferred compounds of the invention comprise C 1 -C 6 alkyl groups in R 3 position.
[0203] In the various embodiments described thus far, it is preferred that the alkyl substituent on the 1 position of the imidazolium ring is a methyl substituent or an ethyl substituent (R 1 is methyl or ethyl).
[0204] In the various embodiments described thus far, it is preferred that the alkyl substituent on the 2 position of the imidazolium ring is —H or a methyl substituent (R 1 is methyl).
[0205] In any of the embodiments described herein, the preferred compounds of the invention are those having a counter anion (A − ) is OctOSO 3 or NTf 2 . Particularly preferred compounds are those having anion A − is OctOSO 3 , since these compounds are all readily biodegradable, producing a score of at least 60% degradation over 28 days in the CO 2 Headspace Test. Compounds comprising NTf 2 are preferred, where CILs of lower viscosity are required.
[0206] Preferred CILs are from the following list:
[0000]
KG No.
Name
KG 86
RS-3-methyl-1-[1-(methoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 87
R-3-methyl-1-[1-(methoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 88
S-3-methyl-1-[1-(methoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 89
RS-3-methyl-1-[1-(methoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 90
R-3-methyl-1-[1-(methoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 91
S-3-methyl-1-[1-(methoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 92
RS-3-methyl-1-[1-(methoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 93
R-3-methyl-1-[1-(methoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 94
S-3-methyl-1-[1-(methoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 150
RS-3-methyl-1-[1-(methoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 151
R-3-methyl-1-[1-(methoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 152
RS-3-methyl-1-[1-(ethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 153
R-3-methyl-1-[1-(ethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 154
RS-3-methyl-1-[1-(propoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 155
R-3-methyl-1-[1-(propoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 156
RS-3-methyl-1-[1-(butoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 157
R-3-methyl-1-[1-(butoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 158
RS-3-methyl-1-[1-(pentoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 159
R-3-methyl-1-[1-(pentoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 160
RS-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 161
R-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 162
RS-3-methyl-1-[1-(methoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 163
R-3-methyl-1-[1-(methoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 164
RS-3-methyl-1-[1-(ethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 165
R-3-methyl-1-[1-(ethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 166
RS-3-methyl-1-[1-(propoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 167
R-3-methyl-1-[1-(propoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 168
RS-3-methyl-1-[1-(butoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 169
R-3-methyl-1-[1-(butoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 170
RS-3-methyl-1-[1-(pentoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 171
R-3-methyl-1-[1-(pentoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 172
RS-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 173
R-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 300
S-3-methyl-1-[1-(ethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 301
R-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 302
S-3-methyl-1-[1-(pentoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 303
R-3-methyl-1-[1-(pentoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 304
RS-3-methyl-1-[1-(pentoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 305
S-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 306
S-3-methyl-1-[1-(butoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 307
RS-3-methyl-1-[1-(ethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 308
RS-3-methy1-1-[1-(butoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 400
RS-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 401
R-3-methyl-1-[1-(ethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 800
RS-3-methyl-1-[1-(methoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 801
RS-3-methyl-1-[1-(ethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 802
RS-3-methyl-1-[1-(propoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 803
RS-3-methyl-1-[1-(butoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 804
RS-3-methyl-1-[1-(pentoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 805
RS-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 806
R-3-methyl-1-[1-(methoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 807
R-3-methyl-1-[1-(ethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 808
R-3-methyl-1-[1-(propoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 809
R-3-methyl-1-[1-(butoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 810
R-3-methyl-1-[1-(pentoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 811
R-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 812
RS-3-methyl-1-[1-(ethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 813
RS-3-methyl-1-[1-(ethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 814
RS-3-methyl-1-[1-(butoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 815
RS-3-methyl-1-[1-(butoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 816
RS-3-methyl-1-[1-(pentoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 817
RS-3-methyl-1-[1-(pentoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 818
RS-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 819
RS-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 820
S-3-methyl-1-[1-(ethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 821
S-3-methyl-1-[1-(ethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 822
S-3-methyl-1-[1-(butoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 823
S-3-methyl-1-[1-(butoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 824
S-3-methyl-1-[1-(pentoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 825
S-3-methyl-1-[1-(pentoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 826
S-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 827
S-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 828
R-3-methyl-1-[1-(ethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 829
R-3-methyl-1-[1-(ethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 830
R-3-methyl-1-[1-(butoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 831
R-3-methyl-1-[1-(butoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 832
R-3-methyl-1-[1-(butoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium octyl sulphate
KG 833
R-3-methyl-1-[1-(pentoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 834
R-3-methyl-1-[1-(pentoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 835
R-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium bromide
KG 836
R-3-methyl-1-[1-(ethoxyethoxycarbonyl)-1-phenylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 1020
RS-2-(3,4-methylendioxyphenyl)-2-(3-methylimidazolium) butyl acetate bromide salt
KG 1022
RS-3-methyl-1-[1-(butoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]imidazolium
bromide
KG 1025
RS-2-(3,4-dihydroxyphenyl)-2-(3-methylimidazolium) methyl acetate chloride salt
KG 1026
RS-3-methyl-1-[1-(butoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]imidazolium
octyl sulphate
KG 1027
RS-3-butyl-1-[1-(butoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]imidazolium
bromide
KG 1029
RS-3-methyl-1-[1-(butoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 1034
RS-3-methyl-1-[1-(methoxycarbonyl)-1-(4-bromophenyl)methoxycarbonylmethyl]imidazolium bromide
KG 1035
RS-3-methyl-1-[1-(methoxycarbonyl)-1-(4-trifluoromethylphenyl)methoxycarbonylmethyl]imidazolium
bromide
KG 1036
RS-3-methyl-1-[1-(methoxycarbonyl)-1-(4-methoxyphenyl)methoxycarbonylmethyl]imidazolium
bromide
KG 1037
RS-3-butyl-1-[1-(butoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 1038
RS-3-butyl-1-[1-(butoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]imidazolium
octyl sulphate
KG 1039
RS-3-methyl-1-[1-(methoxycarbonyl)-1-(4-methoxyphenyl)methoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 1040
RS-3-methyl-1-[1-(methoxycarbonyl)-1-(4-trifluoromethylphenyl)methoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
KG 1041
RS-2-(3,4-dihydroxyphenyl)-2-(3-methylimidazolium) methyl acetate bromide salt
KG 1042
RS-2-(3,4-dihydroxyphenyl)-2-(3-methylimidazolium) methyl acetate octyl sulphate salt
KG 1043
RS-[1-(butoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]pyridinium bromide
KG 1044
RS-3-methyl-1-[1-(methoxycarbonyl)-1-(4-methoxyphenyl)methoxycarbonylmethyl]imidazolium octyl
sulphate
KG 1045
RS-[1-(butoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]pyridinium octyl
sulphate
KG 1046
RS-[1-(butoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]pyridinium
bis(trifluoromethanesulphonyl)imide
KG 1047
RS-3-methyl-1-[1-(methoxycarbonyl)-1-(4-trifluoromethylphenyl)methoxycarbonylmethyl]imidazolium
octyl sulphate
KG 2000
RS-2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) methyl acetate, chloride salt
KG 2001
RS-2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) methyl acetate, octylsulphate salt
KG 2002
RS-2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) methyl acetate,
bis(trifluoromethanesulphonyl)imide salt
KG 2003
RS-2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) butyl acetate, chloride salt
KG2004
RS-2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) butyl acetate, octylsulphate salt
KG2005
RS-2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) butyl acetate,
bis(trifluoromethanesulphonyl)imide salt
KG2006
RS-2-(3,4-methylendioxyphenyl)-2-(3-methylimidazolium) methyl acetate, chloride salt
KG2007
RS-2-(3,4-methylendioxyphenyl)-2-(3-methylimidazolium) methyl acetate, octylsulphate salt
KG2008
RS-2-(3,4-methylendioxyphenyl)-2-(3-methylimidazolium) methyl acetate,
bis(trifluoromethanesulphonyl)imide salt
KG 2011
RS-3-methyl-1-[1-(methoxycarbonyl)-1-(3,4-
methylenedioxyphenyl)methoxycarbonylmethyl]imidazolium chloride
KG2012
RS-2-(3,4-dihydroxyphenyl)-2-(3-methylimidazolium) methyl acetate, chloride salt
KG2013
RS-2-(3,4-dimethoxyphenyl)-2-(pyridinium) methyl acetate, chloride salt
KG2014
RS-2-(3,4-dimethoxyphenyl)-2-(pyridinium) methyl acetate, octylsulphate salt
KG2015
RS-2-(3,4-methylendioxyphenyl)-2-(pyridinium) methyl acetate, bromide salt
KG2016
RS-[1-(methoxycarbonyl)-1-(3,4-methylenedioxyphenyl)methoxycarbonylmethyl]pyridinium bromide
KG 2017
S-3-methyl-1-[1-(methoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium bromide
KG 2018
S-3-methyl-1-[1-(methoxycarbonyl)-1-methylmethoxycarbonylmethyl]imidazolium
bis(trifluoromethanesulphonyl)imide
[0207] Particularly preferred lactate based CILs having the counter anion OctOSO 3 − are those selected from the group comprising:
KG162, (RS) 3-Methyl-1-(1-methyl-1-methoxycarbonyl)methylimidazolium octylsulfate. KG163, (R) 3-Methyl-1-(1-methyl-1-methoxycarbonyl)methylimidazolium octylsulfate, KG166, (RS) 3-Methyl-1-(1-methyl-1-propoxycarbonyl)methylimidazolium octylsulfate, KG167, (R) 3-Methyl-1-(1-methyl-1-propoxycarbonyl)methylimidazolium octylsulfate, KG170, (RS) 3-Methyl-1-(1-methyl-1-pentoxycarbonyl)methylimidazolium octylsulfate, KG171, (R) 3-Methyl-1-(1-methyl-1-pentoxycarbonyl)methylimidazolium octylsulfate, KG172, (RS) 3-Methyl-1-(1-methyl-1-(2-ethoxyethoxy)carbonyl)methylimidazolium octylsulfate and KG173 (R) 3-Methyl-1-(1-methyl-1-(2-ethoxyethoxy)carbonyl)methylimidazolium octylsulfate.
[0216] Particularly preferred mandelate based CILs having the counter anion OctOSO 3 − are those selected from the group consisting of:
KG301, (R) 3-Methyl-1-(1-phenyl-1-(2-ethoxyethoxy)carbonyl)methylimidazolium octylsulfate, KG302, (S) 3-Methyl-1-(1-phenyl-1-pentoxycarbonyl)methylimidazolium octylsulfate, KG303, (R) 3-Methyl-1-(1-phenyl-1-pentoxycarbonyl)methylimidazolium octylsulfate, KG304, (RS) 3-Methyl-1-(1-phenyl-1-pentoxycarbonyl)methylimidazolium octylsulfate, KG305, (S) 3-Methyl-1-(1-phenyl-1-(2-ethoxyethoxy)carbonyl)methylimidazolium octylsulfate, KG306, (S) 3-Methyl-1-(1-phenyl-1-butoxycarbonyl)methylimidazolium octylsulfate and KG308, (RS) 3-Methyl-1-(1-phenyl-1-butoxycarbonyl)methylimidazolium octylsulfate.
[0223] In a related aspect of the present invention a compound of the invention may be used as an ionic liquid. In one embodiment, there is provided an ionic liquid composition comprising at least one of the compounds of the invention described herein. In a preferred embodiment, the compounds of the invention as described herein may be used as an ionic liquid solvent.
[0224] Particularly preferred is use in a process selected from the group consisting of a chemical reaction, a biomass dissolution and a biofuel preparation. Where use is in biomass dissolution, then it is preferred that the biomass dissolution is a cellulose dilution.
[0225] In a preferred embodiment, the compounds of the invention may be used as a solvent or a co-solvent, a catalyst or a co-catalyst, or electrolyte in a solar cell for the purpose of solar energy conversion.
[0226] In a preferred embodiment, the CIL compounds may be mixed with at least one achiral ILs in any ratio desired and may award favourable properties on the mixture when used as a solvent with regards to reaction stereoinduction, selectivity and/or conversion.
[0227] In a preferred embodiment still, the chiral ionic liquids compounds of the invention may be used as a solvent or a co-solvent, a catalyst or a co-catalyst for a chemical reaction, the reaction being selected from the group consisting of enzymatic and biocatalytic reactions, organocatalytic reactions, neutralizations, acidifications, basifications, oxidations, reductions, hydrogenation reactions, radical reactions, electrophilic additions, electrophilic substitutions, nucleophilic additions, nucleophilic substitutions, rearrangements, pericyclic reactions, metathesis reactions and reduction of an aromatic system. Particularly preferred are hydrogenation reactions, such as olefin hydrogenation reactions and reactions involving the reduction of an aromatic system.
[0228] Pericyclic reactions include Diels-Alder and Ene reactions. Organocatalytic reactions include Mannich, aza-Mannich and aldol reactions.
[0229] Thus the compounds of the invention are advantageous since they are alternative green solvents which may be used in organic reactions, such as hydrogenation reactions. Of particular interest are CILs of the invention, which may be used in hydrogenation of compounds such as trans-cinnamaldehyde or benzyl cinnamate using the commercially available Pd/C catalyst and which will allow superior control of the reactant conversion and product selectivity.
[0230] In an embodiment involving hydrogenation reactions, the hydrogenation reaction may be carried out homogenously or heterogeneously.
[0231] In an embodiment where the hydrogenation reaction is carried out heterogeneously, the heterogenous hydrogenation may carried out in the presence of hydrogen gas and palladium supported on carbon or in the presence of hydrogen gas and platinum supported on carbon.
[0232] On the other hand where the hydrogenation reaction is carried out homogeneously, the hydrogenation reaction may be carried out in the presence of Wilkinson's catalyst, (NB Adams' catalyst is heterogeneous) a Taniaphos SL-T001-1/bis(norbornadiene)rhodium(I) tetrafluoroborate system or Rh DiPAMP-based chiral catalysts. In an alternative preferred embodiment, the hydrogenation reaction is the selective reduction of any of Z-methyl-α-(N-acetamido) cinnamate, dimethyl itaconate, tiglic acid, α-acetamido cinnamic acid, α-methyl-trans-cinnamaldehyde or α-acetamido acrylate substrates.
[0233] In a preferred hydrogenation reaction, the compounds of the invention are used as CILs in the selective reduction of the alkene bond of α-acetamido acrylate substrates using Rh DiPAMP-based chiral catalysts. In a preferred hydrogenation reaction, the compounds of the invention are used as CILs in the selective reduction of the alkene bond conjugated to the carbonyl group of benzyl cinnamate using hydrogen gas and palladium supported on carbon.
[0234] In a particularly preferred embodiment, the CIL used is a mandelate based IL, used as an additive with an achiral IL in the homogenous hydrogenation of an olefin substrate. In this type of reaction the preferred substrate is dimethyl itaconate.
[0235] In an embodiment involving reduction of an aromatic system, it is preferred that the reaction is carried out under 1 atmosphere of hydrogen using a Taniaphos catalyst system or a Rh DiPAMP-based catalyst system. In this embodiment, it is preferred that the aromatic system to be reduced is that of a substrate such as Z-methyl-α-(N-acetamido) cinnamate. In this system, advantageously, asymmetry is induced in the products.
[0236] Alternative preferred reactions, in which the compounds of the invention may be suitably used as CILs, include metathesis reactions and pericyclic reactions.
[0237] In a related aspect of the invention, the compounds described herein may be used as a chiral reagent in asymmetric synthesis. In particular, it is preferred that such chiral reagents are used in reactions involving the substrate Z-methyl-α-(N-acetamido) cinnamate.
[0238] In a further related aspect, the compounds may be used as a chromatographic separation reagent. Preferably, with regard to this aspect, in a preferred embodiment, the chromatographic separation reagent may be used as a stationary phase. Such stationary phase may be suitably used in an SPE column, a HPLC column, a GC column, a TLC plate or on a HPTLC plate.
[0239] Alternatively, the compounds may be added to mobile phase for use with chromatographic stationary phases.
[0240] Examples of CILs either as racemic mixtures, or single enantiomers have been prepared. CILs incorporating mandelic acid have been prepared as racemic mixtures, or the R or S enantiomer. A synthetic route that does not led to epimerisation of the chiral centre can be used for the stereoselective synthesis of a CIL, if demonstrated to be successful for the preparation of the racemate. Starting from the optically pure alpha-hydroxycarboxylic acid, either enantiomer of the CIL can be prepared.
[0241] For synthetic routes where epimerisation may occur (e.g. nucleophilic substitution alpha to aryl and carboxylic groups), chiral resolution of the racemic mixture will be required to obtain the optically pure chiral ionic liquid. Chiral resolution via crystallization of diastereomeric salts, or via enzymatic methods, or via chiral HPLC methods are preferred.
BRIEF DESCRIPTION OF THE DRAWINGS
[0242] FIG. 1 : Mandelate and Lactate CILs;
[0243] FIG. 2 : Library of CILs;
[0244] FIG. 3 : Enantioselective Hydrogenation of Methyl α-acetoamidocinnamate;
[0245] FIG. 4 : Hydrogenation of Methyl α-acetoamidocinnamate in CIL derived from (S)-methyl mandelate as NTf 2 salt [KG 94];
[0246] FIG. 5 : Hydrogenation of Methyl α-acetoamidocinnamate in CIL derived from (R)-methyl mandelate as NTf 2 salt [KG 93];
[0247] FIG. 6 : Synthetic Route to CILs;
[0248] FIG. 7 : Graphical Representation of Biodegradation of Chiral Lactate—derived Octylsulfates (CO 2 Headspace Test) over the Course of 28 days (Sodium dodecylsulfate [SDS] is taken as a reference compound);
[0249] FIG. 8 : Graphical Representation of Biodegradation of Chiral Mandelate—derived Octylsulfates (CO 2 Headspace Test) over the Course of 28 days (Sodium dodecylsulfate [SDS] is taken as a reference compound);
[0250] FIG. 9 : Synthetic route to KG 2000-2002;
[0251] FIG. 10 : Synthetic route to KG 2003-2005;
[0252] FIG. 11 : Synthetic Route to KG 2006-2008 and
[0253] FIG. 12 : Synthesis of 3,4-dimethoxy methyl mandelate based ionic liquid KG 2013-2014.
DETAILED DESCRIPTION OF THE INVENTION
[0254] Ionic liquids based on chiral alpha hydroxy carboxylic (mandelic 1 and lactic 2) acids were prepared by acylating the free hydroxyl group of an ester of the chiral carboxylic acid with bromoacetyl bromide and then in the next step reacting the bromoalkyl linker with 3-N-methylimidazole or pyridine to give a chiral bromide salt. The bromide may then be exchanged with various counter ions such as ditriflimide, octylsulfate and dicyanoamide to give ionic liquids. The octyl sulphate imidazolium chiral ionic liquids tested to date are biodegradable and have low antimicrobial and antifungal toxicity. The octyl sulphate pyridinium chiral ionic liquids tested to date have low antimicrobial and antifungal toxicity and are expected to have good biodegradability. NTf 2 chiral ionic liquids have lower viscosity.
[0255] Novel chiral ILs based on chiral carboxylic acids, such as, mandelic 1 and lactic acids 2 have been investigated as solvents for organic transformations, such as, for the hydrogenation of olefins (a green process of major importance to the pharmaceutical industry, especially in asymmetric processes) including prochiral examples, such as (Z) methyl-α-(N-acetamido) cinnamate ( FIG. 4 ). Diels-Alder, Ene reactions, and other pericyclic processes are also potential applications for the CILs described, as are organocatalytic reactions, such as Mannich, aza-Mannich, and aldol reactions, such that they are compatible with the ester linkages in the CILs. A variety of side-chains have been incorporated into the ILs (including both glycol ethers and alkyl groups) and both racemic and enantiopure mandelic and lactic acid were used as precursors for the Ils ( FIG. 1 ). 2-Phase systems were demonstrated between the ILs and solvents such as toluene and ether, but interestingly a triphasic system was found to form between methylimidazolium mandelic acid derived IL 1 (racemic CIL, butyl ester/ditriflimide anion), water and toluene, which can provide advantages in reactions and also in separation science if products can be partitioned between the 3 phases preferentially (providing an alternative to 3-phases systems based on fluorous solvents such as the environmentally hazardous benzotrifluoride (trifluorotoluene) (D.P. Curran).
[0256] The synthesis of a new library of functionalised mandelate CILs (see table M, KG 837-884, for a specific example, see data provided for KG 852) with the potential to interact with metals or catalysts via oxygen substituents on the aromatic ring ( FIG. 2 ) was undertaken. By varying R (methyl, butyl, hydrogen, phosphine), R 1 (methyl, butyl), R 2 (methyl, butyl) and X (OctOSO 3 , NTf 2 , N(CN) 2 ), a large library of new chiral ionic liquids with different properties is now available. The compounds 3,4-dihydroxymandelic acid and butyl 3,4-dimethoxymandelate 3 were synthesized by the inventors and together with commercially-available 3,4-methylenedioxymandelic 4 acid ( FIG. 3 ) and derivates of same mean that these synthetic derivatives are suitable intermediates to expand the CIL library.
Detailed Experimental Methods
Preparation of ILs
[0257] A simple method to synthesize the family of ionic liquids has been developed which produced the ILs in good yield for each step. A typical reaction scheme for synthesis of the chiral ILs is shown in FIG. 6 . Referring to FIG. 6 , in cases where the chiral centre in the IL is prone to racemisation under basic conditions, the alumina-catalysed esterification of Yadav, at room temperature, is preferred for the first step (esterification), rather than the use of triethylamine in DCM at −78° C. In brief, a bromoester alkylating agent is made from the chiral alcohol of interest (ILs with amide side chains or ILs with thioester side chains can be typically prepared by use of a haloamide or halothioester alkylating agent respectively). The bromoester is then reacted with the imidazole or pyridine of interest to form the imidazolium bromide salt or pyridinium bromide salt respectively. Preparation of alkylating reagents where the alcohol group of the alpha-hydroxyester has been converted to a chloride, was accomplished via treatment with thionyl chloride. Nucleophilic substitution by the imidazole or pyridine of interest leads to imidazolium chloride salt or pyridinium chloride salt respectively. An alternative one-pot method has been developed where the alcohol group of the mandelic acid ester is converted to the halide, via thionyl bromide or thionyl chloride, in the presence of the Nitrogen heterocycle (methylimidazole). The imidazolium halide salts were isolated in good yield by this one pot method. A large range of these types of ILs, possessing different properties have been made through the final synthetic anion exchange step from halide to different salts by reaction with LiNTf 2 , or NaOctOSO 3 .
Step I: Preparation of Alkylating Agent
[0258] Typically, the first step (i) is the preparation of the alkylating agent obtained by reaction between the bromoacetyl bromide and different alcohols, amines or thiols. The reaction involving bromoacetyl bromide and alcohols was performed under a nitrogen atmosphere at −78° C. for 3 hours. After purification by distillation the corresponding bromoester in a yield ranging from 62-88% was obtained. This reaction has been performed successfully on a broad range of scales from 10 mmol to 0.5 mol. The bromo ester derivatives were typically prepared in pure form on a large scale without the need for purification by column chromatography.
Step I: Alternative Preparation of Alkylating Agent
[0259] Typically, the first step (i) is the preparation of the alkylating agent obtained by reaction between the bromoacetyl bromide and different alcohols, amines or thiols. The reaction involving bromoacetyl bromide and alcohols was performed in the absence of solvent and promoted by neutral alumina. The reaction required typically 1 hour to reach completion, cooling with an ice bath during addition, then warming to RT without any requirement of an inert atmosphere, according to the procedure of Yadav. After purification by absorption of the crude reaction mixture onto excess solid NaHCO 3 and standing overnight, the solid was washed with toluene, filtered and the filtrate evaporated to give the corresponding bromoester in a yield typically around 88%. This reaction has been performed successfully on a broad range of scales using at least 2 equivalents of bromoacetyl bromide with the different alcohols.
[0260] The bromides prepared by this method are pure enough to carry through to the subsequent imidazole alkylation without the need for purification by column chromatography.
[0000] Preparation of (R)-methyl 2-bromoacetoxy-2-phenylacetate
[0261] To a stirred solution of DCM, (R)-methyl mandelate (1.48 g, 8.92 mmol), and triethylamine (2.02 g, 20.0 mmol), in DCM (30 ml) under a nitrogen atmosphere at −78° C. was added dropwise bromoacetyl bromide (3.03 g, 15.0 mmol). After stirring at −78° C. for 5 h, the reaction mixture was allowed warm up to −20° C. and quenched by addition of water (20 mL). The organic phase was washed with distilled water (3×20 mL), saturated ammonium chloride (3×20 mL), saturated sodium bicarbonate (3×20 mL) and brine (2×20 mL). The organic phase was then dried over magnesium sulfate, filtered and solvents removed via rotary evaporation to yield a crude product in 84% yield (2.13 g, 7.42 mmol). Column chromatography was performed on the crude product (mobile phase: DCM:Hexane, 50:50) to give a pale yellow liquid at RT in 73% yield (1.85 g, 6.45 mmol).
[0000] Alternative Preparation of (R)-methyl 2-bromoacetoxy-2-phenylacetate
[0262] To methyl (R)-mandelate (8.3 g, 150 mmol), and neutral alumina [e.g. Aldrich type WN-3] (17 g, 167 mmol) cooled with an ice-bath was added bromoacetyl bromide (44 mL, 500 mmol). The ice bath was removed and after 1 h standing at RT, the reaction mixture was poured onto solid NaHCO 3 (117 g) in a glass filter funnel, with a cotton wool plug (effervescence). After standing overnight, the solid was washed with toluene until 200 ml of filtrate had been collected. The volatiles were removed via rotary evaporation to yield a crude product in 88% yield. This crude product was sufficiently pure to carry through to the next step.
[0263] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 7.41-7.34 (m, 5H), 5.91 (s, 1H), 3.91 (d, J=1.6 Hz, 2H), 3.66 (s, 3H)
[0264] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 168.60 (CO), 166.61 (CO), 133.00 (ArC), 129.60 (ArC), 128.94 (ArC), 127.68 (ArC), 75.68 (COO), 52.86 (OCH3), 25.32 (CH2)
[0000] Preparation of alkyl-2-chloro-(3,4-dimethoxyphenyl)acetates
[0265] The mandelic acid derivative is converted to the mandelic acid ester then the alcohol group transformed to a chloride by treatment with thionyl chloride.
[0000] Synthesis of butyl 3,4-dimethoxy mandelate
[0000]
Synthesis:
[0266] A solution of 3,4-dimethoxy mandelic acid (7.501 g, 35.3 mmol) in butanol (15 mL) was stirred at room temperature. Thionyl chloride (3.6 mL, 49.3 mmol) was added drop wise. Reaction was monitored by TLC and stirred for 2 h. Reaction was quenched by addition of water (50 mL) and product was extracted with DCM (8×25 mL). Organic phase was dried over anhydrous magnesium sulphate and coevaporated ten times with hexane to remove remaining butanol. Pure product as yellow oil in 80.2% yield (7.601 g, 28.4 mmol) was obtained.
Product Characterization:
[0267] Molecular formula: C 14 H 20 O 3
[0268] Molecular weight: 268.3 g/mol
[0269] 1 H NMR (400 Hz, CDCl 3 ) δ ppm 7.04-6.92 (m, 2H), 6.83 (d, 1H, J=8.0 Hz), 5.09 (s, 1H), 4.21-4.10 (m, 2H), 3.87 (s, 3H), 3.86 (s, 3H), 1.62-1.52 (m, 2H), 1.32-1.21 (m, 2H), 0.85 (t, 3H, J=8.0 Hz)
[0000] Synthesis of butyl-2-chloro-(3,4-dimethoxyphenyl)acetate:
[0000]
Synthesis:
[0270] A solution of 3,4-dimethoxy butyl mandelate (3.018 g, 11.26 mmol) in DCM (50 mL) was stirred at 0° C. Thionyl chloride (0.82 mL, 11.26 mmol) was added drop wise followed by addition of triethylamine (1.56 mL, 11.26 mmol). Reaction was monitored by TLC and stirred for 4 h. The product was then washed with distilled water (3×20 mL). The organic phase was dried over anhydrous magnesium sulphate, filtrated and solvent removed on the rotary evaporator. Flash column chromatography was performed on the crude product (mobile phase, DCM) to yield a colorless oil in 77.9% yield (2.513 g, 8.77 mmol).
Product Characterization:
[0271] Molecular formula: C 14 H 19 ClO 4
[0272] Molecular weight: 286.8 g/mol
[0273] 1 H NMR (400 Hz, CDCl 3 ) δ ppm 7.04 (d, 1H, J=2.2 Hz), 7.01 (dd, 1H, J=8.3, 2.2 Hz), 6.82 (d, 1H, J=8.3 Hz), 5.30 (s, 1H), 4.22-4.11 (m, 2H), 3.89 (s, 3H), 3.88 (s, 3H), 1.60 (m, 2H), 1.31 (tq, 2H, J=7.5, 7.5 Hz), 0.88 (t, 3H, J=7.4 Hz)
[0274] 13 C δ ppm (100 Hz, CDCl 3 ) 168.59 (CO), 149.81 (ArC), 149.16 (ArC), 128.15 (ArC), 120.77 (ArC), 110.77 (ArC), 110.60 (ArC), 66.24 (OCH 2 ), 59.25 (CH), 55.90 (OCH 3 ), 55.90 (OCH 3 ), 30.38 (CH 2 ), 18.92 (CH 2 ), 13.60 (OCH 3 ).
Experimental Methods for Preparation of Bromide, Chloride, NTf 2 and OctOSO 4 Ionic Liquids
[0275] Representative Procedure for the Preparation of Chiral Bromide Salts (RS-3-methyl-1-(methylmandelylcarbonylmethyl)imidazolium bromide) (KG89)
[0000]
Synthesis:
[0276] To a stirred solution of 1-methylimidazole (18.0 mmol, 1.48 g) in diethyl ether (100 mL) at −15° C. under a nitrogen atmosphere was added drop wise RS-methyl mandelyl bromoacetate (20.0 mmol, 5.74 g). The reaction mixture was stirred vigorously at −15° C. for 4 h, then at RT overnight. The ether top phase was decanted and the product washed with ether (3×10 mL), the solvent removed on the rotary evaporator and dried under high vacuum for 8 h to give an off-white powder at RT in 94% yield (6.90 g, 18.7 mmol).
Product Characterization:
[0277] Molecular formula C 15 H 17 BrN 2 O 4
[0278] Molecular weight 369 g/mol
[0279] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 10.25 (s, 1H, H2), 7.61 (s, 1H, H3), 7.47 (s, 1H, H4), 7.45-7.50 (m, 5H, H's 9-13), 6.02 (s, 1H, H7), 5.81 (d, J=17.6 Hz, 1H, H5), 5.56 (d, J=17.6 Hz, 1H, H5), 4.05 (s, 3H, H1), 3.72 (s, 3H, H15)
[0280] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 168.46 (CO), 165.76 (CO), 138.56 (NCH 2 N), 132.29 (ArC), 129.88 (ArC), 129.06 (ArC), 127.86 (ArC), 123.72 (NCH 2 ), 123.05 (NCH 2 ), 76.23 (OCH), 53.09 (NCH 2 ), 50.22 (OCH 3 ), 36.95 (NCH 3 )
[0281] MP (° C.) 140-142
[0282] IR (KBr disc) (cm −1 ) 3482, 3393, 3088, 1762, 1744, 1576, 1565, 1453, 1436, 1380, 1285, 1231, 1213, 1174, 1019
[0283] MS m/z, Found 289.1185 [M-Br—] + , Calcd. C 18 H 23 N 2 O 4 289.1188
[0284] MS m/z, 289.1 [M-Br − ] + ; MS: m/z, 78.9 [Br − ]
[0000] R-3-Methyl-1-(methylmandelylcarbonylmethyl)imidazolium bromide (KG90)
[0000]
Synthesis:
[0285] The title compound (a beige solid) was prepared from R-mandelate bromoacetate (11.48 g, 40.0 mmol) and 1-methylimidazole (3.12 g, 38.0 mmol) according to the general procedure in 93% yield (12.97 g, 35.2 mmol).
Product Characterization:
[0286] Molecular formula C 15 H 17 BrN 2 O 4
[0287] Molecular weight 369 g/mol
[0288] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 10.03 (s, 1H), 7.59 (s, 1H), 7.48 (s, 1H), 7.37-7.31 (m, 5H), 5.93 (s, 1H), 5.70 (d, J=17.6 Hz, 1H), 5.50 (d, J=17.6 Hz, 1H), 3.96 (s, 3H), 3.63 (s, 3H)
[0289] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 168.50, 165.88, 138.22, 132.35, 129.84, 129.05, 127.85, 123.76, 123.28, 76.17, 53.09, 50.18, 36.94
[0290] MP (° C.) 99-101
[0291] IR (KBr disc) (cm −1 ) 3477, 3393, 3090, 1761, 1746, 1577, 1564, 1452, 1432, 1380, 1285 1233, 1218, 1176, 1022
[0292] MS m/z, Found 289.1180 [M-Br—] + , Calcd. C 18 H 23 N 2 O 4 289.1188
[0293] MS m/z, 289.1 [M-Br − ] + ; MS: m/z, 78.9 [Br − ]
[0294] [α] D 20 -62.7 g (0.57 c, CHCl 3 )
[0000] S-3-Methyl-1-(methylmandelylcarbonylmethyl)imidazolium bromide (KG91)
[0000]
Synthesis:
[0295] The title compound was prepared from S-mandelate bromoacetate (10.05 g, 35.0 mmol) and 1-methylimidazole (2.62 g, 32.0 mmol) according to the general procedure in 78% yield (10.10 g, 27.4 mmol)
Product Characterization:
[0296] Molecular formula C 15 H 17 BrN 2 O 4
[0297] Molecular weight 369 g/mol
[0298] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 10.16 (s, 1H), 7.53 (t, J=1.8 Hz, 1H), 7.39 (t, J=1.8 Hz, 1H), 7.38-7.32 (m, 5H), 5.94 (s, 1H), 5.73 (d, J=18.0 Hz, 1H), 5.49 (d, J=18.0 Hz, 1H), 3.98 (s, 3H), 3.66 (s, 3H)
[0299] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 168.48, 165.85, 138.34, 132.23, 129.85, 129.05, 127.85, 123.76, 123.21, 76.19, 53.08, 50.20, 15.29
[0300] MP (° C.) 97-99
[0301] IR (KBr disc) (cm −1 ) 3481, 3393, 3086, 2949, 1763, 1744, 1577, 1566, 1452, 1434, 1380, 1285, 1231, 1213, 1174 1018
[0302] MS m/z, Found 289.1181 [M-Br—] + , Calcd. C 13 H 23 N 2 O 4 289.1188
[0303] MS m/z, 289.1 [M-Br − ] + ; MS: m/z, 78.9 [Br − ]
[0304] [α] D 20 +63.8° (0.59 c, CHCl 3 )
[0305] Representative Procedure for the Preparation of Chiral NTf 2 Salts (RS-3-Methyl-1-(methylmandelylcarbonylmethyl)imidazolium NTf 2 ) (KG92)
[0000]
Synthesis:
[0306] A flask was charged with RS-3-methyl-1-(methyl mandelyl carbonylmethyl) imidazolium bromide (0.67 g, 1.81 mmol) and distilled water (10 mL). LiNTf 2 (0.86 g, 3.00 mmol) was added in one portion and the suspension was stirred vigorously for overnight at RT. The top aqueous layer was removed and the IL was washed with distilled water (3×5 mL). The solvent was then removed on the rotary evaporator and under high vacuum for 5 h to give an orange crystalline material at RT in 92% yield (0.95 g, 1.67 mmol)
Product Characterization:
[0307] Molecular formula C 17 H 17 F 6 N 3 O 8 S 2
[0308] Molecular weight 569 g/mol
[0309] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 8.73 (s, 1H, H1), 7.32 (broad s, 5H, H's 9-13), 7.31 (s, 1H, H3), 7.22 (s, 1H, H4), 5.93 (s, 1H, H7), 5.08 (s, 2H, H5), 3.84 (s, 3H, H1), 3.62 (s, 3H, H15)
[0310] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 168.42 (COO), 165.33 (COO), 137.68 (NCHN), 132.25 (ArC), 129.91 (NCH 2 ), 129.05 (NCH 2 ), 127.79 (ArC), 123.77 (q, J=319 Hz, 2CF 3 ), 76.36 (OCH), 53.02 (NCH 2 ), 49.80 (OCH 3 ), 36.56 (NCH 3 )
[0311] MP (° C.) 73-75
[0312] IR (KBr disc) (cm −1 ) 3470, 3379, 2099, 1750, 1571, 1566, 1459, 1453, 1451, 1390, 1197, 1127
[0313] MS m/z, 289.1 [M-NTf 2 − ] + ; MS: m/z, 280.0 [NTf 2 − ]
[0000] RS-3-Methyl-1-(ethylmandelylcarbonylmethyl)imidazolium NTf 2 (KG 813)
[0000]
Synthesis:
[0314] The title compound was prepared from RS-3-methyl-1-(ethyl mandelyl carbonyl methyl) imidazolium bromide (0.96 g, 2.60 mmol) and LiNTf 2 (1.00 g, 3.50 mmol) according to the general procedure in 95% yield (1.43 g, 2.45 mmol)
Product Characterization:
[0315] Molecular formula C 13 H 20 F 6 N 3 O 8 S 2
[0316] Molecular weight 583 g/mol
[0317] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 8.79 (s, 1H), 7.37-7.35 (m, 5H), 7.31 (t, J=1.8 Hz, 1H), 7.22 (t, J=1.8 Hz, 1H), 5.91 (s, 1H), 5.10 (d, J=18 Hz, 2H), 4.20-4.03 (m, 2H), 3.87 (s, 3H), 1.13 (t, J=7.2 Hz, 3H)
[0318] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 167.89, 165.27, 137.84, 132.29, 129.86, 129.02, 127.78, 123.71, 123.25, 121.27 (q, J=320 Hz, 2C), 76.52, 62.33, 49.88, 36.64, 13.91
[0319] IR (thin film on salt plate) (cm −1 ) 3167, 3120, 2960, 2927, 2860, 1751, 1566, 1559, 1540, 1495, 1457, 1354, 1198, 1136
[0320] MS m/z, 303.1 [M-NTf 2 − ] + ; MS: m/z, 280.0 [NTf 2 ]
[0000] R-3-Methyl-1-(ethylmandelylcarbonylmethyl)imidazolium NTf 2 (KG 829)
[0000]
Synthesis:
[0321] The title compound was prepared from R-3-methyl-1-(ethyl mandelyl carbonyl methyl) imidazolium bromide (1.03 g, 2.70 mmol) and LiNTf 2 (0.86 g, 3.00 mmol) according to the general procedure in 89% yield (1.41 g, 2.41 mmol)
Product Characterization:
[0322] Molecular formula C 13 H 20 F 6 N 3 O 8 S 2
[0323] Molecular weight 583 g/mol
[0324] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 8.67 (s, 1H), 7.36-7.29 (m, 6H), 7.24 (t, J=1.6 Hz, 1H), 5.88 (s, 1H), 5.05 (s, 2H), 4.16-4.11 (m, 2H), 3.81 (s, 3H), 1.10 (t, J=7.2 Hz, 3H)
[0325] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 167.92, 165.38, 137.49, 132.40, 129.81, 128.99, 127.74, 123.74, 123.46, 121.27 (q, J=320 Hz, 2C), 76.46, 62.29, 49.72, 36.47, 13.84
[0326] MP (° C.) 44-46
[0327] IR (KBr disc) (cm −1 ) 3156, 3099, 3007, 1761, 1735, 1579, 1568, 1500, 1456, 1430, 1371, 1356, 1279, 1187, 1132, 1051
[0328] MS m/z, 303.1 [M-NTf 2 ] + ; MS: m/z, 280.0 [NTf 2 − ]
[0329] [α] D 20 −53.7° (0.5 c, CHCl 3 )
[0000] S-3-Methyl-1-(ethylmandelylcarbonylmethyl)imidazolium NTf 2 (KG 821)
[0000]
Synthesis:
[0330] The title compound was prepared from S-3-methyl-1-(ethyl mandelyl carbonyl methyl) imidazolium bromide (0.96 g, 2.50 mmol) and LiNTf 2 (0.86 g, 3.00 mmol) according to the general procedure in 98% yield (1.42 g, 2.44 mmol)
Product Characterization:
[0331] Molecular formula C 13 H 20 F 6 N 3 O 8 S 2
[0332] Molecular weight 583 g/mol
[0333] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 8.72 (s, 1H), 7.36-7.32 (m, 5H), 7.30 (t, J=1.8 Hz, 1H), 7.23 (t, J=1.8 Hz, 1H), 5.89 (s, 1H), 5.07 (s, 2H), 4.18-4.02 (m, 2H), 3.85 (s, 3H), 1.12 (t, J=7.0 Hz, 3H)
[0334] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 167.92, 165.34, 137.64, 132.36, 129.83, 129.01, 127.76, 123.74, 123.38, 121.27 (q, J=320 Hz, 2C), 76.49, 62.31, 49.80, 36.55, 13.88
[0335] MP (° C.) 44-46
[0336] IR (KBr disc) (cm −1 ) 3165, 3099, 2998, 2963, 1759, 1735, 1579, 1564, 1496, 1452, 1434, 1356, 1279, 1198, 1134, 1044
[0337] MS m/z, 303.1 [M-NTf 2 − ] + ; MS: m/z, 280.0 [NTf 2 ]
[0338] [α] D 20 +54.7 g (0.7 c, CHCl 3 )
[0339] Representative Procedure for the Preparation of Chiral OctOSO 3 Salts (RS-3-Methyl-1-(methylmandelylcarbonylmethyl)imidazolium OctOSO 3 ) (KG 86)
[0000]
Synthesis:
[0340] To a stirred solution of RS-3-methyl-1-(methyl mandelyl carbonyl methyl) imidazolium bromide (2.50 mmol, 0.92 g) in distilled water (20 mL) was added in one portion sodium octyl sulfate (2.60 mmol, 0.60 g). The mixture was left stirring overnight, then the water was evaporated on the rotary evaporator. The remaining product was dissolved in DCM (10 mL) and washed with water (2×2 mL). The product was then dried on the rotary evaporator and under high vacuum for 8 h to give a pale brown solid at RT in 71% yield (0.89 g, 1.78 mmol)
Product Characterization:
[0341] Molecular formula C 23 H 34 N 2 O 8 S 2
[0342] Molecular weight 498 g/mol
[0343] 1 H NMR (400 MHz, CDCl 3 ) 5 ppm 9.24 (s, 1H, H2), 7.48 (t, J=1.6 Hz, 1H, H3), 7.42 (t, J=1.6 Hz, 1H, H4), 7.36-7.30 (m, 5H, H's 9-13), 5.91 (s, 1H, H7), 5.32 (d, J=17.8 Hz, 1H, H5), 5.24 (d, J=17.8 Hz, 1H, H5), 3.88-3.83 (m, 5H, H's 15 and 16), 3.61 (s 3H, H1), 1.52 (tt, J=7.2 Hz, 7.2 Hz, 2H, H17), 1.22-1.12 (m, 10H, H's 18-22), 0.81 (t, J=7.2 Hz, 3H, H23)
[0344] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 167.50 (COO), 165.11 (COO), 137.55 (NCHN), 131.54 (ArC), 128.68 (ArC), 127.93 (ArC), 126.75 (ArC), 122.81 (NCH 2 ), 122.45 (NCH 2 ), 75.08 (CH), 66.75 (OCH 3 ), 51.89 (OCH 2 ), 48.65 (NCH 2 ), 35.40 (CH 2 ), 30.78 (NCH 3 ), 28.44 (CH 2 ), 28.31 (CH 2 ), 28.22 (CH 2 ), 24.81 (CH 2 ), 21.62 (CH 2 ), 13.10 (CH 3 )
[0345] MP (° C.) 61-62
[0346] IR (KBr disc) (cm −1 ) 3159, 3125, 2963, 2932, 2850, 1740, 1552, 1531, 1495, 1454, 1399, 1210, 1177
[0347] MS m/z, 289.1188 [M-OctOSO 3 − ] + ; MS: m/z, 209.1 [OctOSO 3 − ]
[0000] RS-3-Methyl-1-(ethylmandelylcarbonylmethyl)imidazolium OctOSO 3 (KG 307)
[0000]
Synthesis:
[0348] The title compound was prepared from RS-3-methyl-1-(ethyl mandelyl carbonyl methyl) imidazolium bromide (2.50 mmol, 0.94 g) and sodium octyl sulfate (2.60 mmol, 0.60 g) according to the general procedure in 92% yield (1.18 g, 2.30 mmol)
Product Characterization:
[0349] Molecular formula C 24 H 36 N 2 O 8 S 2
[0350] Molecular weight 512 g/mol
[0351] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 9.46 (s, 1H), 7.48 (t, J=1.6 Hz, 1H), 7.44-7.33 (m, 5H), 7.36 (t, J=1.6 Hz, 1H), 5.99 (s, 1H), 5.48 (d, J=18 Hz, 1H), 5.33 (d, J=18 Hz, 1H), 4.19-4.09 (m, 2H), 3.98 (s, 3H), 1.63 (m, 2H), 1.31-1.19 (m, 12H), 1.22 (t, J=7.0 Hz, 3H), 0.88 (t, J=7.0 Hz, 3H)
[0352] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 168.02, 165.93, 138.85, 132.50, 129.72, 128.58, 127.79, 123.62, 123.11, 76.29, 68.24, 62.22, 49.90, 36.67, 31.82, 29.39, 29.32, 29.25, 25.80, 22.66, 14.13, 13.97
[0353] IR (thin film on salt plate) (cm −1 ) 2958, 2927, 2857, 1748, 1559, 1539, 1495, 1452, 1401, 1202, 1176
[0354] MS m/z, 303.1 [M-OctOSO 3 − ] + ; MS: m/z, 209.1 [OctOSO 3 31 ]
[0000] R-3-Methyl-1-(ethylmandelylcarbonylmethyl)imidazolium OctOSO 3 (KG 401)
[0000]
Synthesis:
[0355] The title compound was prepared from R-3-methyl-1-(ethyl mandelyl carbonyl methyl)imidazolium bromide (2.50 mmol, 0.95 g) and sodium octyl sulfate (2.60 mmol, 0.60 g) according to the general procedure in 95% yield (1.22 g, 2.39 mmol)
Product Characterization:
[0356] Molecular formula C 24 H 36 N 2 O 8 S 2
[0357] Molecular weight 512 g/mol
[0358] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 9.46 (s, 1H), 7.39 (t, J=1.6 Hz, 1H), 7.34-7.24 (m, 5H), 7.28 (t, J=1.6 Hz, 1H), 5.90 (s, 1H), 5.41 (d, J=18 Hz, 1H), 5.25 (d, J=18 Hz, 1H), 4.13-3.98 (m, 2H), 3.90 (s, 3H), 1.54 (tt, J=7.2, 7.4 Hz, 2H), 1.21-1.13 (m, 12H), 1.13 (t, J=7.4 Hz, 3H), 0.80 (t, J=7.4 Hz, 3H)
[0359] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 168.03, 165.94, 138.95, 132.48, 129.73, 128.58, 126.55, 123.60, 123.07, 76.29, 68.08, 62.23, 49.88, 36.65, 31.83, 29.42, 29.33, 29.25, 25.81, 22.67, 14.14, 13.98
[0360] MP (° C.) 40-43
[0361] IR (KBr disc) (cm −1 ) 3160, 3120, 2956, 2927, 2856, 1751, 1565, 1559, 1539, 1495, 1456, 1403, 1205, 1177
[0362] MS m/z, 303.1 [M-OctOSO 3 − ] + ; MS: m/z, 209.1 [OctOSO 3 − ]
[0363] [α] D 20 −44.5° (0.8 c, Acetone)
[0000] S-3-Methyl-1-(ethylmandelylcarbonylmethyl)imidazolium OctOSO 3 (KG 300)
[0000]
Synthesis:
[0364] The title compound was prepared from S-3-methyl-1-(ethyl mandelyl carbonyl methyl)imidazolium bromide (2.60 mmol, 1.00 g) and sodium octyl sulfate (2.70 mmol, 0.63 g) according to the general procedure in 91% yield (1.21 g, 2.36 mmol)
Product Characterization:
[0365] Molecular formula C 24 H 36 N 2 O 8 S 2
[0366] Molecular weight 512 g/mol
[0367] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 9.40 (s, 1H), 7.35-7.28 (m, 6H), 7.26 (s, 1H), 5.90 (s, 1H), 5.38 (d, J=18
[0368] Hz, 1H), 5.22 (d, J=18 Hz, 1H), 4.10-4.02 (m, 2H), 3.90 (s, 3H), 1.54-1.49 (m, 2H), 1.17-1.12 (m, 15H), 0.80 (t, J=7.0 Hz, 3H)
[0369] 13 C NMR (100 MHz, CDCl 3 ) δ ppm 167.99, 165.90, 139.09, 132.48, 129.72, 128.97, 127.80, 123.56, 123.03, 76.31, 68.15, 62.21, 49.87, 36.63, 31.82, 29.41, 29.33, 29.25, 25.81, 22.66, 14.13, 13.97
[0370] MP (° C.) 38-40
[0371] IR (KBr disc) (cm −1 ) 3163, 3116, 2956, 2927, 2856, 1748, 1566, 1559, 1494, 1457, 1399, 1213, 1177
[0372] MS m/z, 303.1 [M-OctOSO 3 − ] + ; MS: m/z, 209.1 [OctOSO 3 − ]
[0373] [α] D 20 +43.8° (0.7 c, Acetone)
[0000] Preparation of 2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) butyl acetate, chloride salt (KG 2003):
[0000]
Synthesis:
[0374] To a stirred solution of butyl 2-chloro-2-(3,4-dimethoxyphenyl)acetate (2.004 g, 7.00 mmol) in diethyl ether (50 mL) at −15° C. under a nitrogen atmosphere 1-methylimidazole (0.48 mL, 6.09 mmol) was added drop wise. The reaction mixture was stirred at room temperature for 48 h. White precipitate and organic layer were collected and solvent was removed on the rotary evaporator. Product was washed with diethyl ether yielding white crystalline powder in 69.7% yield (1.565 g, 4.24 mmol).
Product Characterization:
[0375] Molecular formula: C 13 H 25 ClN 2 O 4
[0376] Molecular weight: 368.9 g/mol
[0377] 1 H NMR (400 Hz, CDCl 3 ) δ ppm 10.89 (s, 1H), 7.39 (s, 1H), 7.34 (d, 1H, J=2.0 Hz), 7.20 (s, 1H), 7.11 (s, 1H), 7.02 (dd, 1H, J=8.4, 1.6 Hz,), 6.87 (d, 1H, J=8.4 Hz), 4.30-4.18 (m, 2H), 4.03 (s, 3H), 3.92 (s, 3H), 3.88 (s, 3H), 1.63-1.57 (m, 2H), 1.28 (tq, 2H, J=7.4, 7.4 Hz), 0.87 (t, 3H, J=7.4 Hz)
[0378] 13 C δ ppm (100 Hz, CDCl 3 ) 167.95 (CO), 150.42 (ArC), 149.74 (ArC), 137.84 (ArC), 124.77 (ArC), 123.12 (ArC), 121.73 (ArC), 120.78 (ArC), 112.29 (ArC), 111.50 (ArC), 66.88 (OCH 2 ), 63.96 (NCH), 56.41 (OCH 3 ), 56.03 (OCH 3 ), 36.81 (NCH 3 ), 30.25 (CH 2 ), 18.88 (CH 2 ), 13.58 (CH 3 )
[0379] MS m/z, 333.10 [M-Cl − ] +
[0000] Synthesis of 2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) butyl acetate, Octylsulphate Salt (KG 2004):
[0000]
Synthesis:
[0380] To a stirred solution of 2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) butyl acetate, chloride salt (0.672 g, 1.82 mmol), in distilled water (10 mL) was added in one portion sodium octyl sulfate (0.440 g, 1.90 mmol). The mixture was left stirring overnight, then the water was evaporated on the rotary evaporator. The remaining product was dissolved in DCM (12 mL) and washed with water (2×2 mL). The product was then dried on the rotary evaporator and under high vacuum to give white crystals in 87.9% yield (0.866 g, 1.60 mmol).
Product Characterization:
[0381] Molecular formula: C 26 H 42 N 2 O 8 S
[0382] Molecular weight: 542.7 g/mol
[0383] 1 H NMR (400 Hz, CDCl 3 ) δ ppm 9.55 (s, 1H), 7.39 (dd, 1H, J=1.6, 1.2 Hz), 7.32 (dd, 1H, J=2.0, 1.6 Hz) 7.12 (d, 1H, J=2.0 Hz), 6.95 (dd, 1H, J=8.4, 2.0 Hz), 6.83 (d, 1H, J=8.4 Hz), 6.62 (s, 1H), 4.24-4.10 (m, 2H), 3.97 (t, 2H, J=7.0 Hz) 3.92 (s, 3H), 3.84 (s, 3H), 3.82 (s, 3H), 1.62-1.48 (m, 4H), 1.29-1.25 (m, 2H), 1.23-1.13 (m, 10H), 0.804 (t, 3H, J=7.6 Hz), 0.795 (t, 3H, J=7.2 Hz)
[0384] 13 C δ ppm (100 Hz, CDCl 3 ) 168.05 (CO), 150.62 (ArC), 150.00 (ArC), 137.99 (ArC), 124.59 (ArC), 123.31 (ArC), 121.83 (ArC), 120.80 (ArC), 112.47 (ArC), 111.60 (ArC), 67.98 (OCH 2 ), 67.03 (OCH 2 ), 64.42 (NCH), 56.49 (OCH 3 ), 56.15 (OCH 3 ), 36.72 (NCH 3 ), 31.99 (CH 2 ), 30.42 (CH 2 ), 29.71 (CH 2 ), 29.53 (CH 2 ), 29.43 (CH 2 ), 26.07 (CH 2 ), 22.82 (CH 2 ), 19.03 (CH 2 ), 14.29 (CH 3 ), 13.73 (CH 3 )
[0385] MS m/z, 333.10 [M-OctOSO 3 − ] +
[0000] Synthesis of 2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) butyl acetate, NTf 2 Salt (KG 2005):
[0000]
Synthesis:
[0386] A flask was charged with 2-(3,4-dimethoxyphenyl)-2-(3-methylimidazolium) butyl acetate, chloride salt (0.235 g, 064 mmol) and distilled water (8 mL). LiNTf 2 (0.201 g, 0.70 mmol) was added in one portion and the suspension was stirred vigorously for overnight at RT. The IL was washed with distilled water (2×3 mL). The solvent was then removed on the rotary evaporator and under high vacuum to give colorless oil at RT in 69.3% yield (0.272 g, 0.44 mmol).
Product Characterization:
[0387] Molecular formula: C 20 H 25 F 6 N 3 O 8 S 2
[0388] Molecular weight: 613.6 g/mol
[0389] 1 H NMR (400 Hz, CDCl 3 ) δ ppm 8.93 (s, 1H), 7.24 (s, 1H), 7.17 (s, 1H), 6.99 (d, 1H, J=2.0 Hz), 6.96 (dd, 1H, J=8.4, 2.0 Hz), 6.92 (d, 1H, J=8.0 Hz), 6.35 (s, 1H), 4.28-4.24 (m, 2H), 3.99 (s, 3H), 3.91 (s, 3H), 3.88 (s, 3H), 1.66-1.58 (m, 2H), 1.29 (tq, 2H, J=7.5, 7.5 Hz), 0.88 (t, 3H, J=7.4 Hz)
[0390] 13 C δ ppm (100 Hz, CDCl 3 ) 167.68 (CO), 151.01 (ArC), 150.19 (ArC), 136.54 (ArC), 123.47 (ArC), 122.44 (ArC), 121.20 (ArC), 120.02 (q, 2CF 3 , J=319 Hz), 118.42 (ArC), 111.98 (ArC), 111.94 (ArC), 67.35 (OCH 2 ), 64.98 (NCH), 56.28 (OCH 3 ), 56.23 (OCH 3 ), 36.78 (NCH 3 ), 30.39 (CH 2 ), 19.02 (CH 2 ), 13.70 (CH 3 ).
[0391] MS m/z, 333.10 [M-NTf 2 − ] +
[0000] Preparation of 1-(1-methoxycarbonyl)-1-(3,4-methylendioxyphenyl)methoxycarbonyl methyl)-pyridinium bromide (KG 2016):
[0000]
Synthesis:
[0392] To a stirred solution of (3,4-methylendioxyphenyl)methyl mandelate bromoacetate (1.502 g, 4.54 mmol) in diethyl ether (10 mL) at −15° C. under a nitrogen atmosphere, pyridine (0.37 mL, 4.54 mmol) was added drop wise. The reaction mixture was stirred at room temperature over the weekend. White precipitate appeared, but starting material was still present, so reaction mixture was refluxed for 4 h and stirred at RT overnight.
[0393] Product was washed with diethyl ether; the solvent was then removed on the rotary evaporator and under high vacuum to give a pure product as a white powder in 90.4% yield (1.682 g, 4.10 mmol).
Product Characterization:
[0394] Molecular formula: C 17 H 16 BrNO 6
[0395] Molecular weight: 410.2 g/mol
[0396] 1 H NMR (400 Hz, CDCl 3 ) δ ppm 9.41-9.40 (m, 2H), 8.53-8.49 (m, 1H), 8.10-8.06 (m, 2H), 6.91 (dd, 1H, J=8.0, 1.8 Hz), 6.86 (d, 1H, J=1.8 Hz), 6.82 (d, 1H, J=8.0 Hz), 6.68 (d, 1H, J=17.4 Hz), 6.09 (d, 1H, J=17.4 Hz), 6.01 (d, 1H, J=1.4 Hz), 6.00 (d, 1H, J=1.4 Hz), 5.92 (s, 1H), 3.89 (s, 3H)
[0000] Preparation of 2-(3,4-dimethoxyphenyl)-2-(pyridinium) methyl acetate, Chloride Salt (KG 2013):
[0000]
Synthesis:
[0397] To a stirred solution of methyl-2-chloro-2-(3,4-dimethoxyphenyl)acetate (0.895 g, 3.66 mmol) in diethyl ether (10 mL) at −15° C. under a nitrogen atmosphere, pyridine (0.35 mL, 4.37 mmol) was added drop wise. The reaction mixture was stirred at room temperature overnight, then was refluxed for 8 h and further pyridine was added (0.35 mL, 4.37 mmol). Yellow precipitate was collected and organic layer was evaporated and heated neat at 50° C. with pyridine (0.21 mL, 2.60 mmol). Product was washed with diethyl ether; the solvent was then removed on the rotary evaporator and under high vacuum to give a yellow powder in 88.9% yield (1.054 g, 3.26 mmol).
Product Characterization:
[0398] Molecular formula: C 16 H 13 ClNO 4
[0399] Molecular weight: 323.8 g/mol
[0400] 1 H NMR (600 Hz, CDCl 3 ) δ ppm 9.44-9.43 (m, 2H), 8.51-8.48 (m, 1H), 8.07 (s, 1H), 8.06-8.03 (m, 2H) 7.43 (d, 1H, J=2.0 Hz), 7.04 (dd, 1H, J=8.4, 2.1 Hz), 6.82 (d, 1H, J=8.4 Hz), 3.762 (s, 3H), 3.760 (s, 3H), 3.72 (s, 3H)
[0401] 13 C δ ppm(150 Hz, CDCl 3 ) 167.95 (CO), 150.98 (ArC), 149.99 (ArC), 146.57 (ArC), 144.99 (ArC), 128.02 (ArC), 123.35 (ArC), 121.80 (ArC), 113.43 (ArC), 111.59 (ArC), 73.44 (NCH), 56.48 (OCH 3 ), 56.00 (OCH 3 ), 54.01 (OCH 3 ).
[0402] MS m/z, 288.10 [M-Cl − ] +
[0403] mp: 118-119° C.
[0000] Preparation of 2-(3,4-dimethoxyphenyl)-2-(pyridinium) methyl acetate, Octylsulphate Salt (KG2014):
[0000]
Synthesis:
[0404] To a stirred solution of 2-(3,4-dimethoxyphenyl)-2-(pyridinium) methyl acetate, chloride salt (0.278 g, 0.86 mmol), in distilled water (8 mL) was added in one portion sodium octyl sulphate (0.207 g, 0.89 mmol). The mixture was left stirring overnight, then the water was evaporated on the rotary evaporator. The remaining product was dissolved in DCM and washed with water. The product was then dried on the rotary evaporator and under high vacuum to give colorless oil at RT in 41.6% (0.178 g, 0.36 mmol)
Product Characterization:
[0405] Molecular formula: C 24 H 35 NO 8 S
[0406] Molecular weight: 497.6 g/mol
[0407] 1 H NMR (600 Hz, CDCl 3 ) δ ppm 9.08-9.07 (m, 2H), 8.48-8.45 (m, 1H), 8.02-8.00 (m, 2H), 7.26 (s, 1H), 7.24 (d, 1H, J=1.9 Hz), 7.02 (dd, 1H, J=8.4, 2.0 Hz), 6.85 (d, 1H, J=8.4 Hz), 3.92 (t, 2H, J=6.9 Hz), 3.779 (s, 3H), 3.775 (s, 3H), 3.74 (s, 3H), 1.51 (tt, 2H, J=7.2, 7.2 Hz), 1.23-1.18 (m, 2H), 1.16-1.11 (m, 8H), 0.75 (t, 3H, J=7.1 Hz)
[0408] 13 C δ ppm (150 Hz, CDCl 3 ) 167.82 (CO), 151.20 (ArC), 150.28 (ArC), 146.96 (ArC), 145.02 (ArC), 128.36 (ArC), 123.18 (ArC), 122.09 (ArC), 113.52 (ArC), 111.87 (ArC), 74.51 (NCH), 67.76 (CH 2 ), 56.52 (OCH 3 ), 56.10 (OCH 3 ), 54.08 (OCH 3 ), 31.82 (CH 2 ), 29.61 (CH 2 ), 29.36 (CH 2 ), 29.25 (CH 2 ), 25.95 (CH 2 ), 22.65 (CH 2 ), 14.11 (CH 3 ).
[0409] MS m/z, 288.10 [M-OctOSO 3 − ] +
[0000] One Pot Method for Preparation of 2-(3,4-dihydroxyphenyl)-2-(3-methylimidazolium) butyl acetate Bromide Salt (KG 1041).
[0000]
Synthesis:
[0410] A solution of butyl 3,4-dihydroxy mandelate (10.04 g, 41.78 mmol), 1-methylimidazole (6.63 mL, 6.83 g, 83.25 mmol) in DCM (200 mL) was stirred at 0° C. Thionyl bromide (3.22 mL, 8.65 g, 41.62 mmol) was added drop wise to the solution. Reaction mixture was allowed to warm to RT and stirred for 24 h. Completion of reaction was confirmed by TLC. The volatiles were removed via rotary evaporation and the crude product was purified by column chromatography. (SiO 2 , 20% Methanol: 80% DCM) to yield a brown oil in 62% yield (9.97 g, 25.88 mmol).
Product Characterization:
[0411] Molecular formula: C 16 H 21 BrN 2 O 4 .
[0412] Molecular weight: 385.25 g/mol
[0413] 1 H NMR (400 Hz, d 6 -DMSO) δ ppm: 9.49 (s, 1H), 9.31 (s, 1H), 9.11 (s, 1H), 7.77 (t, 1H, J=2.0 Hz), 7.74 (t, 1H J=2.0 Hz), 6.85 (d, 1H, J=2.4 Hz), 6.83 (d, 1H, J=8.4 Hz), 6.75 (dd, 1H, J=2.4, 8.4 Hz), 6.60 (s, 1H), 4.26-4.14 (m, 2H), 3.86 (s, 3H), 1.59-1.51 (m, 2H), 1.23 (tq, 2H, J=7.2, 7.6 Hz), 0.83 (t, 3H, J=7.6 Hz)
[0414] 13 C δ ppm (100 Hz, d 6 -DMSO): 167.89 (C═O), 147.01 (ArC), 145.95 (ArC), 136.61 (ArC), 123.42 (ArC), 122.86 (ArC), 122.31 (ArC), 119.64 (ArC), 116.31 (ArC), 116.03 (ArC), 65.89 (CH), 63.52 (NCH 3 ), 35.95 (CH 2 ), 29.77 (CH 2 ), 18.33 (CH 2 ), 13.30 (CH 3 )
[0415] MS m/z, 305.15 [M-Br − ] +
[0000] Preparation of 2-(3,4-dihydroxyphenyl)-2-(3-methylimidazolium) butyl acetate, Octylsulphate Salt (KG 1042):
[0000]
Synthesis:
[0416] To a stirred solution of 2-(3,4-dihydroxyphenyl)-2-(3-methylimidazolium) butyl acetate bromide salt (2.0 g, 5.19 mmol), in distilled water (10 mL) was added in one portion sodium octyl sulphate (1.21 g, 5.19 mmol). The mixture was left stirring overnight, then the water was evaporated on the rotary evaporator. The crude product was dissolved in DCM and washed with water. The product was then dried on the rotary evaporator and under high vacuum to give brown oil in 41% yield (1.10 g, 2.13 mmol)
Product Characterization:
[0417] Molecular formula: C 24 H 38 N 2 O 7 S
[0418] Molecular weight: 514.63 g/mol
[0419] 1 H NMR (400 Hz, d 6 -DMSO) δ ppm: 9.49 (s, 1H), 9.31 (s, 1H), 9.07 (s, 1H), 7.74 (t, 1H, J=2 Hz), 7.72 (d, 1H, J=2 Hz), 6.83 (d, 1H, J=2.0 Hz), 6.82 (d, 1H, J=8.0 Hz), 6.74 (dd, 1H, J=2.0, 8.0 Hz), 6.53 (s, 1H), 4.26-4.14 (m, 2H), 3.86 (s, 3H), 3.68 (t, 2H, J=6.8 Hz), 1.58-1.45 (m, 4H), 1.28-1.19 (m, 12H), 0.86 (t, 3H, J=7.2 Hz), 0.84 (t, 3H, J=7.6 Hz).
[0420] 13 C δ ppm (100 Hz, d 6 -DMSO: 167.84 (C═O), 146.98 (ArC), 145.93 (ArC), 136.58 (ArC), 123.47 (ArC), 122.77 (ArC), 122.37 (ArC), 119.77 (ArC), 116.11 (ArC), 115.77 (ArC), 65.91 (CH), 65.45 (CH 2 ), 63.61 (NCH 3 ), 35.95 (CH 2 ), 31.22 (CH 2 ), 29.78 (CH 2 ), 29.03 (CH 2 ), 28.70 (CH 2 ), 28.65 (CH 2 ), 25.50 (CH 2 ), 22.06 (CH 2 ), 18.34 (CH 2 ), 13.93 (CH 3 ), 13.37 (CH 3 ).
[0421] MS m/z, 305.15 [M-OctOSO 3 − ] +
[0000] Heterogeneous & Homogenous Hydrogenation Reactions Using the Chiral ILs Vs. Conventional Solvents
[0422] The novel CILs were tested as solvents in both heterogeneous and homogeneous hydrogenation reactions. Four prochiral substrates were examined: dimethyl itaconate, tiglic acid, α-acetamido cinnamic acid and α-methyl-trans-cinnamaldehyde. Heterogeneous catalysis was investigated using the achiral catalyst, palladium on carbon, while homogeneous catalysis was attempted using Wilkinson's catalyst.
Hydrogenation Reaction Conditions at 1 atm of Hydrogen Gas
[0423] Heterogeneous hydrogenation of the panel of olefin substrates was investigated under 1 atmosphere of hydrogen gas in each of the chiral lactate based and chiral mandelate based ionic liquid solvents tested. Both Pd—C and PtO 2 hydrogenation catalysts were used and the results were compared with conventional solvents such as methanol, THF and DCM.
[0424] The prochiral olefins to be hydrogenated using the IL as solvent were chosen from the panel of literature test-substrates: dimethyl itaconate, 5 tiglic acid, 6 (Z)-α-(N-acetamido)cinnamic acid 7 (and subsequently its methyl ester) and α-methyl-trans-cinnamaldehyde 8.
[0000]
Hydrogenation Reactions of Dimethyl Itaconate 5
[0425] The catalytic hydrogenation of dimethyl itaconate 5 in the novel CILs led to one product, namely dimethyl 2-methylsuccinate 9. No stereoinduction was observed and the product 9 was formed as as a racemic mixture.
[0000]
[0000] 10% Palladium on carbon and Wilkinson's catalyst were separately investigated as catalysts for the hydrogenation of this prochiral substrate 5 in both achiral and chiral ILs.
General Procedure
Hydrogenation Reaction of Dimethyl Itaconate 5 in [NTf 2 ] IL
Catalyst: 10% Pd—C/Tris(triphenylphosphine)rhodium(I) Chloride/Taniaphos
[0426] The catalyst [(10% Pd/C, 5.0 mg, 0.12 mol %), (Tris(triphenylphosphine)rhodium(I) chloride, 0.05 g, 1.35 mol %) (bis(norbornadiene)rhodium(I) BF 4 , Taniaphos, 0.003 mmol, 0.75 mol %)] was weighed into a dry 2-neck round bottom flask. The predried CIL (2.0 mL) was then added to the flask, followed by dimethyl itaconate 5 (0.63 g, 4.00 mmol) and 3 N 2 /vacuum cycles were performed. The reaction mixture was stirred for 10 minutes or until reaching 55° C. Hydrogen was then introduced to the reaction via a balloon, and the progress of the reaction was monitored by 1 H NMR. Upon termination of the reaction, the products were extracted using hexane (10×3 mL). The mass recovery after extraction from the CIL was 100% (0.63 g). Dimethyl 2-methylsuccinate 9 was obtained in 98% yield (0.63 g, 3.94 mmol) as a racemic mixture using either Pd—C (KG 813) or Wilkinson's catalyst (KG 834) and in 68% conversion using the Taniaphos catalyst (KG 813).
Recycle Procedure
[0427] Following extraction of the products from the IL, the IL (containing the catalyst) was dried via rotary evaporation and analysed by 1H NMR. Following confirmation that the IL was substrate/product-free and had not degraded, fresh substrate was then added to the system and the reactions repeated as described.
[0000] NMR: dimethyl 2-methylsuccinate 9 Product
[0428] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 3.63 (s, 3H), 3.61 (s, 3H), 2.88-2.83 (m, 1H), 2.70 (dd, J=8.2, 8.2 Hz, 1H), 2.37 (dd, J=6.0, 6.0 Hz, 1H), 1.16 (d, J=7.2 Hz, 3H) 13 C NMR (100 MHz, CDCl 3 ) δ ppm 175.98, 172.27, 51.89, 51.68, 37.15, 35.64, 16.96. Data consistent with literature values for 9 10% Palladium on carbon, Wilkinson's catalyst and Adams' catalyst were used to investigate the hydrogenation of this substrate in the novel CILs.
Catalyst: 10% Palladium on Carbon
[0429] Experiments were carried out at 55° C. using 0.22 mol % catalyst.
[0000]
TABLE A
Lactate CILs Investigated in Hydrogenation of dimethyl itaconate 5
Chirality of
Conversion (%)
R
solvent
to 9
+/−
100
−
100
+/−
80
+/−
100
−
100
+/−
50
[0000]
TABLE B
Mandelate CILs Investigated in Hydrogenation of dimethyl itaconate 5
Chirality
Conversion (%)
R
of solvent
to 9
+/−
100
+/−
25
Catalyst: Wilkinson's Catalyst
[0430] The amount of catalyst deemed to be sufficient in order to induce relatively good percentage conversion was 1.26 mol % (50.0 mg).
[0000]
TABLE C
Lactate and Mandelate ILs investigated in Hydrogenation of dimethyl itaconate 5
Catalyst amount
Chirality
Wilkinson's
Conversion (%)
R
of solvent
catalyst
to 9
−
0.01 g
15
+
0.01 g
21
+
0.05 g
100
Hydrogenation of Dimethyl Itaconate 5 in Conventional Organic Solvents
[0431] Using 0.05 g of Wilkinson's catalyst in common organic solvents yielded poor percentage conversions.
[0000]
TABLE D
Conversion of 5 to 9 in Common Organic Solvents
Solvent
Conversion (%) to 9
Dichloromethane
7
Toluene
7
Methanol
11
Catalyst Recycling Effect
[0432]
[0000]
TABLE E
Recycled Catalyst Activity
[KG821]
Run
Conversion (%)
1
36
2
56
3
71
4
75
5
76
6
85
7
73
8
73
9
69
10
64
[0433] It is possible that an activation period for the catalyst in the IL was necessary in this case to achieve high conversion which might explain why maximum conversion was only reached after 6 runs.
CIL as Additive to Achiral IL in Hydrogenation of Dimethyl Itaconate 5
[0434] The effect of CILs as additives was investigated. S(+) 3-methyl-1-(1-phenyl-1-pentoxycarbonyl)methyloxycarbonylmethylimidazolium bis(trifluoromethane)sulfonimide [KG 817] was investigated as an additive with 3-methyl-1-pentyloxycarbonylmethylimidazolium bis(trifluoromethane)sulfonimide achiral IL.
[0000]
TABLE F
Conversion of 5 to 9 using CIL/IL Mixtures
KG 817
KG 48
IL amount
CIL amount
Conversion (%)
2 mL
—
74
—
2 mL
100
1.8 mL
0.2 mL
74
1.5 mL
0.5 mL
100
Hydrogenation Reactions of Acid 6
General Procedure
Hydrogenation Reaction of Tiglic Acid 6 in [NTf 2 ] IL [KG 831]
[0435] Reduction of tiglic acid led to the formation of chiral 2-methylbutanoic acid 10.
[0000]
Catalyst: 10% Pd—C or Tris(triphenylphosphine)rhodium(I) Chloride (Wilkinson's Catalyst) or PtO 2 (Adams' Catalyst)
[0436] The catalyst [(10% Pd/C, 5.0 mg, 0.12 mol %), (Tris(triphenylphosphine)rhodium(I) chloride, 0.05 g, 1.35 mol %), (PtO 2 , 5.0 mg, 0.55 mol %)] was weighed into a dry 2-neck round bottom flask. The pre-dried IL [KG 831] (2.0 mL) was then added to the flask, followed by tiglic acid 6 (0.40 g, 4.00 mmol) and 3 N 2 /vacuum cycles were performed.
[0437] The reaction mixture was stirred for 10 minutes or until reaching 55° C. (85° C. in the case of the Pd—C catalyst). Hydrogen was then introduced to the reaction via a balloon, and the progress of the reaction was monitored by 1 H NMR. Upon termination of the reaction, the products were extracted using hexane (10×3 mL). The mass recovery after extraction from the IL was 100% (0.40 g). 2-Methylbutanoic acid was obtained in 81% yield (Pd—C), 22% conversion (Wilkinson's catalyst), or 98% yield (Adams' catalyst) (0.40 g, 3.92 mmol).
[0000] NMR: 2-methylbutanoic acid 10 Product
[0438] 1 H NMR (400 MHz, CDCl 3 ) δ ppm 11.58 (br s, 1H), 2.35 (q, J=7.2 Hz, 1H), 1.68-1.61 (m, 1H), 1.46-1.40 (m, 1H), 1.11 (d, J=7.2 Hz, 3H), 0.89 (t, J=7.4 Hz, 3H) 13 C NMR (100 MHz, CDCl 3 ) δ ppm 183.71, 40.74, 26.51, 16.32, 11.51. Data consistent with literature values (M. Kawashima).
[0439] 10% Palladium on carbon, Wilkinson's catalyst and Adams' catalyst were used to investigate the hydrogenation of this substrate 6 to product 10 in the novel CILs.
Catalyst: 10% Pd/C
[0440]
[0000]
TABLE G
Lactate CILs in Hydrogenation of Tiglic acid 6 to 2-methylbutanoic acid 10
Amount of catalyst
Conversion (%)
R
Chirality
10% Pd/C
Temperature
to 10
+/−
0.05 g 0.05 g 0.15
55 85 85
0 81 93
Catalyst: Wilkinson's Catalyst
[0441]
[0000]
TABLE H
Convention Solvents vs. Lactate CILs in Hydrogenation of Tiglic acid 6 to
2-methylbutanoic acid 10
Solvent
Chirality
Conversion (%) to 10
Methanol
−
26
Ethyl acetate
−
8
−
22
Catalyst: Adams' Catalyst
[0442]
[0000] TABLE I Mandelate CILs in Hydrogenation of Tiglic acid 6 to 12-methylbutanoic acid 10 Conversion (%) R Chirality to 10 + 100 + 100
Hydrogenation Reactions of α-methyl-trans-cinnamaldehyde 8
[0443] The hydrogenation of this substrate led to a mixture of products.
[0000]
Catalyst: 10% Pd/C
[0444]
[0000]
TABLE J
Hydrogenation Reactions of α-methyl-trans-cinnamaldehyde 8 in Achiral ILs:
(Selectivity refers to 2-methyl-3-phenylpropanal, 12)
R
Temperature
Selectivity (%) for 12
Conversion (%)
Toluene
RT
67
56
55
78
12
80
100
11
55
0
0
55
0
0
[0445] Adams' Catalyst
[0000] TABLE K Hydrogenation Reactions of α-methyl-trans-cinnamaldehyde 8 in CILs vs. Achiral IL: (Selectivity refers to 2-methyl-3-phenylpropanal, 12) R Chirality Selectivity (%) for 12 Conversion (%) for 12 55 77 +/− 100 32 − 100 22 + 0 0 − 100 22 +/− 100 34 − 100 4
Hydrogenation Reactions of α-acetamido Cinnamic Acid 7 to 2-acetamido-3-phenylpropanoic Acid 11
[0446] The hydrogenation of α-acetamido cinnamic acid 7 led to a single product 2-acetamido-3-phenylpropanoic acid 11.
[0000]
Catalyst: 10% Pd/C
[0447] After 48 hours using 10% Pd/C (0.22 mol %) catalyst, 100% conversion of substrate 7 to product 11 was obtained using all but one CIL tested thus far.
[0000]
TABLE L
Hydrogenation Reactions of α-acetamide cinnamic acid 7 in CILs vs. Achiral IL vs Conventional
Solvent:
Conversion (%)
Solvent
Chirality
to 11
Ethyl acetate
−
100
−
100
+/−
100
+
0
Discussion of Hydrogenation Results (at 1 atm H 2 Gas Pressure)
[0448] Ditriflimide (NTf 2 ), (low viscosity and high hydrophobicity) and also octylsulfate (OctOSO 3 ) (high biodegradability, low hydrophobicity) anions have been tested for catalytic stereo inducing ability in a hydrogenation reaction with each class of chiral lactate and mandelate ILs (1, 2 racemic and also enantiomerically pure forms) from the original library in FIG. 1 . While the CILs tested did not give notable stereoinduction in all cases, substrate conversion and product selectivity where high in many cases using various prochiral substrates.
[0449] In the case of the lactate ILs 1, maximum conversion of substrate 5 to the reduced product 9 (100%) was achieved using either a propyl [KG 802, KG 808] or a pentyl [KG 804, KG 810] ester side chain and an NTf 2 counter anion at 55° C. in the presence of 22 mol % Pd—C catalyst.
[0450] With the mandelate chiral ILs, to achieve the same maximum conversion of 100% from substrate 5 to the reduced product 9, an ethyl ester side chain was used in conjunction with an NTf 2 counter anion. [KG 813]
[0451] Alternatively, under homogeneous conditions, Wilkinson's catalyst (chlorotris(triphenylphosphine)rhodium(I)—RhCl(PPh 3 ) 3 ) in conjunction with a mandelic acid based chiral IL containing a pentyl ester side chain and NTf 2 anion [KG 825] gave 9 in 100% conversion from substrate 5, with just 1.26 mol % catalyst.
[0452] Alternatively, under homogeneous conditions, Wilkinson's catalyst (chlorotris(triphenylphosphine)rhodium(I)—RhCl(PPh 3 ) 3 ) in conjunction with a mandelic acid based chiral IL containing a pentyl ester side chain and NTf 2 anion gave 9 in 100% conversion from substrate 5, with just 1.26 mol % catalyst.
[0453] Surprisingly, this conversion significantly surpassed that achieved in conventional solvents such as methanol (11%), DCM (7%) and toluene (7%). When the chiral IL was admixed with an economical achiral IL in a ratio of 3:1 (achiral/chiral) it was still possible to achieve 100% conversion to 9.
[0454] For the sterically hindered double bond of tiglic acid 6, a slightly lower conversion of 93% was achieved using Pd—C at 55° C., combining an ethyl ester side-chain with NTf 2 anion [lactate ILs] [KG 801]However, a PtO 2 catalyst increased the conversion of tiglic acid 6 into product 10 to 100% with either an ethyl [KG 821], or butyl ester side-chain [KG 823]. The excellent conversion was unexpected, since with this hindered substrate, Wilkinson's catalyst proved relatively ineffective at atmospheric hydrogen pressure (22% conversion/lactate IL, ethyl ester/NTf 2 [KG 807]).
[0455] With substrate α-methyl-trans-cinnamaldehyde 8 the reaction becomes more interesting because two possible products can be formed during the hydrogenation reaction, either that of carbon-carbon double bond reduction to provide product 12, or that of further reduction of the carbonyl group of substrate 8 to provide product 13.
[0000]
[0456] In practice, using Pd—C and hydrogen, it was possible to form only product 12 (as a racemic mixture) by a 100% selective reduction at 80° C. with 3-methyl-1-pentyloxycarbonylmethylimidazolium octylsulfate, an achiral ionic liquid [KG 35]. Nevertheless, while this selectivity exceeds that in the conventional solvent, toluene (67% selectivity for product 12), the conversion (11%) is lower than that seen in toluene (56% in toluene). However, using PtO 2 as catalyst it was possible to maintain 100% selectivity for product 12, yet increase the conversion to 34% with a mandelate-based IL as the pentyl ester, with an NTf 2 counter ion [KG 817].
[0457] (Z)-α-(N-acetamido)cinnamic acid 3 proved to be a relatively straightforward substrate, at least as far as conversion is concerned, with lactate (butyl side-chain) [KG 804] or the achiral ionic liquid with a pentyl ester chain, [KG 48] (both NTf 2 salts matching the 100% conversion achieved at atmospheric hydrogen pressure in ethyl acetate after 48 hours, using Pd—C as a heterogeneous catalyst.
Stereoselectivity and Aromatic Ring Reduction
[0458]
[0459] In a further experiment, the methyl ester substrate of substrate 7, (methyl α-acetamidocinnamate 14) was successfully reduced to product 15 using the asymmetric homogeneous catalyst, derived from the ligand (S)-1-diphenylphosphino-2-[(R)-α-(dimethylamino)-2-(diphenylphosphino)benzyl] ferrocene (Taniaphos SL-T001-1) combined with bis(norbornadiene) rhodium(I) tetrafluoroborate. Chiral GC was used to determine the enantiomeric excess of product formed.
[0000]
[0460] Generally pressures of 3 Atm or more may be required for this reaction. In this case though, (Taniaphos) reduction at 1 atm (the Taniaphos system has previously been demonstrated to be highly enantioselective at 1 atm in methanol, (Spindler et al.), it is a significant result because the products were produced enantiomerically enriched in the low toxicity and high biodegradability ionic liquid.
[0461] The enantiomeric excesses achieved when using the Taniaphos chiral catalyst system together with the panel of prochiral substrates were modest (at best 40% ee, in the reduction of dimethyl itaconate, 9, determined by chiral HPLC using a Daicel CHIRALPAK® IB column).
[0000] Chromatography Columns and Conditions used for Product Analysis
[0000]
Column: Chiral-L-Val
170° C. isoratic
2.0 ml/min
Inj/Det Temp. 270/300° C.
Split ratio 200:1
Ret. times 284, 300 minutes
Column: CP-Cyclotextrin-β-2,3,6-M-19
110° C. (12 min. bold) 10° C./min. 145° C. (10 min. bold)
1.1 ml/min
Inj/Det Temp. 250/260° C.
Split ratio 200:1
Ret. times 16.34, 16.47 minutes
Column: CP-Cyclodextrin-β-2,3,6-M-19
45° C. Isocratic
1.1 ml/min
Inj/Det Temp. 250/260° C.
Split ratio 200:1
Ret. times 5.35, 5.48
minutes
Asymmetric Hydrogenation Catalyst, [(R,R)-DiPAMP-Rh(COD)][BF 4 ]
[0462] Both Taniaphos and DiPAMP-based chiral catalysts give high enantiomeric excesses (76-93%) in the reduction of α-acetamido cinnamic acid methyl ester 14 ( FIGS. 4 , 5 and Table M).
[0463] GC analysis indicates the formation of a smaller co-product resulting from the surprising reduction of an aromatic system (in α-acetamido cinnamate methyl ester) under 1 atmosphere of hydrogen using the Taniaphos catalyst system ( FIG. 5 ). This only occurs using either (S) or (R) 3-methyl-1-(methylmandelatecarbonylmethyl)imidazolium bis(trifluoromethane)sulfonlmide [KG 93/94] as a solvent. The hydrogenation of aromatic systems would normally be a very difficult transformation and has been reported to require the presence of Ru(0) nanoparticles of the catalyst to occur at atmospheric pressure (Prechtl). Only the combination of the Taniaphos system and the chiral IL gave the aromatic reduction product. This reaction, which requires one extra day's catalytic reduction, demonstrates a marked increase in reactivity when using a chiral ionic liquid, especially considering that it unusually occurs at only 1 atmosphere of hydrogen, potentially giving rise to industrial processes that are more energy-efficient, safer and greener.
[0464] Hydrogenation of methyl α-acetamidocinnamate 14 using Rh Taniaphos and Rh DiPAMP homogeneous chiral catalysts, gave conversions ranging from 0-100%, with an optimum ee of 75.6% at 87.8% conversion using Rh DiPAMP and (S)-3-methyl-1-(1-phenyl-1-methoxycarbonylmethyl)imidazolium bis(trifluoromethane)sulfonimide KG94 as solvent after 42 h reaction at 88° C. (Table M). The same reaction with Rh Taniaphos and either (S) or (R)-3-methyl-1-(1-phenyl-1-methoxycarbonylmethyl)imidazolium bis(trifluoromethane)sulfonlmide [KG 93/94] gave the opposite enantiomer in excess, together with a second product resulting from reduction of the aromatic ring (GC-MS analysis gives mass ions consistent with hydrogenation of the aromatic system to a substituted cyclohexane) when the reaction is run to high conversion. ( FIGS. 4 , 5 and Table M).
[0465] GC analysis indicated that along with the expected acetamide of D-phenylalanine methyl ester the reaction mixture contained two isomeric forms of the starting material (Retention Time=15.1 and 10.75 min) (Z and E-isomers) as well as two enantiomeric forms of the aromatic-reduced product, (Retention Time=8 and 9 min) in the same ratio as the desired product.
[0000] Discussion of Hydrogenation Reaction at Hydrogen Gas Pressure Above 1 Atmosphere (50 psi)
[0466] The CIL KG90 gave an increase in ee (93.2%) for the product compared to MeOH as the solvent (92.4%). This demonstrates that the chiral ionic liquid solvent can be tailored to a catalyst to give an improved enantioselectivity compared to MeOH. The other enteries in the table above show that the structure of the CIL is important for an increase in enantioselectivity. KG 56 and KG 806 show that opposite enantiomers can lead to different degrees of enantioinduction conferred by the catalyst. The achiral IL KG 56 gave the lowest level of enantioselectivity with the chiral catalyst in the table above. We submit that chiral ionic liquids contained within this patent can be useful solvents or additives for asymmetric induction.
[0000] TABLE M Enantioselective Hydrogenation of methyl alpha-acetamidocinnamate 14 using CILs vs ILs Substrate Catalyst Solvent Temp Time Conversion to 15 methyl α-acet- (S)-Ru(OAc) 2 (T-BINAP) Achiral IL: 83° C. 4 days No reaction amidocinnamate 4.2 mg 3-methyl-1-(pentoxycarbonylmethyl) 0.21 g 4.68 μmoles imidazolium NTf 2 (0.961 mmol) KG 48 −0.75 ml methyl α-acet- Rh Taniaphos SL-T001-1 Achiral IL: 86° C. 5 days 22% conversion amidocinnamate 2.0 mg Rh(nbd) 2 BF 4 3-methyl-1-(pentoxycarbonylmethyl) ee: 80.2% 0.163 g 4.3 mg SL-T001-1 imidazolium NTf 2 (D enantiomer major product) (0.75 mmol) 5.35 μmoles KG 48 0.75 ml methyl α-acet- Rh Taniaphos SL-T001-1 Chiral IL: 68° C. 42 hours 100% conversion amidocinnamate 2.2 mg Rh(nbd) 2 BF 4 (S)-3-methyl-1-(1-phenyl-1- ee: 75.6% 0.074 g 4.2 mg SL-T001-1 methoxycarbonylmethyl)imidazolium NTf 2 (D enantiomer major product) (0.34 mmol) 5.88 μmoles KG 94 0.21 g [also minor product of reduced aromatic ring] methyl α-acet- Rh Taniaphos SL-T001-1 Chiral IL: 95° C. 20 hours 100% conversion amidocinnamate 3.3 mg Rh(nbd) 2 BF 4 (R)-3-methyl-1-(1-phenyl-1- ee: 85.0% 0.100 g 5.4 mg SL-T001-1 methoxycarbonylmethyl)imidazolium NTf 2 (D enantiomer major product) (0.40 mmol) 8.82 μmoles KG 93 0.43 g [also minor product of reduced aromatic ring] methyl α-acet- [(R,R)-DiPAMP-Rh(cod)] BF 4 Chiral IL: 88° C. 42 hours 94% conversion amidocinnamate 14 mg (S)-3-methyl-1-(1-phenyl-1- ee: 87.8% 0.109 g 18.54 μmoles methoxycarbonylmethyl)imidazolium NTf 2 (L enantiomer major product) (0.50 mmol) KG 94 0.32 g methyl α-acet- [(R,R)-DiPAMP-Rh(cod)] BF 4 Chiral IL: 86° C. 20 hours 50% conversion amidocinnamate 4.3 mg (R)-3-methyl-1-(1-phenyl-1- ee: 80.8% 0.075 g 5.70 μmoles methoxycarbonylmethyl)imidazolium NTf 2 (L enantiomer major product) (0.34 mmol) KG 93 0.56 g T-BINAP: 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl: Rh Taniaphos: [(S)-1-Diphenylphosphino-2-[(α-(R)-N,N-dimethylamino)-(o-diphenylphosphinophenyl)-methyl]-ferrocene-(1,5-cyclooctadiene)-rhodium(I)]-tetrafluoroborate
Hydrogenation Reaction Conditions at Hydrogen Gas Pressure Above 1 Atmosphere (50 psi)
[0000]
Substrate
tonic Liquid
Temp/Pressure
Run Time
Conversion a
ee for 17 b,c
80° C./50 psi
Complete (<0.5 h)
>95%
93.2% (S)
80° C./50 psi
Complete (<0.5 h)
>95%
84.4% (S)
80° C./50 psi
Complete (<0.5 h)
>95%
82.0% (S)
80° C./50 psi
Cpmplete (<0.5 h)
>95%
89.2% (S)
MeOH
80° C./50 psi
Complete (<0.5 h)
>95%
92.4% (S)
Notes:
a Conversion determined to by 1 H NMR using integration of CH 3 of N—Ac group;
b ee at 210 nm determined using HPLC;
c major enantiomer assignment based on literature precedent
Conditions:
Catalyst: 0.5 mol % [((R,R)-DiPAMP)Rh(cod)]BF 4 :
Solvent: 2 mL (2 g for solid IL)
Temp.: 80° C.
Substrate: α-acetamidocinnamic acid methyl ester, 1 mmol
H 2 : 50 psi
Stirring: 400 rpm
Biodegradability & Toxicity
[0467] The biodegradability of the ILs can be evaluated applying the following standard methods: (i) Sturm Test (ii) Closed Bottle Test (OECD 301D) (iii) CO 2 Headspace Test (ISO 14593). Both tests (ii) and (iii) are included in the European Regulation (EC) No 648/2004 of biodegradability of detergent surfactants, the CO 2 Headspace Test being the reference method for laboratory testing of ultimate biodegradability. In the Closed Bottle and CO 2 Headspace tests, the compound to be evaluated is added to an aerobic aqueous medium inoculated with wastewater microorganisms and the depletion of dissolved O 2 or the CO 2 evolution is measured periodically and reported as a percentage of theoretical maximum. Sodium n-dodecyl sulfate (SDS) is generally used as a reference substance. An IL will be considered “readily biodegradable” and, therefore it will be assumed that such a chemical will be rapidly and completely biodegraded in an aquatic environment under aerobic conditions, if the biodegradation level measured according to one of the described tests is higher than 60% within 28 days.
[0468] IL toxicity tests are based on systems with different biological complexity levels. The toxicity of the ILs has been measured on a wide range of organisms from bacteria and fungi, to higher organisms such as zebrafish, the soil nematode and the freshwater snail. LC50, IC50, EC50 and MIC values are used as a measurement of the toxicity of the ILs on the organism. Growth inhibition studies have also been carried out on algae and terrestrial plants. Such tests indicate the levels at which the IL in a biological system prevents or disrupts growth. Data from such studies on ILs can then be compared to well known values for common organic solvents. In general the toxicity of ionic liquids tested to date is found to be some orders of magnitude higher than that of conventional solvents such as acetone and methanol. A common problem with the toxicity of ionic liquids is associated with the presence of an extended hydrocarbon chain. The length of the side chains was found to influence the dialkylimidazolium ionic liquid's toxicity, with longer chain length proving to be more toxic. In fact, Bodor et al. (9) have shown that the long chain ester derivatives of methyl imidazoleshow effective antimicrobial activity at ppm concentrations, clearly demonstrating the toxic effect of such ILs on microbes.
Biological Testing of Chiral Ionic Liquids:
[0469] All the 12 bromide salts and 12 octylsulfate CILs in the table below were screened against fungi and bacteria.
[0000] Mandelate derivatives IL no. R Configuration KG818 KG833 KG826 KG824 KG816 KG90 KG89 KG91 KG835 C 2 H 4 OC 2 H 5 C 5 H 11 C 2 H 4 OC 2 H 5 C 5 H 11 C 5 H 11 CH 3 CH 3 CH 3 C 2 H 4 OC 2 H 5 RS R S S RS R RS S R Lactate derivatives IL no. R Configuration KG160 KG159 KG161 C 2 H 4 OC 2 H 5 C 5 H 11 C 2 H 4 OC 2 H 5 RS R R Mandelate derivatives IL no. R Configuration KG400 KG303 KG305 KG302 KG304 KG87 KG86 KG88 KG301 C 2 H 4 OC 2 H 5 C 5 H 11 C 2 H 4 OC 2 H 5 C 5 H 11 C 5 H 11 CH 3 CH 3 CH 3 C 2 H 4 OC 2 H 5 RS R S S RS R RS S R Lactate derivatives IL no. R Configuration KG172 KG171 KG173 C 2 H 4 OC 2 H 5 C 5 H 11 C 2 H 4 OC 2 H 5 RS R R
CILs with bromide as anion have been screened against the following Fungi and bacteria:
[0000]
Fungi
1. CA1 Candida albicans ATCC 44859
2. CA2 Candida albicans ATCC 90028
3. CP Candida parapsilosis ATCC 22019
4. CK1 Candida krusei ATCC 6258
5. CK2 Candida krusei E28
6. CT Candida tropicalis 156
7. CG Candida glabrata 20/l
8. CL Candida lusitaniae 2446/l
9. TB Trichosporon beigelii 1188
10. AF Aspergillus fumigatus 231
11. AC Absidia corymbifera 272
12. TM Trichophyton mentagrophyte s 445
[0000]
Bacteria
1. SA Staphylococcus aureus CCM 4516/08
2. MRSA Staphylococcus aureus H 5996/08
Methiciline-resistant
3. SE Staphylococcus epidermidis H 6966/08
4. EF Enterococcus sp. J 14365/08
5 . EC Escherichia coli CCM4517
6. KP Klebsiella pneumoniae D 11750/08
7. KP-E Klebsiella pneumoniae J 14368/08
ESBL-positive
8. PA Pseudomonas aeruginosa CCM 1961
[0470] In vitro antifungal activities of the compounds were evaluated on the collection of fungal strains deposited at the Department of Biological and Medical Sciences, Faculty of Pharmacy, Charles University, Czech Republic. All the isolates were maintained on Sabouraud dextrose agar prior to being tested.
[0471] Minimum inhibitory concentrations (MICs) were determined by the microdilution format of the NCCLS M27-A guidelines. Dimethyl sulfoxide served as a diluent for all compounds; the final concentration did not exceed 2%. RPMI 1640 (Sevapharma, Prague) medium supplemented with L-glutamine and buffered with 0.165 M morpholinepropanesulfonic acid to pH 7.0 was used as the test medium. The wells of the microdilution tray contained 100 μl of the RPMI 1640 medium with 2-fold serial dilutions of the compounds (1000 to 0.24 μmol/l for the new compounds) and 100 μl of inoculum suspension. Fungal inoculum in RPMI 1640 was prepared to give a final concentration of 5×103±0.2 cfu.ml-1. The trays were incubated at 35° C. and MICs were read visually for filamentous fungi and photometrically for yeasts as an optical density (OD) at 540 nm after 24 h and 48 h. The MICs were defined as 80% inhibition of the growth of control. MICs were determined twice and in duplicate. The deviations from the usually obtained were no higher than the nearest concentration value up and down the dilution scale.
[0000] Results against Fungi Fungi Samples-MIC/IC 80 (μmol · l −1 ) (hr) KG89 KG90 KG91 KG816 KG833 KG824 KG835 KG826 KG818 KG160 KG159 KG161 CA1 24 h >1000 >1000 >1000 500 500 500 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 CA2 24 h >1000 >1000 >1000 1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 CP 24 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 CK1 24 h >1000 >1000 >1000 1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 CK2 24 h >1000 >1000 >1000 1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 CT 24 h >1000 >1000 >1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 CG 24 h >1000 >1000 >1000 1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 CL 24 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 TB 24 h >1000 >1000 >1000 1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 AF 24 h >1000 >1000 >1000 1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 AC 24 h >1000 >1000 >1000 1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 TM 72 h >1000 >1000 >1000 500 500 500 >1000 >1000 >1000 >1000 >1000 >1000 120 h >1000 >1000 >1000 500 500 500 >1000 >1000 >1000 >1000 >1000 >1000 Note: X (μl) + Y (medium, ml): Max concent. of sample mol.L−1/DMSO (%): X = Amount (mg) + DMSO (I)
The CILs bromides have also been screened against the following bacteria:
[0000] Results against Bacteria Bacteria Samples - MIC/IC 80 (μmol · l −1 ) (hrs) KG89 KG90 KG91 KG816 KG833 KG824 KG835 KG826 KG818 KG160 KG159 KG161 SA 24 h >1000 >1000 >1000 1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 MRSA 24 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 SE 24 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 EF 24 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 EC 24 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 KP 24 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 KP-E 24 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 PA 24 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 48 h >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000 >1000
The octylsulfate CILs have also been screen against all above fungi and bacteria. Results in Tables below:
[0000]
Results against Fungi
Fungi
Samples-MIC/IC 80 (μmol · l −1 )
(hr)
KG86
KG87
KG88
KG303
KG302
KG304
KG301
KG305
KG400
KG172
KG171
KG173
CA1
24 h
>1000
>1000
>1000
500
1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
CA2
24 h
>1000
>1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
CP
24 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
CK1
24 h
>1000
1000
>1000
1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
CK2
24 h
>1000
1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
CT
24 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
CG
24 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
CL
24 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
TB
24 h
>1000
>1000
>1000
1000
1000
500
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
AF
24 h
>1000
>1000
>1000
1000
1000
500
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
AC
24 h
>1000
>1000
>1000
1000
1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
TM
72 h
>1000
1000
>1000
250
250
250
>1000
>1000
>1000
>1000
>1000
>1000
120 h
>1000
>1000
>1000
500
500
500
>1000
>1000
>1000
>1000
>1000
>1000
[0000]
Results against Bacteria
Bacteria
Samples - MIC/IC 80 (μmol · l −1 )
(hrs)
KG86
KG87
KG88
KG303
KG302
KG304
KG301
KG305
KG400
KG172
KG171
KG173
SA
24 h
>1000
>1000
>1000
1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
MRSA
24 h
>1000
>1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
SE
24 h
>1000
>1000
>1000
500
1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
EF
24 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
EC
24 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
KP
24 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
KP-E
24 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
PA
24 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
48 h
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
>1000
Toxicity of Imidazolium CILs
[0472] For all these chiral ionic liquids, only the pentyl side chain mandelate CILs (KG302, KG303 and KG304) were found to inhibit the growth of fungi and bacteria. Introducing oxygen functionality in side chain did not lead to increased toxicity. All lactate CILs were found to be non-toxic.
Toxicity of Pyridinium CILs
[0473] KG 2013 and KG 2015 screened against 5 bacteria strains: Pseudomonas Putida (CP1), Pseudomonas Putida (KT2440), Escherichia Coli, Bacillus Subtilis , and Pseudomonas Fluorescens . KG 1043 screened against 4 strains Pseudomonas Putida (CP1), Pseudomonas Putida (KT2440), Escherichia Coli , and Pseudomonas Fluorescens . All 3 pyridinium ionic liquids have low antimicrobial toxicity (IC50>1 mM).
[0000]
IC50 values (μM)
Bacteria
KG 1043
KG 2013
KG 2015
E. Coli
>1000
>1000
>1000
B. Subtilis
nd a
>1000
>1000
P. Fluorescens
>1000
>1000
>1000
P. Putida (CP1)
>1000
>1000
>1000
P. Putida (KT2440)
>1000
>1000
>1000
a nd = not determined.
Biodegradable CIL
[0474] FIGS. 1 and 2 and Tables N and O demonstrate that all of the tested lactate and madelate based CILs compounds having OctOSO 3 − anions are biodegradable, since they satisfy the requirement that biodegradability is higher than 60% within 28 days using the CO 2 Headspace Test.
[0000]
TABLE N
% biodegradation lactate CILS
Days
Compound
0
6
14
21
28
SDS
0
81
88
90
92
KG 162
0
46
57
61
64
KG 163
0
49
60
63
67
KG 166
0
50
63
66
67
KG 167
0
51
62
69
69
KG 170
0
52
65
72
72
KG 171
0
54
67
70
71
KG 172
0
55
64
69
69
KG 173
0
59
69
74
74
[0000]
TABLE O
% biodegradation mandelate CILs
Days
Compound
0
6
14
21
28
SDS
0
84
87
90
88
KG 301
0
63
73
78
80
KG 302
0
66
76
81
79
KG 303
0
62
72
77
79
KG 304
0
64
78
79
82
KG 305
0
73
77
85
83
KG 306
0
66
75
83
82
KG 308
0
62
71
78
78
[0000]
TABLE P
Library of 118 Chiral salts prepared
Ionic Liquid
Br −
NTf 2 −
OctOSO 3 −
KG 150
KG 800
KG 162
KG 152
KG 801
KG 164
KG 154
KG 802
KG 166
KG 156
KG 803
KG 168
KG 158
KG 804
KG 170
KG 160
KG 805
KG 172
KG 151
KG 806
KG 163
KG 153
KG 807
KG 165
KG 155
KG 808
KG 167
KG 157
KG 809
KG 169
KG 159
KG 810
KG 171
KG 161
KG 811
KG 173
KG 2017
KG 2016
—
KG 89
KG 92
KG 86
KG 812
KG 813
KG 307
KG 814
KG 815
KG 308
KG 816
KG 817
KG 304
KG 818
KG 819
KG 400
KG 91
KG 94
KG 88
KG 820
KG 821
KG 300
KG 822
KG 823
KG 306
KG 824
KG 825
KG 302
KG 826
KG 827
KG 305
KG 90
KG 93
KG 87
KG 828
KG 829
KG 401
KG 830
KG 831
KG 832
KG 833
KG 834
KG 303
KG 835
KG 836
KG 301
KG 2011
(−)
(−)
KG 1022
KG 1029
KG 1026
KG 1027
KG 1037
KG 1038
KG 1034
(−)
(−)
KG 1036
KG 1039
KG 1044
KG 1035
KG 1040
KG 1047
KG 1020
(−)
(−)
KG 1041
(−)
KG 1042
Cation
Cl−
Ntf 2 −
OctOSO 3 −
KG 1025
—
KG 1042
KG-2000
KG-2002
KG-2001
KG-2003
KG-2005
KG-2004
KG-2006
KG-2008
KG-2007
KG 2012
—
—
Ionic Liquid
Br −
NTf 2 −
OctOSO 3 −
KG 1043
KG 1046
KG 1045
KG 2016
(−)
(−)
KG 2015
(−)
(−)
Ionic Liquid
Cl −
NTf 2 −
OctOSO 3 −
KG 2013
—
KG 2014
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Saibh Morrissey, Ian Beadham and Nicholas Gathergood, Green Chem., 2009, 11, 466-474
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|
A chiral ionic compound comprising an alkyl substituted imidazolium or pyridinium cationic core having an alkyl ester side chain (-alkyl-C(O)O—) directly linked to the core and an associated counter anion, characterized in that the —O— atom of the ester side chain is linked to an alpha, a beta or a gamma hydroxycarboxylic acid functionality via the alpha, beta or gamma hydroxy of the acid functionality and the hydroxycarboxylic acid functionality has at least one asymmetric carbon, or characterized in that an —N═ atom of the alkyl substituted imidazolium or pyridinium cationic core is substituted with an alpha, a beta or a gamma hydroxy group of a alpha, a beta or a gamma hydroxycarboxylic acid functionality and the hydroxycarboxylic acid functionality has at least one asymmetric carbon. The chiral ionic liquids (CILs) may be used as novel solvents, in particular for organic synthesis. The CILs have the potential to induce asymmetry into substrates or catalysts in a variety of organic transformations. A number of the compounds have low antimicrobial and low antifungal toxicities and are also biodegradable CILs.
| 2
|
BACKGROUND OF THE INVENTION
The present invention relates to a hinge for wings or doors.
The use of a hinge made in accordance with the present invention is particularly advantageous for constraining the door of an electrical appliance to the respective supporting frame.
In the following description and by way of example only, without limiting the scope of the invention, the present invention is described with reference to an oven.
In known types of ovens hinges usually comprise two separate elements, kinematically connected to one another and both having a box-shaped structure. More precisely, one of the two box-shaped structures is fixed to the oven supporting frame, at one side of the oven mouth, whilst the other is fixed to one edge of the door, which is that way is rendered movable with a tilting action relative to the above-mentioned frame.
Between the two box-shaped structures a lever, usually a rocker lever, is operatively inserted, pivoting on one of the two box-shaped structures, usually on the one fixed to the door, and having a first arm rigidly constrained to the other of the two box-shaped structures. The second arm of the lever, coplanar with the first, is operated on by elastic elements which influence the movement of the door, for both opening and closing. Said elastic elements are housed in the box-shaped structure to which the lever is hinged and, more precisely, operate between that box-shaped structure and a rod positioned inside it. The free end of the rod, that is to say the end not interacting with the elastic elements, pivots at the above-mentioned second arm of the lever.
During door rotation starting from the closed position, the elastic elements oppose, during a first step, the detachment of the door from the oven supporting frame and, in a second step, subsequent rotation of the door and its consequent lowering to an end of stroke position in which the oven mouth is completely open. In this second opening step, the door, under the combined action of its own weight which promotes its descent and of the elastic elements which apply a braking action, performs a gradual rotation.
During door rotation starting from its open end of stroke position, the action of the elastic elements is first balanced by the weight of the door, initially guaranteeing gradual closing rotation; however, then, in the absence of a braking action by the user, the elastic elements push the door towards the oven frame with such a force that it often closes in a rather sudden and noisy way.
SUMMARY OF THE INVENTION
The present invention has for an aim to provide a hinge for wings or doors which is free of the above-mentioned disadvantage.
Accordingly, the present invention provides a hinge for wings or doors comprising the features described in any of the claims herein.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is now described, by way of example and without limiting the scope of application, with reference to the accompanying drawings, in which:
FIGS. 1 a and 1 b are respectively a front view and longitudinal section of a hinge made in accordance with the present invention, in its closed position and associated with an oven, the latter only partly, schematically illustrated;
FIG. 2 is an exploded view of the hinge of FIG. 1 a;
FIGS. 3 a , 3 b and 3 c are respectively a front view, a longitudinal section and a perspective view with some parts cut away for clarity, of the hinge of FIG. 1 a in an intermediate position; and
FIGS. 4 a and 4 b are respectively a front view and a longitudinal section of the hinge of FIG. 1 a in its open position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIGS. 1 a and 1 b , the numeral 1 denotes as a whole an oven comprising a frame 2 to which a door 3 is connected by two hinges 4 , only one of which is illustrated.
Each of the two hinges 4 comprises a first element 5 , fixed to the oven 1 frame 2 at a respective side of the oven mouth, and a second element 6 , fixed to a respective edge of the door 3 . In particular, the shape of the first element 5 and the second element 6 is substantially box-shaped and extended and they are kinematically connected to one another by a connecting lever 7 which is also part of the hinge 4 . The lever 7 is a rocker lever, pivoting on the second element 6 by means of a pin 8 and has a first arm 9 a rigidly constrained to the first element 5 to render the door 3 movable with a tilting action relative to the frame 2 between a closed position and an open position.
The central longitudinal axes of the lever 7 and of the second element 6 , labeled A and B respectively, lie in a plane at a right angle to the central longitudinal axis of the pin 8 , labeled C, which is the axis of rotation of the door 3 relative to the frame 2 , and they are at a right angle to one another in the above-mentioned closed position ( FIGS. 1 a and 1 b ) and substantially aligned in the above-mentioned open position ( FIGS. 4 a and 4 b ).
As illustrated in FIG. 1 b , the second element 6 has a transversal separator 10 , in an intermediate position between the two longitudinal ends of the second element 6 , specifically between the end hinged to the lever 7 , labeled 11 , and an end opposite to the latter, labeled 12 .
Between the separator 10 and the end 12 there is a pre-compressed helical spring 13 , held in contact with the separator 10 by the head 14 of a rod 15 positioned coaxially inside the spring 13 .
The rod 15 exits the spring 13 longitudinally with one end 16 , which passes through an opening made in the separator 10 and points towards the above-mentioned end 11 . In this way, the opening made in the separator 10 acts as a guide for the rod 15 , constraining it to a longitudinal linear motion.
The end 16 of the rod 15 is hinged, by a pin 17 , to the first longitudinal end 18 of a fork 19 , whose second longitudinal end 20 is hinged to the lever 7 by a pin 21 positioned near the above-mentioned pin 8 . The pin 17 is slidably constrained to two guide and end of stroke slots 22 , made in the sides of the second element 6 and extending in a prevalent direction of extension parallel with the direction B.
The position of the pin 21 , which is closer to the axis B than the pin 8 , and the pre-compression of the spring 13 , guarantee an elastic action which tends to continuously push and hold the door 3 in its closed position.
Only when the closed position is almost reached, from and towards the closed position, overlapping with the above-mentioned elastic action of the spring 13 there is the action of another pre-compressed helical spring 23 , designed to operate in conjunction with a cam 24 made on a second arm 9 b of the rocker lever 7 , through a rod 25 acting on a cam follower 26 , to give the door 3 a spring-to closing movement and to define a door stable semi-open position. Specifically, the follower 26 is supported by a pin 27 slidably constrained to two guide and end of stroke slots 28 , made in the sides of the second element 6 and extending in a prevalent direction of extension parallel with the direction B. The follower 26 is pushed towards the cam 24 by a race made on one end of the rod 25 , and the latter is pushed by the spring 23 which is stopped in contact with a transversal separator 29 in the second element 6 . The separator 29 is in an intermediate position between the separator 10 and the end 11 of the second element 6 and has an opening which acts as a guide for the rod 25 , so as to constrain the rod to a longitudinal linear motion.
The spring 23 is smaller than the spring 13 , since, while the function of the spring 13 is mainly to balance the weight of the door 3 , the function of the spring 23 is, as indicated, to give the door 3 a spring-to closing movement and to define a door stable semi-open position.
The two springs 13 and 23 , the relative rods 15 and 25 , the fork 19 and the cam follower 26 as a whole form elastic means 30 , inserted between the second element 6 and the lever 7 to apply on the lever 7 a two-step elastic action, specifically, during a first step, when the closed position is almost reached, from and towards the closed position, in which the action of the two springs 13 and 23 overlaps, and in a second step, between the above-mentioned door 3 stable semi-open position and the fully open position, in which the elastic action on the lever 7 is only applied by the spring 13 .
Each of the two hinges 4 also comprises damping means 31 , contained in the second element 6 and designed to apply a damping action on the lever 7 at the end of the closing stroke, that is to say, during the reciprocal motion of the first element 5 and the second element 6 , when the door 3 closed position is almost reached.
The damping means 31 comprise a gas or fluid cylinder 32 , having an outer body 33 mounted in the second element 6 , near the longitudinal end 12 of the latter, and a rod 34 which can move with linear motion relative to the outer body 33 .
The outer body 33 is housed in a fixed position in a support 35 which is constrained to the above-mentioned end 12 by a cylindrical hinge 36 .
The rod 34 consists of a first portion 37 acting directly on the cylinder 32 piston and of a second portion 38 forming an extension, having a first longitudinal end 39 connected to the first portion 37 and a second longitudinal end 40 which is free, designed to act on the lever 7 during the reciprocal motion of the first element 5 and the second element 6 and when the closed position is almost reached.
For this purpose, the lever 7 has two thrust projections 41 , extending in such a way that they are aligned with one another longitudinally from two opposite faces of the lever 7 , and the end 40 has a fork-shaped free end portion, designed to make contact with the projections 41 , simultaneously, when the door 3 has almost reached its closed position, and to remain in contact until the closed position is reached. As illustrated in FIG. 2 , the projections 41 are formed by the two longitudinal ends of a cylindrical element 42 , inserted in a through-hole 43 in the lever 7 and rigidly constrained to the lever.
The following is a brief description of the operation of one of the two hinges 4 starting at the door 3 closed position, illustrated in FIGS. 1 a and 1 b.
The torque applied to the door 3 when it is opened by the user and, beyond a predetermined rotation, by the weight of the door 3 , conflicts with the torque generated by the elastic means 30 , which therefore render the movement of the door 3 towards the fully open position gradual and subject to a braking action. During the initial opening step, the action applied on the lever 7 by the damping means 31 , which continues for as long as there is contact between the end 40 and the projections 41 , is negligible compared with the torque applied by the user.
Starting from the door 3 fully open position, a rotation of the door towards the closed position is promoted by the action of the elastic means 30 and is initially hindered by the weight of the door 3 . When the door 3 reaches an intermediate closing position, in which contact is made between the end 40 and the projections 41 ( FIGS. 3 a , 3 b and 3 c ), following cylinder 32 compression, the damping means 31 apply a damping action conflicting with the closing action applied by the elastic means 30 , and therefore render the door 3 movement towards the fully closed position gradual and subject to a braking action.
It is therefore evident that, even in the absence of a braking action by the user, the door 3 , pushed towards the oven 1 frame 2 by the elastic means 30 , reaches the frame in a gentle, silent way thanks to the end of stroke damping provided by the damping means 31 .
It should also be emphasized that the damping means 31 are housed in the hinge 4 , in a position hidden from view and protected from impacts or dirt, with obvious advantages in terms of appearance and reliable operation.
According to an alternative embodiment, not illustrated, the first element 5 is fixed to one edge of the door 3 and the second element 6 is fixed to the oven 1 frame 2 at one side of the mouth of the oven.
It is also evident that, in addition to the specific example of use described above, a hinge of the type disclosed may advantageously be used to constrain a generic wing to a respective frame.
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A hinge for wings or doors, in particular of electrical appliances, having a first element, a second element and a rocker lever for connecting the first and second elements; the lever pivots on the second element and has a first arm integral with the first element to render the first and second elements movable relative to one another with a tilting action between a closed position and an open position; the second element consisting of a substantially box-shaped body containing both elastic parts, inserted between the second element and a second arm of the lever to apply an elastic action on the lever, and a damping device, for applying a damping action on the lever during the reciprocal motion of the first and second elements, when the closed position is almost reached.
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DESCRIPTION
1. Technical Field
The technical field of the invention is electrical transducers and in particular miniature electrical microphones for hearing aids.
2. Background Art
The present invention is an improvement on U.S. Pat. No. 4,450,930 entitled "Microphone with Stepped Response" issued to Mead C. Killion. The Killion patent describes an acoustic network whose function is to provide, when incorporated into a microphone, the transduction of sound to an electrical output wherein the higher frequencies have a greater signal level with respect to the lower frequencies. The benefits of such selective adjustment of signal according to frequency for the hearing impaired is described therein.
The Killion patent describes a microphone assembly wherein a housing having a cavity is separated into two principal chambers by a main diaphragm, and further including a microphone transducer element disposed to be actuated by movement of this main diaphragm. Ambient sound is spit at an input port so that a fraction of the sound enters one of the chambers without significant attenuation. The remainder of the incoming sound is passed through a series of relatively short passages and apertures to enter a sealed chamber having a secondary diaphragm forming one wall thereof. Sound entering this second branch ultimately passes through the flexing of this secondary diaphragm to the opposite side of the main diaphragm.
The compliance and mass of the secondary diaphragm, and the dimensions of the passages are chosen so that at relatively low frequency there is relatively little acoustical attenuation in this second branch, with the result that a significant pressure cancellation occurs at the main diaphragm so as to suppress the microphone response at these lower frequencies. At higher frequencies the attenuation in this second branch becomes substantially greater, resulting in a significant reduction of the counterpressure produced by the secondary diaphragm, resulting in substantially increased high frequency output.
The stepped response microphone described in the Killion patent provided the necessary frequency variation of a response, but required in the smallest embodiment an overall case dimension of approximately 4.0 by 5.6 by 2.3 millimeters.
Attempts to further miniaturize microphones of this general design proved unsuccessful beyond a certain limit, principally because of the fact that the relatively short sound-attenuating passages of the second acoustical branch referred to above could not be correspondingly shortened while still providing the desired resonance turnover point, namely a point in the vicinity of 1 kilohertz.
Thus, prior to the instant invention, there remained a need for a microphone providing the general frequency characteristics of the Killion design, while overcoming the above-mentioned disadvantage thereof.
SUMMARY OF THE INVENTION
The present invention is an improvement over the above-mentioned frequency dependent acoustic attenuating network. In the present design only one inlet is required to the microphone case instead of the two necessary in this previous design, thus reducing the necessity for a perfect seal around the sound inlet. It also allows the use of a reduced dimension inlet tube, unlike previous designs wherein the inlet tube diameter and tube flange were necessarily of increased size to feed the second inlet. The present invention is an improvement over the acoustical network in the above-cited patent in that the present design can achieve the same frequency response in a physically smaller unit.
According to a feature of the invention, the secondary diaphragm is disposed to confront the transducer main diaphragm, separating the case into two principal volumes. Ambient sound is admitted to the chamber formed between the two diaphragms, this structure acting as a distributed line rather than a lumped element to provide the acoustic inertia required for the stepped response shape. The structure used is effectively three dimensional rather than two dimensional, and more efficiently uses the reduced volume of a smaller transducer.
According to a related feature of this invention, the principal acoustic structure which provides the stepped response shape lies on the side of the transducer diaphragm opposite the electrical amplifier and connecting circuitry. This placement of the acoustic structure, as opposed to other designs which attempted to adapt U.S. Pat. No. 4,450,930 to systems of reduced dimensions, allows the step in amplitude to occur at the proper frequency of one kilohertz. By means of a unique bypass element around the main transducer diaphragm, the present invention achieves additional high acoustic inertia, while trapping a majority of the volume between the main diaphragm and secondary diaphragm. The placement of the acoustic network in an area other than the rear cover allows this surface to be non-planar, thus freeing this area for other uses such as a support for terminal pads, which further reduces the volume of the microphone.
According to a further feature of the invention, additional acoustical inertia (inertance) is provided in series with the secondary diaphragm to further lower the turnover frequency by sealingly interposing a labyrinth plate between the two diaphragms, the plate having a suitably dimensioned passage coupling sound between the two chambers thus formed. Ambient sound is restricted to enter the chamber formed between the labyrinth plate and the main diaphragm, to pass across this chamber to pass through the labyrinth plate passage, and thereafter to reverse direction to flow across the secondary diaphragm. This increased path length thus additionally contributes to the necessary total inertance.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1A is a cross-sectional side view of the microphone assembly of the present invention.
FIG. 1B is a cut-away side view similar to FIG. 1A, but having components not directly associated with the acoustical paths of the microphone assembly removed, and further showing these paths by directional arrows.
FIG. 2 is a partially cutaway plan view of the microphone assembly shown in FIG. 1A.
FIG. 3 is a side view of the microphone assembly shown in FIG. 1A, but viewed from the opposite side.
DETAILED DESCRIPTION
While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention, and is not intended to limit the broad aspect of the invention to embodiment illustrated.
Referring now to the figures, the structure of the microphone assembly 10 of the present invention comprises a case or housing 12, which, in the embodiment shown is square in shape and has depending walls 14. A plate 16 supports a circuit board 18. An electrical amplifier (not shown) is constructed on this board 18, which carries terminals 26 connected to the amplifier to protrude to the outside.
Two of the corners 28 of the main housing 12 are deformed to act as supports of predefined height (see FIG. 3). Two corners of a special labyrinth plate 30 rest on these supports. The opposite end of this plate 30 has a protrusion which extends into a case inlet 36, thereby forming a three point support. This labyrinth plate 30 generally divides the case into two isolated volumes sealed off from each other except for special acoustical passages, one of which is a hole 34 through the labyrinth plate and disposed generally diametrically opposite the sound inlet 36. An annularly disposed ring 33 glued to the right-hand face of the labyrinth plate 30 as seen in FIG. 1A acts as a spacer for subsequent assembly. This ring 33 has a section removed so as not to impede the flow of sound entering the case inlet 36.
On the left-hand face of the labyrinth plate 30 there is mounted a generally circular cup-shaped secondary diaphragm 38 similar in shape to those proposed in the previously mentioned Killion patent. The distance between the secondary diaphragm 38 and the labyrinth plate 30 is restricted so as to play a role in the overall frequency response of the microphone assembly. An annular flange portion 40 of the secondary diaphragm 38 is glued to the left-hand face of the labyrinth board 30 as shown in FIG. 1A. The secondary diaphragm 38 thus stands at a small distance from the labyrinth plate 30 to form a generally sealed volume therein, except for the acoustical passage.
A main diaphragm assembly consisting of a compliant conducting main diaphragm 42 peripherally attached to mounting ring 44 is affixed to the housing interior by glue fillets 46 to be held in a position where the main diaphragm 42 confrontingly contacts the spacing ring 33. The glue fillets 46 and that portion of the main diaphragm mounting ring 44 in the vicinity of the inlet passage 36 effectively seal off the interior structure of the microphone assembly to the right of the main diaphragm from the inlet passage 36. An electret assembly 49 is mounted (by means not shown) to the mounting ring 44 so as to be in contacting engagement at peripheral portions with the main diaphragm 42.
Referring now to FIG. 1A, FIG. 1B and FIG. 2 it will be seen that sound (indicated by flow arrows F-F) entering through an inlet tube 48 passes through a damping element or filter 50 to provide an inertance and a resistance to the incoming sound, the sound thereafter entering the inlet port 36. Thereafter the incoming sound travels across the chamber 52 (excitation chamber) formed by the main diaphragm 42 and the labyrinth plate 30, thereby providing energization of the main diaphragm 42. Thereafter the sound passes through the small aperture 34 in the labyrinth plate 30 to enter the chamber 54 (transfer chamber) formed between the secondary diaphragm 38 and the labyrinth plate. Excitation of this secondary diaphragm 38 causes sound to be transmitted to the remaining volume 56 defined by the interior surface of the case 12, the secondary diaphragm 38 and the labyrinth plate 30.
Sound received in this chamber is then coupled across through a bypass port 51 (FIG. 2) to enter the volume 58 in the housing lying to the right of the main diaphragm 42 so as to impinge on the rear surface of the main diaphragm 42. This bypass port 51 is made by cutting away a corner of the labyrinth board 30, the diaphragm mounting ring 44 and the spacing ring 33 in the vicinity of one corner of the housing, as shown FIG. 2. As a result, this bypass port 51 transmits sound received from the secondary diaphragm 38 around to the rear (right-hand) surface of the main diaphragm 42.
The dimensions of the various channels, apertures, and ports, the compliances of the two diaphragms 42, 38, the acoustical transmission properties of the damping element 50, and the relative volumes of the various chambers are arranged so that at low frequencies a substantial replication of the pressure excitation delivered to the main diaphragm 42 from the incoming sound is provided via the bypass port 51 to the rear surface of the main diaphragm, thereby materially reducing the excitation pressure in such lower frequency ranges. By this means the microphone is rendered relatively unresponsive to low frequency sound. At higher frequencies, however, significant attenuation of this feed-around occurs because of the frequency-dependent acoustical attenuating properties of the coupling passages, with the result that at these higher frequencies this pressure cancellation effect is largely lost. As a result of this, at these higher frequencies the microphone sensitivity is materially augmented.
Considering the various acoustical elements in more detail, at low frequencies sound is relatively unimpeded by small clearances, and except for the highly complaint secondary diaphragm 38 would be of essentially equal magnitude on both sides of the transducer diaphragm 42. The secondary diaphragm 38 produces a slight sound pressure imbalance of relatively constant magnitude at low frequencies, which results in a low level signal output from the transducer. At a well controlled intermediate frequency the inertia of the air flowing across the main diaphragm 38 and in the remainder of the sound path through the secondary diaphragm causes a resonant condition which acoustically seals off this path for all higher frequencies. This produces a step in the frequency response pattern similar to that proposed by U.S. Pat. No. 4,450,930; however, the present invention differs in the design of the structure necessary to achieve the same response.
As shown in FIG. 1B, the main transducer diaphragm 42 and labyrinth plate 30 form a small cavity 52 of narrow dimension. Unlike the usual microphone, this cavity does not act as a lumped capacitive element, since the hole 34 in the labyrinth plate 30 allows sound traveling the length of the cavity to exit therethrough. As the height of the cavity is small, there is restriction to sound flow along the length of the cavity, which is also acoustically shunted at each point by a portion of the main diaphragm 42. This cavity thus behaves generally as a distributed transmission line. Sound then enters the even more restricted cavity 54 formed between the labyrinth wall 30 and the secondary diaphragm 38, to exit therefrom with modest attenuation thereafter to travel to the opposite surface of the main diaphragm 42 via the bypass port 51.
At higher frequencies this feed-around action is greatly attenuated, such attenuation arising to a considerable degree because of inertial and resistance effects experienced by sound traveling through restricted passages. Inertial effects arise in general from the necessary pressure differential required to accelerate a column of air confined within an acoustical conduit. Quantitatively this phenomenon is referred to as inertance. The inertance per unit length of a given conduit is proportional to the density of air and inversely proportional to the cross-section area of the conduit. Resistance effects are inherently dissipative, and arise from viscous drag at the walls of the conduit, such drag giving rise to a pressure differential. Clearly, at frequencies sufficiently low that inertance effects in a given conduit may be ignored, resistance effects may still play a role. In general, the resistance per unit length of a given conduit will typically be strongly governed by the minimum dimension thereof, e.g., the separation between the main diaphragm 42 and the labyrinth wall 30, and the separation between the secondary diaphragm 38 and the labyrinth wall.
Although the actual equivalent circuit of the microphone assembly 10 is quite complex, certain general observations may nevertheless be made. The first is that the turnover frequency, i.e., the frequency at which the compensating sound pressure that is fed around to the rear of the main diaphragm 42 begins to be severely attenuated, is strongly governed by the product of the compliance of the secondary diaphragm 38 and the effective inertance of the acoustical passages supplying sound energy to it. To a first approximation this inertance may be taken to be the effective inertance of the lower half of the input chamber 52, the inertance of the labyrinth plate port 34, and the inertance of the lower half of the secondary diaphragm cavity 54. The amount of attenuation at frequencies well above the turnover point will also be governed by resistances of the various relevant conduits and ports, as well as the acoustical damper 50.
It is clear that additional resistance and inertance effects may be provided by similarly adjusting the separation between the interior wall of the casing 12 and the secondary diaphragm 38. The labyrinth plate 30 may be eliminated, and the secondary diaphragm 38 may be moved correspondingly closer to the main diaphragm 42; however, the turnover frequency rises as a result of this. By using such a labyrinth plate 30 to add significantly to the acoustical path length, sufficient inertance is provided to achieve the desired stepped frequency response turnover at approximately 1 kilohertz in a reduced dimension microphone assembly, in accordance with a design objective of the instant invention. In the event, that for one reason or another, a significantly higher turnover frequency is desired, then the labyrinth plate 30 may, as mentioned above, be eliminated. Alternatively, multiple labyrinth plates may be employed to increase the labyrinth inertance and/or resistance, if desired.
The response of the microphone assembly described hereinabove is generally stepped, and similar to that of the microphone assembly described in the previously mentioned Killion patent. It has a turnover frequency of approximately 1 kilohertz, rising thereafter by a factor of approximately 20 d.b. at a value of 3 kilohertz. This behavior is, however, achieved in a structure substantially smaller than the Killion structure, for reasons outlined hereinabove. The case dimensions (exclusive of the inlet tube 38) of the assembly shown in the figures are approximately 3.6 by 3.6 by 2.3 millimeters.
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A stepped frequency microphone particularly adapted to a hearing aid application provides a stepped frequency response characteristic relative to frequency, and has a low-pass sonic attenuator for providing to the undriven side of the microphone diaphragm a sonic counterpressure which at low frequencies substantially cancels ambient sound pressure delivered to the drive side of the diaphragm, the attenuator reducing this counterpressure at elevated frequencies to provide accentuated high frequency response.
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FIELD OF THE INVENTION
[0001] The present invention relates to a vacuum processing apparatus having a lid-attached processing vessel for use in a film forming process of, e.g., semiconductor substrate.
BACKGROUND OF THE INVENTION
[0002] Conventionally, a vacuum processing apparatus has been used for performing on a semiconductor substrate, an LCD substrate or the like, various processes such as film forming process, etching, ashing, heat treatment and the like, under a depressurized atmosphere. In such an apparatus, a processing vessel for performing vacuum processing includes a vessel main body having an upper opening, and a lid attached to the vessel main body to be opened or closed. Further, as for this kind of apparatus, it has been known that a lid is rotatably attached to the vessel main body around the horizontal axis line through a hinge or the like.
[0003] For example, an opening/closing lid hinge mechanism of a vacuum processor has been known, wherein a gear mechanism is configured to open or close a lid around a horizontal axis line along a longitudinally elongated elliptic path (for example, see Japanese Patent Laid-open application No. H11-101345 (particularly, FIG. 2)). By this mechanism, the lid can be opened or closed without being overhung at the outside of the vessel main body.
[0004] Further, a vacuum processor including a slide mechanism for horizontally sliding a lid and a rotation mechanism for rotating the lid around the horizontal axis line has been known (for example, see Japanese Patent Laid-open Application No. 2001-185534 (particularly FIG. 6)). By using this mechanism, maintenance becomes easier, and at the same time, attaching or detaching a heavy object to or from the lid can be readily carried out.
[0005] However, in the former technology, a complicated mechanism needs to be provided to track the longitudinally elongated elliptic path during the opening or closing operation. Further, multiple or large-scale mechanism(s) need to be disposed around the lid to perform the sliding or rotational operation. Accordingly, the processor becomes expensive and large sized.
[0006] Still further, in these technologies, since the lid is rotated around the horizontal axis line to fully open the vessel main body, such a configuration cannot be adopted that a part of the processor (e.g., source material supply system) is disposed above the lid. As a result, not only is the foot print of the processor increased, the capability to maintain it is also undermined.
[0007] Still further, recently, there is a demand for a vacuum processing apparatus, wherein a source gas is produced by vaporizing a liquid source material or sublimating a solid source material, and is then supplied into a processing vessel. In this kind of apparatus, the conductance of a line provided between the source material vessel and the processing vessel has to be increased to ensure a supply amount of source gas, or to smoothly supply the source gas into the processing vessel. For this, the line provided between the source material vessel and the processing vessel must have a large diameter and short in length. However, in the configuration of the conventional apparatus, the line provided between the source material vessel and the processing vessel could not be made short.
[0008] Further, in the aforementioned technologies, since the lid is rotated around the horizontal axis line, if the source material vessel is fixed on the lid, the source material vessel will be tilted and thus, the source material accommodated therein is also tilted and cause other changes on the source material. Accordingly, a proper supply amount of source material cannot be achieved.
SUMMARY OF THE INVENTION
[0009] It is, therefore, an object of the present invention to provide a vacuum processing apparatus of simple configuration that can be configured at low cost, wherein other component part, such as source material supply system and the like, may be disposed above the lid.
[0010] Further, it is an object of the present invention to provide a vacuum processing apparatus capable of having a short pipeline distance between a source material vessel and a processing vessel.
[0011] Still further, it is an object of the present invention to provide a vacuum processing apparatus capable of realizing such a configuration where the state of source material is not changed by opening or closing of the lid.
[0012] In accordance with a preferred embodiment of the present invention for achieving the aforementioned objects, there is provided a vacuum processing apparatus including: a processing vessel whose inside can be depressurized, the processing vessel including a vessel main body having an upper opening and a lid for airtightly closing the upper opening of the vessel main body; and a lid support mechanism for opening or closing the upper opening of the vessel main body by moving the lid, wherein the lid support mechanism allows the lid to be translated in a vertical direction, and to be rotated around a vertical axis line disposed at a peripheral position of the lid when the lid is elevated from the vessel main body.
[0013] In this way, the lid is translated upward and then rotated around the vertical axis line, to thereby be dislocated from the vessel main body. Therefore, the upper opening of the vessel main body can be opened. Here, since the lid is translated upward and then rotated around the vertical axis line, other component part may be disposed at a position above the lid, which was dead space conventionally. Further, the lid support mechanism may be formed of supporting structure, which is installed coaxially on the vertical axis line, so that the configuration thereof need not be complicated and large sized. Still further, since the processing vessel can be opened while maintaining the lid's orientation at horizontal position, the source material therein may not be affected when the processing vessel is opened, even in case where the source material vessel is fixed on the lid.
[0014] Meanwhile, same as in the conventional art, if the lid is opened around the horizontal axis line, it is largely rotated upward, and thus, it being tilted or reversed. For the same reason, it is impossible to dispose a part of the processor above the lid, or to fix the source material vessel on the lid.
[0015] Further, it can be configured such that if the lid is not elevated at a predetermined height, it is not allowed to rotate. By doing this, the vessel main body or the lid can be prevented from being damaged due to erroneous manipulation.
[0016] In the present invention, the lid support mechanism may be configured to maintain the lid at a predetermined height while the lid is rotated. By doing this, a height-maintaining operation of the lid becomes unnecessary during the rotation thereof, so that it is possible to carry out the rotating operation safely and more readily.
[0017] In the present invention, the lid support mechanism may have a supporting member for supporting the lid directly or indirectly, wherein the supporting member is extended substantially horizontally above the lid from the vicinity of the vertical axis line. Therefore, it is possible to maintain the pose or position of the lid with high accuracy.
[0018] In the present invention, a lifting unit for upwardly lifting the lid may be further included. By using this, in case of elevating the lid, it is possible to carry out such an elevating operation with small force, and thus, more easily.
[0019] In the present invention, a source material vessel, disposed above the lid, for accommodating therein a source material supplied into the processing vessel may be further included. In this way, the pipeline distance between the source material vessel and the processing vessel can be short, and at the same time, the diameter of line can be large without increasing the foot print. Thus, the conductance of line between the source material vessel and the processing vessel can be large. For the same reason, in case where the source gas obtained by vaporizing the liquid source material or sublimating the solid source material is supplied into the processing vessel, the amount of source gas to be supplied can be ensured sufficiently. Further, the source gas can be prevented from being changed while supplying it, so that high quality processing can be performed.
[0020] In the present invention, it is preferred that the source material vessel is immovably disposed with respect to the lid. By doing this, for example, the supply line between the source material vessel and the lid can be configured to be fixed, and therefore, the apparatus may have more simple configuration.
[0021] Further, a source material supply line for supplying a source material from an upper portion of the lid into the processing vessel through the lid may be included. By using this, the lid is maintained at the horizontal position during the opening or closing operation thereof, so that the source material supply line may be connected to the lid without causing any problems. Hence, the source material supply line may be fixed to the lid, and further, the position thereof is not changed.
[0022] In this case, a gas supply line extended through the lid to the upper portion thereof and connected to the source material supply line may be further included.
[0023] Further, the vacuum processing apparatus may include any apparatus, which performs any processings at the state where the processing vessel is depressurized. For example, film forming apparatus such as CVD, etching apparatus such as dry etching, ashing apparatus such as plasma asher, heat treating device such as annealing furnace, etc., may be enumerated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 offers a schematic view showing a preferred embodiment of a vacuum processing apparatus in accordance with the present invention;
[0025] FIG. 2 provides a plane perspective view of the apparatus described in FIG. 1 ;
[0026] FIG. 3 is a cross sectional view showing main parts of an opening/closing supporting unit in the apparatus described in FIG. 1 ; and
[0027] FIG. 4 presents a perspective view schematically showing line configuration of the apparatus described in FIG. 1 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] A Preferred embodiment of a vacuum processing apparatus in accordance with the present invention will be described in detail with reference to the accompanying drawings.
[0029] FIG. 1 is a schematic view showing an overall configuration of a vacuum processing apparatus 100 in accordance with the present embodiment. The vacuum processing apparatus 100 includes a processing vessel 110 , a source material supply system 120 , a lid support mechanism 130 and a gas exhaust system 140 .
[0030] The processing vessel 110 contains a vessel main body 111 having an upper opening 111 a, and a lid 112 for hermetically closing the upper opening 111 a of the vessel main body 111 .
[0031] Further, in the vessel main body 111 , a processing table 113 for supporting thereon an object to be processed, such as semiconductor wafer or the like (not shown), is disposed. A source material discharging head (shower head) for discharging a source material (source gas) into the processing vessel 110 is installed at a bottom surface of the lid 112 .
[0032] The source material supply system 120 is disposed above the lid 112 . The source material supply system 120 includes a source material supply box 121 having a source material vessel 122 accommodating therein a source material (liquid or solid in the present embodiment) and a source material supply line 123 for supplying a source material (source gas in the present embodiment), which is connected to the source material vessel 122 . Further, a control unit 120 A for controlling the source material supply status may be installed in the source material supply system 120 .
[0033] The source material supply line 123 is connected to a discharging head 112 A through the lid 112 . A source material replacement valve 123 a and a source material supply valve 123 b are provided in the source material supply line 123 . Further, a gas discharge line 124 is connected to the source material supply line 123 . A discharge valve 124 a is installed in the gas discharge line 124 . The gas discharge line 124 penetrates the lid 112 and the vessel main body 111 to communicate with the outside of the vessel main body 111 . Further, one or more gas supply line(s) 125 is (are) connected to the source material supply line 123 . A gas supply valve 125 a is installed in the gas supply line 125 .
[0034] The gas supply line 125 involves supplying carrier gas or cleaning gas for cleaning each line or processing vessel. As schematically shown in FIG. 4 , the gas supply line 125 is introduced from the outside into the vessel main body 111 , and penetrates the lid 112 to be introduced into the source material supply box 121 , to thereby be connected to the source material supply line 123 . Further, in FIG. 4 , the lid support mechanism 130 and others as well as valves of respective lines are properly omitted.
[0035] Returning again to FIG. 1 , a lid support member 131 is disposed above the lid 112 . The lid support member 131 supports the lid 112 directly or indirectly. The lid support member 131 is connected to a driving member 132 , which is rotatably supported with respect to a shaft 133 inserted therein. More specifically, as shown in FIG. 3 , a bearing 132 a, e.g., cross roller bearing or the like, is interposed between the driving member 132 and the shaft 133 , and the driving member 132 is configured to be fixed along the direction of axis line while it is to be rotated around the axis line, with respect to the shaft 133 .
[0036] The axis line (vertical axis line) of the shaft 133 is disposed at a peripheral position of the lid 112 (position other than the center), e.g., right outside the lid 112 in the present embodiment.
[0037] The shaft 133 is elevatably supported with respect to a fixed member 134 fixed on the vessel main body 111 . To be more specific, as shown in FIG. 3 , the fixed member 134 has a guide unit 134 a, e.g., ball spline or the like, for fixing the shaft 133 so that it can be moved along the direction of the axis line but cannot be rotated around the axis line.
[0038] As mentioned above, the lid support mechanism 130 allows the lid 112 to be translated in the normal direction to the vessel main body 111 , and be rotated around the vertical axis line disposed at the peripheral position of the lid 112 .
[0039] At a lower portion of the fixed member 134 , a lifting unit 135 for upwardly moving the shaft 133 is installed. As described in FIG. 3 , the lifting unit 135 applies lifting force to the shaft 133 by using a resilient member 135 a, e.g., constant force spring or the like. Further, the lid 112 is configured to be readily elevated by the lifting unit 135 .
[0040] In the present embodiment, the source material supply box 121 is upwardly supported by the lid support member 131 . Further, the lid 112 is supported by brackets 138 attached to the source material supply box 121 . FIG. 2 illustrates such a state in detail. FIG. 2 shows a top view of the vacuum processing apparatus 100 , and at the same time, perspective views of the source material supply box 121 and the lid 112 . FIG. 2 basically shows a state where the vessel main body 111 is closed by the lid 112 ; and at the same time, it shows as a dashed double-dotted line a state where the lid 112 is opened (rotated state).
[0041] Here, plural (three in the drawing) brackets 138 are provided to support the lid 112 , which is suspended from the source material supply box 121 . As mentioned above, in this embodiment, the lid support member 131 indirectly supports the lid 112 through the source material supply box 121 and the brackets 138 .
[0042] At the lid support member 131 , plural horizontal position adjusting mechanisms 139 formed of positioning screws, dial gauge and the like are installed. By these horizontal position adjusting mechanisms 139 , the lid 112 supported indirectly by the lid support member 131 as described above can be positioned in the horizontal direction. To be more specific, position or direction of the lid 112 on a the horizontal plane can be adjusted by the plural horizontal position adjusting mechanisms, which carry out positioning at various positions in the horizontal direction (in the drawing, two horizontal position adjusting mechanisms ( 139 , 139 ), which perform positioning in different directions normal to each other).
[0043] Further, at the lid support member 131 , plural vertical position adjusting mechanisms 131 a for adjusting the vertical position of the lid 112 are installed. The height of the lid 112 may be adjusted by these vertical position adjusting mechanisms 131 a. Moreover, the height of the lid 112 is adjusted by using the plural vertical position adjusting mechanisms 131 a, which are separated from each other in the horizontal direction, so that the inclination level of the lid 112 is adjusted.
[0044] To be more specific, each of the vertical position adjusting mechanisms 131 a attached to the lid support member 131 is configured to adjust the height of the source material supply box 121 with respect to the lid support member 131 , and thus, adjusting the height of the lid 112 indirectly.
[0045] At the lid support mechanism 130 , a rotation lock unit (plunger) 132 c for fixing the rotation of the lid 112 is installed. The rotation lock unit (plunger) 132 c fixes the driving member 132 and the shaft 133 in the rotation direction all the time, and such locked state is released by performing a predetermined operation (e.g., unloading operation).
[0046] Further, there is installed a raised position keeping unit for keeping the lid 112 at a raised position of predetermined height when the lid 112 is elevated from the vessel main body 111 . As described in FIG. 1 , the raised position keeping unit includes a supported material 137 (in the drawing, corresponding to a rotatably supported roller), which is attached to the driving member 132 through a fitting member 136 ; and a supporting surface 134 b (a top surface of the fixing member 134 ) for upwardly supporting the supported material 137 .
[0047] As shown by the solid line in FIG. 2 , in the state where the lid 112 is disposed on the vessel main body 111 (the upper opening 111 a of the vessel main body 111 is closed or it is disposed at a raised position right above the vessel main body 111 ), the supported member 137 is not supported by the supporting surface 134 b in the side of the fixing member 134 . Contrary to this, if the lid 112 disposed at the raised position is rotated by a predetermined angle in the horizontal direction, the supported member 137 reaches to the supporting surface 134 b of the fixing member 134 . In such a state, if the lid 112 is further rotated in the horizontal direction, the supported member 137 moves on the supporting surface 134 b (while rotating, in case of a roller).
[0048] As mentioned above, since the supported member 137 is supported on the supporting surface 134 b, the lid 112 is supported at a predetermined height during the rotation thereof. Further, a stepped portion 134 c is formed in the supporting surface 134 b to confine the rotation range of the lid 112 .
[0049] Here, if the lid 112 tends to rotate when it is not elevated at a predetermined height, the supported material 137 will contact the side of the fixing member 134 . Accordingly, even though the rotation lock unit 132 c is not provided or the rotation lock unit 132 c is released, it is possible to control the lid 112 not to rotate if it does not reach a predetermined height.
[0050] As shown in FIG. 2 , the aforementioned gas exhaust line 124 and the gas supply line 125 are respectively opened around the upper opening 111 a on the top surface of the vessel main body 111 . The gas exhaust line 124 is connected to the gas exhaust system 140 shown in FIG. 1 . Further, in the gas exhaust system 140 , a gas exhaust unit such as a turbo molecular pump 143 , a dry pump 144 or the like is installed. Still further, a bypass line 142 or valve 141 a or 142 a may be disposed, if necessary. Still further, the gas supply line 125 is to introduce from the processing vessel 110 into the source material supply box 121 through the lid 112 various gases, which have been supplied into the processing vessel 110 from the outside.
[0051] In the following, operation and effect of the vacuum processing apparatus 100 as configured above will be explained.
[0052] When the processing vessel 110 is opened in the vacuum processing apparatus 100 , first, the lid 112 is elevated from the vessel main body 111 manually or by using any driving source (electric motor, fluid pressure cylinder, etc.). At this time, the rotation of the lid 112 is controlled by control structure such as the rotation lock unit 132 c, the supported material 137 or the like, until the lid 112 is disposed at a predetermined height. Accordingly, it is possible to carry out safe and easy manipulation in case of performing, e.g., manual operation. Further, at this time, the lid 112 can be elevated, i.e., translated upward while being supported and basically maintaining its orientation (at horizontal position).
[0053] If the lid 112 is elevated to a predetermined height, it is rotated around the shaft 133 (vertical axis line), and thus, being dislocated from the vessel main body 111 in the horizontal direction as described in FIG. 2 . At this time, since the supported member 137 is placed and supported on the supporting surface 134 b of the fixing member 134 , the height of rotating lid 112 is kept during the rotation thereof even though it is not supported.
[0054] FIG. 2 shows as a dashed double-dotted line a state where the lid 112 is fully opened. In such a state, the lid 112 and the source material supply box 121 are not disposed above the vessel main body 111 , so that maintenance (cleaning or repair of equipment) of the processing vessel 110 can be performed very easily.
[0055] In the vacuum processing apparatus 100 of the present embodiment, the source material supply system 120 is disposed at a position right above the lid 112 , which was dead space conventionally. Therefore, the overall apparatus can be made compact. Further, it is possible to directly supply the source material into the processing vessel 110 from the upper portion, to thereby shorten the source material supply line while increasing the line's conductance. Hence, the amount of source material to be supplied can be maintained steadily, and at the same time, the source material can be prevented from being changed while supplying it. Accordingly, the processing can be performed by using various source materials smoothly.
[0056] To be more specific, in case where the source gas is discharged from the source material vessel 122 by vacuum-exhaustion of the processing vessel 110 by the gas exhaust system 140 , if conductance of the source material supply line 123 is low, the amount of source gas to be supplied cannot be kept or the source gas may be changed in the supply line. However, in the present embodiment, it is possible to avoid such a problem by increasing conductance of the source material supply line 123 .
[0057] Particularly, in the present embodiment, since the source material supply system 120 is fixed on the lid 112 , the lid 112 and the source material supply system 120 can be rigidly coupled to each other. Accordingly, the configuration can be simplified, and at the same time, the source gas can be prevented from being contaminated. Further, in the present embodiment, in case of performing vacuum-exhaustion of source material vessel 122 or various lines, vacuum level may be increased.
[0058] For example, if the source material is solid, it is sublimated to produce source gas, which is supplied into the processing vessel 110 . In this case, it may be difficult to maintain the amount of source gas to be supplied, depending on the characteristics of the source material. However, in the present embodiment, the length of source material supply line 123 can be reduced, and the diameter of line can be large without interfering with surrounding structures. For the same reason, the amount of source gas to be supplied can be ensured, and thus, the processing can be performed smoothly.
[0059] Further, when vaporizing liquid source material other than organic metal and supplying it from the supply line 123 into the processing vessel 110 , if the conductance of supply line 123 is small, the source material may be liquefied or decomposed in the line. If the liquefied or decomposed product is supplied into the processing vessel, the processing quality may be degraded. However, in the present embodiment, since the conductance of supply line is increased, the source material supply condition can be improved and high quality processing can be performed.
[0060] In the present embodiment, since the position of the lid 112 is not changed during the opening or closing thereof, the source material vessel 122 can be disposed above the lid 112 without causing any problem. Further, even though the lid 112 and the source material vessel 122 are fixed to each other, the status of source material accommodated in the source material vessel 122 is not changed, i.e., the source material is not tilted in the source material vessel 122 , since the position of the source material vessel 122 is not changed. Therefore, the supply amount of source material and the supply status may be stabilized.
[0061] In the present embodiment, the length of the source material supply line 123 may be set in the range of 30˜100 cm, and practically, about 70˜80 cm. Further, the line diameter may be configured in the range of 20˜80 mm, and preferably, large diameter of 30˜50 mm may be employed.
[0062] In the present embodiment, the vacuum processing apparatus has a depressurized processing vessel, in which any processings may be carried out. As for the vacuum processing apparatus, film forming apparatus such as CVD, etching apparatus such as dry etching, ashing apparatus such as plasma asher, heat treating device such as annealing furnace or the like, may be enumerated.
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A vacuum treating device, comprising a treatment container having a container body ( 111 ) and a lid ( 112 ) and allowing an internal pressure to be reduced and a lid support mechanism ( 130 ), wherein an upper opening ( 111 a ) formed in the container body can be closed airtight by the lid ( 112 ). The lid support mechanism ( 130 ) opens and closes the upper opening ( 111 a ) of the container body by moving the lid ( 112 ) so as to be translatingly moved in the vertical direction and, when the lid ( 112 ) is moved upward from the container body ( 111 ), supports the lid ( 112 ) so as to be rotated around a vertical axis disposed around the lid.
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BACKGROUND INFORMATION
[0001] German Patent Application No. DE 100 32 022 describes a method for determining the activation voltage for a piezoelectric actuator of an injector, which provides for first measuring the pressure prevailing in a hydraulic coupler indirectly, prior to the next injection event. The pressure is measured in that the piezoelectric actuator is mechanically coupled to the hydraulic coupler, so that the pressure induces a corresponding voltage in the piezoelectric actuator. This induced voltage is used prior to the next injection event to correct the activation voltage, inter alia, for the actuator. An induced voltage that is too low is indicative of a missed injection. The injector is preferably used for injecting fuel for a gasoline or diesel engine, in particular for common-rail systems. In this context, the pressure prevailing in the hydraulic coupler also depends, inter alia, on the common-rail pressure, so that the activation voltage is varied as a function of the common-rail pressure. The voltage requirement of a piezoelectric actuator depends first and foremost on the pressure prevailing in the valve chamber, as well as on the coefficient of linear expansion of the piezoelectric actuator. The voltage required for properly operating the injector at one operating point is the so-called voltage requirement, i.e., the relationship between voltage and lift at a specific force which is proportional to the common-rail pressure.
[0002] German Patent No. DE 103 15 815.4 discusses deriving the active voltage requirement of an injector from the voltage difference between the maximum actuator voltage and the final steady-state voltage.
[0003] It is problematic in this regard, however, that the voltage requirement of an injector drifts over the service life of the injector. The effect of this drift is that the actuator voltage that is predefined as a function of one operating point does not ensure a proper operation of the injector at a predefined operating point. This leads to errors in the injection quantity which, in turn, cause negative exhaust-emission levels and negative noise emissions. In the least favorable case, a failure of the injection and thus of the injector may even occur, namely when the lift no longer suffices for opening an injection-nozzle needle.
[0004] Therefore, an object of the present invention is to compensate for this voltage requirement drift.
SUMMARY OF THE INVENTION
[0005] This objective is achieved by a method for determining the activation voltage of a piezoelectric actuator of an injector. The method according to the present invention makes it possible to compensate for the voltage requirement drift by adapting the setpoint voltage value, thereby ensuring that the required, nominal actuator excursion is attained and ensuring a proper and desired operation of the injector over the entire lifetime. In addition, by adapting the voltage requirement, the advantage is derived, in principle, that a very high voltage allowance is not needed for the activation, so that a considerable benefit is gained with respect to the power input/power loss. Moreover, the adaptation of the voltage requirement may also be used for diagnostic purposes, for example in order to output an error message in response to an unacceptably high drift of the voltage requirement.
[0006] The control of the voltage requirement drift is advantageously carried out during one driving cycle of a vehicle having the internal combustion engine, correction values ascertained during the driving cycle being stored in a non-volatile memory. This makes it feasible, in particular, for the correction values stored in the memory to be used in a later driving cycle, as initialization values for a further compensation of the voltage requirement drift.
[0007] To ensure that an adaptation is only carried out in response to an actual voltage requirement drift, i.e., that no readjustment is made in response to only temporary, relatively small deviations, caused, for example, by temperature effects, an enable logic is preferably provided, which enables an adaptation of the voltage requirement drift as a function of parameters characterizing the internal combustion engine and/or the injector.
[0008] These parameters include, for example, the temperature of the internal combustion engine and/or the common-rail pressure and/or the steady state of the voltage control and/or the state of the charging time control and/or the steady state of other secondary feedback control circuits and/or the number of injections and/or the control (activation) duration and/or the injection sequence per combustion cycle, i.e., effectively, the injection pattern (preinjection(s), main injection, post injection(s)).
[0009] The voltage requirement is compensated at various operating points very advantageously with respect to the common-rail pressure, the correction values being stored in correction characteristics maps, which are then also stored in the non-volatile memory, for example in an E 2 -PROM.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows the schematic design of an injector known from the related art.
[0011] FIG. 2 schematically illustrates a graphic representation of the actuator voltage over time, during one activation.
[0012] FIG. 3 schematically shows a block diagram of a control system that utilizes the method according to the present invention.
DETAILED DESCRIPTION
[0013] FIG. 1 schematically depicts an injector 1 , known from the related art, having a central bore. In the upper part, an actuating piston 3 having a piezoelectric actuator 2 is introduced into the central bore, actuating piston 3 being fixedly coupled to actuator 2 . A hydraulic coupler 4 is upwardly delimited by actuating piston 3 , while in the downward direction, an opening having a connecting channel to a first seat 6 is provided, in which a piston 5 having a valve-closure member 12 is situated. Valve-closure member 12 is designed as a double-closing control valve. It closes first seat 6 when actuator 2 is in the rest phase. In response to actuation of actuator 2 , i.e., application of an activation voltage Ua to terminals +, −, actuator 2 actuates actuating piston 3 and, via hydraulic coupler 4 , presses piston 5 having closure member 12 toward a second seat 7 . Disposed in a corresponding channel, below the second seat, is a nozzle needle 11 , which closes or opens the outlet in a high-pressure channel (common-rail pressure) 13 , depending on which activation voltage Ua is applied. The high pressure is supplied by the medium to be injected, for example fuel for a combustion engine, via a supply channel 9 ; the inflow quantity of the medium in the direction of nozzle needle 11 and hydraulic coupler 4 is controlled via an inflow throttling orifice 8 and an outflow throttling orifice 10 . In this context, hydraulic coupler 4 has the task, on the one hand, of boosting the lift of piston 5 and, on the other hand, of uncoupling the control valve from the static temperature-related expansion of actuator 2 . The refilling of coupler 4 is not shown here.
[0014] The mode of operation of this injector is explained in greater detail in the following. In response to each activation of actuator 2 , actuating piston 3 is moved in the direction of hydraulic coupler 4 . Piston 5 having closure member 12 , moves toward second seat 7 . In the process, a portion of the medium, for example of the fuel, contained in hydraulic coupler 4 is forced out via leakage gaps. For that reason, hydraulic coupler 4 must be refilled between two injections, in order to maintain its operational reliability.
[0015] A high pressure, which in the case of the common-rail system may amount to between 200 and 2000 bar, for example, prevails across supply channel 9 . This pressure acts against nozzle needle 11 and keeps it closed, preventing any fuel from escaping. If actuator 2 is actuated at this point in response to activation voltage Ua and, consequently, closure member 12 moved toward the second seat, then the pressure prevailing in the high-pressure region diminishes, and nozzle needle 11 releases the injection channel. P 1 denotes the so-called coupler pressure, as is measured in hydraulic coupler 4 . A steady-state pressure P 1 , which, for example, is 1/10 of the pressure prevailing in the high-pressure portion, ensues in coupler 4 , without activation Ua. Following the discharging of actuator 2 , coupler pressure P 1 is approximately 0 and is raised again in response to refilling.
[0016] At this point, the lift and the force of actuator 2 correlate with the voltage used for charging actuator 2 . Since the force is proportional to the common-rail pressure, the voltage for a required actuator excursion must be adapted as a function of the common-rail pressure to ensure that seat 7 is reliably reached. The voltage required for properly operating the injector or injector 1 at one operating point is the so-called voltage requirement, i.e., the relationship between voltage and lift at a specific force which is proportional to the common-rail pressure. German Patent No. DE 103 15 815.4 discusses how the individual, active voltage requirement of an injector can be derived from the voltage difference between the maximum actuator voltage and the final steady-state voltage.
[0017] This voltage requirement drifts over the lifetime of injector 1 . The effect of this drift is that the actuator voltage that is predefined as a function of one operating point no longer ensures a proper operation of injector 1 at the specified operating point, which leads to errors in the injection quantity, thereby entailing consequences for exhaust-emission levels/noise emissions, culminating in a failure of the injector, namely when the lift no longer suffices for opening nozzle needle 11 . The method described in the following makes it possible to compensate for this voltage requirement drift on an injector-specific basis.
[0018] An idea underlying the present invention is to compensate for the voltage requirement drift by adapting the setpoint voltage value, thereby ensuring that the required, nominal actuator excursion is attained and enabling the proper and desired operation of injector 1 to be ensured over its entire lifetime. Thus, on the one hand, the functioning of actuator 2 is ensured, but on the other hand the injection quantity errors described above are also avoided.
[0019] In principle, by adapting the voltage requirement in this manner, the need is also eliminated for activation processes that require a very high voltage allowance. This is advantageous, in particular, with respect to the power input/power loss of a control system. Moreover, actuator 2 is subject to less wear, since there is no need for actuator 2 to be operated over an entire lifetime with a very large voltage allowance, which is associated with too high of a power surplus in the valve seat.
[0020] Moreover, by monitoring the correction intervention of the adaptation, a diagnostic may also be performed on the entire injector, for example when an unacceptably high drift of the voltage requirement is ascertained.
[0021] The adaptation of the voltage requirement drift is based on automatically controlling the voltage difference between cutoff-voltage threshold U cutoff and the measured, final steady-state voltage U control (compare FIG. 2 ), in an injector-specific manner, to a setpoint value ΔU setpoint which is required for one operating point and which correlates with the required actuator excursion of an injector that has not drifted, i.e., that is performing nominally. This control intervenes correctively by adapting the setpoint actuator voltage in an injector-specific manner, as is described in greater detail below in conjunction with FIG. 3 .
[0022] An actuator setpoint voltage U setpoint is calculated in an arithmetic logic unit 310 . During the driving cycle, difference ΔU actual between cutoff voltage U cutoff and control voltage U control is continually determined. This difference ΔU actual is compared to a predefined quantity ΔU setpoint , the difference between quantity ΔU setpoint and ΔU actual being determined in a node 320 . This difference e ΔU forms the input quantity for a PI controller, for example, in which various controllers 331 , 332 , 33 n are provided for each of the individual cylinders. In these controllers, cylinder-specific correction signals S 1 , S 2 , S n are defined in each instance and output, n describing the number of cylinders.
[0023] The correction values are either multiplied by setpoint voltage U setpoint determined in arithmetic logic unit 310 or, alternatively, added to it, as indicated by nodes 341 , 342 . The thus ascertained corrected values U setpointcorr are fed to an actuator-voltage control device 350 , which determines cutoff-voltage threshold U cutoff . At this point, this cutoff-voltage threshold U cutoff is utilized, together with the ensuing final steady-state voltage U control , in turn, to determine difference ΔU actual .
[0024] Correction values S 1 , S 2 , . . . S n learned during one driving cycle are preferably stored following termination of the driving cycle in a non-volatile memory 360 , for example in an E 2 -PROM, and used before the beginning of the subsequent driving cycle as initialization values for the further adaptation, as schematically depicted in FIG. 3 by an arrow 362 denoted by “INIT”. It is noted at this point that, to calculate voltage difference ΔU actual for the method described above, maximum voltage U max (compare FIG. 2 ) cannot be used, as described in German Patent No. DE 103 15 815.4, but rather cutoff-voltage threshold U cutoff , since U max is not available as a usable quantity in a generally known engine control unit, in which this control is also executed. The voltage requirement drift is also compensated, however, when the cutoff voltage U cutoff quantity is used.
[0025] To ensure that the adaptation is only carried out in response to an actually existing voltage requirement drift, i.e., that controllers 331 , 332 , 33 n only control in this case and not, for instance, in response to temporary, relatively small deviations, caused, for example, by temperature effects, by the dynamic operation, etc., an enable logic circuit is provided in a circuit unit 370 , which monitors typical parameters for enabling the adaptation. These parameters of the internal combustion engine and/or of the injector include, for example, the temperature of the internal combustion engine and/or the common-rail pressure and/or the steady state of the voltage control and/or the state of the charging time control and/or the steady state of other secondary feedback control circuits and/or the number of injections and/or the control (activation) duration and/or the injection sequence per combustion cycle, i.e., effectively, the injection pattern (preinjection(s), main injection, post injection(s)). A steady state of the voltage control is verified, for example, by comparing quantities U setpointcorr and U control . Only if U setpointcorr and U control conform, are PI controllers 331 , 332 . . . 33 n enabled by circuit unit 370 , so that difference ΔU actual may be adapted to ΔU setpoint , as described above, thereby making it possible for the voltage requirement drift to be adapted.
[0026] If, on the other hand, the test reveals that the actuator voltage control is not steady-state, thus, when U setpointcorr deviates from U control , PI controllers 331 , 332 , . . . 33 n are deactivated by enable-logic circuit unit 370 , and correction values S 1 , S 2 , . . . S n remain unchanged, i.e., are, to a certain extent, frozen. The setpoint voltage value continues to be corrected at switching points 341 / 342 using values S 1 , S 2 , . . . S n learned up to that point. Such a “freezing” of the correction values is possible since the injector drift occurs very slowly.
[0027] The method described above may initially be carried out only at one operating point (common-rail pressure), and the acquired correction values used for all operating points. To enhance the accuracy, the method may also be carried out at a plurality of different operating points (common-rail pressures).
[0028] Moreover, it should be pointed out that the comparison of an injector-specific correction value S 1 , S 2 , . . . S 3 , which represents a measure of the deviation of the voltage requirement from the standard, to a predefinable threshold value, may additionally be used for diagnostic purposes. In this manner, it is possible to diagnose the system including actuator 2 , coupler 4 , and the control valve, which is constituted of valve-closure member 12 .
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A method for determining the activation voltage of a piezoelectric actuator of at least one injector which is used to inject a liquid volume under high pressure into a cavity, in particular into a combustion chamber of an internal combustion engine, the activation voltage being varied as a function of the pressure used to pressurize the liquid volume. A drift of the activation voltage (voltage requirement) required for a predefined lift of a control valve of the injector is controlled on an injector-specific basis by controlling the difference between the cutoff-voltage threshold and the final steady-state voltage to a setpoint value predefined for one operating point.
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This application is a continuation application of the U.S. patent application Ser. No. 12/413,904, filed Mar. 30, 2009, which is a continuation application of Ser. No. 11/958,809, filed Dec. 18, 2007, now U.S. Pat. No. 7,530,763, which is a continuation application of the U.S. patent application Ser. No. 10/597,910, filed Aug. 11, 2006, now U.S. Pat. No. 7,419,330, which is a National Stage Entry of International Patent Application No. PCT/GB2005/000447, filed Feb. 9, 2005, filed Feb. 9, 2005, which claims priority to United Kingdom Patent Application No. 0403109.2, filed Feb. 12, 2004. The entirety of all of the aforementioned applications is incorporated herein by reference.
FIELD
This invention relates to apparatus for the creation of outer surfaces having certain effects for structures. In particular, the invention relates to gabion facades and to gabion inserts.
BACKGROUND
In European Patent No. 0466726, there is set forth a cage structure useful in connection with the creation of building blocks, which can be used for sea defences, shoring hillsides, and for providing military defence walls. These structures are made of open mesh panels, for example of welded mesh material, or twisted wire construction. The advantage of the structure set forth is that the panels are used to form the walls of the structure, with the panels being pivotally connected under factory conditions and the structure can be folded to a flat collapsed condition for transportation to site. On site, simply by manipulation, the structure is capable of being moved from the collapsed condition to an erected condition, in which the structure defines a row of open topped cavities which can be filled with soil, sand, rubble or the like to form a wall (or part thereof), shoring block or the like. The invention has been successful commercially on a worldwide basis.
The type of gabion described in EP-B-0466726 has applications in the military field, as well as in civil and environmental defence. Other types of gabion have applications in landscape design and in decorative or aesthetic connections, such as garden ornaments or window boxes. It may be desirable in some circumstances to provide such gabions with a surface effect which allows the gabion fill material to be obscured from view by a surface effect material in use of the gabion.
As well as aesthetic reasons for providing a surface effect, a problem which has been encountered with some gabions is that in certain climates, particularly hot climates, the material which is used to fill the cavities formed by the panels can be susceptible to changing conditions under temperature extremes. For example the material may be caused to contract in cold weather or expand in hot weather which can cause the structure to be less rigid or threaten to “burst” the joins between the panels.
A further problem is that in certain instances it can be desirable to provide a building structure with a particular surface effect, which it might not otherwise have from the material used to fill the cavities.
It should be clear that the invention can be applied to other building structures and situations. This should be borne in mind despite the fact that in the following a structure of the type described in the applicant's patent EP0466726 is given as a particular embodiment of the invention. Other types of gabion are particularly susceptible to improvement with this invention.
In a collapsible/erectable structure it is difficult to give the walls, or one wall a different surface effect than would be achieved as a result of the materials used for the structure and the filling material. It is disclosed in the said patent that when the structure is erected and filled, the walls can be given a different surface effect by the spraying of decorative synthetic resin onto the walls of the erected structure. However, it may be desirable that the walls were to have a different surface effect, say of aesthetically attractive materials such as pebbles, turf or of other vegetation effect, or a surface effect for protective purposes that could not be achieved with the structure specifically described in the said patent.
SUMMARY
The present invention provides an apparatus whereby an outer surface can be provided, which is other than the surface which would be achieved without the invention with the located surface effect being of advantage from an appearance effect and/or in controlling the condition of the building structure.
Accordingly, the present invention provides cage structure comprising opposed side walls connected by opposed end walls defining a cage cavity therebetween, the cage structure being provided on at least one side or end wall with a façade spaced from said side or end wall to an extent sufficient to accommodate a surface effect material between the at least one side or end wall and the façade.
Preferably the façade comprises a material which permits viewing of the surface effect material when thus accommodated.
Also provided is a cage structure comprising opposed side walls connected by opposed end walls defining a cage cavity therebetween, the cage structure being provided on at least one side or end wall with an insert spaced from said side or end wall to an extent sufficient to accommodate a surface effect material between the at least one side or end wall and the insert. Preferably the side or end wall on which the insert is provided comprises a material which permits viewing of the surface effect material when thus accommodated.
The façade or insert may comprise a secondary cage structure comprising opposed side walls connected by opposed end walls defining a cage cavity therebetween.
The cage structure may be in the form of a multi-compartmental gabion comprising pivotally connected side and end walls and at least one pivotally connected partition wall, the at least one partition wall separating individual compartments of the gabion. In this case the façade or insert may comprise a secondary cage structure in the form of a multi-compartmental gabion comprising pivotally connected side and end walls and at least one pivotally connected partition wall, the at least one partition wall separating individual compartments of the gabion.
The cage structure may be provided with a first fill material filled against the façade or against the side or end wall on which the insert is provided, and a second fill material filled behind the first fill material, the second fill material being a different material from the first fill material.
The present invention also provides a cage structure comprising opposed side walls connected by opposed end walls defining a cage cavity therebetween, the cage structure being provided on at least one side or end wall with a façade spaced from said side or end wall to an extent sufficient to accommodate a surface effect material between the at least one side or end wall and the façade, the façade comprising a material which permits viewing of the surface effect material when thus accommodated.
Also according to the present invention there is provided a cage structure comprising opposed side walls connected by opposed end walls defining a cage cavity therebetween, the cage structure being provided on at least one side or end wall with an insert spaced from said side or end wall to an extent sufficient to accommodate a surface effect material between the at least one side or end wall and the insert, the side or end wall on which the insert is provided comprising a material which permits viewing of the surface effect material when thus accommodated.
It will therefore be seen that the invention permits the adaptation of a gabion structure to provide a surface effect by blocking or partially blocking through at least one side or end wall of the gabion viewing of a gabion fill material located in the gabion by interposing between the viewer and the gabion fill material a surface effect material accommodated either on the outside of the said side or end wall (and retained in place by the façade) or on the inside of the said side or end wall (and retained in place by the insert).
The façade may for example comprise a mesh material which permits viewing of the accommodated surface effect material through the mesh holes. Alternatively, the façade may comprise a transparent material—such as glass, acrylic or Perspex™ for example.
In the case of an insert, the side or end wall on which the insert is provided preferably comprises a mesh material which permits viewing of the accommodated surface effect material through the mesh holes.
If the surface effect material has a technical function rather than an aesthetic function, it is not necessary for the surface effect material to be viewable from the outside. Thus, if the surface effect material has anti-corrosive properties, for example, the façade or the side or end wall on which the insert is provided may be opaque
The façade or insert is preferably connected to the side or end wall on which it is provided, or may be connected either side of said side or end wall to neighbouring pairs of side, end walls. In the case of a multi-compartmental gabion, an insert may alternatively (or also) be connected to one or more partition walls neighbouring the side wall on which the insert is provided (partition walls in this case being the walls dividing compartments of a multi-compartmental gabion)
Such connection is preferably achieved by suitable mechanical means, for example one or more connectors, clips, ties or fasteners.
The connection, particularly in the case of a façade, may be removable. That is to say, the connector(s), clip(s) tie(s) or fastener(s) may be releasable or removable to allow detachment, or partial detachment, of the façade or insert. Such connection may be pivotal (one edge of the façade or insert being pivotally connected to a corresponding edge of the side or end wall, for example), or the façade or insert may be completely removeable from the side or end wall.
In accordance with the invention there is provided an apparatus for creating an outer surface of a structure wherein at least one wall of the structure defines a support surface, the apparatus comprising means defining a covering surface which overlies the support surface but is movable therefrom, so that a quantity of material to create the outer surface can be positioned between the support surface and the covering surface, and wherein the covering surface is in the form of a panel. When the surface effect material has an aesthetic quality. Typically the panel is a mesh panel or transparent panel through which the said surface effect material can be viewed.
In accordance with the invention there is provided an apparatus for creating an outer surface of a structure wherein at least one wall of the structure defines a support surface, the apparatus comprising means defining a covering surface which overlies the support surface but is movable therefrom, so that a quantity of material to create the outer surface can be positioned between the support surface and the covering surface, and wherein the covering surface is in the form of a panel. Typically the panel is a mesh panel or transparent panel through which the said surface affect material can be viewed.
Preferably, the support surface is defined by a mesh panel, and the edges of the cover panel are connected to the edges of the support mesh panel by means of suitable connectors. Suitable connectors may be in the form of elongated, coiled wire connectors threaded round the edges of the mesh panels at a pair of opposite edges of such panels, or threaded about intermediate spacing panels which serve to space the outer panels from the support of the structure.
Preferably, the structure is defined by a series of mesh panels, and the edges of the cover panel are connected to the edges of the support mesh panel by means of elongated, coiled wire connectors threaded round the edges of the mesh panels at a pair of opposite edges of such panels, or threaded about intermediate spacing panels which serve to space the outer panels from the support of the structure.
In one embodiment, the cover panels can be pivoted away from the support panel, or be removed therefrom to a sufficient extent to allow a cavity to be formed for the reception of the material to create the outer surface. The material can for example be a layer of turf or other horticultural vegetation, or decorative wood planks, board, or wooden fencing members (such as chestnut fencing poles), rocks, boulders, gravel to be placed on the support panel, or within the cavity. The cover panel can if required be positioned to retain the said material and again if required be connected, by re-threading the coiled wire connector through the edges of the cover and support panels, to trap the material in position between the panels.
The cover panel may be detached completely by removing both coiled wire connectors, or if the cover panel is mounted so as to lie spaced from the support panel to a sufficient extent, then the material may be positioned between the panels without removing the cover panel.
The support panel may be a wall panel of a collapsible structure as described above. Indeed, and as can be expected, all of the wall panels of one or both sides of such a structure may be provided with a surface effect as set for the above. The outer surfaces for the individual wall panels will usually be the same, but they could be different as desired. The invention also extends to a structure as described above, but wherein the various panels, or at least some of them are delivered to site, and the structure is erected on site by connecting the panels together, the outer surface being added after erection of the structure, or in an alternative arrangement, each support panel and its cover panel may be pre-connected and constructed to receive the material to form the outer surface therebetween.
Where the outer surface is created by growing material, this may eventually grow to such an extent as to conceal the cover panel mesh, and so using the collapsible structures mentioned above, could provide a quick means of erecting say a grassy bank, or a boundary hedge wall, which would have a natural look, without the need for any excavation. The invention therefore has considerable advantages. The invention may also have advantages in garden and landscape design, allowing the erection of structures having pleasing outer surface effects created with minimal use of an outer surface effect material.
A further advantage is that by selecting the appropriate material to form the outer surface, so heat insulation can be achieved by the said material thereby preventing adverse effects from the heat on the structure or the filling material or on other items adjacent the structure.
Typically, each or selected sides of the structure can be provided with the panels thereby allowing an outer surface to be created on all or selected sides of the structure. In addition, the material used to form the outer surface can also be positioned on the top of the structure to form an outer surface thereon.
In a further aspect of the invention there is provided a structure comprising a series of interconnected side panels forming a cavity for the reception of filling material therein to form a building structure having opposing side walls and end walls and wherein additional panels are provided along at least the side walls, externally thereof and joined to the same but spaced apart to form respective first and second cavities for the reception of material which differs to the filling material and form outer surfaces along at least the side walls.
In one embodiment the material used has better insulating characteristics than the filling material.
By way of explanation, an embodiment of the invention, with modifications, is illustrated in the accompanying diagrammatic drawings, and is explained in the description which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows in perspective view, a wall created by collapsible/erectable structures as described herein;
FIG. 2 is an exploded perspective view of the parts defining one cavity of one of the structures shown in FIG. 1 ;
FIG. 3 is an elevation view of one of the structures of FIG. 1 , to show how it can be folded to the collapsed position;
FIG. 4 is a perspective view of the wall of FIG. 1 , but showing the cover panels attached to form a structure according to the embodiment of the invention;
FIG. 5 is a view similar to FIG. 2 , but shows a modification;
FIG. 6 is a view similar to FIG. 4 , but showing the wall with the surface effect layers in position;
FIG. 7 is a view similar to FIG. 2 , but showing a further modification;
FIG. 8 is a cross sectional view taken on the line X-X in FIG. 6 , showing the support mesh, the cover mesh panel and the surface effect layer;
FIGS. 9 and 10 respectively are views to show two of the many different types of surface effect layer which can be used;
FIG. 11 is a plan view of a collapsible/erectable structure of a different type which can be used;
FIG. 12 is a plan of the structure shown in FIG. 11 , to illustrate how it can be folded to the collapsed condition;
FIG. 13A shows, in perspective view, a multi-compartmental cage structure with a façade; and
FIG. 13B shows, in perspective view, a multi-compartmental cage structure with an insert.
FIGS. 14A-B show coiled connectors attached to panels and moved sufficiently close so that the coils overlap and having a connecting rod inserted through the two coil connectors in views from the side (A) and top (B) of the structure.
DETAILED DESCRIPTION
Method to Execute the Invention
In FIG. 1 , a wall 10 is made up of three conventional collapsible/erectable structures of the type described herein and superimposed one upon the other as shown. The structures are illustrated by the reference numerals 12 , 14 and 16 . In this example the structures are of trapezoidal cross-section so that the bottom one 12 is the broadest, whilst the top one 16 is the narrowest. The structures are made up of panels as described, and these panels are interconnected by means of coiled wire connectors 18 , in known manner.
The structures 12 , 14 and 16 have no top or bottom, so that each defines a row of cavities 20 , 22 , 24 and so on, and the structures can be of any appropriate length. Typically, the structure may be of 10 cavity lengths but this is not to be considered as limiting.
In a practical example, the inner surfaces of the panels of the structures 12 , 14 and 16 are lined with a retaining material such as a geo-textile material so that when the structure cavities 20 , 22 and 24 are filled with appropriate filling material such as soil, sand, rocks or other ballast, that material will not pass through the meshes of the panels, it being remembered that the panels making up the structure will normally be of welded mesh construction.
These structures and the features described are of course already known.
FIG. 2 shows typically how the panels are used in each structure to form one cavity of the structure. In FIG. 2 the panels shown form the cavity 20 of the top structure 16 , and the panels comprise two similar mesh external side panels 26 and 28 formed from a regular grid of regularly spaced apart vertical bars and horizontal bars, including terminal top and bottom horizontal bars and terminal left and right vertical bars, the frame having an inner face and an outer face, and two end panels 30 and 32 , which comprise trapezoidal rod boundaries and intermediate parallel connecting rods, although this is still considered to be a mesh structure. Although shown in a trapezoidal form it should be appreciated that the structures can be cube or cuboid in shape, or any other suitable shape. The panels 26 to 32 are connected by means of the coiled wire connectors 18 , one of which is shown in greater detail in FIG. 2 , but each of the axes 18 A represents the position of one of these connectors. To connect the panels shown in FIG. 2 , they are brought into the trapezoidal configuration shown in FIG. 1 , and then the connectors 18 are spirally wound about the adjacent end bars of the panels so that each connector 18 embraces two bars of the respective adjacent panel edges. By this means, the panels are all pivotally connected together, and having regard to the diameter of the connector 18 , so there is a relatively free pivotal movement and there is a certain amount of clearance so, that the panel edges are free to move within the connectors. As shown in FIG. 2 , each connector 18 comprises at least two complete rotations of the coil, each rotation of the coil constituting a connecting means, the connector 18 therefore comprising at least two vertically spaced apart connecting means mounted on each of the left and right vertical bars so as to be disposed substantially coplanar with the frame, the connecting means being of substantially uniform length, the vertical spacing between each rotation of the coil being at least twice the length of the connecting means.
Of the panels 30 and 32 , if the panel 30 is at the end of a structure, it will be an end panel, but panel 32 will be common to the next cavity, and it is commonly known as a partition panel. The spiral connectors which connect panels 26 and 28 to panel 32 therefore also simultaneously embrace the next adjacent side panels of the next cavity, and so on.
It will be understood that the structures depicted in FIG. 1 is therefore foldable by relative pivoting between the various panels, and FIG. 3 is included to show how the structures can be folded. FIG. 3 shows the top structure 16 , and the additional panels making up cavity 22 are indicated by reference numerals 26 A, 28 A and 32 A. To collapse the structure the alternate partition panels 30 and 32 A are moved in opposite directions as indicated by the arrows 34 and 36 and so the whole structure can fold up zigzag or concertina fashion. Although the partition panels 32 and the end panels 30 are of trapezoidal form, there is sufficient clearance within the coil connectors 18 to allow complete folding to take place. Each of the structures 12 , 14 and 16 is collapsible in the same way, and therefore can be folded up for transportation purposes.
The structures 12 , 14 and 16 need not be of trapezoidal form, but this form is of particular advantage in relation to the utilisation of the present invention.
In the present invention, the outer surfaces of the panels of the structures shown in FIG. 1 are provided to receive material to form an outer surface to give the overall wall the appearance of having a surface of a material which is different from that which is typically placed in the cavity 20 , 22 , 24 . Referring to FIG. 4 , one embodiment is shown and in this embodiment, additional cover panels 40 to 50 are connected to the side panels of the structures as shown. These panels 40 to 50 are connected to the panels using the same connector coils 18 or in a modification, separate connector coils, and the coils connect so that the panels 40 to 50 are pivotable by virtue of being connected to these coils.
In order to provide the material to form the outer surface of the structure the panels 40 to 50 are pivoted clear of the side panels of the structures 12 , 14 and 16 , which side panels form support panels and the material can either be applied over the support panels as shown or placed into cavities defined between the support panels and cover panels. When the material is applied, the cover panels 40 to 50 are pivoted back onto the material, and are connected to each other by means of a coiled wire connector such as 18 at the free edges which are shown in FIG. 4 and which meet when the cover panels are placed into position. The coiled wire connectors which connect panels 40 and 46 , 42 and 48 , and 44 and 50 , may be coupled to the existing coiled wire connectors connecting the structure side panels by the insertion of a connecting rod through the two coiled connectors which are moved sufficiently close so that the coils overlap, thereby trapping the surface effect material which is viewable through the panels 40 to 50 as these panels also are of mesh construction. As shown in FIG. 14A in a side view and FIG. 14B in a view from the top, the connecting means 18 on the terminal left vertical bar is vertically indexed a predetermined distance, relative to the connecting means 18 on the terminal right vertical bar, so as to enable two such external panels to be disposed adjacent to one another. The connecting means 18 of one external panel 44 is interdigitated and vetically alligned with the connecting means 18 of the adjacent external panel 26 . Adjacent disposition of the panels enables a connecting rod or pin 19 to be passed through the interdigitated connecting means to releasably fasten the external panels to one another. The effect is in fact shown in FIG. 6 , where the dashed line areas are intended to represent material which in this embodiment is turf, so that the wall eventually will have a turf surface appearance. This is applied over the whole of the wall surface.
Instead of placing turf between the support and cover mesh panels, other suitable horticultural material can be used such as the material known as “seedam” which is a material which is supplied as a thin layer and in rolls, and is simply unrolled and placed on the ground. The layer comprises soil bound by means of a woven fabric, and the soil contains a seed material from which green vegetation grows.
FIG. 8 is included to show a section of this material, and in this figure the growing material is indicated at 52 as it grows through the cover panel 44 , and the support panel 26 is also illustrated. Between the support panel and the cover panel is the fabric 54 which forms the binding for the material, and also illustrated is the soil layer 56 . The Seedam material has roots which grow rearwards, and these are shown at 58 where they pass through the geo-textile material 60 on the inner side of support panel 26 .
The Seedam material is so constructed that the soil and binding fabric will retain moisture enabling the vegetation 52 to grow efficiently, but the addition of the geo-textile material 60 provides a further means for the retention of moisture, and the invention therefore is of particular relevance to the effective growing of the Seedam material. The Seedam material provides an excellent green covering and growth is limited as compared for example to grass so that cutting of the Seedam material is not necessary and therefore it is particularly suitable for this application.
Instead of the panels 40 to 50 being pivotally mounted as shown in FIG. 4 , they can be detachably mounted and the material for the outer surface can be mounted on the panels 40 to 50 and then the panels and the material applied as appropriate.
If reference is made to FIG. 5 , modifications are shown therein to the end panel 30 . At one side end panel is shown as having an extension wing 62 which forms a connecting bar for the coiled connectors. If the bar 62 is used for example for mounting the cover panels 40 to 50 , then these panels 40 to 50 will be spaced slightly further from the support panels of the structures so that thicker surface effect layers can be positioned between the panels. In this case the structure panel would be connected to rod portion 64 , and the cover panel would be connected to rod portion 62 .
Another modification shown in FIG. 5 is indicated that the opposite side of panel 30 and comprises an extension ladder 66 . One rail 68 of that ladder would be coupled to the end panel rod portion 70 by a coiled connector, whilst the other rail 72 serves for the mounting of the cover panel. If either of these modifications is adopted, it would be adopted on each of the end and partition panels of the foldable structure.
Another modification of this character is shown in FIG. 7 where the side panels 26 and 28 are replaced by a frame 74 , which serves to receive a mesh tray 76 . The tray 76 has a mesh base and rod extension sides 78 and 80 and a base extension 82 of the form shown. The structure is built using the side panels 74 , and when it is erected into a wall, the tray 76 is fitted for the receipt of the surface effect material which can be quite thick having regard to the height of the extensions 78 and 82 . After the tray is fitted, and the surface effect material is inserted, a cover panel such as 40 to 50 is applied over the tray to retain the surface effect material. All or one or more of the side panels of the structures 12 to 16 may be constructed in this way.
FIGS. 9 and 10 show how solid material may be used to form the outer surface and these are preferably used where the spacing between the support and cover panels is sufficient and these panels are held in spaced relationship.
In FIG. 9 it is shown that wooden planks 84 may be dropped in behind the cover panels or may be placed in the tray 76 of FIG. 7 , whilst FIG. 10 shows that chestnut-fencing posts 86 may be used for creating the surface effect. In another arrangement, the surface effect is created by one or more metal plates.
FIGS. 11 and 12 are included to show that collapsible/erectable structures in accordance with the invention may be of a different configuration from that shown in FIGS. 4 to 10 . In the arrangement of FIG. 11 , additional pivot connections are provided at 90 in each side of the structure. These pivot connections are parallel to the other pivot connections on that side of the structure and again is created by a coiled wire connector. Each side of each cavity therefore is split into two equal sections which can pivot relative to one another during the collapsing and erecting operations of the structure.
FIG. 12 shows how the structure can be collapsed by pivoting the side sections outwardly so that the partition panels 30 , 32 , 32 A and so on move together in the direction of the arrows 92 as shown in FIG. 12 . In this arrangement material can be placed into the cavities 93 when the structure is in the erected condition shown in FIG. 11 , with the material placed therein forming the outer surface of the structure on both elongate side walls of the structure. For example, if it is desired that the outer surface which is formed has insulating properties, and then material with such properties which are better than the material used to fill the main cavities 22 , 24 and so on can be used to fill the cavities 93 and hence provide the insulating outer surface. Such material could be rocks or the like and which therefore serve to insulate the structure as a whole. Furthermore, if required, the material used to form the outer surface of the elongate side walls can also be used to form the outer surfaces of the end walls of the structure in cavities formed therein, in the same manner by the addition of the panels and/or the top of the structure by placing and, if necessary, securing the insulating material in position, and even the base of the structure by placing said material onto the surface prior to placing the structure thereon and then filling the same.
Another modification shown in FIG. 13A provides a multi-compartmental cage structure 100 comprising opposed side walls 110 and 120 connected by opposed end walls 130 and 140 and at least one pivotally connected partition wall 150 . The at least one partition wall 150 separating individual compartments 160 of the cage 100 . The cage structure 100 further comprises a façade 200 in the form a secondary cage structure comprising opposed side walls 210 and 220 connected by opposed end walls 230 and 240 and at least one pivotally connected partition wall 250 . The façade 200 can accommodate a surface effect material 270 and comprises a material which permits viewing of the surface effect material when thus accommodated. Preferably, the end wall 230 of the façade 200 may define a cover panel that comprises a material which permits viewing of the surface effect material 270 .
In another modification shown in FIG. 13B , the cage structure 100 further comprises an insert 300 in the form a secondary cage structure comprising opposed side walls 310 and 320 connected by opposed end walls 330 and 340 and at least one pivotally connected partition wall 350 . The insert 300 can accommodate a surface effect material 370 and comprises a material which permits viewing of the surface effect material when thus accommodated. Preferably, the end wall 130 of the cage structure 100 and the end wall 330 of the insert 300 comprise a material which permits viewing of the surface effect material 370 .
A further possible embodiment of the invention may be contemplated in which the panels are provided with integrally formed limbs. Each limb may have a return that can engage a part of the gabion. In use, a layer of decorative material such as turf is interposed between the gabion and the panel. The panel is pressed against the gabion causing the decorative layer to compress. The limb bends to pass a wire of the gabion. Releasing the panel allows the decorative layer to expand back to its original dimension thereby causing the return of the limb to engage a wire of the gabion. Limbs can be provided instead of the aforementioned hinge-engaging fasteners or supplementary thereto. Additionally or alternatively, one or more limbs may be disposed towards the centre of each panel to inhibit bowing-out of the panel in use, which adverse effect may occur over time, e.g., as grass/vegetation root systems establish.
Method of Industrial Application of the Invention
In this invention it is not necessary that the structures are erected in the factory. They could be erected on site, where some or all of the pivot connections are made, and the surface effect material could be inserted in the erected structure on site or it could be supplied between the support and cover panels and supplied as panel units.
The invention provides a means of adding to the functionality and/or the aesthetic appeal of a gabion structure. Thus, if it is desired to provide a gabion structure with an exterior surface effect for aesthetic reasons, this can be achieved by using a surface effect material with aesthetic properties. Alternatively, if it is desired to provide a gabion structure with an improved functionality (e.g., resistance to weathering, corrosion, heat expansion, water penetration and the like) then a suitable functional material can be selected as the surface effect material.
The invention provides that an outer surface on the side walls of the structure can be created by using a covering mesh panel, where such effects either visual and/or protective would not normally exist. The invention has particular application to the collapsible type structures discussed herein, and can be used to maintain the characteristics of the same in extreme environmental conditions by preventing expansion or contraction and hence improving the safety of the structures as required.
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The present invention provides an apparatus for creating an outer surface effect of a structure wherein at least one wall of the structure defines a support surface, the apparatus comprising means defining a covering surface which overlies the support surface but is movable therefrom, so that a quantity of material to create the outer surface effect can be positioned between the support surface and the covering surface, and wherein the covering surface is in the form of a panel.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and apparatus for renewing an existing pipeline such as sewer pipeline and water supply pipeline without using any driving method and, more particularly, to an existing pipeline renewing method and an apparatus therefor, which renews an existing pipeline by breaking an existing pipe embedded in the ground so as to define the existing pipeline and by laying a new pipe therein.
2. Description of the Prior Art
Generally, deteriorated pipes embedded in the ground are renewed by a method which comprises the steps of excavating a ditch in a spot, under which the deteriorated pipe is embedded, by an open cut method or driving method to expose the existing pipe, removing the existing pipe, laying a new pipe therein, and subsequently refilling the excavated ditch.
This method, however, has to excavate the ditch. Therefore, when the spot to be excavated is on a road, the passage on the road has to be temporarily restricted.
Also, according to the prior method, since the use of the pipeline has to be stopped in the renewal, it is necessary to lay a bypass in place of the existing pipeline to be renewed.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method and an apparatus which can renew existing pipelines without using any open cut method.
Another object of the present invention is to provide an existing pipeline renewing method and an apparatus therefor, which can correctly lay new pipes without using any open cut method, even if the existing pipelines are curved.
Still another object of the present invention is to provide an existing pipeline renewing method and an apparatus therefor, which can discharge broken pieces of the existing pipes without using the existing pipe to be renewed.
A further object of the present invention is to provide a method and an apparatus, which can renew the existing pipeline without laying any bypass used for liquid flowing through the existing pipeline.
A still further object of the present invention is to provide a shield tunnelling machine, which can excavate existing pipes with small force without breaking the existing pipe at one time throughout a large extent of length.
The method for renewing existing pipeline according to the present invention comprises the steps of advancing a shield tunnelling machine from one end of an existing pipe defining the existing pipeline to the other end thereof, excavating at least the existing pipe by the shield tunnelling machine and disposing the new pipe in the excavated spot while the shield tunnelling machine is advanced.
The apparatus for renewing existing pipelines according to the present invention comprises a shield tunnelling machine for excavating an existing pipe embedded in the ground so as to define the existing pipeline and a means for disposing a new pipe in the excavated spot.
According to the present invention, since the new pipes are disposed while excavating the existing pipe by the shield tunnelling machine, it is not necessary to excavate the spot, in which the existing pipe is laid, by the open cut method.
In a preferred embodiment of the present invention, the shield tunnelling machine has a size larger than the diameter of the existing pipe. Therefore, this machine excavates not only the existing pipe but also earth and sand around the existing pipe. Thus, the machine will excavate an extent wider than the cross section of the existing pipe. Accordingly, the new pipe can be correctly laid by correctly advancing the machine even if the existing pipeline is curved.
In the preferred embodiment, the new pipe is forced into a vacant spot excavated by the machine with a thrust device provided with a plurality of jacks. Therefore, the new pipe is disposed in the excavated vacant spot and the machine is advanced by the thrust applied through the new pipe.
In the preferred embodiment of the present invention, the existing pipe is sealed by a seal device which is advanced along the existing pipe together with the machine. Further, the substance excavated by the machine is discharged from the machine by a discharging device. Thus, the excavated substance is prevented from flowing into unbroken existing pipes by the seal device, while the existing pipe and earth and sand therearound can be excavated. Therefore, the excavated substance does not enter the unbroken existing pipe. Accordingly, it is not necessary to install any apparatus for receiving the excavated substance in a shaft reached by the machine and then discharging the received substance from the shaft, thereby resulting in cost reduction. Further, the seal device can be connected to the machine by a connector.
In the preferred embodiment of the present invention, the broken pieces of the existing pipe due to the excavation are further broken into smaller pieces by a crusher disposed in a front region of the machine. The smaller pieces thus broken are discharged to the rear of the machine together with drain liquid supplied from the rear of the machine to the front region thereof. Accordingly, the discharging device is prevented from being clogged with the broken pieces of the existing pipe.
In the preferred embodiment of the present invention, while the machine is advanced, sewage flowing through the existing pipe is adapted to flow through the seal device and the machine by a temporary watercourse device. Thereby, since it is not necessary to stop the use of the pipeline to be renewed, the pipeline can be renewed without providing any bypass used for sewage.
The seal device and machine can be interconnected with each other by a connector having a watercourse used for sewage. In this case, the sewage is adapted to flow from the seal device to the machine through the watercourse of the connector.
The seal device is preferably provided with a main body extending axially of the existing pipe, a plurality of guides disposed at angular intervals around the main body and extending axially of the existing pipe and a sealing member disposed around the main body such that the sealing member is brought into contact with the inner surface of the existing pipe. Thus, even if the inner surface of the existing pipe is irregular, the movement of the seal device is not hindered by the irregularity.
Also, the seal device is further preferably provided with a tubular case disposed so as to extend axially of the existing pipe, a shaft rotatably inserted into the case, a mechanism for rotating the shaft, a plurality of guides disposed at angular intervals around the case and extending axially of the existing pipe and a sealing member disposed around the case such that the sealing member is brought into contact with the inner surface of the existing pipe.
The shield tunnelling machine in the preferred embodiment according to the present invention comprises a shield body, a partition wall for dividing the interior of the shield body into a front region and a rear region, a crankshaft rotatably journalled by the partition wall and having an eccentric portion disposed in the front region, a drive means for rotating the crankshaft, a cutter assembly having a plurality of cutter bits and disposed in the front region of the shield body, the cutter assembly being revolved or turned around the rotary axis of the crankshaft along with the rotation of the crankshaft while being rotated around the axis of the eccentric portion to excavate at least the existing pipe with the cutter and a means for discharging the substance excavated by the cutter assembly from the front region to the outside.
Each cutter bit is disposed so as to excavate the existing pipe when the cutter bit moves toward the rotary axis of the cutter assembly along with the turning and rotation of the cutter assembly. For example, each cutter bit may be disposed such that the cutting edge thereof is on the rotary center side of the cutter assembly.
According to the shield tunnelling machine comprising the cutter bits as noted above, since the existing pipe is subjected to breaking force when the cutter bits are moved to the rotary center of the cutter assembly, any crack extending longitudinally of the existing pipe is not liable to generate in the existing pipe, so that the existing pipe is not broken throughout a large extent of length. Also, since the existing pipe is subjected to force directing toward the center thereof, the existing pipe can be broken with relatively small force compared with the shield tunnelling machine for exerting force directing outward on the existing pipe.
In the preferred embodiment, the shield tunnelling machine further comprises a rotor rotatably journalled by the eccentric portion of the crankshaft and disposed in the front region of the shield body and a gear mechanism provided with an internal gear fixed to one of the shield body or partition wall and the rotor and an external gear fixed to the other. Further, the cutter assembly is mounted on the tip portion of the rotor. Thereby, the cutter assembly turns around the rotary axis of the crankshaft and rotates around the eccentric portion along with the rotation of the crankshaft.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects and features of the invention will become apparent from the following description of a preferred embodiment of the invention with reference to the accompanying drawings, in which:
FIG. 1 is a front view showing an embodiment of an existing pipeline renewing apparatus according to the present invention;
FIG. 2/is a sectional view of a shield body of a shield tunnelling machine for explaining the machine and a seal device;
FIG. 3 is an enlarged-scale sectional view showing an embodiment of the machine;
FIG. 4/is a sectional view taken along the line 4--4 in FIG. 3;
FIG. 5 is an enlarged-scale sectional view taken along the line 5--5 in FIG. 2;
FIG. 6 is an enlarged-scale sectional view taken along line 6--6 in FIG. 2;
FIG. 7 is an enlarged-scale sectional view showing an embodiment of the seal device;
FIG. 8 is a left side view showing the seal device shown in FIG. 7; and
FIG. 9 is a sectional view showing an embodiment of a connector.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An existing pipeline renewing apparatus 10 shown in FIG. 1 is used for work in which an existing concrete pipe 12 used for sewage embedded in the ground so as to define an existing pipeline is broken from its downstream side and a new concrete pipe 14 having a diameter larger than that of the existing pipe is laid.
The renewing apparatus 10 comprises a shield tunnelling machine 20 advanced from a starting shaft 18 constructed in a foundation 16 toward an arrival shaft (not shown) constructed on the upstream side thereof, a thrust device 22 for forcing the new pipe 14 into a vacant spot excavated by the machine 20 and advancing the machine 20, a seal device 24 movably disposed in the existing pipe 12 so as to prevent broken pieces of the existing pipe 12 and substance such as earth and sand excavated by the machine 20 from reaching the arrival shaft through the existing pipe 12, a discharging device 26 for discharging the excavated substance onto the ground and a temporary watercourse device 28 for permitting sewage in the existing pipe 12 to flow through the seal device 24 and machine 20 to a pipeline 30 on the downstream side.
The shield tunnelling machine 20 shown in FIGS. 2 to 6 comprises a tubular shield body 32 provided with first and second main bodies 34,36 which are butted against each other.
As shown in FIGS. 2 and 3, the first main body 34 is provided with a first tubular portion 34a defining a conical breaking chamber or a first space 38 having the bore gradually converging toward the rear, and a second tubular portion 34b defining a muddy water chamber or a second space 40 following the rear end of the first space 38 and having a cross-section larger than the rear end of the first space. The first and second tubular portions 34a,34b are mutually butted and removably coupled with each other at the rear end of the first tubular portion 34a and the front end of the second tubular portion 34b by means of a plurality of bolts. The first space 38 may have generally the same inner diameter as that of the second space 40.
As shown in FIG. 3, a second tubular portion 34b is formed on the outer peripheries of front and rear ends respectively with grooves extending circumferentially. On a flange formed at the outer periphery of the front end of the second tubular portion 34b by the groove formed on the front end of the second tubular portion 34b, there are disposed a plurality of bolts for removably interconnecting the first and second tubular portions 34a,34b. On the other hand, on a flange formed on the outer periphery of the rear end of the second tubular portion 34b by the groove at the rear end of the second tubular portion 34b, there are disposed a plurality of bolts for interconnecting removably the first and second main bodies 34,36.
As shown in FIGS. 3 and 4, an annular grating 42 directed inward and defining the first and second spaces 38,40 is mounted on the rear end face of the first tubular portion 34a. The grating 42 extends circularly along the rear end face of the first tubular portion 34a and is provided with a plurality of openings 44 spaced from each other at equal angular intervals around the axis of the shield body 32 such that small excavated substance is allowed to move from the first space 38 to the second space 40 while large excavated substance is prevented from moving from the first space 38 to the second space 40. The grating 42 may be mounted on the inside of the front end of the second tubular portion 34b. The second tubular portion 34b is provided with a partition wall 46 for dividing the interior of the shield body 32 into the front and rear regions.
As shown in FIGS. 3 and 4, the partition wall 46 unslidably and unrotatably supports a tubular sleeve 48 extending through the partition wall 46 axially of the shield body 32. To the side of the first tubular portion 34a of the partition wall 46 is fixed an internal gear 50 extending around the sleeve 48 by a plurality of bolts. In the sleeve 48, a crankshaft 52 extending through the sleeve 48 axially of the shield body 32 is rotatably journalled by a plurality of bearings 54. The crankshaft 52 is provided with a shaft portion 52a journalled by the sleeve 48 and an eccentric portion, i.e., a shaft portion 52b extending forward from the shaft portion 52a. The shaft portion 52a is coaxial with the shield body 32, while the axis of the shaft portion 52b is eccentric from the axes of the shield body 32 and shaft portion 52a by a distance e and disposed in the first space 38.
As shown in FIG. 3, in the shaft portion 52b, a rotor 56 constituting a crusher together with the first tubular portion 34a is rotatably supported by a plurality of bearings 58. The rotor 56 has a conical shape to have the outer surface gradually increasing toward the rear end side and is disposed in the first space 38. The gap between the outer surface of the rear end of the rotor 56 and the inner surface of the rear end of the first tubular portion 34a is set to be smaller than the dimension of each opening 44 of the grating 42 in the diametrical direction of the shield body 32. Further, a plurality of projections or grooves extending in the circumferential direction may be provided respectively on the inner surface of the first tubular portion 34a and the outer surface of the rotor 56, said surfaces defining the first space 38.
As shown in FIGS. 3 and 5, a cutter assembly 60 is fixed to the tip of the rotor 56 and provided with a plurality of arms 62 extending from the rotor 56 radially of the shield body 32 and a plurality of cutter bits 64 fixed to the respective arms 62. Each cutter bit disposed on the outermost end of each arm 62 has a cutting edge directed inward to the rotary center of the cutter assembly 60 and another cutting edge directed outward in the reverse direction, whereas the other cutter bits have cutting edges respectively directed inward to the rotary center of the cutter assembly 60 while the cutting edges are respectively disposed rearward from those of the cutter bits disposed at the outside of the other cutter bits noted above. Further, each cutter bit may be disposed to have the cutting edge located in an identical plane orthogonal to the rotary axis of the cutter assembly 60.
As shown in FIGS. 3 and 4, an external gear 66 meshing with the internal gear 50 is fixed to the rear end face of the rotor 56 by a plurality of bolts. The external gear 66 is eccentric from the internal gear 50 by a distance e which is identical with the eccentricity of the shaft portion 52b relative to the shaft portion 52a of the crankshaft 52. Thus, the gears 50,66 mesh with each other on one diametrical position which moves around the sleeve 48 along with the rotation of the crankshaft 52. As a result, the rotor 56 and cutter assembly 60 turn (revolve) around the axis of the shield body 32 while rotating (about their own axes) around the shaft portion 52b.
As shown in FIG. 3, a mechanical seal 68 is disposed between the rotor 56 and the internal gear 50 for liquid-tightly sealing between the rotor and the internal gear. The mechanical seal 68 is provided with an annular groove 70 provided at the rear end face of the rotor 56 and coaxial with the rotor 56, a tubular ring 72 fitted in the groove and having an approximately uniform outer diameter, an annular carrier seat 74 fixed to the front end face of the internal gear 50 and coaxial with the internal gear and a plurality of springs 76 for pressing the ring 72 against the carrier seat 74. The groove 70 opens to the side of the internal gear 50.
The ring 72 is provided with an annular main body slidably received in the groove 70 in the axial direction of the shield body 32 and a projection extending backward from the outer periphery of the rear end of the main body and coaxial with the main body. The main body and projection of the ring 72 have the same diameters and are placed coaxially with the rotor 56, i.e., eccentric from the internal gear 50 by the distance e. Each spring 76 is a compression coil spring disposed in a hole communicating to the groove 70.
The outer diameter of the main body and projection of the ring 72, more particularly the diameter of the contact surface (seal surface) between the rear end face of the ring 72 and the front end face of the carrier seat 74, i.e., between the ring 72 and the carrier seat 74 is smaller than the outer diameter of the carrier seat 74 by at least a distance 2e. Namely, assuming that the diameter of the outer periphery of the rear end face (projection) of the ring 72 is D 1 and the diameter of the outer periphery of the front end face of the carrier seat 74 is D 2 , the diameter of the contact surface (seal surface) between the ring 72 and the carrier seat 74 is represented by the following formula;
D.sub.1 ≦D.sub.2 -2e
As shown in FIG. 3, the partition wall 46 has an annular oil chamber 78 extending around the sleeve 48. Lubricant is received in the oil chamber 78. The oil chamber 78 communicates to a space defined between the crankshaft 52 and the sleeve 48 through a plurality of holes 80 bored in the partition wall 46, an annular groove 82 formed on the outer periphery of the sleeve 48 and a plurality of holes 84 bored in the sleeve 48. Thus, the space between the crankshaft 52 and the sleeve 48 and the gap between the partition wall 46 and the sleeve 48 are filled with the lubricant.
In the contact portion between the front end of the rotor 56 and the tip of the crankshaft 52, contact portion between the rotor 56 and the ring 72, contact portion between the partition wall 46 and the internal gear 50 and contact portion between the sleeve 48 and the partition wall 46, 0-rings for sealing are disposed respectively. Also, a seal material 86 for preventing the lubricant from overflow is disposed between the rear end of the sleeve 48 and the rear end of the crankshaft 52. The seal material 86 is fixed to the sleeve 48 by a plurality of bolts.
As shown in FIGS. 2 and 3, the second main body 36 is provided with the first tubular portion 36 a connected to the rear end of the second tubular portion 34b, the second tubular portion 36 b inserted into the rear end of the first tubular portion 36 a and a third tubular portion 36c connected to the rear end of the second tubular portion 36 b. A support wall 88 which is orthogonal to the axis of the shield body 32 is provided on the front end of the first tubular portion 36 a. A hole 90 for receiving the rear end of the sleeve 48 is bored in the support wall 88. The first and second tubular portions 36 a,36 b of the second main body 36 are interconnected with each other by a plurality of jacks 92 used for correcting the direction. Between the second tubular portion 36 b and the third tubular portion 36c and between the third tubular portion 36c and the foremost new pipe 14, connectors 93 and 95 are respectively disposed. A drive mechanism 94 for rotating the crankshaft 52 is fixed to the rear portion of the support wall 88 by a plurality of bolts. The drive mechanism 94 is provided with a motor and a reduction gear. The output shaft 96 of the drive mechanism 94 is inserted into a hole bored in the rear end of the crankshaft 52. The output shaft 96 is unrotatably coupled with the crankshaft 52 by a key 98.
As shown in FIG. 3, the crankshaft 52, sleeve 48 and partition wall 46 are formed respectively with watercourses 100,102 and 104 for guiding sewage in the existing pipe 12 to the temporary watercourse device 28. The watercourse 100 opens to the tip and outer periphery of the crankshaft 52. The watercourse 102 consists of an annular groove formed on the inner peripheral surface of the sleeve 48 and a hole for affording communication between the groove and the watercourse 104 so as to receive the sewage from the watercourse 100 and guide the same to the watercourse 104. On both sides of the annular groove, that is between the crankshaft 52 and the sleeve 48 annular mechanical seals 106 are disposed respectively for preventing the sewage from leakage. A pair of 0-rings are disposed between the sleeve 48 and the partition wall 46 to prevent the sewage from leaking through the connection of the watercourses 102,104.
As shown in FIGS. 3 and 5, on the outer conical surface of the rotor 56 are mounted a plurality of blades 108 which agitate excavated substance in the first space 38 along with the rotation of the rotor 56 to give fluidity to the excavated substance.
As shown in FIG. 1, the thrust device 22 is provided with a pair of rails 110 installed on the bottom of the shaft 18 so as to extend in the advancing direction of the machine 20, a slider 112 installed on the rail 110 so as to be movable along the rail and a plurality of jacks 114 for advancing the slider 112. The jacks 114 are mounted on a wall 116 constructed in the shaft 18.
The jacks 114 are extended after a new pipe is disposed between the preceding rearmost new pipe 14 and the slider 112. Thus, the slider 112 is advanced to force the new pipe 14 into the vacant spot excavated by the machine 20, thereby advancing the machine 20. When the jacks 114 are extended by a predetermined distance, the jacks 114 are then contracted and the slider 112 is drawn back. Subsequently, a new pipe is disposed between the slider 112 and the rearmost new pipe 14 and thereafter the jacks 114 are extended again. The operations of contracting the jacks 114 and drawing back the slider 112 to add the new pipe by disposing between the rearmost new pipe and the slider 112 are carried out a plurality of times until the renewal of the existing pipeline, which is embedded between the starting shaft and the arrival shaft for the machine 20, is completed.
As shown in FIGS. 7 and 8, the seal device 24 comprises a main body 120 movable in the existing pipe 12. The main body 120 is provided with a tubular shaft 122 extending along the axis of the existing pipe 12 and a tubular case or a frame 126 disposed around the shaft 122 such that the frame 126 is rotatable by a plurality of bearings 124. The shaft 122 is connected to the rotor 56 of the machine 20 by a connector 128 shown in FIGS. 1 and 9. A pair of mechanical seals 130 are disposed between the shaft 122 and the frame 126, and the lubricant is received in the region where the bearings 124 are disposed.
An agitating head 132 is fixed to the tip of the shaft 122. The agitating head 132 is provided with a boss 134 fixed to the shaft 122 and a plurality of blades 136 (six blades are shown, for example, in the drawing) fixed to the boss 134. The respective blades 136 are disposed at equal angular intervals about the axis of the shaft 122 and interconnected with each other on the tip of the shaft 122 by means of welding or the like.
On the tip of the frame 126 is mounted a guide head 138 for smoothing the movement of the seal device 24 in the existing pipe 12. The guide head 138 has a boss 140 mounted on the frame 126 by a plurality of bolts and a plurality of guides 142 (six guides are shown in the drawing, for example) fixed to the boss 140. On the outer periphery of the frame 126 are mounted a plurality of plate-like guides 144 (six guides are shown in the drawings, for example). The respective guides 142,144 extend axially of the shaft 122 and are disposed at equal angular intervals about the axis of the shaft 122. The respective tips of the guides 142 are interconnected with each other by means of welding or the like. The respective tips of the guides 144 are also interconnected with each other by means of welding or the like.
A tail cover 146 is mounted on the rear end of the frame 126 by a plurality of bolts, and a spacer 150 provided with a plurality of disk-like seal members 148 is mounted on the tail cover 146 by a plurality of bolts. Each seal member 148 is made of a material like elastically deformable rubber.
As shown in FIG. 9, the shaft 122 is connected to the connector 128 by a flange joint 152, while the connector 128 is connected to the rotor 56 by a universal joint 154 so as to allow the connector 128 and rotor 56 to be relatively bent. The universal joint 154 has a spherical body 156 provided in the connector 128, a pair of carrier seats 158,159 coupled with each other by a plurality of bolts to rotatably receive the spherical body 156 and a pin 160 for allowing the spherical body 156 to engage the carrier seat 158. The pin 160 extends through the carrier seat 158 so as to be received in a hole 162 bored in the spherical body 156. The hole 162 has the diameter larger than that of the pin 160. Therefore, the spherical body 156 and carrier seat 158 can bend within a predetermined extent of angle while being blocked from the relatively large rotation. The carrier seat 158 is fixed to the tip of the rotor 56 by a plurality of bolts.
When the rotor 56 of the machine 20 is rotated, the shaft 122 is rotated relative to the frame 126. When the rotor 56 is turned and the existing pipeline is curved, the seal device 24 is inclined to the machine 20, while the inclination is absorbed by the universal joint 154.
A hollow portion of the shaft 122 and that of the connector 128 constitute watercourses 164,166 for guiding the sewage in the existing pipe 12 to the watercourse 100 of the machine 20.
As shown in FIGS. 1 and 6, the discharging device 26 for excavated substance comprises a pipe 170 for supplying muddy water for draining muck to the second space 40 and a pipe 172 for draining the excavated substance together with muddy water from the second space 40. One end of the pipe 170 is connected to the support wall 88 by a connector 174 and communicates to the second space 40 through a watercourse 178 (see FIG. 3) provided so as to extend through the partition wall 46 axially of the shield body 32. One end of the pipe 172 is also connected to the support wall 88 by a connector 176 as shown in FIG. 6 and communicates to the second space 40 through a watercourse (not shown) provided so as to extend through the partition wall 46 axially of the shield body 32. The connectors 174,176 are fixed to the rear end face of the support wall 88 by a plurality of bolts (not shown).
As shown in FIG. 1, the pipe 170 communicates to a water supply tank 184 through a pipe 182, while the pipe 172 communicates to a sedimentation basin 188 through a pipe 186. A water supply pump 190 and a plurality of valves 192 are disposed in the pipe 182, and a drain pump 194 and a plurality of valves 196 are disposed in the pipe 186. The pipes 182,186 are provided on the way with bendable and expansible pipes. The cross section of each hollow portion of the pipes 172,186 for draining muck is larger than the area of each opening 44 in the grating 42. A discharge port of the water supply pump 190 and an intake port of the drain pump 194 are short-circuited by a short-circuit pipe 198 where a value 200 is disposed.
As shown in FIG. 3, on the bottom of the second space 40 is provided a partition 202 which prevents the muddy water supplied through the pipe 170 from reaching directly the pipe 172 and defines the muddy watercourse in the second space 40 such that the muddy water flows through the watercourse extending around the second space 40.
The pumps 190,194 are operated at the time of excavation by the machine 20. Thus, the discharging device 26 supplies the muddy water in the tank 184 to the second space 40 of the machine 20 through the pipes 182,170 and drains the muddy water in the second chamber 40 together with the excavated substance to the sedimentation basin 188 through the pipes 172,186. On the contrary, the pumps 190,194 are stopped at the time of the operation of adding the new pipes. After the pipes 182,186 are inserted into the new pipe under the state that predetermined valves are closed, the predetermined valves are opened to be operated the pumps 190,194. Further, a part of muddy water supplied to the second chamber 40 flows into the first chamber 38. However, most of the muddy water is drained to the sedimentation basin 188 by the discharging device 26.
As shown in FIGS. 1 to 3, the temporary watercourse device 28 is provided with a first guide 212 including a plurality of pipes interconnected with each other by a flange joint 210, an expansible and bendable second guide 214 connected to the rear end of the first guide 212, a drain pump 216 connected to the rear end of the second guide 214 and a third guide 218 for guiding the sewage drained from the drain pump 216 to the pipe line 30 provided on the downstream side. The tip of the first guide 212 is connected to the support wall 88 by a connector 220 (see FIG. 3) and communicates to the watercourse 104 of the machine 20. The first guide 212 has a valve 222 (see FIG. 2) at a portion located in the shield body 32. A valve 224 is also disposed in the third guide 218. One end of the third guide 218 at the opposite side to the drain pump 216 is inserted into the pipeline 30 together with a sealing member 226 disposed in the one end of the third guide 218.
When the pump 216 is operated, sewage in the existing pipe 12 is adapted forcibly to flow to the succeeding pipeline 30 through the watercourse 164 of the seal device 24, watercourse 166 of the connecting pipe 128, watercourses 100,102,104 of the machine 20 and respective guides 212,214,218. Further, when the new pipe is added, the pump 216 is temporarily stopped and the valve 222 is temporarily closed so that the second guide 214 is inserted into the new pipe.
In the renewing operation, the drive mechanism 94 of the machine 20 is operated to rotate the crankshaft 52. Thus, the rotor 56 and cutter assembly 60 are turned (revolve) around the crankshaft 52 in the same direction as the rotational direction of the crankshaft 52 and are rotated around the axis which is eccentric from the axis of the shield body 32 by a distance e. Since the position where the external gear 66 fixed to the rotor 56 meshes with the internal gear 50 fixed to the partition wall 46 is sequentially displaced along with the turning of the rotor 56, the rotor 56 and cutter assembly 60 are also rotated (about their own axes) around the shaft portion 52b in the opposite direction to the rotational direction of the crankshaft 52.
By the turning and rotating movements of the rotor 56 and cutter assembly 60, the cutter bits 64 not only turn and rotate together with the cutter assembly 60 relative to the shield body 32, but also move inward and outward relative to the center of the shield body 32, i.e., reciprocate radially of the shield body 32.
When the cutter assembly 60 is turned and rotated as mentioned above, thrust is given to the machine 20 through the new pipe 14 by the thrust device 22. Thus, the new pipe 14 is forced into an excavated hole, and the machine 20 breaks the existing pipe 12 with the cutter assembly 60. At the same time, the machine 20 is advanced while excavating the earth and sand around the existing pipe 12.
Since the cutting edge of each cutter bit 64 is directed inward and the cutter bit 64 reciprocates radially of the shield body 32, the cutter bit 64 breaks the existing pipe 12 and excavates the earth and sand around the existing pipe 12 when the cutter bit 64 moves toward the rotary axis relative to the shield body 32, i.e., moves inward. The existing pipe 12 will be broken by receiving inward force due to the cutter bit 64. As a result, the existing pipe 12 is broken with smaller force, compared with an apparatus for breaking the existing pipe 12 by exerting outward force, i.e., force for expanding the existing pipe 12. Also, since force for breaking the existing pipe does not act on the existing pipe 12 when the cutter bit 64 is moved outward, no large crack is generated longitudinally of unbroken existing pipe 12.
The broken pieces of the existing pipe thus broken and muck containing excavated earth and sand, i.e., excavated substance are received in the first space 38. The excavated substances thus received in the first space 38 are agitated by means of the blades 108 along with the rotation of the rotor 56 while moving from the first space 38 through the openings 44 in the grating 42 to the second space 40. The excavated substance reaching the second space 40 is mixed with muddy water supplied to the second space 40. The mixture, i.e., slurry is drained to the sedimentation basin 188 by the discharging device 26.
Large gravel and broken pieces contained in the excavated substance which is received in the first space 38 are pressed against the inner surface defining the first space 38 of the shield body 32 by the rotor 56 and then broken into smaller pieces capable of passing through the openings 44 along with the turning and rotating movements of the rotor 56. The broken smaller pieces capable of passing through the openings 44 are received in the second space 40 through the openings 44. Thus, the drain pipes 172,186 are not clogged with the gravel and broken pieces.
During the renewing operation, the first and second spaces 38,40 are held at a predetermined pressure for preventing the facing from collapsing and also for present the foundation from upheaving. Thus, a part of the excavated substance in the first space 38 flows into the existing pipe 12. However, the sealing member 148 of the seal device 24 is pressed against the inner peripheral surface of the existing pipe 12 by the excavated substance flowing into the existing pipe 12, so that the excavated substance is blocked from flowing in the existing pipe 12 forward further than the position of the seal device 24. The sealing member 148 blocks also the sewage in the existing pipe 12 from flowing into the first space 38.
The seal device 24 is advanced in the existing pipe 12 along with the advance of the machine 20. Then, since the guides 142,144 of the seal device 24 serve as sleds, the seal device 24 is moved smoothly even if the inner peripheral surface of the existing pipe 12 is irregular.
The shaft 122 of the seal device 24 is rotated around the axis of the shaft 122 along with the rotation of the rotor 56 of the machine 20. Thus, the sewage in the existing pipe 12 is agitated by the agitating blades 136, and solid substance in the sewage is crushed by the blades 136. As a result, the seal device 24 can be moved more smoothly and the watercourse of the temporary watercourse device 28 is never clogged.
The ring 72 of the mechanical seal 68 turns about the carrier seat 74 by the turning and rotating movements of the rotor 56 while being pressed against the carrier seat 74. However, force of the ring 72 drawn back against the force of the spring 76 due to the pressure in the second space 40 does not act on the rear end face of the ring 72. Namely, even if the ring 72 of the mechanical seal 68 is pressed against the carrier seat 74 by the turning and rotating movements of the rotor 56 while turning around the carrier seat 74, the whole rear end face of the ring 72 is always brought into contact with the front end face of the carrier seat 74 since the outer diameter of the ring 72 is generally uniform and the diameter of the contact surface (seal surface) between the ring 72 and the carrier seat 74 is determined by the following formula;
D.sub.1 ≦D.sub.2 -2e
Accordingly, the force caused by the pressure in the second space 40 does not act on the rear end face of the ring 72. Thus, it is possible to hold the liquid-tightness between the ring 72 and the carrier seat 74.
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A method for renewing an existing pipeline comprises the steps of advancing a shield tunnelling machine from one end of an existing pipe defining the existing pipeline to the other end thereof, excavating at least the existing pipe by the machine and disposing a new pipe in an excavated spot while the machine is advanced, whereby the existing pipeline is renewed by breaking the existing pipe embedded in the ground while laying the new pipe therein. An existing pipeline renewing apparatus embodying the method described above comprises a shield tunnelling machine for excavating an existing pipe embedded in the ground so as to define an existing pipeline and a means for disposing a new pipe in a spot excavated by the machine. Accordingly, since the new pipe is disposed while excavating the existing pipe by the shield tunnelling machine, it is not necessary to excavate the spot, in which the existing pipe to be renewed is laid, by an open cut method.
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BACKGROUND OF THE INVENTION
[0001] The invention pertains to a therapy system to deposit energy into a target zone.
[0002] Such a therapy system is known from the paper ‘Determination of the optimal delay between sonications during focused ultrasound surgery in rabbits by using MR imaging to monitor thermal build-up in vivo’ by N. J. McDannold et al. in Radiology 211(1999)419-426.
[0003] In this document an in vivo sonication experiment is mentioned in which a system for monitoring ablation of tissue is investigated. This known system monitors the ablation process in that heat damage to tissue in monitored. The known system for monitoring ablation performs monitoring e.g. on the basis of magnetic resonance images. Moreover, the cited document mentions that energy can be delivered as sonications in the form of focused ultrasound waves. Further it is mentioned that closely spaced sonications are delivered that are spaced by an intersonication delay to minimize thermal build-up. That is successive deposits of energy are separated in time by a cool-down period. To minimize this intersonication delay the temperature build-up should be measured during treatment. This temperature information is then used to control the intersonication delay.
[0004] The cool down period between successive deposits of energy allows temperature to reduce in a region around the focal region into which the energy is directly deposited. Thus, temperature build-up in the region around the focal region, i.e. the so-called off-focus temperature build-up, is reduced. Thus, the risk is reduced for thermal damage to healthy tissue outside of the focal region.
[0005] The therapy system is provided with a thermometry module to measure the temperature in a measurement field. Generally, the measurement field contains the focal region into which the energy is directly deposited. The duration of the cool down period between the successive deposits of energy is controlled on the basis of the measured temperature. In this way it is avoided that the time required for the successive deposits of energy is longer than necessary, while off-focus temperature build-up is avoided.
SUMMARY OF THE INVENTION
[0006] An object of the invention is to provide a therapy system which is able to more accurately apply energy into the target zone, in particular to more accurately set the cool down period.
[0007] This object is achieved by a therapy system according to the invention comprising a therapy module to perform successive deposits of energy in a target zone, the successive deposits being separated by a cool down period, the therapy system being provided with
a thermometry module to measure temperature in a measurement field and a control module to regulate cool down period in dependence of the measured off-focus maximum temperature during the energy deposit preceding the cool down period.
[0010] According to the invention, the cool-down period is set on the basis of the maximum temperature outside the focal region in the preceding energy deposit. This involves a relatively simple measurement of the maximum temperature. Because the duration of the cool-down period is more accurately set in order to initiate the next energy deposit as soon as temperature has sufficiently decreases so that the risk of off-focus temperature build-up is low.
[0011] In particular when MR thermometry is employed, a relative measurement of temperature of notably the target zone as well as off-focus region is obtained. That is, temperature is accurately obtained relative to a baseline value at the start of an individual energy deposition. As the cool down period between successive energy depositions has been accurately set already from the first energy deposition, reliable equal baseline temperatures apply for subsequent energy depositions.
[0012] One of the insights of the invention is that the temperature build-up of tissue outside of the focal region is dependent on the deposited energy density. Notably this is the case for energy deposition in the form of a focused ultrasound beam. The deposited energy density can be accurately calculated a priori and used to estimate the maximum temperature in the off-focus region. The maximum temperature in the off-focus region is approximately linearly dependent on the deposited energy density, i.e. the ultrasound energy density deposited in the off-focus region. The focal off-focus is formed by a cross-section transverse to the beam-path. The linear dependence appears to be valid when temperature decrease due to diffusion of heat can be neglected in the middle of the off-focus ultrasound cone during heating.
[0013] According to a further aspect of the invention a comparatively simple approximation of the duration of the cool-down period is proportional to the square of the maximum temperature the off-focus region reached in the preceding energy deposit. This dependency of the cool-down period on maximum temperature holds very well for when the cross-section of the beam-path of the energy deposit is circular (as for example if the beam-path has the shape of a cone). In other cases, the square relationship would be distorted slightly, but the exact relationship can be recalculated for any beam-path cross-section.
[0014] These and other aspects of the invention will be further elaborated with reference to the embodiments defined in the dependent Claims.
[0015] In a particular embodiment of the invention, the therapy module is a high-intensity focused ultrasound emitter. In this embodiment the energy deposit is carried-out by irradiating the target zone with a high-intensity focused ultrasound (HIFU) beam, often indicated as ‘sonication’. The HIFU-beam causes local heating of the tissue mainly in the focal region which causes thermal ablation in the focal region. Also slight heating of other regions within the HIFU beam occurs.
[0016] In another embodiment of the invention, the therapy module is a micro-wave emitter. In this embodiment the energy deposit is carried-out by irradiating the target zone with microwave irradiation. The microwave radiation causes local heating of the tissue which causes thermal ablation in the focal region, while also heating tissues in off-focus areas slightly.
[0017] In another embodiment of the invention, the therapy module is an RF-antenna. In this embodiment the energy is deposited via heat-conduction from the antenna placed in contact with the target zone. The RF-heating causes a local temperature increase which causes thermal ablation around the antenna, and by changing the energy density dependency on the maximum temperature rise all of the aspects outlined above may be employed.
[0018] In another embodiment of the invention, the monitoring module may rely on MRI, ultrasound or CT images for therapy monitoring. Any other temperature sensitive imaging modality may also be used.
[0019] The invention further relates to a computer program as defined in claim 3 . The computer program of the invention can be provided on a data carrier such as a CD-rom disk or a USB memory stick, or the computer program of the invention can be downloaded from a data network such as the world-wide web. When installed in the computer included in a therapy system the therapy system is enabled to operate according to the invention and achieve higher safety of use and more accurate setting of the cool down period.
[0020] These and other aspects of the invention will be elucidated with reference to the embodiments described hereinafter and with reference to the accompanying drawing wherein
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows a diagrammatic representation of the therapy system in which the invention is employed,
[0022] FIG. 2 shows an example of the cool-down time.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0023] FIG. 1 shows a diagrammatic representation of the therapy system in which the invention is employed. The therapy unit 1 , for example in the form of a high-intensity focused ultrasound (HIFU) unit generates a therapeutic action in the form of a focused ultrasound beam 11 . The focused ultrasound beam 11 is accurately directed onto a target zone 2 that includes the actual target 3 . For example the target is a tumor in (part of) an organ 2 of the patient to be treated. The HIFU unit 1 is operated so that the focused ultrasound beam 11 moves over the volume of the target zone 2 . The ultrasound beam 11 deposits energy in the target zone, causing elevated temperature especially in the tumor. In this way desired parts of the tissue is raised to a level where necrosis of the tissue occurs. Ultimately necrosis occurs in the tissue of the tumor and around it in the target zone once the desired thermal dose or temperature is reached. In particular the thermal dose can be calculated in a simple approximation as
[0000]
TD
=
∫
0
t
r
43
-
T
(
τ
)
τ
,
[0000] where r=0.25 when T<43° C. and r=0.5 when T>=43° C. A dose limit of 240 equivalent minutes at 43° C. is typically thought to result in necrosis. A modified version of the equation exists that takes the effect of uncertainty into account. In this scope one or several limits (or potentially a lower one) can be checked to ensure that once reached, deposition of energy is stopped. Following temperature only, tells us that necrosis will most probably occur, whereas thermal dose ensures us of it.
[0024] For example, necrosis is achieved when the intensity of at the focus of the focused ultrasound beam is about 1600 Wcm −2 for a duration of the order of tens of seconds. At this maximum energy level efficient necrosis is achieved without the risk of cavitation. The ultrasound beam can also be used to elevate tissue temperatures to non-necrosis temperature levels. These lower temperatures are useful in hyperthermia type applications.
[0025] The temperature distribution of the measurement field is derived from magnetic resonance signals. To this end the patient is placed in a magnetic resonance examination system (not shown) and magnetic resonance signals 22 are generated. The magnetic resonance signals are received by the MR signal acquisition system 21 that is part of the magnetic resonance examination system. The MR signal acquisition system includes RF receiving antennae (coils) and a signal processing system, such as a spectrometer. The acquired magnetic resonance signals are applied to the thermometry module 4 which derives the temperature distribution in the target zone. The phase of the magnetic resonance signals, but also other parameters, depends on temperature. The magnetic resonance signals are spatially encoded by means of encoding magnetic gradient fields, such as read and phase encoding gradients. The spatial resolution of the magnetic resonance signals and the ensuing temperature distribution is at the scale of a millimeter; even sub-millimeter resolution can be obtained where the smallest detail that can de distinguished has a size of a few tenths of a millimeter.
[0026] For example if there are several slices in the stack monitoring the temperature, then the measurement field used can advantageously be projected to all parallel slices in the focal-region even though the focal-point trajectory is only in the middle slice of the stack. Because the widest and hottest plane of the typically ellipsoidal heated region may wander towards the transducer during heating, this reduces the risk of the treated region having a larger radius than desired measured from the beam-axis. A measurement field along the beam-axis can also be applied to control that the 240EM dose length does not exceed a maximum length if we have a sagittal plane (which we do). This improves safety considerably.
[0027] Off-focus slices (e.g. two of them) can also be added at regions of particular interest, e.g. tissue interfaces where acoustic impedance changes significantly as such regions are prone to off-focus heating. These can be used to automatically detect excessive heating and/or thermal dose in these off-focus areas of interest for any single energy deposit and excessive cumulative heating and/or thermal dose for the entire treatment.
[0028] Accurate results in moving tissue are obtained when a motion correction is applied and phase contribution due to motion are separated from phase contributions due to temperature changes. The motion correction can be derived from the magnetic resonance signals, notably by redundant magnetic resonance signals from the central portion of k-space. A motion compensation module 23 is provided to derive the motion correction and apply motion compensation to the magnetic resonance signals. The motion corrected magnetic resonance signals are applied to the thermometry module 4 which derives local temperature distribution of the target zone 3 . Alternatively, the motion compensation module 23 can be configured or programmed in software to derive separate the contribution to the phase of magnetic resonance signals due to motion and compute the contribution of the phase due to temperature changes. The local temperature distribution is applied to the control module 5 , which controls the therapy module, i.e. the HIFU unit 1 to focus the focused ultrasound beam along a next trajectory. The centre of concentricity can for example be continuously evaluated (e.g. by Gaussian fits or weighted average) to take into account the possibility of the treated (notably heated) region shifting slightly (typically 1-2 voxels or 0.5-5 mm) during treatment due to e.g. spasms or slightly non-uniform heat diffusion.
[0029] The therapy system of the invention is provided with a delay module 6 which delays the activation of the therapy module 1 . The delay leads to the cool-down period. The delay is set by the control unit on the basis of the measured temperature. The delay unit may be configured to trigger the therapy module. In another embodiment the therapy module is configured to apply regular deposits of energy, e.g. apply regular ultrasound pulses (i.e.
[0030] sonications). In this embodiment the delay module is configured to interrupt the therapy module. In practice a number of sonications is interrupted or cancelled so as to cause the cool-down period.
[0031] FIG. 2 shows an example of the cool-down time to reach within 3° C. of the starting temperature as a function of the maximum near-field temperature. The fit is a square, i.e. quadratic function of the maximum temperature fitted through 3° C. and the R value is 0.90. In these cases the temperature was filtered with a 5×5 voxel median filter (voxel size 2.5×2.5 mm 2 ). Notably, spatial filtering of the measured temperature, e.g. by way of a median filter, improves the signal-to-noise ratio of the temperature measurement. The loss of spatial resolution does not lead to problems since the off-focus heating typically is void of sharp spatial gradients. This data was acquired for a HIFU-therapy module with a circular beam-path cross-section. The fit to 3° C. may be changed to any desired predefined baseline temperature level.
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A therapy system comprising a therapy module, e.g. a high-intensity- focused ultrasound transmitter, to perform successive deposits of energy in a target zone, the successive deposits being separated by a cool down period. The therapy system being provided with a thermometry module, e.g. by a magnetic resonance examination system configured for thermometry to measure temperature in a measurement field. A control module regulates the cool down period in dependence of the measured off-focus maximum temperature during the energy deposit preceding the cool down period.
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