description stringlengths 2.98k 3.35M | abstract stringlengths 94 10.6k | cpc int64 0 8 |
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BACKGROUND OF THE INVENTION
This invention relates to a novel elastomer and to waterless lithographic masters of the planographic type.
In conventional lithography, an aqueous fountain solution is employed to prevent the ink from wetting the nonimaged areas of the planographic plate. It has recently been discovered that the requirement for a fountain solution can be obviated by employing a planographic plate having a silicone, i.e. organopolysiloxane, elastomeric layer. Because the silicone is not wetted by the printing ink, no fountain solution is required. While the use of silicone elastomers as a printing surface has obviated the requirement for a fountain solution, it has been found that finely divided particulate material commonly referred to in the trade as "toner", is not easily attached to the silicone. Thus, the adhesive or nonadhesive property of the silicone which renders it useful for rejecting lithographic inks, also causes it to reject other materials such as toner. Accordingly, it has been difficult to prepare a printing master in which the toner could be sufficiently attached to the silicone such that it would not become removed after a short run on a printing press.
BRIEF DESCRIPTION OF THE INVENTION
It has now been discovered that conventional xerographic toner polymeric images can be chemically bonded to adhesive silicone polymer films by incorporating photo and/or thermally reactive azide pendant sites in said silicone polymer films which can be activated upon photo and/or thermal activation. The reactive azide (--RSO 2 --N 3 ) pendant site decomposes by a photo or a thermal excitation to form the highly reactive nitrene ##EQU1## which leads to crosslinking within the silicone polymer itself and insertion in the carbon-hydrogen bonds present in the toner polymer in contact with the silicone surface so as to bond the toner to said silicone surface.
These reactive silicone films are more strongly bonded to conventional substrates which is believed to be due to the highly reactive nitrene groups which are generated by the thermal and/or photo activation.
DETAILED DESCRIPTION OF THE INVENTION
Typical materials which include the types of master materials as well as instructions for preparing the masters are herein discussed in detail.
Substrates which can be employed for the printing master are those self-supporting materials to which the copolymer can adhere and be compatible therwith as well as possess sufficient heat and mechanical stability to permit use under widely varying conditions. Exemplary of suitable substrates are paper; metals such as aluminum; plastics such as polyesters, polycarbonates, polysulfones, nylons and polyurethanes.
When a substrate which is nonphotoconductive is employed, the substrate can be coated with a photoconductive material by conventional means such as draw bar coating, vacuum evaporation and the like. A thickness of between 0.02 and 20 microns is conventional. Typical inorganic crystalline photoconductors include cadmium sulfide, cadmium sulfoselenide, cadmium selenide, zinc sulfide, zinc oxide and mixtures thereof. Typical inorganic photoconductive materials include amorphous selenium, and selenium alloys such as selenium-tellurium, and selenium-arsenic. Selenium may also be used in its hexagonal crystlline form, commonly referred to as trigonal selenium. Typical organic photoconductors include phthalocyanine pigments such as the X-form of metal free phthalocyanine described in U.S. Pat. No. 3,357,989 to Byrne et al, and metal phthalocyanine pigments, such as copper phthalocyanine. Other typical organic photoconductors include poly(vinyl carbazole), trinitrofluorenone and photo-injecting pigments such as benzimidazole pigments, perylene pigments, quinacridone pigments, indigoid pigments and polynuclear quinones. Alternatively, the photoconductor can be dispersed in a binder of one of the aforesaid polymeric substrate materials to serve as the ink accepting substrate.
Silicone elastomers which can be employed are those which have reactive crosslinking sites and are capable of being cured to an ink releasing elastomeric condition. Exemplary of suitable silicone gums are those having only methyl containing groups in the polymer chain, such as poly(dimethylsiloxane); gums having both methyl and phenyl containing groups in the polymer chain, as well as gums having both methyl and vinyl groups, methyl and fluorine groups or methyl, phenyl and vinyl groups in the polymer chain with pendant hydroxyl or primary or secondary amino groups.
Azides which can be employed in the invention are those which are thermally and/or photo reactive to the silicone and preferably to the toner or thermoplastic organohydrocarbon imaging material. Further, the thermally reactive azides are stable at ambient temperature (20°-30° C). Exemplary of suitable azides are represented by the formula ##STR1## wherein R is chloro or hydroxyl, R' is chloro, cyano, hydrogen or nitro or an alkyl of from 1-8 carbon atoms and n is an integer of from 0-20.
A preferred azide is p-carboxybenzenesulfonyl azide. Only a minor amount need be employed to react with at least some of the pendant sites on the silicone. Preferably, enough azide is employed to react with all of the reactive sites on the silicone which generally comprise between about 0.1% and about 10.0% of the silicone. The silicone and azide can be reacted in a suitable solvent such as benzene, anhydrous ether and the like and agitated at room temperature for from 12 to 24 hours in accordance with the general procedure of Examples I and III.
To prepare a master, the reaction product in a suitable solvent can then be coated on the substrate by conventional means such as draw bar coating, and the solvent allowed to evaporate. The master can be imaged by conventional means such as electrostatographic imaging, either directly on the master and developed thereon, or formed and developed on a separate photoconductive surface and transferred to the master surface. The particulate imaging material can be any conventional ink accepting material commonly referred to in the art as toner. Typical toners include thermoplastic polymers such as polyethylene, polyesters and polymers of styrene. Typical polymers of styrene include polystyrene, styrene/n-butyl methacrylate copolymer and styrene-butadiene copolymer. Other materials which can be employed include: polypropylene, poly (α-methylstyrene), poly(hexamethylene sebacate), ethylene-vinyl acetate copolymers, polyamides, polyimides, phenoxies, polyesters and vinyls. After the master is imaged, the particulate material can be fixed by heating the master to soften the thermoplastic imaging material to cause the azido pendant sites on the silicone to become decomposed and lead to the formation of highly reactive nitrene species which by an insertion reaction strongly bond to the imaging material and the substrate. Typically, the imaging toners contain pigments and thus heat is a convenient means to bond the toner to the silicone and also crosslink the silicone. If a toner is used containing no pigment, then UV light can be employed.
The imaged printing master can then be employed on conventional planographic printing equipment by direct or offset means with the dampening system removed to provide good quality prints over an extended period of operation with conventional inks of the oleophilic, glycol or rubber based type.
The following examples will serve to illustrate the invention and embodiments thereof. All parts and percentages in said examples and elsewhere in the specification and claims are by weight unless otherwise specified.
EXAMPLE I
Into a 4 oz. round glass bottle is placed 50.0 grams of a 10 weight percent solution of Union Carbide Y-3557 silicone gum (containing 0.5 weight percent H 2 N(CH 2 ) 4 .CH 3 SiO) in benzene, 0.15 gram of p-carboxybenzenesulfonyl azide in tetrahydrofuran and 0.2 gram of 4A molecular sieve. The mixture was allowed to stand at room temperature for 24 hours and was found not reactive toward a polyisocyanate indicating the absence of free amino groups.
EXAMPLE II
The solution of Example I was draw bar coated onto a grained aluminum plate and allowed to air dry to a dry film thickness of about 3-4 microns. The plate was then exposed to an imaged mask for 5 minutes using a 10 watt UV lamp. Removal of the unexposed areas was obtained by washing with acetone to reveal the insoluble crosslinked silicone regions which had been exposed to the UV light. These crosslinked polymer areas were found to be tightly bonded to the aluminum substrate.
EXAMPLE III
The general procedure of Example I was repeated employing 10.0 grams of Union Carbide Y-3557 silicone gum in 200 cc. of anhydrous ether, 0.0955 gram of p-carboxybenzenesulfonyl azide and 0.0866 gram of dicyclohexylcarbodiimide. The mixture was stirred at room temperature for 12 hours and filtered. The reaction product as found not reactive towards a polyisocyanate, indicating the absence of free amino groups.
EXAMPLE IV
The solution of Example III was draw bar coated onto a gained aluminum plate and allowed to air dry to a dry film thickness of about 3-4 microns. The plate was then exposed to an imaged mask for 5 minutes using a 10 watt UV lamp. Removal of the unexposed areas was obtained by washing with acetone to reveal the insoluble crosslinked silicone regions which had been exposed to the UV light. These crosslinked polymer areas were found to be tightly bonded to the aluminum substrate.
EXAMPLES V-VI
The solutions of Examples I and III were each draw bar coated on an aluminum substrate by the procedure of Example II. The plates were placed in an air oven at 175° C for several minutes. The films were found to be highly crosslinked and firmly bonded to the substrate.
EXAMPLES VII-VIII
To the solutions of Examples I and III was added 5 weight percent benzophenone sensitizer. The exposure times were reduced to 30-60 seconds with the same results as said Examples II and IV.
EXAMPLES IX-X
The polymers of Examples I and III containing sulfonyl azide reactive pendant sites were each draw bar coated on aluminum plates from a 10 weight percent solution in benzene to a dry film thickness of about 3-4 microns. The films were allowed to dry for several hours at room temperature and a nonpigmented 2400 Xerox toner line copy image prepared and electrostatically transferred to the silicone surface. The dry toner image was fused by heating the plate at a temperature of 175° C for 5 seconds. The entire plate was then exposed to a 450 watt UV lamp for 8 minutes to crosslink the silicone film and chemically bond the toner image by means of the nitrene insertion reaction into the carbon-hydrogen bonds in the toner polymer. The silicone polymer was found to be crosslinked and firmly bonded to the aluminum substrate and the toner bonded to the silicone surface as indicated by its failure to be removed by the pulling action of Scotch tape. The plate was mounted on a Davidson Press operating in the direct mode with Ronico Rubber Base Lithographic Ink and high contrast copies obtained.
EXAMPLES XI-XII
The procedure of Examples IX and X were repeated but for the exception that a pigmented 2400 Xerox Toner was employed and the toner image bonded to the film and the film crosslinked by thermal exposure of the plates for five minutes at 175° C. Similar printing results were obtained.
EXAMPLE XIII
The previous examples are repeated employing polydimethylsiloxane elastomers with 0.1 and 10% pendant hydroxyl groups and with azides of the formula (supra) having chloro, nitro and cyano substituents and alkyl groups of from 10 and 20 carbons. Similar results are obtained.
Having described the present invention with reference to these specific embodiments, it is to be understood that numerous variations can be made without departing from the spirit of the invention and it is intended to encompass such reasonable variations or equivalents within its scope. | Waterless lithographic printing masters of improved contrast are provided by a coating suitable master substrate with a silicone elastomer gum having reactive pendant hydroxyl or amino groups, reacting a photo and/or thermally reactive azide with said pendant groups, depositing a particulate image pattern on said silicone comprising a thermoplastic organohydrocarbon polymer and crosslinking said silicone and chemically bonding said organohydrocarbon to said silicone to form a durable imaged waterless lithographic printing master. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to electric discharge machines (EDM) and more particularly to an electrode tube holding apparatus for an EDM.
2. Description of the Related Art
A general EDM works like that a rotatable chuck mounted to a spindle thereof holds and drives an electrode tube to rotate and eject high-pressure machining liquid and then electro-discharge machining is applied to a workpiece after the electrode tube is electrified, whereby a deep hole is formed in the workpiece for the machining purpose. Referring to FIGS. 1-2 , the electrode tube 1 of the conventional EDM is held at the rotatable chuck 2 and at a die guide 4 of a die guide holder 3 below the spindle 5 . As shown in FIG. 2 , while the electro-discharge machining proceeds, some deviations will occur between the axis of the rotatable chuck 2 and the axis of the electrode tube 1 and such deviations will result in deformation of the electrode tube 1 due to centrifugal effect while the electrode tube 1 is rotated. Although the electrode tube 1 is held by the die guide 4 , the length of the electrode tube 1 causes the centrifugal effect on itself to incur excursion of its distal end, which has become a serious problem. When such excursion is slight, some problems may happen, like deviation of the hole or enlarged diameter of the hole after machining. When such excursion is serious, it may even disable the EDM from normal operation. In this way, the conventional EDM is too unstable to apply the electro-discharge machining to the microminiature hole.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide an electrode tube holding apparatus for an EDM, wherein the electrode tube can avoid deformation.
The foregoing objective of the present invention is attained by the electrode tube holding apparatus. The EMD comprises a main body and a rise-and-fall member. The electrode tube holding apparatus comprises a gear wheel, a cantilever, and a rope. The gear wheel is pivotably attached to the rise-and-fall member and has a post. The gear wheel and the post can be rotated along with the movement of the rise-and-fall member. The cantilever is slidably mounted to the main body, having at least one guide hole running therethrough for inserting an electrode tube mounted to the rise-and-fall member. The rope has two ends connected with the cantilever and the post respectively. When the gear wheel is rotated, the post is rotated to wind or unwind the rope to further move the cantilever upward or downward; meanwhile, the cantilever is slidable along the main body and maintained within the midsection of the electrode tube.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of the conventional EDM.
FIG. 2 is a side view of the conventional EDM.
FIG. 3 is a front view of a preferred embodiment of the present invention.
FIG. 4 is a side view of the preferred embodiment of the present invention.
FIG. 5 is a schematic view of the preferred embodiment of the present invention in operation.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIGS. 3-5 , an electrode tube holding apparatus 60 for an EDM in accordance with a preferred embodiment of the present invention comprises a drive assembly 62 and a holding assembly 64 . The EDM comprises a base frame 20 , a spindle 40 , and an electrode tube 80 mounted to the spindle 40 .
The base frame 20 includes a main body 22 , a first motor 24 , a screw rod 26 , and a die guide holder 28 . The main body 22 is mounted upright to the EDM and movable along the vertical-axis or the horizontal-axis. The first motor 24 is fixed to a top end of the main body 22 . The screw rod 26 has a top end and a bottom end, the former of which is fixed to an output shaft of the first motor 24 via a coupling and the latter of which is rotatably attached to the main body 22 . The screw rod 26 can be driven by the first motor 24 to rotate clockwise or counterclockwise. The die guide holder 28 is fixed to a bottom side of the main body 22 , having a die guide 282 for inserting the electrode tube 80 therethrough for the electro-discharge machining.
The spindle 40 includes a rise-and-fall member 42 , a second motor 44 , and a chuck 46 . The rise-and-fall member 42 is mounted to the screw rod 26 for ascension and descension while the screw rod 26 is rotated. The second motor 44 is mounted to the rise-and-fall member 42 . The chuck 46 can be driven by the second motor 44 for holding the electrode tube 80 .
The holding apparatus 60 includes a drive assembly 62 and a holding assembly 64 . The drive assembly 62 has a gear rack 622 , a gear wheel 624 , a post 626 mounted to the gear wheel 624 , and a rope 628 . The gear rack 622 is fixed to a left side of the main body 22 . The gear wheel 624 is pivotably attached to the rise-and-fall member 42 and engaged with the gear rack 622 . The post 626 is rotated along with the gear wheel 624 . The rope 628 is a cable wire in this embodiment, having a top end and a bottom end, the former of which is fixedly connected with the post 626 and the latter of which is mounted to the holding assembly 64 . Along with the rotation of the post 626 , the rope 628 can be wound or unwound to further drive the holding assembly 64 . It is to be noted that the winding/unwinding direction of the rope 628 is converse to the upward/downward moving direction of the rise-and-fall member 42 . Namely, while the rope 628 is wound, the rise-and-fall member 42 is slidably moved downward The diameter of the post 626 is a half of that of the gear wheel 624 , such that the length for which the rope 628 is wound/unwound is a half of the distance for which the rise-and-fall member 42 is moved downward/upward.
The holding assembly 64 includes a guide rail 642 , a cantilever 644 , and two holding members 646 . The guide rail 642 is parallel to the gear rack 622 and fixed to a left side of the gear rack 622 . The cantilever 644 has a rear end slidably mounted to the guide rail 642 and fixed to a bottom end of the rope 628 for upward and downward sliding driven by the rope 628 . The cantilever 644 has at least one guide hole running therethrough for inserting the electrode tube 80 . Each of the holding members 646 has one end pivotably attached to a front end of the cantilever 644 for pivoting movement between a holding position and a retaining position on a pivot. While at the holding position, the holding member 646 holds the electrode tube. While at the retaining position, the electrode tube 80 is movable between the two holding members 646 for adjusting the electrode tube to a proper position before it is held.
When the EDM machines a workpiece, the workpiece is first fixed to a predetermined position under the spindle 40 ; meanwhile, each of the holding members 646 is at the retaining position, the electrode tube 80 is inserted through the holding member 646 and the die guide 282 , and then the holding member 646 is moved to the holding position. Next, the electrode tube 80 is electrified for discharge machining As shown in FIG. 5 , when the first motor 24 drives the screw rod 26 to rotate and the rise-and-fall member 42 descends, the bottom end of the electrode tube 80 approaches the workpiece to apply the discharge machining to the workpiece. Meanwhile, the gear wheel 624 pivotally attached to the rise-and-fall member 42 and engaged with the gear rack 622 is driven to rotate the post 626 in such a way that the distance for which the holding member 646 ascends is a half of the distance for which the rise-and-fall member 42 descends. In this way, the holding member 646 remains positioned at a midsection of the electrode tube 80 .
In conclusion, the present invention includes the following advantages.
1. Since the top end, the midsection, and the lower part of the electrode tube 80 are respectively held by the chuck 46 , the holding members 646 , and the die guide 282 , it can indeed reduce the deformation of the electrode tube 80 due to the deviation between the axis of the chuck 46 and the axis of the electrode tube 80 , thus preventing the machined hole from expanding. 2. The holding apparatus of the present invention can lessen the deformation of the electrode tube 80 , such that the electrode tube 80 remains straight to enable the discharge machining to meet the requirement for precision. Under the circumstances, the stability of overall discharge machining can be enhanced.
Although the present invention has been described with respect to a specific preferred embodiment thereof, it is in no way limited to the specifics of the illustrated structures but changes and modifications may be made within the scope of the appended claims. | An electrode tube holding apparatus is mounted to an electric discharge machine (EDM). The holding apparatus is slidable upward and downward along with the spindle of the EDM and maintained within the midsection of an electrode tube for reducing the deformation of the electrode tube during its movement. | 1 |
TECHNICAL FIELD
[0001] The present invention relates to a system for predicting a driver's intention to change lanes, and in particular to a system for predicting a driver's intention to change lanes that can be used for advanced driver assistance systems (ADAS).
BACKGROUND OF THE INVENTION
[0002] Continuous maneuver based advanced driver assistance systems (ADAS), such as a lane change assistance system (LCAS), assist the driver, for example, before and during lane changes. These systems have the risk to act as a nagging guardian for the driver as soon as there is a mismatch between the system support and the driver's intention, and this may unduly annoy the driver. For instance, the driver intends to follow the vehicle ahead on a motorway but LCAS may continuously recommend a lane change maneuver to the left adjacent lane by e.g. haptic, visual, acoustic or active longitudinal/lateral interventions, in order to overtake the vehicle in front. To solve this mismatch between the system and driver behavior the detection of the driver's intention is essential (e.g. left lane change, follow vehicle). This drastically reduces the paternalism of the driver and thus increases the driver's acceptance and the effectiveness of such a system.
[0003] Furthermore, to realize a LCAS that analyzes different lane change alternatives (as depicted in FIG. 1 ), and recommends the best gap (considering safety and comfort aspects) which is in line with the driver's lane change intention, an early driver intention recognition is indispensable.
[0004] DE 10 2006 043 149 A1 discloses an integrated transverse and longitudinal guidance assistant for motor vehicles, which has a trajectory calculating unit to calculate a lane change trajectory with a given distance of a vehicle traveling in front. The time to line crossing (TLC) is calculated so that the driver's intention to change lanes may be determined by detecting the driver steering toward the left or right line marker and the TLC being smaller than a certain threshold. However, as the driver's intention to change lanes is detected only after the lane changing maneuver is initiated, the detection of the driver's intention may be too late for most of the ADAS applications. Furthermore, it is necessary that the lane marker must be detected continually.
[0005] DE 10 2005 022 663 A1 discloses a vehicle driver assistance method that alerts the vehicle operator by using a voice output when the current lane ends and the vehicle is required to filter into the traffic of the adjacent lane. The lane filtering situation is detected if the lane on which the vehicle is traveling ends. The detection signal controls an acoustic indication such as a voice output and/or visual indicator. This patent document also discloses an apparatus for assisting the vehicle operator in filtering into the traffic of the adjacent lane. The disclosure is however limited to this scenario, and is not transferable to other scenarios.
[0006] U.S. Pat. No. 7,363,140 discloses a lane changing assistant for motor vehicles that assists the vehicle operator in finding an available window in the adjacent lane and computing an acceleration strategy adjusted to the window. The lane changing decision is left to the vehicle operator, and the system computes the acceleration strategy when the decision is an acceptable one.
[0007] US 2008/0201050 A1 is directed to a system for detecting gaps in an adjacent lane on a multi-lane road. The system provides a human machine interface (HMI) to assist a vehicle operator change lanes. The detection of the vehicle operator's intension is based on a set of driver reactions, such as activation of a turn indicator, and the acceleration and deceleration of the ego vehicle and the distance to the vehicle ahead. As the vehicle operator's intension is detected from the turn indicator and motion of the ego vehicle, the detection of the vehicle operator's intension is necessarily delayed.
[0008] The prior art thus fails to provide a system for predicting an intention of a vehicle driver to change lanes which is capable of an adequately early detection to be implemented as an effective part of a ADAS because the prediction is based on the detection of the initiation of a lane changing or overtaking maneuver. If the prediction is based on the detection of available gaps or windows in the adjacent lane, the prediction may be made earlier, but the availability of gaps may not necessarily means that the vehicle driver wishes to change lanes.
[0009] The prior art, even if it is configured to detect a driver's intention to change lanes, focuses only on one factor as a criterion that determines the intention of the driver to change lanes. In view of this limitation of the prior art, the inventors have realized that a vehicle driver snakes a lane changing or overtaking decision based on a number of factors (motivators and inhibitors), such as:
[0010] Slow vehicle driving ahead
[0011] Decelerating vehicles driving ahead
[0012] Faster vehicle approaching from behind
[0013] End of lane
[0014] Obligation to drive on left or right lane (depending on left- or right-hand-traffic)
[0015] Narrow lane (e.g. during road works)
[0016] Lane changes due to selected route (e.g. provided by navigation system).
[0017] Thus, there is a need to solve the problems described above, and provide an early and reliable driver intention ecognition or prediction which accounts for a plurality of reasons for lane change/overtaking maneuvers and decisions.
BRIEF SUMMARY OF THE INVENTION
[0018] In view of such problems of the prior art and the recognition by the inventors, a primary object of the present invention is to provide a system for predicting a driver's intention to change lanes which involves a minimum amount of time delay between the first occurrence of the driver's intention and the predicted intention.
[0019] A second object of the present invention is to provide a system for predicting a driver's intention to change lanes at a high accuracy.
[0020] According to the present invention, such objects can be at least partly accomplished by providing a system for predicting a driver's intention to change lanes, comprising: an ego vehicle sensor for detecting information on a motion of an ego vehicle; an environment sensor for detecting information on a motion of a vehicle traveling within a prescribed distance ahead of the vehicle in a same lane as the ego vehicle and/or on a motion of a vehicle traveling within a prescribed distance from the ego vehicle in an adjacent lane; a motivator computing unit for computing a motivator indicating a driver's intention to change lanes from the current lane to the adjacent lane according to outputs of the ego vehicle sensor and environment sensor; an inhibitor computing unit for computing an inhibitor indicating a driver's intention not to change lanes from the current lane to the adjacent lane according to the outputs of the ego vehicle sensor and environment sensor; and a prediction unit for predicting the driver's intention to change lanes by comparing outputs of the motivator computing unit and inhibitor computing unit. The environment sensor may comprise a radio wave, optical or acoustic radar.
[0021] The motivators and inhibitors may be determined from the speed of the traffic in particular the vehicle traveling ahead of the vehicle and the traffic in the adjacent lanes in relation to the traveling speed of the ego vehicle. The criteria for the motivators and inhibitors may be empirically or statistically determined, preferably by conducting a large number of tests on roads. As they can be determined before the vehicle operator starts a lane changing maneuver, the prediction made by the prediction unit may be used on a real time basis in a warning system or steering/acceleration assist system. By improving the accuracy of the motivators and inhibitors, the system is prevented from being excessively paternalistic.
[0022] A maneuver of the vehicle operator that is indicative of an intention to change lanes provides a relatively accurate prediction of the driver's intention to change lanes although the prediction may be too late for some purposes. Therefore, the prediction unit may be enabled to provide an improved prediction when an indicator indicative of a driver's intention to change lanes from the current lane to the adjacent lane from an output of the ego vehicle sensor is additionally taken into account.
[0023] According to a preferred embodiment of the present invention, the motivator computing unit is configured to determine if any of a plurality of motivator criteria are met, and the inhibitor computing unit is configured to determine if any of a plurality of inhibitor criteria are met, the prediction unit predicting the driver's intention to change lanes by comparing a weight of the motivator criteria that are met with a weight of the inhibitor criteria that are met.
[0024] The prediction unit may use a binary conjunction, a fuzzy logic conjunction or any other weight comparing algorithm in comparing the weight of the motivator criteria that are met with the weight of the inhibitor criteria that are met. The weight as used herein may include, not exclusively, the number of factors, a weighted total of the number of factors or any other quantitative measures of factors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Now the present invention is described in the following with reference to the appended drawings, in which:
[0026] FIGS. 1 a to 1 c are diagrams illustrating three different lane changing patterns;
[0027] FIG. 2 is a similar diagram illustrating two possible lane changing intensions:
[0028] FIG. 3 a is a block diagram of a system for predicting a driver's intention to change lanes embodying the present invention;
[0029] FIG. 3 b is a plan view showing ranges of onboard radars;
[0030] FIGS. 4 a and 4 b are diagrams illustrating parameter definitions for a lane change to a faster (left) lane;
[0031] FIGS. 5 a and 5 b are diagrams illustrating parameter definitions for a lane change to a slower (right) lane;
[0032] FIG. 6 is a flowchart illustrating a decision making process using a binary conjunction device;
[0033] FIG. 7 is a flowchart illustrating a decision making process using a fuzzy logic conjunction device;
[0034] FIGS. 8 a to 8 c show front and rear views as seen from an ego vehicle in three different lane changing scenarios; and
[0035] FIG. 9 is a graph illustrating how lane changing predictions are made by using the binary conjunction device and fuzzy logic conjunction device in the different scenarios.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] The system embodying the present invention and described in the following enables an early and reliable detection of the driver's lane change/overtaking intention in order to realize a maneuver based ADAS which supports the driver before and during lane changes. In addition, the system takes into account a plurality of different reasons or factors for lane change/overtaking maneuvers.
[0037] FIGS. 1 a to 1 c show different modes of lane changing maneuver. FIG. 1 a illustrates a case where an ego vehicle traveling in the current lane changes to the adjacent lane, typically because the other vehicle traveling ahead of the ego vehicle is slower. FIG. 1 b illustrates a case where the ego vehicle changes the current lane to the adjacent lane to filter into the traffic of the adjacent lane because the current lane is about to end. FIG. 1 c shows a case where the ego vehicle merges with the traffic of the adjacent slower lane, and then exits the slow lane to an exit road. In any of the situations, it is necessary that a window is available in the next lane for the ego vehicle to swing into, and the speed of the ego vehicle is adjusted to the speed of the traffic in the next lane.
[0038] In any of these situations, the vehicle operator has a choice to change the current lane to the right lane or to the left lane and to stay in the current lane as illustrated in FIG. 2 . The ego vehicle may travel at a speed chosen by the vehicle operator or at a same speed as that of the vehicle traveling ahead. The present invention may provide an assistance to the vehicle operator before and/or during lane change situations not only in lateral directions but also in longitudinal directions. By adjusting the speed of the ego vehicle, for instance, to that of the traffic in the adjacent lane, the window existing in the adjacent lane can be effectively utilized by the ego vehicle. In particular, according to a certain aspect of the present invention, the assistance to the vehicle operator is offered only when the vehicle operator's intention to change lanes and overtake the vehicle traveling ahead is predicted. Thereby, the system is prevented from being excessively paternalistic, and from annoying the vehicle operator. Also, the vehicle operator is prevented from being annoyed by warnings and urgings of the system to change lanes in case the vehicle operator has no intention to perform a lane changing/overtaking maneuver. Thus, the associated ADAS is made more acceptable to the vehicle operator, and more efficient in the operation thereof.
[0039] FIG. 3 a shows the structure of the invention. The vehicle V is equipped with a ego sensor unit 1 which is configured to detect dynamic variables of the vehicle V such as a traveling speed, a lateral speed, a yaw rate, a longitudinal acceleration, a lateral acceleration, etc., and an environmental sensor unit which may include a front radar 2 , a left radar 3 and a right radar 4 to detect not only the presence of other vehicles around the ego vehicle V but also the speeds of the other vehicles. The environmental sensor may additionally include a rear radar if the particular application requires one. FIG. 3 b shows the coverage of the three radars,
[0040] The outputs from these sensors are forwarded to a motivator computing unit 7 and an inhibitor computing unit 8 via an ego vehicle sensor interface 5 and environmental sensor interface 6 , respectively. The motivator computing unit 7 computes motivators that are expected to induce or otherwise cause the vehicle operator to change lanes, and the inhibitor computing unit 8 computes inhibitors that are expected to induce or otherwise cause the vehicle operator to keep the current lane, from the dynamic variables of the ego vehicle V detected by the ego sensor unit and the states of surrounding vehicles detected by the environmental sensor unit as will be described hereinafter.
[0041] The outputs of the motivator computing unit 7 and inhibitor computing unit 8 are forwarded to a prediction unit 9 which may consist of a binary conjunction device or a fuzzy logic conjunction device as will be described hereinafter. An output of the prediction unit 9 is forwarded to an output unit 10 that informs a linked ADAS the driver's lane change intention as soon as it is predicted. The output can be either two Boolean or two likelihood values indicating the driver's intention to change to the left or right adjacent lane. The system may optionally include an indicator computing unit 11 that detects the vehicle operator's intension to change lanes from the ego sensor unit 5 which may be configured to detect an activation of a turn signal and various dynamic variables (such as a steering angle, lateral and longitudinal accelerations and yaw rate) of the ego vehicle.
Parameter Definitions for Lane Changes to a Faster Left Lane
[0042] For the realization of a driver intention detection system that detects lane change intentions to a faster left lane, at least the following signal inputs are required (shown in Table 1).
[0000]
TABLE 1
signal
measured/
signal
unit
source
calculated
velocity
V ego
m/s
wheel speed
measured
sensors
distance
d front
m
front radar
measured
d front left
relative
V rel — front
m/s
front radar
measured
velocity
V rel front left
time gap
τ front
s
τ = d/V ego
τ front — left
time to
TTC front
s
TTC = d/V rel
collision
TTC front left
time of
t uninfluenced — front
s
front radar
calculated
uninfluenced
from τ
driving
and TTC
[0043] To improve the performance and reliability of the system, the following optional input signals may also be used.
[0000]
TABLE 2
signal
measured/
signal
unit
source
calculated
distance
d rear
m
front radar
measured
d rear left
relative
V rel — rear
m/s
front radar
measured
velocity
V rel — rear — left
relative
a rel front
m/s 2
front/rear
computed
acceleration
a rel front left
radar
from V rel
a rel — rear
a rel — rear — left
time gap
τ rear
s
τ = d/V ego
τ rear left
time to
TTC rear
s
TTC = d/v rel
collision
TTC rear left
average ego
v lane — ego
m/s
front radar
calculated from v rel
lane velocity
average left
v lane — left
m/s
front/rear
calculated
lane velocity
radar
from v rel of
left adjacent lane
driver's
v desired
m/s
ACC set-speed
ACC set-speed or
desired
or wheel speed
calculated from
velocity
sensors
average ego vehicle
speed
maximum
v ego — max
m/s
calibration
calculated from
velocity
parameters,
power, rolling
camera, map
resistance, mass,
data
drag coefficient,
velocity, traffic
sign recognition
maximum
a ego — max
m/s 2
calibration
calculated from
acceleration
parameters
power, rolling
resistance, mass,
drag coefficient,
velocity
left lane
p lane — left
n/a
camera or
calculated from
existence
radar
stationary radar
objects or camera
image
lane width
d lane — width
m
camera
calculated from
camera image
merging lane
p merge — lane
n/a
camera,
calculate of end
existence
map data
of lane from camera
image or exact map
data from navigation
system
no passing
p passing
n/a
camera,
traffic sign
signs
map data
recognition
Parameter Definitions for Lane Changes to a Slower Right Lane
[0044] For the realization of a driver intention detection system that detects lane change intentions to a slower right lane, at least the following signal inputs are required (shown in Table 3). These signals are additionally required to the signals described in connection with Table 1.
[0000] TABLE 3 signal measured/ signal unit source calculated average right v lane — right m/s front/rear calculated lane velocity radar from v rel of right adjacent lane time of t uninfluenced — right s front/rear calculated from uninfluenced radar right adjacent driving on gap size, position, right adjacent τ and TTC lane
To improve the performance and reliability of the system, the following optional input signals may also be used.
[0000]
TABLE 4
signal
measured/
signal
unit
source
calculated
distance
d rear right
m
rear radar
measured
relative
v rel — rear — right
m/s
rear radar
measured
velocity
time gap
τ rear — right
s
τ = d/V ego
time to
TTC rear — right
s
TTC = d/v rel
collision
speed limit
p speed — limit
n/a
camera, map data
traffic sign
sign
recognition
right lane
p lwane — right
n/a
camera or radar
calculated from
existence
sensor
stationary radar
objects or camera
image
[0045] The driver's intention is estimated based on three parameter sets as listed below. The conjunction device combines these parameters and determines the probability of a lane change/overtaking maneuver.
[0046] Motivators
[0047] Inhibitors
[0048] Indicators
[0049] Motivators increase the likelihood of the driver's lane change intention whereas inhibitors decrease the likelihood of the driver's lane change intention. The following measurable parameters are included:
[0050] The average velocity of a lane can be determined based on the traffic on these lanes. If the average velocity of the adjacent lane is greater than the average velocity of the current lane, the driver will intend to change to the faster lane.
[0051] If there is no vehicle on the right lane in case of right-hand-traffic, the probability of the driver's lane change intention will increase depending on the length of this section (obligation to drive on left or right side depending on left- or right-hand-traffic rules).
[0052] If the driver's desired velocity is greater than the current velocity, e.g. limited by a vehicle driving ahead, the driver will intend to change to the faster lane. If the current velocity is greater than the driver's desired velocity, the driver will intend to change to the slower lane. The desired velocity can be taken from the ACC set-speed directly or estimated by analyzing the driving profile for a certain period of time.
[0053] A short distance to a vehicle ahead increases the lane change probability.
[0054] A declining time-to-collision (TIC) indicates an increased lane change probability.
[0055] With an increasing predicted period of uninfluenced driving, without adjusting the velocity to the surrounding traffic, the lane change probability decreases, if the period of uninfluenced driving increases for the right lane, the probability to change to that lane will increase.
[0056] The type of vehicle directly influences the lane change probability. A vehicle with a low maximum velocity or power (e.g. truck or bus) increases the lane change probability.
[0057] Indicators are observable parameters of the driver behavior, mostly ego vehicle characteristics indicating that the driver has a strong intention to execute e.g. a lane change/overtaking maneuver, or to stay in the current lane. Indicators confirm the detected/estimated driver's lane change likelihood.
[0058] An analysis of the vehicle motion/trajectory within the own lane, e.g. expressed as the time-to-line-crossing (TLC), enables the short term detection of the driver's lane change intention.
[0059] A strong steering activity as well as a change of the relative yaw angle between the ego vehicle and the current lane trajectory indicates an imminent lane change/overtaking maneuver.
[0060] The left/right turn indicators indicate an imminent lane change/overtaking maneuver.
[0061] The motivators and inhibitors may be evaluated in various different manners. Typically, a measure or weight of the motivator or motivators is compared with that of the inhibitor or inhibitors, and a prediction may be made based upon this comparison. The following conjunction methods are possible candidates for performing this comparison:
Fuzzy Logic
Binary Conjunction
Neural Networks
Support Vector Machines
Markov Process
[0062] Bayesian Networks
State Machine
[0063] FIG. 6 shows a system using a binary conjunction in conjunction with an exemplary subset of input parameters. Thereby, the parameters like the driver's desired velocity, the ego velocity, the velocity of vehicle ahead, the velocity of vehicles driving on target lane, the acceleration ability and the time gap are considered. In case the inequality comparing the motivator with the inhibitor is true, a motivator criterion exists, and otherwise an inhibitor criterion exists. As soon as the difference between the number of motivator and inhibitor criteria exceeds a threshold X and an adjacent lane exists, the driver intents to change the lane.
[0064] Another approach to combine the parameters can be realized with the help of fuzzy logic. FIG. 7 shows a system using a fuzzy logic conjunction. Only the conjunction device has to be exchanged by the fuzzy logic conjunction in FIG. 6 . The pre-processing, motivator and inhibitor blocks are the same as used in the binary conjunction method.
[0065] Some exemplary fuzzy rules are described below:
[0066] If the differential velocity to a vehicle driving ahead is HIGH AND the driver's desired velocity is greater than the velocity of the vehicle ahead, the probability of the driver's lane change intention will be VERY HIGH.
[0067] If the accelerating ability is VERY SMALL the probability of the driver's lane change intention will be SMALL.
[0068] If the time gap to a vehicle driving ahead is VERY SMALL the probability of the driver's lane change intention will be HIGH.
[0069] If the ego vehicle's performance is HIGH AND a truck is driving ahead, the probability of the driver's lane change intention will be HIGH.
[0070] If the ego vehicle's width compared to the lane width is HIGH AND the adjacent lane with is greater than the current ones the probability of the driver's lane change intention will be HIGH.
[0071] To validate the driver's lane change intention detection methods two methods have been applied. The binary conjunction and the fuzzy logic conjunction method are realized in a simulation environment and additionally running in a real test car in real-time. First trials have been conducted on German Autobahn A3 between Frankfurt and Würzburg as depicted in FIG. 8 . The realized sensor setup allows a 360° environment sensing. However, for later series projects one front sensor like the already existing ACC/CMBS radar sensor mount on Honda Acura RL (tradename) and optionally two side sensors for the blind spot as used for e.g. for blind sport information systems (BSI) fulfill all requirements for both detection methods.
[0072] With the help of the test car more than 400 different lane changes have been recorded on different German motorways with 10 subject drivers. Each subject driver was asked to drive normally without any specific task. In this representative extraction the subject performed three lane changes (depicted in FIG. 9 ). The first two lane changes took place after approaching to a slower vehicle driving ahead in one's own lane (scenarios depicted in FIGS. 8 a and 8 b ). In the last scenario depicted in FIG. 5 c , the driver overtook a vehicle traveling immediately ahead of the ego vehicle after following it for a while. The results of the detected lane change intentions are described in detail in the following based on this representative extraction of the measured data.
[0073] The upper two graphs in FIG. 9 represent the results of the binary and the fuzzy logic conjunction methods and exemplary show some of the used input signals. The binary conjunction method's output signal could be either “0” or “1”. The output “0” means no left lane change intention detected, whereas the output “1” indicates a left lane change intention of the driver. The fuzzy logic conjunction method outputs a percentage value between 0 and 100%. The value indicates the probability of a left lane change. In the third graph from the top, the status of the left turn signal is shown. This signal is used as a baseline in order to compare and validate both methods and it is not an input signal of the lane change detection algorithms. The forth graph contains the relative velocity to the vehicle ahead and the bottom graph shows the corresponding time gap (τ=d/v ego ).
[0074] As depicted in scenario 1 in FIG. 8 a , the driver performed the first lane change after approaching a vehicle driving ahead. FIG. 9 shows the situation at 121 seconds. The driver's left lane change intention is detected by both algorithms approximately 2.3 seconds before the driver set the left turn signal. The intensity of the lane change intention increases with the reduction of the distance and thus a shorter time gap. The relative velocity of approximately 10 m/s is comparatively high. After starting the overtaking maneuver, the vehicle leaves the lane and a new object is selected by the radar sensor as the relevant vehicle in one's own lane. The intention recognition is set back to zero which indicates no lane change intention.
[0075] The situation before the second lane change is displayed in scenario 2 of FIG. 8 b and FIG. 9 at 167 seconds. Both algorithms detect the driver's left lane change intention 3 seconds before the turn signal had been activated by the driver. The situation is comparable with scenario 1 . The only difference is the distance between the ego vehicle and the vehicle ahead. The distance is greater and thus the time gap is longer compared to scenario 1 . For this reason the fuzzy logic conjunction algorithm detects a lower intention level of approximately ˜70%. Nevertheless, this value is still sufficient to indicate the left lane change intention. Shortly after the overtaking maneuver, the time gap changes quickly to a lower level because a faster vehicle on the new ego lane is detected as the new relevant vehicle by the radar sensors. Thus both conjunction algorithms returned back to zero which indicates no lane change intention.
[0076] Between 175 s and 207 s the driver is following the vehicle in front. The time gap in FIG. 9 is continuously on a low level of τ≈1.2 s. The driver has no urgent intention to perform a lane change in order to overtake the van. The fuzzy logic algorithm detects a low lane change intention ≦40% three times before the next lane change scenario at 207 s. These values are below the threshold of 50% and therefore no left lane change intention is given.
[0077] At 207 seconds, the driver started to consider overtaking the vehicle and thus changing to the left lane. The intention level of the fuzzy logic conjunction method increases. Two seconds later, at 209 seconds, the binary conjunction method detects the lane change intention, too. The descending slope of the fuzzy intention signal at 212 seconds and the fluctuating output signal of the binary intention algorithm occurred because the driver intended to change the lane but recognized a faster car approaching from behind (as depicted in FIG. 8 c scenario 3 ). The driver let the car pass before performing his left lane change/overtaking maneuver. The initial lane change intention has been recognized approximately 20 seconds before the driver set the left turn signal. This timing is sufficient to avoid a possible accident by a warning or an active intervention (e.g. braking, steering) in case the driver had not recognized the car in the rear.
[0078] Both methods, the binary and the fuzzy logic conjunction method, use state of the art input signals (e.g. radar data used by Honda's ACC/CMBS, wheel speed sensors, etc.) which are already available in today's vehicles, in order to detect the driver's lane change intention. The driver's intention is detected between 2.3 up to 20.0 seconds before the driver activates the turn signal. In contrast to state of the conventional algorithms, this invention enables an early detection of the driver's lane change intention even if the driver does not set the turn signal at all. Exactly this behavior is required to realize an advanced driver assist systems (ADAS) with an early intervention (e.g. warning, haptic feedback, braking or steering) in order to avoid critical lane change/overtaking scenarios in advance.
[0079] Although the present invention has been described in terms of preferred embodiments thereof, it is obvious to a person skilled in the art that various alterations and modifications are possible without departing from the scope of the present invention which is set forth in the appended claims.
[0080] The contents of the prior art references mentioned in this application are incorporated in this application by reference. | Provided is a system for predicting a driver's intention to change lanes at a high accuracy involving a minimum amount of time delay. A driver's intention to change lanes is predicted by a prediction unit ( 9 ) by comparing motivators and inhibitors ( 7, 8 ) which may be determined from the speed of the traffic in particular the vehicle traveling ahead of the vehicle and the traffic in the adjacent lanes in relation to the traveling speed of the ego vehicle by using an ego vehicle sensor ( 1 ) and an environmental sensor ( 3, 4, 5 ) that may comprise a radio wave, optical or acoustic radar. The criteria for the motivators and inhibitors may be empirically or statistically determined, preferably by conducting a large number of tests on roads. As they can be determined before the vehicle operator starts a lane changing maneuver, the prediction made by the prediction unit may be used on a real time basis in a warning system or steering/acceleration assist system. | 1 |
TECHNICAL FIELD
[0001] The present invention relates to a protective cover unit for a disc brake according to the preamble of claim 1 and a disc brake unit including such a protective cover unit.
STATE OF THE ART
[0002] Disc brakes for road vehicles, and particularly for heavy utility vehicles, suffer from considerable problems due to fouling of disc brake units by dust, water and waterborne pollutants which contaminate, when the vehicle is in motion, both disc brakes and brake yokes with brake linings. This can have consequences in terms of effects on moving parts. Dirt and corrosion may in particular lead to functional impairment causing uneven or impaired braking effect as between different disc brake units.
[0003] Moreover, differences in braking action and consequently uneven wear of brake linings may occur on the different sides of a disc if the linings are contaminated to different extents. All in all, in the state of the art, these problems reduce the usability of disc brakes and shorten service intervals, thereby increasing costs. This situation has also led to otherwise less efficient drum brakes being regarded as more reliable and as requiring less servicing.
[0004] Various attempts at alleviating the problems of disc brakes have resulted in shaft-mounted protection surrounding the brake disc, but this has entailed problems of impaired cooling, inherent oscillations and extra unsprung weight.
[0005] Brake yokes for disc brakes normally have an aperture for the extraction and insertion of brake linings and for inspection of the interior of the brake yoke. With a view to protecting the brake yoke's constituent parts and the brake disc against contamination via this aperture, it has been proposed to insert a protective plate which is integral with the lining holder. However, that solution has not entirely solved the problems of contamination via the extraction aperture, and such a protective plate is troublesome to fit and remove and has therefore hindered accessibility. The position of the protective plate within the aperture close to the brake linings is also regarded as hindering air flow and thereby reducing cooling.
OBJECTS AND MOST IMPORTANT CHARACTERISTICS OF THE INVENTION
[0006] One object of the present invention is to indicate a protective cover unit for a disc brake of the kind mentioned in the introduction, whereby the problems of the state of the art are reduced. A particular object is to propose a protective cover unit which functions better and is economic to manufacture and fit.
[0007] These objects are achieved in the case of a protective cover unit of the kind mentioned in the introduction by the features in the characterising part of claim 1 .
[0008] The result is a functional solution which is easy to fit to and remove from the lining holder. The fact that it abuts against an outer surface of the brake yoke prevents the formation of dust accumulation pockets which might entail risk of dirt being led into the aperture.
[0009] It should be noted that the space outside the brake yoke is very limited because of proximity to a wheel rim in cases where the brake unit is fitted adjacent to a wheel. However, a main cover according to the invention may, through its connection to the brake yoke, be made so thin and yet stable as not only to perform properly its protective function but also to be clear of a rotating wheel rim.
[0010] The invention results in reduced contamination in the region of the brake yoke and hence a more even braking action and more even lining wear, with the overall effects of greater functional reliability and longer service intervals for the brake disc units here concerned.
[0011] The main cover preferably provides protection for indicating cables from brake linings. In this respect it is of great advantage if the main cover is provided with lateral tabs which press these cables inwards towards the brake yoke, i.e. away from the region of a rotating wheel rim which might otherwise damage these cables.
[0012] In the case of a single-mounted wheel it is advantageous that the main cover be supplemented by an outer cover which reduces dirt ingress via the slits in the main cover.
[0013] Further advantages arise from further aspects of the invention which are indicated by the following detailed description of embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The attached drawings are as follows:
[0015] FIG. 1 depicts schematically a section through a vehicle wheel with a disc brake unit according to the invention,
[0016] FIG. 2 depicts parts of the disc brake unit in FIG. 1 in a partly dismantled perspective view,
[0017] FIG. 3 depicts a partly dismantled perspective view of an alternative embodiment of a disc brake unit according to the invention,
[0018] FIG. 4 depicts a plan view of a main cover,
[0019] FIG. 5 depicts a side view of the main cover in FIG. 4 and
[0020] FIG. 6 depicts a plan view of an outer cover.
DESCRIPTION OF EMBODIMENTS
[0021] FIG. 1 thus depicts in section a vehicle wheel with a disc brake unit 1 placed within the circumference of a wheel rim 3 which supports a vehicle tyre 2 . Broken lines at 4 represent a wheelshaft to which the vehicle wheel is fastened.
[0022] The disc brake unit 1 comprises a brake yoke 5 , a brake disc 6 fastened to the wheelshaft 4 , and brake linings 7 which are arranged on brake blocks and are for braking cooperation with the brake disc 6 . The brake yoke 5 comprises brake supports 8 (one depicted) for firm mounting of the brake yoke 5 . Each brake support 8 has its lower region lengthened so as to be designed to constitute a fastening point for a protective shield 9 which comprises a protective plate 10 and a fastening bracket portion 11 .
[0023] A main cover 17 forming part of a protective cover unit according to the invention is fastened to a lining holder 18 in the upper region of the brake yoke S.
[0024] FIG. 2 depicts in perspective the brake yoke 5 with its brake supports 8 , 8 ′, each of which is provided with a number of fastening holes 15 (shown in the brake support 8 ′) for accommodating fastening bolts for the brake yoke 5 . Ref. B denotes a brake disc
[0025] The outer extremity of the free end of each brake support 8 , 8 ′ is provided with a fastening eye 13 , 13 ′ with respective fastening holes 14 , 14 ′ for fastening screws 12 , 12 ′ intended to secure a unit comprising the protective plate 10 and fastening brackets 11 , 11 ′ by cooperation with holes provided in the free end portions of the fastening brackets 11 , 11 ′. The fastening brackets 11 , 11 ′ have a flat U-shaped cross-sectional profile and are curved so that they together substantially describe a circular arc which is at a substantially radially even distance from a wheelshaft when the brake shield is in position.
[0026] The contact surface between the protective plate 10 and the fastening brackets 11 , 11 ′ is substantially planar.
[0027] The radially innermost portion of the protective plate 10 is situated at a distance from the wheelshaft (ref. 4 in FIG. 1 ) such that a cooling air flow can pass through the resulting gap and proceed radially along the brake disc. The radially outer periphery of the protective plate 10 is drawn somewhat inwards towards the brake disc so as to create a somewhat enclosing structure.
[0028] The brake yoke 5 has in its upper portion an open recess 16 via which brake linings are intended to be extracted when they are being changed. The recess 16 is also used for other service operations relating to the disc brake unit, and for inspection purposes.
[0029] A lining holder 18 in the form of a supporting U-bolt is placed transversely across the recess so as to extend substantially parallel with the wheelshaft. According to the invention, this lining holder 18 is used for fixing a main cover 17 which is intended to provide dirt protection preventing the ingress of pollutants into the recess 16 . To this end, the main cover 17 substantially covers the adjacent outer arcuate section of the brake yoke.
[0030] The main cover comprises a thin sheetmetal structure designed to cover said recess. The fastening of the main cover is by fastening cooperation with the lining holder 18 whereby fastening screws 20 are inserted in countersunk recesses 19 with holes running through the main cover 17 and are screwed firmly into the lining holder 18 .
[0031] The main cover 17 is also provided with tabs 34 intended to cooperate with and protect indicating cables (see FIG. 5 ) for indicating the state of wear of the brake linings. These cables take the form of wiring routed from the respective brake linings to the vehicle's control system. This involves a cable from one of the brake linings being routed through a duct in the upper inner region 45 ( FIG. 2 ) of the lining holder and being thus protected from external effects of the main cover 17 .
[0032] A multiplicity of ventilation slits 33 are arranged in the main cover to allow flow of air which has been used for cooling and which emanates from the region of the disc brake during operation of the vehicle. Cooling of the brake unit is thus promoted despite the presence of the main cover.
[0033] FIG. 3 depicts another embodiment of the invention whereby fastening regions 23 distributed along the peripheral region of the protective plate 10 are used for fastening a protective housing 22 . The latter comprises a first portion 24 which runs substantially parallel with the protective plate 10 , and a second portion 25 which runs, in a manner surrounding the brake disc, substantially at right angles to the first portion 24 and the protective plate 10 . A structure enclosing both sides and the circumference of the brake disc is thus formed.
[0034] The fastening regions 23 are matched by corresponding portions of the protective housing 22 , and joining together is done, for example, by spot welding or by upset riveting.
[0035] Adding the protective housing 22 is applicable in the case of a single-mounted wheel, which means that the brake disc is protected from contamination in all directions, which is otherwise protected by the rim of a vehicle wheel.
[0036] In its upper region directed towards the brake yoke 5 , the protective housing 22 , as also the protective plate 10 , is adapted to connecting closely adjacent portions of the brake yoke 5 while leaving a gap for flow of cooling air towards an adjacent wheelshaft (not depicted).
[0037] At its upper portion, the brake disc unit in the case of a single-mounted wheel is supplemented by fitting an additional outer cover 26 outside the main cover 17 . This outer cover 26 is preferably at a substantially even distance from the main cover 17 so as to leave an air gap 27 between the main cover 17 and the outer cover 26 . To this end, the outer cover 26 has a number of spacing portions 35 which help to maintain the continuity of the air gap 27 . The spacing portions 35 also serve as regions for joining together the main cover and the outer cover, e.g. by upset riveting.
[0038] The object of the outer cover 26 is to protect the disc brake unit 1 from ingress of dirt, water etc. via the slits 33 in the main cover 17 (see FIG. 2 ). The fastening of the outer cover 26 to a main cover is advantageously effected by the same fastening screws as for the main cover 17 as individual parts of the lining holder 18 . Advantageously, both the main cover 17 and the outer cover 26 are manufactured as pressed sheetmetal parts.
[0039] FIG. 4 depicts the main cover 17 in a plan view in which the hatched regions 36 represent the areas where the main cover 17 abuts overlappingly against part of the arcuate, preferably cylindrical, outer surface of the brake yoke, which outer surface partly surrounds the aperture (ref. 16 in FIG. 2 ). Ref. 38 denotes a turned-down sidewall. Reinforcing grooves 39 and 40 are pressed into the main cover and run circumferentially relative to the disc brake unit.
[0040] FIG. 5 shows the function of the lateral tabs 34 . The routing of an indicating cable 41 from a brake lining is controlled by an inward pressure imparted to it by the lateral tab 34 . The cable is thus prevented from moving radially outwards to the region of a rotating wheel rim (represented by ref. 42 ) which might otherwise damage the cable.
[0041] FIG. 6 depicts the outer cover 26 with holes 44 running through it for fitting fastening screws into the main cover. Spacing and joining portions 35 are designed to cooperate with corresponding pressings 37 in the main cover (see FIG. 4 ) and to be used for joining these parts together, e.g. by upset riveting. A curved reinforcing groove 43 is pressed in the material.
[0042] The invention may be modified within the scopes of the ensuing claims whereby the constituent parts may be configured otherwise, e.g. so that there is greater or smaller overlapping of surfaces. The pressings may be configured otherwise, as also the provision of holes.
[0043] It is preferable that the protective shield and the protective cover unit be used in combination, but it is not excluded that either may be used without the other.
[0044] Applying the invention to a disc brake results in significant improvements as regards service life and function. It also results in more even brake lining wear and consequently longer service intervals between brake lining changes. | A protective cover unit including a main cover for partly covering an aperture for access to brake linings which is accommodated in a disc brake yoke for a disc brake. The main cover includes fastenings to a U-bolt-shaped lining holder which is connected to the brake yoke and runs transversely across the aperture. The main cover abuts against a portion of the brake yoke outer surface which at least partly surrounds the aperture. | 5 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent Application No. 60/874,916 filed Dec. 14, 2006 entitled “System and methods to facilitate the interaction between entities”, and application Ser. No. 12/001,847 filed Dec. 13, 2007, which are incorporated fully herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to facilitating private interactions, and more particularly to evaluating and presenting interactions between parties privately.
BACKGROUND OF THE INVENTION
[0003] Social and recreational clubs and private facilities may limit access to individuals who are members. Individuals may desire to experience other private clubs and facilities where they are not members, as well as meet other individuals. Members of clubs may also wish to invite guests to share in the enjoyment of clubs and facilities to which they members, as well as make new acquaintances.
[0004] Identifying individuals who are compatible with each other may be difficult and time consuming. Identifying other individuals that may have compatible interests may be socially awkward. In addition, providing personal information puts members at risk both physically and emotionally. Face-to-face meetings between individuals also inhibit meaningful feedback that may assist individuals in future interactions.
[0005] Accordingly, an efficient and effective apparatus, system and method is needed for assisting individuals in identifying possible compatible individuals without the need to divulge sensitive information or require prior personal contact. The systems and method may allow individuals to identify clubs and facilities of interest and share their experiences, or interaction at clubs and facilities. In addition, systems and methods may allow for feedback as well as allow other individuals to provide input in order to facilitate future interactions with compatible individuals.
SUMMARY OF THE INVENTION
[0006] It is, therefore, an objective of the present invention to provide devices, systems, and methods for facilitating interactions between individuals. The exemplary method may include providing information about a first facility by a member of the first facility and reviewing information about a second facility provided by a member of the second facility. The member of the first facility may request a meeting of the member of the second facility with details of the requested meeting. The requested meeting is transmitted to the member of the second facility. The member of the second facility may accept, deny, or modify the requested meeting. The response is transmitted back to the member of the first facility.
[0007] According to an exemplary embodiment of the present invention, the device may incorporate the following embodiments. In one embodiment, a member may put other members on their inclusive list or exclusive list. In another embodiment, members may rate the interaction and/or facility. In another embodiment, the first facility and second facility are private member only clubs or association. In yet another embodiment, the member of the first facility may be matched with the member of the second facility based exclusively on the membership of the facilities, time of the requested meeting, and members not being on an exclusive membership list. In another embodiment, the actions are carried out via a web portal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The above and other objectives and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference numbers refer to like parts throughout, and in which:
[0009] FIG. 1 is a flow chart illustrating a general overview of the interaction process between members according to a first exemplary embodiment of the present invention.
[0010] FIGS. 2A-C are flow charts illustrating a general overview of searching members for possible interactions according to a second exemplary embodiment of the present invention.
[0011] FIG. 3 is a flow chart illustrating a general overview of the exclusion of members according to a third exemplary embodiment of the present invention.
[0012] FIG. 4 is a flow chart illustrating a general overview of the inclusion of members according to a fourth exemplary embodiment of the present invention.
[0013] FIG. 5 is a flow chart illustrating a general overview of the matching of members according to a fifth exemplary embodiment of the present invention.
[0014] FIGS. 6A and 6B are flow charts illustrating a general overview of receiving a request and a response by a member according to a sixth exemplary embodiment of the present invention.
[0015] FIG. 7 is a flow chart illustrating a general overview of modifying the request according to a seventh exemplary embodiment of the present invention.
[0016] FIG. 8 is a flow chart illustrating a general overview of settling interaction costs between members according to an eighth exemplary embodiment of the present invention.
[0017] FIG. 9 is a flow chart illustrating a general overview of rating members according to a ninth exemplary embodiment of the present invention.
[0018] FIG. 10 is a exemplary diagram of components for processing interaction between members according to a tenth exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Each member may have several profiles, “reciprocation forms” and override tables which both facilitate the interaction of different parties and simultaneously safeguard each party's privacy. The methods and systems may be used to align people with the same demographics and characteristics. The methods and systems may be used to allow people to seek out others with the same demographics/characteristics privately. The tables in the database may include but are not limited to the following.
I. Member Profile
[0020] Contains information the member is willing to provide. Though some information may be required, more information may be voluntary. Each member may be informed that the more information they provide the better their chances of interaction may be.
II. Inclusive Preferences
[0021] The member indicates the traits of other members with whom he/she would most like to interact.
III. Exclusive Requirements
[0022] The member indicates the traits of other members with whom he/she would least like to interact.
IV. Inclusive Override Table (Friends List)
[0023] The member's list of other members from whom he/she will accept communications regardless of what is stated in II and III. (This list may grow over time as the members become more familiar with one another)
V. Exclusive Override Table (Not a Friend List)
[0024] The member's list of persons (other members) from whom he/she will not accept requests regardless of what is stated in II and III. (This may also grow over time as the members become more familiar with one another)
VI. Hosting Ratings
[0025] Each member has a rating table where other members they have hosted may rate them on a sliding scale and post comments.
VII. Guest Ratings
[0026] Each member has a rating table where other members of whom they have been a guest may rate them on a sliding scale and post comments.
VIII. Clubs and Facilities
[0027] Contains name, location, directions, ratings, scorecards, etc. for but not limited to restaurants, nightclubs, country clubs, yacht clubs, golf clubs, hunting clubs, fishing clubs, ski clubs, flying clubs, racing clubs and resorts. Facilities and clubs also includes organizations and private membership information about an individuals.
IX. Member Calendar
[0028] Contains information about events specific to the member and may also include general events. May or may not be accessed by other members. Member may allow partial or limited access.
[0029] Process
I. The member (“Initiating Member” or “IM”) initiates the process by making a request as shown in FIGS. 1-2 . This may be either a request for access to a club, facility, event, goods or services to be provided by another member or may be a like offer to another member. The request may comprise a pre-defined list of criteria or the member may specify criteria. Referring to FIGS. 3-4 , the member may also choose to use their inclusive or exclusive preference tables or create new ones for this request (they may be less picky when pressed for time or on a trip or have a specific agenda). II. The request is “sifted” through the member database and the other members' profiles and tables and delivered to those who remain after the search as shown in FIG. 5 . Attached to the request is the “public profile” of the member making the request or offer. This may include all or some of the required or voluntary profile information. III. The member who receives the request the “Responding Member” or “RM”) then has the following options as shown in FIGS. 6-7 :
A. Yes (response is sent back with RM public profile), RM member agrees to member's request/offer “as is”. Move to step IV. B. Yes, but with modifications (response is sent back with RM public profile), RM agrees to a member's request/offer, but with some modifications. The RM profile may then be exchanged with the Initiating Member making the request. C. No (system takes no action except to update the appropriate log files for this transaction), the IM may or may not receive any information that their request/offer was denied.
Each request may be considered OPEN for a period of time. After a specified period of time has passed the system may then takes steps to deliver an opportunity for the initiating member to make a match. These may include but are not limited to:
1. A message may be sent to the member offering other area clubs, facilities, events, goods or services that may be available. The message may contain links to the appropriate websites or additional information so the member can make an informed decision. 2. A list may be offered for each available club, facility, event, goods or services in the area, if the member would like the system to check availability, the member may indicate which they would like to pursue. The system or personnel may then contact each in an attempt to accommodate the member's request. 3. The system or personnel may attempt to contact the member to secure a club, facility, event, goods or services that fulfill the member's request.
D. Add to “Exclusive override table”, the IM is added to the RM's exclusive override table. The IM may not receive any information that their request/offer was denied.
IV. Initiating member receives positive responses.
At this point the two members are able to directly contact one another to iron out the details or if they prefer the system may facilitate the rest of the interaction.
V. Payment:
Members may be discouraged from seeking monetary remuneration exceeding the costs actually incurred by either party. If an exchange of funds is required for whatever reason the members may choose to handle it between themselves or may request that the system facilitate the process. Referring to FIG. 8 , the system may collect funds from the appropriate parties either directly or through a third party and release them or instruct a third party to release them based on agreed-upon criteria.
VI. Ratings
Referring to FIG. 9 , each of the participants may be asked to “rate” their experience. These ratings may include all aspects of their experience. Once completed these ratings may be publicly available to other members or viewable under certain circumstances. In order to prompt member participation a new request may require both members to rate their last experience, or some other form of enticement may be used. Each step of this process may be archived in the databases and available in case of member complaints, questions and/or for data mining in searches for trends and patterns in member behavior among other things.
[0048] Components
[0049] Architecturally, aspects of the invention can be located on a server, workstation, minicomputer, or mainframe as shown in FIG. 10 . A central server or group of servers may accomplish the processing and storage of data. Members may access the server and databases of information via networks, for example, the Internet. Members may log into the server from remote personal computers to receive and transmit data. Aspects of the system may be implemented at the server, member computer, or combination of both.
[0050] The systems and methods may be incorporated in software used with a computer or other suitable operating device. The software stored or loaded in the memory may include one or more separate programs, each of which comprises an ordered listing of executable instructions for implementing the methods and systems of the invention. The software may work in conjunction with an operating system and/or browser or email application. The operating system essentially controls the execution of the computer programs. The system and method may be implement by software stored within the memory of the computer running the operating system. The browser or email application controls the transmission and receive of information. The system or method may be implemented by an application executed by either a browser or email application or other remote application. For example, the system or method may also be implemented on a remote server that provides an email protocol that transmits information to and from user via email or website. The system and method may also include a Graphic User Interface (GUI) to allow the administrator or members to interact with the system.
[0051] Persons skilled in the art will appreciate that the present invention can be practiced by other than the described examples and embodiments, which are presented for purposes of illustration rather than of limitation and that the present invention is limited only by the claims that follow. | Devices, systems and methods for facilitating interactions between individuals are disclosed. The exemplary method may include providing member facility information and allowing other members to review the facility information. Members may request a meeting with another member with details of the requested meeting via the system. The request is transmitted to another member and the other member may accept, deny, or modify the request by the other member. Members may have an other members inclusive list or other members exclusive list to assist in facilitating interactions. Ratings may be used to rate other members and interaction facilities to aid in facilitating future interactions. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to liver parenchymal cells having a clonal growth ability, a method for obtaining such cells, a method for subculturing such cells, and a subculturing system of primary hepatocytes. More particularly, the present invention relates to progenitor cells culturing system of liver parenchymal cells which are useful as a material for cell biological and molecular biological research on development, differentiation and proliferation process of hepatocytes or on the carcinogenic mechanism thereof, or as medical materials for developing therapeutic techniques of various hepatic diseases.
2. Description of Related Art
An animal is a multicellular organism formed through repeated division of a fertilized egg and differentiation thereof into various structures (cell aggregates) taking charge of different functions. The individual structures composing a body of organism maintain the individual by producing cells having active differentiation ability through constant division and growth of individual cells. Therefore, in order to understand the biological facts of humans and other animals or to develop a therapeutic technique through clarification of the carcinogenic mechanism, it is believed important to analyze in detail cells composing individual structures to clarify the developing and differentiating process and the mechanism of proliferation.
A method has conventionally been established, as a means to analyze in detail cells of structures in vivo, to culture cells taken out in vitro, and causing division and growth of cultured cells to ensure survival through subcultures. While various methods of subculturing primary hepatocytes have been studied, the only actual case of subculture of primary hepatocytes so far reported is one for calf, and no case has yet been achieved as to rat and mouse. A reason is that, because hepatocytes are cultured in a serum-free medium added with various growth factors on a collagen-coated dish effective for adhesion and growth of hepatocytes, it is difficult to detach the cultured cells from the dish with a little damage, and hepatocytes treated with an enzyme such as trypsin have very serious damage. While hepatocytes cultured with a dish not coated with collagen coat and a serum-free medium can be detached with a slight damage, those cultured cells cannot continue to live or grow for a long period of time, although it may be possible to adhere them again onto the dish.
More recently, on the other hand, it has been reported that small hepatocytes growing while forming a colony appear in a culture system comprising a medium added with nicotinamide and epidermal growth factor (EGF). These small hepatocytes are confirmed to express functions of matured hepatocytes such as albumin, to be divided 2 to 3 times during the first four days, and to be partially present on the 20th day of culture in the form of cells having a growth ability. Since the colony forming frequency in such a culture system is high for hepatocytes isolated from an young rat and decreases according as the age in weeks increases, these subcultured hepatocytes are considered to be "committed progenitor cells".
In this case also, however, subculturing of cells is not satisfactory, leaving problems to be solved regarding prevention of damage. It is therefore the current situation the subculturing of hepatocytes has not as yet been established.
Furthermore, in order to understand complicated and diverse functions of hepatocytes or clarify carcinogenic mechanism thereof, it is considered essential to identify pure precursor hepatocytes (progenitor cells) for which orientation of differentiation has not yet been specified, but presence thereof has not yet been confirmed or a preferential culturing method has not been established.
For these progenitor cells, the following facts are conventionally known and the following efforts to identify them are reported. More specifically, it is reported that stem cells are developed from the foregut endoderm in the course of liver development, and these stem cells differentiate into hepatocytes and bile duct epidermal cells (Shiojiri, et al.; Cancer Research. Vol. 51, pp. 2611-2620, 1991). While there is no case of confirmation of stem cells in liver of an adult (such as rat), oval cells emerging in a precancerous state in the course toward cancer of rat can lead to either hepatocelluler carcinoma or cholangiocarcinoma. This oval cell is therefore attributable to an aberrant differentiation of stem cells present in the liver of the adult rat. Hixon, et al.(Pathobiology, Vol. 58, pp. 65-77, 1990) prepared several antibodies against surface antigens of oval cells obtained from experimental hepatocarcinogenesis. Brill, at al.(Proc. Soc. Exp. Bio. MEd., Vol. 204, pp. 261-269, 1993) selected cells conbined with these antibodies from among hepatocytes of an adult rat by means of a sorter to investigate properties of these cells. As a result, it was suggested that these cells contained hepatic progenitor cells among those combined with antibodies against surface antigens of oval cells, since cells growing and differentiating into matured hepatic cells by culturing in a medium added with additive factors, or culturing on a feeder layer of mesenchyme cells of a fetus.
Presence of hepatic progenitor cells is estimated by several pieces of evidence, but has not as yet been confirmed.
SUMMARY OF THE INVENTION
The present invention has an object to provide liver parenchymal cells having a clonal growth ability considered to contain hepatic progenitor cells. Another object of the present invention is to provide a method for obtaining such cells and a method for subculturing such cells.
Further another object of the present invention is to provide subculturing systems which permit subculturing of primary hepatocytes while growing and surviving for a long period of time.
The present invention provides liver parenchymal cells having a clonal growth ability, which possesses at least one of the cell biological properties such as:
(1) presence of peroxyzome;
(2) being positive to hepatocyte-markers;
(3) being partially positive to neoplastic hepatocyte-markers or immature hepatocyte-markers;
(4) being positive to antibodies against the surface antigens of oval cels; and
(5) being partially positive to bile duct cell-markers.
The present invention provides also a method for obtaining liver parenchymal cells having a clonal growth ability, which comprises: isolating hepatic cells from liver of an adult mammal; centrifuging the hepatic cells with low speed into heavy and light fractions; and culturing small cells in the light fraction on culture medium necessary containing fetal bovine serum and ascorbic acid whereby liver parenchymal cells belonging to the small cells from a colony.
In addition, the present invention provides a method for subculturing liver parenchymel cells having a clonal growth ability, which comprises: isolating hepatic cells from liver of an adult mammal; centrifuging the hepatic cells with low speed into heavy and light fractions; culturing small cells in the light fraction on a dish with culture medium necessary containing fetal bovine serum and ascorbic acid whereby liver parenchymal cells belonging to the small cells form a colony; detaching the cells of colony from the dish with a solution of EDTA; and re-culturing the detached cells on the same medium.
Moreover, the present invention provides a subculturing system for primary hepatocytes detached from a dish with a solution of EDTA, of which medium contains nicotinamide and ascorbic acid.
In accordance with the present inventions there are provided liver parenchymal cells having a clonal growth ability considered to contain hepatic progenitor cells, a method for obtaining such cells and a method for subculturing such cells. It is accordingly possible to research in detail the process of development and differentiation of hepatic cells and the mechanisms of growth and expression of functions, and to open up a new way to clarification of mechanisms of hepatoma and various other human hepatic diseases and development of therapeutic methods against these diseases.
The present invention permits subculturing of primary hepatocytes.
BRIEF DESCRIPTION OF THE DRAWINGS
The file of this patent contains at least one color photograph. Copies of this patent with color photograph(s) will be provided by the Patent and Trademark Office upon request and payment of the necessary fee.
FIGS. 1(a), (b), (c) and (d) are phase contrast micrographs (29.4 magnification) illustrating examples of culture of first subculture on the second, the fifth, the eighth and the 44th days;
FIG. 2 illustrates an increase in number of hepatocytes;
FIGS. 3(a), (b) and (c) are micrographs (100, 606 and 606 magnification, respectively) of immunocytochemistry (on the 30th, the 46th and the 50th days of first subculture, respectively) illustrating incorporation of BrdU into hepatocytes, a stain of transferrin and stains of α-antitrypsin and albumin;
FIGS. 4(a) and 4(b) are phase contrast photomicrographs (29.4 magnification) of second subculture hepatocyte-clusters on the fourth and the 42nd days; and FIGS. 4(c) and 4(d) are photomicrographs (606 magnification) of immunocytochemical figures illustrating stains of albumin and transferrin, respectively, on the 52nd day;
FIGS. 5(a) and (b) are photomicrographs (200 and 242 magnification) of desmin immunocytochemical figure illustrating the state of non-parenchymal hepatic cells of the first subculture on the 30th day, and esterase enzyme-cytochemical figure on the 38th day;
FIG. 6 is a phase contrast photomicrograph (76 magnification) of a first subculture on the 32nd day illustrating the hepatic cord-like structure of hepatocytes;
FIGS. 7(a) and (b) are a phase contrast photomicrograph (29.4 magnification) illustrating the state on the 15th and 22nd days of first subculture as a control, and a photomicrograph (30 magnification) of a transferrin immunostaining figure, respectively;
FIGS. 8A and 8B are photomicrographs illustrating the effects on hepatocytes and non-parenchymal hepatic cells when removing EGF corresponding to FIGS. 7A and 7B;
FIGS. 9A and 9B are photomicrographs of a case similar to that shown in FIGS. 7A and 7B, in which nicotinamide is removed;
FIGS. 10A and 10B are photomicrographs of a case similar to that shown in FIGS. 7A and 7B, in which L-ascorbic acid 2-phosphate is removed;
FIGS. 11A and 11B are photomicrographs of a case similar to that shown in FIGS. 7A and 7B, in which DMSO is removed;
FIG. 12 illustrates changes with time in the area of hepatocyte clusters after subculture in cases where EGF, nicotinamide, L-ascorbic acid 2-phosphate and DMSO are removed, respectively;
FIG. 13 illustrates the area occupied by anti-transferrin positive cells on the 22nd day of subculture when removing EGF, nicotinamide, L-ascorbic acid 2-phosphate and DMSO, respectively;
FIG. 14 is a phase contrast photomicrograph (147 magnifications) illustrating the state on the third day of culture of cells sampled from a rat having an age of eight weeks;
FIG. 15 is a phase contrast photomicrograph illustrating the state of the same cell as that shown in FIG. 14 on the fifth day of culture within the same field of view;
FIG. 16 is a phase contrast photomicrograph illustrating the state of the same cell as that shown in FIG. 14 on the 15th day of culture within the same field of view;
FIG. 17 illustrates the relationship between the age in weeks of the rat from which cells are sampled and the number of hepatocyte colonies per cm 2 on the tenth day of culture;
FIG. 18 illustrates the relationship between days in culture and the area of hepatocyte colonies for each age in week of the rats;
FIG. 19 is a photomicrograph (75.8 magnifications) illustrating an HE staining figure of hepatocyte colonies on the 10th day of culture of cells sampled from a rat having an age of eight weeks;
FIG. 20 is a photomicrograph (75.8 magnifications) illustrating HE staining figure of hepatocyte colonies on the 20th day of culture of cells sampled from the same rat as in FIG. 19;
FIG. 21 is a photomicrograph (200 magnifications) illustrating a BDI staining figure of a hepatocyte colony on 30th day of culture of cells sampled from a rat having an age of seven weeks;
FIG. 22 is a photomicrograph (152 magnifications) illustrating a cytochalasin 7 staining figure of a hepatocyte colony on the 25th day of culture of cells sampled from a rat having an age of eight weeks;
FIG. 23 is a photomicrograph (606 magnifications) illustrating an albumin staining figure of a hepatocyte colony on the 25th day of culture of cells sampled from a rat having an age of eight weeks;
FIG. 24 is a photomicrograph (242 magnifications) illustrating an α 1 -antitrypsin staining figure of a hepatocyte colony on the 25th day of culture of cells sampled from a rat having an age of eight weeks;
FIG. 25 is a photomicrograph (606 magnifications) illustrating a transferrin BrdU double staining figure of a hepatocyte colony on the 30th day of culture of cells sampled from a rat having an age of seven weeks;
FIG. 26 is a photomicrograph (152 magnifications) illustrating an α-fetoprotein staining figure of a hepatocyte colony on the 30th day of culture of cells sampled from a rat having an age of seven weeks;
FIG. 27 is a photomicrograph (152 magnifications) illustrating a GST-P staining figure of a hepatocyte colony on the 30th day of culture of cells sampled from a rat having an age of seven weeks;
FIG. 28 is a photomicrograph (152 magnifications) illustrating a γ-GTP staining figure of a hepatocyte colony on the 30th day of culture of cells sampled from a rat having an age of seven weeks;
FIG. 29 is a photomicrograph (152 magnifications) illustrating an OC2 staining figure of a hepatocyte colony on the 22nd day of culture of cells sampled from a rat having an age of ten weeks;
FIG. 30 is a photomicrograph (152 magnifications) illustrating an OC3 staining figure of a hepatocyte colony on the 22nd day of culture of cells sampled from a rat having an age of ten weeks;
FIG. 31 is a photomicrograph (242 magnifications) illustrating a desmin staining figure of a hepatocyte colony on the 25th day of culture of cells sampled from a rat having an age of eight weeks;
FIG. 32 is a photomicrograph (29.4 magnifications) illustrating a phase contrast figure of hepatocyte colonies on the 31st day of culture of cells sampled from a rat having an age of eight weeks, as cultured in a system (control) added with all the additive factors into the medium;
FIG. 33 is a phase contrast photomicrograph illustrating the effect on hepatocytes and non-parenchymal cells when removing EGP corresponding to FIG. 32;
FIG. 34 is a phase contrast photomicrograph illustrating the effect on hepatocytes and non-parenchymal cells when removing nicotinamide corresponding to FIG. 32;
FIG. 35 is a phase contrast photomicrograph illustrating the effect on hepatocytes and non-parenchymal cells when removing L-ascorbic acid phosphate corresponding to FIG. 32;
FIG. 36 is a phase contrast photomicrograph illustrating the effect on hepatocytes and non-parenchymal cells when removing DMSO corresponding to FIG. 32;
FIG. 37 is a phase contrast photomicrograph illustrating the effect on hepatocytes and non-parenchymal cells when removing FBS corresponding to FIG. 32;
FIG. 38A and 38B are transmission electron microscopic photomicrographs (d: 4,250 magnifications, b: 21,300 magnifications) of a hepatocyte colony on the tenth day of culture of cells sampled from a rat having an age of eight weeks.
DETAILED DESCRIPTION OF THE INVENTION
First, the subculturing system of the present invention is described below in detail.
More particularly, in the subculturing system of the present invention, it is possible to cause growth of hepatocytes after subculture and to maintain functions of hepatocytes for a long period of time, by adding nicotinamide and ascorbic acid into the medium of primary cells.
Conventional and other media and additives may be appropriately used. More specifically, an example is a medium system prepared by adding nicotinamide and ascorbic acid to a DMEM medium, and further adding fetal bovine serum (FBS) and epidermal growth factor (EGF).
It is needless to mention that applicable nicotinamides and ascorbic acids include, in addition to conventional ones, nicotinamide alkyls, cycloalkyls and ones having substituents, and phosphoric ester, phosphorous ester, sulfonic ester of ascorbic acid, alkyls thereof, and analogs having substituents.
Then, the method for obtaining liver parenchymal cells having a clonal growth ability of the present invention is described below in detail.
While it is the usual practice for sampling hepatocytes to obtain a heavy fraction by centrifuging at a low speed (50 G), the method of the present invention comprises separating a light fraction resulting from centrifuging at the low speed, and culturing cells contained in this light fraction. FBS and an ascorbic acid (for example, L-ascorbic acid phosphate) are added to a culture medium. As is clear from test results in the Examples described later, these constituents cause formation of colonies of small hepatocytes in the light fraction (non-parenchymal cell fraction). EGF and dimethyl sulfoxide (DMSO), not being essential for the formation of colonies, have a function of accelerating formation of colonies, and nicotinamides are considered to inhibit differentiation of hepatic cells, and are therefore preferable as constituents to be added to the culture medium. In addition to small hepatocytes, the non-parenchymal cell fraction contains endothelial cells, Kupffer cells, stellate cells and bile duct cells, which are considered to provide a special environment for small hepatocytes. The above-mentioned nicotinamides, ascorbic acids and DMSO inhibit growth of non-parenchymal cells, and permit selectively causing culturing and growth of small parenchymal cells.
The amounts of additives to the medium may be as follows: 5 to 30% FBS, 0.1 to 1.0 mM ascorbic acid, 1 to 100 ng/ml EGF, 1 to 20 mM nicotinamide, and about 0.1 to 2% DMSO.
Culture is accomplished at a temperature of about 37° C. under conditions including 5% CO 2 .
The liver parenchymal cells thus obtained can be subcultured by detaching cells of colony from the culture dish with a solution of EDTA (0.002-0.2% EDTA) or a solution of EDTA and trypsin (0.002-0.2% EDTA and 0.005-0.5 trypsin), and then re-culturing the detached cells in the same medium as that for primary culture. Alternatively, it is possible and preferable to use the conditioned medium of the primary culture itself as the medium for subculturing. Especially, use of the conditioned medium is adequate in the case where the cells of colony being detached from the dish with the solution of EDTA/trypsin and being separating into individual cells by means of, for example, a filtration. By using these procedures, the liver paranchymal cells of the present invention can he subcultured for a long period with a state of possessing an active growth ability and properties of hepatic cells.
Through the culture as described above, colonies of small hepatocytes clonally growing are available. Expression of differentiating function of cells forming the colonies as hepatic cells can be confirmed by conducting screening by the use of at least one of such indicators as the presence of peroxyzome, being positive to hepatocyte-markers, to neoplastic hepatocute-markers, to immature hepatocyte-markers, to antibodies against the surface antigens of ovall cells, and to bile duct cell-markers. Among others, the presence of peroxisome can be confirmed by observation with a transmission electron microscope. Applicable hepatocyte-markers include such antibodies as albumin α 1 antitrypsin and transferrin; applicable markers of neoplastic hepatocyte or immature hepatocyte include such antibodies as GST-P and α-fetoprotein and γ-GTP stain; applicable antibodies against surface antigen of ovall cells include the antibody (OC2, OC3) prepared by Hixson et al. mentioned above; and applicable markers of bile duct cells include such antibodies as BDL (prepared by Hixson et al.) and cytokeratin 7. By using a marker for stellate cells, it is possible to identify non-parenchymal cells.
As described above, the methods of the present invention are applicable to hepatocytes of human and all other mammals, thus permitting obtaining liver parenchymal cells having a clonal growth ability from various animal species. For example, liver parenchymal cells having a clonal growth ability sampled from a human liver can be utilized for preparation of a hybrid type-artificial liver, and is expected to bring about new aspects of development of therapeutic techniques of hepatic diseases.
EXAMPLES
Now, the present invention is described in further detail by means of examples, and at the same time, properties of the subculture hepatocytes having a clonal growth ability thus obtained are described in detail with reference to test results. It is needless to mention that the present invention is not limited to the examples presented below.
Example 1
Primary hepatocytes were subcultured by using the subculturing system of the present invention.
TABLE 1 illustrates an example of configuration of the subculturing system of the present invention.
In accordance with TABLE 1, hepatic cells were isolated by the collagenase perfusion method from F344 male rats having ages ranging from four to eight weeks. The hepatic cells were cultured with a concentration of 6.7×10 4 cells/cm 2 on a DMEM medium added with 10% FBS, 10 ng/ml EGF, 10 mM nicotinamide, and 0.2 mM L-ascorbic acid phosphate, and 1% DMSO was added from the fourth day of culture. To detach the hepatocytes from the dish, 0.02% EDTA was used. BrdU was incorporated as an indicator of growth of the hepatocytes. The area of the hepatocyte region was measured by taking photographs periodically of the same field under a phase contrast microscope. Identification or functional expression and non-parenchymal cells was accomplished by using an immunocytochemical technique or an enzyme-cytochemical technique.
TABLE 1______________________________________F344 Rat ♂ 4˜8 weeks old ↓ Isolation of Hepatic Cells (Collagenase Perfusion) ↓Percoll Centrifugation ↓ Hepatocytes 6 × 10.sup.5 cells ./. 3.5 cm dish (without collagen coat) 37° C., 5% CO.sub.2, 95% Air DMEM, 44 mM NaHCO.sub.3, 20 mM HEPES, 0.5 mg/I Insulin 10.sup.-7 M Dexamethasone, 30 mg/I L prolin penicillin and streptmycin ↓ 2˜3 hoursMedium Change DMEM, 10% FBS, 44 mM NaHCO.sub.3, 20 mM HEPES 0.5 mg/I Insulin, 10.sup.-7 M Dexamethasone 10 mM Nicotinamide. 10 ng/ml EGF 0.2 mM L-ascorbic acid phosphate penicillin and streptmycin ↓ 4 days Pre-confluent Subculture with 0.02% EDTA 1% DMSO______________________________________
The same operations were carried out through systems added with additive factors such as FCS, nicotinamide, EGF, L-ascorbic acid phosphate except for one, to investigate the effects of the individual additives on the hepatocytes and the non-parenchymal cells.
As a result of the above, a treatment with 0.02% EDTA caused the hepatocytes to detach them in the form of clusters, and as shown in FIG. 1 (first subculture×29.4), the clusters adhered to the dish within one or more days of subculture (FIG. 1(a): the second day of subculture), grew from the third day or so of subculture (FIG. 1(b): the fifth day of subculture), and part of cells died and peeled off on seventh day or so of subculture (FIG. 1(c): the eighth day of subculture).
About the eighth day or so of subculture and thereafter, the surviving hepatocytes grew (FIG. 1(d): the 44th day of subculture), and in the case of most proliferative clusters, the number of hepatocytes increased 5-fold on the 41th day of subculture (FIG. 2).
Growth of the hepatocytes after subculture was confirmed from the increase in number of the hepatocyte clusters, incorporation of BrdU, and mitotic figure. Incorporation of BrdU was observed in many hepatocytes on the 30th day of subculture (FIG. 3(a)). FIGS. 3(a), (b) and (c) show the 30th, the 45th and the 50th days of the first generation of subculture, respectively.
In FIG. 3(a), double staining (×100) was applied with BrdU (brown)-transferrin (red); FIG. 3(b) is based on stain (×606) with α 1 -antitrypsin (brown); and in FIG. 3(c), staining (×606) was applied with albumin (brown). In the hepatocytes continuing to grow after subculture, expression of albumin, α 1 -antitrypsin, and transferrin was observed.
The state of the second-generation hepatocyte clusters in subculture is illustrated in FIGS. 4(a), (b), (c) and (d). FIG. 4(a) shows a phase contrast figure (×30) on the fourth day of subculture, and FIG. 4(b) shows that on the 42nd day of subculture, both within the same field of view. FIG. 4(c) shows albumin (brown) staining (×606) on the 52nd day of subculture, and FIG. 4(d) shows transferrin (brown) staining (×606) on the 52nd day of subculture. Detaching the hepatocytes on the 35th day of subculture with 0.02% EDTA permitted observation of growth of the hepatocytes adhering again to the dish. The second-generation hepatocyte clusters in subculture were positive to albumin and transferrin.
As shown, for example, in FIG. 5(a) illustrating the confirmation of positivity in desmin (brown) staining (×200) on the 30th day of subculture, and in FIG. 5(b) illustrating the confirmation of negativity (although the hepatic cells are partially positive) in esterase (brown) staining (×242) on the 38th day of subculture, non-parenchymal cells began growing around the hepatocyte clusters on the fourth day of subculture, and on the 30th day, the hepatocyte clusters were almost completely surrounded. These non-parenchymal cells, being highly positive in desmin, were considered to be stellate cells. These were not considered to be Kupffer cells because esterase activity was negative.
As is clear from FIG. 6 (×76) showing the hepatic cord-like structure of the hepatocytes as a phase-contrast figure on 32nd day of subculture (first generation of subculture), a maltilayered structure of the hepatocytes was observed after the subculture, and a sequence suggesting a hepatic cord-like structure was partially observed.
FIG. 7 (control), FIG. 8 (without EGF) FIG. 9 (without nicotinamide) FIG. 10 (without L-ascorbic acid-phosphate) and FIG. 11 (without DMSO) illustrate the effects of these additive factors on hepatocytes and liver parenchymal cells, in the form of phase-contrast figures (×29.4) on the 15th day of subculture and transferrin-stained figures (red) (×30) on the 22nd day of subculture.
FIG. 12 shows the effects of these additive factors as changes with time in the area of hepatocyte clusters, with that on the first day of subculture as 100%.
Similarly, FIG. 13 demonstrates the effects of the individual additive factors by means of the area of anti-transferrin positive cells on the 22nd day of subculture, with that for the control as 100%.
As is evident from these drawings, inhibition of growth of hepatocytes after subculture was observed in all the systems removing any of EGF, nicotinamide, and L-ascorbic acid-2-phosphate. In the system removing EGF, inhibition of growth of non-parenchymal cells was observed, whereas acceleration of growth of non-parenchymal cells was observed in the system not containing nicotinamide. In the system removing DMSO, growth of non-parenchymal cells was earliest: the hepatocyte clusters began to peel off from the dish on the 22nd days. In all the systems, the hepatocytes were transferrin-positive. In the system not containing FBS, remarkable inhibition of growth of hepatocytes and non-parenchymal cells was observed.
As is clear from these results, the hepatocytes detached in the state of clusters and could adhere to the dish and grow in a system formed by adding FBS, EGF, nicotinamide, L-ascorbic acid-phosphate and DMEM to DMEM and treating these cells with 0.02% EDTA in a confluent state.
Because the dish was not coated with collagen, the hepatocytes could be detached with 0.02% EDTA. By treating with 0.02% EDTA and 0.25% trypsin, the hepatocytes detached in the form of single cells, adhering to the dish, and incorporation of many BrdU was observed. On the seventh day, some hepatocytes died, and thereafter, the status of growth and maintenance of the remaining hepatocytes was poorer then with 0.02% EDTA.
EGF, which had functions of accelerating growth of the hepatocytes and non-parenchymal cells and causing the hepatocytes after subculture to survive, and nicotinamide, which had a function of accelerating growth of "committed progenitor cells," were both essential for the subject system.
L-ascorbic acid-phosphate, which had functions of accelerating growth of the hepatocytes and causing the hepatocytes after subculture to survive, was essential in the system. Various effects of L-ascorbic acid-2-phosphate on hepatocytes and fibroblasts have been reported, and it is considered to have contributed in the system of the present invention to interaction between non-parenchymal and hepatocytes and three-dimensional structure.
DMSO has a function of inhibiting growth of non-parenchymal cells.
In the system of the present invention, "committed progenitor cells" could selectively be cultured by subculturing hepatocytes under conditions permitting growth of hepatic "committed progenitor cells."
Example 2
Hepatic cells having a clonal growth ability of the present invention were obtained as follows.
(1) Culture of Hepatocytes
Cells of liver were sampled from F344 male rats of ages ranging from 4 to 22 weeks by the collagenase perfusion method and centrifuged at a speed (50 g, 1 minute×3). The resultant supernatant was further centrifuged at a speed (150 g, 5 minutes×3), thereby obtaining a non-parenchymal cell fraction as precipitate. These cells were inoculated at 9×10 5 cells per culture dishes having a diameter of 3.5 cm and cultured at 37° C. with 5% CO 2 for two to three hours in a DMEM medium (containing 10% FBS, 44 mM NaHCO3, 20 mM HEPES, 0.5 mg/l insulin, 10 -7 dexamethasone, 30 mg/l L-proline, penicillin and streptomycin). Then, the medium was replaced with a DMEM medium formed by adding 10 mM nicotinamide, 10 ng/ml EGF and 0.2 mM L-ascorbic acid phosphate to the above-mentioned medium, and another medium further added with 1% DMSO was used on the fourth and subsequent days to continue culture.
(2) Procedures
BrdU was incorporated and photographs of the same fields were taken periodically under a phase contrast microscope to measure the area of the hepatocyte region as indicators of the growth of hepatocytes.
Identification of functional expression of the hepatocytes and non-parenchymal cells was accomplished by an immunocytochemical technique or an enzyme-cytochemical technique using antibodies (OC2, OC3) of ovall cells obtained by Hixson as described above, bile duct cell-markers (BD1: obtained by Hixson as presented above; cytochalasin 7), hepatocyte-markers (antibody against albumin, α 1 -antitrypsin and transferrin), neoplastic hepatocyte- or immature hepatocyte-markers (antibodies against GST-P, α-fetoprotein, γ-GTP stain), and stellate cell-markers (antibody of desmin). Organelles were observed in detail with a transmission electron microscope.
To compare differences in the results of culture between ages in weeks of rats from which hepatic cells were sampled, samples on the tenth day of culture was HE-stained, and the forming ability of hepatocyte colonies was measured under a microscope. Collections each having 8 or more cells were counted as colonies.
Culture was conducted in systems removing each of such additive factors from the medium as FBS, nicotinamide, EGF, L-ascorbic acid phosphate and DMSO to investigate the effects of the individual additive factors on hepatocyte colonies and non-parenchyma cells.
(3) Results
As a result of culture under the conditions shown in (1) above, small hepatocytes were observed to form colonies and clonally grow, as shown in phase-contrast photomicrographs in FIGS. 14 to 16. These FIGS. 14 to 16 are phase contrast figures (147 magnifications) of the same field of view of cell culture sampled from rats having an age of eight weeks: a single small hepatic cell on the third day of culture (FIG. 14) grows into four cells on the fifth day (FIG. 15) and into about 300 cells in a colony on the 15th day (FIG. 16).
The colony froming ability decreased as the age in weeks of the rat from which hepatic cells were sampled increased as shown in FIG. 17. Irrespective of the age in weeks of rat, the growth curves were almost identical as shown in FIG. 18. These results suggest that hepatic cells forming colonies are progenitor cells.
From the result of HE staining, large binuclear cells were observed in colonies and maltilayered structures in peripheral area of colonies on the 20th day of culture (FIG. 20) although the colonies consisted of homogeneous small hepatocytes on the tenth day of culture (FIG. 20). In some portion of colonies, positive cells to bile duct cell-markers, BD1 (FIG. 22) and cytochalasin 7 (FIG. 22) were observed. From these results, cells of colonies are considered to contain progenitor cells of bile duct cells or to be stem cells capable of differentiating into hepatocytes or bile duct cells.
Then, these colonies of cells were confirmed to be positive to the hepatocyte-markers, and comprise cells expressing normal functions. More specifically, FIG. 23 is a photomicrograph of albumin-stained colonies, and FIG. 24 is a photomicrograph of α 1 -antitrypsin-stained colonies. In the results of double staining with transferrin and BrdU, incorporation of BrdU into cells positive to transferrin was observed as shown in FIG. 25. The cells of these colonies were partially positive to neoplastic hepatocyte- or immature hepatocyte-markers (FIG. 26; α fetoprotein stoin; FIG. 27; GST-P stain; and FIG. 28: γ-GTP stain), and positive to antibodies of ovall cells (FIG. 29: OC2 stain; FIG. 30: OC3 stain).
On the other hand, part of non-parenchymal cells around colonies were positive to desmin antibody which was a stellate cell-marker. However because negative cells were also observed (FIG. 31), presence was confirmed of many non-parenchymal cells other than stellate cell around the colonies.
TABLE 2 shows the results of the test on samples removing each of the additive factors from the medium. In this test, culture dishes on the 31st day of culture were stained with albumin, the number of hepatocyte colonies per cm 2 was counted with a mass containing eight or more cells positive to albumin counted as one colony. The average of the thus counted numbers of colonies (n=3) is shown in TABLE 2. Phase contrast photomicrographs of colonies for the system containing all the additive factors and the systems removing each of the additive factors are shown in FIGS. 32 to 37.
TABLE 2______________________________________ Number of hepatic cell colonies Non-parenchymal Medium (average ± SD) cell______________________________________Control 67.5 ± 6.4 + EGF(-) 16.8 ± 8.1 + Nicotinamide(-) 66.6 ± 1.9 ++ L-ascorbic acid phosphate(-) 1.0 ± 1.9 ++ DMSO(-) 24.8 ± 4.8 ++ FBS(-) 0 -______________________________________
As is clear from TABLE 2, there was no difference in growth of non-parenchymal cells as compared with the control in the system removing EGF in which formation of hepatocyte colonies was apparently inhibited (see FIGS. 32 and 33). In the nicotinamide (-) system, on the other hand, while growth of non-parenchymal cells was accelerated, the forming ability of hepatocyte colonies was not affected. In this nicotinamide (-) system, however, the hepatic cells exhibited a large in size, a hepatic cord-like structure, and form expressing the highly differentiated character of hepatocytes at compared with the control (FIG. 34). In the L-ascorbic acid phosphate (-) system, growth or non-parenchymal cells was accelerated, whereas almost no hepatocyte colonies were formed (FIG. 35). In the DMSO (-) system, growth of non-parenchymal cells was accelerated, but the forming ability of hepatocyte colonies was low as compared with the control (FIG. 36). In the FBS (-) system, both non-parenchymal and hepatocytes would not continue to live (FIG. 37).
These results permitted confirmation that, in order to obtain liver paranchymal cells of the present invention, addition of FBS and ascorbic acid to the culture medium is essential EGF and DMSO, not essential for forming hepatocyte colonies, have a function of accelerating formation of hepatocyte colonies, and nicotinamide is a factor having a relationship with differentiation of hepatocytes. Nicotinamide, ascorbic acid and DMSO were recognized to have a function of inhibiting growth of non-parenchymal cells.
Finally, peroxisome which is a feature of hepatocyte was observed in the cytoplasm of the cells forming the colonies from the observation with a transmission electron microscope (FIGS. 38a and b).
Example 3
Liver paranchymal cells obtained by the same method as in EXAMPLE 2 were subcultured by the method of the present invention.
Culture medium was removed from the dish on which small hepatocytes form colonies, and the colonies were treated with 0.02% EDTA at 37° C. for about 10 minutes, thereby the colonies were detached from the dish. On replacing the colonies on a dish filled with the same medium as that for the primary culture, the small hepatocyte colonies and non-parenchymal cells around the colonies adhered on the dish and started to proliferate.
The liver parenchymal cells were subcultures by another procrdure. That is, after removing culture medium, the colonies were treated with 0.02% EDTA and 0.05% trypsin, thereby the colonies were dispersed into individuals of small hepatocytes and non-parenchymal cells. By pippetting the solution, small hepatocytes- and non-parenchymal cells-dispersed solution were obtained. Then, each of the solution was filtrated with 20 μm filter and aggergate of cells was removed, separated individuals of cell were obtained. The individuals of hepatocyte and non-parenchymal cell thus obtained were observed to adhere on dish, but only non-parenchymal cells proliferate in the same medium as that for the primary culture. In the conditioned medium of being used at the primary culture (1-4 days), small hepatocytes were observed to form a colony and proliferate. From these results, it was confirmed that the conditioned medium is necessary for subculturing small hepatocytes. | The present invention provides liver parenchymal cells having a clonal growth ability, which possesses at least one of the cell biological properties such as: presence of peroxysome; being positive to hepatocyte-markers; being partially positive to neoplastic hepatocyte-markers or immature hepatocyte-markers; being positive to antibodies against the surface antigens of ovall cells; and being partially positive to bile duct cell-markers. The present invention also provides a method for obtaining such cells and a method for subculturing such cells.
With the liver parenchymal cells above, it will be possible to research in detail the process of development and differentiation, the mechanisms of growth and functional expression of hepatic cells, and to open up a new way to clalification of mechanisms or hepatoma and various other diseases and to development of therapeutic method against these disseases. | 2 |
RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 10/268,578, filed Oct. 10, 2002 now U.S. Pat. No. 6,716,682, entitled “SOI CMOS DEVICE WITH REDUCED DIBL” which is a continuation of U.S. patent application Ser. No. 09/652,864, filed Aug. 31, 2000, entitled “SOI CMOS DEVICE WITH REDUCED DIBL” (now U.S. Pat. No. 6,503,783).
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of semiconductor devices and fabrication processes and, in particular, to CMOS devices formed in a silicon-on-insulator (SOI) technology with reduced drain induced barrier lowering (DIBL) and a method for fabricating the sane.
2. Description of the Related Art
There is an ever-present desire in the semiconductor fabrication industry to achieve individual devices with smaller physical dimensions. Reducing the dimensions of devices is referred to as scaling. Scaling is desirable in order to increase the number of individual devices that can be placed on a given area of semiconductor material and to increase the process yield and to reduce the unit cost of the devices and the power consumption of the devices. In addition, scaling can result in performance increases of the individual devices as the charge carriers with a finite velocity have a shorter distance to travel and less bulk material has to accumulate or dissipate charges. Thus, the trend in the industry is towards thinner device regions and gate oxides, shorter channels, and lower power consumption.
However, scaling often creates some performance drawbacks. In particular, a known category of performance limitations known as short channel effects arise as the length of the channel of CMOS devices is reduced by scaling. One particular short-channel effect in CMOS devices, known as Drain Induced Barrier Lowering (DIBL) is mainly responsible for the degradation of sub-threshold swing in deep submicron devices. DIBL is a reduction in the potential barrier between the drain and source as the channel length shortens as illustrated in FIG. 1 reflecting known prior art. When the drain voltage is increased, the depletion region around the drain increases and the drain region electric field reduces the channel potential barrier which results in an increased off-state current between the source and drain.
In conventional CMOS devices, a retrograde channel dopant profile can be effectively used to control DIBL. In a CMOS process, n-type and p-type wells are created for NMOS and PMOS devices. In a typical diffusion process, dopant concentration profiles in these n- and p-type wells are at a peak near the surfaces and decrease in the depth direction into the bulk as illustrated in FIG. 2. A retrograde profile is one in which the peak of the dopant concentration profile is not at the surface but at some distance into the bulk as shown in FIG. 3 . Such retrograde profiles are helpful in deep submicron CMOS devices since they reduce the lowering of the source/drain barrier when the drain is biased high and when the channel is in weak inversion. This limits the amount of subthreshold leakage current flowing into the drain. A lower level of subthreshold leakage current provides improved circuit reliability and reduced power consumption.
A retrograde dopant profile also typically results in a lower dopant concentration near the surface of the wafer which reduces junction capacitances. Reduced junction capacitances allow the device to switch faster and thus increase circuit speed. Typically, retrograde profile dopant implants are done after formation of the gate. A halo (or pocket) implant is another known method used in deep submicron CMOS devices to reduce DIBL.
However in some applications, such as in an SOI process, it is difficult to create a retrograde profile due to the thinness of the silicon layer and the tendency of the dopants to diffuse. A SOI process has a buried insulating layer, typically of silicon dioxide. State-of-the-art SOI devices have a very thin silicon (Si) film (typically <1600 Å) overlying the oxide in which the active devices are formed. Increasing the Si film thickness any further will increase the extent to which the devices formed therein get partially depleted. SOI devices also suffer from ‘floating body’ effects since, unlike conventional CMOS, in SOI there is no known easy way to form a contact to the bulk in order to remove the bulk charges.
When the as-implanted retrograde dopant profiles diffuse during subsequent heat cycles in a process, they spread out and lose their ‘retrograde’ nature to some extent. In SOI, since the silicon film is very thin, creating a true retrograde dopant profile is very difficult. This is true even while using higher atomic mass elements like Indium (In) for NMOS and Antimony (Sb) as channel dopants. Diffusivity of these dopants in silicon is known to be comparable to lower atomic mass elements like boron (B) and phosphorus (P), when the silicon film is very thin, as in an SOI technology. Moreover, leakage current levels are known to increase when Indium is used for channel dopants (See “Impact of Channel Doping and Ar Implant on Device Characteristics of Partially Depleted SOI MOSFETs”, Xu et al., pp. 115 and 116 of the Proceedings 1998 IEEE International SOI Conference, October, 1998 and “Dopant Redistribution in SOI during RTA: A Study on Doping in Scaled-down Si Layers”, Park et al. IEDM 1999 pp. 337-340, included herein by reference).
From the foregoing it can be appreciated that there is an ongoing need for a method of fabricating deep submicron SOI CMOS devices while minimizing short channel effects such as DIBL. There is a further need for minimizing DIBL in deep submicron CMOS devices without incurring significant additional processing steps and high temperature processing.
SUMMARY OF THE INVENTION
The aforementioned needs are satisfied by the SOI CMOS device with reduced DIBL of the present invention. In one aspect, the invention comprises a semiconductor transistor device comprising: a semiconductive substrate; an insulative layer buried within the semiconductive substrate; an active layer of semiconductive material above the insulative layer, a plurality of doped device regions in the active layer; a gate structure formed on the device regions; source and drain regions formed in the device regions such that the doping type for the source and drain is complementary to the doping type of the corresponding device region; dopant diffusion sources placed within the buried insulator layer underlying the device regions wherein the dopant diffusion sources diffuse into the device regions so as to create a retrograde dopant profile in the device regions; a plurality of conductive layers electrically interconnecting the transistor devices; and a passivation layer overlying the conductive layers. In one embodiment, the semiconductive substrate, insulative layer buried within the semiconductive substrate, and the active layer of semiconductive material above the insulative layer comprise a SOI Separation by IMplanted OXygen (SIMOX) wafer.
Another aspect of the invention comprises dopant atoms implanted through the device regions such that the dopant atoms come to reside within the Buried OXide (BOX) layer underlying the device regions creating a borophosphosilicate glass (BPSG) within the BOX layer. Formation of the passivation layer causes the dopant atoms contained within the BPSG to diffuse into the device regions so as to create the retrograde dopant profile in the device regions. The retrograde dopant profile has a peak concentration substantially adjacent the interface of the BOX and the active region. The retrograde dopant profile in the device region provides the transistor device with improved resistance to drain-induced barrier lowering (DIBL) and also provides the transistor device with recombination centers to reduce floating body effects.
In another aspect, the invention comprises a method for creating semiconductor transistor devices comprising the steps of: providing a semiconductor substrate; forming a buried insulation layer in the semiconductor substrate; forming an active layer above the buried insulation layer by placing additional semiconductor material on the buried insulation layer; doping the active layer with dopant atoms so as to form device regions; implanting additional dopant atoms through the device regions such that the additional dopant atoms come to reside within the buried insulation layer underlying the device regions; implanting dopant atoms into gate regions of the device regions; forming a gate stack on the active layer adjacent the gate regions; implanting dopant atoms into the device regions such that the dopant atoms come to reside within the device regions adjacent the gate regions so as to form source and drain regions and wherein the gate stack substantially inhibits penetration of the dopant atoms into the gate regions of the device regions; forming conductive paths that electrically connect to the source, drain, and gate regions; and forming a passivating layer overlying the conductive paths. The method of the invention also includes implanting dopant atoms through the device regions wherein the dopant atoms come to reside within the BOX layer underlying the device regions thereby creating a borophosphosilicate glass (BPSG) within the BOX layer.
In another aspect of the invention, formation of the passivation layer induces the dopant atoms contained within the BPSG to outdiffuse into the device regions thereby forming a retrograde dopant profile within the device regions. The retrograde dopant profile within the device regions reduces DIBL effects for the CMOS device and also provides recombination centers adjacent the BOX active region interface thereby reducing floating body effects. These and other objects and advantages of the present invention will become more fully apparent from the following description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph illustrating prior art concerning DIBL as the relation of threshold voltage (V T ) to drain-source voltage (V DS ) for various sub-micron channel lengths;
FIG. 2 is a graph illustrating prior art of a typical diffusion based dopant profile in CMOS devices;
FIG. 3 is a graph illustrating prior art of a retrograde dopant profile in CMOS devices;
FIG. 4 is a section view of the starting material of the SOI CMOS with reduced DIBL, a SIMOX wafer;
FIG. 5 is a section view of the SIMOX wafer with n- and p-type wells formed therein and a high dose, high energy implant into the buried oxide (BOX) forming a borophosphosilicate glass (BPSG) structure;
FIG. 6 is a section view of the SIMOX wafer with gate stacks formed on the n- and p-wells with source and drain implants;
FIG. 7 is a section view of the SOI CMOS devices with conductive and passivation layers in place with the dopants entrained within the BPSG outdiffused into the n- and p-wells thereby forming a retrograde dopant profile within the wells that reduces DIBL;
FIG. 8 is a graph illustrating the net dopant concentration in the channel (gate) region of a SOI CMOS of the present invention as a function of depth into the substrate from the surface to the buried oxide layer; and
FIG. 9 is a graph illustrating the dopant concentration in the source/drain regions of a SOI CMOS of the present invention as a function of depth in the substrate from the surface to the buried oxide layer.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will now be made to the drawings wherein like numerals refer to like structures throughout. FIG. 4 is a section view of one embodiment of the SOI CMOS with reduced DIBL 100 of the present invention showing the starting SOI material, a Separation by IMplanted OXygen (SIMOX) wafer 102 . The SIMOX wafer 102 is well known in the art and comprises a silicon substrate 104 in which a layer of the substrate 104 is converted to a buried silicon dioxide (BOX) 106 layer with a heavy oxygen implant and subsequent anneal. An epitaxial layer 110 of Si approximately 500 Å to 2500 Å thick is then grown on top of the BOX layer 106 . The BOX layer 106 of the SIMOX wafer 102 provides electrical insulation between the active region of the epitaxial layer 110 and the bulk silicon of the substrate 104 . Thus, active devices formed in the epitaxial layer 110 are electrically isolated from the semiconductive substrate 104 . The SIMOX wafer 102 also provides physical structure as well as reactive material for formation of the SOI CMOS with reduced DIBL 100 in a manner that will be described in greater detail below.
In the description of the SOI CMOS with reduced DIBL 100 that follows, a single CMOS 130 structure comprising PMOS 132 and NMOS 134 ( FIG. 7 ) devices will be used to illustrate the invention. It should be appreciated that the process herein described for one CMOS 130 device also applies to forming a plurality of SOI CMOS with reduced DIBL 100 devices. It should also be appreciated that the invention herein described can be modified by one skilled in the art to achieve a PMOS 132 , an NMOS 134 , or other technology employing the methods herein described without detracting from the spirit of the invention. It should also be understood that FIGS. 4-7 are illustrative and should not be interpreted as being to scale.
The method of forming the SOI CMOS with reduced DIBL 100 then comprises creating n-well 112 and p-well 114 regions as shown in FIG. 5 . The n-well 112 and p-well 114 regions are created, in this embodiment, by implanting a dose of approximately 1e13/cm 2 of P @ 60 keV to create the n-well 112 and a dose of approximately 1e13/cm 2 of B @ 30 keV to create the p-well 114 . The n-well 112 and p-well 114 are then driven at a temperature of approximately 800° C. for a period of approximately 30 minutes. The n-well 112 and p-well 114 provide regions for the subsequent formation of the PMOS 132 and NMOS 134 devices that comprise a CMOS 130 device (FIG. 7 ).
The method of forming the SOI CMOS with reduced DIBL 100 then comprises high energy, high dose n-type diffusion source 116 and p-type diffusion source 120 implants into the p-well 114 and n-well 112 respectively as shown in FIG. 5 . The n-type diffusion source 116 and p-type diffusion sources 120 comprise borophosphosilicate glass (BPSG). The n-type diffusion source 116 and p-type diffusion source 120 implant parameters should be tailored in such a way that the resultant n-type diffusion source 116 and p-type diffusion source 120 dopant profiles mainly reside in the BOX layer 106 . In one embodiment, the n-type diffusion source 116 implant comprises an implant of phosphorus through the n-well 112 of approximately 2.0e14/cm 2 @ 220 keV into the BOX layer 106 and the p-type diffusion source 120 implant comprises an implant of boron through the p-well 114 of approximately 2.0e14/cm 2 @ 100 keV into the BOX layer 106 . In this embodiment, the final n-type diffusion source 116 and p-type diffusion source 120 dopant concentration in the BOX 106 is preferably at least 10 20 cm −3 . As will be described in greater detail below, the diffusion sources 116 , 120 provide a source of dopant atoms that can diffuse into the wells 112 , 114 respectively to create a retrograde dopant profile.
The method of forming the SOI CMOS with reduced DIBL 100 then comprises threshold voltage (vt) adjust implants 122 , 124 as shown in FIG. 5 . The threshold voltage adjust implants 122 , 124 adjust the threshold voltage of the PMOS 132 and NMOS 134 devices either upwards or downwards in a manner known in the art. The threshold voltage adjust implants 122 , 124 comprise, in this embodiment, a PMOS gate adjust 122 implant of BF 2 at a dose of approximately 5e12 to 1e13 @ 25-35 keV and an NMOS gate adjust 124 implant of Arsenic at a dose of approximately 5e12 to 1e13 @ 35-50 keV. The PMOS gate adjust 122 and the NMOS gate adjust 124 modify the dopant concentration in the gate region of the PMOS 132 and NMOS 134 devices so as to adjust the resultant threshold voltage of the PMOS 132 and NMOS 134 devices to a desirable level.
The method of forming the SOI CMOS with reduced DIBL 100 then comprises formation of a gate stack 136 as shown in FIG. 6 . The gate stack 136 comprises a gate oxide 126 , sidewalls 140 , a nitride layer 142 , and doped polysilicon 144 . The gate oxide 126 in this embodiment comprises a layer of silicon dioxide approximately 50 Å thick. The gate oxide 126 electrically isolates the n-well 112 and p-well 114 regions of the epitaxial silicon 110 from overlying conductive layers that will be described in greater detail below. The sidewalls 140 comprise silicon dioxide that is grown and subsequently anisotropically etched in a known manner to create the structures illustrated in FIG. 6 . The sidewalls 140 electrically isolate the gate stack 136 from source/drain conductive layers and facilitates formation of source/drain extensions in a manner that will be described in greater detail below. The nitride layer 142 comprises a layer that is substantially silicon nitride approximately 450 Å thick emplaced in a known manner. The nitride layer 142 inhibits subsequent passage of Boron from the p+ polysilicon layer 144 . The doped polysilicon 144 comprises heavily p-type doped polysilicon for the PMOS 132 device and heavily n-type doped polysilicon for the NMOS 134 . The doped polysilicon 144 provides a reduced work function for the gates of the PMOS 132 and NMOS 134 ( FIG. 7 ) and thus a lower contact resistance and corresponding faster device response.
The method of forming the SOI CMOS with reduced DIBL 100 then comprises formation of the source 146 and drain 150 as shown in FIG. 6 . The source 146 and drain 150 are formed by implanting BF 2 with a dose of approximately 2e15/cm 2 @ 15 keV for the PMOS 132 and As with a dose of approximately 2e15/cm 2 @ 10 keV for the NMOS 134 . As can be seen from FIG. 6 the implantation of the source 146 and drain 150 is partially masked by the gate stack 136 and results in source/drain extensions 152 . The source/drain extensions 152 are lower concentration regions of the source 146 and drain 150 that partially extend under the sidewalls 140 . The source/drain extensions 152 reduce the peak electric field under the gate and thus reduce hot carrier effects in a known manner.
The method of forming the SOI CMOS with reduced DIBL 100 then comprises formation of a conductive layer 154 (FIG. 7 ). In this embodiment, the conductive layer 154 comprises a layer of metallic silicide (titanium silicide or cobalt silicide) emplaced in a well known manner. The conductive layer 154 is placed so as to be in physical and electrical contact with the source 146 , the drain 150 , and the doped polysilicon 144 of the gate stack 136 . The conductive layer 154 interconnects the CMOS 130 with other circuit devices on the SIMOX wafer 102 in a known manner.
The method of forming the SOI CMOS with reduced DIBL 100 then comprises formation of a passivation layer 156 ( FIG. 7 ) overlying the structures previously described. In this embodiment, the passivation layer 156 comprises a layer of oxide, BPSG, or polysilicon approximately 3000 Å thick formed in a known manner. The formation of the passivation layer 156 involves a high temperature process.
The n-type diffusion source 116 and the p-type diffusion source 120 previously implanted into the BOX layer 106 in the manner previously described serve as solid-sources for dopant diffusion. When the passivation layer 156 is formed on the SIMOX wafer 102 with attendant heat steps, dopants contained in the n-type 116 and the p-type 120 diffusion sources will outdiffuse into the epitaxial silicon 110 , creating a thin, highly doped retrograde profile region 160 as shown in FIG. 7 . In the case of the p-well 114 , the retrograde profile region 160 will comprise boron and, in the n-well 112 , the retrograde profile region 160 will comprise phosphorus. The retrograde profile region 160 layer will act as a punchthrough prevention layer to control DIBL.
FIG. 8 shows the net dopant profile in a vertical outline in the middle of the channel region. The boron concentration increases from 9.0e17/cm 3 to 2.0e18/cm 3 , which is nearly a 120% increase, at the BOX 106 /silicon substrate 104 interface. FIG. 9 shows the dopant profile in the source 146 and drain 150 regions. The source 146 and drain 150 implants in this embodiment of the SOI CMOS with reduced DIBL 100 reach close to the BOX layer 106 as can be seen from FIG. 9 . As such the source 146 and drain 150 implants will compensate the outdiffused dopants from the n-type 116 and p-type 120 diffusion sources in the retrograde profile region 160 close to the interface of the BOX 106 and the silicon substrate 104 . This will reduce the junction capacitance of the SOI CMOS with reduced DIBL 100 even further as compared to a process with halo implants.
The dopants contained within the retrograde profile region 160 will also create recombination centers near the BOX 106 /silicon substrate 104 interface. These recombination centers are an added benefit in the SOI CMOS with reduced DIBL 100 since the recombination centers tend to reduce the floating body effects in the SOI CMOS with reduced DIBL 100 .
Hence, the process of the illustrated embodiment provides a method in which a retrograde doping profile can be created in thin semiconductor active areas such as the active area used in silicon-on-insulator (SOI) applications. The process of the illustrated embodiment does not significantly add to the processing of the device as only discrete implantation steps are required and the diffusion is obtained through the additional thermal processing of the device. Thus, retrograde profiles can be created in a manner that does not significantly increase the processing costs of the device.
Although the preferred embodiments of the present invention have shown, described and pointed out the fundamental novel features of the invention as applied to those embodiments, it will be understood that various omissions, substitutions and changes in the form of the detail of the device illustrated may be made by those skilled in the art without departing from the spirit of the present invention. Consequently, the scope of the invention should not be limited to the foregoing description but is to be defined by the appended claims. | A CMOS device formed with a Silicon On Insulator (SOI) technology with reduced Drain Induced Barrier Lowering (DIBL) characteristics and a method for producing the same. The method involves a high energy, high dose implant of boron and phosphorus through the p- and n-wells, into the insulator layer, thereby creating a borophosphosilicate glass (BPSG) structure within the insulation layer underlying the p- and n-wells of the SOI wafer. Backend high temperature processing steps induce diffusion of the boron and phosphorus contained in the BPSG into the p- and n-wells, thereby forming a retrograde dopant profile in the wells. The retrograde dopant profile reduces DIBL and also provides recombination centers adjacent the insulator layer and the active layer to thereby reduce floating body effects for the CMOS device. | 7 |
TECHNICAL FIELD
The present invention relates to manifolds, and more particularly to a manifold for use in agricultural ammonia application systems.
BACKGROUND OF THE INVENTION
The required application rates of ammonia in pounds per acre are quite varied depending on the crop, rainfall, the quality of the soil, the previous crop, the type of seed, etc. In general, the more vegetation above the soil the greater the requirement for ammonia. Applicator knife spacing is generally greater for corn, sorghum and the larger grains than it is for wheat, rice and the smaller grains. Some crops are sensitive to nitrogen rate, for example, popcorn and rice are not very tolerant of over or under application, and therefore the distribution across the tool bar from the manifold to the applicator knives is very important.
Ammonia at one atmosphere has a dew point of -28° with a latent head of 598.3 BTU and is stored as a liquid in a pressurized container under pressure due to its own vapor pressure. Any drop in pressure of the system requires a related temperature drop. The temperature drop is provided by the vaporizing of liquid within the system.
The behavior of ammonia in a system applying it to the soil is very similar to the capillary control of a refrigerating system, where resistance to flow is thermal as well as physical. In the application of ammonia, it is desirable to overcome the thermal resistance of flow physically with throttling means within the meter. The thermal resistance to flow can be expressed as the reduction of mass per unit volume. The ideal manifold would be one that presents to each of the discharges a product of equal mass per unit volume and of equal velocity. At very low rates of application, the liquid and vapor will separate with the liquid seeking the inner surfaces of the manifold receiving less outside head. The usual manifold having some plugged outlets behaves very similar to the vapor degreaser only at a much lower temperature. Should there be three or more orificed outlets grouped with plugged outlets on either side, the refrigeration due to the pressure drop across the orificed outlets will provide more mass to the center outlet and this condition will perpetuate itself due to the temperature drop across the orifices.
Conventional manifolds presently in use have a fairly large, disc shaped, central interior with an inlet at the top. Better manifolds have a screen separating the inlet from the discharges, such as manifold No. A60075, manufactured by Continental NH 3 Products Co. of Dallas, Tex. John Blue Co. manufactures an adjustable orificed 24 outlet manifold, its manifold No. A-6600.
SUMMARY OF THE INVENTION
A manifold for receiving metered anhydrous ammonia that is a variable combination of liquid and vapor routes the ammonia to the outlets of an applicator for proper injection into the soil by continually accelerating the ammonia as it approaches a discharge member having a plurality of discharge ports evenly spaced and retained between a body member and a bonnet member to form a restriction of equal value for each discharge port.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the invention and its advantages will be apparent from the Detailed Description taken in conjunction with the accompaning Drawings in which:
FIG. 1 is a side view of the assembled manifold;
FIG. 2 is a sectional view taken along lines 2--2 of FIG. 2;
FIG. 3 is a partially broken-away side view of a discharge port showing the use of spacers to increase the spacing of the gap adjacent each discharge orifice.
DETAILED DESCRIPTION
Referring initially to FIGS. 1 and 2, the manifold of the present invention includes a body member 10 having an inlet 12 defined by horizontally cylindrical wall 14 about an inlet axis 16. In the preferred embodiment, wall 14 is threaded to accept a conventional fitting. Body member 10 further includes a vertically cylindrical upper wall 18 and a horizontally planar lower wall 20 defining a receiving chamber 22 in communication with inlet 12. The receiving chamber upper wall 18 is cylindrical about a main axis 24 intersecting inlet axis 16. A raised internal threaded boss 26 extends from the receiving chamber lower wall 20, with threads 28 being circular about main axis 24. Boss 26 includes a boss upper surface 30. Screen 32 extends from boss upper surface 30 to the receiving chamber upper wall 18. Screen 32 is frustro-conical about main axis 24.
Screen 32 separates the receiving chamber 22 from an accelerating chamber 34. Accelerating chamber 34 is formed by converging lower inner wall 36, widely diverging upper inner wall 38 of accelerating member 40 and horizontally planar lower wall 42 of bonnet member 44. Accelerating member 40 includes a vertically cylindrical lower outer wall 46 engaged with the upper wall 18 of receiving chamber 22. The accelerating member 40 also includes an intermediate planar surface 48 engaged with an upper planar surface 50 of body member 10. An O-ring 52 seals the connection between body member 10 and accelerating member 40. Accelerating member 40 also includes a vertically cylindrical upper outer wall 54 sized more largely than lower outer wall 46. Inner walls 36 and 38 of the accelerating member have circular cross-sections about main axis 24. Upper inner wall 38 asymptotically approaches horizontal as it diverges and extends to an upper edge 56 of upper outer wall 54.
Annular discharge member 58 has equally spaced radial discharge ports 60 extending therethrough from the inner wall 62 thereof. Each discharge port 60 includes a horizontally cylindrical wall 64 defining a discharge orifice 65 in the discharge member inner wall 62. The connection between upper outer wall 54 of accelerating member 40 and inner wall 62 of discharge member 58 is sealed by O-ring 66.
Bonnet member 44 includes a vertically cylindrical lower outer wall 67, which is sealed to inner wall 62 of discharge member 58 by O-ring 68. Bonnet member lower outer wall 67 has the same diameter as upper outer wall 54 of accelerating member 40. Bonnet member planar lower wall 42 is spaced apart from upper edge 56 of accelerating member 40 to form a gap, and the gap is aligned with the discharge orifices 65 of the discharge member 58.
Bonnet member 44 further includes a vertically cylindrical inner wall 70 about main axis 24. Stud 72 is threaded into threads 28 of boss 26 and extends through inner wall 70 of bonnet member 22. Retaining nut 74 is threaded over the end of stud 72 to compressibly mount the bonnet member 44, discharge member 58, accelerating member 40, and screen 32 to the body member 10.
Referring now to FIG. 3, the width of the gap between the lower planar surface 42 of bonnet member 44 and the upper edge 56 of accelerating member 40 is variable by the insertion of spacer washer 80 between accelerating member 40 and discharge member 58 and/or spacer washer 82 between bonnet member 44 and discharge member 58.
In operation, as metered ammonia enters the receiving chamber 22, some of its kinetic energy is destroyed through eddies and friction, etc., while the ammonia retaining its kinetic energy tends to run up the portion of wall 18 opposing the inlet 12. The screen 32 destroys additional kinetic energy and evens out the upward flow of ammonia as it is accelerated upward through the converging portion of the accelerating chamber 34 formed by lower inner wall 36. The ammonia is then further accelerated outward to the discharge ports 60 between the widely diverging upper inner wall 38 of accelerating member 40 and the planar lower wall 42 of bonnet member 44. The resistance of the system downstream from the discharge ports 60 to the soil is small as compared to the resistances of discharge orifices 65, which enhances even distribution. The acceleration of ammonia upward through the accelerating member 40 is a joint effort of all the discharge ports 60. As the ammonia turns outward it is further accelerated and the efflux of the individual discharge ports become effective, and should one discharge port 60 receive ammonia having less mass per unit volume, there would be a velocity increase and, according to Bernoulli's principle, a corresponding pressure drop moving ammonia in its direction. The ability of a discharge port 60 to receive its share of ammonia is related to its efflux volume over the total volume of the outward portion of the accelerating chamber defined by diverging wall 38 and planar wall 42.
In the application of ammonia during the late fall and early spring for corn using large tool bars with wide rows, high outputs, and high tractor speeds, the resistance of the discharge ports 60 will be too great for proper application, so spacer washers 80 and 82 are placed between the discharge member 58 and bonnet member 44 and/or discharge member 58 and accelerating member 40, as shown in FIG. 3, to increase the area of the gap opposite the discharge orifices 65.
The manifold preferably is mounted on a tool bar with retaining nut 74 easily accessible to change the spacer washers 80 and 82, clean the screen 32, or check the interior of the manifold for foreign particles.
Whereas the present invention has been described with respect to a specific embodiment thereof, it will be understood that various changes and modifications will be suggested to one skilled in the art and it is intended to encompass such changes and modifications as fall within the scope of the appended claims. | A manifold for the application of agricultural ammonia includes an acceleraing chamber between an inlet and a plurality of discharge ports. | 1 |
BACKGROUND OF THE INVENTION
This invention relates to high wet modulus fibers having enhanced wet strength and toughness properties so as to be similar in characteristics to cotton.
Some wet modulus fibers of the prior art were found to have certain shortcomings that limited their use. Many were brittle and were subject to fibrillation, and it was also found that these had low abrasion resistance and poor launderability characteristics.
Methods of producing viscose rayon staple from viscose containing a cellulose component of relatively high degree of polymerization are also known. These various known methods are conventionally referred to as "high or intermediate wet modulus fiber," and have some properties close to those of cotton when compared with conventional viscose rayon staple. However, heretofore known high wet modulus fibers still lacked one or more of the preferred properties of cotton such as high alkali resistance, high tensile tenacity and a suitable ratio of wet tenacity to conditioned tenacity. Also, heretofore known methods of production of high wet modulus fiber has been relatively low.
U.S. Pat. No. 2,732,279 of Tachikawa discloses a process for producing a rayon fiber which is stated as being comparable to cotton through the essential features of dissolving cellulose so as to permit the retention of a substantial proportion of intrinsic properties of the natural fiber and with a regeneration procedure which consists of microspinning dissolved cellulose under controlled conditions. However, the total process specifications of Tachiwaka of using a spinning bath of very low acid and low salts results in a fiber which is far from the characteristics of cotton.
U.S. Pat. No. 3,139,467 of Drisch et al carries forward the teachings of Tachiwaka et al in its recognition of the need for a high degree of polymerization (DP) in the fiber. Drisch et al further utilizes the concept of highly stretching the filaments while the fiber is still in the xanthate gel state which requires the utilization of a dilute acid spinning bath with a low salt content. Drisch et al further adds formaldehyde into the dilute bath which, as a result of crosslinking, causes the fiber to have some cotton-like properties but also causes the fiber to be very brittle, which is not at all cotton-like.
U.S. Pat. No. 3,277,226 of Bockno et al and U.S. Pat. No. 3,529,052 of Carney et al. each relate to the development of the so-called high wet modulus fibers, and for the first time there was prepared a synthetic fiber having a cotton-like wet strength, and that approached cotton in low water pick-up and low shrinkage characteristics without being excessively brittle. These fibers and processes were developments in tire cord technology which by virtue of well known viscose additives and high concentrations in the spinning bath of zinc salts yielded a very strong, tough and resilient fiber. The innovations resulted in a fiber with high wet strength, high wet modulus and low shrinkage which added to tire cord toughness and resilience. Nonetheless, these high wet modulus fibers were still somewhat deficient as compared to cotton in water stability and resistance to caustic, which is a good indicator of wet performance.
U.S. Pat. No. 3,434,913 of Bockno et al. and U.S. Pat. No. 3,494,996 of Stevens et al. relate to the preparation of viscose rayon fibers having high strength characteristics and a high wet modulus without being excessively brittle or fibrillatable. However, each of these patents following Drisch disclose the utilization of formaldehyde in the stretch bath which is now known to alter the characteristics of the fiber away from cotton, and introduce other undesirable properties.
With the advent of high wet modulus rayon fibers, toughness and particularly wet performance were substantially improved. High wet modulus rayon became reasonably competitive with cotton in factors including shrinkage, wear resistance, wet performance, and launderability. Accordingly, it was thus possible to place the high wet modulus rayon fibers in many end use fabric applications where rayon had been wholly unsatisfactory before. Examples include sheets and men's shirting fabric. In these applications, the high wet modulus rayon did approximate cotton insofar as wear, abrasion resistance, and launderability characteristics were concerned. For all practical purposes, these high wet modulus (HWM) rayon containing fabrics could withstand a number of launderings without serious deterioration of the fabric.
Nevertheless, cotton still held a real advantage over rayon in the above noted group of properties and also exhibited a decided advantage over rayon in many laboratory tests designed to simulate or predict real fabric performance.
The following Table shows the approximate ratings resulting from various laboratory evaluations of wear by various well known procedures.
TABLE______________________________________ Reg. Rayon HWM Rayon Cotton______________________________________ Untreated Fabric Stoll Flat AbrasionConditioned 85 95 120Wet 20 30 75 Stoll FlexConditioned 110 110 200Wet 85 200 350 Accelerator % Weight LossConditioned 1.7 2.0 3.0Wet 1.5 0.2 0.4 Solubility in 10% NaOH% Dissolved 12% 8% 6%______________________________________
One of the above properties which seems to indicate the toughness of the fiber is that of caustic solubility.
A further qualitative or semi-quantitative evaluation of wear is the appearance of fibrillations along fabric creases. Fibrillation becomes apparent in dyed fabrics and is manifested as a ligher colored fuzz on the fabric surface. This phenomenon appears long before the fabric itself shows a crease or a break. With respect to fabric fibrillation, high wet modulus rayons usually exhibit more fibrillation than do cotton fibers.
It is most important to note that in considering wear evaluation of fibers, fabrics deteriorate far more by washing or cleaning than they do by actual wearing. Accordingly, the behavior of the fiber and fabric in washing machines is more significant than what happens to the fabric while in actual use. By this modern criterion, cotton still has a small but significant advantage over the utilization of conventional rayon and high wet modulus rayon fabrics.
One additional quality which rayon showed at a disadvantage to cotton was in "cover", by which we mean that the same weight of cotton yarn seemed to occupy more volume than its equivalent rayon. By introducing a slight crimp to the rayon, and adding small quantities of delustrants to the rayon, one could make the rayon equivalent to cotton in this quality.
The above noted disadvantages of the utilization of rayon have now been overcome by the creation of a new rayon fiber which is fully equal to cotton in wet toughness, resistance properties and in cover, while maintaining all of the other desirable properties of high wet modulus rayon, namely, high strength conditions, good dyeability, high moisture regain, shrinkage resistance, superior carding properties and the superior spinning and weaving properties of high wet modulus rayon.
SUMMARY OF THE INVENTION
The present invention relates to novel rayon fibers which possess a balance of characteristics and properties which results in a fiber similar to cotton in all of the most important aspects.
In order to obtain the cotton-like rayon fiber of the present invention it is essential to utilize in a spinning step a highly homogeneous spinning solution which is made from cellulose in such a way that the original DP of the pulp used (1,000 or greater) is not reduced to a DP below that of the desired product. In the normal viscose making operation, this would result in a solution of such high viscosity that one would have great difficulty in operations of mixing, filtering, deaerating and pumping through the aging cellars.
It is further critical to achieve a highly homogeneous spinning solution and that the viscose solution be prepared in such a manner as to have little gel reformation. Also, the percentage of cellulose in the viscose solution is important and should be maintained at about from 6.0-9.0%.
In the spinning of the viscose solution, it is essential that a relatively high concentration of zinc salt be present in the coagulation bath along with a proper sulfuric acid concentration. That is, the coagulation bath should contain about 5.0-8.0% sulfuric acid, preferably 6.0-7.0%, and from about 3.0-5.0% of a zinc salt, preferably zinc sulfate.
It has been surprisingly found that where the degree of polymerization of the regenerated cellulose is above 500, the properties of the fiber spun approaches that of natural fiber, even when a spinning bath temperature is maintained at a temperature higher than 30° C.
DETAILED DESCRIPTION OF THE INVENTION
The development of a completely continuous viscose making system, including continuous steeping and mercerization, continuous xanthation and mixing, and continuous filtration and aging, such as disclosed in U.S. Pat. Nos. 4,037,039 and 4,163,840 and copending application Ser. No. 38,068, now U.S. Pat. No. 4,260,739 and incorporated herein by reference, has enabled us to make this new fiber in a practical manner.
In accordance with one embodiment of the present invention, a viscose containing at least 6.0% cellulose is used. The cellulose contained in the viscose should have a DP of at least 500, and preferably 600-700. The viscosity of the viscose at the time of spinning should range between 100 and 1,000 poises. The viscose is spun in a bath comprising about 5.0-8.0% sulfuric acid, and preferably 12-17% sodium sulfate and at least 3.0% zinc sulfate, preferably 3.0-4.0%. The bath can further contain small quantities of a modifying agent such as polyalkylene oxide, but should be free of formaldehyde. The temperature of the bath ranges is preferably between 30° and 40° C. The filaments obtained are stretched in a second hot dilute acid bath, preferably 125-135%.
The viscose compositions and respective spinning conditions are given in the following Examples.
______________________________________ EXAMPLE 1 EXAMPLE 2Viscose Preparation of a Preparation of aComposition: non-crimped fiber crimped fiber______________________________________Wood pulp source 98 98(% alpha cellulose)% cellulose in viscose 7.0 6.0% NaOH 7.0 6.0%CS.sub.2 (Based on 35 32cellulose)DP 600 650Modifiers (based oncellulose) 2% DMA 1% DMA +3% 15 D Phenol +2% 15 D PhenolSalt test 7 to 10 7 to 10______________________________________
If desired, a delustrant material may be added, such as, 0.25-1.0% TiO 2 .
In the viscose making process, it is preferable that, in the steeping step, a high alpha wood pulp or its equivalent is utilized. The preferred conditions for performing the continuous steeping process are as disclosed and claimed in U.S. Pat. No. 4,037,039 and incorporated herein by reference.
Continuous xanthation follows in both the "dry" and slurry steps, followed by a mixing operation, as disclosed in U.S. Pat. No. 4,163,840 of several successive steps of addition of solvent (NaOH and H 2 O), and bringing the xanthate solution to the desired cellulose and NaOH concentrations. If viscose modifiers, such as polyalkylene oxide or dimethylamine, are used they are added in the mixing stage.
The viscose is then passed through a continuous aging, filtration and deaeration operation under controlled conditions to insure the proper ripeness for the spinning operation according to a process such as described in our copending application Ser. No. 89,129 entitled "PROCESS FOR CONTINUOUS FILTRATION AND AGING OF XANTHATED ALKALI CELLULOSE".
A continuous process is particularly essential in working with high viscosity viscose since its production rate is not materially changed when using a more dilute viscose solution which gives lower viscosity at the same D.P. Similarly, higher than customary temperatures should be used to reduce the viscosity with little detrimental effects on non-uniformity.
The standard rayon staple machine may be used to spin the above mentioned viscose solutions, however, it is preferred to use the machine disclosed in copending application Ser. No. 39,866, filed May 17, 1979, which was designed specifically for this type of fiber, because of the uniformity of treatment given every fiber in both spinning and subsequent stretching. Further advantages of this new machine are that of CS 2 and H 2 S recovery, high productivity by spinning with jet clusters and more efficient in the recovery of spent liquor.
Another important feature in the spinning operation for manufacturing the fiber of this invention is the use of a low bath circulation rate, with the overflow from the bath being immediately degassed and filtered before being recycled, as disclosed in said application Ser. No. 39,866. This is desirable from an environmental standpoint and also for the prevention of sulfur compounds (chiefly ZnS) from fouling the bath, jets, guides and acid pipes. The following conditions are preferably used in preparing the filaments of this invention:
______________________________________ EXAMPLE 1 EXAMPLE 2______________________________________A. Spinning Bath Conditions % H.sub.2 SO.sub.4 7.0 6.0 % ZnSO.sub.4 4.0 3.0 % Na.sub.2 SO.sub.4 12.0 17.0 Temperature 30 40 B. Spinning Conditions Speed 35 M/min. 30 M/min. Stretch 135% 125%______________________________________
Following spinning, the continuous filaments are collected in multiple small tows and fed parallel through an enclosed stretch bath, with attendant CS 2 removal and recovery, and stretched under the following conditions:
______________________________________ EXAMPLE 1 EXAMPLE 2______________________________________C. Stretch bath Conditions% H.sub.2 SO.sub.4 2-3% 3.0Temperature °C. 90-100 95-100Washing - first wash acidic.______________________________________
The resultant fiber has the following properties:
EXAMPLE 1
______________________________________ Predicted rangeFiber Properties Broad Narrow Results______________________________________Conditioned strength* 4.5-5.5 5.5-5.25 5.2g/dConditioned 10-20 12-15 12-15Elongation %Wet strength g/d 2.75-3.5 3-3.3 3.2Elongation % 20-30 23-27 25Wet Modulus 6-10 6-8 7-9(g/d at 5% Elong)Caustic solubility 5-7.5 5-7.5 5.0-7.5(% sol. in 10% NaOH)Crimp C.P.I. 0-10 0-10 0- 10Shape round round round______________________________________ *Standard industry test 11% moisture regain strength and elongation.
EXAMPLE 2
______________________________________ Predicted rangeFiber Properties Broad Narrow Results______________________________________Conditioned strength* 4-5 4.3-4.7 4.5(g/d)Conditioned 10-20 12-18 15Elongation (%)Wet strength (g/d) 2.5-3.25 2.8-3.2 3.0Elongation (%) 20-30 23-25 2.3Wet modulus (g/d 7-11 7-9 7-9at 5% elongation)Caustic solubility 5-7.5 5-7.5 5.0-7.5(% sol. in 10%NaOH)Crimp C.P.I. 20-25 20-25 20-25Shape multilobed multilobed multilobed______________________________________ *Standard industry test 11% moisture regain strength and elongation.
Thus, in accordance with the present invention, there is provided a viscose rayon fiber having a degree of polymerization of above about 500, preferably 500-650, an alkali solubility below about 7.5% and a tenacity of about 5-6 g/d.
Additionally, the fiber of the present invention may be crimped or non-crimped and each type with a conditioned strength of 4.0-5.5 g/d with a conditioned elongation of 10-20%. | An improved viscose rayon fiber is disclosed having a degree of polymerization of greater than about 500 and an alkali solubility of below about 7.5%, the fiber also exhibits a tenacity of about 5-6 grams per denier and a conditional elongation of between about 10-20%. This fiber exhibits increased toughness and increased wet strength when compared with prior art rayon fibers. | 3 |
CLAIM OF PRIORITY UNDER 35 U.S.C. §119
The present Application for patent claims priority to Provisional Application No. 60/598,802 entitled “Method and Apparatus for Excess Capacity in a Wireless Network” filed Aug. 3, 2004, and assigned to the assignee hereof and hereby expressly incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field
The present invention relates generally to wireless telephone communications, and specifically to measurement of received signal strength.
2. Background
One of the parameters that is important to determine for efficient operation of a base-station transceiver system (BTS) in a cellular telephone network is the reverse link excess capacity of the BTS. The reverse link excess capacity is measured in terms of a theoretical maximum number of users of the BTS, which in turn is a function of the energy received by the receiving system of the BTS compared with a noise figure of the receiving system. Accurate measurement of this energy difference is difficult to perform.
Methods are known in the cellular network art for determining the noise figure of the receiving system, which is a function of the inherent thermal noise as well as a noise contribution from the receiving system itself. The noise contribution from the receiving system is based on the inherent thermal noise and the gain (or loss) of the elements in the receiving system. For example, the noise contribution of each of the elements in the receiving system at the BTS, from the antenna to the final detector of the system, may be evaluated, and combined with the inherent thermal noise. However, while determination of noise contributions and gain of passive components in the receiving system is relatively straightforward, and the values do not change over time, this is typically not the case for active components. Determination of the noise contribution and gain from active components is usually more complicated and time-consuming; in addition, the noise contribution of active components typically changes over time, and such change may be difficult to predict. Furthermore, and adding to the complication, the noise figure of the receiving system is typically frequency and part dependent, as well as varying with temperature.
Measurement of the energy received by the receiving system at the detector typically suffers from the same problems mentioned above, namely, gain variation with temperature, frequency, and time.
An alternative method for measuring the relative noise level of the receiving system, known in the art, is to arrange that all mobile transceivers transmitting to a BTS are simultaneously silent for a short time period, during which the noise at the BTS may be measured. This method has the advantage, compared to the method described above, of being operable in an active system, at the cost of a reduction of resources during the silent period and the complexity of reacquiring the mobile transceiver signals. In addition, the method suffers from the fact that the BTS can only silence mobile transceivers it controls, and cannot prevent other transmissions from reaching the BTS, unless all BTSs are synchronized and perform the silencing at the same time.
There is thus a need for an improved method for measuring the noise figure of a receiving system in a BTS, for the purposes of measuring the reverse link excess capacity of the BTS.
SUMMARY OF THE INVENTION
In an embodiment of the present invention, a control unit of a base-station transceiver system (BTS) determines a reverse link excess capacity of the BTS. The reverse link excess capacity is typically determined in terms of a number of users that are able to place new calls via reverse link signals to the BTS. The control unit determines the excess capacity by successive measurements of strengths of signals received by a receiving system of the BTS. The control unit analyzes the measurements to find a minimum signal strength received by the receiving system, and the minimum signal strength is used to give an approximate noise level of the receiving system. In calculating the approximate noise level, the control unit periodically adds an “aging value” to the approximate noise level, and then continues its analysis of signal strengths to update the minimum signal strength. Adding the aging value simulates aging, and the consequent rise in noise level, of the receiving system. The reverse link excess capacity of the BTS at any instant may be calculated by comparing the approximate noise level, determined as described above, with the actual received signal measured at the receiving system at that instant.
Using the minimum signal strength as the approximate noise level of the receiving system is a simple and efficient way to estimate the noise of the receiving system. The inventors have found that the results are comparable with those of more complicated, time-consuming, and costly systems for estimating the noise level, and give good results for the determination of the reverse link excess capacity.
There is therefore provided, according to an embodiment of the present invention, a method for estimating a size of reverse link resources provided by a base-station transceiver system (BTS), including:
performing a first measurement of a first signal strength received at the BTS;
performing, subsequent to the first measurement, a second measurement of a second signal strength received at the BTS;
performing, subsequent to the second measurement, a third measurement of a third signal strength received at the BTS;
comparing the first measurement with the second measurement so as to determine an initial minimum signal strength;
adding at a predetermined time an aging value to the initial minimum signal strength so as to form an updated minimum signal strength;
forming a comparison between the updated minimum signal strength and the third measurement;
determining from the comparison a minimum of the updated minimum signal strength and the third measurement to be a minimum received signal strength; and
determining the size of the reverse link resources provided by the BTS in response to the minimum received signal strength.
Typically, the size of the reverse link resources includes a number of channels allocated by the BTS; alternatively or additionally the size of the reverse link resources is substantially equal to a number of users of the BTS.
In one embodiment, determining the size of the reverse link resources includes performing, subsequent to the third measurement, a fourth measurement of a fourth signal strength received at the BTS, and forming a further comparison between the fourth measurement and the minimum received signal strength. Typically, determining the size of the reverse link resources includes determining a reverse link excess capacity of the BTS in response to the further comparison.
In a disclosed embodiment the BTS includes a first receiver and a second receiver, wherein:
performing the first measurement includes performing a first-receiver-first-measurement and a second-receiver-first-measurement of the first signal strength;
performing the second measurement includes performing a first-receiver-second-measurement and a second-receiver-second-measurement of the second signal strength;
performing the third measurement includes performing a first-receiver-third-measurement and a second-receiver-third-measurement of the third signal strength;
wherein comparing the first measurement with the second measurement includes:
comparing the first-receiver-first-measurement with the first-receiver-second-measurement so as to determine a first-receiver-initial-minimum-signal-strength; and
comparing the second-receiver-first-measurement with the second-receiver-second-measurement so as to determine a second-receiver-initial-minimum-signal-strength;
wherein adding at the predetermined time includes:
adding at a first-receiver-predetermined-time a first-receiver-aging-value to the first-receiver-initial-minimum-signal-strength so as to form a first-receiver-updated-updated-minimum-signal-strength; and
adding at a second-receiver-predetermined-time a second-receiver-aging-value to the second-receiver-initial-minimum-signal-strength so as to form a second-receiver-updated-updated-minimum-signal-strength;
wherein forming the comparison includes:
forming a first-receiver-comparison between the first-receiver-updated-updated-minimum-signal-strength and the first-receiver-third-measurement; and
forming a second-receiver-comparison between the second-receiver-updated-updated-minimum-signal-strength and the second-receiver-third-measurement;
wherein determining from the comparison includes:
determining from the first-receiver-comparison a first-receiver-minimum of the first-receiver-updated-updated-minimum-signal-strength and the first-receiver-third-measurement to be a first-receiver-minimum-received-signal-strength; and
determining from the second-receiver-comparison a second-receiver-minimum of the second-receiver-updated-updated-minimum-signal-strength and the second-receiver-third-measurement to be a second-receiver-minimum-received-signal-strength; and
wherein determining the size of the reverse link resources includes determining the size in response to at least one of the first-receiver-minimum-received-signal-strength and the second-receiver-minimum-received-signal-strength.
There is further provided, according to an embodiment of the present invention, apparatus for estimating a size of reverse link resources provided by a base-station transceiver system (BTS), including a control unit which is adapted to:
perform a first measurement of a first signal strength received at the BTS;
perform, subsequent to the first measurement, a second measurement of a second signal strength received at the BTS;
perform, subsequent to the second measurement, a third measurement of a third signal strength received at the BTS;
compare the first measurement with the second measurement so as to determine an initial minimum signal strength;
add at a predetermined time an aging value to the initial minimum signal strength so as to form an updated minimum signal strength;
form a comparison between the updated minimum signal strength and the third measurement;
determine from the comparison a minimum of the updated minimum signal strength and the third measurement to be a minimum received signal strength; and
determine the size of the reverse link resources provided by the BTS in response to the minimum received signal strength.
The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings, a brief description of which is given below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a cellular network system, according to an embodiment of the present invention;
FIG. 2 illustrates a power management relationship, according to an embodiment of the present invention;
FIG. 3 is a schematic graph of a received signal energy vs. a number of users, according to an embodiment of the present invention;
FIG. 4 is a flowchart of a process performed by a control unit in the system of FIG. 1 , according to an embodiment of the present invention; and
FIG. 5 is a flowchart of another process performed by the control unit, according to an embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
Reference is now made to FIG. 1 , which is a schematic diagram of a cellular network system 10 , according to an embodiment of the present invention. Hereinbelow, by way of example, system 10 is assumed to operate as a code division multiple access (CDMA) network. However, the principles of the present invention are not limited to any particular type of network, so that system 10 may be a network operating under any cellular network system known in the art, such as a frequency hopping spread spectrum (FHSS) system, an orthogonal frequency division multiple access (OFDMA) system, or a combination of these and/or CDMA systems and/or other cellular network systems. System 10 comprises one or more base-station transceiver systems (BTSs), only one of which, BTS 18 , is illustrated in FIG. 1 for clarity. BTS 18 is coupled to the rest of network 10 via a base-station controller (BSC) 22 , and a mobile switching center (MSC) 38 .
BTS 18 is operated by a control unit 20 , which is typically physically located at the BTS, although the control unit may be located at any convenient location in system 10 . During the course of operation of BTS 18 , control unit 20 , on a substantially continuous basis, estimates a reverse link excess capacity of the BTS. The method of estimation is described in more detail hereinbelow. Control unit 20 then uses the excess capacity estimation for admission control, wherein the control unit decides if the BTS has sufficient resources to admit a new incoming call, and/or if additional reverse link resources need to be allocated to existing users of the BTS. The resources typically comprise channels which may be operated at different bit rates. In a network where voice comprises the majority of the traffic, each user is typically allocated one channel, so that the number of users and the number of channels allocated by the control unit are substantially equal. In a network where there are other forms of traffic, such as data and/or video transfer, the number of channels is typically larger than the number of users.
BTS 18 operates a sector, herein termed a coverage area 14 , within which generally similar mobile transceivers 12 are able to transmit signals to BTS 18 , and receive signals from the BTS, via one or more antennas coupled to the BTS, the transceivers acting as users of the BTS. Except where otherwise stated below, the following description assumes that BTS 18 has only one antenna 16 . BTS 18 thus comprises a receiving system 24 receiving reverse link signals from the mobiles, and a transmission system 26 transmitting forward link signals to the mobiles. Control unit 20 operates both systems. The transmission system receives forward link signals from BSC 22 at a transmission system input port 34 , and outputs amplified forward link signals from a transmission system output port 36 to antenna 16 .
Receiving system 24 receives signals from antenna 16 at an input receiving system port 30 , and outputs amplified, filtered, and detected signals from an output receiving system port 32 . Receiving system 24 also provides control unit 20 with an indication of the power received by antenna 16 , typically by measuring the levels at one or more detector stages of the receiving system. The indication of the received power at the antenna input, assumed herein to be measured in dBm, is herein termed the received signal strength indication (RSSI_dBm).
To determine the reverse link excess capacity, control unit 20 needs to know the theoretical reverse link capacity of BTS 18 , as well as the reverse link resources that are in use. As is explained in more detail below with reference to FIG. 3 , the theoretical reverse link capacity of the BTS depends on the difference between the strength of the received signals and a noise figure of the receiving system of the BTS.
FIG. 2 illustrates a power management relationship 50 between a number of modules operated by control unit 20 for the determination of the reverse link excess capacity, according to an embodiment of the present invention. A receiver noise figure setting module 52 generates a theoretical value, RX_NOISE, of the noise of receiving system 24 . RX_NOISE is a sum of the thermal noise of the receiving system, substantially determined by the bandwidth and operating temperature of the receiving system, with an estimate of the noise contribution of the components of the receiver system. RX_NOISE may be altered by control unit 20 for purposes of link balancing, as is known in the art. RX_NOISE is transferred to a receive power correction value module 54 , which uses the value of RX_NOISE to determine a corrected value, RSSI_CORRECT_VAL, of RSSI_dBm. The operation of correction value module 54 is described in more detail with respect to FIG. 4 below.
Control unit 20 operates a receive power estimation module 58 to generate the value RSSI_dBm, using, as described above, one or more detected levels in receiving system 24 . Control unit 20 also operates a reverse link excess capacity estimation module 56 to determine an estimate of the excess capacity, using the values of RSSI_dBm, RSSI_CORRECT_VAL, and RX_NOISE.
Other elements of relationship 50 , and shown in FIG. 2 , are described below as required.
FIG. 3 is a schematic graph 70 of a received signal energy at BTS 18 vs. a number of equal-power users, according to an embodiment of the present invention. The horizontal axis of graph 70 shows a theoretical number of users M that are able to transmit to BTS 18 , for a given total energy E received by receiving system 24 of the BTS. Graph 70 is based on the pole capacity equation which is known in the art.
In graph 70 , line 76 determines a maximum theoretical number of equal-power users Mmax in a CDMA system, requiring infinite receive energy at BTS 18 . Typically one would have a reasonable backoff from Mmax to allow for a practical trade-off between the number of users and the receive energy, which in turn contributes to system stability.
In order to implement this backoff, control unit 20 sets a threshold M 70 , which translates into a receive power RSSI_thresh. A typical value for M 70 is 80% of Mmax, which translates to an RSSI_thresh of 7 dB above a receiving system noise energy Nsys. Nsys depends on the thermal noise energy N 0 and the noise generated by the receiving system itself.
While the shape of graphs such as graph 70 is substantially invariant between different receiving systems of different BTSs, its vertical axis intercept Ev depends upon the gain characteristics of the specific receiving system. Thus, as illustrated schematically in FIG. 3 , two other receiving systems may have graphs 72 and 74 , having substantially similar shapes to graph 70 , but each having different vertical axis intercepts, herein termed E 70 , E 72 , and E 74 . A BTS with a measurement offset of the receive energy above Nsys, as characterized by graph 72 or graph 74 , will cause control unit 20 to limit the number of users to M 72 and M 74 instead of the intended value M 70 . For example, for a value M 70 that is 80% of Mmax, a +/−3 dB error in the receive energy above Nsys will result in M 72 and M 74 being 60% and 90% of Mmax respectively.
The Background of the Invention describes some prior art systems for measuring the value of the receive energy above Nsys; in the instant specification we describe a method for estimation of the value of the receive energy above Nsys which does not rely on time-consuming and expensive calibration of the receiving system, or on enforced quiet periods of mobiles transmitting to BTS, such as those used in the prior art. The inventors have found that the method, described in reference to FIG. 4 below, gives good results for the effective estimation of the value of the receive energy above Nsys, and thus for the reverse link excess capacity of BTS 18 , without the drawbacks present in the prior art.
FIG. 4 is a flowchart of a process 90 performed by control unit 20 , according to an embodiment of the present invention. Control unit 20 operates process 90 , in receive power correction value module 54 ( FIG. 2 ), periodically, typically every 20 ms, in order to determine a corrected value, RSSI_CORRECT_VAL, of the RSSI_dBm value output by receiving system 24 . The control unit effectively uses this corrected value as the vertical axis intercept E 70 ( FIG. 3 ).
In an initialization step 92 of process 90 , control unit 20 sets initial values of variables used in the process. Thus, unit 20 initially sets RSSI_CORRECT_VAL to be equal to 0, and the unit sets a range factor RSSI_CORRECT_RANGE, which limits the values of RSSI_CORRECT_VAL output by process 90 to be within a pre-determined range equal to ±RSSI_CORRECT_RANGE; RSSI_CORRECT_RANGE is typically approximately 5 dB. At initialization unit 20 also sets an offset, RSSI_CORRECT_OFFSET, that the unit uses as a correction factor in evaluating RSSI_CORRECT_VAL; RSSI_CORRECT_OFFSET is typically 0 dB. The offset may be set to be non-zero, for example when there is no expectation of a substantially zero load.
In a second step 94 , unit 20 checks if BST 18 has been subject to blossoming or wilting within a preset period. (The terms blossoming and wilting are known in the art, and refer to coming on-line, or going off-line, of a base-station transceiver system.) The preset period is typically of the order of 30 seconds, although any other suitable preset period may be used. If blossoming or wilting have not occurred in the preset period, process 90 continues to a third step 96 ; if they have occurred, the process waits until the preset period has completed before continuing to step 96 .
In step 96 , control unit 20 reads a most recent value of the receiver system received power, RSSI_dBm, and finds the minimum of the most recent value and a previous value of RSSI_dBm. The previous value was read by control unit 20 in a previous time period during which the control unit operated process 90 . The minimum that is determined in step 96 is herein termed RSSI_REF_FILT.
In a fourth step 98 , the corrected value of RSSI_dBm, RSSI_CORRECT_VAL is evaluated by control unit 20 according to equation (1) below. Equation (1) takes the minimum value of step 96 , and uses it to correct the theoretical receiver system noise RX_NOISE.
RSSI _CORRECT — VAL=RX _NOISE−( RSSI — REF — FILT+RSSI _CORRECT_OFFSET) (1)
Also in step 98 , unit 20 verifies that the result of applying equation (1) does not set the value of RSSI_CORRECT_VAL to be outside the range of acceptable values defined by RSSI_CORRECT_RANGE. If equation (1) does give a value outside the range, unit 20 alters the value to be at the appropriate limit of the range.
The value of RSSI_CORRECT_VAL is then transferred to reverse link excess capacity estimation module 56 , which uses the value, as described with reference to FIG. 5 below, to determine the excess capacity of BTS 18 .
In a last step 100 of process 90 , control unit 20 periodically adds an “aging factor” to the evaluated value of RSSI_REF_FILT, according to equation (2) below:
RSSI — REF — FILT=RSSI — REF — FILT+AGE _FACTOR (2)
Control unit 20 typically generates the periodicity, AGE_PERIOD, for applying equation (2), and the value of the aging factor, AGE_FACTOR, in initial step 92 of process 90 . Typical values for AGE_PERIOD and AGE_FACTOR are of the order of 1 hour and approximately 0.1 dB, respectively.
After step 100 , process 90 returns to the beginning of step 94 .
It will be understood from inspection of process 90 that the value RSSI_CORRECT_VAL is a function of the minimum value of RSSI_dBm, determined over the time during which process 90 is operated. It will also be understood that RSSI_CORRECT_VAL approximates the difference between the vertical axis intercept Ev, illustrated in FIG. 3 , and the noise value Nsys of receiving system 24 described above.
The aging factor AGE_FACTOR simulates the change in noise value of receiving system 24 over time, so that the exemplary values given above increase the noise value of the receiving system, with no other change being input to the system, by 0.1 dB every hour. However, it will be understood that this change may be overridden by a smaller actual noise value, RSSI_dBm, received by the receiving system.
FIG. 5 is a flowchart of a process 120 performed by control unit 20 , according to an embodiment of the present invention. Control unit 20 operates process 120 periodically, typically with a period of the order of 20 ms, in reverse link excess capacity estimation module 56 ( FIG. 2 ), to determine a reverse link excess capacity, RL_EXCESS_CAP.
In a first step 122 of process 120 , unit 20 inputs the value of RX_NOISE from setting module 52 , the value of RSSI_dBm from receive power estimation module 58 , and the value of RSSI_CORRECT_VAL, determined by process 90 , from receive power correction module 54 .
In a second step 124 , unit 20 calculates an excess capacity, CRX, for BTS 18 according to an equation (3):
C
RX
=
10
(
RX_NOISE
-
(
RSSI_dBm
+
RSSI_CORRECT
_VAL
)
)
10
(
3
)
Typically, the value of CRX is approximately 0.5 (corresponding to a loading of 50%) or approximately 0.25 (corresponding to a loading of 75%), since lower values of CRX, corresponding to higher loading values, may lead to transmitted traffic being perceived to be of sub-optimal quality.
In a final step 126 , unit 20 ensures that the calculated value of RL_EXCESS_CAP is within limits of 0% and 100% by applying a limiting equation (4) to the excess value CRX determined in step 128 .
RL _EXCESS — CAP =min( C RX ;1)×100% (4)
Returning to FIG. 1 , antenna 16 may comprise two or more antennas, which each have separate and generally similar receiving systems 24 . In this case, by using a process of diversity known in the art, signal reception in the sector corresponding to area 14 may be improved compared to reception using a single antenna.
In the case of two or more antennas 16 , the processes described above may be applied separately to each receiving system of the respective antennas, to estimate a reverse link excess capacity for each of the systems. Typically, the estimation that is used may then be based on the worst of the estimates, or on an average of some or all of the different receiving system estimates. Since the receiving systems are distinct systems, control unit 20 may use the same or different initial values of variables, such as AGE_FACTOR and/or AGE_PERIOD, for each receiving system in implementing the processes described above.
It will be appreciated that the embodiments described above are cited by way of example, and that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing the foregoing description and which are not disclosed in the prior art. | A method for estimating a size of reverse link resources provided by a base-station transceiver system (BTS), including performing respective first, second, and third measurements of first, second, and third signal strengths received at the BTS. The method also includes comparing the first measurement with the second measurement so as to determine an initial minimum signal strength, and adding at a predetermined time an aging value to the initial minimum signal strength so as to from an updated minimum signal strength. The method further includes forming a comparison between the updated minimum signal strength and the third measurement, determining from the comparison a minimum of the updated minimum signal strength and the third measurement to be a minimum received signal strength, and determining the size of the reverse link resources provided by the BTS in response to the minimum received signal strength. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 14/463,928 filed Aug. 20, 2014, which is a non-provisional of U.S. Application No. 61/868,885, filed Aug. 22, 2013, the contents of which are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] This application relates to gas phase synthesis of nanoparticle-based materials. More particularly, but not exclusively, it relates to down-converting light from a light emitting diode (LED) by synthesizing QDs within pores etched into the LED.
BACKGROUND
[0003] There has been substantial interest in exploiting compound semiconductors having particle dimensions on the order of 2-50 nm, often referred to as quantum dots (QDs), nanoparticles, and/or nanocrystals. These materials have high commercial interest due to their size-tunable electronic properties, which can be exploited in a broad range of commercial applications. Such applications include optical and electronic devices, biological labeling, photovoltaics, catalysis, biological imaging, light emitting diodes (LEDs), general space lighting, and electroluminescent displays.
[0004] Well-known QDs are nanoparticles of metal chalcogenides (e.g, CdSe or ZnS). Less studied nanoparticles include III-V materials, such as InP, and including compositionally graded and alloyed dots. QDs typically range from 2 to 10 nanometers in diameter (about the width of 50 atoms), but may be larger, for example up to about 100 nanometers. Because of their small size, QDs display unique optical and electrical properties that are different in character to those of the corresponding bulk material. The most immediately apparent optical property is the emission of photons under excitation. The wavelength of these photon emissions depends on the size of the QD.
[0005] The ability to precisely control QD size enables a manufacturer to determine the wavelength of its emission, which in turn determines the color of light the human eye perceives. QDs may therefore be “tuned” during production to emit a desired light color. The ability to control or “tune” the emission from the QD by changing its core size is called the “size quantization effect”. The smaller the QD, the higher the energy, i.e. the more “blue” its emission. Likewise, larger QDs emit light more toward the electromagnetic spectrum's red end. QDs may even be tuned beyond visible spectrum, into the infrared or ultra-violet bands. Once synthesized, QDs are typically either in powder or solution form.
[0006] A particularly attractive application for QDs is in the development of next generation LEDs. LEDs are becoming increasingly important in modern day life and it's predicted that they have the potential to become a major target for QD applications. QDs can enhance LEDs in a number of areas, including automobile lighting, traffic signals, general lighting, liquid crystal display (LCD) backlight units (BLUs), and display screens.
[0007] Currently, LED devices are typically made from inorganic solid-state compound semiconductors, such as GaN (blue), AlGaAs (red), AlGaInP (orange-yellow-green), and AlGaInN (green-blue). Each of these materials emit a single color of light, as indicated. As white light is a mixture of colors in the spectrum, solid-state LEDs that emit white light cannot be produced using a single solid-state material. Moreover, it is difficult to produce “pure” colors by combining solid-state LEDs that emit at different frequencies. At present, the primary method of producing white light or a mixture of colors from a single LED is to “down-convert” light emitted from the LED using a phosphorescent material on top of the solid-state LED. In such a configuration, the light from the LED (the “primary light”) is absorbed by the phosphorescent material and re-emitted at a second, lower frequency (the “secondary light”). In other words, the phosphorescent materials down-converts the primary light to secondary light. The total light emitted from the system is a combination of the primary and secondary light. White LEDs produced by phosphor down-conversion cost less and are simpler to fabricate than combinations of solid-state red-green-blue LEDs. Unfortunately, however, conventional phosphor technology produces light with poor color rendering (i.e. a color rendering index (CRI)<75).
[0008] QDs are a promising alternative to conventional phosphor technology. Their emission wavelength can be tuned by manipulating nanoparticle size. Also, so long as the QDs are monodispersed, they exhibit strong absorption properties, narrow emission bandwidth, and low scattering. Rudimentary QD-based light-emitting devices have been manufactured by embedding coloidally produced QDs in an optically transparent (or sufficiently transparent) LED encapsulation medium, such a silicone or an acrylate, which is then placed on top of a solid-state LED. Thus, the light produced from the LED package is a combination of the LED primary light and the secondary light emitted from the QD material.
[0009] However, such systems are complicated by the nature of current LED encapsulants. For example, QDs can agglomerate when formulated into current LED encapsulants, thereby reducing their optical performance. Furthermore, even after the QDs have been incorporated into the LED encapsulant, oxygen can still migrate through the encapsulant to the surfaces of the QDs, which can lead to photo-oxidation and, as a result, a drop in quantum yield (QY).
[0010] Thus, there is need in the art for a fast and inexpensive method that can reliably down-convert an LED.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The foregoing summary, as well as the following detailed description, will be better understood when read in conjunction with the appended drawings. For the purpose of illustration only, there is shown in the drawings certain embodiments. It's understood, however, that the inventive concepts disclosed herein are not limited to the precise arrangements and instrumentalities shown in the figures.
[0012] FIGS. 1A-1C illustrate pores etched into a semiconductor material.
[0013] FIG. 2 shows the formation of QDs within pores of a semiconductor material from gaseous precursors provided with counter current gas streams.
[0014] FIG. 3 shows the formation of QDs within pores of a semiconductor material from gaseous precursors provided with parallel gas streams.
[0015] FIG. 4 illustrates an apparatus for providing counter-current flow of QD precursor gases.
[0016] FIG. 5 illustrates an apparatus for providing parallel flow of QD precursor gases.
[0017] FIG. 6 is a diagram comparing the relative size of an oxygen molecule to gas-phase precursor molecules of QDs.
[0018] FIGS. 7A-7C illustrate the formation of QDs within pores selectively etched into a semiconductor material.
[0019] FIG. 8 illustrates a conventional LED having nanoparticles embedded within a porous n-GaN layer.
DESCRIPTION
[0020] It should be understood that the inventive concepts set forth herein are not limited in their application to the construction details or component arrangements set forth in the following description or illustrated in the drawings. It should also be understood that the phraseology and terminology employed herein are merely for descriptive purposes and should not be considered limiting. It should further be understood that any one of the described features may be used separately or in combination with other features. Other invented systems, methods, features, and advantages will be or become apparent to one with skill in the art upon examining the drawings and the detailed description herein. It is intended that all such additional systems, methods, features, and advantages be protected by the accompanying claims.
[0021] The present disclosure generally relates to light emitting devices using a solid-state LED material into which pores have been etched. QDs are synthesized within those pores. When the LED material emits light (i.e., primary light) the QDs absorb some of that light and reemit light having a color determined by the size of the QDs (i.e., secondary light). The light emitted from the light-emitting device therefore includes a combination of the primary and secondary light. Various combinations of LED materials and QD materials and sizes can be used to obtain white light or to obtain other blends of light.
[0022] According to some embodiments, the QD materials are synthesized within the pores of the LED material via gas phase reactions. As explained in more detail below, the gas phase QD precursor material diffuse into the pores of the LED material where they react to form QDs. The size of the QDs may be limited by the size of the pores in which the QDs form. In this way, the pores may be thought of as providing a “template” for QD formation. Since the color of light that a QD emits depends on the size of the QD, the color of emitted light can be tuned by controlling the size of the pores in which the QDs form.
[0023] Generally, any solid-state LED semiconductor material can be used. Examples include, but are not restricted to, inorganic solid-state compound semiconductors, such as GaN (blue), AlGaAs (red), AlGaInP (orange-yellow-green), AlGaInN (green-blue), or any derivatives thereof. The characteristic emission colors of each material are provided in parentheses. The examples discussed in this disclosure primarily concern GaN, as it is common to seek to down-convert light from blue-emitting GaN.
[0024] Pores can be etched in the solid-state LED semiconductor material using any means known in the art. Examples of controlled etching are contained in Cuong Dang et al., A wavelength engineered emitter incorporating CdSe - based colloidal quantum dots into nanoporous InGaN/GaN multiple quantum well matrix , Phys. Status Solidi, No. 7-8, 2337-339 (2011); Dang et al., A wafer - level integrated white - light - emitting diode incorporating colloidal quantum dots as a nanocomposite luminescent material , Adv. Materials, No. 24, 5915-18 (2012); and Chen et al., High reflectance membrane - based distributed Bragg reflectors for GaN photonics , App. Phys. Lett., No. 101, 221104 (2012). The reader is referred to those references for details concerning the etching of the LED semiconductor material. Generally, the LED semiconductor material is etched using an electrochemical method, for example, anodic etching in an oxalic acid electrolyte. The pore size and concentration can be controlled as a function of the applied voltage. Other methods of etching, such as acid etching and/or inductively coupled plasma-reactive ion (ICP-RI) etching may be used. It is found that the etching technique does not impair the semiconductor material's carrier transport and recombination capability. FIGS. 1A-1B , by way of example only, illustrate semiconductor materials having etched pores.
[0025] In some embodiments, the etching technique produces pores having approximately the same diameter. For example, referring to FIG. 1A , the pores 100 can be etched to a target pore size. In one embodiment, the target pore size may be between approximately 2 nm and 10 nm. The pore size can be tuned to a uniform diameter that accommodates growth of both red-emitting QDs and green-emitting QDs. For example, the pore size can be tuned to a single diameter that accommodates growth of red-emitting Group III-V based QDs (e.g. InP, and including graded dots and alloys), and green-emitting CdSe QDs. In one embodiment, a semiconductor material for a blue-LED (e.g., GaN) is selectively etched as in FIG. 1A to accommodate growth of both red and green QDs at a level that effectively down-converts the LED to produce white light emissions.
[0026] Alternatively, the semiconductor material can be selectively etched to include pores of various sizes, as shown in FIG. 1B, 110, 120 . For example, a semiconductor material for a blue-LED (e.g., GaN) can be selectively etched as in FIG. 1B to accommodate growth of both red and green QDs at a level that effectively down-converts the LED to produce white light emissions.
[0027] In other embodiments, as illustrated in FIG. 1C , the etching technique produces pores 130 having a small diameter on the top side of a semiconductor material, and pores 140 having a large diameter on the bottom side of the semiconductor material. For example, the bottom side of the semiconductor material can be etched first to a target depth (e.g., halfway) and pore size (e.g., larger diameter). Etching time can control the pore depth, while changing the bias voltage can control the pore size. After etching large pores 140 into the bottom layer, the semiconductor material can be turned over, and small pores 130 can be selectively etched in the top layer to a target depth (e.g., halfway) and pore size (e.g., smaller diameter). Again, etching time and bias voltage can be used to control pore depth and size. According to some embodiments, the small diameter pores 130 are etched to a size that can accommodate growth of green QDs and the large diameter pores 140 are etched to a size that can accommodate growth of red QDs. This pore architecture positions the red QDs below the green QDs to prevent reabsorption of the secondary light emitted by the QDs. In one embodiment, a semiconductor material for a blue-LED (e.g., GaN) is selectively etched as in FIG. 1C to accommodate growth of both red and green QDs at a level that effectively down-converts the LED light to produce white light.
[0028] Once the LED semiconductor material is etched to provide pores, QDs are formed within those pores by reacting gas phase QD precursor compounds together within the pores. The precursors may be used to synthesize QDs including, but not restricted to, the following materials: Group II-VI nanoparticles (e.g., CdS, CdSe, ZnS, ZnSe), Group III-V nanoparticles (e.g., InP, GaP), Group II-V nanoparticles (e.g., Cd 3 P 2 ), and Group III-VI nanoparticles (e.g., In 2 Se 3 ). In one embodiment, suitable gas-phase precursors may include, but are not restricted to, a Group II or Group III cation source, (e.g., R 2 Cd/Zn; R 3 Ga/In (R=organic group)), and a Group V or Group VI anion source, (e.g., H 2 S, H 2 Se or H 3 P). In yet another embodiment, the flow rate of the gas-phase precursors may be controlled using a carrier gas. The carrier gas may include, but is not limited to, an inert gas (e.g., He, N 2 or Ar), or a reducing gas (e.g., H 2 ).
[0029] The pores in the semiconductor material allow the gas phase precursors to diffuse throughout the material. The nucleation and growth of QDs from gaseous precursors may proceed in any pores. Furthermore, since QD stability increases with particle size, under suitable reaction conditions particle growth may continue until all the space is occupied. Therefore, the size of the nanoparticles can be restricted by the pore diameter. By way of example only, QDs having an approximately 5 nm diameter can form in approximately 5 nm pores. In one embodiment, QDs having uniform dimensions can grow in the pores. In another embodiment, QDs having variable diameters grow in the pores. In one embodiment, both red and green QDs grow in the pores of a semiconductor material for a blue-LED (e.g., GaN) at a level that effectively down-converts the LED to produce white light emissions. The resulting material is free of liquid solvents because the QD-producing reactions involve only gas phase precursors.
[0030] QDs may be prepared by the reaction of gas phase QD precursors as described in N. L. Pickett et al., in J. Mater. Chem., 1997, 7, 1855 and in J. Mater. Chem., 1996, 6, 507. The size of the resultant QDs may be varied by careful control of the reaction conditions (e.g., temperature, time, etc.), and the addition of pyridine in the gas phase. Likewise, the methods used to synthesize QDs in polymer matrices described by Haggata et al. S. W. Haggata et al., J. Mater. Chem., 1996, 6, 1771 and J. Mater. Chem., 1997, 7, 1996 may be adapted to synthesize QDs in the pores of the LED semiconductor material. The Pickett and Haggata references cited in this paragraph are hereby incorporated by reference in their entirety.
[0031] Generally, the gas phase QD precursors are exposed to the pores in parallel or counter flow and allowed to react within the pores. In one embodiment, the pores have variable sizes to accommodate both red and green QD growth. In another embodiment, the reaction conditions are controlled to produce both red and green QDs. In yet another embodiment, the QDs may be formed in the semiconductor material at a level that effectively down-converts the semiconductor material to produce white light emissions.
[0032] Gas phase reaction conditions can be used to control QD growth within the semiconductor material. For example, pyridine and higher temperatures may be used to inhibit nanoparticle growth as reported by Pickett et al., Effect of pyridine upon gas - phase reactions between H 2 S and Me 2 Cd; control of nanoparticle growth , J. Mater. Chem., No. 6, 507-09 (1996). Thus, in one embodiment, the gas-phase synthesis can be carried out in the presence of a Lewis base in the gas phase. For example, the Lewis base can coordinate to the surface of the QDs and control their size. Higher concentrations of a Lewis base can be used to synthesize smaller QDs. Suitable Lewis bases may include, but are not restricted to, pyridine gas. In still another embodiment, the semiconductor may comprise a material that may act as a Lewis base. In another embodiment, the reaction may be carried out at a certain temperature. Suitable temperatures may include, but are not restricted to, approximately 25° C. to 200° C. Higher temperatures can be used to produce smaller QDs. In still another embodiment, a Lewis base concentration and temperature are adjusted during gas-phase synthesis in order to synthesize different size QDs within the semiconductor material. In one embodiment, the Lewis base concentration and temperature can be selectively adjusted to a level that results in synthesis of both red and green QDs within the pores of a semiconductor material for a blue-LED (e.g., GaN) at a level that effectively down-converts the LED to produce white light emissions.
[0033] In an alternative embodiment, QDs having same size but different wavelength emissions can be grown within the pores of a semiconductor material. For example, nanoparticle precursors can be selected to grow both Group III-V based QDs (e.g. InP, and including graded dots and alloys) and CdSe QDs. InP QDs emitting at a particular wavelength are relatively smaller than CdSe QDs emitting at the same wavelength. Thus, in an embodiment, InP and CdSe QDs can grow to the same size but emit different wavelengths. In one embodiment, the InP and CdSe QDs grow within pores having uniform diameter, wherein the InP QDs emit red light and the CdSe QDs emit green light. In an embodiment, the concentration of precursors for red-emitting QDs and green-emitting QDs can be selectively adjusted to a level that results in synthesis of both red and green QDs within the pores of a semiconductor material for a blue-LED (e.g., GaN) at a level that effectively down-converts the LED to produce white light emissions.
[0034] In one embodiment, a porous semiconductor material 200 is placed in the middle of two streams of gas flowing from opposite directions, 201 and 202 , respectively, as illustrated in FIG. 2 . The gas streams can include precursors to QDs 204 . Referring to FIG. 2 , as the gas streams flows through the semiconductor material 200 , nanoparticle nucleation and growth may ensue in the material's pores 203 . Nanoparticle sizes can be restricted by the size of the pores 203 they grow in. In an alternative embodiment, nanoparticle sizes may be restricted by reaction conditions, including adjustment to Lewis base concentration and/or temperature. In an embodiment, the precursor gas streams flow in an alternating pattern. In another embodiment, the precursor gas streams flow simultaneously.
[0035] In another embodiment, a porous semiconductor material 300 is placed in the stream of two parallel gas sources 301 , 302 , as illustrated in FIG. 3A . The gas streams may be allowed to flow either sequentially or in tandem. As in the method described in FIG. 2 , the gas streams can include precursors to QDs 304 . As illustrated in FIG. 3 , as the gas streams flow through the semiconductor material 300 , nanoparticle nucleation and growth may ensue in the material's pores 303 . Again, nanoparticle sizes can be restricted by the size of the pores 303 they grow in. In an alternative embodiment, nanoparticle sizes may be restricted by reaction conditions, including adjustment to Lewis base concentration and/or temperature. In an embodiment, the precursor gas streams flow in an alternating pattern. In another embodiment, the precursor gas streams flow simultaneously.
[0036] FIGS. 4 and 5 illustrate embodiments of apparatuses for the gas-phase synthesis of QDs. In the apparatus 400 illustrated in FIG. 4A , a semiconductor material 401 is inserted into a quartz tube 402 , which is then positioned in a tube furnace 403 . QD precursor gasses are provided by lines 404 and 405 to opposite sides of the semiconductor material. The gas streams can flow simultaneously or in an alternating pattern. For example, line 404 may provide a gas phase QD precursor such as H 2 S, H 2 Se, or PH 3 , and line 405 may provide a QD precursor such as R 2 Zn, R 2 Cd, R 3 Ga or R 3 In. Apparatus 400 can also include lines 406 and 407 for carrier gasses. Apparatus 400 may also include a source 408 for providing a Lewis base. Precursor gas lines may include a reactor 409 for generating gaseous precursors. Any or all of the gas lines may be provided with gas-flow meters 410 and 411 . Exhaust lines 412 and 413 may be provided with scrubbers 414 and 415 , respectively, and with pressure controllers 416 and 417 respectively.
[0037] In the apparatus 500 illustrated in FIG. 5 , a semiconductor material 501 is positioned into a quartz tube 502 , which is positioned in tube furnace 503 . The semiconductor material is exposed to parallel streams of QD precursor gas provided by lines 504 and 505 . The gas streams can flow simultaneously or in an alternating pattern. The apparatus may also include one or more lines 506 providing additional reagents, such as a Lewis base. Lines 504 and 505 are connected to sources of QD precursor gasses 507 and 508 , respectively. In apparatus 500 , line 506 can be connected to a source of Lewis base 509 . As in the apparatus illustrated in FIG. 4 , example precursor gasses for apparatus 500 include H 2 S, H 2 Se, or PH 3 , and R 2 Zn, R 2 Cd, R 3 Ga or R 3 In. Any of the gas lines can also be provided with a source of carrier gas 510 and additional equipment, such as gas-flow meters 511 and 512 . Quartz tube 502 may contain glass wool 513 up stream of exhaust line 514 . Exhaust line 514 may be equipped with monitoring, control, or processing equipment, such as one or more scrubbers 515 and pressure controller 516 .
[0038] The particular set-ups illustrated in FIGS. 4 and 5 are exemplary and schematic only. It will be readily apparent to one of skill in the art how to implement these and other geometries for providing QD precursor gasses to a semiconductor material, as described herein. The scope of the invention is not limited to any particular reactor geometry or apparatus.
[0039] The methods and apparatuses described herein can grow QDs within a semiconductor material because gas phase QD precursors can diffuse into nano-size pores and react inside those pores. FIG. 6 compares the relative size of QD precursor molecules Me 2 Cd 601 , Me 2 Zn 602 , H 2 S 603 , H 2 Se 604 , PH 3 605 , and InMe 3 606 to the size of O 2 600 .
[0040] FIGS. 7A-7C illustrate the formation of QDs within pores selectively etched into a semiconductor material 700 . Gaseous QD precursors can diffuse into pores as small as 1 nm in width or less. The QD precursors react within the pores to form QDs 702 . In wider pores 703 , the precursors react to form larger diameter QDs 702 a . In one embodiment, these larger diameter QDs 702 a can emit light that is red-shifted. In narrower pores 704 , smaller diameter QDs 702 b can form. In another embodiment, these smaller QDs 702 b can emit green-shifted light.
[0041] Referring to FIG. 7A , QDs can be grown in a semiconductor material 700 having pores with uniform diameter 710 ( FIG. 1A ). In another embodiment, as illustrated in FIG. 7B , QDs can be grown in a semiconductor material 700 having pores with different diameters 740 , 750 ( FIG. 1B ). In still another embodiment, as illustrated in FIG. 7C , QDs can be grown in a semiconductor material 700 having pores with a small diameter 770 in the top half of the semiconductor material and a large diameter 780 in the bottom half of the semiconductor material ( FIG. 1C ).
[0042] The QD precursors can diffuse into the pores and grow to a size that fills the diameter of the pores. In one embodiment, the gaseous precursors include nanoparticle precursors to produce both red 720 and green QDs 730 within the uniform-sized pores. For example, the gas may include precursors for Group III-V based QDs (e.g. InP, and including graded dots and alloys) and CdSe QDs, which will emit different wavelengths at a certain size. In an alternative embodiment, adjusting Lewis base concentration and/or temperature during synthesis can be used to selectively control QD size. In one embodiment, reaction conditions are controlled to grow red-emitting QDs 720 in the bottom half of the semiconductor material, and green-emitting QDs 730 in the top half of the semiconductor material. In yet another embodiment, green and red-emitting QDs are grown within a blue-light emitting semiconductor material having uniform pore diameter at a level that effectively down converts the semiconductor material to white light emissions.
[0043] In yet another embodiment, as illustrated in FIG. 8 , a conventional LED can include a selectively etched n-GaN layer with nanoparticles embedded in its pores. The LED may include a Sapphire Substrate 801 , an n-GaN layer 802 , a p-n junction active layer 803 , a p-GaN layer 804 , a p-electrode 805 , and an n-electrode 806 . In one embodiment, both green 807 and red-emitting QDs 808 can be embedded in the n-GaN pores. In another embodiment, green-emitting QDs 807 are embedded in the top half 809 of the n-GaN layer and red-emitting QDs 808 are embedded in the bottom half 810 of the n-GaN layer. Any of these designs can be achieved with one or more of the aforementioned methods. In still another embodiment, the QDs are embedded in the n-GaN layer with a design and at a level that results in down-converting the LED to a substantially white light emission 811 .
[0044] The present application presents numerous advantages over the prior art. It relies on gaseous precursors, which though larger than individual oxygen and water molecules, are of the same order of magnitude. As illustrated in FIG. 6 , the gaseous precursors suggested herein are less than three times the length of an oxygen molecule (˜3 Å) along their longest axis, which enables them to diffuse into pores less than 1 nm in diameter, i.e. below the lower limit for QD stability. As shown in FIGS. 7A-7C , if a pore is large enough such that it corresponds to a diameter within the stable QD range, nanoparticle formation may proceed. Furthermore, gaseous precursors are able to penetrate the entire semiconductor material layer. And unlike prior art techniques such as high pressure nitrogen adsorption, the embodiments herein do not assume and rely on cylindrical pores. The techniques herein can be used to formulate QDs in any pore shape. Furthermore, with the methods and apparatuses described herein, cryogenic temperatures, which may be damaging to LEDs and may be challenging and costly to maintain, are not required. Moreover, the semiconductor need not be exposed to potentially damaging high pressures. Consequently, the method does not introduce defects into the semiconductor material during gas-phase synthesis. Furthermore, since the nanoparticle size may be controlled by a number of parameters, including temperature, time, carrier gas, and the concentration of an optional Lewis base, the technique may be adapted for use with a wide range of semiconductor materials, including those used in LEDs.
[0045] It's understood that the above description is intended to be illustrative, and not restrictive. The material has been presented to enable any person skilled in the art to make and use the inventive concepts described herein, and is provided in the context of particular embodiments, variations of which will be readily apparent to those skilled in the art (e.g., some of the disclosed embodiments may be used in combination with each other). Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention therefore should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.”
EXAMPLES
Example 1: CdS
[0046] CdS QDs may be formed from the gas phase reaction of helium gas streams containing Me 2 Cd and H 2 S in the presence of pyridine gas. Typical reaction conditions include a He flow rate of ˜600 cm 3 min −1 and a 30-fold excess of H 2 S to Me 2 Cd. The particle size may be controlled by varying the pyridine concentration and/or the reaction temperature. Preferably, pyridine:Me 2 Cd ratios in the range 1:20 to 2:1, and temperatures between room temperature and 200° C. are employed. It has been found that increasing the pyridine concentration reduces the particle size, while the particle size increases with increasing temperature.
[0047] The absorption of the CdS nanoparticles may be tuned from the UV to cyan (bulk band gap ˜512 nm) depending on the particle size. For example, nanoparticles in the size range 2-20 nm may be expected to emit between approximately 320-500 nm, corresponding with UV to cyan light.
Example 2: CdSe
[0048] Reaction conditions similar to those outlined for CdS (above) may be used to synthesize CdSe QDs [N. L. Pickett et al., J. Mater. Chem., 1997, 7, 1855], substituting H 2 S for H 2 Se. Higher pyridine concentrations may be used to control the particle size (up to 150:1 pyridine:Me 2 Cd).
[0049] The absorption of the CdSe nanoparticles may be tuned from the blue to the deep red (bulk band gap ˜717 nm) depending on the particle size. Nanoparticles in the size range 2-20 nm may be expected to emit between approximately 490-700 nm, corresponding with blue to deep red light.
Example 3: ZnS
[0050] Reaction conditions similar to those outlined for CdS (above) may be used to synthesize ZnS QDs [N. L. Pickett et al., J. Mater. Chem., 1997, 7, 1855], substituting Me 2 Cd for Me 2 Zn. Higher reaction temperatures (up to 300° C.) may be advantageous.
[0051] The absorption of the ZnS nanoparticles may be tuned across the UV spectrum (bulk band gap ˜344 nm) depending on the particle size. Nanoparticles in the size range 2-20 nm may be expected to emit between approximately 235-340 nm.
Example 4: ZnSe
[0052] Reaction conditions similar to those outlined for ZnS (above) may be used to synthesize ZnSe QDs [N. L. Pickett et al., J. Mater. Chem., 1997, 7, 1855], substituting H 2 S for H 2 Se. A reducing H 2 carrier gas, rather than inert He, may be more effective at controlling the particle size.
[0053] The absorption of the ZnS nanoparticles may be tuned from the UV to the blue (bulk band gap ˜459 nm) depending on the particle size. Nanoparticles in the size range 2-20 nm may be expected to emit between approximately 295-455 nm, corresponding with UV to indigo light.
Example 5: InP
[0054] InP nanoparticles may be synthesized using a reaction procedure similar to those outlined for II-VI QDs (above) from Me 3 In and PH 3 gaseous precursors.
[0055] The absorption of the InP nanoparticles may be tuned from the green to the near-IR (bulk band gap ˜925 nm) depending on the particle size. Nanoparticles in the size range 2-20 nm may be expected to emit between approximately 520-875 nm, corresponding with green light to IR radiation. | Light-emitting materials are made from a porous light-emitting semiconductor having quantum dots (QDs) disposed within the pores. According to some embodiments, the QDs have diameters that are essentially equal in size to the width of the pores. The QDs are formed in the pores by exposing the porous semiconductor to gaseous QD precursor compounds, which react within the pores to yield QDs. According to certain embodiments, the pore size limits the size of the QDs produced by the gas-phase reactions. The QDs absorb light emitted by the light-emitting semiconductor material and reemit light at a longer wavelength than the absorbed light, thereby “down-converting” light from the semiconductor material. | 2 |
FIELD OF THE INVENTION
The present invention relates to cooling systems for a stern drive.
BACKGROUND OF THE INVENTION
As is conventionally known, a stern drive (also referred to as an inboard engine—outboard drive) includes an engine provided inboard, and a drive unit provided outboard that transmits power from the engine to a propeller. Further, a cooling system for such a stern drive is also conventionally known. Such a cooling system cools the drive unit by spraying water onto a housing of the drive unit. The water is taken from ambient water of the drive unit, and the water is discharged using water pressure generated by the propulsive speed due to the so-called ram effect.
For example, U.S. Pat. No. 6,808,432, which was issued to Richard A. Davis et al. on Oct. 26, 2004, teaches providing a cover to a housing of a drive unit, and using a cooling unit that discharges water through an outlet on the top of the housing where a gear that generates heat is contained, using ram pressure. However, this cooling system has the following defect. A general housing contains oil to be used as a lubricating oil, or as a hydraulic fluid for operating the hydraulic clutch when a hydraulic clutch is provided. The oil level is enough to soak the gear in the housing, and the space between the oil level and the internal top of the housing has low heat conductivity. In other words, this space serves as a heat insulator. Therefore, the cooling system disclosed in U.S. Pat. No. 6,808,432 does not ensure desirable cooling efficiency.
U.S. Pat. No. 5,871,380, which was issued to Dean Claussen on Feb. 16, 1999, teaches an intercooler for a stern drive using a water jacket, which is provided on the back of the housing, where a gear that generates heat is provided.
However, in this invention, water accumulates in the water jacket, increasing the water pressure inside the water jacket. This inhibits the ram effect. This invention also, therefore, does not ensure desirable cooling efficiency.
SUMMARY OF INVENTION
Therefore, it is the main object of the present invention to provide a cooling system for a stern drive with improved cooling efficiency.
A cooling system for a stern drive, according to a preferred embodiment of the present invention, comprises: a conduit having a water outlet for discharging ambient water, which is introduced by using a water current generated by the propulsion of a boat to which said stern drive is mounted, the water outlet being directed toward a side wall of a housing containing a gear and a clutch where heat is generated, to a location near the gear and the clutch; and a cover removably attachable to the housing, the conduit being contained between the cover and the housing, the cover defining a space to which water is discharged from the water outlet and a drain section for draining the water.
The water outlet may be directed substantially horizontally, in a direction along the side wall of the housing.
The water outlet may be located at a level close to the top of the clutch in the housing.
The cooling system according to the present invention may further comprise a protruding portion for increasing a heat removing effect by the water discharge from the water outlet, the protruding portion being provided at a level lower than the water outlet provided at the location of the side wall of the housing.
The protruding portion may include a rib, which is provided on the side wall of the housing and extends across the side wall.
The protruding portion may include a periphery wall section, which serves as a periphery wall of an observation window for visually confirming an oil level inside the housing, the periphery wall section being protruding from the side wall of the housing.
The drain section may include a gap between an edge of the cover and the housing.
A water outlet is preferably provided on each of a right side wall and a left side wall of the housing.
It is preferable that the cooling system according to the present invention further comprise a boss protruding from the side wall to fix the cover to the side wall of the housing with a bolt, and the height of the conduit is no higher than the protruding height of the boss.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention are described below with reference to drawings.
FIG. 1 is a lateral view illustrating a stern drive incorporating a desirable embodiment of the cooling system according to the present invention, and a part of a boat having the stern drive.
FIG. 2 is a lateral view illustrating an internal structure of a part of the stern drive of FIG. 1 .
FIG. 3 is a perspective view illustrating a part of the stern drive of FIG. 1 without a cover.
FIG. 4 is a lateral view illustrating a part of an uncovered drive unit of the stern drive of FIG. 1 .
FIG. 5 is a cross-sectional view, taken along the line V-V of FIG. 1 .
FIG. 6 is a cross-sectional view showing a magnified view of a part of a drive unit of the stern drive of FIG. 1 .
FIG. 7 is a lateral view, opposite to that of FIG. 4 .
FIG. 8 is a cross-sectional view, taken along the line VIII-VIII of FIG. 1 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of a cooling system for a stern drive according to the present invention is described below with reference to drawings.
Throughout the figures, like components will be identified by like reference numerals.
FIG. 1 shows a stern drive 1 . The stern drive 1 includes a drive unit 5 which is attached to a transom section 2 and has been arranged outboard of a boat 3 , and engine 6 installed inboard of the boat 3 .
Referring to FIG. 1 and FIG. 2 , a drive unit 5 includes a housing 7 ; a horizontal shaft 8 connecting to a driveshaft of an engine 6 ; forward/backward clutches 9 and 10 provided around the horizontal shaft 8 ; bevel gears 11 and 12 provided in the clutches 9 and 10 , respectively; a bevel gear 13 engaged with the bevel gears 11 and 12 ; a vertical shaft 14 connected with a bevel gear 13 by means of spline engagement via a cylindrical joint 13 a ; a bevel gear 15 fixed to a lower end of the vertical shaft 14 ; a propeller shaft 18 where a bevel gear 16 engaged with the bevel gear 15 is fixed; and a propeller shaft 19 where a bevel gear 17 engaged with the bevel gear 15 is fixed. The propeller shaft 19 is fitted receivably around the propeller shaft 18 , being rotatable relatively to the propeller shaft 18 . A propeller 18 a is fixed to the propeller shaft 18 , and a propeller 19 a is fixed to propeller shaft 19 .
Referring to FIG. 1 , FIG. 2 and FIG. 4 , the housing 7 is provided with an upper gear housing 7 a and a lower gear housing 7 b . The upper gear housing contains clutches 9 , 10 , and upper gears having bevel gears 11 , 12 , and 13 . The lower gear housing contains lower gears having bevel gears 15 , 16 and 17 .
In FIG. 2 , the clutches 9 and 10 are hydraulic multiplate clutches, but they may be realized by other clutches like a cone clutch, an electromagnetic clutch, or a dog clutch. A gear pump 20 is attached to a back end of the horizontal shaft 8 . The gear pump 20 pumps up oil (not shown) from the housing 7 , and supplies the oil to the upper gear and the clutches 9 and 10 as lubricant oil, and also supplies the oil to the clutches 9 and 10 as hydraulic oil. The gear pump 20 is mounted to an oil block 21 , which includes control valves or the like (not shown) for controlling the hydraulic oil of the clutches 9 and 10 . The oil block 21 is sealed with a waterproof cover 22 to protect the control valves and other metal components from seawater. The waterproof cover 22 is attached to a back wall of the upper housing 7 a in a portion close to the upper gear.
Though it is not shown in the figure, the oil level in the housing 7 is generally in the vicinity of the position of the top T of the clutches 9 and 10 . When the oil in the housing 7 is reduced, and the oil level decreases, oil is supplied to the housing 7 .
As shown in FIG. 3 and FIG. 4 , the drive unit 5 is provided with a removably attachable cover 25 for the housing 7 . The cover 25 is constituted of side sections 25 s and 25 s and a rear section 25 r . The top of the cover 25 is open. In attaching the cover 25 to the housing 7 , the side sections 25 s and 25 s are horizontally spread against the retention elasticity of the cover 25 and the cover 25 slides to the rear side of the housing 7 until they are properly combined. The cover 25 is fixed by a bolt to a threaded hole 7 da of the boss 7 d , which is formed as a part of the side wall 7 s of the housing 7 , protruding from the side wall 7 s.
The cover 25 does not extend over the top panel 7 c constituting the top face of the housing 7 . With this configuration, the width between the two sides of the cover 25 is smaller than that of a cover overlaying on the top of the housing 7 (e.g., the cover disclosed in the U.S. Pat. No. 6,808,432). Therefore, the cover 25 can be formed into a slim shape according to the width of the housing. Further, since the cover 25 does not include a top, the tilt-up angle of the drive unit 5 can be increased.
As shown in FIGS. 3 and 4 , by removing the cover 25 , the oil level in the housing 7 can be visually confirmed through the oil level observation window 26 formed on the side wall 7 s of the housing 7 . In fabricating the drive unit 5 , or during oil changes, oil is supplied through the oil draining/supplying opening 7 f by means of a pump after the removal of its cap, which is provided in the front bottom of the housing 7 shown in FIG. 1 . When the oil level in the housing 7 decreases, oil is supplied from a reservoir tank (not shown) into the housing 7 via a pipe. The reservoir tank is provided in the ship.
As shown in FIGS. 3 , 4 and 5 , the drive unit 5 is provided with two conduits 30 each of which has a water outlet 30 a . The water outlets 30 are directed respectively to the left and to the right of the side wall 7 s of the housing 7 , to a location near the bevel gears 11 , 12 and 13 , and the clutches 9 and 10 . The water outlet 30 a can be provided at a height in the vicinity of the top T of the clutches 9 and 10 in the housing 7 .
The bevel gears 11 , 12 and 13 , and the clutches 9 and 10 generate frictional heat. This frictional heat is transferred to the housing 7 through oil, which serves as a heat medium. According to this, the cooling system will serve efficiently by discharging cold water from the water outlet 30 a to a specific portion of the side wall 7 s , i.e., the portion near the bevel gears 11 , 12 and 13 , and the clutches 9 and 10 .
As with the illustrated embodiment, a cooling system with such positioning of a water outlet is particularly effective for a drive unit incapable of direct discharge of water to the back wall of the upper housing 7 a because of the existence of the above-mentioned waterproof cover or the like, or for a drive unit having a gap between the oil level in the housing 7 and the top panel 7 c , which is the top of the housing 7 .
In the illustrated embodiment, the water outlet 30 a is directed to the front of the side wall 7 s from the rear. Further, in the illustrated embodiment, the water outlet 30 a is directed substantially horizontally, in a direction along the side wall 7 s of the housing 7 .
As described above, the cover 25 has a slim shape according to the width of the housing 7 . Therefore, the conduit 30 has an outer diameter no more than the protruding height of the boss 7 d . Such a structure improves workability since the cover 25 can be attached or removed to or from the housing 7 without interference from the conduit 30 . Further, as shown in FIG. 8 , the conduit 30 is arranged so that the inner circumference plane of the water outlet 30 a comes substantially into contact with a virtual plane extended backward from the side wall 7 s of the housing 7 .
Though this is not shown in the figure, another embodiment may be arranged so that the water outlet is opposed to the side wall 7 s . A single side wall 7 s may have a plurality of water outlets. Though the water outlet 30 a shown in the figure has a circular shape, the water outlet 30 a may have a rectangular shape, with its long side laid along the side wall 7 s of the housing 7 .
As shown in FIG. 6 , one end of each conduit 30 is connected to a hose joint 31 that protrudes upward from the rear section of the housing 7 . The hose joint 31 is communicated with the hollow section 32 in the housing 7 . With reference to FIG. 6 and FIG. 1 , the hollow section 32 is opened to the water-introducing inlet 33 provided on the bottom face of an antiventilation plate 7 g.
When the boat 3 moves forward, as indicated by an arrow in FIG. 6 , the water under the antiventilation plate 7 g enters into a hollow section 32 via the water-introducing inlet 33 due to the dynamic pressure of water flow in the centrifugal direction, which is generated by the propellers 18 a and 19 a . The water is then pushed upward through the conduits 30 and 30 , and is then discharged strongly from the water outlet 30 a.
A conduit 30 is contained between the cover 25 and the housing 7 , and the cover 25 defines a space X to which water is discharged from the water outlet 30 a , and a drain section for draining the discharged water. In the illustrated example, the drain section is formed by the gaps between edges 25 b and 25 c of the cover 25 and the housing 7 . Note that the drain section may be formed by a through hole (not shown) formed on a lower portion of the cover 25 . The through hole and the gaps may be provided as the same member. In other possible structures, the gaps are closed, and water is drained via only the through hole. However, it should be noted that the cover 25 can be manufactured more easily in the case of the illustrated example in which only the gaps are formed between the cover 25 and the housing 25 , compared with a structure having a through hole on the cover 25 .
Referring to FIG. 3 and FIG. 4 , the housing 7 has a flange section 7 h on the front end of the side wall 7 s . The flange section 7 h protrudes in the lateral direction. A bell housing 36 is connected to the housing 7 with the bolt 37 via the flange section 7 h . The gap for draining water is provided between the outer periphery of the flange section 7 h and the inner periphery of the front edge 25 b of the cover 25 . Since the flange section 7 h protrudes from the side wall 7 s of the housing 7 , the water discharged from the outlet 30 a , except for the water drained through the gap between the flange section 7 h and the front edge 25 b of the cover 25 , collides with the flange section 7 h , and is brought back to the space X between the side wall 7 s and the cover 25 . As a result, the heat removing effect is improved. The top panel 7 c of the housing 7 protrudes outward from the side wall 7 s of the housing 7 .
The conduit 30 may be formed by an elastic tube. Referring to FIG. 4 , the water outlet 30 a of the conduit 30 is fixed to the flange section 22 a of the waterproof cover 22 . The flange section 22 a has a bolt hole (not shown) into which the bolt 38 is inserted to fix the waterproof cover 22 to the housing 7 . A boss 7 j into which the bolt 38 is screwed protrudes from the side wall 7 s of the housing 7 . The boss 7 j extends horizontally along the side wall 7 s of the housing 7 .
With reference to FIGS. 3 , 4 and 7 , ribs 7 r 1 and 7 r 2 are formed on the side wall 7 s of the housing 7 . The ribs 7 r 1 and 7 r 2 extend horizontally along the side wall 7 s . In the illustrated example, the rib 7 r 1 is formed substantially at the same level as that of the central axis of the horizontal shaft 8 . In the illustrated example, the rib 7 r 2 is formed substantially at the same level as that of the engagement position of the bevel gears 11 , 12 and the bevel gear 13 . In the illustrated example, the rib 7 r 2 is provided on only one of the side walls 7 s (side wall shown in FIG. 4 ). The oil level observation window 26 includes a peripheral wall 7 k that protrudes from the side wall 7 s of the housing 7 . The upper rib 7 r 1 is connected to the peripheral wall 7 k of the oil level observation window 26 and the boss 7 d . The lower rib 7 r 2 is connected to the bosses 7 j and 7 d . The peripheral wall 7 k is distant from the boss 7 j on the oil level observation window 26 , but they may be connected by a rib not shown in the figure. The ribs 7 r 1 and 7 r 2 are also connected to the flange section 7 h on the front of the side wall 7 s of the housing 7 via bosses 7 d and 7 d , respectively. As shown in FIG. 8 , gaps for directing water through are formed between the ribs 7 r 1 / 7 r 2 and the inner wall of the cover 25 , and between the peripheral wall 7 k of the oil level observation window 26 and the inner wall of the cover. Though it is not shown in the figure, the gap for directing water through is also formed between the boss 7 j and the inner wall of the cover 25 . Each side wall 7 s of the housing 7 may have three or more ribs aligned in the horizontal direction.
The following protruding portions formed on the side wall 7 s of the housing 7 serve to increase the strength of the housing 7 : the ribs 7 r 1 and 7 r 2 , the peripheral wall 7 k , and the bosses 7 d and 7 j of the oil level observation window 26 . Further, being provided lower than the water outlet 30 a , they also serve to increase the surface area of the side wall 7 s of the housing 7 . This increases the heat removing effect through the water discharge. Furthermore, depending on the flow rate of the water discharged from the water outlet 30 a , the heat removing effect due to the water discharge from the housing 7 may further be increased by limiting the natural fall of water discharged from the water outlet 30 a , or by decreasing the falling speed of the water to increase the contact time of water and the housing 7 . This improves the heat absorption effect of the water discharged to the space X formed between the side wall 7 s of the housing 7 and the cover 25 . Consequently, the protruding portions serve to ensure a high heat removing effect even when the propulsion speed of the ship is low and the amount of water discharged from the water outlet 30 a is small.
The drawings show one embodiment of the present invention, but it should be understood that the scope of the present invention includes some modifications of the embodiment. | The subject invention provides a cooling system for a stern drive, including: a conduit having a water outlet for discharging ambient water, which is introduced by using a water current generated by propulsion of a boat to which said stern drive is mounted, the water outlet being directed toward a side wall of a housing containing a gear and a clutch where heat is generated, at a location near the gear and the clutch; and a cover removably attachable to the housing, the conduit being contained between the cover and the housing, the cover defining a space to which water is discharged from the water outlet and a drain section for draining the water. | 1 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Present Invention
[0002] The present invention relates to spotlights, and more particularly to a moisture-proof spotlight that is invulnerable to moisture.
[0003] 2. Description of Related Art
[0004] Referring to FIG. 1 , a conventional spotlight 90 is a lamp capable of changing its lighting direction vertically and horizontally. The spotlight 90 comprises a lamp housing 91 and a support 92 pivotally supporting the lamp housing 91 from below.
[0005] In the lamp housing 91 , a partition 94 divides the interior of the lamp housing 91 into a lamp compartment 91 a and a driving-device compartment 91 b.
[0006] A lamp assembly 95 is pivotally installed in the lamp compartment 91 a. A vertical driving device 96 is installed in the driving-device compartment 91 b and affixed to the middle partition 94 . A horizontal driving device 97 is fixedly installed inside the support 92 .
[0007] A curved rack 95 a is provided behind the lamp assembly 95 , for the vertical driving device 96 to engage and move the lamp assembly 95 . In response to the driving force from the vertical driving device 96 , the lamp assembly 95 tilts up and down in the lamp compartment 91 a of the lamp housing 91 , so as to provide a vertically changeable lighting angle.
[0008] A ring gear 91 c is provided below the lamp housing 91 , for the horizontal driving device 97 to engage and move the lamp assembly 95 . In response to the driving force from the horizontal driving device 97 , the lamp housing 91 , together with the lamp assembly 95 installed in its lamp compartment 91 a, swivels right and left against the support 92 , so as to provide a horizontally changeable lighting angle.
[0009] However, the conventional spotlight 90 is structurally defective because the horizontal driving device 97 is fixed inside the support 92 . In damp weather conditions, once rainwater permeate into the support 92 of the spotlight 90 , the horizontal driving device 97 tends to get damaged by moisture.
SUMMARY OF THE INVENTION
[0010] In view of this, the primary objective of the present invention is to provide a moisture-proof spotlight, which improves the prior-art device by making its vertical and horizontal driving devices both installed in its lamp housing instead of the support, so that the driving devices are secured from moisture and in turn the whole spotlight is durable even in damp weather conditions.
[0011] The moisture-proof spotlight comprises a lamp housing, a support pivotally supporting the lamp housing from below, and a lamp assembly pivotally installed inside the lamp housing. The lamp housing contains therein a moisture-proof partition set, a vertical driving device, a horizontal driving device and a stationary gear.
[0012] The moisture-proof partition set includes a vertical partition and a horizontal partition. The vertical partition divides the interior of the lamp housing into a lamp compartment and a driving-device compartment, and the lamp assembly is pivotally installed in the lamp compartment of the lamp housing. The horizontal partition forms a floor of the driving-device compartment of the lamp housing.
[0013] The stationary gear is located below the horizontal partition of the moisture-proof partition set, and combined with the support as an integrated structure through a fixing member.
[0014] The vertical driving device is fixed to the vertical partition of the moisture-proof partition set, and drives the lamp assembly to tilt up and down in the lamp compartment of the lamp housing, so as to change the illuminating angle of the moisture-proof spotlight vertically.
[0015] The horizontal driving device is fixed to the horizontal partition, and drives the lamp housing and the lamp assembly to swivel right and left against the support, so as to change the illuminating angle of the moisture-proof spotlight horizontally.
[0016] The lamp housing of the moisture-proof spotlight is preferably composed of an upper half and a lower half.
[0017] As a preferred embodiment, the upper half of the lamp housing has a first slot and the lower half of the lamp housing has a second slot, in which the vertical partition has laterals thereof inlaid to and retrained by the first slot and the second slot, so that the driving-device compartment in the lamp housing is less affected by moisture in damp weather conditions.
[0018] In the disclosed moisture-proof spotlight, the vertical driving device and the horizontal driving device are both installed in the driving-device compartment of the lamp housing, and are secured from moisture, so the whole spotlight is advantageously durable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a cross-sectional view of a conventional spotlight.
[0020] FIG. 2 provides a perspective view and a cutaway view of a moisture-proof spotlight according to the present invention.
[0021] FIG. 3 shows the moisture-proof spotlight of FIG. 2 with its upper half lifted.
[0022] FIG. 4 depicts components of the moisture-proof spotlight that are installed in its lamp housing.
[0023] FIG. 5 is a partially exploded view of the moisture-proof spotlight with the upper half removed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0024] Referring to FIG. 2 , the disclosed moisture-proof spotlight 10 is a versatile spotlight with its illumination changeable vertically and horizontally. The moisture-proof spotlight 10 comprises a lamp housing 20 , a support 30 pivotally supporting the lamp housing 20 from below, and a lamp assembly 40 pivotally installed inside the lamp housing 20 .
[0025] As shown in FIG. 2 through FIG. 5 , the lamp housing 20 is composed of an upper half 21 and a lower half 22 , and contains therein a lamp assembly 40 , a moisture-proof partition set 50 , a vertical driving device 60 , a horizontal driving device 70 and a stationary gear 80 .
[0026] The upper half 21 of the lamp housing 20 is provided with a first slot 23 , and the lower half 22 of the lamp housing 20 is provided with a second slot 24 which is positional corresponding to the first slot 23 of the upper half 21 . The lower half 22 of the lamp housing 20 is further provided with a through hole 28 and a plurality of fixing ribs 29 .
[0027] The moisture-proof partition set 50 comprises a vertical partition 51 and a horizontal partition 52 . When assembled, the vertical partition 51 has its four edges inlaid into and retained by the first slot 23 and the second slot 24 formed in the lamp housing 20 , so that the interior of the lamp housing 20 is divided into a lamp compartment 25 a and a driving-device compartment 25 b. Particularly, the lamp assembly 40 is pivotally installed in the lamp compartment 25 a of the lamp housing 20 .
[0028] The horizontal partition 52 of the moisture-proof partition set 50 has a plurality of locking holes 53 that are positional corresponding to the fixing ribs 29 at the lower half 22 of the lamp housing 20 . When assembled, the horizontal partition 52 is fixed to the lower half 22 of the lamp housing 20 by fixing members, while a sufficient space is left below the horizontal partition 52 for receiving the stationary gear 80 . This configuration, as defined herein, refers to that the horizontal partition 52 , when assembled, forms a floor of the driving-device compartment 25 b of the lamp housing 20 .
[0029] The driving-device compartment 25 b of the lamp housing 20 is sealed by the vertical partition 51 and the horizontal partition 52 of the moisture-proof partition set 50 and obtains excellent moisture-proof effect.
[0030] The vertical driving device 60 comprises a reversible motor 61 and a pinion 62 . The vertical driving device 60 is fixed to the vertical partition 51 of the moisture-proof partition set 50 , and is received in the driving-device compartment 25 b of the lamp housing 20 .
[0031] The horizontal driving device 70 comprises a reversible motor 71 and a pinion 72 . The horizontal driving device 70 is fixed to the horizontal partition 52 of the moisture-proof partition set 50 , and is received in the driving-device compartment 25 b of the lamp housing 20 .
[0032] The lamp assembly 40 has each of its two laterals provided with a pivot 41 , while a recessed rack 42 extends along a back of the lamp assembly 40 .
[0033] For pivotally installing the lamp assembly 40 into the lamp compartment 25 a of the lamp housing 20 , the upper half 21 of the lamp housing 20 has upper pivot seats 26 for pivotally supporting the pivots 41 of the lamp assembly 40 jointly with lower pivot seats 27 provided correspondingly at the lower half 22 of the lamp housing 20 . When the upper half 21 and the lower half 22 of the lamp housing 20 are combined, the upper pivot seats 26 of the upper half 21 and the lower pivot seats 27 of the lower half 22 jointly form two pivot seats that allow the pivots 41 of the lamp assembly 40 to be pivotally installed therein.
[0034] When the lamp assembly 40 is pivotally installed in the lamp compartment 25 a of the lamp housing 20 , the vertical driving device 60 is fixed to the vertical partition 51 of the moisture-proof partition set 50 , and has its pinion 62 engaged with the recessed rack 42 of the lamp assembly 40 . In response to the driving force coming from the vertical driving device 60 through the pinion 62 , the lamp assembly 40 tilts up and down in the lamp compartment 25 a of the lamp housing 20 , so as to change its illuminating angle vertically.
[0035] The stationary gear 80 has a plurality of locking holes 81 . The support 30 has a raised ring 31 that is provided with a plurality of fixing ribs 32 at its inner periphery. The fixing ribs 32 are positional corresponding to the locking holes 81 of the stationary gear 80 , so that fixing member can pass through the locking holes 81 and fix the stationary gear 80 to the raised ring 31 , making the stationary gear 80 combine with the support 30 as an integrated structure.
[0036] Referring to FIG. 2 through FIG. 5 , during assembly, the raised ring 31 of the support 30 has its top pass through the through hole 28 of the lower half 22 of the lamp housing 20 and partially exposed outside the lower half 22 for the stationary gear 80 to affix.
[0037] When the horizontal partition 52 of the moisture-proof partition set 50 forms the floor of the driving-device compartment 25 b of the lamp housing 20 , the stationary gear 80 is located below the horizontal partition 52 of the moisture-proof partition set 50 . The horizontal driving device 70 is fixed to the horizontal partition 52 of the moisture-proof partition set 50 , and has its pinion 72 engaged with the stationary gear 80 . In response to the driving force coming from the horizontal driving device 70 through the pinion 72 , the lamp housing 20 , together with the lamp assembly 40 installed in its lamp compartment 25 a, swivels right and left against the support 30 , so as to change its illuminating angle horizontally.
[0038] To sum up, the disclosed moisture-proof spotlight 10 features that the vertical driving device 60 and the horizontal driving device 70 are both installed inside the driving-device compartment 25 b of the lamp housing 20 , so that the driving devices are secured from moisture and in turn the whole spotlight is durable even in damp weather conditions. | A moisture-proof spotlight includes a lamp housing, a support pivotally supporting the lamp housing from below and a lamp assembly pivotally installed inside the lamp housing, wherein the lamp housing contains therein a moisture-proof partition set provided for a vertical driving device and a horizontal driving device to affix thereto and also together installed inside the lamp housing for moisture-proof, thereby the defect of a conventional spotlight due to its horizontal driving device installed in the support tended to be affected by moisture is capably eliminated. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improved signal processing circuit for a movement detecting encoder device which tracks the movement of a body by means of sensors which track the movement of a scale attached to the body.
Such movement detecting encoders are well known in the art, as for example the magnetic rotary encoder disclosed in U.S. Pat. No. 4,774,464. A similar example of a magnetic rotary encoder is shown in FIG. 5a. A magnetic drum 50 is provided with a scale, which is an array of magnetic elements 51, that produces a changing magnetic field as magnetic drum 51 rotates. The changing magnetic field is detected by MR sensors 1a, 1b. Signal processing circuits for such encoders are also well known in the art, for example, as disclosed in U.S. Pat. No. 4,359,685. FIGS. 5 shows MR sensors 1a, 1b in detail in the context of a similar typical signal processing circuit made up of phase A and phase B. MR sensor 1a comprises magnetoresistive elements Ra1-Ra4 configured in a bridge circuit, and is provided with source voltage V cc . Further, MR sensor 1a is connected to phase A of the signal processing circuit by means of sensor output nodes P1 and P2 Sensor output P1 is connected to the inverting terminal of comparator 2 a by means of resistor R1a, and sensor output P2 is connected to the non-inverting terminal by means of resistor R2a.
The construction of MR sensor 1b and its connection to phase B of the signal processing circuit mirrors that of MR sensor 1a. Typically, the output of the phase B output has a phase difference of 90° (π/2) with the phase A output, and both signals are typically further processed in signal processing means such as a detection signed generator 3.
As shown in FIG. 6b, e1 and e2 represent typical sensor output waveforms at nodes P1 and P2, respectively. These waveforms are 180° out of phase with each other and intersect at action reference voltage V cc /2 Comparator 2a is provided with source voltage V cc =V cc in this example, so that the output of the comparator 2a alternates between V cc and 0 v (ground) and similarly has action reference voltage V cc /2. The output A of the comparator is fed back to the noninverting terminal of comparator 2a through a feedback resistor R3a causing a voltage displacement in the input waveform to the non-inverting terminal of comparator 2a, from e2 to e3. The voltage amplitude R2a, R3a, the sensor output action reference voltage V 2 and the comparator 2a output voltage V A according to the following equation:
(1) Amplitude displacement=(V A -V 2 )×[R2a/(R2a+R3a)] When the comparator output is high, V A is approximately equal to V cc . As mentioned earlier, the action reference voltage V 2 of sensor output waveform e2 is V cc /2, so when the comparator output is high the amplitude displacement is: ##EQU1## When the comparator output is low, V A is approximately 0, and the amplitude displacement is: ##EQU2## Thus, the magnitude of the amplitude displacement when the source voltage of the comparator is equal to the source voltage of the sensors is the same whether the comparator output is high or low; only the sign of the amplitude displacement changes.
However, when the source voltage V cc2 of the comparator is different from the source voltage V cc of sensor 1a, the magnitude of the amplitude displacement changes as well. This problem arises in prior art due to the positive feedback to the non-inverting terminal of comparator 2a through resistor R3a, which is provided to lessen the effect of noise that is typically present in a sensor output waveform as shown in FIG. 8.
For example, suppose V cc2 equals V cc /3 as in FIG. 7. Waveform e3, the input to the non-inverting terminal of comparator 2a, is formed as before, according to equation (1). However, since V cc2 is not equal to V cc , the magnitude of factor V A -V cc will change when V A toggles between its high and low values. When the output of the comparator is high, amplitude displacement is given by:
V.sub.fh2 =(V.sub.cc /3-V.sub.cc /2)×[R2a/(R2a+R3a)]
When the comparator output is low amplitude displacement is given by:
V.sub.fL2 =(0-V.sub.cc /2)×[R2a/(R2a+R3a)]
Since V fH2 =(V cc /3-V cc /2)≠(0-V cc /2)=V fL2 the amplitude displacement changes as the output of the comparator changes.
Differing amplitude displacement is a problem because it causes a distortion of the duty cycle of comparator 2a output. The duty cycle is not distorted when the source voltage V cc2 of comparator is equal to the source voltage of MR sensor 1a because the amplitude displacement is the same.
An undistorted duty cycle means that the time interval while the comparator is in the high output level or low output level accurately represents the time interval between appropriate intersection points of the sensor output waveforms. For example, referring to FIG. 6, two "output waveform intersection points" i.e. the intersection points of the sensor output waveforms e1 and e2, are labelled x1 and x2. Between x1 and x2, along the x-axis, output waveform e1, the input to the inverting terminal of comparator 2a, is greater than the output waveform e2, the input to the non-inverting terminal of comparator 2a. Therefore the comparator output V A should be low for this time interval. However, because of positive feedback, waveform e3 rather than e2 is the input to the non-inverting terminal of comparator 2a, so that the comparator output follows the intersection points of waveforms e3 and e1 ("triggering intersection points"), Y1 and Y2, rather than corresponding output intersection points x1 and x2 of waveforms e2 and e1.
Because the amplitude displacement of waveform e3 is equal in magnitude but opposite in sign when the comparator output toggles, the triggering intersection points y1 and y2 are both offset from corresponding output intersection points x1 and x2, respectively, by the same magnitude and in the same direction. Consequently the time interval during which the comparator output is low accurately represents the time interval between the output intersection points x1 and x2, and the duty cycle is not distorted.
However in FIG. 7 where V cc2 is less than V cc there is a distortion in the duty cycle. The triggering intersection points y3 and y4 are offset from the corresponding output intersection points x1 and x2, respectively, in different directions because of differing amplitude displacement (V fL2 ≠V fh2 ). Thus the time interval between y3 and y4 is greater than the time interval between corresponding output intersection points x1 and x2, respectively. Consequently the time interval of the low comparator output does not accurately represent the time interval between output intersection points x1 and x2, and there is a distortion of the duty cycle.
In summary, a difference between the source voltage V cc2 of the comparator 2a and the source voltage V cc of sensor 1a results in a distortion of the duty cycle, or in other words, an inaccurate representation of the sensor output waveforms.
SUMMARY OF THE INVENTION
The present invention provides an improved signal processing circuit for an encoder such that a difference between sensor source voltage and comparator source voltage will not cause a distortion in the duty cycle. An additional positive feedback loop is provided to the inverting terminal of the comparator such that there is an amplitude displacement of both sensor output waveforms as they are input to the comparator. The additional amplitude displacement on the second sensor output waveform offsets the differing amplitude displacements of the first sensor output in such a way that when the sensor source voltage is different than the comparator source voltage the time intervals between the triggering intersection points accurately represents the time intervals between output waveform intersection points.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a signal processing circuit as provided by the present invention.
FIG. 2 is a wave diagram showing sensor output waveforms, comparator input waveforms and comparator output waveforms according to the present invention.
FIG. 3 is a wave diagram showing sensor output waveforms, comparator input waveforms and comparator output waveforms when V cc2 is less than V cc according to the present invention.
FIG. 4 is a schematic diagram of an embodiment of the present invention.
FIG. 5a is a perspective view of a prior art magnetic rotary encoder.
FIG. 5b is a schematic diagram of the magnetic sensors in the magnetic rotary encoder.
FIG. 5c is a schematic diagram of a prior art signal processing circuit for a magnetic rotary encoder.
FIG. 6 is a wave diagram of a prior art signal processing circuit showing sensor output waveforms, comparator input waveforms and comparator output waveforms.
FIG. 7 is a wave diagram of a prior art signal processing circuit showing sensor output waveforms, comparator input waveforms and comparator output waveforms V cc2 is less than V cc .
FIG. 8 is a wave diagram showing a typical output waveform of a magnetic resistance sensor.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the signal processing circuit provided by the present invention is shown in FIG. 1. Stage A and stage B of the circuit are identical and thus the discussion will focus on stage A. MR sensor 1a contains an associated bridge circuit 10a and is provided with source voltage V cc . P1 and P2 are the balancing points and A1 and A2 are the output terminals of bridge circuit 10a. R1a and R2a are resistors provided between the output terminals A1 and A2, respectively, of sensor 1a and the inverting and non-inverting input terminals, respectively, of comparator 2a. Comparator 2a is provided with source voltage V cc2 which is applied through resistor R9. Feedback buffer 4 comprises inverters 41 and 42. The output of comparator 2a passes through both inverters 42 and 41 before being fed through resistor R5 to the non-inverting input terminal of 2a while the same output of comparator 2a is passed through only inverter 42 before being passed through resistor R6 and then being fed back to the inverting input terminal of comparator 2a.
FIGS. 2 and 3 are analogous to FIGS. 6 and 7, except that FIGS. 2 and 3 include an additional waveform e4 which is the input waveform to the inverting terminal of the comparator 2a after the output A1 of the sensor is displaced by feedback provided through resistor R6. The voltage displacement of waveform e4 is similar to that of e3 in the prior art, and is given by:
(V.sub.A -V.sub.cc /2) [R1a/(R1a+R6a)]
As in FIGS. 6 and 7 waveform e3 represents the input to the non-inverting terminal of the comparator after the output e2 of the MR sensor 1a is displaced by means of positive feedback provided through R5. The voltage displacement of e3 is given by:
(V.sub.A -V.sub.cc /2) [R2a/(R2a+R5a)]
In the embodiment shown in FIG. 2, the source voltage of the comparator V cc2 is equal to the source voltage of the sensors V cc1 . This results in the same amplitude displacement of both sensor output waveforms whether the comparator output is high or low. The triggering intersection points y5 and y6 are offset in the same amount and in the same direction from the corresponding output intersection points x1 and x2, respectively; consequently, the time interval between the triggering intersection points y5 and y6, and correspondingly the interval during which the comparator output is in the low state, accurately represents the time interval between output intersection points x1 and x2. Thus, there is no distortion of the duty cycle.
FIG. 3 shows waveforms associated with the circuit in FIG. 1 when the source voltage V cc2 of comparator 2a is less than one-half of the source voltage V cc1 of the sensor 2a. Under this condition, the prior art circuitry caused a distortion in the duty cycle. However, in the present invention because of the additional positive feedback provided by R6 to the inverting terminal of comparator 2a, the duty cycle is not distorted. As shown in FIG. 3b, two output intersection points are x1 and x2, and corresponding triggering intersection points of waveforms e3 and e4 are the points Y7 and Y8. Z1 and Z2 are the prior art triggering intersection points of waveforms e3 and e1 that would control the comparator output in prior art signal processing circuits. Because source voltage V cc1 of comparator 2a is less than source voltage V cc2 of sensor 1a, the prior art triggering intersection points Z1 and Z2 are offset in different directions from the output intersection points which would result in a distortion of the duty cycle as explained above. However, the actual triggering intersection points y7 and y8 are offset from corresponding output intersection points x1 and x2, respectively, in the same amount and in the same direction, because of the additional feedback provided through resistor R6 to the inverting input terminal of comparator 2a. The additional feedback displaces the inverting comparator input waveform from e1 to e4 which shifts the actual triggering intersection points which control comparator 2a output. By appropriately selecting the values of the feedback resistors, the time interval of the low output of the comparator 2a between points c7 and c8 will accurately represent the time interval between output intersection points x1 and x2 of the sensor output waveforms e1 and e2.
It is desirable to provide a comparator source voltage lower than the sensor source voltage in order to reduce power consumption in the signal processing circuit, and further in order to miniaturize the circuit.
In addition, to cut down a output current in the MR sensor because it is restricted to minimize the resistance in MR sensor, the power voltage at the side of wave processing circuit will be higher than the one at MR sensor when the overall voltage of MR sensor is designed in lower. Even more, in the example described in FIG. 1, a comparator 2a is formed of open collector comparison circuit, the power voltage V cc of wave processing circuit is added to the output terminal as a pull of voltage, and the condition is explained when the pull of voltage is different from the power voltage of MR sensor. But, when the comparator is formed of push pull circuit, the distortion in the output wave, caused by the difference power voltage between comparator and MR sensor, can be eliminated by the invention. | An encoder has a positive feedback means for feeding back a polarity-inverted output signal to a comparator or an MR sensor circuit thereby to stabilize output waveform duty ratio against deviation between the sensor circuit and comparator in source voltage. | 6 |
The present invention relates to a process for production of polymeric structures with activated surfaces. More particularly, it relates to a process, which, simultaneously, is able to produce particles and/or filaments with chemically active surfaces. The process takes place from the deposition of a polymer solution, aided by a high electric field in a conducting liquid surface for production of particles or filaments with activated surface. The invention even claims the activated polymeric structures obtained according to the process of the invention.
BACKGROUND OF THE INVENTION
A great number of methods for producing particles and/or filaments are described in the literature. Among these methods electrospray and electrospinning have an important highlight, because they produce particles and fibers, respectively.
Electrospray and electrospinning are technologies that use high electric fields for producing particles and/or fibers. In this process a jet of polymeric solution is accelerated and stretched through an electric field. Depending on the physical properties of the solution, the stretched jet can break, generating droplets, which produce micro/nanoparticles, or remain as a filament that after drying, produces fibers of micro/nanometric diameter (O. V. Salata, Tools of nanotechnology: Electrospray, Current Nanoscience 1: 25-33, 2005; S. Ramakrishna, et al., An Introduction to Electrospinning and Nanofibers, World Scientific Publishing Co., 2005).
Electrospray and electrospinning techniques make possible variations almost unlimited in the composition of ejected solutions, showing to be applicable in several technological sectors and for different applications, according to the needs of usage of particles or filaments.
Particles and filaments can be used in several industry segments, in the engineering of fabrics, ceramic fibers and filters, in the production of biomaterials used in treatment and diagnosis, in pharmaceutical, food, cosmetic industry etc. The particles and filaments also can be used in monitoring the pollutant dispersion, and in the quality of the environment protection processes.
The fundamental concepts of electrospray were launched by Lord Rayleigh, in 1882, when he was studying the instabilities in charged liquids (L. Rayleigh, On the equilibrium of liquid conducting masses charged with electricity, Phil. Mag. 14: 184, 1882). Applications of the technique were patented by J. F. Cooley e W. J. Morton (J. F. Cooley, Apparatus for Electrically Dispersing Fluids, U.S. Pat. No. 692,631, 1902; W. J. Morton, Method of Dispersing Fluids, U.S. Pat. No. 705,691, 1902). The explanation of the phenomenon was provided later by J. Zeleny (J. Zeleny, The electrical discharge from liquid points, and a hydrostatic method of measuring the electric intensity at their surfaces, Phys. Rev. 3:69-91, 1914) in 1914, but the physical principles of capillary formation in charged liquids only were established in 1964 by Taylor (G. I. Taylor, Disintegration of water drops in an electric field, Proceedings of the Royal Society 280: 383-397, 1964).
Regarding the electrospinning, which follows the same physical principles of electrospray, the first patent that described the technique, was registered in 1934 by Formhals (A. Formhals, Process and apparatus for preparing artificial threads, U.S. Pat. No. 1,975,504, 1934), when he was developing an apparatus for producing filaments from the force of electrostatic repulsion among the surface charges. Despite the apparatus for electrospinning is extremely simple, its operating mechanism, similar to the electrospray, is very complicated.
When a high voltage (usually in the range from 1 to 30 kV) is applied, the polymeric solution drop, in the ejector nozzle, becomes highly electrified with the charge uniformly distributed over the surface. As a result, the polymeric solution drop will suffer two types of Coulomb electrostatic forces, the repulsion among the surface charges and the force exerted by the external electric field. Under the action of these electrostatic interactions, the solution drop is distorted to a conic form, known as Taylor cone. Since the force of the electric field has exceeded a threshold value, the electrostatic forces can overcome the surface tension of the polymer solution, and then force the ejection of the solution jet from the ejector nozzle.
During the pathway that the electrified jet goes through, from the ejector nozzle to the collector, the process of stretching and lengthening of the jet takes place, and depending on the physical characteristics of the polymeric solution, the jet can break into drops or remain as a filament. In this pathway the evaporation of the solvent and the polymer solidification also take place, leading to the formation of particles or filaments (O. V. Salata, Tools of nanotechnology: Electrospray, Current Nanoscience 1: 25-33, 2005; S. Ramakrishna, et al., An Introduction to Electrospinning and Nanofibers, World Scientific Publishing Co., 2005).
Practically, all the polymers are susceptible to deposition by electrospray or electrospinning. The limitation is to find a solvent able to dilute or emulsify it in order to produce a solution or emulsion able to pass through the capillary of the pumping system. There are polymers for which there is some difficulty for deposition as a function of their physical or electrical properties, but adjusts of these parameters by means of the use of additives, variation of concentration etc, allow the use of these polymers.
Several polymers have been used industrially, such as Nylon, Polyester, Polyacrylonitrile, polyvynil alcohol, Polyurethane, Polylactic acid etc. Conventionally, the electrospinning technique uses preponderantly a solution of polymers in organic solvents, such as chloroform, formic acid, tetrahydrofuran (THF), dimethylformamide (DMF), acetone and alcoholic solvents.
The need for chemical activation of polymeric surfaces emerged together with the development of the first polymers. Generally, the simpler the polymeric chain, the smaller the reactivity. This generally implies in technical difficulties related mainly to dissolution and adhesion to other materials. The change of the polymers structure by introduction of new radicals in the chains, allowed generating new families of polymers with their own physicochemical properties.
In certain situations, it is necessary to use a polymer with an inert inside, but with reactive external surface in order to allow adhesion to other materials, or even to perform specific chemical reactions. Based on this need, from the beginning of the nineties, several techniques based on physical or chemical phenomena were developed, searching the superficial activation of polymeric materials. Among the several physical techniques employed, it is highlighted the electrostatic discharges at atmospheric pressure, the low energy ion implantation, and the low temperature plasma discharge in a reduced pressure environment.
The electrostatic discharges at atmospheric pressure consist in ionizing the environment air, or a gas at atmospheric pressure nearby the surface of an inert polymeric material. Such a phenomenon promotes chemical reactions between the reactive species generated by discharge and the polymer surface. Their main advantages are the simplicity and low cost of technique execution; however, their great disadvantage is the susceptibility of the material activated when exposed to the environment, reacting with any compounds present in the atmosphere and returning to make passive the surface or, even contaminating it (R. A. Wolf, Surface activation systems for optimizing adhesion to polymers, ANTEC™ 2004, Conference Proceedings).
The low energy ion implantation technique consists in producing and accelerating ions of interest, against the polymeric surface with controlled energy. This technique is extremely sophisticated and expensive, but allows to select the ions and to control their energies. Furthermore, the technique uses an ion beam extremely collimated, reaching a reduced area to be activated, what makes the processing of great areas, difficult and slow (G. Mesyats et al., Adhesion of polytetrafluorethylene modified by an ion beam, Vacuum 52:285-289, 1999).
The third technique consists in the exposure of polymeric surface to a low temperature plasma discharge, in a reduced pressure environment. The discharge in plasma allows a reasonable control of existing active species as a function of the gases employed to generate plasma. Depending on the plasma characteristics, this technique also can be known as plasma-immersion ion implantation (A. Kondyurin et al., Attachment of horseradish peroxidase to polytetrafluorethylene (teflon) after plasma immersion ion implantation, Acta Biomaterialia 4:1218-1225, 2008). The control of pressure and reaction gases flow allows controlling the concentration of active species and, consequently, the final activation degree of the produced surface. The need for vacuum in the environment before injection of reactive gases raises the costs and makes difficult the process (P. K. Chu et al., Plasma-surface modification of biomaterials, Mater. Sci. Eng. R36:143-206, 2002).
Among the great variety of chemical techniques for superficial activation, it is highlighted those of copolymer synthesis combining polymers chemically inert and active directly. These techniques have several economic advantages as easy manufacturing inclusive for the staggering process. However, from the distinct characteristics of surface energy of the employed polymers, the active sites can migrate to the inside of the inert polymer, reducing or eliminating totally the final product activity. Such phenomenon is highlighted as a disadvantage of the process. An option for eliminating this problem consists in grafting a layer of active polymer on an inert polymer substrate. In some cases, the grafting is aided by plasma. Even solving the problem of migration of the active sites, this process implies in the increase of steps necessary for obtaining the final product, (K. Kato et al., Polymer surface with graft chains, Progress in Polymer Science 28:209-259, 2003).
Other techniques for modifying the polymeric surfaces involve also treatments with solvents, acid or basic solutions and mechanical abrasion V. I. Kestelman, Physical methods of polymer material modification, Khimiya (Moscow), 1980). Most of these techniques present certain disadvantages, as for example, the production of industrial effluents, excessive degradation of the polymer, high production costs, aggregation of undesirable aspects to the polymer properties etc.
SUMMARY OF THE INVENTION
The present invention relates to a process for production of polymeric structures with activated surfaces. The process demonstrated to be simple, fast, with a high production capacity and low operational costs. The process occurs by deposition of a polymers solution, aided by a high electric field, on a conducting liquid surface for production of particles and/or filaments with activated surface.
According to the present invention it is described a process for production of activated polymeric structures, consisting of the following steps:
(i) prepare a polymeric solution or emulsion or suspension or dispersion composed by at least one solute, and at least one solvent, and
(ii) eject the polymeric solution or emulsion or suspension or dispersion through an ejector nozzle, aided by an electric field, on a liquid surface.
Thus, the present invention allows the production of particles and/or filaments with surfaces chemically activated by a sole process.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 : The figure describes a configuration of the ejection process, which allows getting particles and/or filaments with the activated surface. In this figure the polymeric solution ( 1 ) pass through the piping ( 2 ) arriving to the capillary tube ( 3 ), which is connected to one of the poles of the high voltage source ( 4 ) by the electric conductor ( 5 ). The other pole of the high voltage source ( 6 ) is connected to the conducting liquid surface ( 9 ) contained in the container ( 8 ). The polymeric solution jets ( 7 ) ejected from the capillary tube ( 3 ) can form polymeric particles or filaments, depending on the physical properties of the polymeric solution. The particles or filaments suffer the reaction that activates their surface on the conducting liquid surface ( 9 ), where they are collected.
FIG. 2 : Image of scanning electron microscopy of polystyrene particles by employing the method of the present invention.
FIG. 3 : Image of scanning electron microscopy of polystyrene particles by employing the method of the present invention with a greater magnification.
FIG. 4 : Image of scanning electron microscopy of a combination of polymethylmetacrylate filaments and particles, in a bead necklace shape, obtained employing the method of the present invention.
FIG. 5 : Images of fluorescence obtained with the confocal microscope, without using the Sulfo-NHS/EDC treatment. (A) Commercial sample, fluorescence intensity multiplied ten times (10×); (B) sample NaBr_AA77L, fluorescence intensity multiplied five times (5×); (C) sample NaBr_AA80L, fluorescence intensity without using the multiplier (1×).
FIG. 6 : Images of PE (Phycoerythrin) fluorescence obtained with the confocal microscope, without using the Sulfo-NHS/EDC treatment, of sample NaBr_AA37L.
FIG. 7 : Images of GFP (Green Fluorescent Protein) fluorescence obtained with the confocal microscope, without using the Sulfo-NHS/EDC treatment, of sample NaBr_AA38L.
FIG. 8 : Spectra of photo-emission excited by x-ray (XPS) of polystyrene submitted and not submitted to the process of the present invention.
FIG. 9 : Spectra obtained using Fourier Transform Infrared Spectroscopy (FTIR) of polystyrene submitted and not submitted to the process of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a simple, fast process with high production capacity and low cost for production of polymeric structures with activated surfaces. More particularly, it relates to a process that, simultaneously, is able to produce particles and/or filaments with chemically active surfaces.
The mentioned process for production of activated polymeric structures is characterized by the following steps:
(i) prepare a polymeric solution or emulsion or suspension or dispersion comprising at least one solute and at least one solvent, and
(ii) eject the polymeric solution or emulsion or suspension or dispersion through an ejector nozzle, aided by an electric field, on a conducting liquid surface.
The process described in the present invention does not require special conditions, such as vacuum, which make the process expensive and more difficult. It even does not require the use of treatments with chemicals, or mechanical abrasion, which burden the process of activation of the polymeric surfaces because they increase the number of process steps, due to production of industrial effluents, and even can generate an excessive polymer degradation or aggregation of undesirable aspects to the polymer properties.
The process consists in ejecting a polymeric solution or emulsion or suspension or dispersion with the aid of a high electric field on a conducting liquid surface. The ejection process can form particles and/or filaments depending on the physicochemical characteristics of the polymeric solutions employed. Contact of the electrostatically charged particles and/or filaments with the conducting liquid surface allows the activation of the particles and/or filaments surface. Activation results from a physicochemical process which introduces functional groups in the polymeric chain exposed on the particles and/or filaments surface.
The choice of the functional group shall be carried out from the polymer chemical structure and the composition of the conducting liquid surface used, from the knowledge of an expert skilled in the state-of-the-art. Functional groups in the polymeric chain can be organic radicals or inorganic radicals with anionic or cationic nature. Preferably, but not limited to, the radicals can be derived from oxygen (O) and nitrogen (N), such as, hydroxyl (OH − ), carbonyl (C═O), carboxyl (COOH), aldoxyl (COH), amine (NH 2 ), amide (CONH 2 ), ammonium (NH 4 + ). Radicals can be also ions like: bromide (Br − ) or fluoride (F − ) or other functional groups available in the state-of-the-art.
The process of the present invention can be performed from any apparatus allowing eject a polymeric solution or emulsion or suspension or dispersion, aided by a high electric field, on a conducting liquid surface. FIG. 1 shows one of the possible configurations to be employed for obtaining the process of the present invention, among the several existent and susceptible to be used.
In FIG. 1 , it is represented the piping ( 2 ), which leads the polymeric solution or emulsion or suspension or dispersion ( 1 ), the capillary tube ( 3 ), the high voltage source ( 4 ), the conductor ( 5 ) that connects one of the source poles to the capillary tube, o conductor ( 6 ) that connects the opposite source pole to the conducting liquid surface, the particles and/or filaments ejected ( 7 ) during the process, in the collector ( 8 ) containing the conducting liquid surface ( 9 ).
The polymeric solution or emulsion or suspension or dispersion employed in the present invention should comprise at least, one solute and one solvent. The solute should comprise at least, a polymeric material. Overall, it can be used all polymers that can be modified with the purpose to introduce functional groups in the polymeric chain, which are selected from the knowledge of an expert skilled in the state-of-the-art. It can be used polymers such as polystyrene (PS), polymethylmetacrylate (PMMA), nylon, polyester, polyacrylonitrile, polyvinyl alcohol, polyurethane, polylactic acid, and/or any other polymer or copolymer compatible with the solution or emulsification or suspension or dispersion process.
The solute can contain different materials in its composition besides the polymeric material, since they are suitable to the final activity desired. These materials can be additives, surfactants and/or molecules of interest. The materials can present any mechanical, electrical, thermal, magnetic, nuclear and/or optical properties available in the state-of-the-art, important to achieve the final result expected for an expert skilled in the state-of-the-art.
The additives can be considered as substances added with the purpose of optimizing the yield of a property. Surfactants can be considered substances able to change the superficial and interfacial properties of the solution.
The solute can contain molecules of interest according to the final use of the particles or filaments, such as active ingredients or biological molecules like proteins, antigens, antibodies, DNA or RNA fragments, chemicals, active substances; or molecules with magnetic, electrical, thermal, nuclear and/or optical properties available in the state-of-the-art.
Maintenance of the solute in solution or emulsion or suspension or dispersion shall be carried out by any method known in the state-of-the-art, and can be obtained, for example, as a function of the its physicochemical properties or by external mechanical agitation.
The solvent employed can be pure, a mixture or emulsion of organic or inorganic solvents, able to dissolve or emulsify or suspend or disperse the solute. Preferably, it can be used water, alcohol, chloroform (CHL) and tetrahydrofuran (THF), toluene, dimethyl formamide (DMF), or any other solvents available in the state-of-the-art, or a mixture or emulsion thereof, at several proportions, adjusted from the knowledge of an expert skilled in the state-of-the-art.
The mixture or emulsion of solvents, when employed, can contain at least, an inorganic solvent miscible or not, as for example, water. The solvent of suspensions or dispersions should be preferably water or any solvent available in the state-of-the-art able to maintain the solute in suspension or dispersion in a suitable manner, from the knowledge of an expert skilled in the state-of-the-art.
The polymeric solution or emulsion or suspension or dispersion employed should present physicochemical properties suitable to the process, which can be adjusted as a function of the percentages of mixture or emulsion or suspension or dispersion of the solute with the several possible solvents. Physicochemical properties of the polymeric solution or emulsion or suspension or dispersion can be also adjusted as a function of concentration, temperature, pressure. All characteristics can be adjusted from the knowledge of an expert skilled in the state-of-the-art.
The polymeric solution or emulsion or suspension or dispersion employed should also present the surface tension suitable to the process, and can be adjusted as a function of the percentages of mixture or emulsion of the solute with the solvent or adding surfactants compatible with the process, available in the state-of-the-art. Choice of the surfactant depends directly on the composition of the polymeric solution or emulsion or suspension or dispersion employed, and can be adjusted from the knowledge of an expert skilled in the state-of-the-art.
The polymeric solution or emulsion or suspension or dispersion can be transported to be submitted to the process employing any pumping process available in the state-of-the-art.
The polymeric solution or emulsion or suspension or dispersion can present electrical conductivity compatible with the process, a fact that depends directly on its composition. This condition can be adjusted by an expert skilled in the state-of-the-art.
The process of the present invention is aided by a high electric field. The electric field can be continuous, pulsated or alternate or a combination thereof. The high electric field can be produced by any source available in the state-of-the-art, and should be connected directly to the capillary tube(s), or directly to the polymeric solution or emulsion.
Preferably, but not limited to it, it should be used an electric field upper than 100 V/cm until the limit of the dielectric. Voltages to be used shall preferably be above 500 V, and can be positive or negative, since they are able to produce the electric field required to the process described in the present invention. Maximum voltage to be employed should be such that the limit of disruption of the dielectric is not reached, under the conditions of the environment in which the process is carried out, from the knowledge of an expert skilled in the state-of-the-art.
The system employed in the present invention uses at least, an ejector nozzle comprising a capillary tube. The system even provides the possibility of simultaneous use of more than a capillary tube.
The capillary tube can be comprised of any material conducting or not electricity, available in the state-of-the-art. In case of the polymeric solution or emulsion or suspension or dispersion to present electrical conductivity, the capillary tube can be composed by a material not conducting electricity. Preferably, but not limited to, the capillary tube can be made of a metallic material.
The ejection process of the present invention can occur by means of any method existing in the state-of-the-art, from the knowledge of an expert skilled in the state-of-the-art. Preferably, but not limited to, the ejection process can occur by an effect of the high electric field, by an effect of compressed gas, liquid under pressure or a combination thereof. A polymeric solution or emulsion or suspension or dispersion can be ejected at cold temperatures, at room temperature or at hot temperatures, under inert controlled atmosphere, chemically active, or in the environment. These conditions shall be adjusted according to the physicochemical characteristics of the polymeric solution or emulsion or suspension or dispersion from the knowledge of an expert skilled in the state-of-the-art.
The process of the present invention is characterized by the fact that the deposition of the ejected material occurs on a conducting liquid surface contained in a collector.
A conducting liquid surface comprises a solution containing one or more constituents, responsible for the transfer of radicals from the conducting liquid surface to the polymeric structures. The solution of the conducting liquid surface will have physicochemical characteristics enabling deposition and collection of the polymeric structures in such a manner to not allow its dissolution. These physicochemical characteristics will be determined from the knowledge of an expert skilled in the state-of-the-art.
The solution of the conducting liquid surface can be composed by water, organic liquids, inorganic liquids or ionic liquids containing organic or inorganic radicals. Alternately, the solution of the liquid surface can be composed by one or more liquid ionic salts. Preferably, the liquid surface will be composed by an aqueous solution containing organic or inorganic radicals.
The conducting liquid surface also can contain soluble inorganic compounds containing transition metals that act as catalysts in the process of surface activation of the polymeric structures.
A conducting liquid surface can be of neutral, acid or basic nature, and therefore be within the pH range 1 to 14. Preferably, it will have pH upper than 7.
The solution of the conducting liquid surface can contain in its composition, the organic or inorganic radicals of anionic or cationic nature. Preferably, but not limited to, the radicals can be derived from oxygen (O) and nitrogen (N), such as hydroxyl (OH − ), carbonyl (C═O), carboxyl (COOH), aldoxyl (COH), amine (NH 2 ), amide (CONH 2 ), ammonium (NH 4 + ). The radicals can be also ions like: bromide (Br − ) or fluoride (F − ) or other functional groups available in the state of the art. The choice of the radicals shall be carried out from the chemical structure of the polymer and the composition of the conducting liquid surface used, from the knowledge of an expert skilled in the state of the art.
In order to the conducting liquid surface to present electrical conductivity, this should be electrically connected to the opposite pole of the high voltage source aiding the process of the present invention. This assures attraction of the particles or filaments onto the conducting liquid surface. The attraction assures physical contact between the conducting liquid surface and the particles or filaments, allowing its superficial activation.
The conducting liquid surface where it occurs deposition of the particles or filaments can be static or dynamic, and can be horizontal, vertical or forming any angle related to the horizontal plan. Dynamic conducting liquid surfaces should be preferably continuous.
The process of the present invention is characterized by the fact that it produces particles, filaments or combinations of both with radicals of interest on its surface. Particles should present preferable spheroid shapes, with dimensions within the range of some nanometers to some hundreds of micrometers, presenting or not size variability.
Particles produced by the process of the present invention present dimensions within the range of nanometers to micrometers. For its use in diagnostic systems, the particles present preferably dimensions within the range of 50 nm to 500 □m. FIG. 2 presents a image of scanning electron microscopy of polystyrene (PS) particles obtained by employing the process of the present invention for example purposes. The particles generated can be selected dimensionally according to the application from the knowledge of an expert skilled in the state of the art.
The filaments generated can present diameters varying within the range of nanometers to micrometers, and lengths varying from micrometers to centimeters. For use in diagnostic systems, regarding the diameter, the filaments present, preferably, dimensions in the range of 10 nm to 250 □m. FIG. 4 presents a image of scanning electron microscopy of a combination of filaments and particles of polymethylmetacrylate (PMMA), in the shape of a bead necklace, obtained by employing the process of the present invention.
Due to the process characteristics, the particles and/or filaments produced can present a smooth or rough surface, and the superficial roughness presents preferably the shape of cavities or villi with dimensions varying from nanometers to some micrometers. Polystyrene particles (PS) of FIG. 2 present cavities within the range of nanometers that are visible at greater magnifications, as shows FIG. 3 . The roughness increases the surface area and hence, the activated area. Preferably, the particles and/or filaments produced from the process of the present invention, present a rough surface.
Combinations of filaments and particles can present combinations of the individual characteristics, preferably forming structures similar to bead necklaces. The combination of filaments and particles of FIG. 4 , produced with polymethylmetacrylate (PMMA), presents cavities easily visible with a lesser magnification, due to its great dimensions.
The process of the present invention is characterized by the fact that the activation occurs in the contact between electrostatically charged particles and/or filaments and the conducting liquid surface, and the superficial activation occurs by incorporation to the polymeric chain, of functional groups, originating from organic or inorganic radicals of interest, preferably, but not limited to, derivatives of oxygen (O) and nitrogen (N), such as, hydroxyl (OH − ), carbonyl (C═O), carboxyl (COOH), aldoxyl (COH), amine (NH 2 ), amide (CONH 2 ), ammonium (NH 4 + ), or even, ionic radicals, such as bromide (Br − ), fluoride (F − ) or other radicals available in the state-of-the-art.
The present invention is described in detail by the examples presented below. It is necessary to stress that the invention is not limited to these examples, but also includes variations and modifications within the limits, which it can be developed.
Example 1
Production of Polymeric Structures with Activated Surface
The polymeric structures with chemically activated surface were produced from using polymers of polystyrene or polymethylmetacrylate in chloroform or tetrahydrofuran. Solutions of 0.5% to 4.0% w/v of polymer were submitted to the process described in the present invention, by effect of a high electric field at different voltages. Deposition of the polymeric structures produced, was carried out on different conducting liquid surfaces from addition of several substances, resulting in different pH values, at room temperature. Thus, it was obtained particles and/or filaments by means of different conditions described in table 1.
TABLE 1
Characteristics of the samples of polymeric structures
produced and the conditions of the production process.
Conducting
liquid surface
Electric
Substance
Special
Sample
Composition
field
pH
added
conditions
Particles
Polystyrene
6 KV
12.5
NaOH
not
NaOH_AA75L
0.5% w/v in
applicable
chloroform
Particles
Polystyrene
7 KV
1.0
HCl
not
HCl_AA76L
0.5% w/v in
applicable
chloroform
Particles
Polystyrene
7 KV
6.7
NaBr
not
NaBr_AA77L
0.5% w/v in
applicable
chloroform
Particles
Polystyrene
5 KV
6.7
NaBr
not
Mag_NaBr_AA68L
0.5% w/v in
applicable
chloroform +
Fe 2 O 3
Nanoparticles
Particles
Polystyrene
15 KV
6.7
NaBr
Atomization by
Arcomp_NaBr_AA80L
1.0% w/v in
compressed air
chloroform
Filaments
Polymethyl-
9 KV
6.7
NaBr
not
NaBr_AA37L
metacrylate
applicable
1.0% w/v in
chloroform
Particles
Polystyrene
6.5 KV
6.7
NaBr
not
NaBr_AA38L
4.0% w/v in
applicable
tetrahydro-
furan
Example 2
Evaluation of the Binding Capacity of Activated Polymeric Surfaces
Activation of the polymeric surface can be observed through the binding capacity of this surface to other materials, such as molecules of interest. For verification of the binding capacity of the polymeric surface it was used a fluorescent reporter protein as a marker of the active sites. This binding occurs only if there are radicals of the carboxyl (COOH) type on the surface. Thus, the fluorescence detection means that the polymeric surface was efficiently activated by the binding between the surface and the reporter protein.
This test was performed by employing a conventional procedure in the state-of-the-art for determining the activation degree. This consists in using monobasic sodium phosphate (NaH 2 PO 4 ), N-Hydroxysulfosuccinimide (Sulfo-NHS) and 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide (EDC) hydrochloride as reagents to convert carboxyl groups into amino-reactive NHS esters, here named Sulfo-NHS/EDC treatment. Thus, the surface becomes apt to bind to any aminated molecules, which can be proteins, nucleic acids, carbohydrates, fatty acids, chemical compounds, active ingredients, and other polymeric substances available in the state-of-the-art. Aiming to assure the stability of molecules and compounds above mentioned, after coupling with the polymeric surface, the particles or filaments are suspended in a phosphate buffered saline (PBS).
As a reporter protein for comparative tests of the activation and binding capacity of the polymeric surfaces, two types of distinct biological molecules were used. An antibody coupled to the fluorescent molecule Phycoerythrin (PE), with a fluorescence peak located between 560 nm and 630 nm, and GFP (Green Fluorescent Protein), with a fluorescence peak between 514 nm and 530 nm.
The activation degree of all particles was determined from the following protocol. The particles were placed in the wells in a 96-well plate with a filter of 1.2 □m in the bottom, adapted to a vacuum system for filtration; the wells were washed with 900 μl of distilled water and further with 600 μl of NaH 2 PO 4 . Then, it was added 80 μl of NaH 2 PO 4 to each well.
The Sulfo-NHS/EDC treatment was carried out from addition of 10 μl of Sulfo-NHS (50 μg/μl in water) to the wells. Then, it was added 10 μl of EDC (50 μg/μl in water). The plate was incubated at 37° C. under agitation of 200 rpm over 20 minutes. Subsequently, the wells were washed twice with PBS.
It was added to each well, 100 μl of the reporter proteins (200 μg/ml). The plate was again incubated at 37° C., under agitation of 200 rpm, over 2 hours. After a new wash, the particles were re-suspended in 100 μl of PBS and fixed on a microscopy slide by using 2% agarose. Wells without addition of reporter proteins were used as negative control.
Fluorescence detection was carried out from images obtained by confocal microscopy ( FIGS. 5 to 7 ).
Example 3
Comparative Evaluation of the Binding Capacity of the Polymeric Surface Activated from Sulfo-NHS/EDC Treatment
Binding capacity of the surface of the polymeric structures produced by employing the process described in the present invention was compared to the binding capacity or the commercial particles.
Sulfo-NHS/EDC treatment makes feasible the conversion of the carboxyl groups into NHS amino-reactive esters present on activated surfaces, making it more competent to be bound to any aminated molecule.
Table 2 presents indices that allow to analyze comparatively the fluorescence produced by each sample after binding of the fluorescent reporter protein GFP.
TABLE 2
Binding capacity of the samples submitted to Sulfo-
NHS/EDC treatment from fluorescence detection
AS
DI
DI/AS
Sample
Multiplier
(μm 2 )
(UA)
(UA/μm 2 )
HCl_AA76L
10
162.3
1055.7
0.7
NaOH_AA75L
2
182.8
3552.1
9.7
NaBr_AA77L
2
168.0
4662.3
13.9
Mag_NaBr_AA68L
2
126.5
4762.3
18.8
Arcomp_NaBr_AA80L
1
191.7
11420.8
59.6
Commercial
5
43.3
807.1
3.7
AS: area of interest selected, expressed in μm 2 ;
DI: integrated luminosity density: sum of the values of the pixels in the area of interest selected, expressed by arbitrary units (UA);
UA: arbitrary units;
DI/AS: index obtained by dividing the integrated luminosity density by the multiplier and further, by the area of interest, selected.
From the results presented in table 2, it is observed that all samples obtained by the process developed in the present invention, presented results superior to that obtained by the commercial sample, except for the sample HCl_AA76L. Thus, samples obtained by the process developed in the present invention, presented a greater activation degree when compared to the commercial sample activated.
For the sample NaBr_AA77L it was observed a fluorescence about three times more intense than the fluorescence from the commercial product.
For the particles Mag_NaBr_AA68L, magnetic particles due to Fe 2 O 3 nanoparticles in its inside, it was observed a fluorescence about four times more intense than the fluorescence from the commercial product.
For the particles Arcomp_NaBr_AA80L, the process was developed from the use of compressed air. For it, the process was aided by a high electric field of about 15.0 kV. In this process, it was observed fluorescence about fifteen times more intense than the fluorescence from the commercial product.
The sample HCl_AA76L was obtained from HCl addition onto the conducting liquid surface, generating a pH 1.0. Such conditions can be responsible for the low efficiency of the binding capacity of sample HCl_AA76L, characterizing a low activation of the particles.
Example 4
Comparative Evaluation of the Binding Capacity of the Polymeric Surface Activated not Using the Sulfo-NHS/EDC Treatment
Binding capacity of the surface of the polymeric structures produced by employing the process described in the present invention was evaluated not using the Sulfo-NHS/EDC treatment ( FIGS. 6 and 7 ).
Table 3 presents indices that allow analyzing comparatively the fluorescence produced by each sample, without the Sulfo-NHS/EDC treatment, facing the commercial sample.
TABLE 3
Binding capacity of the samples, without Sulfo-NHS/EDC
treatment, from the fluorescence detection
AS
DI
DI/AS
Sample
Multiplier
(μm 2 )
(UA)
(UA/μm 2 )
HCl_AA76L
5
261.3
3203.9
2.5
NaOH_AA75L
5
235.4
3505.7
3.0
NaBr_AA77L
5
195.2
7512.0
7.7
Mag_NaBr_AA68L
3
152.4
3743.4
8.2
Arcomp_NaBr_AA80L
1
67.5
3488.5
51.7
Commercial
5
58.8
512.4
1.7
AS: area of interest selected, expressed in μm 2 ;
DI: integrated luminosity density: sum of the values of the pixels in the area of interest selected, expressed by arbitrary units (UA);
UA: arbitrary units;
DI/AS: index obtained by dividing the integrated luminosity density by the multiplier and, then by the area of interest, selected.
Results obtained without using the Sulfo-NHS/EDC treatment, evidence that all activated particles produced by employing the process of the present invention, present binding capacity greater than the activated commercial particles.
The use of the process described in the present invention allows obtaining highly activated particles, even without using the Sulfo-NHS/EDC treatment, such that they present indices superior to the commercial particles optimized by this treatment.
Thus, samples obtained by the process developed in the present invention, presented a greater activation degree when compared to the activated commercial sample.
In this regard, it can be exemplified with the activation indices for the particles Arcomp_NaBr_AA80L. The activation obtained by the process described in the present invention, employing ejection by compressed air, aided by high voltage, is so efficient that it remains a few sites on the surface requiring Sulfo-NHS/EDC treatment for binding optimization. For this reason, the particles Arcomp_NaBr_AA80L, submitted to Sulfo-NHS/EDC treatment, present a discrete increase of the index DI/AS.
Thus, the process described in the present invention presents the advantage to simplify the process of binding the activated particles to proteins, nucleic acids, carbohydrates, fatty acids, chemical compounds, active ingredients, and other polymeric substances, when putting aside the use of Sulfo-NHS/EDC treatment.
Example 5
Evaluation of the Activated Polymeric Surface
FIG. 5 presents the surface of the polymeric particles produced by employing the process of the present invention. It can be observed the presence of nanopores on the polymeric surfaces, which provide a greater surface area available for activation and binding of proteins, nucleic acids, carbohydrates, fatty acids, chemical compounds, active ingredients, and other polymeric substances.
Increase of the activated surface due to the nanopores, can be evidenced by observation of a fluorescence inside the particle, whereas the particle commercially obtained presents most of its fluorescence on the surface ( FIG. 5 ).
Observation of the images of FIG. 5 allows seeing the different activation degrees obtained by employing the method of the present invention. Comparison of the images 5 A, 5 B and 5 C presenting the commercial particle, NaBr_AA77L and Arcomp_NaBr_AA80L, respectively, allows to conclude that the process described here for particle activation appears to be more efficient and advantageous.
Example 6
Evaluation of the Polymeric Surface Activated by X-Ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR)
Superficial activation can also be observed from X-Ray Photoelectron Spectroscopy (XPS). When employing polystyrene, the technique indicates the disappearance of double carbon bonds (C═C), associated to the benzene ring on the surface, and the simultaneous appearance of the peaks regarding the double Carbon-Oxygen (C═O) and single Carbon-Oxygen bonds (C—O).
FIG. 8 shows the photo-emission spectra of the polystyrene not submitted and therefore, not activated; and the polystyrene activated by the process described in the present invention. In the non-activated polystyrene spectrum it is visible the peak corresponding to single carbon-hydrogen (C—H) and carbon-carbon (C—C) bonds and the peak corresponding to the pi (π) bond of the aromatic ring. In the spectrum of polystyrene activated by the process described in the present invention, it is visible also the peaks corresponding to the single carbon-oxygen bond (C—O) and the double carbon-oxygen bond (C═O). The peak corresponding to the pi (π) bond of the aromatic ring disappeared, indicating the benzenic ring break on the activated polystyrene surface.
The Fourier Transform Infrared Spectroscopy (FTIR) technique allows to verify the activation in polystyrene by the appearance of the band in 1733 cm −1 , which represents the axial deformation of the double Carbon-Oxygen bond (C═O), and in the region 1000-1200 cm −1 , of which bands correspond to the deformation of the single Carbon-Oxygen (C—O) bond, as evidenced in FIG. 9 .
Materials obtained with the process described in the present invention have several immediate technological applications as, for example, for binding of biological molecules like proteins, antigens, antibodies, DNA or RNA fragments, chemicals, active ingredients. Making more functional the particles and/or filaments with biological molecules, allows their usage in diagnostic systems for human or animal health control, as well as for active ingredients delivery systems, in a specific manner for treatment of several diseases.
The use of nanoparticles or nanofilaments, mainly in the health technological sector, has a great action field due to increase the efficiency of active ingredients. Particles can provide a greater specificity when addressing and/or controlling the release of the active ingredient, addressing it to specific organs or cells. In case of the filaments it is possible to associate antibiotics and antiseptics, forming membranes for treatment of burns and wounds.
The present invention is described in detail through the examples presented here. However, it is necessary to stress that the invention is not limited to these examples, but also includes variations and modifications within the limits in which it works. | The present invention relates to a process for producing polymeric structures that have activated surfaces. The process proved to be simple, quick, with high production capacity and low operating costs. The process occurs by depositing a polymer solution, which is assisted by a high electric field, on a conductive liquid surface to produce particles and/or filaments that have an activated surface. More particularly, the process of the present invention has the ability to produce particles and/or filaments that have chemically activated surfaces, in a single process. | 3 |
RELATED APPLICATION
This application claims priority to Application 60/711,576 filed Aug. 26, 2005, entitled CLOSED LOOP ANALOG SIGNAL PROCESSOR “CLASP”, now pending, which is incorporated by reference herein.
FIELD OF THE INVENTION
The present invention relates to sound recording devices in general and, more particularly, to analog tape audio recording devices.
BACKGROUND OF THE INVENTION
Today many, if not most, professional or semi-professional sound, music, or like audio recordings are recorded and produced digitally. In that process, recording engineers typically use an audio digital audio workstation (“DAW”). However, despite the now nearly ubiquitous presence of digital recordings, music, and audio files, many artists, musicians, recording engineers, music producers, and audiophiles still prefer the sound of analog tape recordings over digital recordings because of the warmth and character of the analog tape recordings.
Although there is a desire for the sound of analog recordings, there are a number of limitations that typically discourage any attempt to use a traditional multi track analog tape recording system in combination with a DAW. First, many engineers and producers find that attempting to synchronize a traditional analog tape machine to a DAW to be problematic. For example, some of the problems engineers may encounter when trying to use analog tape machines in conjunction with a DAW include:
(1) Using the Society of Motion Picture and Television Engineers (SMPTE) time code to synchronize the DAW with the tape machine. This sacrifices one of the tape tracks and wastes time waiting for the two devices to synchronize.
(2) Constant rewinding and fast forwarding of the analog tape machine. This takes time away from a session and hurts creative work flow.
(3) Having to transfer the analog tape recorded tracks into the DAW for editing. This is time consuming and breaks the creative work flow.
(4) Big bulky and expensive analog recording machines. Many studios are in people's homes now where space is limited and large format analog recorders are still very expensive.
In short, because of the difficulties of using a standard multi track analog tape recording system with a DAW, many engineers typically resort to using only a DAW to do all of their recording. In other words, engineers and producers sacrifice the warmth and pleasing sound of classic analog tape for the convenient but characterless and thin sound of digital recording.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to allow engineers, music producers, and like personnel to record sounds and music with the character of a genuine analog tape recording. It is also an object of the invention to record music and sounds with the quality of an analog tape recording without the existing hassles and limitations currently involved in using a DAW. It is yet another object of the invention to provide a system and/or components therefore that will allow engineers, music producers, as well as hobbyist, home users, audio enthusiasts, or amateurs to achieve the coveted sound of analog recordings while utilizing at least some of their present studio or recording and processing equipment.
SUMMARY OF THE INVENTION
A system, apparatus, device, and method for recording sounds and music with the character and sonic benefits of a genuine analog tape recording is disclosed. More specifically, an electro-mechanical-software controlled closed loop analog signal processor (“CLASP”) system, which is comprised of a digital audio workstation (“DAW”) resident on a host computer and is in operable communication with a CLASP unit or device and software is disclosed. The CLASP unit, which contains firmware, is also in operable communication with a tape recorder transport which is comprised of a tape mechanism transport and a control unit. In one embodiment, an analog audio signal is recorded on an analog tape, which may be in the form of an endless loop or a reel-to-reel configuration, and then immediately played back and routed to the DAW via an analog to digital converter, thus providing for digitally recorded analog audio. Typically, after the analog recorded signal is played back, it is erased from the tape which generally continues to cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.
FIG. 1 is a schematic drawing of one embodiment of the present invention.
FIG. 2 is a schematic drawing of part of the system shown in FIG. 1 which may be used in an alternative embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates one embodiment of a closed loop analog signal processor (“CLASP”) system 10 of the present invention. As illustrated, the system 10 utilizes a digital audio workstation (“DAW”) 12 resident on a host computer 14 . Examples of DAWs that might be utilized include, but are not limited to, the Pro Tools|HD® systems by Digidesign®, a division of Avid Technology, Inc., located at 2001 Junipero Serra Boulevard, Daly City, Calif. 94014-3886, or Nuendo by Steinberg Media Technologies GmbH. Other DAWs known to those skilled in the art may also be used in accordance with the principles of the present invention. The host computer 14 may be a standard personal computer (“PC”) or a specially made or adapted computer, processor, or workstation. Also, the components and functions of the host computer 14 could in alternative embodiments be spread out, dispersed, or located on multiple machines, and those machines could be located in multiple geographically dispersed locations.
The host computer 14 also contains a machine control 16 which is in operable communication with the DAW 12 and provides control to the host computer 14 . The machine control 16 also allows for a user to interface with the host computer 14 and the DAW 12 software. For example, a user will typically interact with the DAW 12 via the host computers 14 keyboard, mouse, and/or monitor.
As illustrated, the host computer 14 will also typically contains a CLASP driver and software 18 . The CLASP driver software 18 provides a graphic user interface (“GUI”) on the display monitor of the DAW host computer 14 . This GUI typically will show the user both peak and volume unit (“VU”) style level meters for a tape 20 record and playback levels. There will also typically be indicators showing tape 20 usage and calibration settings. Tape 20 speed is also controlled via the software 18 . Other features such as tape 20 noise reduction and variable speed control may also be included. The CLASP driver software 18 will also typically control the monitoring options for the CLASP system 10 . For example, the CLASP driver software 18 will typically allow users to monitor pre-recorded sounds and post-recorded sounds while recording or tracking those sounds. The user will be able to select these, and other features, from a GUI menu. Additionally, the CLASP driver software 18 will allow an artist, musician, or the like recorder to monitor the pre-recorded sounds while the post-recorded analog sounds, which have been converted to a digital signal, are being digitally recorded in the DAW. The CLASP software 18 allows this monitoring to be done with no delay, feedback, or other tape artifacts.
The host computer 14 has an interface 22 to allow it to operably communicate with a corresponding interface 24 in a CLASP unit or device 26 . As illustrated, these interfaces 22 , 24 are firewire ports, but other interfaces, connections, or ports may also be utilized. For example, a Universal Serial Bus (“USB”) port could also be used to operably connect the host computer 14 with the CLASP unit 26 .
While a single CLASP unit 26 is illustrated, in practice, multiple CLASP units 26 may be used together. For example, additional CLASP devices 26 may be added to the system 10 to provide additional tracks per unit. Typically, each CLASP unit 26 will provide eight discrete audio tracks for analog tape signal processing. Accordingly, if a user wanted up to 16 tracks, two CLASP units 26 would be used in unison. Likewise if 24 tracks were desired, three CLASP units 26 would be used. Each CLASP device 26 would be configured to automatically daisy chain together and are thereby in operable communication with the DAW host computer 14 . The CLASP driver software 18 recognizes each unit individually, displays information for each unit 26 , and simultaneously synchronizes all the CLASP devices 26 .
Typically the CLASP unit 26 will be a rack unit or a rack mounted unit, however, it may equally be configured so as to be a stand alone unit, capable of resting on a table, the floor, or other support structure. When rack mounted, each CLASP device 26 is typically housed in a standard nineteen inch rack that utilizes very little space and provides for silent operation. Also, while the DAW host computer 14 and the CLASP unit 24 will generally be located in the same vicinity, like in the same recording studio or room, these components could also be physically separated, either in different parts of a room, different rooms of building, or even in different geographical locations.
The CLASP unit 26 typically includes a CLASP firmware and tape transport control interface 28 . The firmware or microprogram 28 is typically stored in the read only memory (“ROM”) of the CLASP unit 26 . The CLASP unit 24 also typically contains an analog to digital (“A/D”) converter, a digital to analog (“D/A”) converter, various amplifiers 34 , 36 , 38 , a monitoring control 40 , and other components or circuitry known to those skilled in the art. The CLASP unit 26 may also contain a replace tape indicator 42 , however this indicator 42 could also reside in another part of the system 10 , for example in the GUI of the CLASP software 18 on the host computer 14 .
As illustrated, the CLASP unit 26 is in operable communication with a tape recorder transport unit 44 . As illustrated, the tape recorder transport unit 44 is further comprised of a tape mechanism transport 46 and a control unit 48 . The tape recorder transport unit 44 , the tape mechanism transport 46 , and the control unit 48 may be configured as separate components, or may be integrated together. For example the tape recorder transport unit 44 or the tape mechanism transport 46 may be internal or part of the CLASP unit 26 , or may exist as external components, separate and apart from the CLASP unit 26 . In a configurations where the tape recorder transport 44 is an external component, a reel-to-reel multi track tape recorder such as is known to those skilled in the art (e.g., Otari Model No. MTR-90 MKII 2, available at Otari, 4-33-3 Kokuryo-cho Chofu-shi Tokyo 182-0022 Japan, Studer Model No. A-827, available at Studer, Althardstrasse 30 CH-8105 Regensdorf Switzerland, or the like) could be configured to be operably controlled by a Musical Instrument Digital Interface (“MIDI”) machine control protocol, a Sony 9 pin control protocol, or a like control protocol to interface with the CLASP unit 26 .
The tape mechanism transport 46 may be a standard transport mechanism known to those skilled in the art. For example, in one embodiment, the transport mechanism used with a Video Home System (“VHS”) tape might be utilized. In other words, the analog audio tape 20 may be fashioned in a video cassette type of tape cartridge, but the tape will be adapted or formulated for analog or optimal analog audio recording. The tape 20 is typically housed in a removable cartridge for easy tape exchange. Typically, the tape will be a half inch in width, but other sizes may also be used. For example, if a cassette tape format was used, the tape would have a width of about an eighth of an inch. The tape may be in the form of an endless loop 50 cartridge that loops around two reels 52 , 54 , or a standard reel-to-reel 52 a , 54 a cartridge, as shown in FIG. 2 . In embodiments where the tape mechanism transport 46 a uses a non-endless loop tape, an endless tape loop effect may also be achieved by using two or more sets of tapes or tape cartridges. In other words, while one tape was recording or standing by to record, the other tape would be rewinding to allow for it to begin recording when the first tape was full. Multiple tape mechanism transports 46 a would be unitized and synchronized to allow for a seamless recording experience. If a recorded tape was desired to be kept for archival or other purposes, a user may be prompted to replace that tape with a fresh one, while another tape was recording.
The tape mechanism transport 46 has a capstan motor 55 which pulls the tape 20 over the tape heads 56 , 58 and is controlled by the CLASP driver software 18 via standard a MIDI machine control protocol, a Sony 9 pin control protocol, or a like control protocol. Such a protocol is found standard in most all DAW recording systems 12 .
The tape recorder transport unit 44 also has stationary or rotary heads 60 , 62 , 64 which are operationally in contact with the tape 20 . As illustrated, there is a separate record head 60 , playback or reproduction (“repro”) head 62 , and erase head 64 , however, one or more of these heads 60 , 62 , 64 could be configured into a single head. The tape recorder transport unit 44 will also have other components and circuitry known to those skilled in the art.
The control unit 48 , as illustrated, is comprised of a tape transport control and interface 66 and a tape revolution counter 68 . The control unit 48 , and more specifically, the tape transport and interface 66 is in operable communication with the tape mechanism transport 46 . The tape transport control and interface 66 is also in operable communication with the CLASP firmware 28 and provides an interface to and control of the tape mechanism transport 46 . Also, while the control unit 48 is illustrated as a separate component of the tape recorder transport unit 44 , it, or some of its components thereof, could also be located in other places of the system 10 . For example, it or some of its components could also be located in the CLASP unit 26 .
While the drawing illustrates the inclusion of a tape revolution counter 68 is in the control unit 48 , in alternative embodiments, particularly those that do not utilize a closed or endless loop tape configuration, the tape revolution counter 68 may be omitted. Nevertheless, in some embodiments, the tape revolution counter 68 , or like counter, may be still be utilized in non-endless tape configurations to monitor when a tape is nearing its end and/or may need to be replaced. In embodiments that use a closed or endless loop tape 20 , as illustrated, the tape revolution counter 68 monitors the revolutions or rotations of the tape 20 . The tape revolution counter 68 is in operable communication with the CLASP firmware 28 and also with the replace tape indicator 42 . Thus, the input from the tape revolution counter 68 to the CLASP firmware 28 is used to determine when to activate the replace tape indicator 42 . While the drawings illustrate and it is herein described that the tape revolution counter 68 provides this input to the CLASP firmware 28 by counting the number of rotations or revolutions of the tape 20 , other means of determining when the tape 20 should be replaced may also be utilized. For example, a counter could measure the distance the tape 20 has traveled, the amount of time the tape 20 has been in use, the performance of the tape 20 , the time since the tape 20 was last changed, or other like methods of monitoring the potential wear on the tape 20 . Also the CLASP unit 26 may contain a logic circuit that measures how many times the tape 20 passes over the playback and record heads 60 , 62 and tells the user when it is time to replace the tape 20 or clean the tape heads 60 , 62 , 64 and mechanism 46 .
In operation, an incoming analog audio input 70 originates from a microphone or other input source which is adapted to receive, capture, or pickup the sounds desired to be recorded. The analog audio input 70 is then typically routed through the record head amplifier 38 which amplifies the incoming audio signal and passes the signal on to either the stationary or rotary record head 60 which is in operational contact with the tape 20 . After the record head 60 records the analog signal onto the tape 20 , the playback head 62 , located in the illustrated embodiment adjacent to the record head 60 , picks up and reads the recorded signal. The playback head signal is then amplified by the playback or reproduction (“repro”) head amplifier 36 and passes through an analog to the A/D converter 30 . The digital signal is then routed to the DAW 12 located on the host computer 14 . A digitally recorded analog music or sound 72 then results from the DAW 12 .
During operations, the monitoring control 40 also monitors the analog audio input 70 . The monitoring control 40 is in operable communication with the A/D converter 30 and allows a user to thus monitor both the pre-recorded as well as the post-recorded sounds during tracking.
The time delay from the record head 38 to the playback head 40 is calculated and compensated for by computer software communicating with a CLASP software driver 48 running on the DAW host computer 12 . This ensures that CLASP over dubbed tracks are time and phase aligned for playback synchronization. This results in an invisible and seamless analog recording experience because the signals just seem to pass through the CLASP device 26 and onto the DAW 12 hard disk recorder.
In a closed or endless tape embodiment, after the tape 20 passes over the playback head 62 , it then passes over an erase head 64 that erases the audio that was just recorded on that section of the endless tape 20 . The endless loop tape 20 is thus able to be recycled and loop to start the process all over again. Similarly, a non-endless loop tape 20 may also pass over the erase head 64 after the recorded analog audio sound is picked up by the playback head 62 . This may be particularly desirable in embodiments where multiple tapes 20 and multiple tape mechanism transports 46 a are used in conjunction with one another to simulate an endless loop tape effect. Alternatively, the erase head 64 may be positioned to erase the analog audio tape 20 just prior the tape 20 is being re-recorded. In either case, the erase head 64 allows for one tape 20 to be used to record or be standing by to record while another tape 20 is being prepared to record again.
The system 10 uses industry standard MIDI machine control, Sony 9 pin control, or like control, via the CLASP driver software 18 so that the tape 20 is not in motion unless the DAW 12 is operating with record enabled on any given DAW tracks. This helps to prevent unnecessary tape 20 motion when the user is editing or doing any kind of playback that does not involve recording new audio onto DAW tracks. Hence, this helps to extend the life of the tape 20 .
While the present invention has been illustrated by description of various embodiments and while these embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspect is, therefore, not limited to the specific details, representative system, apparatus, and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept. | A system, apparatus, device, and method for recording sounds and music with the character and sonic benefits of a genuine analog tape recording is disclosed. More specifically, an electro-mechanical-software controlled closed loop analog signal processor (“CLASP”) system, which is comprised of a digital audio workstation (“DAW”) resident on a host computer and is in operable communication with a CLASP unit or device is disclosed. The CLASP unit, which contains firmware, is also in operable communication with a tape recorder transport which is comprised of a tape mechanism transport and a control unit. In one embodiment, an analog audio signal is recorded on an analog tape and then immediately played back and routed to the DAW via an analog to digital converter, thus providing for digitally recorded analog audio. Typically, after the analog recorded signal is played back, it is erased from the tape which generally continues to cycle. | 6 |
CROSS REFERENCE TO RELATED APPLICATIONS
This patent application claims the priority and benefit of U.S. provisional patent application 62/360,024, entitled “Firearm Target with Lock On Pattern”, filed on Jul. 8, 2016 and which is incorporated herein by reference in its entirety.
FIELD OF THE EMBODIMENTS
Embodiments are generally related to firearm targets and methods for manufacturing firearm targets.
BACKGROUND
Targets for projectiles have existed since prehistoric times with occasional advances in the art providing targets that are more appropriate for specific uses. Among those advances are printed targets where a target pattern, such as the notoriously familiar bullseye pattern, is printed onto a substrate such as paper, card stock, or plastic. More recently, firearm targets have been developed with frangible or separable ink over a brightly colored substrate for causing the point of impact to be highly visible. The point of impact is highly visible because a separable ink or layer breaks away from the substrate in a ring or halo around the point of impact, thereby revealing a halo of brightly colored substrate material.
U.S. Pat. No. 5,188,371 titled “Reusable Projectile Impact Reflecting Target for Day or Night Use” issued to Edwards on Feb. 23, 1993 and is herein incorporated by reference in its entirety. U.S. Pat. No. 5,188,371 discloses a firearm target having a paper bottom layer colored with a photo-reflective ink, the bottom layer underlying a polypropylene film that is printed with a contrasting ink that contrasts with the photo-reflective ink on the bottom layer. For example, the bottom layer can be bright, even reflective, white, yellow, or orange and the polypropylene can be black. A projectile penetrating the target causes the contrasting ink to separate in an area that is larger than the hole left by the projectile. The reflective ink is thereby exposed and highly visible at the area of projectile's impact. It is for its teaching of targets and targets that show highly visible indications of a projectile's impact point that U.S. Pat. No. 5,188,371 is herein included by reference in its entirety.
U.S. Pat. No. 5,580,063 titled “Reusable Projectile Impact Reflecting Target for Day or Night Use” issued to Edwards on Dec. 3, 1996 and is herein incorporated by reference in its entirety. U.S. Pat. No. 5,580,063 discloses an improvement over Edwards' earlier target which is patented as U.S. Pat. No. 5,188,371. The improvements are in the replacement of certain parts of the target, the reuse of other parts of the target, and improvements directed to the visibility of projectile impact points. U.S. Pat. No. 5,580,063 also provides further disclosures relating to the target itself. It is for its further disclosures and improvements over those of U.S. Pat. No. 5,188,371 that U.S. Pat. No. 5,580,063 is herein included by reference in its entirety.
U.S. Pat. No. 5,501,467 titled “Highly Visible, Point of Impact, Firearm Target-Shatterable Face Sheet Embodiment” issued to Kandel on Mar. 26, 1996 and is herein incorporated by reference in its entirety. U.S. Pat. No. 5,501,467 discloses a target that produces highly visible indications of projectile impact points that is similar to Edwards' targets. It is for it teachings of targets and highly visible impact points that U.S. Pat. No. 5,501,467 is herein included by reference in its entirety.
U.S. Pat. No. 7,631,877 titled “Firearm Targets and Methods for Manufacturing Firearm Targets” issued to Zara on Dec. 15, 2009 and is herein incorporated by reference in its entirety. U.S. Pat. No. 7,631,877 also discloses a target that produces highly visible indications of projectile impact points but with refined layers, gaps in layers, and other improvements. It is for it teachings of refined layers, gaps in layers, and other improvements to targets having highly visible impact points that U.S. Pat. No. 7,631,877 is herein included by reference in its entirety.
The targets described so far provide highly visible indications of a projectiles point of impact. Yet earlier targets were typically light and dark patterns printed directly to a single substrate. None of the prior targets or technologies provide for improvements in aiming. System and methods providing for improvements in aiming at a firearm target are needed.
SUMMARY
The following summary is provided to facilitate an understanding of some of the innovative features unique to the disclosed embodiments and is not intended to be a full description. A full appreciation of the various aspects of the embodiments disclosed herein can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
It is therefore an aspect of the embodiments to provide a firearm target having a substrate. The substrate can be printed with a background in a background color, perhaps with a reflective ink, and then a foreground pattern printed in a foreground color over or aligned to the background. The substrate can be printed with a background pattern and a foreground pattern in a background color and a foreground color, respectively. An alternative is to print the foreground on a separable or frangible layer to thereby provide a target that produces highly visible indications of projectile impact points. Further alternatives can have multiple separable/frangible layers and multiple colors. Yet further alternatives have the background and foreground patterns printed on a separable layer and also in contrasting colors on the substrate.
It is another aspect of the embodiments that the foreground has four trapezoid pairs arranged in a cross pattern having a center point. Each trapezoid pair includes two right trapezoids with each right trapezoid having a long edge perpendicular to a base edge and parallel to a short edge. An angled edge opposite the base edge joins the long edge and the short edge. The intersection of the long edge and angled edge is a pinnacle. The right trapezoids in a trapezoid pair are arranged with their long edges being parallel and separated by a trapezoid separation. Certain embodiments have a trapezoid separation of 5/16 inch or within 1/16 inch of 5/16 inch. The distance can be selected to match the reticle of a rifle scope with some scopes being variable. Therefore, other embodiments can have other trapezoid separation such as ⅝ inch or within 1/16 inch of ⅝ inch. In general, a target has a reticle distance equaling the trapezoid separation when the trapezoid separation is greater than zero. Embodiments can have a trapezoid separation equaling zero in which case the trapezoid pair becomes an obelisk, which is a pointed five sided shape, and the reticle distance equaling the width of the obelisk. The trapezoid pairs and/or obelisks are arranged in a cross pattern with the trapezoid pinnacles (or obelisk points) pointing inward toward the center of the target.
It is yet another aspect of the embodiments that the foreground has four kite shaped wedges, each having a first angled side intersecting a second angled side at a vertex. Certain embodiments have vertices of 34 degrees or vertices within one or two degrees of 34 degrees. An axis bisects the vertex and the wedges are symmetrical along the axis. The wedges can be arranged in a wedge pattern with each vertex at or proximate to the center point of the cross pattern. The axes of two of the wedges can be perpendicular to the axes of the other two wedges. In many embodiments the axes of the wedges are rotated 45 degrees from the cross pattern.
To simplify description herein, some of the target's patterning is described as foreground whereas other patterning is described as background. It is understood that the calling some parts “foreground” and other parts “background” background is a handy but arbitrary labeling target elements. The nomenclature can be changed without changing the appearance of the target.
The foreground and background colors can be specified using color coordinates, as Pantone color numbers, or as colors on a Pantone card. For example, a target having a red foreground and a yellow background can be specified as having a “Pantone card 1.3c Yellow” or pantone 1.3c “process yellow” background and a “Pantone 1795c” foreground. Experimentation has shown that the coated basic process yellow is a good color for many targets. A different target having a yellow foreground and a blue background can be specified as having a “Pantone 311c” background and a “Pantone card 1.3c Process Yellow” foreground.
The “c” after the number (as in 311c or 1795c) or the card number (as in 1.3c) means coated for its brightness so it stands out. It's the contrast and brightness of colors that can make cross hairs in optics stand out for maximum visibility. This way a black cross hair never blends into a black background such as in that of FIGS. 14-16 .
Some embodiments can have a plurality of offset marks. For example, if the wedges are the foreground color, then each wedge can have a square (or diamond or kite or circular or round or elliptical or triangular or polygonal) shaped offset mark in the background color or some other contrasting color.
BRIEF DESCRIPTION OF THE FIGURES
The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the present embodiments and, together with the detailed description of the embodiments, serve to explain the principles of the present embodiments. The figures are not necessarily to scale or full scale.
FIG. 1 illustrates a target having a 5/16 inch trapezoid separation and a reticle distance equaling the trapezoid separation in accordance with aspects of the embodiments;
FIG. 2 illustrates a target having a ½ inch trapezoid separation and a reticle distance equaling the trapezoid separation in accordance with aspects of the embodiments;
FIG. 3 illustrates a right trapezoid in accordance with aspects of the embodiments;
FIG. 4 illustrates a target having a ⅝ inch trapezoid separation and a reticle distance equaling the trapezoid separation in accordance with aspects of the embodiments;
FIG. 5 illustrates a target having a ¾ inch trapezoid separation and a reticle distance equaling the trapezoid separation in accordance with aspects of the embodiments;
FIG. 6 illustrates a target having a ⅞ inch trapezoid separation and a reticle distance equaling the trapezoid separation in accordance with aspects of the embodiments;
FIG. 7 illustrates a target having a 1 inch trapezoid separation and a reticle distance equaling the trapezoid separation in accordance with aspects of the embodiments;
FIG. 8 illustrates a target having a 0 inch trapezoid separation and a 5/16 inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments;
FIG. 9 illustrates a target having a 0 inch trapezoid separation and a ½ inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments;
FIG. 10 illustrates a target having a 0 inch trapezoid separation and a ⅝ inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments;
FIG. 11 illustrates a target having a 0 inch trapezoid separation and a ¾ inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments;
FIG. 12 illustrates a target having a 0 inch trapezoid separation and a ⅞ inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments;
FIG. 13 illustrates a target having a 0 inch trapezoid separation and a 1 inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments;
FIG. 14 illustrates a target having a 0 inch trapezoid separation, a 5/16 inch cross thickness, and a center structure such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments; and
FIG. 15 illustrates a target having a 0 inch trapezoid separation, a 3/16 inch cross thickness, and a center structure such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments; and
FIG. 16 illustrates a target having a 0 inch trapezoid separation, a ¼ inch cross thickness, and a center structure such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments.
DETAILED DESCRIPTION
The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.
The embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the embodiments are shown. The embodiments disclosed herein can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the embodiments to those skilled in the art. Like numbers refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
FIG. 1 illustrates a target 100 having a 5/16 inch trapezoid separation 103 and a reticle distance equaling the trapezoid separation 103 in accordance with aspects of the embodiments. Four trapezoid pairs 102 having two right trapezoids 101 are arranged in a cross pattern marked as element 201 in FIG. 2 . The target 100 also has four wedges 106 having a first angled side 110 , a second angled side 111 , and a vertex 105 that is the angled tip between the first angled side 110 and the second angled side 111 . An axis 112 bisects the vertex. The axis 112 is illustrated as a line bisecting a vertex 105 , but such a line is not visible in all embodiments. Each leg of the cross pattern 201 has a cross thickness 104 equaling the trapezoid separation 103 plus two of the base lengths of the right trapezoid. The base lengths are the lengths of elements 302 in FIG. 3 below. Each of the wedges 106 has an offset mark 107 centered on the axis 112 .
Target 100 has a foreground 109 that can be blaze orange, fluorescent orange, or red such as the red specified as “Pantone 1795c.” Target 100 also has a background 108 that can be in a color that contrasts well with the foreground color. For example, “Pantone card 1.3c Yellow” contrasts well with “Pantone 1795c.” Another example would have a black foreground and white background while yet another example would have a white foreground and a black background.
Target 100 has grid lines 113 arranged in a grid. The illustrated grid lines 113 are black. The black gridlines 113 are visible against both the foreground color and the background color. If the gridlines 113 illustrated in FIG. 1 are spaced by one inch, then target 100 is approximately 12 inches by 12 inches and the illustrated offset marks 107 would be approximately two inches in from each edge. The measurements become important because a reticle distance of 5/16 inch is well suited for sighting in a scoped rifle at 100 yards because the reticle of many scopes is sized to almost completely obscure the space between the right trapezoids of each trapezoid pair. A marksman aiming at the target is therefore able to “lock on” the target by almost or completely blanking out that space, based on marksman preferences. Slight offsets from the ideal lock on position are highly visible because strips of bright contrasting color appear in the marksman's sight image. This enables a shooter the ability to lock on and keep crosshairs on the center point of the target without wavering. Increased accuracy and ability can improve with repetitive use of the targets, thereby increasing skill levels.
The target having the 5/16 inch trapezoid separation and a reticle distance equaling the trapezoid separation can also work well for 50 yard distances for low power scopes such as a four power scope or variable power scope set to lower power. Similarly, a larger reticle distance, such as ½″ or even larger can be used by lower power scopes at longer ranges such as 100 yards or 200 yards. The key is matching the target's reticle distance to the thickness of the scope's crosshairs at the distance being shot at. Furthermore, a variable scope can be adjusted to achieve optimal blanking of the lock on pattern.
Most reticles are black with the exception of certain reticles such as illuminated reticles. For constant reticle visibility, the foreground and background colors are ideally selected to contrast with the reticle color as well as with each other. It is for this reason that yellow, red, and blue have been selected as example foreground and background colors because they contrast with a black reticle.
The shapes of the wedges 106 are designed to guide the marksman's eye to the center of the target and into the ideal locked on position where the scope reticle completely or almost completely blanks the background color strips running down the center of each leg of the cross pattern. Recall that each leg of the cross pattern is a trapezoid pair. Experimentation has shown that wedges having a 34 degree angle at the vertex produce excellent results.
The offset marks 107 can be used by a marksman to test the mechanics of a firearm scope. Firearm scopes and their reticles are notoriously well known to those who enjoy, build, market, or repair firearms. A firearm scope is an optical sighting/aiming aid typically using lenses to magnify the image of a target and to display a reticle over top of the target. Returning now to the embodiments, a sighted in firearm should reliably place shots in the middle of the target at the center 202 . Assuming that target 100 is 12″×12″, the offset marks are four inches in each direction from the target center 202 . If a scope has “½ inch clicks,” then a marksman can enter eight clicks right, eight clicks up, aim at the target center, pull the trigger, and hit the top right offset mark. By then, entering sixteen clicks left and shooting for the target center, the marksman hits the top left offset mark. It is by entering clicks into the scope and observing projectile impacts that a marksman can determine how well the mechanisms within the scope are operating.
The foreground and background colors can be specified using color coordinates, as Pantone color numbers, or as colors on a Pantone card. For example, a target having a red foreground and a yellow background can be specified as having a “Pantone card 1.3c Yellow” background and a “Pantone 1795c” foreground. A different target having a yellow foreground and a blue background can be specified as having a “Pantone 311c” background and a “Pantone card 1.3c Yellow” foreground. Yet other embodiments can have a “Pantone card 1.3c Yellow” foreground and a highly contrasting background such as “Pantone 311c” blue. Note that “Pantone card 1.3c Yellow” is also known as “Pantone card 1.3c Process Yellow”.
FIG. 2 illustrates a target 200 having a ½ inch trapezoid separation 103 and a reticle distance equaling the trapezoid separation 103 in accordance with aspects of the embodiments. Four trapezoid pairs 102 form a cross pattern 201 having a center 202 .
FIG. 3 illustrates a right trapezoid 101 in accordance with aspects of the embodiments. The right trapezoid 101 has a long side 301 , base 302 , short side 303 , and angled side 304 . The base 302 has a length here called the base length. The long side 301 and the angled side 304 meet at a pinnacle 305 . In the embodiments illustrated herein, the pinnacle is the point on the right trapezoid that is closest to the center 202 .
FIG. 4 illustrates a target 400 having a ⅝ inch trapezoid separation 103 and a reticle distance equaling the trapezoid separation 103 in accordance with aspects of the embodiments. Recall that the ⅝ inch trapezoid separation (plus or minus printing tolerances and minor deviations) provides an optimal reticle distance for many scopes at a 100 yard distance, particularly lower powered optics such as, for example, fixed four power scopes or 1×-5× variable scopes. In addition, different scopes can have different thickness reticles depending on manufacturer or manufacturer's model.
FIG. 5 illustrates a target 500 having a ¾ inch trapezoid separation 103 and a reticle distance equaling the trapezoid separation 103 in accordance with aspects of the embodiments.
FIG. 6 illustrates a target 600 having a ⅞ inch trapezoid separation 103 and a reticle distance equaling the trapezoid separation 103 in accordance with aspects of the embodiments.
FIG. 7 illustrates a target 700 having a 1 inch trapezoid separation 103 and a reticle distance equaling the trapezoid separation 103 in accordance with aspects of the embodiments. Notice that in this non-limiting example, the offset marks 107 appear approximately one inch square and that certain grid lines 113 appear to bisect the right trapezoids 101 along their long axis. The size of the offset marks 107 does not need to match the reticle distance 103 . For example, 1 inch square offset marks 107 may be on a ⅝ inch reticle distance target. As a further generalization, the offset marks 107 do not have to be centered on the target diagonals, on the axes of the wedges 112 , or two inches from the target sides. It is preferable, however, that the number of scope “clicks” from the center 202 to the offset mark 107 is easy to calculate. As such, it may be better for offset marks 107 to be offset from the target center 202 by an integer number of inches.
FIG. 8 illustrates a target 800 having a 0 inch trapezoid separation and a 5/16 inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments. Here, the “lock on” principal is somewhat altered in that the reticle blanks, or nearly blanks, the entire cross pattern. The word “blank” is understood to mean obscures, hides, or completely overlays. Some marksmen prefer for the reticle to completely blank the cross pattern of this embodiment or the centers of the cross patterns of the embodiments of FIGS. 1-2 and 4-7 . Other marksmen prefer nearly blanked over fully blanked.
FIG. 9 illustrates a target 900 having a 0 inch trapezoid separation and a ½ inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments.
FIG. 10 illustrates a target 1000 having a 0 inch trapezoid separation and a ⅝ inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments.
FIG. 11 illustrates a target 1100 having a 0 inch trapezoid separation and a ¾ inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments.
FIG. 12 illustrates a target 1200 having a 0 inch trapezoid separation and a ⅞ inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments.
FIG. 13 illustrates a target 1300 having a 0 inch trapezoid separation and a 1 inch cross thickness such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments.
FIG. 14 illustrates a target 1400 having a 0 inch trapezoid separation, a 5/16 inch cross thickness, and a center structure 1401 such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments. The embodiment illustrated in FIG. 14 does not show the points of the obelisks because the center structure is at the center of the target. This can be achieved by, for example, overlaying the center structure over the obelisk points and therefore hiding the obelisk points. Target 1400 is similar to targets 800 , 900 , 1000 , 1100 , 1200 , and 1300 excepting that target 1400 does not have offset marks, but does have a center structure 1401 . The center structure is four kite shapes, each approximately as thick as or slightly thicker than the cross thickness and meeting at the center 202 . The foreground can be in a yellow color such as “Pantone card 1.3c Yellow” while the background is black. The center structure can be in a third color such as blaze orange. The grid lines can be in a fourth color such as a green color that is visible against both a yellow foreground and a black background. Note that the centermost gridlines of other illustrated embodiments are not present in the embodiment of FIG. 14 and, as such, the center structure is not overlaid with a grid line.
FIG. 15 illustrates a target 1500 having a 0 inch trapezoid separation, a 3/16 inch cross thickness, and a center structure 1401 such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments.
FIG. 16 illustrates a target 1600 having a 0 inch trapezoid separation, a ¼ inch cross thickness, and a center structure 1601 such that each trapezoid pair becomes an obelisk and the reticle distance equals the cross thickness in accordance with aspects of the embodiments.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. | A firearm target is specially adapted for the purpose of sighting in a scoped firearm. The scope has a reticle with horizontal and vertical lines forming crosshairs. The target has a cross pattern in contrasting colors with a cross shaped gap. The gap is highly visible and may even be in a reflective color. The gap size is selected to match the crosshair thickness and the targeting distance. Aligning the crosshairs to the gap significantly or completely hides the gap. Misaligning the crosshairs to the gap causes the gap to become more visible because of the gap's highly noticeable and contrasting colors. The target thereby provides a lock-on functionality for a marksman. | 5 |
BACKGROUND OF THE INVENTION
[0001] 1. Statement of the Technical Field
[0002] The inventive arrangements relate generally to the field of resistors, and more particularly to resistors integrated into a substrate.
[0003] 2. Description of the Related Art
[0004] Thick-film resistors are commonly employed in hybrid electronic circuits to provide a wide range of resistor values for use on printed circuit boards (PCBs), in flexible circuits, or on ceramic or silicon substrates. Such resistors are typically formed using deposition techniques known in the art, for example using a thick film screen printing process to deposit a resistive ink, or paste, on a substrate. Resistive thick-film inks are typically composed of an electrically conductive material, typically a Metal Oxide, along with glass frit components, disposed in an organic vehicle or polymer matrix. Further, various additives are typically used to adjust the electrical properties of the inks. After printing, the thick-film ink is typically heated to dry the ink and convert it into a suitable film that adheres to the substrate. The heating process also burns off the organic vehicle, sinters the metal and glass components and/or cures the polymer matrix material.
[0005] Compared to many other deposition processes, screen printing is a relatively crude process. Conventional screen printing techniques generally employ a template, referred to as a screening mask, with apertures bearing the positive image of the resistor to be created. The template is usually placed above and in close proximity to the surface of the substrate on which the resistor is to be formed. The mask is then loaded with the resistive ink, and a squeegee blade is drawn across the surface of the mask to press the ink through the apertures and onto the surface of the substrate. Accordingly, control of the width, length and thickness of the resistor during the screen printing process is particularly challenging and resistor dimensions can vary significantly.
[0006] Since the electrical resistance of a thick-film resistor is dependent on the precision with which the resistor is produced, it is particularly difficult to fabricate thick-film resistors having close tolerances. Moreover, the control of resistor width, length, and thickness is fundamentally limited by the relatively coarse mesh of the screening mask and by ink flow after deposition. Hence, screen printed thick-film resistors are typically limited to dimensions of about one millimeter, which is larger than many chip resistors. Consequently, as-fired thick-film resistor tolerances are usually limited to approximately 20% to 30%. Thick-film resistors can be laser trimmed to improve resistance tolerances, but laser trimming adds cost, requires additional surface area and may require keep out zones on the layers below the resistor, all of which hinders miniaturization of electronic circuits.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a circuit board substrate with integrated resistive components and a method of manufacturing the same. A rigid substrate board is provided having at least one layer with first and second opposing surfaces. At least one bore is formed in the layer, extending from the first surface to the second surface. A resistive material is disposed within the bore and fills the bore to form a resistor. A first conductor is then disposed on the first surface to form an electrical connection with a first end of the resistor, and a second conductor disposed on the second surface to form an electrical connection with a second end of the resistor.
[0008] A plurality of the resistors can be formed in the layer and interconnected to define a resistive network. The first conductor can electrically connect the first end of the first resistor to an end of at least a second resistor exposed at the first surface. The second conductor can electrically connect the second end of the first resistor to an end of a third resistor exposed at the second surface. Further, a third conductor can be disposed on the first surface to form an electrical connection with at least a second end of the third resistor.
[0009] A second layer can be disposed on the first surface and at least one bore can be formed the second layer. The bore can extend from a third surface to a fourth surface defining opposing sides of the second layer. A conductive material can be disposed within the bore to provide an electrical connection to one or more of the resistors on the first layer. Further, a resistive material can be disposed within the bore to provide a resistor in series with one or more of the resistors on the first layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIGS. 1 A- 1 C are a series of cross sectional views showing a method of forming vias in a substrate in accordance with the present invention.
[0011] [0011]FIG. 2 is a cross sectional view of a substrate cross section wherein the substrate includes buried resistors in accordance with the present invention.
[0012] [0012]FIG. 3 is a flow chart of a method of manufacturing buried resistors in a substrate in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] The present invention provides a substrate having resistors formed within vias in a substrate and more particularly in a circuit board substrate. The resistors can be connected in series and in parallel to attain desired resistance values. Notably, since the resistors are formed within the substrate, a greater amount of substrate surface area is available for positioning of other components. Moreover, the size of a substrate can be reduced since area that would normally be used by surface mounted resistors is no longer required.
[0014] Significantly, the resistors formed within vias can be manufactured with much higher tolerances than other types of compact resistors. Higher manufacturing tolerances can be maintained because the diameter of vias and the thickness of the substrate can be accurately controlled. Hence, costly processes that are sometimes used to adjust resistor values, such as laser trimming, can be avoided. Moreover, since resistors formed within vias only contact the substrate at the via perimeter, interactions between the resistors and the surrounding substrate are minimized. Further, print quality and accuracy of conductor placement will have an insignificant impact on resistor tolerances. Accordingly, resistors formed within substrate vias can be manufactured more economically and with better quality than other types of low tolerance resistors.
[0015] Referring to FIG. 1A, a cross-sectional view is shown of a substrate. The substrate includes a first substrate layer 105 having opposing surfaces 106 , 107 . The first substrate layer 105 can be formed from any substrate material wherein vias can be formed. For example, the substrate can be formed from ceramic material, such as low temperature co-fired ceramic (LTCC), or a semiconductor material, such as silicon or germanium. Nonetheless, the invention is not so limited and other substrate materials can be used.
[0016] One or more vias 110 can be formed by creating bores which extend through the first substrate layer, thereby defining a first opening 108 in the first side of the first substrate layer and a second opening 109 in the second side of the first substrate layer. Many techniques are available for forming bores in a substrate layer. For example, in some substrates, such as ceramic substrates, bores can be formed by laser cutting holes through the substrate or mechanically punching the holes. In other substrates, for example silicon, bores can be etched into the substrate layer using known etching techniques. In a preferred arrangement, the tolerance of the cross-sectional area of each via is tightly controlled.
[0017] The vias can be formed so that each via has a same cross sectional profile, or the size of the vias can be selectable so that each via has an optimum cross sectional area to achieve a desired resistance value once the vias have been filled. Vias also can be overlapped to form a larger via with an increased cross sectional area. Further, vias can be formed to have any desired shape. For instance, a via can be formed to have a cylindrical wall profile to maintain a constant cross sectional area throughout the length of the via, or a trapezoidal wall profile can be used to vary the cross sectional area over the length of the via.
[0018] After the vias 110 have been formed, they can be filled as shown in FIG. 1B with a material 104 having electrically resistive characteristics (resistive material) to form buried resistors 140 . For example, the buried resistors can be formed to have resistance values ranging from under 10 Ω to over 100 MΩ. The resistive material can be any material having electrically resistive properties and that can be used to fill a via. In one arrangement, a solid resistive material, for example a carbon based resistive material, can be formed in the shape of cylinders that fit into vias 110 . In another arrangement, a paste, liquid or semi-liquid resistive material can be used to fill the vias 110 . For example, the resistive material can be a ruthenium oxide (RuO 2 ) based resistive material. The use of RuO 2 as a resistive material is known to the skilled artisan and has shown to exhibit superior resistor properties, such as electrical and mechanical stability as well as resistance to environmental elements, such as humidity. RuO 2 is commonly used in thick film inks that are made for printing resistors onto a surface, but such inks tend to shrink at a rate disproportionate with the substrate material shrink rate when the inks are dried. However, proportions of solids, vehicles and fillers in the resistive material, for example glass fillers, can be adjusted to modify the shrink rate of the resistive material. Component particle size can also be selected to achieve desired shrinkage characteristics. Accordingly, the shrink rate can be customized to match the shrink rate of the substrate.
[0019] Characteristics of resistive material can be used to adjust its resistivity. For example, the characteristics of RuO 2 can be modified in the resistive material. Accordingly, the resistivity can be adjusted to result in a buried resistor having any standard resistor value. Further, resistivity can be adjusted to result in custom resistance values, for example, 25.4 kΩ or 1.65 MΩ.
[0020] Referring now to FIG. 1C, one or more conductors 115 can be deposited on the top of the first substrate layer over the top of the vias 110 , making electrical contact with the buried resistor 140 . Further, one or more conductors 120 can be deposited on the bottom of the first substrate layer, under the bottom of the vias 110 , also making electrical contact with the buried resistor 140 . The conductors can be formed of any suitably conductive material. For example a metal or metal alloy can be used for this purpose. Techniques for deposition of such conductors are well known in the art. Notably, if the conductors 115 , 120 are disposed so that the top conductor 115 contacts the entire top surface 145 of the buried resistor 140 , and the bottom conductor 120 contacts the entire bottom surface 150 of the buried resistor 140 , the resistor's current carrying capability can be maximized.
[0021] Referring now to FIG. 2, it can be seen that the conductors 115 can alternatively be deposited on a bottom side of a second substrate layer 205 and positioned so that the conductors 115 make electrical contact with the buried resistors 140 when the first substrate layer 105 and second substrate layer 205 are joined together. Likewise, the conductors 120 can be deposited on a top of a third substrate layer 230 , if provided, and positioned so that the conductors 120 make electrical contact with the buried resistors 140 when the first substrate layer 105 and third substrate layer 230 are joined together. Notably, the third substrate layer 230 is not required and the conductors 120 can remain exposed for device connections to the bottom surface 107 of the first substrate layer 105 .
[0022] Various methods can be used to join the substrate layers. For example, the layers can be laminated together using a variety of lamination methods. In one method using ceramic substrate layers, the substrate layers can be stacked and hydraulically pressed with heated platens. For example, a uniaxial lamination method presses the ceramic substrate layers together at 3000 psi for 10 minutes using plates heated to 70° C. The ceramic substrate layers can be rotated 180° following the first 5 minutes. In an isotatic lamination process, the ceramic substrate layers are vacuum sealed in a plastic bag and then pressed using heated water. The time, temperature and pressure can be the same as those used in the uniaxial lamination process, however, rotation after 5 minutes is not required. Once laminated, the structure can be fired inside a kiln on a flat tile. For example, the ceramic substrate layers can be baked between 200° C. and 500° C. for one hour and a peak temperature between 850° and 875° can be applied for greater than 15 minutes. After the firing process, post fire operations can be performed on the ceramic substrate layers.
[0023] The conductors 115 and conductors 120 can be positioned so that they provide an electrically continuous connection between two or more buried resistors 140 . For example, the conductors can be arranged as shown in FIG. 2 to connect a plurality of buried resistors 140 in series and/or in parallel to form a resistor circuit. Accordingly, if the buried resistors 140 each have a particular nominal value, they can be connected in parallel to achieve lower values, or in series to achieve higher values. Further, series and parallel buried resistor combinations can be used to achieve other desired resistance values, for example multiple resistors can be combined in resistor circuits having both series and parallel combinations. This method has an advantage over a method wherein a different resistive filler is mixed for each individual resistor value, especially if a particular circuit incorporates a wide range of resistor values. Notably, it is much less time consuming and much more cost effective to apply a single resistive filler to a substrate than to mix a wide range of resistive filler mixtures. Moreover, the risk of an incorrect resistive filler being applied to a via is reduced when all of the vias are filled with the same resistive filler.
[0024] Vias can also extend through the second substrate layer 205 or third substrate layer 230 . For example, in FIG. 2 vias 210 are shown in the second substrate layer 205 . The vias 210 can be filled with a resistive material 220 of a same or different resistivity, as described above relative to vias 110 . For example, vias 210 in the second substrate layer 205 can be filled with a resistive material to form 1 kΩ resistors while the first substrate layer 105 is filled with a different resistive material which is used to form 100 kΩ resistors. Further, the thickness of the second substrate layer 205 and/or the third substrate layer 230 can be different than the thickness of the first substrate layer 105 . Accordingly, length of the buried resistors can be varied between layers to provide another method of controlling resistance values. For example, the second substrate layer 205 can be 50% thicker than the first substrate layer. Assuming that a second via in the second substrate layer 205 has the same cross sectional area as a first via in the first substrate layer 105 , and that the first and second vias are filled with the same resistive material to form buried resistors, the buried resistor formed in the second via will have a resistance that is approximately 50% higher than the buried resistor formed in the first via.
[0025] In lieu of being filled with resistive material, the vias 210 also can provide a path for a conductor 215 . For example, a conductive coating can be deposited on the walls of the vias 210 , conductive pins can be inserted through the vias 210 , or the vias can be filled with a conductive material, as would be known to the skilled artisan. Further, conductors 225 can be deposited on a top side of the third substrate layer, thereby providing an electrical contact with the conductors 215 or resistor(s) 220 in the vias 210 . Thus, the conductors 215 and/or resistor(s) 220 can be used to provide an electrically continuous connection between the conductors 225 and the conductors 115 . Accordingly, the conductors 215 and/or resistor(s) 220 can be arranged to provide multiple taps from the resistive circuit, thereby providing a variety of resistance values from a single resistive circuit.
[0026] A method 300 of manufacturing buried resistors in a substrate is shown in FIG. 3. Referring to step 305 , substrate layers can be preconditioned before being used in a fabrication process. For example, if the ceramic substrate material is used, the substrate can be baked at an appropriate temperature for a specified period of time or left to stand in a nitrogen dry box for a specified period of time. Common preconditioning cycles for ceramic material are 120° C. for 20-30 minutes or 24 hours in a nitrogen dry box. Both preconditioning process are well known in the art of ceramic substrates.
[0027] Referring to step 310 , one or more bores can be created in each of the substrate layers 105 , 205 , 230 that are to incorporate vias. As previously noted, many techniques are available for forming bores in a substrate layer, such as mechanically punching, laser cutting, or etching holes into the substrate layer. The bores or vias can then be filled with a resistive material using a mylar or metal mask and a printing process to form buried resistors as shown in step 315 . In one arrangement, vacuum can be applied to the first substrate layer through a porous stone to aid via filling.
[0028] Referring to step 320 , the resistive material then can be dried. For example, a drying process can include baking the first substrate layer at 120° C. for 5 minutes. If the resistive material has a greater shrinking coefficient than the substrate material in the substrate layers, thereby leaving some empty space in the vias after drying, additional resistive material can be added to the vias to fill the empty space. The substrate layers can again be baked. This process can be repeated until the vias are completely filled with resistive material to form the buried resistors. At this point conductive material can be added to vias which are selected to be conductive vias. For example, a solid conductor can be inserted into the selected vias.
[0029] Referring to step 325 , conductive layers then can be deposited on the first substrate layer 105 , the second substrate layer 205 , and/or the third substrate layer 230 . For example, a conventional thick film screen printer, such as a standard emulsion thick film process, can be used to deposit conductive layers on the desired substrate layers. The substrate layer(s) then can be baked to dry the conductive traces, as shown in step 330 , for example at 120° C. for 5 minutes for LTCC.
[0030] Referring to step 335 , the second and third substrate layers 205 and 230 can be laminated to the first substrate layer 105 after appropriate preconditioning and drying of circuit traces. A variety of techniques for laminating substrates are known to those skilled in the art of substrate manufacturing, as previously discussed. The laminated substrate structure then can be sintered, as shown in step 340 . For example, in the case that the substrate is LTCC, the first and second substrate layer combination can be sintered at approximately 850° C. to 900° C. for 15 minutes.
[0031] While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as described in the claims. | A rigid substrate board ( 105 ) having at least one layer with first ( 106 ) and second ( 107 ) opposing surfaces. At least one bore is formed in the layer and extending from the first surface ( 106 ) to the second surface ( 107 ). A resistive material is disposed within the bore and fills the bore to form a resistor ( 140 ). Further, a first conductor ( 115 ) is disposed on the first surface ( 106 ) to form an electrical connection with a first end of the resistor ( 140 ), and a second conductor ( 120 ) is disposed on the second surface to form an electrical connection with a second end of the resistor. A plurality of resistors ( 140 ) can be formed in the substrate layer ( 105 ) and interconnected to define a resistive network. | 8 |
FIELD OF THE INVENTION
This invention relates to a circuit arrangement for protecting couplings which involves monitoring the slip of an overload coupling or clutch between a driving machine element and a driven, rotating machine element. The invention is concerned more particularly with such a circuit arrangement utilizing a contactless rotational speed pulse generator element on each part of the clutch and a pulse comparator connected downstream thereof.
BACKGROUND OF THE INVENTION
In operation, overload couplings or clutches of the kind considered here tend to slip when overloaded, that is to slip when the torque is increased to an impermissible great extent. Overload clutches of this kind are provided for the protection of machines or machine parts particularly when a powerful driving unit must work against considerable counterforces; if locking occurs in the working machine as the result of a breakdown, either the working machine may be destroyed through overload or the driving unit may be damaged by running at high speed without load. This problem occurs particularly in screw machines such as extruder machines, in which the circuit arrangement of the invention finds its preferred application.
Although commercial slip indicators exist, which in principle are also suitable for the task of monitoring overload clutches, it has nevertheless been found that these known devices either react to a deviation from zero slip or else respond only at comparatively high slip values. Both of these response limits are unsuitable for the preferred application of the invention. It has in fact been found that overload clutches suitable for extruder machines have a continuous slight operating slip which leads to a kind of self-cleaning effect to which the accurate and reliable response of the overload clutch when subjected to overload is attributable. If they were adjusted to zero slip the available devices would therefore continuously bring about overload release even during operation under normal conditions, although there would actually be no justification for this, whereas on the other hand the adjustable value of slip other than zero is already so great that because of the powerful driving forces the heat generated in the overload clutch would lead to destruction of the clutch.
It has already been attempted to produce slip monitoring circuits which work with greater sensitivity, these being based on the counting of pulse transmissions from each of the two parts of the clutch; when there is no slip, each pulse transmission from the driving part of the clutch is followed by a pulse tramsmission from the driven part of the clutch which neutralizes this first pulse transmission. When slip occurs, the second, compensating pulse is increasingly retarded until finally another pulse from the driving part of the clutch arrives before the arrival of the compensating pulse, so that the compensating part of the clutch, which acts after the driving part, will compensate only one of the two first pulses. These pulse transmissions are converted into a voltage level, and a subsequent voltage level or voltage difference evaluation initiates the monitoring or check signal for indicating impermissibly high slip. It has however been found that even with slip monitoring circuits of this kind the required sensitivity of response, which has to be asked of the circuit arrangement because of the comparatively low operating slip extending up to about 0.12%, cannot be achieved. One important reason for this is that, because of manufacturing and functional tolerances of these circuit arrangements based on voltage difference measurement, the necessary accuracies cannot be permanently maintained when operating with extremely low permissible slip.
SUMMARY OF THE INVENTION
It is another object of the present invention to provide a circuit arrangement for protecting a coupling which effects a decoupling only when slip exceeds zero slip by a predetermined value.
It is another object of the present invention to provide a circuit arrangement for protecting a coupling which effects a decoupling upon the occurrence of slip less than that which would damage the coupling or driver machine element and yet exceeds zero by a given value.
According to the present invention, there is provided a circuit arrangement for protecting an overload coupling between a driving machine element and a driven, rotating machine element, comprising means for monitoring the slip of the coupling, including a respective contactless rotational speed pulse generator element associated with two parts of a clutch. A pulse comparator is provided to which the output of each pulse generator is connected. The pulse comparator is a forward-backward counter to whose forward and backward counting inputs is supplied respectively, the outputs from the pulse generators, and to whose reset input a time base stage is connected. The counting result output of the counter is fed to a decoding stage which responds to a predetermined minimum counting result and which operates a signal generator.
For the economical construction of a circuit arrangement of this kind it is desirable to be able to use forward-backward counters of a simple type, that is to say inexpensive devices. The simple counters however have the disadvantage that between operation in the forward counting direction and operation in the backward counting direction a certain switching time must always elapse, and it is precisely with low slip that the signals are transmitted by the two parts of the clutch in extremely close succession. Furthermore, in the case of greater slip or when the two parts of the clutch accidentally assume a certain position in relation to one another it may even happen that the two pulse transmissions overlap. In order nevertheless to ensure reliable operation of a counter which can be operated forwards or backwards only at certain intervals of time, in a further feature of the invention a two-channel decoupling circuit is provided. This circuit ensures that only the first pulse initiated by a clutch part which occurs first will set directly on the counter for forward or backward counting, but that the following pulse is not lost but in turn acts on the counter after the first pulse has had its effect.
According to a further feature of the invention, additionally to the measures mentioned above and which will be described in detail below, at least one timing element bridging the two-channel decoupling circuit and the counter is provided, this timing element preventing the machine protected by the overload clutch from being put into operation if by mistake the circuit connection of the invention has not been connected to the overload clutch. This timing element may also serve as a rotational speed monitor ensuring that after disconnection of the overload clutch as the result of impermissibly increased slip, the driving part of the machine is recoupled to the driven part only when the relative rotational speed between these two parts of the machine has become sufficiently low.
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE of drawing is a schematic illustration of an overload clutch, which can be considered a slip coupling, between two shaft ends, serving, respectively, as driving and driven machine elements, together with a preferred example of a circuit arrangement according to the present invention, shown as a clock diagram.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in the drawing figure, a geared motor 1 drives a rotationally driven working machine in which the rotary drive is opposed by considerable counterforces, for example the screw press of an extruder machine 2. In order to protect the geared motor 1, but in particular to protect the extruder machine 2, force is transmitted between the driving shaft end 3 and the driven or output shaft end 4 by way of an overload clutch 5. Overload clutches of this kind are usually in the form of slipping clutches, that is to say when the torque acting on the clutch surface becomes excessive because of the blocking of the extruder machine 2, the overload clutch 5 will slip in order to protect the extruder machine 2 from damage. This slipping of the overload clutch 5 also provides the advantage that the geared motor 1 cannot be braked to a standstill by the overload - a method of operation which would also entail the danger of damage to the geared motor 1.
Commercially available overload clutches of the kind considered here usually have in normal operation a certain slip which serves in particular for the self-cleaning of the opposing clutch surfaces. In overload clutches, of the type particularly useful, the clutches 5, which have been produced in practice this operating slip may amount to up to about 0.12%. If in consequence of the blocking of the extruder machine 2 the overload clutch 5 should slip completely because its driven clutch part, which is rigidly joined to the driven shaft end 4, is stationary, while the clutch part is rigidly joined to the driving shaft end 3 continues to be turned by the geared motor 1, the entire driving energy in the frictional surface between the two parts of the clutch must be absorbed. In consequence of the considerable generation of heat between the two parts of the clutch, this operating state, in which the overload clutch 5 has thus responded, usually leads rapidly to the destruction of the overload clutch 5. This entails the disadvantage that not only must the extruder machine 2 now be cleared out before being put back into operation, but that in particular a new overload clutch 5 has to be installed between the shaft ends 3 and 4.
The circuit arrangement according to the invention for protecting the overload clutch 5 serves to prevent the destruction of the responding overload clutch 5 by continuous monitoring of the slip of the overload clutch 5.
The instantaneous slip is measured in a digital counter 6 adapted to be selectively operated forward or backwards. Each of the two counting inputs to the counter 6 is operated by an associated part of the overload clutch 5, and in the illustrated embodiments the forward counting input 7 is operated by the clutch part connected to the driving shaft end 3, and the backward counting input 8 is correspondingly operated by the clutch part connected to the driven shaft end 4. Each of the two clutch parts is equipped with a preferably contactless rotational speed pulse transmitter element 9.1 and 9.2 respectively. In a manner known per se, this may involve optical, ferromagnetic, or other sensing of the rotation of the clutch parts. The drawing shows an embodiment utilizing respective metal lugs which are fastened to a clutch part and which on passing through the associated pulse transmitter element 9.1 or 9.2 respectively, initiates the transmission of a pulse. Particularly in the case of a low rotational speed of the shaft ends 3 and 4, it may be expedient to generate by suitable means a plurality of pulses for each rotation of a clutch part, for example, by providing a pluraity of angularly offset metal lugs on the clutch parts. Multiple pulse transmission for each revolution in this manner increases the accuracy of measurement. In the interest of simpler evaluation of signals it is expediently ensured by corresponding reciprocal arrangements that the two clutch parts produce an equal number of pulses for a revolution, with the same relative time displacement.
A problem is that simple forward-backward counters, such as the counter 6, can process at the same time only either a control pulse acting in the counting direction or a control pulse acting oppositely to the counting direction and that for the change-over a dead time, specific to the circuit, must elapse between two successive operations of the two counting inputs 7,8. When a counter 6 of this kind is used for the present purposes this circumstance would lead to complications, particularly when an impulse is transmitted by each of two pulse transmitter elements 9.1 and 9.2 simultaneously or in very rapid succession. This may for example occur in the case of very slight slip or of accidental coincidence, due to the spatial arrangement of the pulse transmitter 9.1, 9.2, of the points on the periphery of the clutch parts which determine the timing of the impulse transmissions.
In order to eliminate such complications despite the use of a simple counter 6 and in accordance with the invention, a two-channel decoupling circuit 10 is connected between the pulse transmitter and the counting inputs 7, 8 of the counter 6. This circuit ensures that even if the pulse transmissions overlap or closely follow one another from the pulse transmitter elements 9.1, 9.2, the counter 6 will be correctly operated without these signal pulses being lost for monitoring the slip. In the interest of undisturbed signal processing it is expedient for pulse formers 11 to be interposed between each of the two channels 10.1, 10.2 of the decoupling circuit 10 and the pulse generator elements 9.1 and 9.2 respectively in order to make available defined pulses on the operation of the pulse generator elements 9.1 and 9.2 respectively.
The output signal of the operated pulse former 11 is taken over in an erasable store 12 in the appertaining channel 10.1 or 10.2, this store being shown in the embodiment illustrated in the drawing as a bistable trigger stage. In each channel 10.1, 10.2, an interlock stage 13.1 and 13.2 respectively, is connected downstream of the store 12, this stage having the effect that when one of the two channels 10.1 or 10.2 is operated by the setting of the corresponding store 12, the corresponding interlock stage 13.2 or 13.1 in the other channel (10.2 or 10.1) is switched over to blocking. In order to explain this function, in the illustrated embodiment each interlock stage 13.1, 13.2 is provided as an AND gate having one direct input and one inverting input, the inverting input being connected in each case to the output of the interlock stage 13.2 or 13.1 of the other channel 10.2 to 10.1. A delay element 14 is connected downstream of each interlock stage 13.1, 13.2, and is shown in the drawing as a monostable trigger stage; this delay element 14 allows an input pulse to appear at its output, which in the example of the circuit illustrated is identical with the corresponding channel output, only after an adjusted time lag. One channel 10.1 is connected to the forward counting input 7, and the other channel 10.2 is connected to the backward counting input 8 of the counter.
When the pulse generator elements 9.1 and/or 9.2 transmit a pulse (simultaneously or in succession), the store 12 connected downstream in the associated channel 10.1 or 10.2 is set by way of the appertaining pulse shaper 11. The delay element 14 is, however, operated only in that channel 10.1 or 10.2 whose store 12 was set before the store 12 of the other channel 10.2 or 10.1, because when an output signal is present at one of the stores 12, the other channel 10.2 or 10.1 is immediately blocked by means of the interlock stage 13.1 or 13.2. On operation of the appertaining counting input 7 or 8, the appertaining store 12 is reset as the result of the feedback from the output of the channel 10.1 or 10.2. The interlocking in the other channel 10.2 or 10.1 is thus cancelled and the output signal of the other store 12 is switched through to the associated delay element 14 which on expiry of its time lag operates the other counting input 8 or 7 of the counter 6.
Consequently, the two-channel decoupling circuit 10 ensures that both the counting inputs 7 and 8 of the counter 6 cannot be operated simultaneously, even in the event of simultaneous or overlapping pulse transmission by the pulse generator elements 9.1 and 9.2. The delay elements 14 ensure that after the resetting of a store 12 and consequently the release of the interlock stage 13.1 or 13.2 in the neighboring channel 10.1 or 10.2 -- which now leads to the operation of the delay element 14 when the store 12 in question is set -- the other counting input 7 or 8 of the counter 6 will be operated only at the end of the time lag. The time lags of the delay elements 14 are thus to be adjusted at least to the minimum retardation time, specific to the counter, between the change-over from one counter input 7 or 8 to the other. It is true that retarded operation of the counter 6 is thus generally effected, but because of the short time lags used in practice it has been found that this does not lead to complications in the monitoring of slip for the protection of the overload clutch 5. In order to prevent reciprocal blocking in the event of exactly simultaneous operation of the two channels 10.1, 10.2, it is expedient for the delay elements 14 to be adjusted to slightly different time periods.
As already explained, an overload clutch 5 of the kind dealt with here has a certain minimum slip even during normal operation. This means that -- after a certain period of operation -- between two operations of the backward counting input initiated by the driven clutch element there will be not one but two operations of the forward counting input 7 of the counter 6. In other words, over a long period of operation the slight operating slip has the effect that not every forward counting of the driving clutch part will be compensated by a successive backward counting initiated by the driven clutch part. This is to say that in the course of the operating period the counter 6 will not always only count to-and-fro between the counting results "zero" and "one," but will also count beyond "one." The speed of this slow forward counting can be determined through the operating slip specific to the clutch. In this way a period of time can be predetermined within which, if only the operating slip exists, a determined counting result cannot be exceeded. In order to predetermine this period of time, a time base stage 15 is connected to the counter 6 and on expiry of this period of time resets the counter 6 to the initial counting position "zero."
If, however, before expiry of this period of time defined by the time base stage 15 the critical counting result just defined should be reached, this is proof that the slip of the overload clutch 5 has increased in relation to the operating slip, because in consequence of a correspondingly increased rotational speed of the driving part of the clutch in relation to the driven part of the clutch the backward-counting pulse are increasingly delayed in relation to the forward-counting pulses.
This critical situation is dealt with by connecting downstream of the counter 6 a decoding stage 16 which is adjusted to a predetermined counting result which can just not be achieved within the period of time predetermined by the time base stage 15 if only operating slip occurs in the overload clutch 5. This decoding stage may, for example, be an adjustable or wired-in counting interrogation system, with dual or decimal decoding depending on the type of counter 6.
When the decoding stage 16 responds because the slip in the overload clutch 5 has increased in relation to the operating slip, a signal generator 17 connected to its output is operated and operates a warning signal device 18, which acts, for example, optically or acoustically. In particular, however, it is expedient for a clutch disconnection device 19 also to be connected to the output of the signal generator 17, thus ensuring that the overload clutch 5 is disengaged immediately on the exceeding of the permissible operating slip, that is to say is protected against destruction resulting from the generation of heat.
With the circuit arrangement described so far, reliable protection of the overload clutch 5 when the slip increases beyond the operating slip is ensured. In order, however, also to protect the overload clutch 5 when for any reason, for example through accidental failure to connect the pulse generator elements 9.1, 9.2, the two-channel decoupling circuit and consequently also the counter 6 are not operated at all, a timing element 20 is connected in parallel to the input of each channel 10.1, 10.2, the outputs of this timing element being connected to the signal generator 17 by way of an OR gate, in parallel to the output of the decoding stage 16. When the circuit arrangement is put into operation, each of these timing elements 20 is set, and if no pulse arrives from the appertaining pulse generator elements 9.1 or 9.2 before expiry of the adjusted period of time the respective timing element 20 will drop back and transmit an output signal to the signal generator 17, in order to disconnect the two parts of the overload clutch 5 from one another as a precaution, since otherwise the overload clutch 5 would not be monitored by the circuit arrangement described. If no pulses arrive from the pulse generator elements 9.1 or 9.2, the appertaining timing element 20 thus runs down and by means of the signal generator 17 disengages the overload clutch 5. The closing of a contactor 22 resets the signal generator 17, but does so only when both the timing elements 20 have run down. With the reset signal of a reset circuit 21 the signals produced by the timing elements 20 are blocked in order to enable the signal generator to be reset. When the driven machine 2 starts up again, the output signals of the timing elements 20 disappear after the first respective pulse from the pulse generator elements 9.1 and 9.2, and when the contactor 22 is opened again the overload clutch 5 is once more monitored.
In order also to be able to start the machine 2 extremely slowly despite the safety system consisting of the timing elements 20, it may be expedient not to change the characteristic times of the timing elements 20, but to provide the signal generator 17 with bistable switching behavior, the reset circuit 21 being connected to its reset input. If the signal transmission to this reset input is predominant in relation to a signal transmission to the previously mentioned setting input (operated by the timing elements 20 or by the decoding stage 16), the action of the signal generator 17 can be blocked by means of the contactor 22 during intentionally slow starting.
After disconnection of the overload clutch 5 through the action of the signal generator 17 when excessive slip occurs, the driven part of the clutch, which is connected to the blocked extruder machine 2, will be very abruptly brought to rest. The driving shaft end 3 connected to the geared motor 1 will on the other hand continue to rotate without load, unless special braking means are provided. In order to prevent reengagement of the overload clutch 5 at a moment when the driving part of the clutch together with its shaft end 3 is still rotating at high speed, it may be expedient for a rotational speed monitor to be connected downstream of, at least, the pulse generator element 9.1 associated therewith, this monitor resetting the signal generator 17 -- still with bistable switching behavior -- only whtn the instantaneous rotational speeds of the two shaft ends 3 and 4 coincide to within permitted limits. Acording to a convenient further development of the invention, the function of a rotational speed monitor of this kind is likewise served by the timing elements 20, for which reason their outputs in the reset circuit 21 are combined through logic components with the operation of the contactor 22.
Since the critical rotational speed of the driving clutch part must in fact in practice be very low for reengagement of the overload clutch 5, it is sufficient for the timing elements 20 to be constructed, for example, as retriggerable monostable trigger stages, which produce a signal when the pulse transmission from the pulse generator elements 9.1 or 9.2 connected upstream in the circuit is not repeated at least once within the switch-back time of these trigger stages. If therefore one of these timing elements 20 in the form of monostable trigger stages switches back, this means adequate lowering of the rotational speed of the appertaining part of the clutch, and only then will the signal generator 7 be cleared by means of the contactor 22 and the reset circuit 21 and the operation of the coupling disengagement device 19 be terminated. | A circuit arrangement for protecting an overload coupling includes respective pulse generating elements which produce respective pulse trains, the difference between individual repetition rates of which is a measure of slip. A pulse comparator, in the form of a resettable forward-backward counter receives outputs from the two pulse generating elements and is provided with a reset input. A decoding stage is connected to receive the counting result output from the counter. A warning signal generator receives the output of the decoding stage. A disconnecting device is operatively arranged to disengage the coupling upon production of a signal from the decoding stage indicating a given slip. | 5 |
BACKGROUND OF THE INVENTION
Numerous kinds of puzzles are in existence for the purpose of providing amusement with varying degrees of challenge. Some of the currently popular puzzles employ relatively movable parts which are so colored as to require the user to manipulate the parts in such manner as to locate all correspondingly colored parts adjacent one another. Others utilize rotatable or slideable members bearing numbers or colors or parts of designs which, when the members are arranged in a predetermined order, will display the numbers or colors or design parts in a selected pattern. Some of these latter puzzles are flat, whereas others are cylindrical. Some of the cylindrical puzzles have designs which are visible wholly circumferentially of the cylinder, whereas others have designs which are visible only through slits or slots cut in a covering cylinder.
In the production of a puzzle employing relatively movable, cylindrical members each bearing segments of a design, and wherein the design is intended to be visible about the whole circumference of the cylinder, it is desirable that the solution to the puzzle depend upon proper alignment of the design segments, rather than upon the alignment of mechanical features having nothing at all to do with the design. Accordingly, the principal object of the present invention is to provide a method of producing a puzzle composed of a plurality of rings each of which bears a selected portion or segment of a predetermined design, the rings being independently rotatable to align or register the individual design segments and thus display the whole design. The rings are so constructed that they themselves give no clue to the positions the rings must occupy relative to one another to display the design.
SUMMARY OF THE INVENTION
A puzzle according to the invention is formed from a two-dimensional sheet of material, such as paper, bearing any one of a number of different designs. The sheet is cut horizontally into a plurality of parallel, horizontal strips, following which most or all of the strips are cut transversely into two pieces. The pieces of each strip then are rearranged end-to-end to form second strips.
The rearranged second strips then are joined to one another at their confronting edges and thereafter formed into endless rings and assembled on a spindle for independent rotation. Relative rotation of the rings will enable the segments or portions of the designs on each ring to be aligned or registered in such manner as to reproduce and display the original design.
DESCRIPTION OF THE DRAWINGS
The method according to the invention is illustrated in the accompanying drawings, wherein:
FIG. 1 is a plan view of a sheet of material bearing a selected design;
FIG. 2 is a view similar to FIG. 1, but illustrating the sheet cut along horizontal and transverse lines to form parallel strips composed of two pieces each;
FIG. 3 is a view similar to FIG. 2, but illustrating the individual pieces of each original strip rearranged end-to-end to form modified or second strips;
FIG. 4 is an isometric view illustrating the modified strips formed into endless rings and mounted for rotation about a spindle; and
FIG. 5 is a view similar to FIG. 4, but illustrating the rings occupying positions such as to reproduce the original design.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A puzzle formed in accordance with the invention commences with the production of a two-dimensional design D on a sheet S of material such as paper, cardboard, plastic, and the like. The design D may be a representation of an object, a landscape, or a portrait, or a series of numbers, a plurality of colored squares, or any other suitable design. For purposes of simplicity in illustrating the method, design D is illustrated as a relatively small oval, but it will be understood that it is preferable for the design to cover the entire surface of the sheet S.
The sheet S is cut horizontally along spaced lines 1, 2, and 3 to form four separate strips 4, 5, 6, and 7. The strip 4 has opposite ends 8 and 9, the strip 5 has opposite ends 10 and 11, the strip 6 has opposite ends 12 and 13, and the strip 7 has opposite ends 14 and 15.
If each of the strips 4-7 were formed into rings by joining the opposite ends 8, 9; 10, 11; 12, 13; and 14, 15, then such joined ends would form a seam which, when aligned vertically, would reproduce the design D. Thus, it would be a simple matter to rotate the rings in such manner as to align the seams and reproduce the design D and the puzzle would present no challenge. According to the invention, therefore, the strips 4-7 are treated in such manner as to frustrate reproduction of the design D by reference to mechanical characteristics such as the aforementioned seams.
According to the invention the strip 4 is cut transversely along the line 16 to form two pieces 17 and 18. The piece 17 thus has ends 8 and 19 and the piece 18 has ends 9 and 20. The strip 5 is similarly cut along a vertical line 21 to form two pieces 22 and 23, the piece 22 having ends 10 and 24 and the piece 23 having ends 11 and 25. The strip 6 similarly is cut along the line 26 to form two pieces 27 and 28, with the piece 27 having ends 12 and 29 and the piece 28 having ends 13 and 26. In like manner, the strip 7 may be cut along the line 31 to form two pieces 32 and 33. The piece 32 has ends 14 and 34 and the piece 33 has ends 15 and 35. It should be understood that not all of the strips 4-7 need be cut into two pieces, but for purposes of illustration each is shown as being cut.
Following cutting of the strips to form two pieces from each, the pieces of each strip are rearranged end-to-end to form modified or second strips. Thus, the strip 4 is rearranged by having the end 9 of the piece 18 abut the end 8 of the piece 17 and form a modified second strip 36, as is shown in FIG. 3. Similarly, the strips 5, 6, and 7 are rearranged to form modified strips 37, 38, and 39, respectively. The design D thus will be restructered with each of the strips containing some segment of the design.
Following the arrangement of the original strips 4-7 to form the modified or second strips 36-39, the abutting ends of the respective strips may be adhered to one another and each strip formed into an endless ring. Thus, the ends 19 and 20 of the strip 36 may be joined to form a first ring 40 (FIG. 4), the ends 24 and 25 of the strip 37 may be joined to form a ring 41, the ends 29 and 30 of the strip 38 may be joined to form a ring 42, and the ends 34 and 35 of the strip 39 may be joined to form a ring 43. While maintaining the vertical order of the rings 40-43, they then may be placed in encircling relation about a spindle 44 provided at its ends with enlarged caps 45 and 46 which maintain the rings assembled with the spindle 44 and enable relative rotation of the rings about the axis of the spindle.
If the sheet material from which the strips are cut is relatively thin, the strips may be adhered to thicker or stiffer material either prior to or following being formed into rings.
The joining of the ends 19 and 20 of the strip 36 forms a seam 47 (FIG. 4), the joining of the ends 24 and 25 of the strip 37 forms a seam 48, the joining of the ends 29 and 30 of the strip 38 forms a seam 49, and the joining of the ends 34 and 35 of the strip 39 forms a seam 50. Each of these seams is readily visible and may be aligned vertically as is shown in FIG. 4. The vertical alignment of such seams, however, will not result in the reestablishment of the design D. To reestablish the design D following mounting of the rings 40-43 on the spindle 44, each ring must be adjusted relatively to the others until such time as the design segment carried by each ring mates with the design segment of the adjacent ring or rings, as is shown in FIG. 5. In these adjusted positions of the parts the seams 47-50 will not be aligned. Thus, the design can be reproduced only by proper orientation of the rings with reference to the design segments appearing thereon.
Although the puzzle can be produced by the physical joining of each of the pieces of the respective original strips to one another, followed by the forming of the thus modified strips into rings, it is preferred to assemble the rings and pieces in the manner shown in FIG. 3, following which any desired number of reproductions can be made photographically or otherwise. Thereafter, each of the sheets on which the reproduction appears may be cut horizontally along lines corresponding to the cuts 1-3 to form tertiary strips which then are formed into rings and assembled on the spindle 44 in the same manner as has been described earlier.
This disclosure is representative of a presently preferred method of producing a puzzle, but is intended to illustrative of the invention rather than definitive thereof. The invention is defined in the claims. | A method of forming a puzzle comprises cutting a sheet having a design thereon into a plurality of parallel strips, cutting some or all of the strips transversely to form multiple pieces, rearranging the pieces of each cut strip end-for-end to form secondary strips, forming each of the strips into an endless ring, and assembling the rings on a spindle for independent rotation about a common axis. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates generally to the field of water treatment; more particularly, to settling tanks in water treatment systems wherein grit and dense solids are allowed to settle from the influent, and buoyant solids (fats, oil, grease, non-dense solids) are prevented from entering into an effluent decanter; and most particularly, to a vertically driven screen box assembly (SBX) comprising a screen for separating liquids from solids.
BACKGROUND OF THE INVENTION
[0002] In developed and developing countries, primary treatment and disinfection of waste water discharges from collection systems and waste water treatment facilities is the first step to improving water quality. As the countries continue to advance, secondary and tertiary waste water treatment processes are added to provide additional treatment of the primary effluent.
[0003] Primary treatment removes large solids via screening and gravitational settling to remove light and dense solids, allowing neutrally buoyant matter to pass into the secondary treatment process or receiving body of water. Primary treatment utilizing gravitational settling or clarification is recognized as removing 20-33% of the organic load as measured in Biochemical Oxygen Demand (BOD). Secondary treatment removes another 50+% of the organic load by converting the BOD to biomass (bacteria) and CO 2 .
[0004] Secondary treatment provides an environment of adequate temperature, volume, mixing, and oxygen or the absence of oxygen in anaerobic processes to sustain the bacterial population necessary to consume the BOD and nutrients remaining in the waste water after primary treatment. New organic matter enters the treatment facility continuously so a portion of the existing bacterial population is removed from the process to promote the growth of new bacteria. The effectiveness of primary treatment directly affects secondary process or the receiving body of water if discharged from the collection system.
[0005] Primary clarifiers or settling basins are recognized as being the most economical means to reduce BOD as there is little energy required and no biomass to maintain. Primary treatment has no biomass therefore no aeration energy; no process controls to monitor the biomass to determine the health of the biomass by the types and quantity of the bacteria; no need to separate and remove or waste the bacteria by moving to a side-stream digester; no need to aerate the digester; and no need to dewater and dispose of the surplus bacteria, also called secondary sludge. The lack of complexity of primary treatment is well suited for developing nations and begins an effective recovery of their surface waters and aquifers resulting in reduced health issues.
[0006] Prior art primary clarifiers may be circular or rectangular tanks and are volumetrically and geometrically sized to provide a horizontal fluid velocity lower than the solids settling velocity. The horizontal travel time and distance of the liquid from the inlet to the effluent weir must be greater than the settling time and distance of the suspended solids so that solids settle to the bottom of the tank prior to reaching the elevated effluent weir. These settled solids contain a majority of the BOD in raw sewage. This is an important first stage because the more solids that exit the primary clarifier (or if there is no primary clarifier), the higher the BOD entering the secondary treatment process or the effluent-receiving body of water. The higher the BOD entering the secondary treatment process, the larger the required secondary process equipment and tanks, the more biomass required, generated, and disposed of, the more processing energy that must be expended. The higher the BOD of the effluent stream entering the receiving body of water the greater the eutrophication of the water body and the more detrimental to the health, due to poor disinfection.
[0007] An example based on standard design parameters to achieve 33% BOD reduction is shown as follows:
[0008] Minimum depth=10′; Surface Overflow Rate=1,000 Gallons per day (GPD)/square foot (design) and 1,500 GPD/SF (Peak); Weir Loading @ Peak Hourly=20,000 GPD/linear foot;
[0009] Use Design Flow=1,000,000 GPD (1.55 CFS); Peak Hourly=2,500,000 GPD (3.87 CFS);
[0010] Design=1,000,000 GPD/1,000 GPD/SF=1,000 SF; Peak=2,500,000/1,500=1,667 SF
[0011] Typical design seeks a length about 3 times the width so, 1,667 SF=24′ wide×70′ long×10′ deep; Forward velocity=3.87 CFS/(10′×24′)=0.016 Ft. per Second (FPS).
[0012] An EPA study provided a summary of settling data from multiple wastewater plants. The table below is an average of pertinent findings to support the design parameters as they relate to BOD reduction:
[0000]
Organic
Average
Suspended
% Primary
(BOD)
Settling
% >50
% BOD
Solids
Sewage
Content
Velocity
microns
Reduction
Settleable
45
50%
0.106 FPS
64%
22.5%
(>100 microns)
Supracolloidal
35
30%
68%
0%
(1-100 microns)
Colloidal
20
20%
0%
0%
(0.2-1.0 microns)
[0013] The values in the above table are averages taken from several WWTP that include storm water, combined sewer systems, and sanitary sewage. The settleable solids have a settling velocity range from 0.016 to 0.115 FPS with an average of 0.106 FPS as stated in the table.
[0014] The design example above results in a forward velocity of 0.016 FPS which is less than the average settling velocity of 0.106 FPS. The tank is 10′ deep so the solids will settle in 94 seconds. The forward distance travelled in 94 seconds is 1.5 Feet so the solids will settle before the liquid reaches the effluent weir. The EPA study expressed considerable difficult in establishing a consistent average for the supracolloidal and colloidal solids as they vary from site to site and range from 0.0007 to 0.002 FPS. The forward velocity is 0.016 FPS and the tank is 70 Ft long therefore the travel time=4,375 seconds therefore the depth of settling is 3′ to 8.75′.
[0015] The effluent weir is 2,500,000 GPD/20,000 GPD/Ft.=a minimum of 125′, the tank is 24′ wide therefore use 3-double sided weirs providing 144′ of weir length so the flow is 2,500,000 GPD/144=17,361 GPD/Ft or 0.027 CFS/Ft. at the weir. The velocity of the liquid at 3′ from the weir is 0.0057 FPS and at 8.75′ the liquid velocity is 0.002 FPS. Some portion of the supracolloidal solids will be removed as per this mathematical exercise on clarifier velocities, but very little of the colloidal solids.
[0016] It would be reasonable to expect the primary clarifier in this design example to reduce the BOD to the receiving stream or secondary treatment process by 33%.
[0017] Developed and developing nations, as well as the environment, would significantly benefit from removing more than 20-33% of the organic matter from the waste water in the primary treatment because;
Less CO 2 would be released to the atmosphere. Less energy consumed to convert the organic matter (BOD) to biomass (secondary sludge) Less secondary sludge to pump, store, aerate, dewater, and send to landfill Fewer trucks hauling secondary sludge to landfill or composting facilities Landfills would have a longer operational life and release less methane to the atmosphere Smaller secondary treatment system would be possible resulting in significant capital costs savings for the developed and developing countries allowing more to be done sooner Lower operational and maintenance costs for the secondary treatment systems Higher quality primary effluent would accelerate improvements to the receiving waters and reduce environmental health and safety issues The higher concentration of organics in the primary sludge significantly increases the energy generation potential in anaerobic digesters. Anaerobic Digesters capture and utilize the methane gas created from the high volatile primary sludge to produce energy versus releasing most of the methane to atmosphere due to poor capture systems in landfills. Waste water treatment plants become a renewable resource recovery facility creating more energy than they consume as the organic load to the secondary treatment process is reduced and the organic fuel for the anaerobic digesters is increased. Anaerobic Digestion creates less bacteria and results in a Class A sludge that can be used for composting.
[0029] The organic removal rate of primary clarifiers can be improved from 33% to approximately 50% by the addition of coagulating chemicals. This improvement is called Chemically Enhanced Primary Treatment (CEPT) and CEPTs have demonstrated all of the above described benefits. There were no physical or operational modifications to the primary clarifier tank, influent flow baffle, sludge scrapper mechanisms, scum trough or effluent trough. The coagulant forms a floc or gel net that is larger and more dense than the individual suspended solids. As this floc settles it gathers some supracolloidal and colloidal particles thus reducing the BOD and suspended solids flowing to the secondary treatment process.
[0030] The Ballasted Floc Reactor (BFR) followed the CEPT in an attempt to remove more BOD and reduce capital costs. The BFR technology removes approximately 50% of the BOD, the same as CEPT, but with a smaller clarifier because the solid settling rate is much higher.
[0031] Developing nations would likely not be able to see the benefits of enhanced BOD reduction with the CEPT or BFR products because the chemicals and skilled operators may not be available.
[0032] In summary, conventional primary clarifiers, BFRs and CEPTs do not have screened effluent weirs to retain the supracolloidal and colloidal organic particles. Simple placement of a screen at existing effluent weirs will not work because a) such screens would foul in a short time frame due to the high flow velocity at the weir weir design liquid flow velocities; b) such screens would be stationary so there is no backwashing; and c) such screen would foul due to organic growth on the screen since the screen is in the liquid all of the time. The forward velocity from the inlet to the effluent weir is constant so there is an inertia imparted into the solids keeping them moving towards the effluent weir; there is no velocity control within the tank as the tank is always full so if 10 gallons of liquid enters the tank, 10-gallons of liquid must exit the tank at the same rate as it was added; and the sludge removal equipment in the tank is continually moving and disturbing the settled sludge creating eddies that keep neutrally buoyant constituents and colloidals in suspension moving towards the effluent weir at a high effluent weir entrance velocity.
[0033] A screened decanter comprising an effluent weir is disclosed in U.S. Pat. Nos. 7,972,505 and 8,398,864, the relevant disclosures of which are incorporated herein by reference. The movement of a screened decanter is an arc rotating about a pivot. The vertical movement of the screened decanter about a pivot comprises both horizontal and vertical movement in the direction of motion. Depending upon the depth of the tank, the length of the pivot arm requires that the decanter assembly occupy a relatively large footprint in the tank.
[0034] What is needed in the art is a screen assembly in the form of a rectangular box or cylinder that is controllably driven in the vertical direction to optimize the exposure of the screen to the wastewater to varying wastewater levels and that can be lifted from the wastewater for backflushing and sterilization in a dedicated overhead apparatus. Because the motion of the screen assembly is only vertical, the required footprint can be relatively small.
[0035] What is further needed is an assembly comprising a ganged plurality of such screen box assemblies for wastewater systems having high flows, limited surface area, and/or shallow active tank volumes.
[0036] It is a principal object of the invention to provide a high and constant effluent flow rate from a wastewater treatment facility over a wide range of influent flow rates.
SUMMARY OF THE INVENTION
[0037] Briefly described, the present invention provides a screen assembly in the form of a rectangular box or cylinder that is controllably driven in the vertical direction to optimize the exposure of the screen to the wastewater to varying wastewater levels in a wastewater clarifier and that can be lifted from the wastewater for backflushing and sterilization in a dedicated overhead apparatus.
[0038] A screen box (“SBX”) assembly in accordance with the present invention comprises an ultrafine screen; a screen frame of flat plate and hollow tubing that incorporates air scouring at the lowest elevation of the screen, the frame being sealed to prevent liquids and solids from bypassing the screen so all must pass through the screen; a flexible discharge hose that may have swivel joints or may extend and compress in an accordion fashion to minimize forces on the screened decanter; guiderails to define the vertical and horizontal movement of the invention; a lifting device to raise and lower the invention in the liquid at controlled descent speed and multiple rise rates; an effluent flow manifold with openings to allow liquid to flow to the screen from below the screen; a deflector plate with drain ports; an encoder to position the screen box in the tank to measure headloss and to insure the appropriate amount of screen is in contact with the wastewater; a protective maintenance hood to backwash, disinfect, and thaw the screen; controls, sensors, actuated valves, modulating valve, flow meter, and in some cases a filtrate pump if required by the existing hydraulic gradient.
[0039] Multiple units of the invention may be necessary to meet the needs of each application; similarly, multiple units of the invention may be used in the same tank to provide a redundant system as desired.
[0040] A SBX assembly defines a physical barrier providing a very low horizontal velocity to the wastewater exiting the clarifier so as to retain most of the supracolloidal and colloidal solids. The physical barrier has openings small enough to keep a majority of the supracolloidal solids within the primary clarifier. The deflector plate prevents the disturbance of the settled solids below the deflector plate and increases the travel time of liquid to discharge at the screen.
[0041] The fundamental difference between a prior art weir structure and a novel vertical screen structure in accordance with the present invention is that a weir structure permits only a relatively shallow layer of fluid from the top of the fluid mass in the tank to pass over the weir to exit the tank, thus creating comparatively high horizontal flow velocities which work against providing sufficient time for solids to settle below the level of the weir. A vertical screen structure, to the contrary, permits horizontal flow from the tank into the screen structure over a comparatively large surface area of screen and depth of flow, thus requiring only very low horizontal flow velocities to separate relatively large volumes of fluid from the tank fluids.
[0042] The vertical position of the SBX is controllably adjustable to provide a change in liquid elevation and a rest period with no forward velocities that allow the supracolloidal and colloidal solids in suspension to mix with the coagulant and settle, as there is no velocity towards the discharge. Such controls include a modulating screened effluent discharge valve, flow meter, and electronic control system that adjusts the screen surface area in contact with the liquid to maintain a screen loading rate (GPM/Sq. Ft. of Screen) based on discharge velocity, resulting in reduced screen fouling. Pressure transducers, encoders, and controls to measure headloss through the screen and to control the movement of the screened decanter are included in the system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The foregoing and other objects, features, and advantages of the invention, as well as presently preferred embodiments thereof, will become more apparent from a reading of the following description in connection with the accompanying drawings in which:
[0044] FIG. 1 is an elevational cross-sectional view of an SBX assembly in accordance with the present invention, showing the SBX screens being scoured by introduced air bubbles;
[0045] FIG. 2 is an elevational cross-sectional view like that shown in FIG. 1 , showing the SBX screens being ⅔ clogged;
[0046] FIG. 3 is an elevational cross-sectional view like that shown in FIG. 2 , showing the SBX screens being further immersed to permit continued operation of the unit with fresh screen surface;
[0047] FIG. 4 is an elevational cross-sectional view like that shown in FIG. 1 , showing the SBX being supported on a lifting column having slotted exit ports;
[0048] FIG. 5 is an elevational cross-sectional view like that shown in FIG. 4 , showing the exit ports being screened;
[0049] FIGS. 6 through 10 are elevational views of alternate configurations of exit ports in a lifting column;
[0050] FIG. 11 is an isometric view from above of an SBX and central lifting column, showing a lifting cable attachment;
[0051] FIG. 12 is an enlarged view of the lifting cable attachment shown in FIG. 11 ;
[0052] FIG. 13 is an elevational view of an SBX disposed for cleaning and disinfection in first embodiment of a hood in accordance with the present invention;
[0053] FIG. 14 is an elevational view of an SBX disposed for cleaning and disinfection in second embodiment of a hood in accordance with the present invention;
[0054] FIG. 15 is an elevational cross-sectional view of a complete wastewater treatment system, showing an SBX in raised position inside a cleaning hood;
[0055] FIG. 16 is an elevational view of a water treatment system, showing a hydraulic or pneumatic power pack for lifting the SBX;
[0056] FIG. 17 is an elevational cross-sectional view like that shown in FIG. 15 , showing an SBX in lowered position, freshly cleaned and entering into service;
[0057] FIG. 18 is an elevational cross-sectional view like that shown in FIG. 17 , showing an SBX having been controllably lowered in accordance with the present invention to follow a drop in tank level to maintain a desired immersion level of the SBX;
[0058] FIG. 19 is an elevational cross-sectional view like that shown in FIG. 18 , showing an SBX having been controllably lowered still farther to follow a further drop in tank influent level to maintain a desired immersion level of the SBX;
[0059] FIG. 20 is an elevational cross-sectional view like that shown in FIG. 19 , showing an SBX having been controllably raised from immersion to permit backwash of the screens in the SBX;
[0060] FIG. 21 is an elevational cross-sectional view of a dual-tank wastewater treatment system, showing the SBX in one tank being backwashed while the SBX in the other tank continues in normal service;
[0061] FIG. 22 is an isometric view from above, showing an SBX single-tank wastewater treatment system similar to that shown in FIG. 15 ;
[0062] FIG. 23 is an isometric view from above, showing multiple SBXs in a single tank wastewater treatment system;
[0063] FIG. 24 is an isometric view from above, showing a single SBX in a single-tank wastewater treatment system having a circular tank and circular SBX;
[0064] FIG. 25 is an isometric view from above of a larger circular wastewater treatment tank having a plurality of ganged cylindrical SBX units;
[0065] FIGS. 26 , 26 a are elevational and plan views of a prior art wastewater treatment system, showing the footprint required by a prior art pivoting decanter;
[0066] FIG. 27 , 27 a are elevational and plan views of a prior art wastewater treatment system, showing the footprint required by a retrofitted vertical lift SBX decanter system in accordance with the present invention;
[0067] FIG. 28 is an isometric view showing multiple racks mounted to a single discharge manifold with retractable air hose reels above in a single tank;
[0068] FIG. 29 is a plan view of multiple screen racks with square ends;
[0069] FIG. 30 is a plan view of multiple screen racks with rounded ends to create a volute shape to improve horizontal flow;
[0070] FIG. 31 is a plan view of multiple screen racks with triangular ends to improve horizontal flow patterns;
[0071] FIG. 32 is an isometric view of the spray header typically located inside a spray hood;
[0072] FIG. 33 is an isometric view of a spray bar having unique shaped orifices to send a horizontal fan of high pressure/low volume water to both inside faces of the screen box;
[0073] FIG. 34 is an isometric view of the backwash spray manifold and spray bars in the spray hood above a SBX having multiple screen racks;
[0074] FIG. 35 is an isometric view showing the upward movement of the SBX into the spray hood. The backwash water is activated when the top of the screen reaches the spray bar elevation and continues to backwash the SBX as it slowly rises in the spray hood and then shuts off when the bottom of the screen reaches the spray bar elevation;
[0075] FIG. 36 is an isometric of the multiple rack SBX inside the spray hood;
[0076] FIG. 37 is a cross-section view showing the spray bar and backwash manifold positioned inside the screen racks of the SBX;
[0077] FIG. 38 is a plan view of an LPSBX manifold; and
[0078] FIG. 39 is an isometric view of the LSBX manifold shown in FIG. 38 , shown in inverted position.
DETAILED DESCRIPTION OF THE INVENTION
[0079] Referring to FIGS. 1-39 , there is shown an SBX system 10 in accordance with the present invention, comprising the following elements:
[0080] Screen Box (SBX)
[0081] The top 14 of the SBX 12 ( FIG. 1 ) is normally open to allow occasional screen washing via hose or automated spray system (spray ball for the symmetrical shapes or spray bar for the long rectangular boxes) and to access instruments located inside of the screen box.
[0082] Some applications (not shown) may require a closed and sealed top when the screen box operates completely submerged except for air vents. These air vents also serve to store screened liquid 11 to provide additional backwash volume.
[0083] The bottom 16 of screen box 12 is a solid plate with open areas to allow screened liquid 11 to exit the screen box and thus the tank. The solid plate 16 and closed effluent valve 18 ( FIGS. 15-23 ) requires all screened liquid inside of screen box 12 to exit via the screened sidewalls to improve screen backwashing at the end of each decant cycle.
[0084] The sides 20 of screen box 12 consist of screen 22 and screen framing members 24 that may be vertical (perpendicular to the liquid surface) or sloped so that the top of the screen box is wider than the bottom creating a frustum shape. This allows for more screen surface to be in contact with the influent liquid 13 , and liquid 13 enters from all sides thus decreasing the approach velocity 15 to the screen.
[0085] Some screen boxes may only have screened surfaces below the surface of the liquid with a solid vertical plate above the screen. The solid portion may be partially submerged to increase the volume of screened liquid inside of the screen box used for backwashing of the screen. This solid portion also will not foul due to fats, oils, and grease on the surface of the liquid.
[0086] Screens that are elongated and spaced closely to other screen boxes or racks may have a rounded or triangular end pieces to direct horizontal flow to between the racks with less turbulence in a more laminar flow.
[0087] Preferably, each screen rack is formed of fiberglass to avoid the corrosive decay to which metal racks and gaskets may be subject. Each screen is laminated to a flat sheet of FRP with an air scour header 24 ′ laminated across the base of the screen. Preferably, header 24 ′ contains low pressure air on the inside with small openings (not visible in FIG. 1 ) in the top of header 24 ′ to provide air bubbles 26 to air scour to the screen surface. It is critical that screen box 12 be sealed along all edges to prevent the liquid 13 in the tank from entering screen box 12 by any means other than passing through screen elements 22 . Gasketing may be provided as necessary, although non-gasketed arrangements are preferable.
[0088] Air 26 is released at the base of the screen surface through the tubular screen frame as described above. The vertical flow of air scours the external surface of the screen. Solids that may be pressed against the exterior surface of the screen by liquid moving through the screen are disturbed and carried upward. The vertical flow of air and solids also aligns elongated fibers vertically, or perpendicular to the openings in the screens, to reduce passage of solids through the screens.
[0089] Preferably, an oxidant solution (e.g., aqueous sodium hypochlorite or potassium permanganate) is injected into the compressed air line.
[0090] The ultrafine screen currently preferred is a SS wire woven as a fabric. Screens of different materials and opening sizes may be used in certain applications.
[0091] Multiple SBX modules 98 with individual synchronized lifting devices ( FIG. 23 ) are likely for large flow installations and as redundant units. The features of each module include the previously described screen, screen attachment, air scour, hood, solid plate bottom, and may or may not include a closed top with air vents and other features described below.
[0092] Referring to FIGS. 24 and 25 , a second embodiment 12 ′ of an SBX in accordance with the present invention may be cylindrical (circular) or conical (not shown). To provide added capacity, a plurality of SBXs may be ganged in parallel, as shown in FIG. 25 . A cylindrical SBX is especially useful in an installation having a cylindrical tank. The structure and operation of a cylindrical SBX is similar to that of a polyhedral SBX 12 .
[0093] Comparison of Prior Art Clarifier Weir with a Screen Box Decanter
[0094] Preferably, the present screen box system incorporates coagulation and an ultrafine screen.
[0095] For a conventional primary clarifier weir, the horizontal velocity of fluid at the weir may be calculated as follows:
[0000] 20,000 gallons per day/foot of weir=0.0309 cubic feet per second/foot of weir.
[0096] If the liquid depth over the weir is 3 inches, the horizontal fluid velocity at the weir=0.124 FPS.
[0097] To the contrary, an SBX in accordance with the present invention can provide a horizontal fluid velocity of <0.009 FPS. Combining the use of a coagulant, ultrafine screen, and effluent velocity approximately 13 times lower than the conventional primary clarifier can produce a BOD removal of 65% to 85+%.
[0098] In addition to the previously stated benefits related to organic (BOD) reduction, secondary wastewater treatment processes can see additional benefits from the invention in:
Improved oxygen transfer efficiency to further reduce energy consumption. Removal of fibers that cause fouling of hollow fiber and flat plate membranes so reduced air scour energy, increase the membrane life, and reduce operational issues requiring Clean-In-Place (CIP) activities.
[0101] Without chemical addition, an SBX system in accordance with the present invention can remove approximately 55% of the BOD. The ultrafine screen has openings smaller than the supracolloidal particles; the air scour causes an upward velocity greater than the forward velocity of the exiting liquid causing fibers to align vertically or perpendicular to the screen openings; the reduced velocities at the screen improve settling; the deflector plate increases the travel distance of the settled BOD laden solids under the screened decanter (as shown in FIG. 18 ) and stops the vertical velocities of the rising air bubbles from disturbing and carrying the settled BOD up towards the screen.
[0102] Screen box 12 replaces the effluent weir 100 used in all prior art clarifiers, (see, e.g., FIG. 26 ). The benefits of the screen box over the conventional effluent weir or launder are:
[0000]
Conventional
Effluent Weir
Or Launder
Screen Box
Benefit
Stationary
Moves
A vertically moving weir changes dynamics of
Effluent Weir
Vertically
clarification by allowing the liquid level in the tank to
change as a stationary effluent weir maintains a
minimum liquid level in the clarifier/tank equal to the
elevation of the weir. Water enters the clarifier and the
liquid near the weir immediately exits at the same rate
as water does not compress and the tank does not
expand to store this additional water. The invention
decants the liquid in the clarifier to a low level then
rises out of the tank.
Water enters the clarifier having a low level and fills to
a higher level. During this filling process there is no
means for the contained water to exit the clarifier as the
(SBX) is out of the tank. Therefore there is no
directional flow or inertia or energy instilled into
neutrally buoyant solids and there is no scouring or
suspension of settled solids near the bottom of the
clarifier that would occur if the water were continually
moving towards an effluent weir.
Weir that rotates
Weir that
Vertical movement has no horizontal dimension.
about a pivot
Moves
Movement about a pivot has both horizontal and
vertically
vertical dimensions. The horizontal motion must be
considered in the design of a new clarifier or the retrofit
of an existing clarifier. In all cases the horizontal space
is larger for a pivoting than a vertical moving weir.
A fixed weir that rotates about a pivot is limited to the
width of the tank and receives flow in one direction,
towards the weir. If a second weir is added to the same
pivoting decant arm in an attempt to reduce the liquid
velocity at the weir, the weir with the shortest radius
will always be lower in elevation than the weir traveling
along a longer radius. The weir and decanting arm uses
gravity flow so the potential range of motion is limited
to 9:00 to 12:00 or 12:00 to 3:00 (At 12:00 the decanter
is out of the water and at 3:00 there is no hydraulic
gradient so there is no flow at the ends of this range).
The liquid will travel to and over the weir with the
lowest elevation in the water at a disproportionate rate
creating uneven flow patterns through the screen
causing regionalized fouling issues.
A vertically moving screen (no pivot) can have more
than one weir or one continuous weir that remains at the
same elevation throughout the full vertical range of
motion. The weir is screened so an increased amount
of screen is receiving equal flow thus reducing the
velocity at the water/screen interface.
Physical Weir
No physical
The liquid must flow over a physical edge and free
weir
fall. The free fall of water creates a slight pulling
action and no frictional headloss. Both of these create
a high weir entrance velocity. As an example, a 3′ long
weir with 1′ depth of water over the weir has a
discharge flow rate of 35.4 GPM or 0.079 CFS/0.083
SF = 0.95 FPS @ weir.
There is no weir in the screen box with the liquid level
set by the effluent flow and selected screen loading rate
(GPM/Sq. Ft. of screen). Using a screen loading rate
of 4 GPM/SF and the same flow rate of 35.4 GPM the
required screen surface area is 35.4 GPM/4 GPM SF =
8.85 SF of screen, The screen box is positioned based
on screen configuration to a depth placing 8.85 SF of
screen in contact with the liquid. The velocity of the
liquid at the screen is 4 GPM/448.8 = 0.009 FPS. 0.95
FPS/0.009 FPS = 106.6 times lower velocity at the
screen surface than at the weir.
The low 0.009 FPS horizontal (created by the deflector
plate) exit velocity through the screen, positioned near
the liquid surface far from the settled solids, results in
less scouring and disturbance of the settled solids and
organic matter.
No physical weir allows a greater liquid depth and
360° horizontal flow of liquid moving towards the exit,
thus significantly larger cross-sectional area of liquid at
every flow radius. The larger the cross-sectional area
the slower the velocity for the same volume of liquid
exiting the system.
No Deflector
Deflector Plate
Previously described, but in summary it creates a
Plate
horizontal flow pattern versus a 180° flow pattern
towards a fix effluent weir.
Existing effluent weirs do not have horizontal deflector
plates or baffles as all flow must exit at the liquid
surface. There is a Stamford Baffle that was developed
to deflect the solids away from the effluent weirs as the
liquid rose from the sludge blanket level towards the
fixed effluent weir.
The Stamford baffle is a 45° plate to allow a vertical
flow vector. The invention's flat deflector plate
discourages all vertical flow patterns because the SBX
lowers with the liquid at the same rate to maintain a
fixed screen surface area thus not requiring any vertical
flow to exit.
Weir is located
Screen Box is
Water exiting near the center of the tank reduces short
at opposite end
positioned
circuit caused by placing a stationary weir near a side
of inlet
nearer the
wall. The wall reduces the cross-sectional area of the
center of the
water moving towards the exit causing higher velocities.
tank
[0103] Deflector Plate
[0104] A deflector plate 60 is placed below air scour 24 ′ to stop disturbance of settled solids that may be caused by vertical currents created by rising air bubbles from the air scour. Deflector plate 60 also increases the horizontal travel distance to the screen surface for any supracolloidal or colloidal solids that may be disturbed and start to move towards the tank discharge/screen.
[0105] The deflector plate is sized to extend several feet (some distance) past the edge of the screen box 12 . The actual size and shape of the deflector is dependent on the size and shape of the screen box and tank. The deflector plate edge nearest the tank wall may have a flexible sealing strip 62 mounted to the deflector plate if the distance to the wall and edge of the deflector plate is within 3 feet or the tank configuration requires such to stop transient rising currents. Sealing strip 62 connection to deflector plate 60 preferably is via slotted holes to allow the strip to be adjusted closer to or farther away from the wall and then tightened into final position. Sealing strip 62 should be within 1/16 inch or actually touching the tank sidewall to minimize vertical flow from below.
[0106] Deflector plate 60 preferably has drain ports 64 that open with low pressure to allow liquid above the deflector plate to pass through the plate when the screen box is moving upward. The drain ports may be low tension flap valves, molded polycarbonates with resilient properties, or the like.
[0107] Deflector plate 60 may be made of a flexible material that bends downward to allow liquid above the plate to flow easily off the edges. Such type of plate would obviate the need for the drain ports.
[0108] Preferably, the edges of deflector plate 60 facing the influent feed troughs 66 are raised at an angle to increase the travel distance and deflect supracolloidal and colloidal solids rising from below the deflector plate towards the influent feed troughs and away from the screen box as the screen box lowers in the liquid.
[0109] Screen Box Lifting Apparatus
[0110] A screen box lifting apparatus 28 may be pneumatic, hydraulic, winch and cable, or other mechanical apparatus to raise and lower the SBX 12 in a path perpendicular to the surface 30 the liquid 13 . The vertical (up/down) movement of the SBX allows the SBX system to be installed in relatively small clarifier tanks of circular or square geometry.
[0111] The currently preferred lifting apparatus 28 comprises a combined winch 32 , cable 34 , a pulley or pulleys 36 , and a winch drive 40 . The winch and cable provide an unlimited range of vertical motion, whereas the range of pneumatic, hydraulic, and mechanical actuators are limited (at this time) to about 8 feet due to lateral stresses created by the liquid movement. As development of pneumatic and hydraulic actuators proceeds, their incorporation in SBX systems may increase. An overhead pulley arrangement keeps the SBX assembly centered in the tank.
[0112] The lifting range of motion typically is from the bottom of the tank (likely low level is 1-5 feet) to 6 feet above the top of the tank.
[0113] Preferably, winch drive 40 is a vector motor, which can operate at 0-RPMs without overheating. A vector motor is desirable to ensure that the SBX descends at the same rate as the change in liquid level, which is critical to not disturbing the supracolloidal and colloidal constituents in the waste water, to promoting horizontal versus vertical currents towards the screen box, and to maintaining the liquid/screen contact area to control the screen solids loading rate.
[0114] As shown in FIGS. 20-21 , at the conclusion of a decant cycle, raising of SBX 12 starts slowly to reduce an energy spike/demand to conserve energy and then quickly accelerates to increase the exit velocity of the filtrate from inside SBX 12 , in the reverse direction through the screen, creating a vigorous backwash 42 of the screen. This action is initiated and controlled by control system 44 .
[0115] Cable 34 is connected to a baffled lifting column 28 for small units and to a support frame 46 of larger units. A ball and socket device 48 allows screen box 12 to move laterally as needed to reduce stress on the lifting device and to provide additional scouring of the screen box via slight horizontal motion caused by air scour and discharge hose rigidity.
[0116] Vertical guiderails are provided on the tank to guide SBX 12 in its vertical path. Guiderails interface with support frame 46 to align the SBX with the hood. The guiderails may be placed in various positions relative to the SBX depending on the configuration of the tank.
[0117] An encoder (not shown) tracks the vertical position of screen box 12 in the tank. Knowing the position of the screen box in the liquid is critical to knowing headloss through the screen and thus to having the correct amount of screen surface area in contact with the liquid for a specific screen loading rate and effluent flow rate. An algorithm to the SCADA provides control feedback on current RPM to slow or increase the motor to the proper speed.
[0118] Baffled Lifting Column and Stub Effluent Pipe for the SBX
[0119] Baffled Lifting Column 28 is a slotted or perforated circular pipe that is internally or externally threaded at the base to connect to the SBX Stub Effluent Pipe 52 . Lifting column(s) 28 (the long rectangular screen racks have (3) lifting columns and not all are used for lifting and all are centered and equally spaced in the screen racks) is centered in the SBX with openings 54 to encourage flow distribution through the screen. In rectangular or square frustum SBX shapes preferably there is more open area on the Baffled Lifting Column facing the box corners so as to pull more liquid from the corner or more distant screen. The open area closest to the screen will have the lowest surface area. If the screen is an equal distance from the Baffled Lifting Column, as in a cylindrical SBX, then the open area is the same around the circumference of the circular lifting column.
[0120] Preferably, the open area of the Baffled Lifting Column is lowest at the bottom and increases with elevation, creating headloss at the lower portion of the lifting column to equalize travel distance and pressure, and thus to equalize flow through the screen from the lowest point to the highest point of liquid contact.
[0121] Various configurations of suitable openings (vertical slots 54 tapering or of variable length, horizontal slots 54 a , holes 54 b , and screening 54 c ) are shown in FIGS. 4-10 .
[0122] Baffled Lifting Column 28 connects to SBX Stub Effluent Pipe 52 that connects directly to a flexible discharge hose 68 that directs the filtrate/effluent to effluent exit valve 18 .
[0123] Liquid Level and Effluent Flow Controls
[0124] Referring to FIGS. 15 and 17 - 20 , for gravity discharge flow applications, the flow rate of screened wastewater exiting the tank is controlled by a modulating exit valve 18 that opens or closes incrementally to maintain a target flow rate set by the controls 44 and measured by a flow meter 70 located upstream or downstream of the modulating exit valve.
[0125] The elevation of the discharge end of the screened wastewater pipe 72 is fixed as are the diameter and length of pipe connecting the SBX, SBX Stub Effluent Pipe, Discharge Hose, Flow Meter, and Modulating Valve to the discharge end. The piping and discharge location and elevation are a component on the infrastructure and not subject to change.
[0126] The change in liquid elevation within screen box 12 and the change in elevation of the screen box in the tank from a high liquid level 74 to a low liquid level 76 affects the hydraulic pressure in the screened effluent piping. The greater the elevation difference between inlet liquid elevation and discharge liquid elevation, the greater the pressure difference and thus flow. The lower the difference, the lower the pressure and thus flow.
[0127] Screen box 12 starts a decant cycle at the high liquid level 74 in the tank ( FIG. 17 ). Screen box 12 lowers at the same rate as the liquid level in the tank. When the tank liquid level reaches the low level set point, the screen box then is lifted upwards. The captured screened liquid exits outwards through the screen on the screen box. The faster the rise rate, the higher the exit velocity of the screened liquid moving through the screen. The high velocity creates a more vigorous backwash resulting in a more thorough cleaning of the screen.
[0128] The system employs a pair of pressure transducers 78 , 80 ( FIG. 15 ) disposed within the screen box and the tank, respectively. The control system 44 uses input from the flow meter 70 , pressure transducers 78 , 80 , and tank encoder to automatically position the screen box in the liquid to provide the defined screen surface area in contact with the liquid. The controls can automatically adjust the screen/liquid contact area to any desired value when the differential volume of the tank exceeds standard allowable deviations as in an abnormal flow condition that activates an alarm followed by adjustments in the target flow and decant cycles.
[0129] The flow rate of screened wastewater exiting the tank can also be controlled by a pump (not shown) instead of a modulating valve 18 . A pump may be used when there is inadequate active volume (volume between high and low liquid level—depth of decant) or the discharge elevation and the liquid level in the screen box is not adequate to flow by gravity at the required rate. A variable frequency drive (VFD) provides the incremental discharge flow control.
[0130] Discharge Hose
[0131] As described above, flexible discharge hose 68 is connected to pipe 52 near the bottom of the tank for gravity discharge (the more normal situation) and higher in the tank if the filtrate is pumped. The hose connection to the SBX 12 is to the internal flow distribution, lifting column 28 and SBX stub pipe 52 of a smaller single SBX unit or to the filtrate manifold 82 if multiple SBXs are used to provide more screen surface area. Hose 68 may have swivel connections to allow the hose to twist as the screen box moves up and down in the tank or the hose may be an accordion type of hose/duct to increase in length as the screen box rises up to above the tank to the hood or contracts as the screen box decants to the low liquid level in the tank. It is currently preferred to use an accordion type hose as it provides less disturbance of the settled sludge.
[0132] Screen Box Hood
[0133] An enclosing hood 84 that may contain a heater 86 , screen spray system 88 , and/or UV disinfection apparatus 90 is placed above the tank over each screen box 12 . Lifting cable 34 passes through an opening in the center of the hood. The hood 84 is mounted to the pulley support or other structure above the tank. The hood has an open bottom and hinged or flexible sides to allow access to the screen box, heater, screen spray system, UV disinfection, control instrumentation, etc. If UV is used, then a flexible protective seal (not shown) and sidewalls (not shown) and interlocking controls to deactivate the UV prior to lowering the SBX are provided to avoid accidental exposure.
[0134] In addition, in operation, hood 84 blocks the sun from the screen, preventing the growth of algae that could foul the screen.
[0135] Instruments and Controls Specific to Screen Box Functions
[0136] As described above, a pressure transducer (PT) 80 in the tank provides the controls with the liquid depth in the tank. A PT 78 in the screen box provides the liquid depth in the box. An encoder provides the position of the screen box in the tank.
[0137] These 3-inputs provide basic information necessary to perform the following functions:
[0138] 1. Screen Surface Area Adjustment
[0139] The screen surface area for each incremental elevation of screen is entered into the control system, as the screen sizes may vary. The operator sets a) a screen loading rate in GPM/SF, b) the desired Target Flow (TF) or discharge flow. These two variables then dictate the depth of the screen in the liquid to provide the correct screen surface area. The controls adjust the screen depth and thus surface area in the liquid to match the operator entered screen loading rate and effluent flow.
[0140] 2. Lowering of the Screen Box at the Start of a Decant Cycle
[0141] The air scour starts when the lower level of the screen reaches the liquid level. This is done to keep the liquid from flowing into the screen box without the air scour, to reduce fouling. Air scour could be activated at the start of decent but it consumes energy for no process benefit.
[0142] 3. Lifting and Flushing of the Screen Box at the End of a Decant Cycle
[0143] The lifting of the screen box was partially described above.
[0144] When the low liquid level is reached and it is time to raise the screen box out of the liquid, the effluent valve on the filtrate discharge piping is closed to prevent the screened wastewater/filtrate in the screen box from exiting via the discharge hose when the screen box is lifted. The screened wastewater reverses flow and exits through the screen, thus flushing the solids on the outside surface of the screen away from the screen surface.
[0145] With the effluent valve still closed, the screen box is lowered a set distance into the liquid in the tank to increase the volume of filtered liquid in the screen box. The entrance velocity of the liquid entering the screen box to fill the additional volume of filtered wastewater is low due to the slow descent and no discharge. This is done to prevent the solids laden lower liquid from fouling the screen. By refilling the screen box, the volume of backwash effluent is increased.
[0146] With the desired volume of filtered wastewater inside of the screen box, the screen is raised slowly at first for a short period of time and then quickly accelerates to increase the backwash flow velocity. As the screen box reaches a certain elevation, the vertical motion of the screen box slows and continues to slow as it reaches the hood and then stops at a set elevation or contact switch or other position detection device.
[0147] 4. Activation of Screen Spray System, Heater, UV Disinfection
[0148] The controls allow the operator to set the frequency of screen spray and UV disinfection cycles as needed based on a count of decant cycles. The systems will be activated when the screen is properly positioned and a contact switch in the hood is activated. The duration of the backwash in the hood is set by the amount of screen surface area and the available flow and pressure of the site.
[0149] The screen spray system will be automatically activated on the next cycle if the screen headloss reaches a user-defined set point.
[0150] The heater is temperature-controlled and deactivated to conserve energy when the screen box is not in the hood.
[0151] Low Profile Screen Box
[0152] Referring now to FIGS. 28-37 , a Low Profile Screen Box (LPSBX) 112 can be useful for applications of high flows, limited surface area to place a screen box, and/or shallow active volumes (the vertical distance between high and low water levels) of existing primary clarifiers. The low profile minimizes the height the SBX occupies from the bottom of the deflector plate to the top of the screen surface area.
[0153] Multiple screen boxes 112 or racks are ganged in parallel to provide the necessary screen surface area at a controlled screen loading rate.
[0154] The application requires the screen racks be placed close together with limited space between the racks ( FIGS. 29-31 ). This limited space can result in high horizontal velocities that would create uneven flow to and through the screen surface area, which uneven flow would result in fouling of high velocity areas of the screen. To create lower velocities and more uniform distribution of flow the screened surface of each rack is submerged with either a sealed top with air vents or an open top and solid vertical plates to enclose and seal the area above the screened surface. The LPSBX filtrate manifold 82 is connectible to flexible discharge hose 68 . This is done to increase the pathways and cross sectional area of flow to the center of the elongated racks which lowers the velocities to the screen, and the enclosed volume above the racks serves to increase the volume of screened liquid to backwash the screen. There are multiple screen racks 112 mounted to LPSBX filtrate manifold 82 , a deflector plate below 114 , and a modular lifting frame 116 .
[0155] The width of the rack 112 is determined by the open area between the rack and the filtrate manifold. The more open cross-sectional area connecting the rack to the manifold, the narrower the rack can be.
[0156] Referring to FIGS. 36-39 , LPSBX filtrate manifold 82 comprises a central drain channel 83 terminating in an outlet 85 connectible to a flexible drain hose 68 ( FIG. 13 ) via fitting 52 ( FIG. 1 ) as just described. Central drain channel 83 is transected by a plurality of feeder channels 87 that drain into central drain channel 83 . In turn, the multiple screen racks 112 transect and drain into feeder channels 87 via mating ports 89 that are sealed between racks 112 and channels 87 .
[0157] Referring to FIGS. 29-31 , the narrow vertical ends of the racks 112 may be rounded 12 a or triangular 12 b to reduce turbulence and promote laminar horizontal flow towards the center of the rack thus reducing vertical flows from top and bottom.
[0158] Referring now to FIGS. 32-37 , LPSBX 112 is cleaned and sanitized in a manner similar to the cleaning of a single SBX 12 as described above.
[0159] A spray header assembly 300 comprises a plurality of spray elements 302 (equal to the number of SBXs) connected in parallel via piping 304 to one or more water inlets 306 . Assembly 300 is mounted in a openable hood 308 that in turn is mounted to a framework 310 for attachment to a clarifier tank (not shown) containing LPSBX 112 . Assembly 300 and LPSBX are aligned such that upon raising of the LPSBX the spray elements enter the LPSBX or SBX units, spraying the inside screen surface outward to displace solids on the exterior screen face. The raising and lowering cycle may be repeated as may be needed for proper cleaning of the screens. The cleaning effluent drains into the deflector plate 114 and through openings therein into the clarifier tank below.
[0160] Installation into a Prior Art System
[0161] Referring now to FIGS. 26-27 a , an SBX system in accordance with the present invention may be installed in existing clarifiers 200 of conventional design or the new clarifier design. The preferred installation is the new clarifier design that comprises a single primary settling tank 202 that performs grit removal, flow equalization, primary clarification, and fine screening such as is disclosed in the above-incorporated US patents.
[0162] The location of the SBX 12 in a retrofit of a conventional clarifier is dependent on the size and shape of the clarifier tank, the configuration of the internal sludge and scum mechanisms, a mapping of the COD within the clarifier under different flow conditions, the settling characteristics of the solids, peak/average/minimum flows, and hydraulic profile. In some cases the existing sludge withdrawal mechanisms, scum troughs, and effluent weirs may need to be modified.
[0163] In the new style clarifiers, the SBX is placed in the center of the tank over the sludge hoppers, equal distance from the influent feed trough. This is done because most solids have settled in the center of the tank in the sludge hoppers as a result of feeding equal flow, equal distances from opposite sides of the tank towards the center, at equal velocities. The SBX deflector plate prevents the disturbance of the solids below the plate. There will be some slight disturbance of the light solids from the invention moving downward. These disturbed solids then must travel both vertically and horizontally around the deflector plate. This additional travel distance and time at a low exit velocity will reduce the amount of solids reaching the screen.
[0164] The SBX has several different configurations useful for different flow ranges, types of liquid being decanted, and new or old style clarifier.
[0165] The installation of the SBX into an existing clarifier requires modifications to the operation of the conventional clarifier to provide beneficial flow patterns similar to the new style clarifier. The influent flow is directed to the clarifiers that have a low liquid level. The clarifiers with a high liquid level are in the process of resting or decantation. This is accomplished by alternating the clarifier influent gates or valves from open to close through the inventions' control system. Actuators may be affixed to the existing gates or valves to allow automatic operation. Individual pumps dedicated to specific tanks may also be used.
[0166] There is no decanting or discharge during the fill cycle because energy imparted into the flowing liquid keeps the BOD in suspension. Preferably, after filling of the tank a rest period with no discharge allows the fluid inertia and energy to dissipate, improving the settling of the supracolloidal and colloidal solids. Such a rest period can assist in achieving solids removal levels of about 85%. The exception to this operational mode is during high flow events in which the sewage is highly diluted, having a lower solids and BOD concentration, than both tanks may be operated to handle the excessive volume of liquid. Currently such events wash the settled solids out of the clarifier and aeration tanks and into the receiving body of water or into the secondary treatment process. The physical barrier of the SBX contains the solids within the clarifier tank. There may also be redundant SBX systems within each clarifier tank that can be brought into operation to assist in screening of the excessive flow. This is automatically done via the SBX control system detecting and quantifying the excessive flow and deviations to normal or experienced flow patterns.
[0167] The SBX moves vertically with no pivot at the base discharge so there is no horizontal movement. This makes the horizontal footprint of the invention smaller so it can fit into narrow deep tanks.
[0168] FIGS. 26-26 a show that a prior art pivoting weir 100 occupies a footprint that may be fully half of a clarifier tank. FIGS. 27-27 a show that an SBX 12 in accordance with the present invention may occupy a footprint scarcely larger than the diameter of the SBX. In a clarifier retrofit, the pivoting weir 100 is simply removed at the pipe pivot joint 102 and replaced by connection of the collapsible SBX hose 68 .
[0169] From the foregoing description, it will be apparent that there has been provided an improved decanter system for a wastewater clarifier. Variations and modifications of the herein described decanter system, in accordance with the invention, will undoubtedly suggest themselves to those skilled in this art. Accordingly, the foregoing description should be taken as illustrative and not in a limiting sense. | The present invention relates to a vertically adjustable screened decanter system to replace prior art stationary or pivoting effluent weirs in water clarifiers and settling basins. The screened decanter has no physical weir and relies instead on maintaining a desired flow rate by controllably varying the depth of immersion of a screened box. The decanter is periodically raised into a hood that provides spray cleaning and disinfection of the screened box. The system is capable of removing up to 85% of the BOD in a wastewater stream. | 2 |
FIELD OF THE INVENTION
The present invention is directed to a method and apparatus for pelletizing a petroleum resid wherein the resid is prilled in a molten state using a rotating prilling head, liquid particles of the resid made by the prilling head are formed into spheres before solidifying, and the spherical particles are then quenched and solidified in substantially spherical shape. The present invention is also directed to petroleum resid pellets that can be stored and/or shipped at ambient temperatures. The invention is also directed to hardening a relatively soft petroleum resid by controlled air oxidation at elevated temperatures to form a hard petroleum resid that can be pelletized and stored/shipped at ambient temperature.
BACKGROUND OF THE INVENTION
The residue from petroleum distillation has a wide number of uses, including paving asphalt and fuel. Paving grade asphalt used in road construction must meet a number of specifications, including the latest SHRP specification, viscosity (usually 200-5000 poises at 60° F.), penetration (usually greater than 30 to 200 dmm), penetration ratio 15° F./25° F. (usually above about 0.3), ductility, temperature susceptibility, and others.
Contacting the resid fraction of petroleum with air at an elevated temperature, also referred to as “air blowing,” is a conventional way to improve the characteristics of certain grades of resid to make them suitable for use as a paving asphalt. However, the prior art does not appear to disclose the practical application of air blowing a relatively soft resid to obtain a relatively hard resid that can be pelletized for storage and/or shipment. As used in the present specification and claims, a “soft resid” or a “low softening point temperature” refers to a petroleum residue having a penetration above 0 and Ring and Ball (R&B) softening point temperature below 200° F. A “hard resid” or a “high softening point temperature” refers to a petroleum residue with a penetration of essentially 0 and R&B softening point temperature above 200° F.
Representative references disclosing resid or asphaltene air blowing equipment and methodology include U.S. Pat. No. 2,616,837 to Roediger; U.S. Pat. No. 2,627,498 to Fink et al; U.S. Pat. No. 2,861,939 to Biribauer et al; U.S. Pat. No. 2,889,296 to Morris et al; U.S. Pat. No. 3,462,359 to Fauber; U.S. Pat. No. 3,598,716 to Fauber; U.S. Pat. No. 3,751,278 to Alexander; U.S. Pat. No. 3,779,892 to Forster et al; U.S. Pat. No. 3,868,315 to Forster et al; U.S. Pat. No. 3,935,093 to Senolt et al; U.S. Pat. No. 3,989,616 to Pagen et al; U.S. Pat. No. 4,052,290 to Cushman et al; U.S. Pat. No. 4,207,117 to Espenscheid et al; U.S. Pat. No. 4,283,230 to Clementoni et al; U.S Pat. No. 4,332,671 to Boyer; U.S. Pat. No. 4,933,067 to Rankel; U.S. Pat. No. 4,975,176 to Begliardi et al; U.S. Pat. No. 5,228,977 to Moran et al; U.S. Pat. No. 5,320,739 to Moran et al; U.S. Pat. No. 5,932,186 to Romine et al; and U.S. Pat. No. 5,939,474 to Gooswilligen et al. Air blowing technology is commercially available under the trade designation BITUROX, for example.
In contrast to paving asphalt, the specifications for fuel grade petroleum resid that is burned as a fuel are much less stringent. The resid generally has a higher calorific value and better combustion characteristics compared to coal and petroleum coke, which is why resid has been added to coal and coke as fuel additive to aid combustion. However, heavy resid with a low softening point temperature is difficult to store and/or transport without significant handling and packaging requirements. Over time, even when they initially may appear to be solid at ambient conditions, these low-softening-point-materials exhibit liquid flow characteristics at elevated temperatures. These materials have typically been transported as a semi-solid product, as a neat liquid product, or as a cutback liquid product. The semi-solid form must be shipped in a closed container to prevent leakage and spillage, is usually reheated prior to use, and the high cost of packaging and handling the material in this manner usually limits application to relatively small volumes of product.
As a neat liquid product, heavy resid is maintained at elevated temperatures sufficient to keep the material in a liquid state. This method is also expensive and has limited practical application.
As a cutback liquid product, heavy resid is mixed with light hydrocarbon cutterstocks to maintain the mixture in a liquid state at lower temperatures. As a result, the lighter hydrocarbons with which the resid is blended are substantially downgraded in value.
A pelletized resid that remains solid would be free flowing and could be readily stored, packaged, transported and handled. Previous attempts at pelletizing resid with a low softening point temperature have relied on encapsulating the resid with a solid coating. Coating the resid complicates the encapsulating process, results in a compositionally heterogeneous product, adds cost due to the generally expensive nature of the coating material, is not always effective due to rupture or breakage of the coating and/or to dissolution of the coating by water if the coating is water soluble, and the coating can adversely affect the combustion characteristics of the resid. Representative references teaching various encapsulation apparatus and methodology include U.S. Pat. No. 3,015,128 to Somerville; U.S. Pat. No. 3,310,612 to Somerville; U.S. Pat. No. 4,123,206 to Dannelly; U.S. Pat. No. 4,128,409 to Dannelly; U.S. Pat. No. 4,386,895 to Sodickson; and U.S. Pat. No. 5,637,350 to Ross.
U.S. Pat. No. 4,931,231 to Teppo et al discloses a method for manufacturing discrete pellets of asphaltic material by flowing the asphaltic material in molten form as an elongated annular stream directly into cooling water to solidify and shatter the elongated stream into discrete solid particles. The particles formed as a result of shattering are not spherical and have undesirable flow and/or handling characteristics. For example, the particles may be dust-free when made, but because of any jagged edges, might result in formation of considerable dust upon handling.
U.S. Pat. No. 3,877,918 to Cerbo discloses apparatus for producing spherical glass particles by centrifugally projecting solid crushed glass particles into the draft tube of a bead furnace using a rotary receptacle. The rotary receptacle forms a cloud of evenly dispersed solid glass particles, which are directed upwardly into the expansion chamber of the furnace to heat and shape the glass particles by surface tension into spheres.
The prior art does not appear to disclose a method or apparatus for making spherical petroleum resid pellets by feeding the resid in a molten state to a rotating prilling head, allowing the resid discharged from the prilling head to break into particles and form into spheres due to the surface tension of the molten resid as the particles pass by gravity through a high temperature zone, and then quenching the molten material in a cooling medium to solidify the particles in their substantially spherical form. Nor does there appear to be any prior disclosure of substantially spherical, compositionally homogeneous (uncoated) petroleum resid pellets having a high softening point temperature, nor of a method or apparatus for making spherical resid pellets for ambient temperature storage and shipment for use in combustion processes as a fuel or fuel additive.
SUMMARY OF THE INVENTION
The present invention produces substantially spherical particles from a material such as petroleum resid that is normally solid at ambient temperature, but can be liquefied at an elevated temperature. The present invention produces a compositionally homogeneous pelletized petroleum resid product suitable for ambient-temperature storage and shipment prior to an end use. The pellets are relatively hard and have a softening point temperature above 200° F. so that they do not stick together at ambient storage and transportation temperatures. If the resid feedstock is not sufficiently hard, it can be hardened by oxidation with air at elevated temperature. The resid is prilled at molten temperatures using a rotating prilling head that discharges the molten resid into a high temperature vapor space. As the resid is thrown away from the prilling head and falls by gravity, it breaks into small pieces that form into spheres while liquid. After the spheres are formed in a liquid state, the pellets are cooled and solidified, for example, by passing the spheres through a water mist and collecting them in a water bath.
Broadly, the invention provides a process for pelletizing a petroleum resid. The process comprises (1) heating the resid to a temperature at which it is in a liquid state, (2) continuously feeding the molten resid to an inlet of a centrifugal prilling head comprising a plurality of radially arrayed discharge orifices in fluid communication with the inlet, (3) rotating the prilling head to discharge the resid from the orifices into free space near an upper end of a pelletizing vessel having a diameter larger than a throw-away diameter of the discharged resid, (4) allowing the discharged resid to break apart and form into substantially spherical pellets in a high temperature zone of the pelletizing vessel at which the resid is liquid, and to fall downwardly into contact with a cooling medium in which the resid is insoluble and which is maintained at a temperature effective to cool/solidify the pellets, (5) withdrawing a mixture of the solidified pellets and the cooling medium from the pelletizing vessel, and (6) substantially separating the pellets from the cooling medium.
The discharge orifices in the prilling head are preferably arrayed at a circumference of the prilling head in a plurality of vertically spaced upper and lower rows. The lower row or rows can be disposed at a smaller diameter from the axis of rotation of the prilling head than the upper row or rows. The prilling head preferably has a circumference tapered from an uppermost row of orifices to a lowermost row, and can be rotated at from about 10 to about 5000 rpm. The prilling head preferably has a diameter from about 2 inches to about 5 feet, the orifices a diameter from about {fraction (1/32)}-inch to about 1 inch and a production capacity of from about 1 to about 1000 lbs/hr of resid per orifice, the throw-away diameter from about 1 foot to about 15 feet, and the pellets a size range from about 0.1 mm to about 10 mm.
The cooling medium is preferably water, and the water bath is maintained in the pelletizing vessel at a temperature from about 40° to about 190° F. The water is preferably introduced into the pelletizing vessel as an inwardly directed spray, e.g. a fine mist, in a cooling zone above the bath to at least partially cool the spherical pellets before they enter the bath. The slurry withdrawn from the pelletizing vessel is preferably no more than about 50° F. warmer than the water introduced into the cooling zone. The process can also include the steps of collecting water from the separation step, and filtering, cooling, and recirculating the cooled water to the cooling zone.
The process can also include the step of venting vapor near an upper end of the pelletizing vessel and/or the step of heating an upper end of the pelletizing vessel to maintain a substantially constant temperature zone in the vicinity of the prilling head. The process can further comprise the step of transporting the recovered pellets at ambient temperature to a location remote from the pelletization vessel where the pellets are used for combustion, as a combustion improver or additive to coke and/or coal, in admixture with a cutterstock for fuel oil, or the like.
The petroleum resid fed to the heating step preferably has a penetration of essentially 0 and a softening point temperature from 200° to 400° F., more preferably having a softening point temperature from about 230° to about 350° F. The resid is preferably obtained as the asphaltene-rich fraction from a solvent deasphalting process. The resid feed is preferably heated to a temperature from about 350° to about 700° F., and the pellets recovered from the separation can have a residual water content of from 0.1 to 10 weight percent. The process can also include burning the transported resid pellets, for example, as a combustion fuel, as an additive in the combustion of coal and/or petroleum coke or as a blend component with cutterstock in a fuel oil.
The process can further comprise the step of contacting a soft petroleum resid with air at a temperature from about 350° to about 700° F. for a period of time effective to reduce the penetration of the resid to essentially 0 and increase the softening point temperature to above 200° F. to form a hard resid suitable for use as the resid feed for prilling. The soft resid can be obtained as atmospheric tower resid or the asphaltene-rich fraction from solvent deasphalting of a petroleum residue, especially propane deasphalting. The air contacting step is preferably for a period of time from about 2 to about 5 hours.
In another aspect of the invention, there is provided a process for making petroleum resid pellets from a soft petroleum resid. The process includes contacting a soft resid having a penetration greater than 0 and a softening point temperature below about 200° F. with air at a temperature from about 350° to about 700° F. for a period of time effective to form a hard resid having a penetration of essentially 0 and a softening point temperature above 200° F., and forming the hard resid into pellets. The process can also include burning the pellets as a fuel or fuel additive, for example.
In a further aspect of the invention, there is provided a pelletizer for making spherical pellets from a material such as petroleum resid which is normally solid at ambient temperature, but which can be liquefied at elevated temperature. The pelletizer includes an upright pelletizing vessel having an upper prilling zone, a hot sphere-forming zone below the prilling zone, a cooling zone below the sphere-forming zone, and a lower liquid cooling bath below the cooling zone. A prilling head is centrally disposed in the prilling zone, and is rotatable along a vertical axis. The prilling head has a plurality of discharge orifices for throwing the molten materially radially outwardly. A throw-away diameter of the prilling head is less than an inside diameter of the pelletizing vessel. A process line is provided for supplying the material to the prilling head. A vertical height of the sphere-forming zone is sufficient to allow liquid material discharged from the prilling head to form into a substantially spherical shape while in the liquid state. Nozzles can be provided for spraying liquid cooling medium, preferably water in the form of a mist, inwardly into the cooling zone to cool and solidify at least an outer surface of the spheres to be collected in the bath. Another line is provided for supplying water to the nozzles and the bath to maintain the relatively low temperature of the bath in the pelletizing vessel. A further line is provided for withdrawing a slurry of the pellets in the bath water. A liquid-solid separator is provided for dewatering the pellets from the slurry.
The pelletizer can also include an oxidation vessel for contacting a soft resid, having a penetration greater than 0, and preferably less than 100 dmm, with air at a temperature from about 350° to about 700° F. for a period of time effective to reduce the penetration of the resid to essentially 0 and to increase the softening point temperature to above 200° F. to form a hard resid suitable for feed to the prilling head. The pelletizer can preferably further include a solvent deasphalting unit for obtaining the soft resid as the asphaltene fraction from solvent deasphalting of a petroleum residue.
The discharge orifices of the prilling head are preferably arrayed at a circumference of the prilling head in a plurality of vertically spaced upper and lower rows wherein the lower row or rows are disposed at a smaller diameter from the axis of rotation of the prilling head than the upper row or rows. The prilling head can have a circumference tapered, either continuously or stepped, from an uppermost row at a relatively large diameter to a lowermost row at a relatively small diameter. In one alternative embodiment, the prilling head preferably comprises a plurality of rings of different diameter with orifices formed in an outer circumference of each ring, wherein the rings are secured to the prilling head in a descending fashion, each successively lower ring having a smaller diameter than the preceding ring. The pelletizer preferably has a drive for rotating the prilling head at from about 10 to about 5000 rpm wherein the prilling head has a diameter from about 2 inches to about 5 feet, and wherein the orifices have a diameter from about {fraction (1/32)}-inch to about 1-inch and a production capacity of from about 1 to about 1000 lbs/hr of molten material per orifice.
The cooling medium is preferably water and the pelletizer also preferably includes a cooler for maintaining the bath in the pelletizing vessel at a temperature from about 40° to about 190° F. The aqueous bath preferably contains a minor amount of a non-foaming surfactant. The vessel preferably has a conical bottom containing the bath and a discharge at a lower end of the conical bottom for feeding the slurry into the withdrawal line. A filter can be provided for filtering water recovered from the liquid-solid separator, a cooler provided for cooling the filtered water and a recirculation line provided for recirculating the cooled water to the supply line.
A vent line is preferably provided for withdrawing vapor from the pelletizing vessel near an upper end thereof. A heater can also be provided for heating an upper end of the vessel to maintain a substantially constant temperature zone adjacent the prilling head, particularly during startup operations. In one preferred embodiment, a line is provided for introducing steam into the sphere-forming zone.
The liquid-solid separator preferably comprises a vibrating screen. The pelletizer can further comprise a conveyor belt for transporting the pellets from the vibrating screen to ambient temperature storage, packaging and/or shipment.
In another aspect, the present invention provides substantially spherical, homogeneous petroleum resid pellets suitable for combustion having a size range between 0.1 and 10 mm, a penetration of essentially 0, a softening point temperature from about 200° to about 400° F., preferably from about 230° to about 350° F., a residual water content of from 0.1 to 10 weight percent, and a sulfur content less than 10 weight percent. The resid pellets can comprise a hard resid produced by a process comprising contacting a soft resid with air at an elevated temperature for a period of time effective to convert the soft resid to hard resid, preferably from 2 to 5 hours.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified process flow diagram of one embodiment of the method of pelletizing a hard petroleum resid according to the present invention.
FIG. 2 is a simplified process flow diagram of an alternate embodiment of the method of FIG. 1 including air oxidation of a soft resid to convert it to hard resid prior to prilling.
FIG. 3 is a simplified flow diagram of a pelletizer according to an embodiment of the invention.
FIG. 4 is a simplified schematic of one embodiment of a prilling head according to the present invention.
FIG. 5 is a simplified schematic of an alternative embodiment of a prilling head according to the present invention.
DETAILED DESCRIPTION
The petroleum resids which are suitable for pelletization in accordance with the present invention include any asphaltene-rich material, particularly the asphaltene fraction from solvent deasphalting with propane or another solvent as practiced in solvent deasphalting process technology commercially available under the trade designations ROSE, DEMEX, SOLVAHL and the like. The term “resid” as used in the present specification and claims also encompasses other asphaltene-containing sources from petroleum resids such as, for example, atmospheric tower bottoms, vacuum tower bottoms, visbreaker residue, thermal cracker residue, soaker residue, hydrotreater residue, hydrocracker residue, and the like. The resid can have a softening point temperature from 0° to 400° F., a penetration of from 0 to 100 dmm, and a sulfur content from 0 to 10 weight percent. Resids from propane deasphalting and atmospheric tower bottoms typically have a softening point temperature below 200° F. Representative petroleum resids and their properties are listed in Table 1 as follows:
TABLE 1
Source or
R&B
Penetration
Sulfur
Resid
or process
(°0 F.)
(dmm)
(wt %)
Asphaltenes
Solvent deasphalting
0-400
0-100
0-10
Propane deasphalting
0-200
0-100
0-10
ROSE process
0-400
0-100
0-10
DEMEX process
0-400
0-100
0-10
SOLVAHL process
0-400
0-100
0-10
Atmospheric
Atmospheric tower
0-200
0-100
0-10
Vacuum
Vacuum tower
0-400
0-100
0-10
Visbroken
Visbreaker
0-400
0-100
0-10
Thermal/
Thermal cracker
0-400
0-100
0-10
Catalytic
Soaker
0-400
0-100
0-10
Hydrotreater
0-400
0-100
0-10
Hydrocracker
0-400
0-100
0-10
Petroleum resids can be divided into two groups, soft and hard resids, that are differentiated from each other by means of their R&B softening point temperatures as measured per ASTM D3461-85 and penetration as measured by ASTM D5. The R&B softening point temperatures of soft resids will generally be below 200° F. and their penetrations greater than 0; the hard resids will have R&B softening point temperatures of approximately 200° F. and higher and a penetration of essentially 0. The R&B softening point temperature for a petroleum resid is defined as the temperature at which the viscosity of the resid is approximately 1,000,000 cSt and phase transformation from solid to semisolid occurs. The pellets produced from the softer resids may stick together and may have poor storage and transportation capabilities at ambient conditions. Thus, the soft resids are generally unsuitable for pelletization commercially unless they are pretreated to chemically modify (by air oxidation or another appropriate process) these materials or encapsulate the resulting pellets with an impervious coating. In contrast, the pellets produced from hard resids can have good storage and transportation capabilities without pretreatment.
According to the present invention, the soft resids are first oxidized in a conventional air blowing reactor typically operating at mild pressure (<50 psig) and moderate temperature (350° to 700° F.) by sparging air. The resid hardens with air blowing time at constant temperature and air flow rate per unit weight. The typical air blowing time is 2 to 5 hours. However, the air blowing time can be reduced by increasing the temperature and/or the air flow rate per unit weight of the resid. Some of the resins present in the soft resid are oxidized and converted into asphaltenes. Some of the resins and asphaltenes are converted into light hydrocarbons, light hydrocarbon liquids and off gases (containing CO, CO 2 , gaseous hydrocarbons and H 2 ). The air blowing process generally reduces the heating value of the resid, but increases the R&B softening point temperature and oxygen content of the resid. The oxidized resid with R&B above 200° F. is suitable for pelletization.
This invention is a process to produce pellets or prills from both soft and hard petroleum resids. In accordance with one embodiment of the invention, the hard resid 10 , i.e., having an initial R&B softening point temperature above 200° F., can be pelletized directly, i.e. without any pretreatment (refer to FIG. 1 ). The soft resid 12 is preferably first subjected to air oxidation or blowing 14 at elevated temperature and mild pressure to convert it to a hardened resid with a R&B softening point temperature of 200° F. and above to render it more suitable for pelletizing (FIG. 2 ). The pelletization of both the hard and hardened soft resids is performed using a pelletizing step 16 employing a centrifugal prilling device. The centrifugal prilling device has a high prilling capacity, flexibility to produce pellets of various sizes and from a variety of resids, ease of operation, self-cleaning capability, and ease of startup and shut down.
The pelletization 16 nproduces pellets that are substantially spherical with good storage, transportation and fuel characteristics. The pellets from the pelletization 16 are optionally sent to storage 18 (FIG. 1) on a pad or in a pit, silo, tank or drum, or storage can include packaging in bags, boxes, drums or the like. The pellets can then be sent for shipment 20 by truck, rail car, ship, barge or the like. The pellets can also be subject to storage after shipment as seen in FIG. 2 . Desirably, the pellets are then burned with air in conventional combustion equipment 22 appropriately designed for resid combustion as is known in the art to obtain a flue gas 24 from which heat is typically recovered. The invention is not necessarily, however, limited to combustion of the pellets, which may have other utilities.
With reference to FIG. 3, the hard resid 10 (or hardened soft resid from an air blowing unit or other processing units that can produce hardened soft resids) is fed to surge drum 30 . The purpose of the surge drum 30 is to remove residual solvent contained in the resid (e.g., from asphaltenes recovered from solvent deasphalting processes), which is vented overhead in line 32 , and also to provide a positive suction head for positive displacement pump 34 . The positive displacement pump 34 delivers the resid to the pelletizer vessel 36 at a desirable flow rate. A spill back arrangement, including pressure control valve 38 and return line 40 , maintains resid levels in the surge drum 30 and also adjusts for the fluctuations in pellet production. The resid from the positive displacement pump 34 flows through resid trim heater 42 where the resid is heated to the desired operating temperature for successful pelletization. A typical outlet temperature from the resid trim heater 42 ranges from about 350° to about 600° or 700° F. depending on the viscosity and R&B softening point temperature of the resid.
The hot resid flows via line 44 to the top of the pelletizer vessel 36 where it passes into the rotating prilling head 46 . The rotating head 46 is mounted directly on the top of the pelletizer vessel 36 and is rotated using an electrical motor 48 or other conventional driver. The rotating head 46 is turned at speeds in the range of from about 10 to about 5000 RPM.
The rotating head 46 can be of varying designs including, but not limited to the tapered basket 46 a or multiple diameter head 46 b designs shown in FIGS. 4 and 5, respectively. The orifices 50 are evenly spaced on the circumference of the heads 46 a , 46 b in one or more rows in triangular or square pitch or any other arrangement as discussed in more detail below. The orifice 50 diameter can be varied from about 0.03 to about 1 inch (about 0.8 to 25 mm) to produce the desired pellet size and distribution. The combination of the rotating head 46 diameter, the RPM, the orifice 50 size and fluid temperature (viscosity) controls the pellet size and size distribution, resid throughput per orifice and the throw-away diameter of the pellets. As the resid enters the rotating head 46 , the centrifugal force discharges long, thin cylinders of the resid into the free space at the top of the pelletizer vessel 36 . As the resid travels outwardly and/or downwardly through the pelletizer vessel 36 , the resid breaks up into spherical pellets as the surface tension force overcomes the combined viscous and inertial forces. The pellets fall spirally into the cooling water bath 52 (see FIG. 3) which is maintained in a preferably conical bottom 54 of the pelletizer vessel 36 . The horizontal distance between the axis of rotation of the rotating head 46 and the point where the pellet stops travelling away from the head 46 and begins to fall downwardly is called the throw-away radius. The throw-away diameter, i.e. twice the throw-away radius, is preferably less than the inside diameter of the pelletizing vessel 36 to keep pellets from hitting the wall of the vessel 36 and accumulating thereon.
Steam, electrical heating coils or other heating elements 56 may be provided inside the top section of the pelletizer vessel to keep the area adjacent the head 46 hot while the resid flows out of the rotating head 46 . Heating of the area within the top section of the pelletizer vessel 36 is used primarily during startup, but can also be used to maintain a constant vapor temperature within the pelletizer vessel 36 during regular operation. If desired, steam can be introduced via line 57 to heat the vessel 36 for startup in lieu of or in addition to the heating elements 56 . The introduction of steam at startup can also help to displace air from the pelletizer vessel 46 , which could undesirably oxidize the resid pellets. The maintenance of a constant vapor temperature close to the resid feed 44 temperature aids in overcoming the viscous forces, and can help reduce the throw-away diameter and stringing of the resid. The vapors generated by the hot resid and steam from any vaporized cooling water leave the top of the vessel 36 through a vent line 58 and are recovered or combusted as desired.
The pellets travel spirally down to the cooling water bath 52 maintained in the bottom section of the pelletizer vessel 36 . A water mist, generated by spray nozzles 60 , preferably provides instant cooling and hardening of the surface of the pellets, which can at this stage still have a molten core. The surface-hardened pellets fall into the water bath 52 where the water enters the bottom section of the pelletizer vessel 36 providing turbulence to aid in removal of the pellets from the pelletizer vessel 36 and also to provide further cooling of the pellets. Low levels (less than 20 ppm) of one or more non-foaming surfactants from various manufacturers, including but not limited to those available under the trade designations TERGITOL and TRITON, may be used in the cooling water to facilitate soft landing for the pellets to help reduce flattening of the spherical pellets. The cooling water flow rate is preferably maintained to provide a temperature increase of from about 10° to about 50° F., more preferably from about 15° to about 25° F., between the inlet water supply via lines 62 , 64 and the outlet line 66 .
The pellets and cooling water flow as a slurry out of the pelletizer vessel 36 to a separation device such as vibrating screen 68 where the pellets are dewatered. The pellets can have a residual water content up to about 10 weight percent, preferably as low as 1 or even 0.1 weight percent or lower.
The pellets can be transported to a conventional silo, open pit, bagging unit or truck loading facility (not shown) by conveyer belt 70 . The water from the dewatering screen 68 flows to water sump 72 . The water sump 72 provides sufficient positive suction head to cooling water pump 74 . The water can alternatively be drawn directly to the pump suction from the dewatering screen (not shown). The cooling water is pumped back to the pelletizer through a solids removal element 76 such as, for example, a filter where fines and solids are removed. The cooling water is cooled to ambient temperature, for example, by an air cooler 78 , by heat exchange with a refinery cooling water system (not shown), or by other conventional cooling means, for recirculation to the pelletization vessel 36 via line 80 .
Typical operating conditions for the pelletizer of FIG. 3 are as shown in Table 2 below:
TABLE 2
Typical Pelletizer Operating Conditions
Condition
Range
Preferred Range
Resid feed temperature
350° to 700° F.
400 to 600° F.
Pressure
1 atmosphere to 200 psig
Less than 50 psig
Head Diameter, in.
2 to 60
2 to 36
Head RPM
10 to 5000
200 to 3000
Orifice Size, in.
0.03 to 1
Less than 0.5
Orifice Pitch
Triangular or square
Orifice capacity
1 to 1000 lbs/hr per orifice
Up to 400 lbs/hr
per orifice
Throw-away diameter
1 to 15 feet
2 to 10 feet
Cooling water in, ° F.
40 to 165
60 to 140
Cooling water out, ° F.
70 to 190
75 to 165
Cooling water ΔT, ° F.
10 to 50
15 to 25
Pelletsize, mm
0.1 to 10
0.5 to 5
The present invention discloses the use of the centrifugal extrusion device 46 to pelletize petroleum resids. The centrifugal extrusion device 46 results in a low-cost, high-throughput, flexible and self-cleaning device to pelletize the resids. The orifices 50 are located on the circumference of the rotating head 46 . The number of orifices 50 required to achieve the desired production is increased by increasing the head 46 diameter and/or by decreasing the distance between the orifices 50 in a row and axially spacing the orifices 50 at multiple levels. The orifices 50 can be spaced axially in triangular or square pitch or another configuration.
The rotating head 46 can be of varying designs including, but not limited to the tapered basket 46 a or multiple diameter head design 46 b shown in FIGS. 4 and 5, respectively. The combination of the head 46 diameter and the speed of rotation determine the centrifugal force at which the resid extrudes from the centrifugal head 46 . By providing orifices 50 at different circumferences of the head 46 b , for example, it is believed that any tendency for collision of molten/sticky particles is minimized since there will be different throw-away diameters, thus inhibiting agglomeration of resid particles before they can be cooled and solidified. If desired, different rings 47 a-c in the head 46 b can be rotated at different speeds, e.g. to obtain about the same centrifugal force at the respective circumferences.
Besides speed of rotation and diameter of the head 46 , the other operating parameters are the orifice 50 size, resid temperature, surrounding temperature, size of the resid flow channels inside the head 50 (not shown), viscosity and surface tension of the resid. These variables and their relation to the pellet size, production rate per orifice, throw-away diameter and the jet breaking length are explained below.
The orifice 50 size affects the pellet size. A smaller orifice 50 size produces smaller pellets while a larger size produces larger pellets for a given viscosity (temperature), speed of rotation, diameter of the head 46 and throughput. The throw-away diameter increases with a decrease in orifice 50 size for the same operating conditions. Adjusting the speed of rotation, diameter of the head 46 and throughput, the pellets can be produced with a varied range of sizes. Depending on the throughput, the number of orifices 50 can be from 10 or less to 700 or more.
The speed of rotation and diameter of the centrifugal head 46 affect the centrifugal force at which the extrusion of the resid takes place. Increasing the RPM decreases the pellet size and increases the throw-away diameter, assuming other conditions remain constant. Increase in head 46 diameter increases the centrifugal force, and to maintain constant centrifugal force, the RPM can be decreased proportionally to the square root of the ratio of the head 46 diameters. For a higher production rate per orifice 50 , greater speed of rotation is generally required. The typical RPM range is 10 to 5000. The centrifugal head 46 diameter can vary from 2 inch to 5 feet in diameter.
The viscosity of the resid generally increases exponentially with a decrease in temperature. The resid viscosities at various temperatures can be estimated by interpolation using the ASTM technique known to those skilled in the art, provided viscosities are known at two temperatures. The viscosity affects the size of the pellets produced, the higher viscosity of the resid producing larger pellets given other conditions remain constant.
EXAMPLES 1 AND 2
Experiments were performed with two petroleum resids produced from solvent deasphalting, which had R&B softening point temperatures of 265° and 292° F. The experimental setup consisted of a feed tank oven, pelletizer resid pump, heated feed line, seals to transfer the resid to the centrifugal head, a multi-orifice centrifugal head, motor and belt to rotate the head, and a pellet collection tray. The resid was heated to the desired operating temperature in the drum oven and pumped to the rotating centrifugal head by the pelletizer resid pump. The pelletizer resid pump was a gear pump capable of pumping up to 5 gpm. High temperature, moderate pressure seals provided a positive leakproof connection between the feed line and the centrifugal head while transferring the resid.
The pump was calibrated before each pelletization experiment. As the resid entered the centrifugal head, the centrifugal force discharged long, thin cylinders of the resid into the free space at the top of the pelletizer. As the resid traveled downwardly in the vapor space, the resid broke up into spherical pellets as the surface tension force overcame the combined viscous and inertial forces. The pellets fell spirally into the collection tray where a cooling water bath was maintained.
The experimental centrifugal head was housed in a metal chamber and the vapor inside the chamber was maintained close to the resid feed temperature using two kerosene-fired air heaters. The centrifugal head was heated close to the resid temperature using induction coil heaters. The metal chamber was heated to overcome the viscous force to form spherical pellets, and this also reduced the throw-away diameter and inhibited stringing of the resid. Experiments were performed with single and multiple orifices and pellets were produced successfully at high throughput. While operating with multiple orifices, the pellets did not agglomerate in the vapor space or while falling into the pellet collection tray.
Examples 1 and 2 illustrate the operation of the resid pelletization apparatus using a centrifugal extrusion device according to the principles of this invention and demonstrated the ability of this apparatus to successfully produce pellets. Resid properties and operating parameters are presented in Table 2 below:
TABLE 2
Property/Parameter
Example 1
Example 2
Resid Properties
R&B softening point, ° F.
265
292
Sulfur, wt %
1.7
4.1
Storage test to 150° F. with axial load
Passed
Passed
Friability test, fines, wt %
<2 wt %
<2 wt %
Heating value, net, Btu/lb
16,900
16,730
Pellet Size, mm
0.5 to 3
0.5 to 3
Operating Parameters
Centrifugal head diameter, inches
2.4
2.4
Total Number of Orifices
32
32
Number of orifices used
1
1 and 4
Orifice configuration
Triangular
Triangular
Orifice Diameter, inches
0.03125
0.03125
Throw-away diameter, ft
3.5 to 5
3 to 5 ft
Resid feed temperature, ° F.
500
535
RPM
900-1500
900-1500
Throughput per orifice, lbs/hr
195
100 | Disclosed are a method and apparatus for making substantially spherical, homogenous petroleum resid pellets having a size range between 0.1 and 10 mm, a penetration of essentially 0, a softening point temperature from about 200° to about 400° F., a residual water content of from 0.1 to 10 weight percent, and a sulfur content less than 10 weight percent. The process includes feeding the material in a molten state to a rotating prilling head to discharge the material into free space at an upper end of a pelletizing vessel having a diameter larger than a throw-away diameter of the discharged material, allowing the discharged material to break apart, form into substantially spherical liquid pellets, and fall downwardly into a liquid spray and/or bath to solidify the pellets. The apparatus has an upright pelletizing vessel with an upper prilling zone, a sphere-forming zone below the prilling zone, a cooling zone below the sphere-forming zone, a bath below the cooling zone, and a prilling head in the prilling zone rotatable along a vertical axis and having a plurality of discharge orifices for throwing molten material radially outwardly. A vertical height of the sphere-forming zone is sufficient to allow material discharged from the prilling head to form substantially spherical liquid pellets. Nozzles are provided for spraying water inwardly into the cooling zone to cool and at least partially solidify the liquid pellets to be collected in the bath. Also disclosed is pretreatment of a soft resid (softening point temperature below 200° F.) by air oxidation to produce a hard resid suitable for feed to the prilling head. | 1 |
BACKGROUND OF THE INVENTION
This invention relates to digital computers, and more particularly, it relates to digital computer systems in which a plurality of independent processors interact to perform respective activities within various tasks.
Conventionally, a data processing task is performed in its entirety by a single computer. That task, for example, may be the solving of a scientific problem, the calculation of a payroll, etc. But in any case, the speed at which the task is performed by the single computer depends directly upon the number of data bits that the computer can process in a single cycle and the speed of that cycle.
Thus, the computing power of a single computer conventionally is increased by either increasing the number of bits which the computer can operate on in a single cycle or by shortening the computer's cycle time. However, the extent to which the cycle time can be shortened is limited by the speed at which integrated circuits operate. And increasing the number of bits on which a computer can operate in a single cycle also causes the complexity of the computer's design and maintenance to increase.
Alternatively, the speed at which a data processing task is performed may be increased by providing a plurality of independent processors each of which performs one or more activities within the task. In such a multiprocessor system, the individual processors can be tailored to perform their respective activities which decreases the execution time of the overall task. Further, the individual processors of the system inherently make the system modular, which reduces the complexity of the system's design and maintenance.
Also, in the multiprocessor system, the various processors can perform activities for several unrelated tasks at the same time. This allows for more parallelism within the system, which further increases the system's computing power.
However, in the multiprocessor system, some means must be provided for coordinating the various activities that the processors perform. That is, a means must be provided for keeping the execution of activities within a task in the correct sequence. And a means must be provided for keeping many processors active at the same time. But this becomes very complicated as the number of processors, number of tasks, and number of activities within each task increases.
Accordingly, a primary object of the invention is to provide a controller for controlling access to a plurality of records that can be accessed and changed by several independent processors.
BRIEF SUMMARY OF THE INVENTION
In the present invention, a controller for controlling access to a plurality of records that can be accessed and changed by several independent processors comprises: a plurality of flip-flops corresponding in number to the plurality of records with each flip-flop representing a particular record; a means for receiving a programmable control word from any of the processors which identifies multiple records of which access is sought; a means for selecting in parallel and logically ANDing output signals from all of those flip-flops which correspond to said identified records; a means for sending a signal, if the ANDing operation yields a logical ONE, to the processor which sent the control word signaling that it may access and change the identified records; a means for setting in parallel via a single pulse all of those flip-flops which correspond to the identified records if the ANDing operation yields a logical ONE; and a means for storing the control word if the ANDing operation yields a logical ZERO.
BRIEF DESCRIPTION OF THE DRAWINGS
Various features and advantages of the invention are described in the Detailed Description in conjunction with the accompanying drawings wherein:
FIG. 1 illustrates a system in which sequences of activities in digital processors are synchronized according to the invention;
FIG. 2 illustrates an exemplary arrangement of the processor records and activity records in the shared memory of the FIG. 1 system;
FIGS. 3, 4, 5, and 6 illustrate examples of how the pointers in the processor records and activity records of the FIG. 1 system change in response to the execution of INTERPROCESSOR instructions;
FIG. 7 illustrates another system for synchronizing sequences of activities within digital processors according to the invention; and
FIGS. 8A and 8B illustrate the detailed logic of a file access controller in the FIG. 7 system.
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, a plurality of "n" independent digital processors are represented by several boxes labeled P 1 , P 2 , . . . P n . These processors may be of any programmable type; and they may be the same or different from each other. Suitably, processors P 1 through P n are of the type described in U.S. Pat. No. 4,346,438 entitled "Digital Computer Having Programmable Structure" by H. Potash et al and assigned to Burroughs Corporation, or of the type described in U.S. Pat. No. 4,327,355 entitled "Digital Device with Interconnect Matrix" by H. Potash et al and assigned to Burroughs Corporation.
Processors P 1 , P 2 , . . . P n are coupled to memories M 1 , M 2 , . . . M n respectively. These memories may be any digital type memory. For example, they may be static or dynamic type semiconductor memories; and they may be made of MOS or bipolar circuitry. Also, the storage capacity and operating speed of the memories may be the same or different from each other.
One portion of memory M 1 contains the data that processor P 1 operates on; while another portion of memory M 1 contains the intraprocessor activities that processor P 1 performs. As used herein, an intraprocessor activity is comprised of a program or set of programs which direct a processor to perform a particular task by using only the resources of that processor. Such resources include the processor's own internal hardware, the processor's memory, and any peripheral equipment such as disks, tapes, etc. (not shown) connected to the processor. In FIG. 1, the respective intraprocessor activities that processor P 1 performs are symbolically indicated as A 1 P 1 , A 2 P 1 , . . . , etc.
Similarly, a portion of memory M 2 contains the data that processor P 2 operates on; and another portion of memory M 2 contains the intraprocessor activities that processor P 2 performs. Those activities are indicated in FIG. 1 as A 1 P 2 , A 2 P 2 , . . . , etc. In like fashion, memory M n contains the data that processor P n operates on; and it contains the intraprocessor activities A 1 P n , A 2 P n , . . . that processor P n performs.
Each of the memories M 1 , M 2 , . . . M n also contains interprocessor instructions. They are an INTERPROCESSOR CALL, an INTERPROCESSOR RETURN, and an INTERPROCESSOR NEXT instruction. In general, these interprocessor instructions provide the means by which the processors P 1 , P 2 . . . P n communicate with one another. More specifically, they provide the means by which all of the intraprocessor activities A 1 P 1 , A 1 P 2 . . . A 1 P n , etc. are linked together and performed in an orderly synchronized sequence as is explained in much greater detail below.
Processors P 1 , P 2 , . . . P n are coupled via a single time-shared bus to an intelligent memory controller IMC; and controller IMC is coupled to a shared memory SM. Controller IMC preferably is a programmable computer of the type referenced above; and memory SM may be any type of read/write memory.
Memory SM contains one separate processor record for each of the processors; and each such record is herein indicated as PR i . Memory SM also contains a separate activity record for each of the intraprocessor activities in the processors; and each such record is indicated as AR x P i . Further, memory SM contains parameters that are shared and passed from one processor to another via the interprocessor instructions.
Included in each processor record PR i are flags which indicate whether processor P i is currently BUSY performing an activity or NOT BUSY. Processor record PR i also contains a CURRENT entry which points to the current intraprocessor activity that processor P i is performing if the processor is BUSY.
Processor record PR i further includes a PROCESSOR QUEUE HEAD entry (PQH), and a PROCESSOR QUEUE TAIL entry (PQT). These two entries respectively point to the head and tail of a queue of activity records for the different kinds of intraprocessor activities that processor P i is to perform. That is, a pointer to the same kind of activity is entered into the processor queue only once even though that activity may be called several times. Processor record PR i may also include other entries, as a matter of design choice, in addition to those described above.
Activity record AR x P i includes a set of flags indicating when the corresponding activity is DORMANT, or ACTIVE, or SUSPENDED. An activity is ACTIVE when a processor is actually being used to execute that activity. An activity remains ACTIVE but in a SUSPENDED state when it has executed partway to completion and then stopped while it awaits the results of another activity in another processor. Such results are requested and obtained via the INTERPROCESSOR INSTRUCTIONS. In all other cases, an activity is DORMANT.
Activity record AR x P i also includes a CALLER entry which is a pointer to the activity record of the activity which is first to call activity A x P i . Any subsequent callers of activity A x P i are kept track of by means of an ACTIVITY QUEUE TAIL entry (AQT) and ACTIVITY QUEUE HEAD entry (AQH) in the activity record.
Specifically, pointers to the subsequent callers of activity A x P i are placed in a queue of that activity. Entry AQH points to the activity record of the second caller of activity A x P i ; and entry AQT points to the activity record of the last caller of activity A x P i . Intermediate entries in either the activity queue or the processor queue are linked together by a NEXT IN QUEUE entry (NIQ) in the activity records of the various callers of an activity.
Activity record AR x P i also has a PARAMETER entry (PARAM) which contains a pointer to parameters that are passed between two activities via the INTERPROCESSOR INSTRUCTIONS. For example, when activity A x P i calls activity A y P j , then the PARAM entry of activity record AR x P i points to parameters in the shared memory SM on which activity A y P j is to operate. Conversely, when activity A y P j completes, then the PARAM entry in activity record AR x P i points to parameters in the shared memory that are being passed by activity A y P j to activity A x P i .
One example of a complete set of the processor records and activity records for a FIG. 1 system is illustrated in FIG. 2. In this example, there are eleven processor records PR 1 through PR 11 which respectively represent eleven physical processors P 1 through P n . Also in this example, the number of activities that each processor performs varies from processor to processor.
FIG. 2 shows that processor 1 performs five intraprocessor activities; and the above-described pointers for those activities are respectively in activity records AR 1 P 1 through AR 5 P 1 . In like manner, FIG. 2 shows that processor 2 performs eleven intraprocessor activities, processor 3 performs nine intraprocessor activities, processor 4 performs three intraprocessor activities, etc. Again, these activity records and processor records each have their own pointers that keep track of which activity is calling which; and resolve the order by which the various processors perform their respective intraprocessor activities.
Consider now the details of the operations that are performed by the controller IMC in response to the INTERPROCESSOR CALL instruction. TABLE 1 below lists those operations for the generalized case where activity A x P i in processor P i calls activity A y P j in processor P j .
TABLE 1______________________________________ (A.sub.x P.sub.i CALLS A.sub.y P.sub.j)______________________________________AR.sub.y P.sub.j PR.sub.j ACTION TAKEN______________________________________DORMANT NOT SET AR.sub.y P.sub.j ACTIVE BUSY AR.sub.x P.sub.i POINTER→AR.sub.y P.sub.j CALLER AR.sub.y P.sub.j POINTER→PR.sub.j CURRENT SET PR.sub.j BUSY NOTIFY P.sub.jDORMANT BUSY SET AR.sub.y P.sub.j ACTIVE AR.sub.x P.sub.i POINTER→AR.sub.y P.sub.j CALLER AR.sub.y P.sub.j POINTER→PR.sub.j QUEUEACTIVE O AR.sub.x P.sub.i POINTER→AR.sub.y P.sub.j QUEUEPR.sub.i QUEUE ACTION TAKENNOT EMPTY POP PR.sub.i QUEUE POPPED ENTRY→PR.sub.i CURRENT NOTIFY P.sub.i (AR.sub.x P.sub.i REMAINS ACTIVE)EMPTY SET PR.sub.i NOT BUSY O→PR.sub.i CURRENT (AR.sub.x P.sub.i REMAINS ACTIVE)______________________________________
If activity A y P j is DORMANT and processor P j is NOT BUSY, then controller IMC performs the following tasks. First it makes activity A y P j ACTIVE by setting the ACTIVE flag in activity record AR y P j . Then it loads a pointer to activity record AR x P i into the CALLER entry of activity record AR y P j . Also, a pointer to activity record AR y P j is loaded into the CURRENT entry of processor record PR j . Then the BUSY flag for processor record PR j is set, and a message is sent to processor P j which notifies it to start performing activity A y P j .
If, however, activity A y P j is DORMANT and processor P j is BUSY at the time of the INTERPROCESSOR CALL, then controller IMC operates as follows. First it sets the ACTIVE flag in activity record AR y P j . Then it loads a pointer to activity record AR x P i into the CALLER location of activity record AR y P j . Then it loads a pointer to activity record AR y P j into the queue of processor record PR j . This latter operation involves loading a pointer to activity record AR y P j into the NEXT IN QUEUE entry of the activity record that is pointed to by the PROCESSOR QUEUE TAIL of processor record PR j ; and then changing the PROCESSOR QUEUE TAIL entry of processor record PR j such that it also points to activity record AR y P j .
Finally, if activity A y P j is ACTIVE at the time of the INTERPROCESSOR CALL, then the intelligent memory controller loads a pointer to activity record AR x P j into the queue of activity record AR y P j . This involves loading a pointer to activity record AR x P i into the NEXT IN QUEUE entry of the activity record that is pointed to by the ACTIVITY QUEUE TAIL of activity record AR y P j ; and then changing the ACTIVITY QUEUE TAIL in activity record AR y P j to point to activity record AR x P i .
Note that the above operations only affect the CALLED activity record and CALLED processor record. But in addition, various operations must also be performed on the CALLING activity record and CALLING processor record. These operations are as follows.
If the queue in the CALLING processor record PR i is NOT EMPTY, then one entry is removed from that queue and loaded into the CURRENT entry of processor record PR i . This unloading operation involves moving the PROCESSOR QUEUE HEAD entry of processor record PR i into the CURRENT entry of processor record PR i ; and then the NEXT IN QUEUE entry from the activity record that is pointed to by the PROCESSOR QUEUE HEAD in processor record PR i is loaded into the PROCESSOR QUEUE HEAD of processor record PR i . Also, a message is sent by the controller IMC to processor P i which notifies that processor of the new activity that is pointed to by the CURRENT entry in the processor record PR i .
If, on the other hand, the queue in processor record PR i is EMPTY, then the flags in that processor record are set to indicate that processor P i is NOT BUSY. Also, under those conditions, the CURRENT entry in processor record PR i is set to a null value. Note further that in both this and the above case, the ACTIVE flag in the calling activity record AR x P i remains set, even though the calling activity is in a suspended state.
Next, consider the operations that are performed by the controller IMC in response to an INTERPROCESSOR RETURN instruction from one of the processors. Specifically, consider the case where activity A y P j in processor P j RETURNS to activity A x P i in processor P i . These operations are listed in TABLE 2 below.
If the queue of activity record AR y P j is NOT EMPTY when the RETURN occurs, then the controller IMC performs the following operations. Firstly, one entry is removed from the queue of activity record AR y P j . This is achieved by moving the pointer in the ACTIVITY QUEUE HEAD of activity record AR y P j into the CALLER location of activity record AR y P j ; and moving the NEXT IN QUEUE entry of the activity record that is pointed to by the ACTIVITY QUEUE HEAD of activity record AR y P j into the ACTIVITY QUEUE HEAD of activity record AR y P j .
TABLE 2______________________________________(A.sub.y P.sub.j RETURNS TO A.sub.x P.sub.i)AR.sub.y P.sub.j PR.sub.j ACTION TAKEN______________________________________QUEUE POP AR.sub.y P.sub.j QUEUENOT NOTIFY P.sub.j TO RE-EXECUTE AR.sub.y P.sub.jEMPTYQUEUE QUEUE SET AR.sub.y P.sub.j DORMANTEMPTY NOT POP PR.sub.j QUEUE EMPTY POPPED ENTRY→PR.sub.j CURRENT NOTIFY P.sub.jQUEUE QUEUE SET PR.sub.j NOT BUSYEMPTY EMPTY O→PR.sub.j CURRENT______________________________________PR.sub.i ACTION TAKEN______________________________________BUSY AR.sub.x P.sub.i POINTER→PR.sub.i QUEUENOT BUSY AR.sub.x P.sub.i POINTER→PR.sub.i CURRENT NOTIFY P.sub.i______________________________________
Thereafter, a message is sent to processor P j to re-execute activity A y P j for the new caller of that activity.
On the other hand, if the queue of activity A y P j is EMPTY but the queue of processor P j is NOT EMPTY when the RETURN instruction is sent to the controller IMC, then that controller performs the following operations. Firstly, the flags in activity record AR y P j are changed to indicate a DORMANT state. Then one entry is removed from the queue of the processor record PR j and the CURRENT entry in that processor record is updated with that entry that is removed from the queue. Then a message is sent to processor P j which informs the processor of the new activity record that is being pointed to by the CURRENT entry in processor record PR j .
Finally, if the queue of activity record AR y P j and the queue of processor record PR j are both EMPTY when the RETURN instruction is sent to the controller IMC, then there are no other activities for processor P j to currently perform. Consequently, the flags in processor record PR j are set to indicate that processor P j is NOT BUSY; and the CURRENT entry in processor record PR j is set to a null state.
All of the above operations for the RETURN instruction are performed on the CALLED activity record AR y P j and CALLED processor record PR j . In addition, the following operations are performed in response to the RETURN instruction on the CALLING activity record AR x P i and CALLING processor record PR i .
If the flags in the CALLING processor record PR i indicate that processor P i is BUSY, then the intelligent memory controller loads a pointer to activity record AR x P i into the queue of processor record PR i . This is performed, when the queue of processor record PR i is not empty, by loading the pointer to activity record AR x P i into the NEXT IN QUEUE entry of the activity record that is pointed to by the PROCESSOR QUEUE TAIL in processor record PR i ; and by changing the PROCESSOR QUEUE TAIL entry to also point to activity record AR x P i . And it is achieved, when the queue of processor record PR i is empty, by loading the pointer to activity record AR x P i into the PROCESSOR QUEUE HEAD and PROCESSOR QUEUE TAIL of processor record PR i .
If, however, processor P i is NOT BUSY, then the pointer to activity record AR x P i is loaded into the CURRENT entry of processor record PR i ; and the flags of processor record PR i are set to indicate that processor P i is BUSY. Then a message is sent to processor P i to notify the processor of the new activity that it is to perform as indicated by the new CURRENT entry in processor record PR i .
Consider now the operations that are performed by the controller IMC in response to an INTERPROCESSOR NEXT instruction from one of the processors. Specifically, consider the actions that are taken in the generalized case where activity A y P j in processor P j performs a NEXT instruction to activity A z P k in processor P k . These operations are listed in TABLE 3 below.
Those operations which are performed on activity record AR y P j and processor record PR j in response to the NEXT instruction are the same as the operations which are performed on activity record AR y P j and processor record PR j in response to the RETURN instruction as described above. But the operations that are performed in response to the NEXT instruction on activity record AR z P k and processor record PR k are as follows.
If activity A z P k is ACTIVE, then a pointer to activity record AR x P i gets loaded into the activity queue of activity record AR z P k . This is achieved by moving the CALLER entry of activity record AR y P k into the activity queue of activity record AR z .
If, however, activity A z P k is DORMANT and processor P k is BUSY at the time the NEXT instruction is sent to controller IMC, then that controller performs the following operations. First, a pointer to activity record AR z P k is loaded into the queue of processor record PR k . Then, the CALLER entry of activity record AR y P j (which is a pointer to
TABLE 3______________________________________ (A.sub.y P.sub.j CALLED BY A.sub.x P.sub.i PERFORMS NEXT A.sub.z______________________________________P.sub.k)AR.sub.y P.sub.j PR.sub.j ACTION TAKEN______________________________________QUEUE POP AR.sub.y P.sub.j QUEUENOT NOTIFY P.sub.j TO RE-EXECUTE AR.sub.y P.sub.jEMPTYQUEUE QUEUE SET AR.sub.y P.sub.j DORMANTEMPTY NOT POP PR.sub.j QUEUE EMPTY POPPED ENTRY→PR.sub.j CURRENT NOTIFY P.sub.jQUEUE QUEUE SET PR.sub.j NOT BUSYEMPTY EMPTY O→PR.sub.j CURRENTAR.sub.z P.sub.k PR.sub.k ACTION TAKENACTIVE O AR.sub.x P.sub.i POINTER→AR.sub.z P.sub.k QUEUEDORMANT BUSY AR.sub.z P.sub.k POINTER→PR.sub.k QUEUE AR.sub.x P.sub.i POINTER→AR.sub.z P.sub.k CALLER SET AR.sub.z P.sub.k ACTIVEDORMANT NOT AR.sub.z P.sub.k POINTER→PR.sub.k CURRENT BUSY AR.sub.x P.sub.i POINTER→AR.sub.z P.sub.k CALLER SET AR.sub.z P.sub.k ACTIVE______________________________________
activity record AR x P i ) is moved to the CALLER entry of activity record AR z P k . Then, the flags in activity record AR z P k are set to an ACTIVE state.
On the other hand, if processor P k is NOT BUSY at the time that the NEXT instruction is sent to the intelligent memory controller, then that controller performs the following operations. The pointer to activity record AR z P k is loaded into the CURRENT entry of processor record PR k . Also, the CALLER entry of activity record AR y P j (which is a pointer to activity record AR x P i ) is loaded into the CALLER entry of activity record AR z P k . Then the flags in activity record AR z P k are set to an ACTIVE state.
Reference should now be made to FIG. 3. It illustrates an exemplary sequence of the above-described changes that occur to the processor records and activity records during a CALL and corresponding RETURN operation. That sequence occurs during time instants t 1 through t 5 ; and TABLE 4 below outlines the events which occur at each time instant.
TABLE 4______________________________________TIME ACTION TAKEN______________________________________t.sub.1 P.sub.x performing A.sub.b P.sub.x, P.sub.y performing A.sub.d P.sub.yt.sub.2 P.sub.x CALLS A.sub.c P.sub.y, suspends A.sub.b P.sub.x, & starts A.sub.a P.sub.xt3 P.sub.y completes A.sub.d P.sub.y and starts A.sub.c P.sub.yt4 P.sub.y completes A.sub.c P.sub.y and RETURNS to A.sub.b P.sub.xt5 P.sub.x completes A.sub.a P.sub.x and RETURNS to______________________________________ A.sub.b P.sub.x
In this example, there are two processors P x and P y ; and they have processor records PR x and PR y respectively. Initially, processor P x is BUSY performing an activity A b P x which has an activity record AR b P x . Also, another activity A a P x which has an activity record AR a P x is waiting in the PR x processor queue to be performed; and Processor P y is BUSY performing an activity A c P y . These initial conditions are indicated in FIG. 3 by the pointers having reference numeral 1.
Specifically, the CURRENT entry with reference numeral 1 in processor record PR x points to activity record AR b P x to indicate that processor P x is initially performing activity A b P x . Also, the PROCESSOR QUEUE HEAD entry and PROCESSOR QUEUE TAIL entry with reference numeral 1 in processor record PR x point to activity record AR a P x to indicate that activity A a P x is initially in the queue of processor record PR x .
Further, the CURRENT entry with reference numeral 1 of processor record PR y points to activity record AR d P y to indicate that initially processor P y is performing activity A d P y . And, the PROCESSOR QUEUE HEAD entry with reference numeral 1 of processor record PR y has a null value to indicate that no other activities are waiting to be performed on processor P y .
Subsequently, as indicated by the pointers in the records having reference numeral 2, activity A b P x CALLS activity A c P y . As a result, the CALLER entry in activity record AR c P y is written such that it points to activity record AR b P x ; and the PROCESSOR QUEUE HEAD and PROCESSOR QUEUE TAIL entries in processor record PR y are written such that they point to activity record AR c P y .
Also, since activity A b P x was a CALLER, processor P x suspends execution of that activity and begins execution of another activity which it gets from its queue. Consequently, the CURRENT entry in processor record PR x is written to point to activity record AR a P x ; and the PROCESSOR QUEUE HEAD entry of processor record PR x is written to a null value.
Subsequently, as indicated by the record entries having reference numeral 3, processor P y completes the execution of activity A d P y ; and thus it starts the execution of another activity in its queue. Thus, the CURRENT entry in processor record PR y is written to point to activity record AR c P y and the PROCESSOR QUEUE HEAD entry of processor record PR y is written to a null value.
Thereafter, as indicated by the record entries having reference numeral 4, processor P y completes the execution of activity A c P y . Thus, the activity that CALLED activity A c P y can resume execution; and so a pointer to activity record AR b P x is loaded into the PROCESSOR QUEUE HEAD and PROCESSOR QUEUE TAIL entries of processor record PR x . Also, processor P y is free to perform another activity; but since its processor queue is EMPTY, the CURRENT pointer of processor record PR y is written to a null value.
Processor P x continues with the execution of activity A a P x until that activity completes or calls another activity. That occurs at time t 5 . Then, processor P x resumes execution of activity A b P x since activity record AR b P x is pointed to by the processor queue of processor record PR x .
Referring now to FIGS. 4 and 5, another example of a sequence of the changes that occur to the processor records and activity records during several CALL and RETURN operations will be described. In this example, an activity A 1 P x which processor P x performs is CALLED three times and another activity A 2 P x which processor P x also performs is CALLED two times.
All of this calling occurs while processor P x is busy performing another activity; so the queues in processor records PR x and activity records AR 1 P x and AR 2 P x get loaded while the calling occurs. Subsequently, processor P x finishes the task that it was performing; and then it performs the activities which are pointed to in the queues of the processor and activity records. TABLE 5 below lists the sequence by which the various events occur.
TABLE 5______________________________________TIME ACTION TAKEN______________________________________t.sub.1 P.sub.x performing some activityt.sub.2 A.sub.a P.sub.1 CALLS A.sub.1 P.sub.xt.sub.3 A.sub.b P.sub.2 CALLS A.sub.2 P.sub.xt.sub.4 A.sub.c P.sub.3 CALLS A.sub.1 P.sub.xt.sub.5 A.sub.d P.sub.4 CALLS A.sub.2 P.sub.xt.sub.6 A.sub.e P.sub.5 CALLS A.sub.1 P.sub.xt.sub.7 P.sub.x RETURNS to A.sub.1 P.sub.x for A.sub.a P.sub.1t.sub.8 P.sub.x RETURNS to A.sub.1 P.sub.x for A.sub.c P.sub.3t.sub.9 P.sub.x RETURNS to A.sub.1 P.sub.x for A.sub.e P.sub.5.sup. t.sub.10 P.sub.x RETURNS to A.sub.2 P.sub.x for A.sub.b P.sub.2.sup. t.sub.11 P.sub.x RETURNS to A.sub.2 P.sub.x for A.sub.d P.sub.4______________________________________
FIG. 3 illustrates the sequence by which the processor and activity record queues get loaded; while FIG. 4 illustrates the sequence by which the queues get unloaded. In both of these figures, the pointers having reference numerals 1 through 11 respectively indicate the various entries in the processor and activity records at sequential time instants which correspond to those numbers.
Inspection of FIG. 4 shows that during time instants t 1 -t 6 , the CURRENT entry of processor record PR x is pointing to an activity record which processor P x is currently performing. But at time instant t 2 , an activity A a P 1 in processor P 1 CALLS activity A 1 P x . As a result, the CALLER entry of activity record AR 1 P x is written such that it points to activity record AR a P 1 ; and the PROCESSOR QUEUE HEAD and PROCESSOR QUEUE TAIL entries of processor record PR x are written such that they point to activity record AR 1 P x .
Thereafter, at time instant t 3 , an activity A b P 2 in processor P 2 CALLS activity A 2 P x in processor P x . As a result of this CALL, the CALLER entry in activity record AR 2 P x is written to point to activity record AR b P 2 . Also, the PROCESSOR QUEUE TAIL entry of processor record PR x is changed to point to activity record AR 2 P x ; and the NEXT IN QUEUE entry of activity record AR 1 P x is written to point to activity record AR 2 P x .
Subsequently, at time instant t 4 , an activity A c P 3 in processor P 3 CALLS activity A 1 P x . This CALL of activity A 1 P x does not reload activity record AR 1 P x into the queue of processor record PR x ; but instead, a pointer to activity record AR c P 3 is written into the activity queue of activity record AR 1 P x . This is achieved by writing the ACTIVITY QUEUE HEAD and ACTIVITY QUEUE TAIL entries of activity record AR 1 P x such that they point to activity record AR c P 3 .
Next, at time instant t 5 , an activity A d P 4 in a processor P 4 CALLS activity A 2 P x . Again, since the activity record AR 2 P x is already in the processor queue of processor record PR x , a pointer to activity record AR d P 4 is simply loaded into the activity queue of activity record AR 2 P x . This is achieved by writing the ACTIVITY QUEUE HEAD and ACTIVITY QUEUE TAIL entries of activity record AR 2 P x such that they point to activity record AR d P 4 .
Then, at time instant t 6 , an activity A e P 5 in a processor P 5 CALLS activity A 1 P x . As a result, activity record AR e P 5 is loaded into the activity queue of activity record AR 1 P x . This is achieved by changing the ACTIVITY QUEUE TAIL entry of activity record AR 1 P x such that it points to activity record AR e P 5 ; and by writing the NEXT IN QUEUE entry of activity record AR c P 3 such that it also points to activity record AR e P 5 .
Turning now to FIG. 5, the unloading of the queues in processor record PR x , activity record AR 1 P x , and AR 2 P x will be described. In FIG. 5, those pointers having reference numeral 6 are the same as the pointers having reference numeral 6 in FIG. 4.
At time instant t 7 , processor P x completes the activity which it was working on at time instants t 1 through t 6 . Thus it performs an INTERPROCESSOR RETURN instruction. In response thereto, the controller IMC removes an activity record from the queue in processor record PR x and notifies processor record PR x of that removed activity. This removal operation is achieved via controller IMC by moving the PROCESSOR QUEUE HEAD entry in processor record PR x to the CURRENT entry in that processor record; and by moving the NEXT IN QUEUE entry of activity record AR 1 P x to the PROCESSOR QUEUE HEAD entry of processor record PR x .
Thereafter, at time instant t 8 , processor P x completes activity A 1 P x . Thus it performs another INTERPROCESSOR RETURN instruction. In response to that RETURN instruction, controller IMC removes one activity record from the activity queue of activity record AR 1 P x . This it achieves by moving the ACTIVITY QUEUE HEAD entry in activity record AR 1 P x to the CALLER entry of that record; and by moving the NEXT IN QUEUE entry of activity record AR c P 3 into the ACTIVITY QUEUE HEAD entry of activity record AR 1 P x . Then processor P x is notified that it should re-execute activity A 1 P x for the second caller of that activity.
At time instant t 9 , processor P x again completes the execution of activity A 1 P x . Thus, it again executes an INTERPROCESSOR RETURN instruction. In response thereto, the controller IMC removes another activity record from the activity queue of activity record AR 1 P x . This it achieves by moving, the ACTIVITY QUEUE HEAD entry of activity record AR 1 P x into the CALLER entry of that activity and by setting the ACTIVITY QUEUE HEAD entry of activity record AR 1 P x to a null value. Then, controller IMC informs processor P x to re-execute activity A 1 P x for the third caller of that activity.
Thereafter, at time instant t 10 , processor P x completes the execution of activity A 1 P x ; and so it again executes an INTERPROCESSOR RETURN instruction. In response thereto, controller IMC removes another activity record from the processor queue of processor record PR x ; and it informs processor P x of the new activity that it is to perform. This removal operation is achieved by moving the PROCESSOR QUEUE HEAD entry of processor record PR x into the CURRENT entry of that record and by changing the PROCESSOR QUEUE HEAD entry in processor record PR x to a null value.
Next, at time instant t 11 , processor P x completes the execution of activity A 2 P x . Thus it again executes an INTERPROCESSOR RETURN instruction. In response thereto, controller IMC removes an entry from the activity queue of activity record AR 2 P x and informs processor P x to re-execute activity A 2 P x for the second caller of that activity. This removal operation is achieved by moving the ACTIVITY QUEUE HEAD entry of activity record AR 2 P x to the CALLER entry of that activity and by setting the ACTIVITY QUEUE HEAD entry of activity record AR 2 P x to a null value.
After processor P x completes the execution of activity A 2 P x , it will again execute an INTERPROCESSOR RETURN instruction. At that point, there are no other activities for processor P x to perform; and so controller IMC merely resets the BUSY flag in processor record PR x and sets the CURRENT entry of that record to a null value.
From the above sequence of operations, it can be seen that the order in which processor P x performed activities A 1 P x and A 2 P x was entirely different than the order in which those activities were called. Specifically, the activities were called in the following order: A 1 P x , A 2 P x , A 1 P x , A 2 P x , and A 1 P x ; but the order in which the activities were performed was: A 1 P x , A 1 P x , A 1 P x , A 2 P x , and A 2 P x .
In other words, activity A 1 P x was performed once for every one of its callers; and then activity A 2 P x was performed once for every one of its callers. And this occurs regardless of the order in which those activities are called. Such re-ordering of the activities is important because it minimizes the number of times that a processor switches from performing one activity to another.
Each time a switch occurs, the code for the new activity must be read into the memory of the processor which is to perform the activity. Also, space must be re-allocated in the memory for data on which the activity performs. These resource-allocating operations are time-consuming; and thus they detract from the overall performance of the system.
Reference should now be made to FIG. 6 which illustrates the operation of the INTERPROCESSOR NEXT instruction. In this figure, as in the previous FIGS. 3-5, the pointers having reference numerals 1 through 9 indicate respective entries in the activity records and processor records at time instants which correspond to those reference numerals.
TABLE 6 below lists the sequence of events that occur in FIG. 6 in outline form. This outline shows a sequence in which an activity A a P 1 calls another activity A b P 2 ; then activity A b P 2 executes a NEXT instruction to an activity A c P 3 ; then activity A c P 3 executes a NEXT instruction to an activity A d P 4 ; then activity A d P 4 returns directly to A a P 1 without reentering activities A b P 2 or A c P 3 .
TABLE 6______________________________________TIME ACTION TAKEN______________________________________t.sub.1 P.sub.1 executes A.sub.a P.sub.1t.sub.2 P.sub.1 CALLS A.sub.b P.sub.2, suspends A.sub.a P.sub.1t.sub.3 P.sub.2 begins A.sub.b P.sub.2 for A.sub.a P.sub.1t.sub.4 P.sub.2 continues to execute A.sub.b P.sub.2 for A.sub.a P.sub.1 while A.sub.x P.sub.4 CALLS A.sub.b P.sub.2t.sub.5 P.sub.2 executes a NEXT from A.sub.b P.sub.2 to A.sub.c P.sub.3 with A.sub.a P.sub.1 as CALLERt.sub.6 P.sub.3 executes A.sub.c P.sub.3 for A.sub.a P.sub.1t.sub.7 P.sub.3 executes a NEXT from A.sub.c P.sub.3 to A.sub.d P.sub.4 with A.sub.a P.sub.1 as CALLERt.sub.8 P.sub.4 executes A.sub.d P.sub.4 for A.sub.c P.sub.1 and RETURNS to A.sub.a P.sub.1t.sub.9 P.sub.1 continues execution of A.sub.a P.sub.1______________________________________
Inspection of FIG. 6 shows that at time t 1 , processor P 1 is executing an activity A a P 1 . That is because at time t 1 , the CURRENT entry in processor record PR 1 is pointing to activity record AR a P 1 .
Next, at time t 2 , activity A a P 1 SUSPENDS its execution by CALLING activity A b P 2 in processor P 2 . As a result, the CALLER entry in activity record AR b P 2 is written by controller IMC such that it points to activity record AR a P 1 . Also, since processor record PR 2 indicates that processor P 2 is currently busy performing another activity at time instant t 2 , the PROCESSOR QUEUE HEAD and PROCESSOR QUEUE TAIL entries of processor record PR 2 are written by controller IMC to point to activity record AR b P 2 .
Subsequently, at time t 3 , processor P 2 completes the execution of its current activity by performing an INTERPROCESSOR RETURN instruction. As a result, controller IMC moves the PROCESSOR QUEUE HEAD entry of processor record PR 2 to the CURRENT entry of that record; and so the execution of activity A b P 2 begins.
Subsequently, at time t 4 , another activity A x P y CALLS activity A b P 2 . Accordingly, since activity A b P 2 is in an ACTIVE state, a pointer to activity record AR x P y is written by controller IMC into the activity queue of activity record AR b P 2 .
Next, at time t 5 , activity A b P 2 performs an INTERPROCESSOR NEXT instruction to activity A c P 3 . As a result, controller IMC moves the CALLER entry of activity record AR b P 2 to the CALLER entry of activity record AR c P 3 . Thus, the pointers in activity record AR c P 3 are exactly as if activity A c P 3 had been called directly by activity A a P 1 .
As a result of the above moving of the CALLER entry, activity A b P 2 will not receive any parameters from activity A c P 3 . Instead, those parameters will be passed directly to activity A a P 1 . Thus, upon execution of the INTERPROCESSOR NEXT instruction, activity A b P 2 is free to be re-executed by additional callers of that activity. Accordingly, at time t 5 , controller IMC moves the ACTIVITY QUEUE HEAD entry of activity record AR b P 2 into the CALLER entry of that activity record; and it notifies processor P 2 to re-execute activity A b P 2 for its new caller.
At time t 6 , processor P 3 completes the execution of the activity that it was previously executing; and so it performs an INTERPROCESSOR RETURN instruction. As a result, controller IMC moves the pointer to activity record AR c P 3 from the PROCESSOR QUEUE HEAD entry to the CURRENT entry of processor record PR 3 . Processor P 3 then begins execution of activity A c P 3 .
Upon completion of activity A c P 3 at time t 7 , processor P 3 has the option to perform either an INTERPROCESSOR RETURN instruction or another INTERPROCESSOR NEXT instruction. In FIG. 6, an INTERPROCESSOR NEXT instruction is performed to activity A d P 4 . As a result, controller IMC moves the CALLER entry of activity record AR c P 3 to the CALLER entry of activity record AR d P 4 . Also, since processor P 4 is not busy, the CURRENT entry of processor record PR 4 is loaded by controller IMC with a pointer to activity record AR d P 4 ; and processor P 4 is notified to begin execution of activity A d P 4 .
At time t 8 , processor P 4 completes execution of activity A d P 4 . Thus, processor P 4 has the option of performing either an INTERPROCESSOR RETURN instruction or an INTERPROCESSOR NEXT instruction. In FIG. 6, processor P 4 performs an INTERPROCESSOR RETURN instruction.
Due to the INTERPROCESSOR RETURN, controller IMC loads the CALLER entry of activity record AR d P 4 into the processor queue of processor record PR 1 . Thereafter, at time t 9 , processor P 1 completes the execution of the activity that it was previously performing; and it resumes the execution of activity A a P 1 which it had previously suspended back at time t 2 .
This resumption of the execution of activity A a P 1 is possible since the parameters which that activity was waiting for from the CALLED activity A a P 2 were made available at time t 8 . But from the above, it is evident that those parameters did not merely come from the CALLED activity A b P 2 . Instead, they were the result of the sequential execution of three activities A b P 2 , A c P 3 , and A d P 4 .
But all of this sequential execution was completely hidden from activity A a P 1 due to the operation of the INTERPROCESSOR NEXT instruction. Consequently, the linking of activity A a P 1 to the other activities A c P 3 and A d P 4 was greatly simplified. Further, since activities A b P 2 and A c P 3 did not have to be re-executed as parameters where passed from activity A d P 4 to activity A a P 1 , that parameter passing occurred very quickly.
Reference should now be made to FIG. 7 which illustrates another system in which the plurality of processors P 1 , P 2 , . . . P n access and change multiple processor records, activity records, and parameters in a shared memory SM. This system differs primarily from the above-described FIG. 1 system in that it includes a file access controller 20 which authorizes the processors to access and change the records directly by conventional memory read and memory write commands.
That is, the records in the FIG. 7 system are stored in a conventional memory; they are accessed through a conventional nonintelligent memory controller MC; and the processors of the FIG. 7 system execute the INTERPROCESSOR instructions by sending sequences of one-word memory read and memory write commands directly to a nonintelligent memory controller MC. But before any processor sends such commands to the nonintelligent memory controller to read or write the records in the shared memory SM, it must receive authorization to do so from the file access controller 20.
FIG. 8 illustrates the details of one preferred embodiment of the file access controller 20. It includes a plurality of "n" flip-flops 21-1 through 21-n. In one embodiment, each flip-flop corresponds to one record in the shared memory SM. That is, each flip-flop corresponds to one processor record or one activity record. Alternatively, as a design choice, each flip-flop corresponds to one processor record and all of the corresponding activity records for that one processor record.
Initially, all of the flip-flops are reset. Then, before a processor is permitted to access any record, it must first interrogate the flip-flops to determine whether those which correspond to the records that it wants to access are presently reset. To that end, the requesting processor sends a message over the bus to a module 22 within the controller. Suitably, module 22 is a microprocessor.
That message which is sent to module 22 identifies the requesting processor; and it also identifies all of the records of which access is sought. For example, four processor records PR a , PR b , PR c , and PR d and all of the corresponding activity records may be identified by four encoded fields F a , F b , F c , and F d in the message.
Upon receiving the message, module 22 passes it over an internal bus 23 to a register 24. From there, fields F a , F b , F c , and F d are sent to the control input terminals of multiplexers 25a, 25b, 25c, and 25d respectively. Each multiplexer also has its data input terminals coupled to the Q outputs of all of the flip-flops 21-1 through 21-n.
Thus, field F a of register 24 causes the Q output of the one flip-flops which corresponds to field F a to be gated to the output of multiplexer 25a. Similarly, field F b of register 24 causes the Q output of the one flip-flop which corresponds to that field to be gated to the output of multiplexer 25b; etc. All of those Q outputs are then ANDed together by an AND gate 26; and the result is sent back to module 22 where it is sensed.
If the signal from AND gate 26 is a logic ONE, then module 22 sends a message over the bus authorizing the requesting processor to change the contents of the identified records. Internal bus 23 provides a means for sensing the requesting processor's identification so this message can be sent to it.
Also, if the signal from AND gate 26 is a ONE, module 22 sends a single clock pulse to all of the flip-flops 21-1 through 21-n. Those flip-flops are JK flip-flops; and which of them have an active signal on their J input is controlled by the F a , F b , F c , and F d fields in register 24. Thus, those flip-flops that correspond to the fields F a , F b , F c , and F d are all set in response to the single clock pulse.
More specifically, the F a , F b , F c , and F d fields in register 24 are sent to decoders 27a, 27b, 27c, and 27d respectively. Each of those decoders generates multiple output signals; but only one of those signals goes high at a time. That output signal which goes high corresponds to the code which the decoder receives from register 24.
In other words, the first output of decoder 27a goes high when field F a in register 14 equals a binary one; the second output of decoder 27a goes high when field F a in register 24 is a binary two; etc.
Also, the first output of decoders 27a, 27b, 27c, and 27d are all connected together in a WIRED-OR fashion. Thus, if any of the fields F a , F b , F c , or F d in register 24 equal a binary one, it will cause flip-flop 21-1 to be set. Similarly, the second output of decoders 27a, 27b, 27c, and 27d are connected together in a WIRED-OR fashion; etc.
Suppose now that module 22 receives a request from a processor to access various records as specified by fields F 1 through F 4 ; but the output of gate 26 is a ZERO which indicates that at least one of the corresponding flip-flops is set. In that case, module 22 loads the contents of register 24 into a first-in-first-out (FIFO) queue 28; and it adds one to a counter which is internal to module 22.
Next, suppose that one of the processors which previously was granted authorization to interrogate some records has completed its task. In that case, the processor must send module 22 a message indicating which records it has finished interrogating. Preferably, those records are identified in the message by multiple encoded fields.
That message is then sent by module 22 to a register 29. From there, the fields which contain the numbers of the records that were interrogated are sent to respective decoders. For example, four decoders 30a, 30b, 30c, and 30d are provided if the message in register 29 contains four encoded fields F a ', F b ', F c ', and F d '.
Decoders 30a through 30d all have their first outputs connected together in a WIRED-OR fashion; and they also connect to the K input of flip-flop 21-1. Thus, if any of the four fields in register 29 contains a binary one, flip-flop 21-1 will be reset when all of the flip flops are clocked.
Similarly, the second output of decoders 30a-30d are all connected together; and they are connected to the K input of flip-flop 20-2; etc. Thus, to reset the flip-flops which correspond to the records that were interrogated, module 22 merely clocks all of the flip-flops with a single pulse after it loads register 29.
Then module 22 examines its internal counter to determine how many entries are in the FIFO 28. If the count is not zero, module 22 moves the queue entries one at a time into register 24. After each such move, it examines the output of AND gate 26 to determine if it is in a ONE state.
If AND gate 26 is in a ONE state, then module 22 reads the requester portion of register 24 onto bus 23 and sends that requester a message indicating that it may now modify the records it requested. Also, all of the flip-flops 21-1 through 21-n are clocked by module 22 with a single pulse which sets them as directed by the outputs of decoders 27a through 27d. Further, the counter that is internal to module 22 is decremented by one.
Conversely, if the output of AND gate 26 is in a ZERO state, then module 22 merely reloads the contents of register 24 back into FIFO 28.
In FIG. 8, a set of six dashed lines represent respective conductors on which respective control signals are sent by module 22 to cause the above-described operations to occur. Specifically, a clock pulse is sent on conductor A to load a word into FIFO 28; and a clock pulse is sent on conductor B to unload a word from FIFO 28.
Also, a control signal is sent on conductor E to select the input data to register 24 to be from FIFO 28 or bus 23; and a clock pulse is sent on conductor F to load the selected input data into register 24. Further, a clock pulse is sent on conductor L to clock the flip-flops 21-1 through 21-n; and a clock pulse is sent on conductor M to load register 29.
One feature of the above-described file access controller 20 is that it enables several of the processors P 1 , P 2 , . . . P n to access and change various records in the shared memory at the same time. The only restriction on this is that no two processors can change the same record. Thus, for example, processor P 1 could be changing records 1, 15, 30 and 56, while processor P 2 is changing records 2, 12, 31 and 40, while processor P 3 is changing records 3, 11, 20 and 31.
Another feature of the FIG. 7 system is its flexibility. Once a processor obtains authorization from the file access controller 20 to interrogate and change particular records, it can do so by any sequence of memory read and memory write commands. Therefore, records may be first read; and then the processor may CALL one activity or another based on contents of the records that it read. This implements a CONDITIONAL INTERPROCESSOR CALL instruction.
As one example of the usefulness of a CONDITIONAL INTERPROCESSOR CALL instruction, suppose that two processors perform the same activities. Both processors, for example, may perform high-speed floating point mathematical activities. In that case, by performing a CONDITIONAL INTERPROCESSOR CALL instruction, the caller can first examine the activity records of the two processors that perform the floating point activities; and then it can CALL an activity in one processor or the other depending upon which processor was not presently busy.
Another feature of the FIG. 7 system is the speed at which a processor can acquire access to the records in the shared memory SM. To send a control word to the file access controller 20 over the bus takes one cycle; to pass that message to register 24 takes a second cycle; to wait for the test condition from AND gate 26 to stabilize takes a third cycle; and to send a message back to the requesting processor authorizing it to access the requested records based on AND gate 26 plus send a clock pulse to set the corresponding flip-flops 21-1 through 21-n takes a fourth cycle. Thus, with a cycle time of 100 nanoseconds, for example, access to the records is acquired in only 400 nanoseconds.
Various embodiments of the invention have now been described in detail. In addition, however, many changes and modifications can be made to these details without departing from the nature and spirit of the invention. Accordingly, it is to be understood that the invention is not limited to said details but is defined by the appended claims. | A controller for controlling access to a plurality of records that can be accessed and changed by several independent processors comprises: a plurality of flip-flops corresponding in number to the plurality of records with each flip-flop representing a particular record; a circuit for receiving a programmable control word from any of the processors which identifies multiple records of which access is sought; a circuit for selecting in parallel and logically ANDing output signals from all of those flip-flops which correspond to the identified records; a circuit for sending a signal, if the ANDing operation yields a logical ONE, to the processor which sent the control word signaling that it may access and change the identified records; a circuit for setting in parallel via a single pulse all of those flip-flops which correspond to the identified records if the ANDing operation yields a logical ONE; and a circuit for storing the control word if the ANDing operation yields a logical ZERO. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority under 35 U.S.C §119 to PCT/JP2008/055976 filed Mar. 27, 2008, the entire contents of which are hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a honeycomb structure.
[0004] 2. Description of the Related Art
[0005] Conventionally, as a honeycomb catalyst used for purifying exhaust gas of vehicles, platinum is carried on a layer made of activated alumina and the like having a larger specific surface area, the layer being formed on a surface of a honeycomb structure made of cordierite. Further, as a honeycomb catalyst for converting exhaust gas of diesel engines, NOx storage agent is further carried so as to treat NOx in an oxygen-enriched atmosphere.
[0006] The NOx storage agent, however, is more likely to stably store SOx rather than NOx. Because of this feature, SOx poisoning in which the NOx storage agent stores SOx occurs and, disadvantageously NOx cannot adequately stored.
[0007] To solve the problem, according to Japanese Patent Laid-Open Publication No. 6-58138, a sulfur capturing device is provided in an exhaust gas passage on an upstream side with respect to the place where NOx storage agent is provided. The sulfur capturing device includes a sulfur absorbing agent and a casing enclosing the sulfur absorbing agent. As the sulfur absorbing agent, a noble metal such as platinum in addition to any one metal selected from a group consisting of an alkali metal such as potassium, sodium, lithium, and cesium, an alkali-earth metal such as barium an calcium, and a rare earth metal such as lanthanum and yttrium are carried on alumina carrier. Further, a honeycomb structure as described in WO 05/063653A is disclosed.
[0008] The contents of Japanese Patent Laid-open Publication No. 6-58138 and WO 05/063653A are incorporated by reference in their entirety.
SUMMARY OF THE INVENTION
[0009] According to an aspect of the present invention, a honeycomb structure includes at least one honeycomb unit having a longitudinal direction. The honeycomb unit includes SOx storage agent, inorganic particles, inorganic binder, and a partition wall extending along the longitudinal direction to define plural through holes. An expression Y≧−26X+40000 (0<X≦approximately 500) is satisfied, wherein “X” represents an amount [g] of SOx stored in the honeycomb structure, and “Y” represents a specific surface area [m 2 /L] of the honeycomb structure when “X” [g] of SOx is stored in the honeycomb structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1A is a perspective view showing an example of a honeycomb structure according to an embodiment of the present invention;
[0011] FIG. 1B is a perspective view showing a honeycomb unit in FIG. 1A ;
[0012] FIG. 2 is a perspective view showing another example of the honeycomb structure according to another embodiment of the present invention; and
[0013] FIG. 3 is a graph showing relationships between a specific surface area per unit volume and SOx storage amount in honeycomb structure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] Next, exemplary embodiments of the present invention are described with reference to the accompanying drawings.
[0015] FIGS. 1A and 1B show an example of a honeycomb structure 10 according to an embodiment of the present invention. As shown in FIG. 1A , the honeycomb structure 10 includes plural honeycomb units 11 . Each honeycomb unit 11 has partition walls and plural through holes 12 within the partition walls. The honeycomb units 11 are arranged in a longitudinal direction of the honeycomb structure 10 and are adhered to each other by interposing adhesive layers 13 provided between the honeycomb units 11 . An outer peripheral surface of the honeycomb structure 10 is covered with an outer coating layer 14 . In this configuration, the honeycomb unit 11 includes SOx storage agent, inorganic fibers, and inorganic binder. Further, a specific surface area Y[m 2 /L] of the honeycomb structure 10 when X[g] of SOx is stored therein satisfies the following relationship:
[0000] Y≧− 26 X+ 40000 (0 <X≦approximately 500)
[0000] When this relationship is satisfied, it becomes easier to control the degradation of SOx storing performance caused by heating the honeycomb structure 10 . Because of this feature, by disposing the honeycomb structure 10 on the upstream side of a honeycomb structure 10 that includes NOx storage agent, it becomes easier to control the SOx poisoning of the NOx storage agent.
[0016] When the limit of the dispersion of SOx storage agent and the like is taken into account, the specific surface area Y[m 2 /L] is preferably equal to or less than approximately 70000 [m 2 /L].
[0017] The SOx storage agent is not specifically limited as long as the SOx storage agent reacts with SOx and stores the SOx as sulfate. The SOx storage agent may be any one of an alkali metal such as sodium and potassium and an alkali-earth metal such as magnesium, calcium, and barium or a combination thereof.
[0018] It should be noted that the SOx storage agent may be included in the partition wall of the honeycomb unit 11 or be supported on the partition wall. Further, the SOx storage agent may be partially included in the partition wall of the honeycomb unit 11 and partially be supported on the partition wall. In this case, the SOx storage agent included in the partition wall may be the same as or different from the SOx storage agent be supported on the partition wall.
[0019] Preferably, the content of the SOx storage agent in the partition wall of the honeycomb structure 10 is in the range of approximately 1.0 mol/L to approximately 2.5 mol/L. When the content of the SOx storage agent in the partition wall is equal to or more than approximately 1.0 mol/L, it may become easy to maintain the performance of storing SOx, thereby facilitating the reduction of the size of the honeycomb structure 10 . On the other hand, when the content of the SOx storage agent in the partition wall is equal to or less than approximately 2.5 mol/L, the manufacturing the honeycomb structure 10 is apt to be less difficult.
[0020] The inorganic particles are not specifically limited as long as the inorganic particles are made of inorganic compound excluding the SOx storage agent and capable of increasing the specific surface area of the honeycomb structure 10 to allow the SOx storage agent to store SOx more easily. The inorganic particles may be alumina, titania, silica, zirconia, ceria, mullite, zeolite, and the like or a combination thereof. Especially, it is most preferable to use alumina.
[0021] Preferably, the average particle diameter of the inorganic particles is in the range of approximately 0.1 μm to approximately 10 μm. When the average particle diameter is equal to or more than approximately 0.1 μm, it becomes not necessary to add a large amount of inorganic binder. As a result, it may not become difficult to perform extrusion molding. On the other hand, when the average particle diameter is eaual to or less than approximately 10 μm, the effect of increasing the specific surface area of the honeycomb assembly 10 may not become insufficient.
[0022] The content of inorganic particles in the honeycomb unit 11 is preferably in the range of approximately 30 wt % to approximately 90 wt %, more preferably in the range of approximately 40 wt % to approximately 80 wt %, and still more preferably in the range of approximately 50 wt % to approximately 75 wt %. When the content of inorganic particles is equal to or more than approximately 30 wt %, the specific surface area of the honeycomb unit 11 may be hardly decreased. On the other hand, when the content of inorganic particles is equal to or less than approximately 90 wt %, the strength of the honeycomb unit 11 may hardly be reduced.
[0023] The inorganic binder is not specifically limited, but may be solid content included in alumina sol, silica sol, titania sol, liquid glass, sepiolite, attapulgite, and the like or a combination thereof.
[0024] The content of inorganic binder in the honeycomb unit 11 is preferably in the range of approximately 5 wt % to approximately 50 wt %, more preferably in the range of approximately 10 wt % to approximately 40 wt %, and still more preferably in the range of approximately 15 wt % to approximately 35 wt %. When the content of inorganic binder is equal to or more than approximately 5 wt %, the strength of the honeycomb unit 11 may hardly be reduced. On the other hand, when the content of inorganic particles is equal to or less than approximately 50 wt %, molding may hardly become difficult
[0025] More preferably, the honeycomb unit 11 further includes inorganic fibers. By doing this, the strength of the honeycomb unit 11 may become easier to improve.
[0026] The inorganic fibers are not specifically limited as long as the strength of the honeycomb unit 11 can be improved. The inorganic fibers may be alumina, silica, silicon carbide, silica-alumina, glass, potassium titanate, aluminum borate, and the like or a combination thereof.
[0027] The aspect ratio of the inorganic fibers is preferably in the range of approximately 2 to approximately 1000, more specifically in the range of approximately 5 to approximately 800, and still more preferably in the range of approximately 10 to approximately 500. When the aspect ratio is equal to or more than approximately 2, the effect of improving the strength of the honeycomb unit 11 may hardly be reduced. On the other hand, when the aspect ratio is equal to or less than approximately 1000, clogging or the like may hardly occur during molding such as extrusion molding. Further, inorganic fibers may hardly be broken during molding, thereby hardly reducing the effect of improving the strength of the honeycomb unit 11 .
[0028] The content of the inorganic fibers in the honeycomb unit 11 is preferably in the range of approximately 3 wt % to approximately 50 wt %, more preferably in the range of approximately 5 wt % to approximately 40 wt %, and still more preferably in the range of approximately 8 wt % to approximately 30 wt %. When the content of the inorganic fibers is equal to or more than approximately 3 wt %, the effect of improving the strength of the honeycomb unit 11 may hardly be reduced. On the other hand, when the content of the inorganic fibers is equal to or less than approximately 50 wt %, the specific surface area of the honeycomb unit 11 may hardly be decreased.
[0029] The area of a cross section perpendicular to the longitudinal direction of the honeycomb unit 11 , namely perpendicular to the through holes 12 , is preferably in the range of approximately 5 cm 2 to approximately 50 cm 2 . When the cross-sectional area is equal to or more than approximately 5 cm 2 , the specific surface area of the honeycomb unit 11 may hardly be decreased and the pressure loss of the honeycomb unit 11 may hardly be increased. On the other hand, when the cross-sectional area is equal to or less than approximately 50 cm 2 , the strength against the thermal stress produced in the honeycomb unit 11 may hardly become insufficient.
[0030] The thickness of the partition wall separating the through holes 12 of the honeycomb units 11 is preferably in the range of approximately 0.05 mm to approximately 0.35 mm, more preferably in the range of approximately 0.10 mm to approximately 0.30 mm, and still more preferably in the range of approximately 0.15 mm to approximately 0.25 mm. When the thickness of the partition wall is equal to or more than approximately 0.05 mm, the strength of the honeycomb unit 11 may hardly be reduced. On the other hand, when the thickness of the partition wall is equal to or less than approximately 0.35 mm, the performance of storing SOx may hardly be reduced because exhaust gas can easily penetrate inside the partition wall.
[0031] Further, the number of through holes 12 per 1 cm 2 of cross section perpendicular to the longitudinal direction of the honeycomb unit 11 is preferably in the range of approximately 15.5 to approximately 186, more preferably in the range of approximately 46.5 to approximately 170.5, and still more preferably in the range of approximately 62.0 to approximately 155. When the number of through holes 12 per 1 cm 2 is equal to or more than approximately 15.5, the strength of the honeycomb unit 11 may hardly be reduced. On the other hand, when the number of through holes 12 per 1 cm 2 is eaual to or less than approximately 186, the pressure loss of the honeycomb unit 11 may hardly be increased.
[0032] The thickness of the adhesive layers 13 adhering the honeycomb units 11 with each other is preferably in the range of approximately 0.5 mm to approximately 2 mm. When the thickness of the adhesive layers 13 is equal to or more than approximately 0.5 mm, the adhesive strength may hardly become insufficient. On the other hand, when the thickness of the adhesive layers 13 is equal to or less than approximately 2 mm, the specific surface area of the honeycomb unit 11 may hardly be decreased and the pressure loss of the honeycomb structure 10 may hardly be increased.
[0033] The thickness of the outer coating layer 14 is preferably in the range of approximately 0.1 mm to approximately 3 mm. When the thickness of the outer coating layer 14 is equal to or more than approximately 0.1 mm, the effect of improving the strength of the honeycomb structure 10 may hardly become insufficient. On the other hand, when the thickness of the outer coating layer 14 is equal to or less than approximately 3 mm, the specific surface area of the honeycomb structure 10 may hardly be decreased.
[0034] The honeycomb structure 10 in FIG. 1A has a cylindrical shape. However, the shape of the honeycomb structure 10 according to an embodiment of the present invention is not specifically limited to this shape, but may have another shape such as a rectangular pillar shape and a cylindroid shape.
[0035] Similarly, the honeycomb unit 11 has a square pillar shape. However, the shape of the honeycomb unit 11 according to an embodiment of the present invention is not specifically limited to this shape, but preferably may have a shape capable of easily adhering to other honeycomb units such as a hexagonal pillar shape.
[0036] Further, the through hole 12 in FIG. 1B has a square pillar shape. However, the shape of the through holes 12 according to an embodiment of the present invention is not specifically limited to this shape, but may have another shape such as a triangular pillar shape and a hexagonal pillar shape.
[0037] It should be noted that a noble metal catalyst may be supported on the partition wall of the honeycomb unit 11 . The noble metal catalyst is not specifically limited as long as the noble metal catalyst can oxidize SO 2 to SO 3 . The noble metal catalyst may be platinum, palladium, rhodium, and the like or a combination thereof.
[0038] When a sulfur capturing device such Japanese Patent Laid-open Publication No. 6-58138 is used, however, it is necessary to absorb a large amount of sulfur, which necessarily increases the size. To solve this problem, there is provided a honeycomb structure including plural porous honeycomb units as disclosed in International Publication No. WO05/063653. Each honeycomb unit includes first inorganic material (for example, ceramic particles), second inorganic material (for example, inorganic fibers or ceramic particles each having a large particle diameter), and inorganic binder. Further, each honeycomb unit has plural through holes and an outer surface where no opening of the through hole is formed. A plurality of the honeycomb units are adhered to each other in a manner so that the outer surfaces thereof are adhered to each other by interposing sealing layers to form the honeycomb structure. The size of such a honeycomb structure may be easily reduced because of its larger specific surface area.
[0039] When such a honeycomb structure is used for absorbing SOx, unfortunately, due to the heat repeatedly be conveyed from exhaust gas, the specific surface area may be easily reduced and the performance of storing SOx may also be easily reduced.
[0040] In a honeycomb structure according to an embodiment of the present invention, it may become easier to control the degradation of SOx storage performance caused by heat repeatedly be conveyed from exhaust gas.
[0041] Next, an exemplary method of manufacturing the honeycomb structure 10 according to an embodiment of the present invention is described. First, a molding such as extrusion molding is performed using raw material paste including inorganic particles and inorganic binder, and may further include SOx storage agent and inorganic fibers, to form a raw honeycomb molded body having plural through holes 12 extending in the direction parallel to the longitudinal direction of the honeycomb molded body and separated from each other by the partition walls. By doing this, the honeycomb unit 11 having sufficient strength is obtained even if the firing temperature is low.
[0042] It should be noted that the inorganic binder included in the raw material paste is not specifically limited, but may be solid content included in alumina sol, silica sol, titania sol, liquid glass, sepiolite, attapulgite, and the like or a combination thereof.
[0043] Further, organic binder, dispersion medium, molding aid, or the like may be adequately added to the raw material paste as needed.
[0044] The organic binder is not specifically limited, but may be methylcellulose, carboxymethylcellulose, hydroxyethelcellulose, polyethyleneglycol, phenol resin, epoxy resin, and the like or a combination thereof. It should be noted that additive amount of the organic binder is preferably in the range of approximately 1% to approximately 10% with respect to the total weight of the inorganic particles, inorganic fibers and inorganic binder.
[0045] The dispersion medium is not specifically limited, but may be water, organic solvent such as benzene, alcohol such as methanol, and the like or a combination thereof.
[0046] The molding aid is not specifically limited, but may be ethylene glycol, dextrin, fatty acid, fatty acid soap, polyalcohol, and the like or a combination thereof.
[0047] It is preferable that a mixing and kneading operation be performed when the raw material paste is prepared. An apparatus such as a mixer or an attritor may be used for the mixing, and an apparatus such as a kneader may be used for the kneading.
[0048] Next, the thus-obtained honeycomb molded body is dried using a drying apparatus such as a microwave drying apparatus, a hot air drying apparatus, a dielectric drying apparatus, reduced pressure drying apparatus, vacuum drying apparatus, or a freeze drying apparatus.
[0049] Further, the obtained honeycomb molded body is degreased. The degreasing condition is not specifically limited as long as the condition is appropriate in accordance with a kind or amount of organic substance included in the molded body, but is preferably to heating at a temperature of approximately 400° C. for approximately two hours.
[0050] Further, the obtained honeycomb molded body is fired to form the honeycomb unit 11 . The firing temperature is preferably in the range of approximately 600° C. to approximately 1200° C., and more preferably in the range of approximately 600° C. to approximately 1000° C. When the firing temperature is equal to or more than approximately 600° C., the process of sintering process may hardly be difficult, thereby hardly reducing the strength of the honeycomb structure 10 . On the other hand, when the firing temperature is equal to or less than approximately 1200° C., the process of sintering may hardly occur, thereby hardly reducing the specific surface area of the honeycomb structure 10 .
[0051] Next, a paste for the adhesive layers 13 is applied on the outer peripheral surface of the honeycomb units 11 . The plural honeycomb units 11 are sequentially adhered to each other and dried and solidified to form an assembly of the honeycomb units 11 . In this case, after the assembly of the honeycomb units 11 is formed, the assembly of the honeycomb units 11 may be cut into a cylindrical shape and polished. Alternatively, the honeycomb units 11 formed in a fan shape or a square shape in cross section thereof may be adhered to each other to form an assembly of the honeycomb units 11 having a cylindrical shape.
[0052] The paste for the adhesive layers 13 is not specifically limited, but may be a mixture of inorganic binder and inorganic particles, a mixture of inorganic binder and inorganic fibers, a mixture of inorganic binder, inorganic particles and inorganic fibers, or the like.
[0053] Further, the paste for the adhesive layers 13 may include organic binder. The organic binder is not specifically limited, but may be polyvinyl alcohol, methylcellulose, ethylcellulose, carboxymethylcellulose, and the like or a combination thereof.
[0054] Next, a paste for the outer peripheral coating layer 14 is applied on the outer peripheral surface of the assembly of the honeycomb units 11 having a cylindrical shape and dried and solidified. The material of the paste for the outer peripheral coating layer 14 may be the same as or different from that of the paste for the adhesive layers 13 . Further, the composition of the paste for the outer peripheral coating layer 14 may be the same as that of the paste for the adhesive layers 13 .
[0055] Next, the assembly of the honeycomb units 11 with the paste for the outer peripheral coating layer 14 applied thereon is dried and solidified to obtain the honeycomb structure 10 . In this case, when the paste for the adhesive layers 13 and/or the paste for the outer peripheral coating layer 14 includes organic binder, it is preferable to perform degreasing. The conditions for degreasing may be selected as long as the conditions are appropriate in accordance with a kind or amount of the organic substance included in the above-mentioned paste, but is preferably to heat at a temperature of approximately 700° C. for approximately two hours.
[0056] Further, when necessary, SOx storage agent and/or a noble metal catalyst are supported on the partition walls of the honeycomb structure 10 . A method of supporting the SOx storage agent and/or the noble metal catalyst is not specifically limited, but may be an impregnating method or the like.
[0057] FIG. 2 shows another example of a honeycomb structure 20 according to an embodiment of the present invention. The honeycomb structure 20 is the same as the honeycomb structure 10 except that the honeycomb structure 20 includes a single honeycomb unit 11 having plural through holes 12 extending in the direction in parallel to the longitudinal direction of the honeycomb unit 11 and separated from each other by partition walls.
[0058] It should be noted that a honeycomb structure according to an embodiment of the present invention may or may not have the outer peripheral coating layer 14 .
EXAMPLE
Example 1
[0059] First, 1070 g of magnesium oxide as SOx storage agent, 1180 g of γ alumina having an average particle diameter of 2 μm as inorganic particles, 680 g of alumina fibers having an average fiber diameter of 6 μm and an average fiber length of 100 μm as inorganic fibers, 2600 g of alumina sol having solid content of 20 wt % as a component in inorganic binder, and 320 g of methylcellulose as organic binder are mixed and kneaded to obtain raw material paste. Next, the thus-obtained raw material paste is extrusion-molded by using an extrusion molding apparatus to obtain raw honeycomb molded body. Next, the thus-obtained a raw honeycomb molded body is dried by using a microwave drying apparatus and a hot air drying apparatus, then degreased at a temperature of 400° C. for two hours, and then fired at a temperature of 700° C. for two hours to obtain a honeycomb unit having a square pillar shape, sizes of 35 mm (breadth)×35 mm (width)×68 mm (height), plural through holes, the number of the through holes per 1 cm 2 of a cross section perpendicular to the longitudinal direction being 93, and the thickness of the partition walls of 0.2 mm.
[0060] Next, 26 parts by weight of γ alumina having an average particle diameter of 2 μm, 37 parts by weight of alumina fibers having an average fiber diameter of 0.5 μm and an average fiber length of 15 μm, 31.5 parts by weight of alumina sol having solid content of 20 wt % as a component in the inorganic binder, 0.5 parts by weight of carboxymethylcellulose as organic binder, and 5 parts by weight of water are mixed and kneaded to obtain a heat-resisting paste for the adhesive layers 13 .
[0061] The paste for the adhesive layers is applied so that the thickness of the adhesive layer is 1 mm, and the honeycomb units are adhered to each other and dried and solidified to form an assembly of the honeycomb units. Then, the assembly of the honeycomb units is cut into a cylindrical shape by using a diamond cutter in a manner so that the cross section perpendicular to the longitudinal direction is substantially symmetrical with respect to a point. Further, the paste for the adhesive layers 13 is applied on the outer peripheral surface so that the thickness of the outer coating layer is 0.5 mm, dried and solidified at a temperature of 120° C. by using a microwave drying apparatus and a hot air drying apparatus, and degreased at a temperature of 400° C. for two hours to obtain a honeycomb structure having a cylindrical shape, a diameter of 138 mm, and a height of 68 mm (volume: 2L).
[0062] Next, the thus-obtained honeycomb structure is impregnated with platinum nitrate solution, and kept at a temperature of 600° C. for one hour, so that 3 g/L of platinum as a noble metal catalyst is supported thereon. It should be noted that the honeycomb structure on which platinum is carried includes 2.5 mol/L of magnesium oxide.
Example 2
[0063] The same method as in example 1 is repeated except that the average particle diameter of the γ alumina used in preparing the raw material paste is 10 μm to obtain a honeycomb structure on which platinum is supported. It should be noted that the honeycomb structure on which platinum is carried includes 2.5 mol/L of magnesium oxide.
Example 3
[0064] The same method as in example 1 is repeated except that the average particle diameter of the γ alumina used in preparing the raw material paste is 0.1 μm to obtain a honeycomb structure on which platinum is supported. It should be noted that the honeycomb structure on which platinum is carried includes 2.5 mol/L of magnesium oxide.
Example 4
[0065] The same method as in example 1 is repeated except that the contents of magnesium oxide and γ alumina used in preparing the raw material paste are 650 g and 1600 g, respectively, to obtain a honeycomb structure on which platinum is not supported. Further, the thus-obtained honeycomb structure is impregnated with magnesium oxide dispersion, and kept at a temperature of 600° C. for one hour, so that 1.0 mol/L of magnesium oxide is supported thereon.
[0066] Next, the honeycomb structure on which magnesium oxide is carried is impregnated with platinum nitrate solution, and kept at a temperature of 600° C. for one hour, so that 3 g/L of platinum as a noble metal catalyst is supported thereon. It should be noted that the honeycomb structure on which platinum is carried includes 2.5 mol/L of magnesium oxide.
Comparative Example 1
[0067] A honeycomb structure is obtained, having a cylindrical shape and made of cordierite having sizes of 138 mm (diameter) and 68 mm (height) (volume: 2L), plural through holes, the number of the through holes per 1 cm 2 of a cross section perpendicular to the longitudinal direction being 93, the thickness of the partition wall of 0.2 mm, and a layer made of alumina formed on the surface of the partition walls. Next, the thus-obtained honeycomb structure is impregnated with magnesium oxide dispersion, and kept at a temperature of 600° C. for one hour, so that 2.5 mol/L of magnesium oxide is supported thereon.
Comparative Example 2
[0068] The same method as in example 1 is repeated except that the average particle diameter of the γ alumina used in preparing the raw material paste is 20 μm to obtain a honeycomb structure on which platinum is supported. It should be noted that the honeycomb structure on which platinum is carried includes 2.5 mol/L of magnesium oxide.
[Measurement of Specific Surface Area]
[0069] First, a specific surface area per unit volume of the honeycomb structure having a SOx storage amount “X” of 0 g is measured. Next, simulation gas at a temperature of 400° C. is supplied at a space velocity (SV) of 50000/hour to the honeycomb structure. When the SOx storage amount “X” reaches 150 g, 300 g, and 500 g, the honeycomb structure is taken out so that each of the specific surface areas per unit volume is measured. It should be noted that the components of the simulation gas are nitrogen (balance), carbon dioxide (10 vol %), oxygen (10 vol %), nitrogen monoxide (200 ppm), carbon monoxide (0 vol %), hydrocarbon (200 ppm), and sulfur dioxide (125 ppm).
[0070] Specifically, first, a ratio “A” [vol %] of the volume of the honeycomb structure to the apparent volume of the honeycomb structure including the volume of through holes is calculated. Next, a BET specific surface area “B” [m 2 /g] of the honeycomb structure is measured. The BET specific surface area is measured by using a BET measurement apparatus, Micromeritics Flow Sorb II-2300 (SHIMAZU Corporation), in accordance with the one-point method conforming to Japanese Industrial Standards JIS-R-1626(1996). It should be noted that 2 g of crushed particles from a sample cut from the honeycomb structure is used in measuring the BET specific surface area. Further, apparent density “C” [g/L] of the honeycomb structure is calculated from the weight and the apparent volume of the honeycomb structure. Then, the specific surface area per unit volume of the honeycomb structure “Y” [m 2 /L] is calculated by the following formula
[0000] Y=A/ 100 ×B×C
[0000] TABLE 1 below shows the results of the measurement.
[0071] The entire contents of JIS-R-1629(1996) are hereby incorporated herein by reference.
[0000]
TABLE 1
SPECIFIC SURFACE AREA [m 2 /L]
SO x
SO x
SO x
SO x
SO x
STORAGE
STORAGE
STORAGE
STORAGE
LEAKAGE
AMOUNT: 0 g
AMOUNT: 150 g
AMOUNT: 300 g
AMOUNT: 500 g
AMOUNT
EXAMPLE 1
46400
42000
38000
33000
◯
EXAMPLE 2
43700
39800
35600
31000
◯
EXAMPLE 3
48000
43500
39200
34300
◯
EXAMPLE 4
45300
40800
36800
31500
◯
COMPARATIVE
14300
13000
11800
10200
X
EXAMPLE 1
COMPARATIVE
41800
37000
32300
26000
X
EXAMPLE 2
[0072] Further, FIG. 3 shows the relationships between a specific surface area per unit volume and SOx storage amount “X” in honeycomb structure.
[Measurement of SOx Leakage Amount]
[0073] SOx concentration in the gas from the honeycomb structure is measured using “MEXA-7100D” and “MEXA-1170SX” (both: HORIBA Ltd.) (detection limit: 0.1 ppm) until the SOx storage amount reaches 500 g, while simulation gas at a temperature of 400° C. is introduced at a space velocity (SV) of 50000/hour to the honeycomb structure. The results of the measurement is shown in Table 1. It should be noted that “◯” or “×” marks are indicated when SOx concentration in the gas from the honeycomb structure is 12.5 ppm or less or more than 12.5 ppm, respectively. In this case, when the SOx concentration in the gas from the honeycomb structure is 12.5 ppm, since the content of sulfur dioxide in the simulation gas is 125 ppm, the conversion rate becomes approximately 90%.
[0074] The above description shows that a sulfur dioxide conversion rate in a honeycomb structure according to the examples 1 through 4 of the present invention is equal to or more than approximately 90% when the following relation
[0000] Y≧− 26 X+ 40000 (0 <X ≦approximately 500)
[0000] is satisfied. In this case, it becomes possible to control the degradation of storing SOx caused by heating.
[0075] Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teachings herein set forth. | A honeycomb structure includes at least one honeycomb unit having a longitudinal direction. The honeycomb unit includes SOx storage agent, inorganic particles, inorganic binder, and a partition wall extending along the longitudinal direction to define plural through holes. An expression Y≧−26X+40000 (0<X≦approximately 500) is satisfied, wherein “X” represents an amount [g] of SOx stored in the honeycomb structure, and “Y” represents a specific surface area [m 2 /L] of the honeycomb structure when “X” [g] of SOx is stored in the honeycomb structure. | 1 |
BACKGROUND OF THE INVENTION
This invention relates to a method and apparatus for monitoring a redundant (or standby) transmitter in a radio communications system having an active transmitter and one or more receivers. The invention is especially, although not exclusively, concerned with point-to-multipoint radio communications systems.
Radio transmission systems are often used to transmit data. A common scenario is the transmission of data from a base station to a number of receivers in a point-to-multipoint system. Such an arrangement is shown in FIG. 1 , in which the base station (BS) communicates with a number of terminal stations (TS 1 -TS 3 ) in one particular sector 10 of the base station's range. To reduce the impact of equipment failure (i.e., to increase the availability of a radio link) it is known practice to install duplicate equipment (standby equipment) that is redundant whilst the equipment functions correctly. In the case of a point-to-multipoint system, since the integrity of the base-station transmitter facility is of prime importance, it is that transmitter that is normally duplicated. This is illustrated in FIG. 2 , in which the active and passive (redundant or standby) transmitters are basically identical and comprise an indoor part (IDU) and a cable-linked outdoor part (ODU). The ODU includes an RF stage and an antenna 11 . Where failure of the active transmitter occurs, the redundant (standby) transmitter can take over the transmission of data.
There is the possibility, however, that the redundant transmitter will fail before the active transmitter fails. This is especially likely when the redundant transmitter is permanently energised (so-called “hot standby”). Failure then has a probability of 50%. If failure of the redundant transmitter is not detected, the redundancy is lost and, in the event that the active equipment also fails, data transmission is completely lost. This is obviously particularly disastrous in point-to-multipoint systems, since a whole sector can be lost with the failure of the base station.
There is, therefore, a need to monitor the integrity of the redundant transmitter in such a communications system.
The supervision of a redundant transmitter, however, poses an acute problem, as a transmitter can only be fully tested by transmitting a signal, which in turn may adversely affect the transmission of data.
At the present time, three methods of supervision are known:
the data signal uses both transmitters (active and redundant) at different frequencies or time slots. This is possible only in point-to-multipoint systems if the data signal in the downlink is “bursty”, i.e. if different time slots are employed for different terminal stations, or if it is an FDM (Frequency-Division Multiplex) signal, i.e. different frequency bands are used for different terminal stations. a pilot signal is transmitted over the redundant transmitter, either in the time or frequency domain. This is, however, a waste of resources. the outdoor unit (ODU) is self-monitoring, i.e. the supervision is performed only at the analogue part of the transmitter, for example by monitoring the oscillators. This requires a special development of the redundant ODU and a digital link between the redundant ODU and IDU (indoor unit). Further, this involves additional hardware outlay, which can be costly.
Since in the case of a TDMA (Time-Division Multiple Access) point-to-multipoint system the downlink signal is time-continuous, the first method for supervision cannot be used. The other two have the drawback that they are inefficient.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention there is provided a method for monitoring the redundant transmitter of a radio communications system, which system comprises an active transmitter for the transmission of data signals to one or more receivers, the method being characterised by the steps of: during normal operation transmitting over the redundant transmitter a spread-spectrum signal within the frequency band of the data signal, said spread-spectrum (SS) signal being of low spectral power in comparison with said data signals; and at one or more of the one or more receivers, detecting the presence of the spread-spectrum signal, the absence thereof being taken to indicate the non-integrity of the redundant transmitter.
The invention provides the advantage that a pilot (or monitoring) signal can be transmitted over the redundant transmitter without disturbing the data signal being transmitted by the active transmitter. At the receiver, as far as the data signal is concerned the SS signal is registered merely as additional white noise and is therefore negligible. The receiver, however, also contains means for specifically detecting the SS signal and, if it is not present, it can be concluded that the redundant transmitter is defective.
A particular advantage of the invention is its universal applicability (it does not depend on the nature of the data signal), the fact that it does not waste time or frequency resources, and its susceptibility to digital realisation, so that it is also cost-effective. Further, the ODU does not have to be specially designed and no measurement setup or link between the ODU and the IDU has to be provided.
Preferably detection for the presence of the spread-spectrum signal is performed by a process of correlation.
Advantageously detection is performed by a process of cross-correlation, the spread-spectrum signal being provided by feeding the redundant transmitter with a first pseudo-noise signal and the cross-correlation being performed between the received signal and a second pseudo-noise signal, the second pseudo-noise signal having the same characteristics as the first. With such a method the first pseudo-noise signal is preferably passed through the same components in the redundant transmitter as would data signals, were the redundant transmitter called upon to take over from the active transmitter.
Advantageously, and in order to compensate for a timing phase error in respect of the spread-spectrum signal, oversampling of the received signal is performed in the receiver.
Preferably, and in order to compensate for the effects of a frequency offset existing between the active and redundant transmitters and to take into account the narrow allowable window of offset which the correlation of a long pseudo-noise sequence can tolerate, the received signal is subjected to a stepped sweeping operation, wherein the received function is multiplied by a complex factor having the form exp{j2πkδ S /η}, where j=√−1, k is the sampling index, η is an oversampling factor and δ S are the sweeping steps, scaled by the symbol rate.
Preferably the sweeping steps δ S are chosen such as to cover all values of the frequency offset and are advantageously chosen such as to compensate for a drift of the frequency offset with time.
Preferably the cross-correlation is two-dimensional, and is calculated for all sweeping steps δ S and for ηN pn time steps, where η is the oversampling factor and N pn is the length of the pseudo-noise sequence. Advantageously a maximum of the absolute value of the cross-correlation result is employed to determine the integrity of the redundant transmitter.
In one embodiment a maximum of the squared absolute value of the cross-correlation result is employed to determine the integrity of the redundant transmitter.
Preferably the correlation calculation is performed by a part-serial, part-parallel processing of the sampled data. With such a method the processing preferably takes the form of a processing of a first group (N S ) of the ηN pn points in parallel for successive values of δ S , then of a second group (N S ) of the ηN pn points in parallel for successive values of δ S , and so on until all ηN pn points have been covered.
In a preferred application of the method of the present invention the radio communications system comprises two or more receivers, each of which provides an indication of the presence or absence of the spread-spectrum signal, the decision as to the non-integrity of the redundant transmitter being taken on the basis of the indications of a predetermined number of the two or more receivers.
Advantageously the decision is taken on the basis of a majority vote.
Alternatively the radio communications system comprises one receiver and the indication of non-detection of the spread-spectrum signal at that receiver is taken as an indication of the non-integrity of the redundant transmitter.
The present invention finds particular application to point-to-multipoint radio communications system in which the active and redundant transmitters are part of a base station, and the receivers are terminal stations, of that point-to-multipoint system. Preferably the point-to-multipoint system comprises a TDMA (Time-Division Multiple Access), a FDMA (Frequency-Division Multiple Access) or a CDMA (Code-Division Multiple Access) system.
Alternatively the invention can be applied to point-to-point systems incorporating a redundant or standby transmitter.
According to a second aspect of the invention there is provided apparatus for monitoring the redundant transmitter of a radio transmission system, which system comprises an active transmitter for the transmission of data signals to one or more receivers, the apparatus comprising: means for generating a pseudo-noise signal; means for applying said pseudo-noise signal to an input of the redundant transmitter, the transmitter thereby transmitting a spread-spectrum signal having a low spectral power in comparison with said data signals; and means in one or more of the one or more receivers for detecting the presence of the spread-spectrum signal.
Advantageously one or more receivers includes correlator means for the cross-correlation of the received signal.
Preferably the one or more receivers further comprises oversampling means for the compensation of a timing phase error in respect of the spread-spectrum signal.
Advantageously the apparatus further comprises sweeping means for subjecting the received signal to a frequency-sweeping operation, the sweeping means comprising a multiplier means for multiplying the received signal by a complex factor having the form exp{j2πkδ S /η}, where j=√−1, k is the sampling index, η is an oversampling factor and δ S are the sweeping steps, scaled by the symbol rate.
Preferably the correlator means is connected to a maximum-deriving means for deriving a maximum value of the correlator output. With such an arrangement the maximum-deriving means is advantageously arranged to derive the maximum of the absolute value of the correlator output or the maximum of the square of the absolute value of the correlator output.
According to a further aspect of the invention a radio communications system comprises an active and a redundant transmitter, two or more receivers and an apparatus in accordance with the second aspect of the invention.
Preferably the monitoring apparatus of such a communications system comprises a decision-making means fed by the indications of redundant-transmitter integrity delivered by the receivers. Preferably the decision-making means makes a decision on the basis of majority voting among the receivers.
The communications system preferable comprises a point-to-multipoint system such as a TDM/TDMA (Time Division Multiplex in a downlink/Time Division Multiple Access in an uplink direction) system, an FDM/FDMA (Frequency Division Multiplex in a downlink/Frequency Division Multiple Access in an uplink direction) system or a CDM/CDMA (Code Division Multiplex in a downlink/Code Division Multiple Access in an uplink direction) system.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will now be described, by way of example only, with reference to the drawings, of which:
FIG. 1 is a simplified diagram of a point-to-multipoint radio communications system;
FIG. 2 shows the use of an active and passive (redundant) transmitter in a base station of the point-to-multipoint system of FIG. 1 ;
FIG. 3 is a block diagram of a radio communications system employing the monitoring method in accordance with the invention;
FIG. 4 is a complex-plane diagram illustrating the action of the mapper shown in FIG. 3 ;
FIG. 5 is an equivalent model of the communications system of FIG. 3 ;
FIG. 6 is a sin(x)/x diagram showing the effect of the presence of a frequency offset between the active and redundant transmitters;
FIG. 7 is the equivalent model of FIG. 5 , but including a sweeping technique for compensating for the effects of frequency offset;
FIG. 8 is a further illustration of the sweeping technique mentioned in connection with FIG. 7 ;
FIGS. 9 and 10 are, respectively, a diagram illustrating the deleterious effect of frequency-offset drift and a method of compensating for this effect;
FIG. 11 is a block diagram depicting the correlation process that occurs in an embodiment of the invention;
FIG. 12 shows a method of correlation which involves part-serial, part-parallel processing of data;
FIG. 13 is the block diagram of FIG. 11 , expanded to include the serial/parallel correlation procedure illustrated in FIG. 12 , and
FIG. 14 is a diagram illustrating a particular structural realisation of the serial/parallel correlation technique.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 3 , FIG. 3 is a block diagram of a radio link featuring the monitoring method of the invention and includes both active and passive (redundant/standby) paths in the transmitter and the receiver. The transmission stages are the same in both paths and include a mapping stage 12 , an interpolation stage 13 , a digital-to-analogue converter stage 14 and an IF/RF output stage 15 which feeds an antenna 16 . The modulation scheme which is used is a linear one, e.g. quadrature amplitude modulation (QAM).
Describing the function of the illustrated components in a little more detail, the bits (data symbols) which are to be transmitted are first mapped into channel symbols in the mapper 12 . Assuming, for example, that a 4QAM or a QPSK (Quadrature Phase Shift Keying) modulation scheme is employed, the channel symbols are made to correspond to one of the four points in the complex plane shown in FIG. 4 , i.e. two bits of the wanted data bit stream (symbol stream) to be transmitted are mapped onto one of these four symbols, yielding for that symbol two complex values (real and imaginary) at the output of the mapper. There then occurs a pulse-shaping process using a square-root Nyquist filter (interpolation stage) 13 . The output of this filter 13 is sampled and converted into analogue form ( 14 ). In order to satisfy the sampling theorem, the sampling rate must be at least twice the channel symbol rate, and therefore an oversampling factor-of-η interpolation function is performed, which is included in the pulse-shaping block (interpolation stage) 13 . Finally, the baseband signal is up converted to IF and then to RF ( 15 ) before being transmitted from the antenna 16 .
The data signal is transmitted over the active path.
While the redundant transmission path is substantially identical to the active path in all hitherto described respects, in one respect it is different: at the input of the mapper 12 a switch 17 is provided which makes it possible during normal operation to feed in a spread-spectrum (SS) signal at symbol rate, but, following failure of the active transmitter, to take over transmission of the data signal.
The SS signal consists of a long pseudo-noise (PN) sequence (±1 in amplitude) of length N pn . The signal is up sampled with an oversampling factor η. As the digital filters and analogue components in the active and passive line card and ODU are essentially the same, the SS signal will have the same bandwidth as the data signal. However at the air interface its spectral density will be significantly lower than the density of the data signal (about 30-35 dB lower). Thus, for the data signal the PN sequence appears only as an additional, but negligible, white noise.
At the receiver side the signal received at a receiver antenna 18 is down converted again to baseband ( 19 ) and changed from analogue form to digital ( 20 ), following which a corresponding interpolation step is performed ( 21 ), the resulting signal being, in accordance with conventional methods, subject to a synchronisation and equalisation process ( 22 ), thereby producing the data signal originally transmitted by the active transmitter. In addition to this, however, steps are taken to detect the SS signal that is being transmitted by the redundant (passive) transmitter. This is achieved by correlating the received signal with the same PN sequence that was used by the transmitter. This is shown by the separate branch 23 , which is taken to a correlation stage 24 , the result of the correlation process being used to make a decision as to whether or not the SS signal was received. (It is noted that the received signal comprises both the transmitted data signal and the SS signal). In practice it is the maximum of the absolute value of the correlation which is used to form the decision.
The decision stage ( 24 ) draws the following conclusions:
(a) where both data and SS signals are registered, the ODUs ( 11 , 15 , 16 ) of both active and passive transmitters are deemed to be intact;
(b) where the data signal only is registered, the redundant ODU is considered to be defective;
(c) where the SS signal only is registered, the active ODU is taken to have failed (this applies to the time just before redundancy switching takes place). The switching over of control from active unit to redundant unit is not addressed by this present patent.
This simple approach is rendered more complex by the need to solve two problems which have been found to arise in a practical system:
(1) The frequency synchronisation which can normally be employed in the case of the data signal is missing in the case of the SS signal. This causes a degradation of the correlator output of the form sin (πδM/η/(πδM/η) where δ is the frequency offset scaled by the symbol rate, M is the correlation length and η is the oversampling factor.
(2) There is a similarly missing timing synchronisation for the SS signal, which also causes a degradation of the correlator output, depending on the oversampling factor: the larger the factor η, the smaller the degradation.
Even if a frequency and timing phase synchronisation is provided for the radio link, it is optimised for the active path only. As the oscillators in the active and passive IDU and ODU are not coupled, the frequency offsets will not be the same. Furthermore, the radio channels for the data and SS signal will not be the same. The sampling phase at the receiver will be optimised for the data signal, so that there can be a timing phase error for the SS signal.
The impact of frequency offset and timing phase error on the correlation is now examined and the solution presented. A baseband signal representation is assumed.
The effect of a frequency offset in the time domain is a phase rotation of every sample by a constant factor
2 π δ η
with respect to the previous sample:
s k ′ = s k · exp ( j · 2 π · k Δ f f A ) = s k · exp ( j · 2 π · k δ η ) ( 2.1 )
where η=f A /f S is the oversampling factor, δ=Δf/f S is the frequency offset Δf scaled to the symbol rate f S and f A is the sampling rate.
Referring to FIG. 5 there is shown an equivalent model of the communications system of FIG. 3 in which r k and s k are the data signal and the SS signal respectively, both oversampled with η. Let h A and h P be the impulse responses of the whole active and passive transmission path, respectively, and δ A and δ P the resulting frequency offsets scaled to the symbol rate. The simplification of concentrating all filters at the beginning of the transmission path and all frequency offsets at the end is based on the fact that filtering and frequency offset can be interchanged if the filter bandwidth of the receiver filter is large compared to the frequency offset and if the frequency offset is small compared to changes of the filter function in the frequency domain.
Let M be the correlation length and k o an arbitrary starting index. The output φ ys (n) of the correlator is:
φ
ys
(
n
)
=
1
M
·
∑
k
=
k
0
k
0
+
M
-
1
y
k
·
s
k
-
n
*
(
2.2
)
Expressing y k by convolution we have:
φ
ys
(
n
)
=
∑
l
h
pl
·
1
M
·
∑
k
=
k
0
k
0
+
M
-
1
s
k
-
1
·
s
k
-
n
*
·
exp
(
j
·
2
π
·
k
δ
p
η
)
+
∑
l
h
Al
·
1
M
·
∑
k
=
k
0
k
0
+
M
-
1
r
k
-
1
·
s
k
-
n
*
·
exp
(
j
·
2
π
·
k
δ
A
η
)
(
2.3
)
The mean value of the correlator output is therefore (assuming that s k and r k are uncorrelated):
E [ φ ys ( n ) ] = σ s 2 · h p n · 1 M · ∑ k = k 0 k 0 + M - 1 exp ( j · 2 π · k δ p η ) ( 2.4 )
σ S 2 is the variance (or power) of the SS signal. Transforming the sum and considering only the absolute value, we have finally:
E [ φ ys ( n ) ] = σ s 2 · h p n · si ( π δ p η M ) ( 2.5 )
where si(x)=sin(x)/x. This is a very important result. It shows that, when a frequency offset is present, the “usual” correlator output σ S 2 h P n is distorted by a si-function of the product
δ p η M
(see also FIG. 6 ). Obviously, for large M, si
( δ p η M )
will be close to zero and the correlation φ ys will become very small. In this case, the SS signal would not be detected. However, there is a region for δ P where detection is possible, i.e. where the degradation can be tolerated. Unfortunately, the correlation length has to be quite large in order to detect the SS signal with its very low power, so the acceptable δ P is too small.
The proposed solution according to the invention is to carry out a “sweeping” process, where an intentional and stepwise changing frequency offset δ S is introduced before the correlator. The correlation is calculated for a number N d of offsets, thus covering the whole range of δ P . FIG. 7 reproduces the equivalent model of FIG. 5 , but this time with the additional sweeping function. It should be noted that the correlator output φ ys (n, δ S ) is now two-dimensional, being a function of η and δ S .
Let δ 0 be the frequency offset with acceptable degradation. If the step size is 2 δ 0 , then one of the resulting offsets |δ p +δ S (i 0 )|≦δ 0 so that the degradation of E[φ ys (n, δ S (i 0 ))] will be sufficiently small (see FIGS. 6 and 8 ).
The sweeping function is illustrated in graphical form in FIG. 9 . Here the full range of discrete offsets, δ 1 . . . δ 6 (it is assumed in this example that N d =6), is applied in turn, each offset being effective for an actual frequency offset of ±δ 0 about that applied offset. Each δ S is applied for a time Δt 0 , this being the time over which correlation takes place for that value of δ S .
The effect of this offset compensation can be illustrated also by a numerical example. Assume δ P covers a range from −5 to +5, then the sweeping steps must also vary from −5 to +5. If δ 0 =0.5, the step size is 1 and δ S (i) assumes the values −5, −4, −3, . . . 3, 4, 5. So if, for example, δ P has an actual value of 3.2, then the resulting offset for the particular value of δ S (i 0 )=−3 is −0.2, which is (taking the absolute value) smaller than S 0 . If δ P =3.5, the resulting offset will be −0.5, which is still within the desired range. If δ P =3.6 and δ S (i) is still −3, the resultant offset will be −0.6, which is now too great; hence the correct value of δ S will in this case be −4, yielding an acceptable resultant offset value of −0.4.
In addition to the frequency offset, there is another effect of non-ideal oscillators: the frequency drift. The output of the oscillators not only has an offset Δf, but this offset is also changing in time (drifting). It is:
Δ
f
.
=
∂
Δ
f
∂
t
=
f
s
·
δ
.
p
(
2.6
)
This effect is illustrated in FIG. 9 by the inclusion of two particular values of actual frequency offset δ P1 and δ P2 . The actual offset without drift, 30 , is, as might be expected, a horizontal line, whereas with drift the same characteristic assumes a gradient; this is the line 31 . As shown, line 31 passes through region 32 , which means that offset is being compensated for. However, line 33 shows another possible characteristic in which, because of drift, no region is being passed through, neither region 32 nor region 34 . Under such circumstances frequency offset would remain uncompensated.
In order, in this situation, to “catch” the offset in one sweep excursion from −δ max . . . δ max , the invention provides for the sweeping steps to be adapted so that the regions δ S (i)−δ 0 . . . δ S (i)+δ 0 overlap, as shown now in FIG. 10 . The overlapping Δδ 0 has to satisfy the inequality:
δ . p = Δ f . f s ≤ Δδ 0 Δ t 0 ( 2.7 )
where, as already mentioned, Δt 0 is the time needed to calculate φ ys (n, δ S (i)).
For examining the effect of a timing phase error on the output of the correlation receiver only the redundant path is of importance. The frequency offset is assumed to be zero. From FIG. 5 , and ignoring z k , we may write the received signal as a time-continuous function:
y
(
t
)
=
∑
k
=
-
∞
∞
s
k
·
h
p
(
t
-
k
·
T
A
)
(
2.8
)
If y(t) is sampled with sampling time T A and phase error τ, it follows that:
y
n
=
y
(
n
·
T
A
+
τ
)
=
∑
k
=
-
∞
∞
s
k
·
h
p
[
(
n
-
k
)
·
T
A
+
τ
]
=
∑
l
=
-
∞
∞
s
n
-
l
·
h
p
(
l
·
T
A
+
τ
)
(
2.9
)
From (2.9) we can see that the timing phase error leads to a modified impulse response of the transmission channel:
h′ P1 =h′ P ( lT A )= h P ( lT A +τ) (2.10)
h P1 is the discrete impulse response of the passive transmission path, including all filters from the square-root Nyquist filter 13 at the transmitter to the similar filter 21 at the receiver (see FIG. 3 ).
The phase error appears to behave like a sampling phase error with the discrete-time representation of h P (t). We can therefore take it into account by making all calculations using h′ P1 instead of h P1 . The mean value of the correlator output will be:
| E[φ ys ( n )]|=σ S 2 ·|h P ( n·T A +τ)| (2.11)
Note, that the maximum phase error is τ max =T A /2, so we may decrease τ by increasing the sampling rate. i.e. η.
As has been described above, in order to handle the frequency offset, the cross correlation of the received signal and the PN sequence has to be calculated for N d sweeping points, in addition to the ηN pn “time” points. Thus, the correlation function is two-dimensional: φ ys (−n, δ S (i))=φ(n, i), n=0, . . . ηN pn −1, i=1, . . . N d . For this section, η=2 is assumed. FIG. 11 shows the principle of the correlation unit: the received signal y k+k0 is rotated by a complex factor exp(jπδ S (i)k) and then multiplied by the over-sampled output of the same shift register, as in the transmitter. M values at a time are accumulated (M is the correlation length), the division by M giving the cross correlation:
φ
(
n
,
i
)
=
1
M
·
∑
k
=
0
M
-
1
y
k
0
+
k
·
s
k
0
+
k
+
n
*
·
exp
[
j
·
π
·
δ
s
(
i
)
·
k
]
=
φ
ys
[
-
n
,
δ
s
(
i
)
]
(
2.12
)
There are two main ways of calculating φ(n, i): all serial or all parallel. All serial means that the points in the two dimensional space (n, i) are calculated one after another. All parallel means that all values of φ(n, i) are calculated at once. The all-serial method requires the least outlay in terms of hardware, but is slow; the all-parallel method is fast, but incurs greater hardware outlay. The preferred embodiment of the invention employs a compromise solution, in which calculations are carried out in a partly serial, partly parallel manner. This brings with it a trade-off between speed and outlay.
The scheme actually envisaged by the invention is shown schematically in FIG. 12 . A first block of N S values of n is taken (in the example shown, N S =8) and all N d values of i are calculated successively for this block. This is shown by the arrow A. Then the next block of N S time steps follows, in which again all N d values of i are calculated one after the other; this is the arrow B. The process continues until all N pn values of n have been covered.
This serial/parallel scheme necessitates an amendment to the correlation calculation diagram shown in FIG. 11 . In the amendment (see FIG. 13 ) the stages between the δ S rotation operator 25 and the maximum-value block 26 are duplicated, one for each value of δ S . Hence there are N S blocks altogether, each fed from the rotation operator 25 and feeding the maximum-value block 26 . The latter detects which of the units 1 . . . N S is outputting the greatest absolute value.
A more detailed realisation of this same scheme is shown in FIG. 14 , where again N S =8. The figure illustrates the calculation of the first block (n=0, . . . N S −1) for δ S (i). The shift register is synchronised with the symbol time T S =1/f S and cycles continuously with period N pn . For the calculation of the first N S time steps, the first N S /2 (i.e. 4) values of the shift register are read out.
Since the PN sequence is oversampled by η=2, every second value of s k is zero and does not have to be multiplied by r k . To take this into account, switches are provided before the accumulators, which are synchronised by the sampling time T A =T S /2, where T S is the symbol time. After a time MT A the contents of the N S accumulators are divided by M, giving the correlations. Out of every N S correlation values the maximum of their squared absolute value is calculated (alternatively, the absolute value alone may be calculated, but its square has the advantage of incurring less hardware outlay) and compared with the stored maximum of the previous sequence of N S correlation values. The larger value is then kept as the new maximum. The accumulators are set to zero and δ S takes on the next value. After t=MT A N d , δ S again assumes its first value and the next block of N S /2 outputs of the shift register is read out. By comparing the maximum of all correlator outputs (i.e. their squared absolute value) with a given threshold, a decision can be formed as to whether the SS signal has been sent or not.
The described principle of monitoring a redundant transmitter by a SS signal can be used for point-to-point systems as well as for point-to-multipoint systems. However, in point-to-multipoint systems the following additional and beneficial feature can be introduced. At each terminal within a sector the correlation and detection unit described above is provided. Each terminal makes a decision as to whether the SS signal is present or not and the decision is transmitted to the base station. Only if a predetermined number of terminals indicated that the SS signal had not been received is an alarm then given to the network management system. Preferably the alarm is only given where at least half of all the terminals gave a negative report, i.e. majority voting. Such averaging over all the terminals allows the requirements of the correlator in each terminal to be relaxed (the correlation length may be reduced, for example), without reducing the reliability of the supervision. | A method for monitoring a redundant (passive) transmitter, being, for example, part of a base station of a point-to-multipoint radio communications system transmits, during normal operation, a spread-spectrum signal over the redundant transmitter, the spread-spectrum signal being of low spectral power in comparison with data signals being transmitted by the active transmitter of the base station. One or more receivers are associated, for example, with terminal stations in communication with the base station and detect the presence of the spread-spectrum signal. If the spread-spectrum signal is not found to be present, the receivers provide an indication of this, and from this indication, a decision is made as to the integrity of the redundant transmitter. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 61/883,146, filed on Sep. 26, 2013, the disclosure which is incorporated herein by reference.
FIELD
The present disclosure relates to furniture and, more specifically, to a modular laboratory furniture and assembly and manufacture thereof.
BACKGROUND
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In these days of rapidly evolving technology and developing science, laboratories are challenged to increasingly adapt and change their laboratories space to the changing needs of the various projects from time to time. This requires an increasing adaptable and flexible furniture solution that is unique to laboratories. These require the integration and distribution of services such as electrical, gas, and other fluids to each work station that may also change or need to be easily changed. Existing modular furniture systems are often costly to reconfigure or change to meet the ever changing requirements of the modern laboratory.
SUMMARY
The inventors hereof have succeeded at designing a new and improved modular furniture assembly, system and method that provides laboratories with increased flexibility and lower cost of modification and changes over the life of the modern laboratory. These include features that all for improved flexibility in floor space utilization as well as installation and removal of work station services. These and other benefits will be apparent to one of skill in the art upon reading the following specification and in view of the numerous exemplary embodiments described herein and in the drawing figures.
According to one aspect, In one embodiment, system for modular laboratory furniture having a work surface having a front edge, a back edge, two opposing side edges, a top surface and a bottom surface with a subassembly positioned below the work surface and on which the work surface is mounted and supported, the subassembly having a back surface support and two opposing side surface supports and a pair of front legs. The system further includes a pair of back leg members each selectively couplable to the subassembly proximate to opposing back corners of the subassembly proximate to the intersection of one of the side work surface supports and an end of the back work surface support, each back leg member having an elongated cavity along a length of the back leg member extending downward from a top end thereof and a portion of an outer side that is positioned facing outward from the side edge of the work surface and defining an elongated vertical opening into the elongated cavity of each back leg member. The system also includes a selectively attachable upper framework positionable above the back edge of the work surface, the upper framework having two opposing vertical support members supporting at least one horizontal member that extends between the two vertical support members, each vertical support member having a top end, a lower end, a vertical elongated cavity along its length, a cross-section that is about twice the size of a cross section of one of the back leg members, and an outward facing vertical elongated opening to the cavity, the cavity configured for receiving one or more utility distribution fixtures. The system further includes a mounting mechanism for mounting the lower end of the vertical support members of the upper framework to a top portion of the back leg members.
According to another aspect, wherein the work surface, subassembly, and the pair of front legs are each a first work surface, a first subassembly and a first pair of front legs, respectively. The system further includes a second work surface, a second subassembly, and a second pair of front legs, the second work surface being oriented 180 degrees from the first work surface with the back edges of each work surface being positioned adjacent to each other. The back leg members are dimensioned and configured for attachment to the back portions of each of the first and second subassemblies for commonly supporting both the first and second work surfaces, and for mounting the vertical support members.
According to another aspect, a system for modular laboratory furniture includes a leg support assembly having a pair of opposing leg members with an elongated cavity along a length extending downward from a top end thereof and a portion of an outer side that is positioned facing outward and defining an elongated vertical opening into the elongated cavity of each leg member, the leg support assembly having a lateral member positioned between the two opposing leg members and having a surface mounting member positioned at a bottom end. The system also includes a selectively attachable upper framework positionable above the lateral member and having two opposing vertical support members supporting at least one horizontal member that extends between the two vertical support members, each vertical support member having a top end, a lower end, a vertical elongated cavity along its length, and an outward facing vertical elongated opening to the cavity, the cavity configured for receiving one or more utility distribution fixtures and a mounting mechanism for mounting the lower end of the vertical support members of the upper framework to the top portion of the back leg members.
According to yet another aspect, a method of assembling modular laboratory furniture includes the process of attaching a work surface having a front edge, a back edge, two opposing side edges, a top surface and a bottom surface to a subassembly position below the work surface and on which the work surface is mounted and supported. The method also includes steps of attaching a pair of front legs to the subassembly, and selectively coupling a pair of back leg members to the subassembly proximate to a back corner of the subassembly proximate to the intersection of one of the side lateral supports and an end of the back lateral support, each back leg member having an elongated cavity and a portion of an outer side that is positioned facing outward from the side edge of the work surface defining an elongated vertical opening into the elongated cavity of the leg member. The method further includes selectively attaching an upper framework above the back edge of the work surface, the upper framework having two opposing vertical support members supporting at least one horizontal member that extends between the two vertical support members, each vertical support member having a top end, a lower end that is selectively coupled to a top portion of one of the back leg members, the upper framework also having a vertical elongated cavity along its length and a cross-section that is about twice the size of a cross section of each back leg member, and an outward facing vertical elongated opening to the cavity, the cavity configured for receiving one or more utility distribution fixtures; and securing each vertical support member to one of the back leg members. The attaching the vertical support members of the upper framework can also include inserting an extending member of the lower end of the vertical support member into a top cavity defined in the top portion of the back leg members.
Further aspects of the present disclosure will be in part apparent and in part pointed out below. It should be understood that various aspects of the disclosure may be implemented individually or in combination with one another. It should also be understood that the detailed description and drawings, while indicating certain exemplary embodiments, are intended for purposes of illustration only and should not be construed as limiting the scope of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 includes FIGS. 1A, 1B, 1C and 1D . FIG. 1A is a top perspective view of a modular laboratory furniture system according to one exemplary embodiment. FIG. 1B is a front view of a modular laboratory furniture system according to the exemplary embodiment of FIG. 1A . FIG. 1C is a side view of a modular laboratory furniture system according to the exemplary embodiment of FIG. 1A . FIG. 1D is a top view of a modular laboratory furniture system according to the exemplary embodiment of FIG. 1A .
FIG. 2 is a top perspective view of certain unassembled components of the module furniture system according to the exemplary embodiment of FIG. 1 .
FIG. 3 is a side cut out perspective view of the coupling of the vertical support member of the upper framework to a back leg member according to the exemplary embodiment of FIG. 1 .
FIG. 4 is side view of FIG. 3 according to the exemplary embodiment of FIG. 1 .
FIG. 5 is a bottom view of the single back leg mounted or attached to the work surface and supporting subassembly without the attached vertical support member being mounted thereto according to the exemplary embodiment of FIG. 1 .
FIG. 6 includes FIGS. 6A and 6B that are views of the horizontal member of the upper framework according to the exemplary embodiment of FIG. 1 .
FIG. 7 is a top view of the vertical support member of the upper framework along with the attachment of the horizontal member thereto according to the exemplary embodiment of FIG. 1 .
FIG. 8 is a bottom view of the back leg member according to the exemplary embodiment of FIG. 1 .
FIG. 9 includes FIGS. 9A, 9B, 9C and 9D . FIG. 9A is a top perspective view of a modular laboratory furniture system according to another exemplary embodiment. FIG. 9B is a front view of a modular laboratory furniture system according to the exemplary embodiment of FIG. 9A . FIG. 9C is a side view of a modular laboratory furniture system according to the exemplary embodiment of FIG. 9A . FIG. 9D is a top view of a modular laboratory furniture system according to the exemplary embodiment of FIG. 9A .
FIG. 10 is a top perspective view of certain unassembled components of the module furniture system according to the exemplary embodiment of FIG. 9 .
FIG. 11 is a side cut out perspective view of the coupling of the vertical support member of the upper framework to two back leg members according to the exemplary embodiment of FIG. 9 .
FIG. 12 is a side view of FIG. 11 according to the exemplary embodiment of FIG. 9 .
FIG. 13 is a bottom view of the two back-to-back back leg members mounted or attached to the work surface and supporting subassembly without the attached vertical support member being mounted thereto according to the exemplary embodiment of FIG. 9 .
FIG. 14 includes FIGS. 14A and 14B . FIG. 14A is a side view of the lower portion of the back to back leg members according to the exemplary embodiment of FIG. 9 . FIG. 14B is a bottom view of the lower portion of the back to back legs according to the exemplary embodiment of FIG. 9 .
FIG. 15 includes FIGS. 15A, 15B, 15C and 15D . FIG. 15A is a top perspective view of a modular laboratory furniture system according to another exemplary embodiment. FIG. 15B is a front view of a modular laboratory furniture system according to the exemplary embodiment of FIG. 15A . FIG. 15C is a side view of a modular laboratory furniture system according to the exemplary embodiment of FIG. 15A . FIG. 15D is a top view of a modular laboratory furniture system according to the exemplary embodiment of FIG. 15A .
FIG. 16 is a top perspective view of certain unassembled components of the module furniture system according to the exemplary embodiment of FIG. 15 .
FIG. 17 is a side cut out perspective view of the coupling of the vertical support member of the upper framework to two back leg members according to the exemplary embodiment of FIG. 15 .
FIG. 18 is a side view of FIG. 17 according to one embodiment of the exemplary embodiment of FIG. 15 .
FIG. 19 a bottom view of the two back-to-back back leg members mounted or attached to the work surface and supporting subassembly without the attached vertical support member being mounted thereto according to the exemplary embodiment of FIG. 15 .
FIG. 20 includes FIGS. 20A, 20B and 20C each of which are various views of a free standing standalone service distribution assembly according to one exemplary embodiment thereof.
It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
DETAILED DESCRIPTION
The following description is merely exemplary in nature and is not intended to limit the present disclosure or the disclosure's applications or uses.
In one embodiment, system for modular laboratory furniture having a work surface having a front edge, a back edge, two opposing side edges, a top surface and a bottom surface with a subassembly positioned below the work surface and on which the work surface is mounted and supported, the subassembly having a back surface support and two opposing side surface supports and a pair of front legs.
The work surface and the subassembly can define a back leg member mounting receptacle for receiving a back leg member. The subassembly can include one or more leg attachment mounting fixtures positioned for selective alignment with one or more of the leg mounting fixtures.
The various fasteners or mounting mechanisms or the like described herein, such as the leg attachment mounting fixtures, by way of example, can be any available and reasonable suitable fastening means and at any suitable location but in some embodiments at least a top section of the front legs are fixedly coupled to the subassembly. These fastening mechanisms can include bolts, screws, hooks and slots, clips, adhesive, by way of example only and not meant to be limited thereto.
The system further includes a pair of back leg members each selectively couplable or mountable to the subassembly proximate to opposing back corners of the subassembly proximate to the intersection of one of the side work surface supports and an end of the back work surface support. Each back leg member has an elongated cavity along a length of the back leg member extending downward from a top end thereof and a portion of an outer side that is positioned facing outward from the side edge of the work surface and defining an elongated vertical opening into the elongated cavity of each back leg member.
The system also includes a selectively attachable upper framework positionable above the back edge of the work surface, the upper framework having two opposing vertical support members supporting at least one horizontal member that extends between the two vertical support members, each vertical support member having a top end, a lower end, a vertical elongated cavity along its length, a cross-section that is about twice the size of a cross section of one of the back leg members, and an outward facing vertical elongated opening to the cavity, the cavity configured for receiving one or more utility distribution fixtures.
The system further includes a mounting mechanism for mounting the lower end of the vertical support members of the upper framework to a top portion of the back leg members. In some embodiments, the mounting mechanism of each back leg member can include a top cavity and the lower end of each vertical support member can include a mating extended portion for inserting into the top cavity of the back leg member on which the vertical support member is mounted.
In some embodiments, each of the back leg members is a first back leg member and the system further includes a second back leg member selectively secured to the first leg portion forming a back leg assembly. The second back leg member has an elongated cavity and a portion of an outer side that is positioned facing outward from the side edge of the work surface. The elongated cavity of the second back leg member combines with the elongated cavity of the first leg member to define a widened elongated back leg cavity and also forms an elongated vertical opening defined by their combination of the side by side leg member openings. The vertical support member of the upper framework is mounted on the back leg assembly and is attached thereto for supporting and securement of the upper framework above the back edge of the work surface.
In some embodiments, each upper portion of at least one of the first or second back leg members of the back leg assembly on either side of the work surface includes a top cavity. In some cases, each of the two vertical support members of the upper frame includes at least one extending mounting member configured to be received into the top cavity of the back leg. At least of the upper vertical support member and one of the first or second back leg members of the back leg assembly includes a securing fixture for mounting the extending mounting member of the vertical support member thereto.
In some embodiments, a cavity cover is dimensioned and configured for selectively covering the elongated combined vertical openings of both the vertical support member of the upper framework and the elongated vertical openings of the back leg members, whether in the single back leg member embodiment or the back to back combination forming the back leg assembly as described herein. Of course it should be understood that in the alternative, one cover can be configured separately for the elongated vertical opening of the vertical support member with a separately attachable leg member opening cover for covering the leg member opening.
In some embodiments, the work surface is a first work surface, and each second back leg member is a back leg member supporting a second work surface oriented 180 degrees back to back with the first work surface with a back edge of the second work surface being adjacent to the back edge of the first work surface.
In some embodiments, the back leg members of each of the first and second work surfaces are selectively coupled together to form a unified back to back work surface with the upper framework positioned above the back edge of the first work surface and the back edge of the second work surface.
In some embodiments, each of the pair of back leg members on each opposing side of the work surface is a first back leg member. The system can also include a pair of second back leg members each of which is coupled or is couplable to a back portion of one of the first back leg members for forming a back leg assembly. The back leg assembly in the single work surface embodiment will have the second back leg member extending backward and outward from the back edge of the work surface. The upper portion of each of the first and second back leg members can include a mounting mechanism for mounting the lower end of one of the vertical support members.
In some embodiments, the front legs can include an upper section and a lower section selectively coupled to the upper section. The upper section can have a proximate end coupled to the subassembly and the lower end coupling to the lower section. The lower section can have a distal end engaging a floor surface on which the furniture system is placed. In some embodiments, at least one of the upper section and lower section includes a height adjustment fixture for selectively defining a plurality of front leg heights by the selective combination of the upper section and the lower section. Further, since the front leg height can be adjustable by the user, each back leg member can include two or more one leg mounting fixtures proximate to the top end thereof for mounting to the subassembly for selectively mounting at two or more heights the lower leg members thereto. For instance, in some embodiments, at least one fastener coupling the leg to the subassembly using at least one leg mounting fixture and at least one back leg member attachment mounting fixture. The back leg member can include a plurality of leg mounting fixtures positioned spaced apart at various distances along the elongated length of the upper portion of the leg and wherein the leg attachment mounting fixture and leg mounting fixture are configured for selective attachment for fixing the leg to the subassembly at one of a plurality of different positions for varying the height of the back leg member from the work surface to the mounting surface.
In some embodiments, the work surface, subassembly, the pair of front legs and the two back leg members are each a first work surface, a first subassembly and a first pair of front legs, and a first two back leg members, respectively. The system also includes a second work surface, a second subassembly, a second pair of front legs and a second pair of two back legs, the second work surface being oriented 180 degrees from the first work surface with the back edges of each work surface being positioned adjacent to each other, wherein each of the back leg members has at least a portion of a leg-to-leg attachment fixture and wherein each back leg is configured for parallel alignment and coupling of the back leg member of the first work surface to the back leg member of the second work surface for securement thereto. In some embodiments, each pair of coupled back leg members includes an upper portion having a mounting mechanism for mounting a portion of a lower end of one of the vertical support members of the upper frame.
In some embodiments, each upper portion of each coupled leg members includes a top cavity. Each of the two vertical support members of the upper frame includes at least one extending mounting member configured to be received into the top cavity of the back leg member and wherein at least one of the upper vertical support member and one of the first or second back leg members includes a securing fixture for mounting and securing the vertical member of the upper framework to the back leg member. In some embodiments, each back leg member includes a portion of an outer side that is positioned facing away from the side edge of the work surface, and wherein each of the first back leg member and the second back leg member defines an elongated vertical opening into an elongated cavity positioned proximate to each other forming a combined elongated vertical opening there between and combined elongated cavity through the coupling of the two back leg members together.
In some embodiments, a cover is dimensioned and configured for selectively covering the combined elongated vertical opening of the combined first and second back leg members forming the back leg assembly and the elongated opening of the vertical support member mounted thereto.
In some embodiments, the work surface, subassembly, and the pair of front legs are each a first work surface, a first subassembly and a first pair of front legs, respectively. The system further includes a second work surface, a second subassembly, and a second pair of front legs, the second work surface being oriented 180 degrees from the first work surface with the back edges of each work surface being positioned adjacent to each other. The back leg members can be dimensioned for attachment to the back portions of each of the first and second subassemblies for commonly supporting both the first and second work surfaces and for mounting the vertical support members.
In another embodiment, a system for modular laboratory furniture includes a leg support assembly having a pair of opposing leg members with an elongated cavity along a length extending downward from a top end thereof and a portion of an outer side that is positioned facing outward and defining an elongated vertical opening into the elongated cavity of each leg member, the leg support assembly having a lateral member positioned between the two opposing leg members and having a surface mounting member positioned at a bottom end. The system also includes a selectively attachable upper framework positionable above the lateral member and having two opposing vertical support members supporting at least one horizontal member that extends between the two vertical support members, each vertical support member having a top end, a lower end, a vertical elongated cavity along its length, and an outward facing vertical elongated opening to the cavity, the cavity configured for receiving one or more utility distribution fixtures and a mounting mechanism for mounting the lower end of the vertical support members of the upper framework to the top portion of the back leg members.
In another embodiment, a method of assembling modular laboratory furniture includes the process of attaching a work surface having a front edge, a back edge, two opposing side edges, a top surface and a bottom surface to a subassembly position below the work surface and on which the work surface is mounted and supported. The method also includes steps of attaching a pair of front legs to the subassembly, and selectively coupling a pair of back leg members to the subassembly proximate to a back corner of the subassembly proximate to the intersection of one of the side lateral supports and an end of the back lateral support, each back leg member having an elongated cavity and a portion of an outer side that is positioned facing outward from the side edge of the work surface defining an elongated vertical opening into the elongated cavity of the leg member.
The method further includes selectively attaching an upper framework above the back edge of the work surface, the upper framework having two opposing vertical support members supporting at least one horizontal member that extends between the two vertical support members, each vertical support member having a top end, a lower end that is selectively coupled to a top portion of one of the back leg members, the upper framework also having a vertical elongated cavity along its length and a cross-section that is about twice the size of a cross section of each back leg member, and an outward facing vertical elongated opening to the cavity, the cavity configured for receiving one or more utility distribution fixtures; and securing each vertical support member to one of the back leg members. The attaching the vertical support members of the upper framework can also include inserting an extending member of the lower end of the vertical support member into a top cavity defined in the top portion of the back leg members.
In some embodiments, the process of selectively attaching the upper framework can include selectively coupling a lower end of each vertical support member to each of the attached first and second back leg members so that the upper framework is selectively mounted to the attached first and second back leg members. In some embodiments, the process of selectively attaching the upper framework can include inserting a pair of extending members of the lower end of each vertical support member into a pair of top cavities defined in the top portions of each of the first and second back leg members. The method can also include selectively placing a single elongated cover over the vertical elongated opening of the vertical support member and the elongated opening of the back leg member on which the vertical support member is mounted.
In some embodiments, the method includes securing the extending member that is inserted into the top cavity of the top portion of the back leg members for fixedly attaching the upper framework to the back leg members.
In some embodiments wherein the pair of back leg members is a first pair of back leg members, the method can include selectively attaching each of a pair of second back leg members to the first back leg members on a backward facing side thereof with the attached second back leg member extending backward and beyond the back edge of the work surface. The selectively attaching the upper framework can include selectively coupling a lower end of each vertical support member to each of the attached first and second back leg members so that the upper framework is selectively mounted to the attached first and second back leg members. In such embodiments, the method of attaching the vertical support members of the upper framework can include inserting a pair of extending members of the lower end of each vertical support member into a pair of top cavities defined in the top portions of each of the first and second back leg members. The method can also include securing the extending members inserted within the top cavities of the top portions of the back leg members for fixedly attaching the upper framework to the coupled pair of back leg members forming a back leg assembly.
In some embodiments, the method can include selectively placing a single elongated cover over the vertical elongated cavity of the vertical support member and the combined side by side openings of each of the coupled back leg members on which the vertical support member is mounted.
In some embodiments where the work surface, the subassembly, and the pair of front legs are each a first work surface, a first subassembly, a first pair of front legs, the method can include attaching a second work surface to a second subassembly position below the second work surface and on which the second work surface is mounted and supported. This method can include attaching a pair of second front legs to the second subassembly and positioning the coupled second work surface attached to the second subassembly in a back to back position relative to the first work surface so that each back edge is adjacent and abutted against each other and forming a combined work surface. This method can also include selectively attaching the second back legs that are selectively attached to the first back legs to a second subassembly to the second subassembly.
The method can include the process of securing the inserted extending members inserted into the top cavities of the top portions of the back leg members for fixedly attaching the upper vertical members to the coupled pair of back legs on each side of the back side of the combined work surface.
In some embodiments, the method can include selectively placing a single elongated cover over the vertical elongated cavity of the vertical support member and the combined opening formed by the side by side positioning of the elongated openings of the combined and coupled first and second back leg members on which the vertical support member is mounted.
Referring now to the drawings for a description of several exemplary embodiments. FIGS. 1-8 reflect various configurations, features and options referred herein as a first exemplary embodiment. FIG. 1 includes FIG. 1A , a top perspective view of a modular laboratory furniture system 100 , FIG. 1B a front view, FIG. 1C a side view, and FIG. 1D a top view. FIG. 2 illustrated a perspective view of a portion of the unassembled components of the module furniture system 100 of FIG. 1 . FIG. 3 is a side perspective view of cutout section 3 - 3 as shown in FIG. 1A , FIG. 4 is the side cut out view of section 4 - 4 shown in FIG. 1C and FIG. 5 is the top view of cut out section 5 - 5 as shown in FIG. 1D . FIG. 6A illustrates an optional side view showing elongated cover in place and FIG. 6B shows a top view of the detached upper framework. FIG. 7 shows a cut out top view of the vertical support member and the horizontal member of the upper framework of FIG. 6A and FIG. 8 is a bottom view of the back leg member. These Figures will not be described with reference to each and their common and different elements.
As shown, furniture system 100 includes a work surface 102 that has a top surface 110 and a bottom 112 , with a front edge 104 , a back edge 106 and two opposing side edges 108 . This is shown as a rectangle work surface 102 , but other shapes of the work surface 102 are also possible. The work surface 102 is mounted and supported by a subassembly 114 that typically has a back surface support 126 , two opposing side surface supports 128 and can also include a front surface support 127 . The subassembly 114 is supported by front legs 116 and back leg members 118 . As will be discussed, the present disclosure addresses the improvements that are related to the back leg members 118 and the flexibility of the back leg members 118 as well as improvements to these other work surface elements. The back leg members 118 are positioned at the opposing back corners of the work surface 102 such as in a mounting receptacle 170 formed in the work surface 102 and similarly formed in the subassembly 114 . Each back leg member 118 has a top cavity 150 positioned at the top end 154 of the back leg member. Each back leg member 118 has a back surface portion 161 that is substantially flat and also has one or more back leg mounting mechanisms 164 for mounting the back leg members 118 to the subassembly 114 when the back leg member 118 is positioned in the mounting receptacle of the work surface 102 . The leg mounting mechanisms 164 can include a plurality of spaced apart features to enable the attachment of the back leg members 118 to the subassembly 114 at various positions for varying the height of the work surface 102 . The subassembly 114 can include a securing fixture 146 having one or more subassembly mounts 147 for the back leg members 118 for engagement or coupling or otherwise engagement with the back leg mounting mechanisms 164 . These securing fixtures 146 and subassembly mounts 147 can be on the back surface support 126 and/or the side surface support 128 of the subassembly 114 .
As the back leg member 118 includes back leg mounting mechanism 164 for selectively defining the height of the back leg member 118 and therefore the height of the work surface 102 from the mounting surface or floor, the front legs 116 can be configured with a height adjustment feature 212 as well. As shown in FIG. 1B , each front leg 116 can include a top section 202 that is mounted or mountable to the subassembly 114 and a bottom or lower leg section 204 having a distal end 208 for placement or engagement with the mounting surface. A lower portion 206 of the top section 202 can selectively engage an upper portion 210 of the lower section 204 and include fixtures and other configuration for selectively defining the working height of the front legs 116 as necessary to level the work surface 102 consistent with the height of the back leg members 118 as well as the mounting surface.
Each back leg member 118 has an elongated cavity 120 positioned along a length of the back leg member 118 typically extending downward from a top end 154 of the back leg member 118 for receiving one or more user service utilities 222 such as electrical wiring, and piping for gas or water or other fluids. For ease of access, each back leg has an outer side 122 that is positioned facing outward from the side edge 108 of the work surface 102 and also has an elongated vertical opening 124 to the elongated cavity 120 of each back leg member 118 , again for ease of access, maintenance and for modification and changes thereto. A cover 190 is dimensioned and configured for placement over the opening 124 for selectively covering and sealing the opening 124 and for providing an improved aesthetic to the installed furniture system during operation in a laboratory. The back leg member 118 can be of any shape or any size, but in the embodiment shown in FIG. 1 , has a cross sectional area d2 and size such that the back leg member 118 does not extend beyond the back edge 106 of the work surface 102 .
The furniture system 100 also includes a utilitarian distribution center in the form of an upper framework 130 . The upper framework 130 includes two opposing vertical supports or vertical support members 132 and one or more horizontal members 134 . The vertical support members 132 have a top end 136 and a lower end 138 and define an elongated cavity 140 for receiving a maintaining user service utilities as well as in some embodiments one or more utility distribution fixtures 224 , such as electrical outlets, by way of example. The horizontal members 134 can also include one or more distribution fixtures 224 and also include cavities coupled to the cavities 140 of the vertical support members 132 for distribution of the user service utilities 222 there between. One or more shelves 135 can be positioned on the horizontal members 134 as well. An elongated opening 142 is defined in the outwardly facing side or surface of the vertical support 132 for ease of installation and maintenance and removal of the user service utilities 222 from the elongated cavity 140 . The cover 190 can also be dimensioned and configured for selectively covering the opening 142 . The cover 190 can be elongated and dimensioned and configured to selectively cover both opening 142 of the vertical support 132 as well as the opening 124 of the back leg member 118 .
A securing fixture 146 is provided for attaching the vertical support 132 to the back leg member 118 , typically about the top end 154 of the back leg member 118 . In this illustrated embodiment, the upper framework 130 includes an extending member 160 such as a tube 160 that extends downward from the lower end 138 of the vertical support 132 . The back leg member 118 has a top cavity 150 configured for receiving the extending member 160 . One or more mounting fixtures or subassembly mounts 147 are provided with the securing fixture 146 for selectively securing the mounting of the vertical support 132 to the back leg member 118 . The cavity 140 of the vertical support 132 is aligned and continuous with the cavity 120 of the back leg member 118 . Further, the opening 142 of the cavity 140 of the vertical support 132 can also be aligned and continuous with the opening 124 to cavity 120 of the back leg member. In this manner, the user service utilities 222 such as electrical wires and fluid pipes can be placed within the combined cavity 120 , 140 and access from openings 124 , 142 when any cover 190 is not in place.
As shown in this embodiment, the cross sectional area d1 of the vertical support 132 is twice the size from front to back as d2 of the back leg member 118 . As such, when the vertical support 132 is mounted to a single back leg member 118 as shown in FIG. 8 , the vertical support 132 will extend backward and beyond the back edge 106 of the work surface 102 . In this embodiment, the work surface 102 can be dimensioned outwardly to correspond with the back extended end of the back of the vertical support 132 , or in some embodiments, a separate spacer can be placed along the back edge 106 of the work surface to fill in the space so that the work surface 102 can be placed flush against a wall when the back side of the upper framework 130 is also placed against the wall. This also applies in embodiments as will be described in FIG. 9 below, as it generally applies in embodiments where there is a single work surface 102 , e.g., not a dual or back to back work surface as provided by the exemplary embodiment of FIG. 15 as will be discussed below in further detail.
FIGS. 9-14 are now referred to for different embodiment of the furniture system. FIG. 9A is a top perspective view of a modular laboratory furniture, with FIG. 9B being a front view, FIG. 9C a side view, and FIG. 9D being a top view thereof. FIG. 10 is a top perspective view of certain unassembled components of the module furniture system of FIG. 9 . FIG. 11 is a side cut out perspective view of the section 11 - 11 shown in FIG. 9A , FIG. 12 is a side view of the section 12 - 12 shown in FIG. 9C and FIG. 13 is a top view of section 13 - 13 shown in FIG. 9D . FIG. 14A is a side view of the lower portion of the back to back leg members of FIG. 9 , and FIG. 14B is a bottom view of the lower portion of the back to back leg member thereof.
The embodiment illustrated in FIGS. 9-14 is similar to that addressed above with regard to FIGS. 1-8 but are different as the back leg member 118 of the prior discussion is supplemented with a back leg assembly 162 formed from the coupling of a first leg member 118 A and a second leg member 118 B. The back leg members 118 A, 118 B are dimensions and have a cross sectional area d2 that when combined equal or is substantially the same as the cross sectional area d1 of the vertical support 132 . As shown, the first back leg member 118 A has back surface 161 A and second back leg member 118 B has back surface 161 B. When placed in a back to back position as shown in FIG. 13 , the two leg members 118 A, 118 B can be secured together by leg to leg attachment fixtures 152 thereby stabilizing them as the back leg assembly 162 .
In this manner, when the vertical support 132 is mounted to the back leg assembly 162 , the combination provides a continuous cavity 140 into the combined cavity 174 comprised of the back to back placement of the first cavity 120 A of first back leg member 118 A and the second cavity 120 B of the second back leg member 118 B. Further the wider opening 142 of the vertical member can now be continuous with the combined width of the first opening 124 A of the first back leg member 118 A with that of the second opening 124 B of the second back leg member 118 B.
Further, as there is now two back leg member 118 A, 118 B on which to mount the vertical support 132 , the vertical support 132 can include two extending members 160 A and 160 B each for placement in a different top cavity 150 A and 150 B of back legs 118 A and 118 B, respectively. Two securing fixture assemblies 146 A, 146 B include one or more securing subassembly mounts 147 A securing extending member 160 A within cavity 150 A and therefore to back leg member 118 A, and one or more securing subassembly mounts 147 B securing extending member 160 B within cavity 150 B and therefore to back leg member 118 B.
FIGS. 15-19 are now referred to for yet another different embodiment of the furniture system. FIG. 15A is a top perspective view of a modular laboratory furniture, with FIG. 15B being a front view, FIG. 15C a side view, and FIG. 15D being a top view thereof. FIG. 16 is a top perspective view of certain unassembled components of the module furniture system of FIG. 15 . FIG. 17 is a side cut out perspective view of the section 11 - 11 shown in FIG. 15A , FIG. 18 is a side view of the section 18 - 18 shown in FIG. 15C and FIG. 19 is a top view of section 19 - 19 shown in FIG. 15D .
The embodiment illustrated in FIGS. 15-19 represents the flexibility of the presently disclosed furniture system. This embodiment is not a different system, but an assembled variation of the systems as described above with regard to FIGS. 1-14 but having two work surfaces 102 A, 102 B positioned to form furniture system 200 having a combined work surface 180 . When compared to the first embodiment of FIGS. 9-14 , this illustrated system 200 has first work surface 102 A with first mounting receptacle 170 A and first leg member 118 A and first side support 128 A mounted below first side edge 108 A. However, it also has the second back leg member 118 B mounted in place. The second work surface 102 B has side edge 108 B and includes the second receptacle 170 B. The second work surface 102 B is mounted to a second subassembly 114 B that includes the second side supports 128 B and is also supported by second front legs 116 B. In this manner, the second work surface 102 B is positioned 180 degrees relative or in orientation to the first work surface 102 A but with the second back edge 106 B adjacent to and up against the first back edge 106 B thus forming the combined work surface 180 . As shown in FIG. 19 , the back leg assembly 162 includes the back to back positioned first and second leg members 118 A, 118 B coupled along back surfaces 161 A, 161 B by one or more fasteners 152 . The combined cavity 174 is formed by the combined side by side positioning of the first cavity 120 A with second cavity 120 B. Similarly, the combined opening 176 to the combined cavity 174 is formed by the side by side positioning of the first opening 124 A with the second opening 124 B between or on the outer side 122 A of the first leg member 118 A and the outer side 122 B of the second leg member 118 B.
Where the back leg assembly 162 is already installed with the first and second back leg members 118 A and 118 B coupled together, the upper framework 130 can already have been placed or mounted by mounting the vertical member 132 to the back leg assembly 162 as described above. The user service utilities 222 can remain in place with minimal changes. The upper framework 130 also already had the horizontal members 134 in place above the back edge 106 of the first work surface 102 A. Once the second work surface 102 B is mounted via second subassembly 114 B to the second back leg members 118 B, the second shelving 135 B can be added if desired for access by a user of the second work surface 102 B when positioned along second front edge 104 B. This is as opposed to a user positioned along first front edge 104 A that accesses first shelving 135 A.
Referring now to another embodiment shown in the Figures, FIG. 20 consisting of FIGS. 20A, 20B and 20C that are various views of a free standing standalone service distribution assembly 300 .
This embodiment further illustrates the flexibility of the presently disclosed furniture system. The system 300 as shown in FIG. 20 , includes the same upper framework 130 with the vertical supports 132 and the horizontal member 134 as previously discussed, but in system 300 , the upper framework 130 is mounted to a free standing base 302 rather than being mounted to a back leg member 118 that in part supported a work surface 102 . In this embodiment, free standing base 302 has a lower vertical support leg 304 with the cavity 120 and opening 124 as described above for the back leg member 118 . However, the cavity 120 is open at the top end of the vertical support leg 304 . The distal end of the vertical support leg 304 terminates with a mounting to a surface mount 308 , which as illustrated in this embodiment can be an assembly having opposing front and rear surface mount extensions. A horizontal member 306 couples the two opposing vertical support legs 304 .
FIGS. 20B and 20C illustrate the upper framework 130 being mounted onto the free standing base 302 . In this configuration, the system 300 enables a user to utilize the distribution services of the user service utilities within the cavity 140 of the upper framework 130 but removing the work surface 102 and subassembly 114 with front legs 116 therefrom, but utilize other forms of furniture or equipment such as test equipment or systems having their own housings or cabinetry or with other forms of laboratory furniture systems such as legacy furniture. Also as shown in these figures, but as can apply to all embodiments, the service access 220 to external service supplies such as electrical wiring or service, water or gas or the like, can be provided from a top access to the upper frame work 130 for providing to the cavity 140 thereof. Of course, those of skill in the art will understand that service access 220 can also be provided from underneath the floor, or from a wall and as such, the service access 220 can be provided via the back leg members 118 for feeding upward rather than as shown in FIGS. 20B and 20C and feeding downward.
As described with regard to FIGS. 1-20 , the various embodiments and configurations illustrate the flexibility and improvement of laboratory furniture. For example, once an upper framework 130 is installed such as with user services via service access 220 , the user can change the working environment for the system from a single sided work station of system 100 and 200 , to a dual sided work station of system 300 , or remove the work stations altogether and only utilize the free standing system of system 400 . Each provides ease of access to the user service utilities within cavities 140 and 120 and each provides for the aesthetic and protective selective covering of the openings 142 and 124 to the cavities.
When describing elements or features and/or embodiments thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements or features. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements or features beyond those specifically described.
Those skilled in the art will recognize that various changes can be made to the exemplary embodiments and implementations described above without departing from the scope of the disclosure. Accordingly, all matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense.
It is further to be understood that the processes or steps described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated. It is also to be understood that additional or alternative processes or steps may be employed. | Systems and methods of assembly and manufacture of a modular laboratory furniture system having a selectively attachable upper framework assembly and easily adaptable configurations with integrated service distribution. | 8 |
TECHNICAL FIELD
This invention relates to the coding of signals and, more particularly, to a probability estimator for entropy encoding/decoding.
BACKGROUND OF THE INVENTION
It is known that entropy, e.g., arithmetic, encoding and decoding requires a probability estimate of the symbol to be encoded and subsequently decoded. In arithmetic encoding and decoding, more accurate probability estimates result in greater data compression. To this end, it is desirable that the probability estimates adapt to changing underlying symbol probabilities.
Prior known probability estimator arrangements have included some ability to adapt but have been limited in the adaptation rate used because of the need to estimate symbol probabilities with relatively small values. Indeed, the effective adaptation rate in prior arrangements was constant and was independent of the actual values of the probabilities being estimated. This leads to less accurate probability estimates and, consequently, lower efficiency in the encoding and decoding of the symbols.
SUMMARY OF THE INVENTION
The problems and other limitations of prior known probability estimators are overcome, in accordance with an aspect of the invention, by optimizing the rate of adaptation to the estimated probabilities of symbols to be encoded and/or decoded.
More specifically, if the values of the probabilities being estimated are not small a "fast" adaptation rate is realized in generating them and if the values of the probabilities being estimated are small a necessarily slower adaptation rate is realized in generating them.
In a specific embodiment, the adaptation rate is optimized by ideally matching it to the actual probability value being estimated. In particular, the adaptation rate is optimized to be proportional to the inverse of the smallest value probability being estimated. This is achieved, in one example, by first determining whether an at least first characteristic of a set of prescribed parameters meets a prescribed criterion, namely, whether it exceeds an at least first threshold value and if the at least first characteristic exceeds the at least first threshold value, adjusting the set of prescribed parameters in a prescribed manner.
In an exemplary embodiment, the at least first prescribed characteristic is the minimum value of the set of prescribed parameters for a given context and the at least first threshold value is a small value, for example, eight (8). Each element in the prescribed set of parameters is a function of a context sensitive accumulation, i.e., count, of received symbols.
BRIEF DESCRIPTION OF THE DRAWING
In the Drawing:
FIG. 1 shows details of an arrangement employing an encoder and remote decoder employing aspects of the invention; and
FIG. 2 depicts a flow chart illustrating the operation of elements of the adaptive probability estimator employed in the encoder and decoder shown in FIG. 1.
DETAILED DESCRIPTION
FIG. 1 shows details of entropy encoder 101 in simplified block diagram form, including aspects of the invention, which receives data symbols s(k), encodes them into a data stream a(i) and interfaces them to a transmission media 102 for transmission to remote entropy decoder 103. Entropy decoder 103, also including aspects of the invention, interfaces to the transmission media to obtain the receiver data stream and decodes it into replicas of the transmitted symbols s(k). Symbols s(k) include elements [0, . . . , S-1], namely, s(k) ε[0, . . . , S-1]. Thus, the symbols may be multilevel or binary as desired.
Accordingly, encoder 101 includes, in this example, arithmetic encoder unit 104, context extractor 105, adaptive probability estimator 106 and line interface 107. Symbols s(k) and probability estimates p (k) are supplied to arithmetic encoder unit 104 and employed therein in known fashion to generate an encoded data stream a(i). Such arithmetic encoder units are known in the art. See, for example, an article entitled "Compression of Black-White Image with Arithmetic Coding", IEEE Transactions On Communications, VOL. COM.-29, No. 6, June 1981, pages 858-867, and U.S. Pat. No. 4,633,490 issued Dec. 30, 1986 for arithmetic encoders/decoders used to encode and decode symbols having binary elements. Also see an article entitled, "Arithmetic Coding For Data Compression", Communications of the ACM, Volume 30, No. 6, June 1987, pages 520-540, for an arithmetic encoder/decoder used to encode/decode symbols having multilevel elements. Line interface 107 interfaces the encoded data stream a(i) to transmission media 102 which, in turn, supplies the data stream to remote decoder 103. To this end, line interface 107 includes appropriate apparatus for formatting the data stream into the signal format employed in transmission media 102. Some well known examples of possible transmission media 102 are T-carrier trunks, ISDN basic subscriber lines, local area networks and the like. Such line interface apparatus is known in the art.
Context extractor 105 simply obtains the context c(k), where c(k) ε [0, . . . , C-1], of received symbol s(k). That is to say, context extractor 106 generates a unique context (or state) for symbol s(k) based on prior supplied symbols. By way of example, and not to be construed as limiting the scope of the invention, for an image compression system, symbol s(k) is representative of the color of a current pixel to be encoded and the context c(k) may be determined by the colors of prescribed prior pixels. For example, the color of a pixel (P) adjacent and prior to the current pixel in the same line and the color of a pixel (A) in a prior line directly above the current pixel may advantageously be used to generate a context c(k) for symbol s(k) in a binary application. Thus, c(k) is zero (0) if both pixel P and pixel A are white; c(k) is one (1) if pixel P is white and pixel (A) is black; c(k) is two (2) if pixel P is black and pixel A is white; and c(k) is three (3) if both pixels P and A are black. Also, see the U.S. Pat. No. 4,633,490 for another context extractor (state generator) which may be employed in a binary application. It will be apparent to those skilled in the art how such binary context extractors can be extended to obtain the context for multi-level applications. A representation of the extracted context c(k) is supplied to adaptive probability estimator 106.
Adaptive probability estimator 106 is advantageously employed to generate probability estimates p (k)=(p 0 (k), . . . p s-1 (k)) for incoming symbol s(k) ε [0, . . . , S-1] and associated context c(k) ε [0, . . . , C-1]. To this end, adaptive probability estimator 106 maintains an array {n s ,c } having dimensionality S by C, where each element n s ,c of the array is an accumulation, i.e., a "count", of the occurrences of symbol s in context c, and s and c are dummy indices identifying the location of n s ,c in the array. Adaptive probability estimator 106 can be readily implemented by appropriately programming a computer or digital signal processor. It is envisioned, however, that a superior mode of implementation is in a very large scale integrated (VLSI) circuit configuration on a semiconductor chip.
The flow chart shown in FIG. 2 depicts operation of elements in adaptive probability estimator 106 in generating more accurate probability estimates, in accordance with an aspect of the invention, by optimizing the rate of adaptation to the estimated probabilities of symbols to be encoded. Accordingly, operation of adaptive probability estimator 106 is started via start step 201. Thereafter, operational block 202 initializes k=0 and the counts of n s ,c for all s ε [0, . . . , S-1] and c ε [0, . . . , C-1] to be n s ,c =N s ,c, where N s ,c are some predetermined values. Operational block 203 obtains a new context c(k). It is noted that the new context can be the same as a previously obtained context. Then, operational block 204 obtains the sum Z of the counts for the obtained context c(k) for all s ε [0, . . . , S-1], namely ##EQU1## Operational block 205 causes adaptive probability estimator 106 (FIG. 1) to output the probability estimates which are, in turn, supplied to arithmetic encoder unit 104 (FIG. 1). Since, this is the first run these probability estimates are based only on the initialized conditions and the obtained context c(k). In subsequent runs, the probability estimates are based on the sum of the counts, i.e., accumulations, of the occurrences of symbols s(k) for context c(k). Thus, step 205 causes the probability estimates to be output, namely, ##EQU2## Operational block 206 obtains symbol s(k) to be encoded. Operational block 207 causes the count for the obtained symbol s(k) and context c(k) to be incremented by 1, namely, n s (k),c(k) is incremented by 1.
Operational block 208 obtains an at least first and an at least second characteristics of a prescibed set of parameters. In this example, each element of the prescibed set of parameters is a function of a context sensitive accumulation, i.e., count, of received symbols to be encoded. That is, the prescribed set of parameters are "accumulated" occurrences of the symbols s(k) for context c(k), namely, n 0 ,c(k), . . . , n S-1 ,c(k). The at least first characteristic, in this example, is the minimum one of the accumulated occurrences for context c(k), namely,
MIN=MINIMUM{n.sub.0,c(k), . . . , n.sub.S-1,c(k) }. (3)
The at least second characteristic, in this example, is the maximum one of the accumulated occurrences for context c(k), namely,
MAX=MAXIMUM{n.sub.0,c(k), . . . , n.sub.S-1,c(k) }. (4)
Conditional branch point 209 tests to determine, in accordance with an aspect of the invention, if either the at least first characteristic is equal to or greater than an at least first threshold value, namely,
MIN≧T.sub.1, (5)
or the at least second characteristic is equal to or greater than at at least second threshold value, namely,
MAX≧T.sub.2. (6)
It is important to note that the use of the at least first characteristic (MIN) allows, in accordance with an aspect of the invention, the optimization of the adaptation rate of adaptive probability estimator 106 (FIG. 1). In prior arrangements, only a maximum threshold value was employed. A significant problem with such a prior arrangement is that it is necessary to use either a large threshold value so that smaller value probabilities can be represented or a small threshold value to obtain fast adaptation. The small threshold value, however, makes it impossible to represent small value probabilities. Additionally, the large value threshold leads to a relatively slow adaptation rate. These problems are resolved by advantageously employing, in accordance with an aspect of the invention, the at least first characteristic which, in this example, is MIN as set forth in equation (4) and a small threshold value T 1 , which in this example, is eight (8). Thus, in this example, each of the possible symbol occurrences for context c(k), namely, [0, . . . , S-1], must occur at least eight times before the condition of equation (5) is met. Consequently, the use of the at least first characteristic, i.e., MIN, and the at least first threshold value T 1 =8, yields an adaptation rate that is ideally matched to the actual probability value being estimated. By way of example and not to be construed as limiting the scope of the invention, for a binary application and a probability being estimated of one-half (1/2), the accumulated occurrences are adjusted after seeing the context c(k) approximately 8+8=16 times; for a probability being estimated of one quarter (1/4), the accumulated occurrences are adjusted after seeing the context c(k) approximately 8+24=32 times; and for a probability being estimated of one-eighth (1/8), the accumulated occurrences are adjusted after seeing context c(k) approximately 8+56=64 times. Thus, it is seen that the adaptation rate is faster for the larger (not small) probability values being estimated and is necessarily slower for the smaller probability values being estimated. The adaptation rate adjustment will be apparent from steps 209 and 210.
The at least second characteristic, in this example, MAX in accordance with equation (4), is employed in conjunction with the at least second threshold value T 2 to assure against arithmetic overflow in the accumulation of the occurrences of symbols s(k) in context c(k). Unless one of the probabilities being estimated has an unusually small value, MAX will not be the characteristic that causes the parameter adjustment. In one example, the value of T 2 is 2048. It is noted that other characteristics of the set of parameters may also be employed. For example, the sum Z obtained in step 204 could be used in place of MAX.
Thus, returning to step 209 if the prescribed criterion of either the condition of equation (5) (MIN≧T 1 ) or the condition of equation (6) (MAX≧T 2 ) is met, operational block 210 causes an adjustment in the accumulated symbol elements in context c(k). In this example, the adaptation rate adjustment is realized by step 210 in conjunction with step 209 causing a proportionate adjustment of the accumulated values, i.e., counts a so-called halving of the accumulated occurrences for context c(k) for all s ε [0, . . . , S-1], namely, setting
n.sub.s,c(k) =(n.sub.s,c(k) +1)/2. (7)
Although in this embodiment the counts are proportionately adjusted in the same manner when the condition of either equation (5) or equation (6) is met, it would be advantageous in some applications to adjust the counts differently for each of the above conditions. This adjustment proportionately of the accumulated occurrences makes the probability estimates more dependent on more recent occurrences of the symbols in context c(k). Thus, as implied above, by causing, in accordance with an aspect of the invention, the adjustment of the accumulated occurrences to occur in accordance with equation (5), i.e., MIN≧T 1 , the adaptation rate is ideally matched to the actual probabilities being estimated. Again, the adjustment of the accumulated occurrences of symbols s(k) in context c(k) which occurs in response to equation (6), i.e., MAX≧T 2 , is to protect against a possible arithmetic overflow condition in the rare situation when a very small probability value is being estimated.
Thereafter, conditional branch point 211 tests to determine if the symbol s(k) is the last symbol to be encoded/decoded. It is noted that the number of symbols to be encoded is typically known. If not known an indication of the number of symbols would be supplied to adaptive probability estimator 106. If the test result in step 211 is YES, the operation of the elements of adaptive probability estimator 106 is ended via END step 212. If the test result in step 211 is NO, control is returned to step 203 and appropriate ones of steps 203 through 211 are iterated until step 211 yields a YES result.
Returning to step 209, if the test result is NO, control is transferred to step 211 to determine if the symbol s(k) is the last symbol to be encoded (decoded). Again, if the test result in step 211 is YES, the operation of the elements of adaptive probability estimator 106 is ended via END step 212. If the test result in step 211 is NO, increment index k by 1 in step 213, control is returned to step 203 and appropriate ones of steps 203 through 211 are iterated until step 211 yields a YES result.
Decoder 103 includes, in this example, line interface 108, arithmetic decoder unit 109, context extractor 110 and adaptive probability estimator 111. Line interface 108 performs the inverse function of line interface 107 and deformats the incoming signal, in a known manner, to obtain the data stream a(i). Arithmetic decoder unit 109 performs the inverse function of arithmetic encoder unit 104. To this end, the received data stream a(i) and probability estimates p (k) from adaptive probability estimator 110 are supplied to arithmetic decoder unit 109 and used therein in known fashion to obtain the symbols s(k). Again, such arithmetic decoder units are known in the art. See again the article entitled "Compression of Black-White Image with Arithmetic Coding" and U.S. Pat. No. 4,633,490, cited above, regarding binary applications and the article entitled "Arithmetic Coding For Data Compression", also cited above, for multilevel applications. Context extractor 110 is identical to context extractor 105 in structure and operation and is not described again. Similarly, adaptive probability estimator 111 is identical to adaptive probability estimator 106 in structure and operation and is not described again. | In entropy, e.g. arithmetic, encoding and decoding, probability estimates are needed of symbols to be encoded and subsequently decoded. More accurate probability estimates are obtained by controllably adjusting the adaptation rate of an adaptive probability estimator. The adaptation rate is optimized by matching it to the actual probability values being estimated. In particular, the adaptation rate is optimized to be proportional to the inverse of the smallest value probability being estimated. Consequently, if the probability values being estimated are not small a "fast" adaption rate is realized and if the probability values being estimated are small a necessarily slower adaptation rate is realized. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continutation of U.S. Ser. No. 13/764,376 filed Feb. 11, 2013, and hereby incorporated by reference in its entirety. U.S. Ser. No. 13/764,376 is a divisional of US 12/587,537 filed Oct. 7, 2009, and hereby incorporated by reference in its entirety. U.S. Ser. No. 12/587,537 claims the benefit of U.S. Ser. No. provisional patent application Ser. No. 61/195,395, filed on Oct. 7, 2008, entitled “Methods and Apparatus for Controlled Chemical Cycling, Isothermal Polymerase Chain Reaction”, and hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention relates to control of chemical reactions.
BACKGROUND
[0003] Chemical reactions are frequently controlled in specialized ways in order to provide various benefits, such as improved yield, increased reaction rate, analysis of products, etc. One example of an important reaction that is often subject to specialized control is the polymerase chain reaction (PCR). PCR is itself a multi-reaction process which may include several types of chemical processes including DNA denaturation, primer annealing, primer extension (with the aid of an enzyme), and for real time detection may include side reactions such as hybridization (e.g., with a fluorescently labeled oligonucleotide) or intercalation of a fluorescent molecule into polynucleotide. PCR is an essential tool in both biology and medicine, and is the technique of choice for DNA amplification. It is commonly used for the identification as well as quantification of nucleic acids or polynucleotides, in particular of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Exemplary applications are diagnosis of hereditary disease, forensics, gene expression profiling and pathogen detection.
[0004] At the present time, most PCR efforts use “thermal cycling”. In this method, double-stranded nucleic acid is subjected to a three-step thermal cycle where it is denatured, annealed, and extended by the action of a thermostable DNA polymerase. In a typical thermal cycling process, the reaction temperature is cycled between 55 and 94 degrees Celsius, thus reaching a point where ordinary polymerases typically denature. Conventional thermal PCR requires costly and complex equipment and can be difficult to automate in miniaturized devices. It requires significant instrumentation, thermal control, and an expensive, thermostable DNA polymerase. Attempts have been made to avoid thermal cycling in PCR. For example, chemical denaturation (as opposed to thermal denaturation) is considered in U.S. Pat. No. 5,939,291 and in US 2008/0166770.
[0005] Electrokinetic and microfluidic technology have been demonstrated for controlling some aspects of chemical reactions. For example, in US 2008/0000774, several methods for controlling the concentration of chemical reactants in a microfluidic system are considered. Enhancing the concentration of a reactant is often referred to as “focusing” the reactant.
[0006] Although it would be attractive to provide for isothermal PCR in a miniaturized fluidic system, conventional fluidic approaches tend to have difficulty with the specialized requirements of PCR (e.g., the large number of reaction cycles, and the need for tight control of reactant and/or product location). Accordingly, it would be an advance in the art to provide improved chemical reaction control, especially in relation to microfluidic PCR.
SUMMARY
[0007] In the present approach, isotachophoresis (ITP) is exploited to control various aspects of chemical reactions. In ITP, a sample of one or more analytes is typically introduced between a leading electrolyte (LE, containing a leading ion) and a trailing electrolyte (TE, containing a trailing ion). The leading ion, trailing ion and sample components all have the same charge polarity, (i.e., are all anions or cations). Typically, the sample components have effective electrophoretic mobility less than that of the leading ion, but greater than that of the trailing ion. Initially, the sample can be mixed with the LE, with the TE, between the LE and TE, or with both the LE and TE. On application of an electric potential to this system, sample components migrate toward the region between the LE and TE. Typically, these sample ions then form discrete contiguous zones of analyte arranged in order of their (effective) electrophoretic mobilities with the highest mobility nearest the LE. Further details relating to isotachophoresis are described in a text “Isotachophoresis: theory, instrumentation, and applications” by authors Everaerts, F. M., J. L. Beckers, et al., published in Amsterdam and New York by Elsevier Scientific Pub. Co. in 1976, and hereby incorporated by reference in its entirety.
[0008] The simplest applications of ITP to controlling chemical reactions are enhancing the concentration of a reactant and using ITP to move a chemical reaction zone through a system. However, ITP also allows for control of several other significant aspects of chemical reactions, and it is these further aspects that are of interest here.
[0009] In a first aspect, at least one of the reactants of a chemical reaction is confined to an ITP zone, but the resulting product of the chemical reaction is separated from this ITP zone by the ITP process. This amounts to simultaneous reaction and separation operations, where a reaction takes place in the ITP zone, and the product is separated from this zone. The product can be unconfined by the ITP, or it can be confined by the ITP to a separate ITP zone than the reactant zone.
[0010] In a second aspect, one or more reactants of a chemical reaction are confined to an ITP zone, and one or more other reactants of the chemical reaction are not confined to this ITP zone. This amounts to a situation where the un-confined reactants can “flow through” the ITP zone where the reaction takes place. For example, a species with effective mobility higher than the LE can be injected in the TE reservoir. It will then electromigrate through the TE zone, through the sample zone(s), and finally through the LE zone in the channel and into the LE reservoir.
[0011] In a third aspect, ITP is employed to confine at least one reactant of a chemical reaction to an ITP zone, and at least one reactant of the chemical reaction is delivered to the ITP zone in two or more discrete doses.
[0012] All three of the above aspects are relevant to and offer substantial advantages in connection with a preferred embodiment where PCR is carried out using chemical denaturants. It is convenient to refer to such PCR reactions as chemically cycled PCR (ccPCR). The nucleic acids and primers/oligonucleotides of the PCR reaction are confined by ITP, while repeated doses of a nucleic acid denaturant flow through the ITP zone. In many cases, it is preferable to control the ITP zone motion so that it is substantially stationary relative to the walls of the liquid channel. This can be done by opposing the sample electromigration with a pressure-driven and/or electroosmosis-driven counter-flow of the solvent. This can be accomplished by matching the ITP migration velocity with an equal and opposite area-averaged velocity of the solvent (the bulk liquid) in the channel. Creating a substantially stationary ITP zone with respect to the lab can significantly simplify controlling the timing and method of injecting discrete reactant doses into the channel and the monitoring of concentrations of reactants and/or products, e.g., using fluorescent tags. Catalysts and/or enzymes can be provided in the ITP reaction zone in order to alter reaction rates, typically to effectively increase rates.
[0013] The ITP process may be able to simultaneously provide the PCR reaction and separation of PCR reaction constituents. For example, nucleic acid templates can be separated from oligonucleotides by confinement to two separate ITP zones. In some cases an electrophoretic spacer ion can be added that forms a separate ITP zone between the nucleic acid template zone and the oligonucleotide zone, thereby further enhancing the separation of PCR reaction constituents. Preferably, the PCR reaction is carried out at constant temperature, thereby avoiding the complexities associated with thermal cycling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 illustrates a conceptual representation of chemical cycling PCR.
[0015] FIG. 2 illustrates the focusing of DNA with isotachophoresis in chemical cycling PCR conditions.
[0016] FIGS. 3 a - b depict an exemplary method of on-chip chemical cycling PCR.
[0017] FIG. 4 illustrates the correlation of solvent type and concentration with nucleotide melting temperature using the example of 16S rRNA.
[0018] FIGS. 5 a - 5 b illustrate end-point detection and real-time monitoring of chemical cycling PCR.
[0019] FIG. 6 shows monitored DNA concentration results from an experiment.
[0020] FIG. 7 shows an example of suitable apparatus for practicing some embodiments of the invention.
DETAILED DESCRIPTION
Definitions
[0021] The term “nucleic acid” as used herein means a polymer composed of nucleotides (“polynucleotides”), e.g., deoxyribonucleotides or ribonucleotides, or compounds produced synthetically which can hybridize with naturally occurring nucleic acids in a sequence specific manner analogous to that of two naturally occurring nucleic acids, e.g., can participate in Watson-Crick base pairing interactions. The terms “nucleic acid” and “polynucleotides” are used interchangeably.
[0022] The terms “ribonucleic acid” and “RNA” as used herein mean a polymer composed of ribonucleotides.
[0023] The terms “deoxyribonucleic acid” and “DNA” as used herein mean a polymer composed of deoxyribonucleotides.
[0024] The term “oligonucleotide” or “oligo” as used herein denotes single-stranded nucleotide multimers up to about 400 nucleotides in length.
[0025] Hybridization means the combination of complementary, single-stranded nucleic acids into a single molecule. “Hybridizing” and “binding” are used interchangeably.
[0026] “High” denaturant concentrations mean working concentrations of more than 10% v/v or more than 1 M.
[0027] “Low” denaturant concentrations mean working concentrations of ≦10% v/v or ≦1 M.
[0028] FIG. 1 is a conceptual representation of ccPCR. Clouds of high denaturant concentration (one of which is labeled as 102 ) flow in a direction 104 . A DNA template 106 has an ITP electromigration direction 108 that is opposite to direction 104 . As a result of this counter-flow process, template 106 experiences a chemical cycling that can mimic the denaturing and then annealing effects caused by thermal cycling in classical PCR. Locally high denaturant concentration regions melt double-stranded nucleic acid, while locally low denaturant regions allow for polynucleotide annealing and extension.
[0029] During the denaturation, annealing and enzyme-aided extension process, the nucleic acid can be kept stationary in a microfluidic channel by balancing flow velocity 104 with ITP velocity 108 , while being exposed in a counter-flow stream to a series of individual clouds of moving denaturant. This exposes the nucleic acid to alternately high and low concentrations of denaturant. ITP provides focusing of the nucleic acids and protects the nucleic acids from being dispersed during amplification. The nucleic acid can remain stationary with respect to the laboratory frame of reference, while denaturant clouds move with the counter-flow.
[0030] The chemical cycling process can be facilitated through spatial fluctuations in the concentration of the chemical denaturants along a microchannel, which can be created by a flow control scheme, and results from the high electrophoretic mobility of nucleotides and the electrical neutrality of denaturants. Since denaturant clouds are electrically neutral, they are driven forward toward, through, and then away from the nucleic acid zone. The velocity of the nucleic acid zone can be greater or less than that of the “train” of denaturant clouds. The velocity of the nucleic acid zones can also be zero or non-zero relative to the laboratory frame. Preferably, the nucleic acid zone is substantially stationary with respect to the laboratory frame. The nucleic acid zone velocity is different than that of the denaturant clouds because of the electric field and the differing charge state of the denaturant and nucleic acid.
[0031] The enzyme used for extension of the primer can be a heat-labile polymerase or polymerase fragment (lacking 5′->3′ exonuclease activity), e.g. Klenow fragment of DNA polymerase I, or a thermostable polymerase, e.g. Taq DNA polymerase. Chemical denaturants can be used in concentrations >10% to denature and open up double-stranded polynucleotides. Chemical denaturants can be used in concentrations of 0-10% to allow for and to adjust annealing and extension processes.
[0032] Polynucleotide samples can be kept stationary and confined using ITP, while moving electrokinetically through varying concentrations of chemical denaturants. The electromigration velocity of the nucleic acid can be balanced out by the application of a pressure-driven or electroosmosis-driven counter flow of denaturants clouds.
[0033] Several advantages follow from this approach. PCR amplification time can be significantly decreased. PCR system and supporting instrumentation design can be simplified (since no thermal cycling is required). PCR specificity and quantitative accuracy can be increased. PCR costs can be decreased. The tendency of the nucleic acid to be dispersed by the denaturant flow is counter-acted by the ITP process, which ensures stable confinement of the nucleic acids while allowing denaturant flow-through. Amplified products can simultaneously be separated by ITP while amplification is ongoing.
[0034] FIG. 2 shows an example of the focusing of DNA with isotachophoresis in ccPCR conditions. Here LE is the leading electrolyte, TE is the trailing electrolyte, 202 is the DNA template ITP zone, 206 is the oligonucleotide (primer) ITP zone, and 204 is the ITP zone of a non fluorescent spacer (here benzoate) that separates the DNA from the primers, providing PCR product localization. The use of a spacer as shown here can facilitate PCR product localization. The direction of the denaturant counter-flow in this example is shown as 208 .
[0035] FIGS. 3 a - b show an exemplary scheme of on-chip ccPCR in a cross channel 302 . A DNA template zone 312 is confined by ITP between a leading electrolyte LE and a trailing electrolyte TE. A spacer zone 314 and a primer zone 316 are also confined by ITP between the LE and TE, as shown. The ITP velocity is shown as 310 , and is opposite to the direction of fluid flow in the channel such that the ITP zones are roughly stationary with respect to the channel. Two consecutive denaturant clouds are shown as 306 and 308 . They are separated by PCR buffer 307 , which also includes the leading electrolyte and is accordingly labeled as LE. A flow control scheme at the cross using a denaturant reservoir 304 can be employed to provide these periodic clouds of denaturant.
[0036] The situation shown on FIG. 3 a is when a cloud of denaturant (i.e., cloud 308 ) just enters the DNA template zone. The resulting reaction in the ITP zones is schematically shown as double stranded DNA 320 separating into its single strands 322 . The situation shown on FIG. 3 b is after cloud 308 has passed through the ITP zones. The resulting reaction in the ITP zones is schematically shown as single-stranded DNA 322 binding to a primer to provide primed DNA strands 324 , which are then extended to corresponding double stranded DNA 326 by a polymerase.
[0037] A series of clouds (small controlled volumes, doses or “plugs”) of chemical denaturants can be introduced into an amplification channel with a valve and pressure driven flow. During the denaturation, annealing and extension process, the nucleic acid is kept at a velocity different than that of the “train” of denaturant clouds on the microfluidic platform by an electric field. The nucleic acid is kept focused in a relatively small region (relative to channel length) by an electric field gradient that is achieved by isotachophoresis, while being exposed in a counter-flow stream to clouds of moving denaturants of alternately high and low concentrations. Locally high denaturant concentration regions melt the nucleic acid, while locally low denaturant regions allow for nucleic acid annealing and extension. The electric field aids to focus and refocus the nucleic acid and protects the nucleic acid from dispersing during amplification.
[0038] The chemical cycling process can be facilitated through spatial fluctuations in the concentration of the chemical denaturants along a microchannel, which can be created by a pressure-driven flow control scheme, and is achieved through the high electrophoretic mobility of nucleotides combined with the electrical neutrality of denaturants.
[0039] The DNA sample can be initially introduced into a channel section between the two electrolytes used in the isotachophoresis process. Upon application of the electric field, isotachophoresis focuses the sample into a sharp zone.
[0040] Denaturing chemical agents have the ability to reduce the melting temperature of DNA, i.e. the temperature at which double-stranded DNA separates into two complementary single strands. The chemical cycling PCR runs at a temperature at which DNA is single stranded in denaturant, but double stranded in regular buffer (with water only as solvent). High denaturant concentration allows denaturation, while low concentration allows annealing and extension. The denaturants used in one particular embodiment of the invention are formamide and urea. Any other compounds that can act as nucleic acid denaturants can also be employed.
[0041] Non thermostable polymerases such as the Klenow fragment from E. Coli DNA polymerase I have enhanced accuracy compared to thermostable polymerases. Also, the temperature at which their activity is optimum is close to typical room temperature. Chemical cycling in conjunction with non thermostable polymerase has the potential to perform DNA amplification at room temperature with high accuracy.
[0042] The denaturant injection can be controlled by pressure driven flow or electroosmotic flow. For pressure driven flow, denaturant and other buffers can be connected to the inlets of the chip with capillary tubing. Flow can be generated with a hydrostatic pressure head or an automated pressure controller. A valve allows switching off flow between buffer and denaturant. Periodic switching of the valve creates denaturant cycles within the channel. For electroosmotic injection, the chip wells can be filled with buffer and denaturant. Using a four output power supply, the flow can be controlled to create a succession of gated electroosmotic injections of denaturant, while keeping the direction of the electric field the same in the DNA channel throughout the experiment.
[0043] For applications of the present approach to PCR, the PCR buffers have to be compatible with isotachophoresis. Isotachophoresis leverages the difference of electrophoretic mobility of ions to create electric field gradients. Isotachophoresis buffers are not necessarily compatible with the PCR reaction. For PCR/ITP combinations that are untested, initial control experiments to verify compatibility should be performed.
[0044] In some cases, electroosmotic flow allows better control and reproducibility of the injection and reduced dispersion compared to pressure-driven counter-flow. In electroosmotic flow, the surface charge on the channel walls originates the flow upon application of an electric field in the channel.
[0045] In ccPCR, longer double-stranded nucleic acids can be continuously separated from primer-dimers and primers during the amplification reaction using an electrophoretic spacer (e.g., as shown on FIGS. 2 and 3 a - b ), while the fluorescence of the specific PCR product can be monitored for quantitation purposes. An electrophoretic spacer is an ionic species which has properties such that it ends up between the template and the primers in the ITP stack of zones.
Experiment 1: On-Chip Chemical Cycling Polymerase Chain Reaction Using Formamide and Urea as Denaturants
[0046] This assay was performed in a simple cross borosilicate glass microchip (model NS95, Caliper, Mountain View, Calif.) coated with polyvinylpyrrolidone. Off-chip PCR buffer and denaturant reservoirs were connected to a low dead volume switching valve (model C2, Vici Valco, Houston, Tex.). The valve was connected to the chip with nanoports (Upchurch Scientific, Oak Harbor, Wash.) and fused silica capillaries (Upchurch Scientific, Oak Harbor, Wash.). The pressure head between the off-chip reservoirs and the chip drives the flow. The chip was on an electric heater maintained at 55° C. with a Peltier device and a temperature controller (Omega Engineering, Stamford, Conn.). A sourcemeter (model 2410, Keithley, Cleveland, Ohio) was used to apply high voltage and perform ITP.
[0047] The reaction was monitored with an inverted epifluorescent microscope (Eclipse TE300, Nikon) equipped with a cooled CCD camera (Princeton instruments, Trenton, N.J.), and controlled with the data acquisition software V++. Images were processed with MATLAB.
[0048] A 1× PCR Mastermix (Qiagen, Valencia, Calif.) was used as the leading electrolyte (LE). The Mastermix contains 50 mM potassium chloride, 10 mM Tris hydrochloride, 1.5 mM magnesium chloride, 2.5 U/100 μL Taq DNA polymerase, 200 μM of each dNTP. The trailing electrolyte was 25 mM Tris HEPES with 2.5 U/100 μL Taq DNA polymerase (Qiagen, Valencia, Calif.), 200 μM of each dNTP (New England Biolabs, Ipswich, Mass.), and 1.5 mM magnesium chloride. Both LE and TE contain 20 nM of forward and reverse primers (Operon, Huntsville, Ala.), 2 μM SYTO13 intercalating dye (Molecular Probes, Eugene, Oreg.) and 0.01% Tween 20 (Sigma, St Louis, Mo.). The denaturant was 40% formamide 4M urea buffered with 1× PCR buffer and containing 1.5 mM magnesium chloride, 2 μM SYTO13 and 20 nM of each primer. The DNA template (194 by segment 341-534 of the 16S rRNA gene from E. Coli .) was diluted in LE solution.
[0049] A finite amount of DNA template was initially injected hydrodynamically between LE and TE. Then, a voltage was applied to start ITP focusing. Once the template was focused, the voltage was adjusted so that the sample remains stationary in its channel. Then the denaturant cycling was started by actuating the denaturant valve. SYTO13 fluorescence was monitored during the denaturant cycles.
[0050] FIG. 4 illustrates the correlation of solvent type and concentration with nucleotide melting temperature using the example of 16S rRNA. Measured effect of formamide and urea concentration on melting temperature T m of the 16S rRNA gene from E. Coli . T m decreases with increasing urea and formamide concentrations. These results demonstrate the effect of formamide and urea as denaturants.
[0051] FIGS. 5 a - 5 b illustrate end-point detection and real-time monitoring of ccPCR. a) Isotachopherograms of PCR product zone before (left) and after 40 ccPCR cycles (right). This type of end point detection allows identification of DNA sequences of interest. b) Real time fluorescence monitoring of ccPCR. Initially, the PCR product fluorescence signal is below limit of detection.
Experiment 2: Initial PCR/ITP Control Experiments
[0052] A series of calibration experiments were performed to optimize the chemistry and flow conditions. The efficacy of Taq Polymerase was demonstrated for a relatively low extension temperature of 55° C. Final concentrations of three-step classical PCR products of a 200 by template from E. Coli by agarose gel electrophoresis were compared. The PCR trials show very similar yields for extension temperatures of 55° C. and 72° C. demonstrating high Taq activity at 55° C. for the tested template (data not shown). This result shows that annealing and extension are possible at 55° C.
[0053] In a second set of experiments, it was verified that the ITP conditions can result in a buffer compatible with PCR. Buffer type, buffer concentration, and DNA concentration can have a strong effect on PCR efficiency. Ionic concentration was varied by changing the PCR buffer concentration of a three-step classical PCR from 1× to 6× (1× PCR buffer corresponds to 50 mM KCl, 20 mM Tris-HCl) and PCR yields for each concentration were compared by agarose gel electrophoresis. PCR yield decreases dramatically for buffer concentrations greater than about 3× (data not shown). Similar experiments suggest that PCRs in Tris-HEPES buffer with concentrations ranging from 25 mM to 100 mM have similar yields to PCR in a 1× PCR buffer (data not shown).
[0054] A counter flow stream with alternately high and low denaturant concentration was moved through ITP-confined polynucleotide samples, as in FIG. 3 . The counter-flow stream can be pressure driven and/or electroosmotic. Double-stranded DNA (dsDNA) concentration was monitored via SYBR Green I intercalating dye fluorescence and single-stranded DNA (ssDNA) concentration was monitored by SYBR Green II fluorescence. A fused silica microchip with silanized channels was employed, and Tween 20 was added to all solutions to minimize protein adsorption.
[0055] FIG. 6 is a plot of DNA concentration monitored via SYBR Green I fluorescence plotted versus time. Under conditions of balanced electromigration and bulk flow velocity, the DNA plug oscillates within about a 1 mm region. Fluorescent intensity decreases dramatically during denaturing before increasing as DNA amplifies via annealing and extension.
[0056] FIG. 7 shows an example of a device 702 suitable for practicing the above-described ITP/PCR process. A micro-fluidic chip 708 having crossed channels 710 and 712 sits on a plate 704 maintained at a constant temperature of 55° C. at which denaturant activity is optimum. The temperature of plate 704 can be maintained by a Peltier device 706 attached to a heat sink (not shown). Electric field can be applied from HV well 724 to GND well 726 to effect ITP focusing of DNA. PCR buffer flows continuously into chip PCR well 728 via hydrostatic pressure. Denaturant flows into well 722 under control by a valve (not shown) that is actuated in pulses causing small denaturant injection clouds to flow toward the HV well. Voltage is preferably controlled to hold the DNA band approximately stationary via ITP dynamics. The chemical concentration cycling amplification process can monitored in real time by measuring intensity of fluorescence 732 at the end of each amplification cycle with a monitor 730 . Real time fluorescence monitoring can be performed with an epifluorescent microscope and a computer controlled CCD camera. ccPCR product quantity can be determined by intercalating dye fluorescent or by sequence specific fluorescent probe such as molecular beacons.
[0057] The preceding description has been by way of example as opposed to limitation, and various modifications of the given examples also rely on the above-described principles. In particular, the preceding examples relate to the various chemical processes associated with the polymerase chain reaction. However, the use of ITP to control chemical reactions can be applied to any chemical reaction, not just PCR. The preceding examples also relate to the use of micro-fluidic devices. However, standard capillaries and interconnects can also be employed. | Isotachophoresis (ITP) is exploited to control various aspects of chemical reactions. In a first aspect, at least one of the reactants of a chemical reaction is confined to an ITP zone, but the resulting product of the chemical reaction is separated from this ITP zone by the ITP process. In a second aspect, one or more reactants of a chemical reaction are confined to an ITP zone, and one or more other reactants of the chemical reaction are not confined to this ITP zone. In a third aspect, ITP is employed to confine at least one reactant of a chemical reaction to an ITP zone, and at least one reactant of the chemical reaction is delivered to the ITP zone in two or more discrete doses. These aspects are especially relevant to performing polymerase chain reactions using chemical denaturants as opposed to thermal cycling. | 2 |
RELATED PRIOR APPLICATIONS
This application claims priority under 35 U.S.C. §365(c) to International Application No. PCT/GB00/00116, filed on Jan. 18, 2000, which claims priority to British Application No. 9901586.9, filed on Jan. 25, 1999, both of which are incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates generally to a method for recovery of tin, tin alloys or lead alloys, such as solder, from printed circuit boards.
BACKGROUND OF THE INVENTION
With the advent of more and more electronic hardware, there is more and more electronic scrap produced, including scrap printed circuit boards. Furthermore, there is a growing need for more environmentally friendly methods of recycling scrap printed circuit boards. Many current commercial processes focus only on recovering some of the component parts of printed circuit boards. For example, printed circuit boards are heated in furnaces to pyrolyze the organic compounds and melt the metals. The plastics and the electronic components are destroyed producing potentially harmful fumes and a remaining complex mixture of metals that then needs to be separated. An alternative process comprises the selective removal of the higher value components, such as gold edge connectors and microprocessor chips, and then scrapping the rest of the printed circuit board to, for instance, landfill.
It is more likely than not that legislation will be planned and enacted, particularly in the European Community, that will require manufacturers of electronic equipment to take back equipment at the end of its useful life for recycling. There is, therefore, a need for a method for treating printed circuit boards that can recover the majority of the cornconent parts of scrap printed circuit boards without the production of undesirable waste products.
During the manufacture of printed circuit boards, solder is applied at various stages for the purpose of bonding components to the exposed areas of metal using a wave soldering technique or using a solder paste. Furthermore, during the formation of lines and pads on printed circuit boards, a layer of tin or a tin-lead alloy, such as solder, may be deposited by circuit boards, a layer of tin or a tin-lead alloy, such as solder, may be deposited by electrodeposition, immersion plating or other processes onto selected areas of copper surfaces of circuit boards to define conductive tracks, pads, through holes, etc., and to act as an etch resist during subsequent etching array of the copper surfaces. Thus, in a method for recycling of scrap printed circuit boards the selective dissolution of the tin or tin-lead alloy used in the manufacture of the printed circuit boards from the copper substrate surface, without dissolving the copper, is an important first step.
European Patent No. EP-0508960 discloses a method of producing metallic lead from a material containing lead by dissolving the lead contained in the material and an electrolysis step for the cathodic deposition of the dissolved lead. The dissolving step is carried out with the use of an acid electrolyte in the presence of a redox couple. The method is used, in particular, for the production of lead from the active material of spent accumulators. Although this process discloses the dissolution of lead, a process for the selective dissolution of tin or tin-lead alloys is still desired.
A new selective dissolution process has now been developed in which the Plastics associated with electronic components are not attacked, the electronic components are not affected by the oxidant solution used in the process and the identification coding on the electronic components is unaffected. Thus, the components can be recovered for use. Furthermore, the oxidant solution, which is used to dissolve the tin or tin-lead alloy, is regenerated and recycled to the method, thereby avoiding the production of undesirable or unwanted waste products.
SUMMARY OF THE INVENTION
Embodiments of the invention provide a method for selective dissolution of tin and/or lead or tin-containing alloys from printed circuit boards without substantial dissolution of copper or precious metals and without attack on plastics associated with electronic components mounted to printed circuit boards, the method comprising steps of:
(i) providing a solution comprising Ti(IV) and an acid which forms stable and soluble salt of Ti(III), Ti(IV), Sn(II) and Pb (II);
(ii) contacting a printed circuit board with the solution under anaerobic conditions for a time sufficient to effect dissolution of substantially all of the Sn and/or Pb- or Sn-containing alloy therefrom, as Sn(II) and/or Pb(II);
(iii) subjecting the solution from step (ii) to electrolytic reduction in order to recover substantially all of the Sn(II) and/or Pb(II) species contained therein as Sn and/or Pb; and
(iv) oxidizing the solution from step (iii) to regenerate the oxidant metal species and recycling the regenerated solution to step, (i) of the process.
By the term “soluble salt” as used herein is meant that the salt has a solubility of at least 1 gram per liter in the solution at the temperature at which the process is carried out.
For use in step (ii) of the method according to the invention, the oxidizing solution will preferably oxidize tin and lead metals, but will not dissolve copper. For this to be achieved the solution redox potential should be in the range of from +0.342 volts to ÷0.126 volts (standard hydrogen electrode), in terms of standard electrode potential, i.e. the interval between the anodic dissolution of copper and tin/lead.
The preferred solution for use in step (ii) of the method comprises an acid selected from the group consisting of fluoroboric acid, fluorosilicic acid, hexafluoro-phosphoric acid, hexafluoroantimonic acid and an alkylsulphonic acid. A solution comprising Ti(IV) and fluoroboric acid is particularly preferred. This solution may be prepared by dissolving Ti metal in fluoroboric acid with a sparge of oxygen gas or air. This solution has an unexpected selectivity for the dissolution of Sn and Pb over other metals, particularly copper.
In one embodiment of the method of the invention, other oxidant species/acids as defined in step (i) may also be used provided that, in use, the oxidant ions in solution have an oxidation potential which can selectively dissolve tin or a tin-lead alloy from the surface of the printed circuit board, but does not oxidize copper metal. Step (ii) of the method is carried out anaerobically, for example, by sparging the leach solution with an inert gas, such as nitrogen, during the leaching step.
The solution used in step (ii) of the method preferably comprises the oxidant metal species at a concentration generally in the range of from 0.01 M to 1.0 M metal ions, preferably 0.5 M to 0.9 M metal ion, and the acid at a concentration in the range of 10% to 100% by weight acid.
The temperature at which the solution used in step (ii) is contacted with the substrate surface is generally from 0° C. to 60° C., and preferably 20° C. to 30° C.
The method according to the invention may be used to dissolve tin or tin-lead alloys from printed circuit boards. Alloys which can be dissolved generally comprise from 5 to 99.5% by weight Sn, up to 95% by weight of Pb, and optionally up to 5% by weight of one or more of Ag, Bi, In, Zn, Cu or Sb. Solders commonly used in printed circuit board manufacture comprise 63% Sn, 37% Pb by weight, or 62% Sn, 36% Pb, 2% Ag by weight. Aluminium and any iron present in the printed circuit boards will dissolve in the acid leach and reduce the Ti(IV) oxidant to Ti(III), thus leaving less Ti(IV) available to react with the solder.
Accordingly, it is advantageous to remove these metals from the scrap printed circuit board prior to treatment with the leach solution. For example, physical separation methods may be used, such as by magnetic means for iron and using an eddy current separator for aluminium.
In step (iii) of the method of the invention, the electrolytic reduction of the solution containing the dissolved species is preferably carried out in a divided cell with inert electrodes, such as graphite anodes and stainless steel cathodes, and anolyte and catholyte compartments separated by a membrane, such as microporous or ion exchange material. The solution containing the dissolved species comprises the catholyte and the reaction at the cathode is the reduction of Sn(II) to Sn or the reduction of Sn(II) and Pb(II) to Sn and Pb, which are deposited on the cathode. When Pb and Sn are present together, for example as a solder alloy, they are then deposited together as an alloy, which can be re-used. The anolyte may comprise the same solution, or any other electrolyte of choice.
It is generally preferred for the catholyte solution to be isolated from the air since any oxygen present will oxidize Ti(III) in solution to Ti(IV), which in turn is reduced back to Ti(III) at the cathode. Furthermore, Sn(II) would be oxidized to Sn(IV) from which it is difficult to electrowin tin. Reduction of Ti(IV) to Ti(II) occurs at the expense of the metal plating reaction, leading to low metal yields and current efficiency.
The electrolytic reduction in step (iii) of the method of the invention is generally carried out at a current density in the range of from 50 A/m 2 to 500 A/m 2 . The electrowinning of the tin and/or lead in step (iii) is carried out until substantially all of the metals are electrowin. The reason for this is that any Sn(II) present in the solution during step (iv) of the process would be oxidized to Sn(IV). In this form, it is very difficult to electrowin tin metal as normally the preferred cathodic reaction would be the evolution of hydrogen.
The oxidation in step (iv) of the method of the invention may be carried out by the electrolytic oxidation of the solution from step (iii). The oxidation of Ti(III) to Ti(IV) is preferably carried out in a divided cell with inert electrodes and anolyte and catholyte compartments divided by a membrane separator, such as a cation exchange membrane, for example Nafion. The oxidation of Ti(II) to Ti(IV) takes place at the anode with the solution from step (iii) forming the anolyte. The catholyte may comprise the same solution, or any other electrolyte of choice. The solution treated according to step (iv) is thus regenerated and then is recycled to step (i) of the process. Both steps can advantageously be carried out in the same cell. The leach solution loaded with Sn and Pb is first electrolyzed as the catholyte where SnPb is plated onto the cathode. The metal depleted solution can then become the anolyte where Ti(III) is oxidized to Ti(IV) at the anode after as much tin as possible has been electrowin as solder at the cathode. This is because if any tin is still present when the solution is oxidized either with air/oxygen or electrochemically, then the Sn(II) species is converted to Sn(IV) ions. In the Sn(IV) form it is difficult to convert into the metal for the reasons as discussed above. However, alternatively two divided cells can be used.
In one embodiment of the method of the invention, the oxidation may be carried out by contacting the solution with air or oxygen gas, for example, by sparging the solution with oxygen or preferably with air at high sparge rates. Alternatively oxygen gas can conveniently be generated electrolytically at the anode of the divided cell used for plating Sn/Pb. This requires no extra energy and so would be cheaper than using bottled oxygen gas.
As previously stated, the method of the invention is particularly applicable to the removal of tin, and/or alloys containing lead and/or tin, from printed circuit boards and the subsequent removal and recovery of electronic components, such as transistors, capacitors and resistors, from printed circuit boards after treatment in accordance with the method of the invention. This is an important feature and advantage of the method of the invention because the electronic components are recovered in a functional state.
In one embodiment, the method of the invention further comprises a step of contacting the desoldered, and optionally component-stripped, printed circuit board with a copper leaching solution suitable for dissolving Cu for a time sufficient to effect dissolution of substantially all of the Cu from the printed circuit board. The copper leaching solution may comprise, for example, copper (II) chloride, sodium chloride and hydrochloric acid or an ammonium salt, ammonia and, optionally, Cu(II) ions, such as, for example with ammonium sulphate/ammonia, which is most preferred. The copper leaching step will generally be carried out at a temperature in the range of from 30° C. to 60° C., and preferably from 45° C. to 55° C. In the case of Cu(II) chloride leaching optionally the Cu(II) species present in the resulting leaching solution at the end of the dissolution step may be electrolytically reduced to copper. Also, some of the Cu(I) can be oxidized anodically back to Cu(II), for further leaching, either in a divided cell or with hydrogen peroxide.
Furthermore, prior to the copper leaching step, the printed circuit board may be comminuted by one or more mechanical processing steps. This is important for multilayer printed circuit boards which contain thin layers of copper sandwiched between layers of plastic laminate. For the copper leach solution to gain access to this metal, the boards can be shredded or broken up in some way to create small pieces in which the maximum distance of any copper metal to an external edge is less than 10 mm, and preferably less than 5 mm. In one embodiment, additional process steps may be included to further recover valuable components from the scrap printed circuit boards. The components may be sorted in order according to value of component, value of contained element or toxicity of contained element, and the decoppered plastic laminate could be treated further to recover any bromine that may be present from flame retarding additives.
After the copper leaching step, the residues will still contain all of the precious metals (if present originally). The precious metals may be recovered by methods well known in the art, such as, for example, leaching with cyanide to recover gold, or leaching with chlorine, including, for example, chlorine generated electrochemically. All of the precious metals can thus be separated from the residual plastics and ceramic materials.
DETAILED DESCRIPTION OF THE INVENTION
Illustrative embodiments of the method according to the invention are described below in further detail with reference to Examples 1-3.
EXAMPLE 1
1. Solder Leaching
A solution of Ti(IV) in fluoroboric acid was prepared by dissolving titanium metal sponge (22.84 g) in 42% fluoroboric acid (1.61) over a period of 20 hours with a sparge of nitrogen gas. The solution so-formed contained 0.3M titanium as Ti(IV). The rates of dissolution of a 63% Sn, 37% Pb solder and copper were compared by the following procedure.
The metals in the form of cylinders (25 mm diameter) were encapsulated by epoxy resin to leave only one flat end exposed. The exposed ends were rotated in the leach solution to eliminate diffusion effects and with an oxygen sparge to reoxidize reduced titanium species back to Ti(TV). The rates of dissolution of solder (63% Sn, 37% Pb) and of copper in fresh leach solutions, maintained at 60° C., were compared by analysis of the metals content of the solution over six hours. The results are given below in Table 1.
TABLE 1
Lead Dissolved
Tin Dissolved
Copper
Time
from Solder
from Solder
Dissolved
(minutes)
(g/l)
(g/l)
(g/l)
0
0
0
0
60
2.79
5.38
0.009
120
8.28
14.95
0.017
180
12.32
23.72
0.026
240
16.72
31.56
0.036
360
25.88
46.68
0.055
EXAMPLE 2
1. Solder Leaching
A leach solution was prepared with 7.2 g titanium metal dissolved in 1.51 concentrated fluoroboric acid (42%). This was then air sparged to oxidize the Ti ions to Ti(IV). Whole and segmented printed circuit boards were placed in this solution, which was sparged with nitrogen at 4 l/min. When all of the solder had dissolved from boards, they were removed and replaced with new ones. Table 2 below shows the build up of tin and lead in solution, as well as the concentration of iron and copper impurities.
TABLE 2
Time (hours)
Pb(g/l)
Sn(g/l)
Fe(g/l)
Cu(g/l)
0
0
0
0
0
4.25
3.9
7.5
0
0
8
6.0
10.8
0.02
0.01
12
9.8
16.1
0.05
0.02
16.25
14.2
25.3
0.14
0.01
20.25
18.2
31.9
0.21
0.03
24.5
20.2
35.1
0.41
0.01
30.5
25.7
43.0
0.58
0
2. Solder Electrowinning and Regeneration of Leach Solution
Tin and lead were recovered by electrowinning these metals from the fluoroborate solution.
The Ti(III) containing solution from step (i) above was regenerated by electrolysis. The anodic process was the oxidation of Ti(III) to Ti(IV) in order to regenerate active leachant for further leaching operations.
The electrolytic cell was constructed from PVC and consisted of separate anolyte and catholyte chambers divided by a membrane separator (cation selective ion exchange membrane). A graphite anode was placed in the anolyte compartment with a 316 stainless steel cathode in the catholyte compartment. The dimensions of each electrode were 90 mm×100 mm. The electrolysis was carried out with separate anolyte and catholyte solutions (each 1.0 liter), which was recirculated continuously from external tanks at flow rates of 60 l/h and 10 l/h, respectively. The low catholyte flow rate was chosen in order to minimize contact with air.
The catholyte solution consisted of 75% v/v of 40% w/w fluoroboric acid containing 0.1M titanium ions. The initial concentration of Sn was 38 g/l and the initial concentration of Pb was 32 g/l. The cell was operated at a current of 1.8A (200 Am 2 ) for a total of 11 hours. At the end of this time, the metal ion concentrations were reduced to 26 g/l Sn and 35 ppm Pb. The total weight of recovered metal was 28 g. The redox potential of the solution changed from −200 mV to −220 mV. The total current efficiency for Sn and Pb deposition was 83%.
During the electrolysis the redox value of the anolyte changed from −190 mV to +445 mV, which corresponds to the regeneration of the leachant with the Ti ion content converted to the higher (IV) oxidation state. The concentrations of Sn and Pb in this example of regenerated leachant were 2.6 g/l and 3.0 g/l, respectively.
The regenerated leachant was then used to dissolve further solder. The solution was divided into two equal portions of 370 ml. In one portion, a piece of scrap circuit board (area 50 mm×90 mm) with attached electrical components was immersed and rotated at approximately 250 rpm. After 8 hours at room temperature, 1.3 g of solder had been leached from the board and the components had either fallen off or could be removed easily by light brushing. The redox potential of the solution had fallen to −188 mV. The second sample was used to leach solder wire. After 18 hours the tin and lead concentrations had increased to 15.4 g and 9.6 g, respectively, with redox level of −214 mV. When leaching was continued for an additional 4 hours, the tin concentration only increased slightly to 16.1 g, and there was no further increase in the Pb concentration. The final redox potential was −246 mV.
3. Recovery of Components
Printed circuit boards were removed from a variety of pieces of electronic equipment, including an IBM personal computer, and treated with the solder leach solution, as described above. Most of the components were of the surface mount type and either dropped off or were removed by brushing the surface. Some components (chip capacitors and resistors) mounted on the underside were attached with adhesive as well as being soldered. After leaching, these components could be removed with minimal force.
The functionality of removed components was demonstrated with a 80486DX integrated circuit. After immersion in the sparged leach solution described above for three hours at 20° C., the functionality was tested by Intex Computers Ltd. and was found to have been unaffected.
4. Copper Leaching
A. A copper leaching solution was prepared from 0.3M copper (II) chloride, 4M sodium chloride and 0.4 M hydrochloric acid. 500 cm 3 of solution at 60° C. was used to leach 100.25 grams of desoldered printed circuit board with the components removed, as described above. The boards were shredded so that 80% of the pieces were less than 6 mm and 75% were greater than 2 mm. The boards were leached in the stirred solution for 4 hours. The copper concentration in the solution increased from 19 g Cu/l to 52.5 g Cu/l, which is suitable for electrowinning. The copper dissolved accounts for over 90% of the theoretical quantity of copper available and very little metal was visible attached to the laminate after the leaching step.
B. A leach solution was prepared containing 1.5M ammonium sulphate, 2M ammonia and 1 g copper/liter. 500 cm 3 of this solution was heated to 50° C. and stirred with 100 g of printed circuit board that had previously been desoldered, depopulated and shredded (as described above). The mixture was sparged with oxygen gas (up to 0.5 l/mm). After 180 minutes, almost no copper metal was visible in the remaining plastic laminate and the solution contained 25 g Cu/l. The small amount of gold that was present, however, was not dissolved.
EXAMPLE 3
Printed circuit boards were shredded to give a product with particles all less than about 12 mm. Magnetic material and aluminium were removed by Eriez Magrietics Ltd. (Bedws, South Wales) using an eddy current separator. This gave a product with reduced iron and aluminium contents.
Before Separation
After Separation
Iron
8.05%
0.04%
Aluminium
0.88%
0.18%
A solder leach solution (500 cc) was prepared by dissolving 18 grams of titanium sponge in 500 cc of 30% fluoroboric acid. When this solution had cooled, oxygen was sparged into it until the color changed from green, through brown to colorless. 260 grams of eddy current treated printed circuit board scrap was added to the 500 cc of leach solution and nitrogen was sparged through it to stir the mixture and to prevent oxidation by air of either any Ti(III) or Sn(II) in solution. Samples were taken periodically to monitor the progress of the reaction. The reaction was complete after 4 hours. Tin and lead concentrations were measured during the reaction.
Reaction Time
Tin Concentration
Lead Concentration
(minutes)
(g/l)
(g/l)
30
17.3
9.1
60
22.2
12.0
120
24.6
14.3
240
27.8
16.5
After 4 hours, most of the solder had dissolved and most of the Ti(IV) oxidant had been reduced to Ti(III).
A typical solution obtained by anaerobic leaching of printed circuit board scrap was used for electrowinning of the solder metal. This was carried out in a glass divided cell with a cathode current density of about 200 Am −2 for 6 hours. The catholyte was sparged with argon to prevent the formation of Sn(IV) and to stir the solution. The tin concentration dropped from 16 g/l to 0.16 g/l after 6 hours, and the lead concentration dropped from 12 g/l to 0.064 g/l after 6 hours. The total current efficiency for electrowinning of solder was 100%. The remaining catholyte was sparged with oxygen to regenerate the Ti(IV) for re-use.
After carrying out this process, the de-soldered printed circuit board can be leached to dissolve copper according to the method in Example 2, process B, as described above.
Having thus described at least one illustrative embodiment of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art. Such alterations, modifications and improvements are intended to be within the scope and spirit of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention's limit is defined only in the following claims and the equivalents thereto. | A method for selective dissolution of tin and/or lead- or tin-containing alloys from printed circuit boards is provided comprising contacting a printed circuit board with a solution comprising Ti(IV) and an acid which forms stable and soluble salt of Ti(III), Ti(IV), Sn(II) and Pb(II), under conditions to effect dissolution of substantially all of the Sn and/or Pb- or Sn-containing alloy therefrom, as Sn(II) and/or Pb(II) and recovering from the solution by electrolytic reduction substantially all of the Sn(II) and/or PB(II) species as Sn and/or Pb. After the electrolytic reduction step, the oxidant metal species is regenerated by oxidation and recycled to the first stage of the process. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This Application is a Divisional of and claims priority to U.S. application Ser. No. 11/836,555 filed Aug. 9, 2007 to Ronald D. Robertson and Wayne F. Schneider entitled “Dispenser For Viscous Condiments,” which issued as U.S. Pat. No. 8,146,781 on Apr. 3, 2012, the entire disclosure of which is hereby incorporated by reference to the extent permitted by law.
BACKGROUND OF INVENTION
The dispensing of viscous condiments, e.g., mustard, ketchup, mayonnaise, sandwich spreads and the like, is commonly done in restaurants. In order to handle the volume throughput requirements in restaurant kitchens, devices have been constructed for dispensing such condiments from tubes (packages) with the assistance of mechanical pump-type devices. Such devices are similar in construction to caulking guns. An example of such a device may be found in U.S. Pat. No. 4,830,231. While such devices have been effective, they do have some shortcomings.
It is desirable to eliminate material from the tubes that is not necessary. Even a small amount of material savings in a container can result in significant cost savings because of the large quantity required by restaurants, particularly in the fast food industry. However, to eliminate material, new assembly techniques may be needed necessitating new manufacturing equipment which adds again to the expense of the containers. Additionally, when viscous materials are contained in a container it is highly desirable to impede the migration of liquids such as water and lipids (fats) into the container material when such container material includes paperboard which can absorb and transfer such liquids by wicking. The absorption of such liquids can cause a detrimental appearance to the package and may even cause its unnecessary disposal. Typically, a condiment dispenser, such as that shown in the above-identified patent, was assembled using hot melt adhesives to join various container portions at the discharge end thereof. It would be desirable to reduce or eliminate this use of hot melt adhesive as a major element providing structural integrity to the package. Hot melt can cause detrimental generation of steam from moisture contained in various packaging components, particularly paperboard during assembly. The steam can cause problems such as forming tiny bubbles and/or holes through the hot melt thereby permitting oil and moisture to pass into raw edges of the paperboard tube. Thus, the tube (package) may become saturated, soften and begin to fall apart.
It is therefore desirable to provide an improved condiment dispenser. It is also desirable to provide an improved dispenser that has a reduction in the materials used and a reduction in the cost to manufacture.
SUMMARY OF INVENTION
The present invention relates to a container usable as a dispenser for use with viscous flowable condiments. The container includes a sidewall that is generally tubular forming a storage compartment for a viscous condiment. The sidewall has opposite ends, one of which is preferably open for receipt of a piston therein. The piston can be used to apply force to the condiment within the container to induce dispensing. The other end of the container is a normally closed end having a dispensing valve assembly. The dispensing valves are located on a valve plate secured to a mount plate which is secured to an inturned flange formed as part of the sidewall. The sidewall may be a convolute formed tube with a longitudinal seam. A removable membrane cover may be secured over the dispensing valve assembly which will provide a tamper-evident seal. The membrane cover is attached to the dispensing valve assembly before the valve assembly is attached to the sidewall. A die may be used to cut the perimeter shape of the membrane cover so that it precisely fits within an opening formed by the inturned flange. A portion of the membrane cover may be reverse bent to provide for gripping and subsequent removal of the cover. The dispensing valve assembly may be secured to the inturned generally flat flange and have an outer exposed edge portion engaging a hot melt material to cover all or substantially all of the exposed edge. Preferred materials for the sidewall and a portion of the dispensing valve assembly are paperboard and can have a polymer coating thereon to help effect resistance to penetration by liquids, and to help effect the joining of various components to one another as by heat sealing.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a side elevation view of a condiment dispenser shown partially in section and held by a dispensing gun in accordance with one embodiment of the present invention;
FIG. 2 is a fragmentary perspective view of the dispensing end of the condiment dispenser in accordance with one embodiment of the present invention;
FIG. 3 is a view similar to FIG. 2 but with a peel-off closure member covering the dispensing openings;
FIG. 4 is an enlarged fragmentary sectional view of the dispensing end of FIG. 3 in accordance with one embodiment of the present invention; and
FIG. 5 is a fragmentary top view of a web of covers that are partially die cut and interconnected together via their ears prior to their securement to a valve assembly in accordance with one embodiment of the present invention.
The same numbers used throughout the various figures designate like or similar parts and/or structure as described herein.
DETAILED DESCRIPTION
The reference numeral 1 designates generally a condiment dispenser for use in the storage and dispensing of viscous condiments 2 such as ketchup, mustard, mayonnaise, sandwich spread and the like. Such condiments 2 can be water and/or lipid based. In a preferred embodiment, the condiment dispenser 1 includes a feed device 3 that may be in the form of a trigger gun for use in applying force to a piston 4 which will in turn pressurize the condiment 2 for dispensing through a dispenser valve assembly 5 having one or more dispensing openings 6 . During dispensing, the piston 4 moves toward the valve assembly 5 . The feed device 3 can be manually operated for example by having a trigger or may be power operated for example by having an electric motor-driver actuator. Preferably, the feed device 3 is easily sanitized as by washing without detriment to the feed device.
The condiment dispenser 1 includes a sidewall 10 that may be formed of a polymeric-coated paperboard having a longitudinal seam 11 formed by overlapping edge margin portions 12 which may be secured together as by heat sealing of the polymeric coating. Preferably, the paperboard of the sidewall 10 has a thickness suitable to contain the condiment in storage and under dispensing pressure. The polymeric coating may be polyethylene or the like as are known in the art. Seam 11 may be formed as by heat sealing edge margins 12 as is also known in the art. The sidewall 10 has an inturned flange portion 14 which has a significant portion thereof generally perpendicular to the sidewall 10 and relatively flat. The flange 14 has an outer face 15 and an opening 16 which is defined by an internal edge 17 . The outer face 15 of the flange 14 is flush to slightly below flush with the free end 13 of the sidewall 10 , e.g. about 3/16 inch or less. Preferably the opening 16 is generally round as best seen in FIGS. 2 , 3 . When the flange 14 is formed, a plurality of pleats 18 may occur which can be easily accommodated by subsequent assembly steps as described below. The pleats 18 add rigidity to the flange 14 . Flange 14 may be formed by a roll forming process and may be held in its formed position by attachment to the valve assembly 5 .
The valve assembly 5 closes one end of the chamber 19 formed by sidewall 10 and is adapted for the selective release of condiment 2 from the chamber 19 . In the illustrated structure, the valve assembly 5 is secured in covering relation to the opening 16 and is preferably secured to an inside face 20 of the flange 14 . As shown in FIG. 4 , the valve assembly 5 includes a mount plate 21 in the form of an annular ring or disk having opposite side faces 22 , 23 , an outer perimeter edge 24 and an inner edge 25 defining a through opening 26 . Preferably, the opening 26 is in axial alignment with the opening 16 providing communication between the chamber 19 and the exterior of the dispenser 1 .
A slitted valve plate 31 is attached to the mount plate 21 preferably by securement to the face 22 . The valve plate 31 is preferably located on the interior side of the plate 21 . In a preferred embodiment, the valve plate 31 is in the form of a polymeric sheet, for example, low density polyethylene, having a plurality of the dispensing openings 6 in the form of die cut slits which can be in the form of an X for each opening. When the condiment 2 is pressurized by force applied to the piston 4 , flaps 32 formed by the X die cut slit will resiliently move outwardly allowing openings 6 to be exposed in the plate 31 for the condiment to flow through. During dispensing, the piston 4 moves along the chamber 19 toward the valve assembly 5 . When pressure is relieved, the flaps 32 move back to a closed or partially closed position. As shown, the plate 31 is secured to the face 22 as by heat bonding. In a preferred embodiment, the plate 21 is polymeric-coated paperboard element allowing heat bonding of the plate 21 to the flange 14 and to the valve plate 31 . The openings 6 are positioned inside or inwardly of the edge 25 . One or more openings 6 may be provided albeit four are shown in FIG. 2 .
As seen in FIG. 4 , the edge 24 of the plate 21 is sealed by a bead of hot melt 35 . Typically, during assembly of paperboard items, the paperboard will contain a certain amount of moisture. When the paperboard is heated, for example, during the application of hot melt or via the heat sealing process to join parts or areas together, the water in the paperboard will turn to steam and migrate out of the paperboard when possible. In the present invention, the openings 6 may be used as a steam vent should same be produced in the plate 21 during the application of hot melt as a caulking agent.
It should be pointed out that since plates 21 and 31 along with sidewall 10 , flange 14 and valve plate 31 all have polyethylene (or the like) coated surfaces, they can be heat welded together thereby eliminating the need for a hot melt to act as a structural component. Typically, when the paperboard elements are formed, they are die cut leaving “rough” edges that are uncoated. Such edges provide a means for ingress and egress of liquid vapor into the paperboard matrix. As best seen in FIG. 4 , a bead of hot melt 35 is applied proximate the edge 24 of plate 21 , the sidewall 10 , and flange 14 . It has been found that this hot melt functions primarily to seal the package and since the structural integrity is accomplished via the heat welding of the poly coated surfaces, rather than via hot melt, less hot melt is required and it may be of a less complex nature. Thus, the package is inherently stronger and less expensive to construct.
A cover 45 in the form of a membrane may be provided to selectively close the openings 6 for storage and shipping of the dispenser 1 . The cover 45 may be adhesively secured the outer surface 23 of plate 21 in overlying relation to the openings 6 . The cover 45 may be in the form of a polymeric-coated paper element or may be a polymeric material. It is preferred that the cover 45 be resistant to penetration by liquids. With the construction of the package as described above, when the hot melt is applied as shown and described with respect to FIG. 4 , the air tight seal between plate 21 and cover 45 closes off the escape route of steam to the outside. But for the construction of the present invention, the pressure of the steam would be high enough that it would pass through the hot melt rendering the hot melt caulking ineffective because oil and moisture then could pass into the raw edge 24 and saturate the paper and damage the integrity of the package. It is preferred that there be an air gap 26 a between at least a portion of the cover membrane 45 and the outer surface 46 of the valve disk 31 to provide for the release of steam should any be generated in the plate 21 during and shortly after the application of the hot melt 35 . This gap 26 a would allow for steam, if steam is generated, to move in the direction of the arrows 26 b and be discharged through the opening 6 into the chamber 19 . FIG. 4 shows the steam's path 26 b as it exits plate 21 . Steam can exit plate 21 through edge 25 . Upon exiting edge 25 of plate 21 , the steam enters air gap 26 a . Once the steam is in air gap 26 a , it can then exit into chamber 19 and the atmosphere through openings 6 .
As shown in FIG. 3 , the cover 45 has a plurality of circumferentially spaced ears 47 projecting from an outer perimeter 48 thereof. The cover 45 also includes a tab portion 50 having an ear 47 . FIG. 4 is a sectional view of FIG. 3 taken about line 4 - 4 . Therefore, neither the ears 47 nor the tab 50 are depicted in FIG. 4 . However, both the ears 47 and the tab 50 can be seen in FIG. 3 .
Preferably, during the manufacturing of valve assembly 5 , a plurality of covers 45 are included in a web made from a single piece of material. In the web, the covers 45 are partially die cut and interconnected together via their ears 47 . The valve assembly 5 may be appropriately aligned with a respective cover 45 in the web. Once the dispenser 1 is aligned with a cover 45 , the cover 45 may be bonded to the plate 21 . As shown, the bonding of the cover 45 to the plate 21 can take place in the annular ring area on surface 23 defined edges 17 and edge 25 . It will be appreciated by one skilled in the art that one bonding method includes heat bonding cover 45 to plate 21 . After the cover is bonded to the plate 21 , the final die cutting of the cover form the web can be accomplished by cutting the ears 47 . Once the ears 47 are cut, the cover 45 is completely detached from the web.
As mentioned above, the cover 45 has a tab portion 50 . Tab portion 50 provides the user a place to grip the cover 45 to assist in its removal from the valve assembly 5 . After the cover 45 is bonded to the valve assembly 5 , but before the valve assembly 5 is secured to sidewall 10 , tab portion 50 may be folded back toward the outer surface of cover 45 . The folding of tab portion 50 allows surface 23 of plate 21 to be directly mated to the inner face 20 of flange 14 without the tab portion 50 interfering. If tab portion 50 were not folded, it could extend into the seal created between surface 23 and face 20 . This could prevent the proper sealing of plate 21 to sidewall 10 . Additionally, it would prevent the cover 45 from being removed from the dispenser 1 because the tab portion 50 of cover 45 would be permanently sealed between surface 23 and face 20 . It will be appreciated by one skilled in the art that a tab portion 50 that is ¾″ long by ⅜″ wide is sufficient.
Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required.” Many changes, modifications, variations and other uses and applications of the present invention will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow. | A dispenser for viscous condiments including a tubular sidewall having opposite ends. One opposite end is open and can receive a plunger or piston therein for applying force to a condiment contained within the tubular sidewall. The other end of the sidewall includes a dispenser valve assembly including a member secured to an inturned flange portion of the sidewall with the flange portion being generally normal to the sidewall. The dispenser valve assembly is suitably secured to the flange portion as by heat sealing, such as a bead of hot melt, to form a composite laminated structure that is resistant to the penetration of liquid elements of the condiments. The dispenser valve assembly further includes a valve plate having one or more selectively openable discharge openings that will open and close under the influence of the pressure applied to the condiment in order to discharge the condiment. | 1 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. application Ser. No. 09/631,002 filed on Aug. 2, 2000.
FIELD OF THE INVENTION
[0002] The present invention relates to stents for use within a body passageway or duct which are particularly useful for repairing blood vessels narrowed or occluded by disease, and more particularly, to systems for delivering such stents.
BACKGROUND OF THE INVENTION
[0003] Various endoprosthesis assemblies, which include expandable stents, have been proposed or developed for use in association with angioplasty treatments and other medical procedures. The endoprosthesis assembly is percutaneously routed to a treatment site and the stent is expanded to maintain or restore the patency of a body passageway such as a blood vessel or bile duct. A stent is typically cylindrical in shape comprising an expandable open frame. The stent will typically expand either by itself (self-expanding stents) or will expand upon exertion of an outwardly directed radial force on an inner surface of the stent frame by a balloon catheter or the like.
[0004] Stents for endovascular implantation into a blood vessel or the like, to maintain or restore the patency of the passageway, have been deployed percutaneously to minimize the invasiveness associated with surgical exposure of the treatment site during coronary artery bypass. Percutaneous deployment is initiated by an incision into the vascular system of the patient, typically into the femoral artery. A tubular or sheath portion of an introducer is inserted through the incision and extends into the artery. The introducer has a central lumen which provides a passageway through the patient's skin and artery wall into the interior of the artery. An outwardly tapered hub portion of the introducer remains outside the patient's body to prevent blood from leaking out of the artery along the outside of the sheath. The introducer lumen includes a valve to block blood flow out of the artery through the introducer passageway. A distal end of a guide wire is passed through the introducer passageway into the patient's vasculature. The guide wire is threaded through the vasculature until the inserted distal end extends just beyond the treatment site. The proximal end of the guide wire extends outside the introducer.
[0005] For endovascular deployment, a stent, in an unexpanded or constricted configuration, is crimped onto a deflated balloon portion of a balloon catheter. The balloon portion is normally disposed near a distal end of the balloon catheter. The catheter has a central lumen extending its entire length. The distal end of the balloon catheter is threaded onto the proximal end of the guide wire. The distal end of the catheter is inserted into the introducer lumen and the catheter is pushed along the guide wire until the stent reaches the treatment site. At the treatment site, the balloon is inflated causing the stent to radially expand and assume an expanded configuration. When the stent is used to reinforce a portion of the blood vessel wall, the stent is expanded such that its outer diameter is approximately ten percent to twenty percent larger than the inner diameter of the blood vessel at the treatment site, effectively causing an interference fit between the stent and the blood vessel that inhibits migration of the stent. The balloon is deflated and the balloon catheter is withdrawn from the patient's body. The guide wire is similarly removed. Finally, the introducer is removed from the artery.
[0006] An example of a commonly used stent is given in U.S. Pat. No. 4,733,665 filed by Palmaz on Nov. 7, 1985. Such stents are often referred to as balloon expandable stents. Typically the stent is made from a solid tube of stainless steel. Thereafter, a series of cuts are made in the wall of the stent. The stent has a first smaller diameter which permits the stent to be delivered through the human vasculature by being crimped onto a balloon catheter. The stent also has a second or expanded diameter. The expanded diameter is achieved through the application, by the balloon catheter positioned in the interior of the tubular shaped member, of a radially outwardly directed force.
[0007] However, such “balloon expandable” stents are often impractical for use in some vessels such as superficial arteries, like the carotid artery. The carotid artery is easily accessible from the exterior of the human body. A patient having a balloon expandable stent made from stainless steel or the like, placed in their carotid artery might be susceptible to sever injury through day to day activity. A sufficient force placed on the patients neck, such as by falling, could cause the stent to collapse, resulting in injury to the patient. In order to prevent this, self-expanding stents have been proposed for use in such vessels. Self-expanding stents act similarly to springs and will recover to their expanded or implanted configuration after being crushed.
[0008] One type of self-expanding stent is disclosed in U.S. Pat. No. 4,665,771. The disclosed stent has a radially and axially flexible, elastic tubular body with a predetermined diameter that is variable under axial movement of ends of the body relative to each other and which is composed of a plurality of individually rigid but flexible and elastic thread elements defining a radially self-expanding helix. This type of stent is known in the art as a “braided stent” and is so designated herein. Placement of such stents in a body vessel can be achieved by a device which comprises an outer catheter for holding the stent at its distal end, and an inner piston which pushes the stent forward once it is in position.
[0009] Other types of self-expanding stents use alloys such as Nitinol (Ni—Ti alloy) which have shape memory and/or superelastic characteristics in medical devices which are designed to be inserted into a patient's body. The shape memory characteristics allow the devices to be deformed to facilitate their insertion into a body lumen or cavity and then be heated within the body so that the device returns to its original shape. Superelastic characteristics on the other hand generally allow the metal to be deformed and restrained in the deformed condition to facilitate the insertion of the medical device containing the metal into a patient's body, with such deformation causing the phase transformation. Once within the body lumen the restraint on the superelastic member can be removed, thereby reducing the stress therein so that the superelastic member can return to its original un-deformed shape by the transformation back to the original phase.
[0010] Alloys having shape memory/superelastic characteristics generally have at least two phases. These phases are a martensite phase, which has a relatively low tensile strength and which is stable at relatively low temperatures, and an austenite phase, which has a relatively high tensile strength and which is stable at temperatures higher than the martensite phase.
[0011] When stress is applied to a specimen of a metal such as Nitinol exhibiting superelastic characteristics at a temperature above which the austenite is stable (i.e. the temperature at which the transformation of martensite phase to the austenite phase is complete), the specimen deforms elastically until it reaches a particular stress level where the alloy then undergoes a stress-induced phase transformation from the austenite phase to the martensite phase. As the phase transformation proceeds, the alloy undergoes significant increases in strain but with little or no corresponding increases in stress. The strain increases while the stress remains essentially constant until the transformation of the austenite phase to the martensite phase is complete. Thereafter, further increase in stress is necessary to cause further deformation. The martensitic metal first deforms elastically upon the application of additional stress and then plastically with permanent residual deformation.
[0012] If the load on the specimen is removed before any permanent deformation has occurred, the martensitic specimen will elastically recover and transform back to the austenite phase. The reduction in stress first causes a decrease in strain. As stress reduction reaches the level at which the martensite phase transforms back into the austenite phase, the stress level in the specimen will remain essentially constant (but substantially less than the constant stress level at which the austenite transforms to the martensite) until the transformation back to the austenite phase is complete, i.e. there is significant recovery in strain with only negligible corresponding stress reduction. After the transformation back to austenite is complete, further stress reduction results in elastic strain reduction. This ability to incur significant strain at relatively constant stress upon the application of a load and to recover from the deformation upon the removal of the load is commonly referred to as superelasticity or pseudoelasticity. It is this property of the material which makes it useful in manufacturing tube cut self-expanding stents. The prior art makes reference to the use of metal alloys having superelastic characteristics in medical devices which are intended to be inserted or otherwise used within a patient's body. See for example, U.S. Pat. No. 4,665,905 to Jervis and U.S. Pat. No. 4,925,445 to Sakamoto et al.
[0013] Designing delivery systems for delivering self-expanding stents has proven difficult. One example of a prior art self-expanding stent delivery system is shown in U.S. Pat. No. 4,580,568 to Gianturco. This patent discloses a delivery apparatus which uses a hollow sheath, like a catheter. The sheath is inserted into a body vessel and navigated therethrough so that its distal end is adjacent the target site. The stent is then compressed to a smaller diameter and loaded into the sheath at the sheath's proximal end. A cylindrical flat end pusher, having a diameter almost equal to the inside diameter of the sheath is inserted into the sheath behind the stent. The pusher is then used to push the stent from the proximal end of the sheath to the distal end of the sheath. Once the stent is at the distal end of the sheath, the sheath is pulled back, while the pusher remain stationary, thereby exposing the stent and expanding it within the vessel.
[0014] However, delivering the stent through the entire length of the catheter may cause many problems, including possible damage to a vessel or the stent during its travel. In addition, it is often difficult to design a pusher having enough flexibility to navigate through the catheter, but also enough stiffness to push the stent out of the catheter. Therefore, it was determined that pre-loading the stent into the distal and of the catheter, and then delivering the catheter through the vessel to the target site may be a better approach. In order to ensure proper placement of the stent within catheter, it is often preferred that the stent be pre-loaded at the manufacturing site. Except this in itself has posed some problems. Because the catheter exerts a significant force on the self-expanding stent which keeps it from expanding, the stent may tend to become imbedded within the wall of the catheter. When this happens, the catheter has difficulty sliding over the stent during delivery. This situation can result in the stent becoming stuck inside the catheter, or could damage the stent during delivery.
[0015] Another example of a prior art self-expanding stent delivery system is given in U.S. Pat. No. 4,732,152 to Wallsten et al. This patent discloses a probe or catheter having a self-expanding stent pre-loaded into its distal end. The stent is first placed within a flexible hose and compressed before it is loaded into the catheter. When the stent is at the delivery site the catheter and hose are withdrawn over the stent so that it can expand within the vessel. However, withdrawing the flexible hose over the stent during expansion could also cause damage to the stent.
[0016] An example of a more preferred self-expanding stent delivery system can be found in U.S. Pat. No. 6,019,778 to Wilson et al. and issued on Feb. 1, 2000, which is hereby incorporated herein by reference. While using such a device, it is essential for the stent delivery device to be able to navigate through tortuous vessels, lesions and previously deployed devices (stents). The delivery system must follow a guide wire with out overpowering the wire in the tortuous vessels. The guidewire, when entering a new path, needs to be flexible enough to bend such that it is angled with respect to the delivery device proximal thereto. Because the guidewire extends through the distal end of the delivery device, if the distal end of the delivery device is stiff, it will not bend with the guidewire and may prolapse the wire causing the guidewire to move its position to align itself with the distal end of the delivery device. This could cause difficulty in navigating the delivery system, and may also cause any debris dislodged during the procedure to flow upstream and cause a stroke.
[0017] Therefore, there has been a need for a self-expanding stent delivery system which better navigates tortuous passageways, and more easily and accurately deploys the stent within the target area. The present invention provides such a delivery device.
SUMMARY OF THE INVENTION
[0018] The present invention overcomes the disadvantages associated with self-expanding stent deployment as briefly described above.
[0019] In accordance with one aspect, the present invention is directed to a delivery apparatus for a self-expanding stent. The delivery apparatus comprises a substantially tubular shaft having a proximal end, a distal end, a guidewire lumen extending between the proximal and distal ends, and a stent bed proximate the distal end upon which the self-expanding stent is positioned. The delivery apparatus further comprises a substantially tubular sheath defining an interior volume. The sheath has a proximal end, a distal end, and an enlarged section proximate the distal end. The sheath being coaxially positioned over the shaft such that the enlarged section is aligned with the stent bed. The sheath being formed from an inner polymeric layer, an outer polymeric layer, and a flat wire reinforcement layer.
[0020] In accordance with another aspect, the present invention is directed to a delivery apparatus for a self-expanding stent. The delivery apparatus comprises a shaft having a proximal end, a distal end, a guidewire lumen extending between the proximal and distal ends, and a stent bed proximate the distal end upon which the stent is mounted. The delivery apparatus also comprises a sheath defining an interior volume. The sheath having a proximal end, a distal end, and an enlarged section proximate the distal end. The sheath being coaxially positioned over the shaft such that the enlarged section is aligned with the stent bed. The sheath is formed from an inner polymeric layer, a lubricious coating on the inner polymeric layer, an outer polymeric layer, and a flat wire reinforcement layer.
[0021] The delivery apparatus for a self-expanding stent of the present invention utilizes a sheath constructed in a manner that allows flexibility in navigating through tortuous vessels, provides pushability for navigating through tight passageways, and substantially prevents the stent from becoming embedded in the device. The apparatus utilizes a sheath constructed from two polymeric layers and a reinforcement layer sandwiched therebetween. The reinforcement layer is formed from flat metallic wire to ensure adequate strength with reduced profile.
BRIEF DESCRIPTION OF DRAWINGS
[0022] The foregoing and other 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.
[0023] [0023]FIG. 1 is a simplified elevational view of a stent delivery apparatus made in accordance with the present invention.
[0024] [0024]FIG. 2 is a view similar to that of FIG. 1 but showing an enlarged view of the distal end of the apparatus having a section cut away to show the stent loaded therein.
[0025] [0025]FIG. 3 is a simplified elevational view of the distal end of the inner shaft made in accordance with the present invention.
[0026] [0026]FIG. 4 is a cross-sectional view of FIG. 3 taken along lines 4 - 4 .
[0027] [0027]FIGS. 5 through 9 are partial cross-sectional views of the apparatus of the present invention sequentially showing the deployment of the self-expanding stent within the vasculature.
[0028] [0028]FIG. 10 is a simplified elevational view of a shaft for a stent delivery apparatus made in accordance with the present invention.
[0029] [0029]FIG. 11 is a partial cross-sectional view of the shaft and sheath of the stent delivery apparatus in accordance with the present invention.
[0030] [0030]FIG. 12 is a partial cross-sectional view of the shaft and modified sheath of the stent delivery system in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] [0031]FIGS. 1 and 2 illustrate a self-expanding stent delivery apparatus 10 made in accordance with the present invention. Apparatus 10 comprises inner and outer coaxial tubes. The inner tube is called the shaft 12 and the outer tube is called the sheath 14 . A self-expanding stent 100 is located within the sheath 14 , wherein the stent 100 makes frictional contact with the sheath 14 and the shaft 12 is disposed coaxially within a lumen of the stent 100 .
[0032] Shaft 12 has proximal and distal ends 16 and 18 respectively. The proximal end 16 of the shaft 12 has a Luer guidewire hub 20 attached thereto. As seen best from FIG. 10, the proximal end 16 of the shaft 12 is preferably a ground stainless steel hypotube. In one exemplary embodiment, the hypotube is stainless steel and has a 0.042 inch outside diameter at its proximal end and then tapers to a 0.036 inch outside diameter at its distal end. The inside diameter of the hypotube is 0.032 inch throughout its length. The tapered outside diameter is to gradually change the stiffness of the hypotube along its length. This change in the hypotube stiffness allows for a more rigid proximal end or handle end that is needed during stent deployment. If the proximal end is not stiff enough, the hypotube section extending beyond the Tuohy Borst valve described below could buckle as the deployment forces are transmitted. The distal end of the hypotube is more flexible allowing for better track-ability in tortuous vessels. The distal end of the hypotube also needs to be flexible to minimize the transition between the hypotube and the coil section described below.
[0033] As will be described in greater detail below, shaft 12 has a body portion 22 , wherein at least a section thereof is made from a flexible coiled member 24 , looking very much like a compressed or closed coil spring. Shaft 12 also includes a distal portion 26 , distal to body portion 22 , which is preferably made from a coextrusion of high-density polyethylene and nylon. The two portions 22 and 26 are joined together by any number of means known to those of ordinary skill in the art including heat fusing, adhesive bonding, chemical bonding or mechanical attachment.
[0034] As best seen from FIG. 3, the distal portion 26 of the shaft 12 has a distal tip 28 attached thereto. Distal tip 28 may be made from any number of suitable materials known in the art including polyamide, polyurethane, polytetrafluoroethylene, and polyethylene including multi-layer or single layer construction. The distal tip 28 has a proximal end 30 whose diameter is substantially the same as the outer diameter of the sheath 14 which is immediately adjacent thereto. The distal tip 28 tapers to a smaller diameter from its proximal end 30 to its distal end 32 , wherein the distal end 32 of the distal tip 28 has a diameter smaller than the inner diameter of the sheath 14 .
[0035] The stent delivery apparatus 10 glides over a guide wire 200 (shown in FIG. 1) during navigation to the stent deployment site. As used herein, guidewire can also refer to similar guiding devices which have a distal protection apparatus incorporated herein. One preferred distal protection device is disclosed in published PCT Application 98/33443, having an international filing date of Feb. 3, 1998. As discussed above, if the distal tip 28 is too stiff it will overpower the guide wire path and push the guide wire 200 against the lumen wall and in some very tortuous settings the stent delivery apparatus 10 could prolapse the wire. Overpowering of the wire and pushing of the apparatus against the lumen wall can prevent the device from reaching the target area because the guide wire will no longer be directing the device. Also as the apparatus is advanced and pushed against the lumen wall debris from the lesion can be dislodged and travel upstream causing complications to distal vessel lumens. The distal tip 28 is designed with an extremely flexible leading edge and a gradual transition to a less flexible portion. The distal tip 28 may be hollow and may be made of any number of suitable materials, including 40D nylon. Its flexibility may be changed by gradually increasing the thickness of its cross-sectional diameter, whereby the diameter is thinnest at its distal end, and is thickest at its proximal end. That is, the cross-sectional diameter and wall thickness of the distal tip 28 increases as you move in the proximal direction. This gives the distal end 32 of the distal tip 28 the ability to be directed by the guidewire prior to the larger diameter and thicker wall thickness (less flexible portion) of the distal tip 28 over-powering the guidewire. Over-powering the wire, as stated above, is when the apparatus (due to its stiffness) dictates the direction of the device instead of following the wire.
[0036] The guidewire lumen 34 has a diameter that is matched to hug the recommended size guide wire so that there is a slight frictional engagement between the guidewire 200 and the guidewire lumen 34 of distal tip 28 . The distal tip 28 then has a rounded section 36 between its distal portion 32 and its proximal portion 30 . This helps prevent the sheath 14 from slipping distally over the distal tip 28 , and thereby exposing the squared edges of the sheath 14 to the vessel, which could cause damage thereto. This improves the device's “pushability.” As the distal tip 28 encounters resistance it does not allow the sheath 14 to ride over it thereby exposing the sheath's 14 square cut edge. Instead the sheath 14 contacts the rounded section 36 of the distal tip 28 and thus transmits the forces applied to the distal tip 28 . The distal tip 28 also has a proximally tapered section 38 which helps guide the distal tip 28 through the deployed stent 100 without providing a sharp edge that could grab or hang up on a stent strut end or other irregularity in the lumen inner diameter.
[0037] Attached to distal portion 26 of shaft 12 is a stop 40 , which is proximal to the distal tip 28 and stent 100 . Stop 40 may be made from any number of suitable materials known in the art, including stainless steel, and is even more preferably made from a highly radio-opaque material such as platinum, gold tantalum, or radio-opaque filled polymer. The stop 40 may be attached to shaft 12 by any suitable means, including mechanical or adhesive bonding, or by any other means known to those skilled in the art. Preferably, the diameter of stop 40 is large enough to make sufficient contact with the loaded stent 100 without making frictional contact with the sheath 14 . As will be explained subsequently, stop 40 helps to “push” the stent 100 or maintain its relative position during deployment, by preventing the stent 100 from migrating proximally within the sheath 14 during retraction of the sheath 14 for stent deployment. The radio-opaque stop 40 also aides in positioning the stent 100 within the target lesion during deployment within a vessel, as is described below.
[0038] A stent bed 42 is defined as being that portion of the shaft 12 between the distal tip 28 and the stop 40 (FIG. 2). The stent bed 42 and the stent 100 are coaxial so that the distal portion 26 of the shaft 12 comprising the stent bed 42 is located within the lumen of stent 100 . The stent bed 42 makes minimal contact with stent 100 because of the space which exists between the shaft 12 and the sheath 14 . As the stent 100 is subjected to temperatures at the austenite phase transformation it attempts to recover to its programmed shape by moving outwardly in a radial direction within the sheath 14 . The sheath 14 constrains the stent 100 as will be explained in detail subsequently. Distal to the distal end of the loaded stent 100 attached to the shaft 12 is a radio-opaque marker 44 which may be made of platinum, iridium coated platinum, gold tantalum, stainless steel, radio-opaque filled polymer or any other suitable material known in the art.
[0039] As seen from FIGS. 2, 3 and 10 , the body portion 22 of shaft 12 is made from a flexible coiled member 24 , similar to a closed coil or compressed spring. During deployment of the stent 100 , the transmission of compressive forces from the stop 40 to the Luer guidewire hub 20 is an important factor in deployment accuracy. A more compressive shaft 12 results in a less accurate deployment because the compression of the shaft 12 is not taken into account when visualizing the stent 100 under fluoroscopic imaging. However, a less compressive shaft 12 usually means less flexibility, which would reduce the ability of the apparatus 10 to navigate through tortuous vessels. A coiled assembly allows both flexibility and resistance to compression. When the apparatus 10 is navigating through the arteries, the shaft 12 is not in compression and therefore the coiled member 24 is free to bend with the delivery path. As one deploys the stent 100 , tension is applied to the sheath 14 as the sheath 14 is retracted over the encapsulated stent 100 . Because the stent 100 is self-expanding it is in contact with the sheath 14 and the forces are transferred along the stent 100 and to the stop 40 of the shaft 12 . This results in the shaft 12 being under compressive forces. When this happens, the flexible coiled member 24 (no gaps between the coil members) transfers the compressive force from one coil to the next.
[0040] The flexible coiled member 24 further includes a covering 46 that fits over the flexible coiled member 24 to help resist buckling of the coiled member 24 in both bending and compressive modes. The covering 46 is an extruded polymer tube and is preferably a soft material that can elongate slightly to accommodate bending of the flexible coiled member 24 , but does not allow the coils to ride over each other. Covering 46 may be made from any number of suitable materials including coextrusions of Nylon® and high-density polyethylene, polyurethane, polyamide, polytetrafluoroethylene, etc. The extrusion is also attached to the stop 40 . Flexible coiled member 24 may be made of any number of materials known in the art including stainless steel, Nitinol, rigid polymers. In one exemplary embodiment, flexible coiled member 24 is made from a 0.003 inch thick by 0.010 inch wide stainless steel ribbon wire. The wire may be round, or more preferably flat to reduce the profile of the flexible coiled member 24 .
[0041] Sheath 14 is preferably a polymeric catheter and has a proximal end 48 terminating at a sheath hub 50 (FIG. 1). Sheath 14 also has a distal end 52 which terminates at the proximal end 30 of distal tip 28 of the shaft 12 , when the stent 100 is in an un-deployed position as shown in FIG. 2. The distal end 52 of sheath 14 includes a radio-opaque marker band 54 disposed along its outer surface (FIG. 1). As will be explained below, the stent 100 is fully deployed when the marker band 54 is proximal to radio-opaque stop 40 , thus indicating to the physician that it is now safe to remove the delivery apparatus 10 from the body.
[0042] As detailed in FIG. 2, the distal end 52 of sheath 14 includes an enlarged section 56 . Enlarged section 56 has larger inside and outside diameters than the inside and outside diameters of the sheath 14 proximal to enlarged section 56 . Enlarged section 56 houses the pre-loaded stent 100 , the stop 40 and the stent bed 42 . The outer sheath 14 tapers proximally at the proximal end of enlarged section 56 to a smaller size diameter. This design is more fully set forth in co-pending U.S. application Ser. No. 09/243,750 filed on Feb. 3, 1999, which is hereby incorporated herein by reference. One particular advantage to the reduction in the size of the outer diameter of sheath 14 proximal to enlarged section 56 is in an increase in the clearance between the delivery apparatus 10 and the guiding catheter or sheath that the delivery apparatus 10 is placed through. Using fluoroscopy, the physician will view an image of the target site within the vessel, before and after deployment of the stent, by injecting a radio-opaque solution through the guiding catheter or sheath with the delivery apparatus 10 placed within the guiding catheter. Because the clearance between the sheath 14 , and the guiding catheter is increased by tapering or reducing the outer diameter of the sheath 14 proximal to enlarged section 56 , higher injection rates may be achieved, resulting in better images of the target site for the physician. The tapering of sheath 14 provides higher injection rates of radio-opaque fluid, both before and after deployment of the stent.
[0043] A problem encountered with earlier self-expanding stent delivery systems is that of the stent becoming embedded within the sheath in which it is disposed. Referring to FIG. 11, there is illustrated a sheath construction which may be effectively utilized to substantially prevent the stent from becoming embedded in the sheath as well as provide other benefits as described in detail below. As illustrated, the sheath 14 comprises a composite structure of at least two layers and preferably three layers. The outer layer 60 may be formed from any suitable biocompatible material. Preferably, the outer layer 60 is formed from a lubricious material for ease of insertion and removal of the sheath 14 . In a preferred embodiment, the outer layer 60 comprises a polymeric material such as Nylon®. The inner layer 62 may also be formed from any suitable biocompatible material. For example, the inner layer 62 may be formed from any number of polymers including polyethylene, polyamide or polytetrafluroethylene. In a preferred embodiment, the inner layer 62 comprises polytetrafluroethylene. Polytetrafluroethylene is also a lubricious material which makes stent delivery easier, thereby preventing damage to the stent 100 . The inner layer 62 may also be coated with another material to increase the lubricity thereof for facilitating stent deployment. Any number of suitable biocompatible materials may be utilized. In an exemplary embodiment, silicone based coatings may be utilized. Essentially, a solution of the silicone based coating may be injected through the apparatus and allowed to cure at room temperature. The amount of silicone based coating utilized should be minimized to prevent transference of the coating to the stent 100 . Sandwiched between the outer and inner layers 60 and 62 , respectively, is a wire reinforcement layer 64 . The wire reinforcement layer 64 may take on any number of configurations. In the exemplary embodiment, the wire reinforcement layer 64 comprises a simple under and over weave or braiding pattern. The wire used to form the wire reinforcement layer 64 may comprise any suitable material and any suitable cross-sectional shape. In the illustrated exemplary embodiment, the wire forming the wire reinforcement layer 64 comprises stainless steel and has a substantially circular cross-section. In order to function for its intended purpose, as described in detail below, the wire has a diameter of 0.002 inches.
[0044] The three layers 60 , 62 , and 64 comprising the sheath 14 collectively enhance stent deployment. The outer layer 60 facilitates insertion and removal of the entire apparatus 10 . The inner layer 62 and the wire reinforcement layer 64 function to prevent the stent 100 from becoming embedded in the sheath 14 . Self-expanding stents such as the stent 100 of the present invention tend to expand to their programmed diameter at a given temperature. As the stent attempts to undergo expansion, it exerts radially outward directed forces and may become embedded in the sheath 14 restraining it from expanding. Accordingly, the wire reinforcing layer 64 provides radial or hoop strength to the inner layer 62 thereby creating sufficient resistance to the outwardly directed radial force of the stent 100 within the sheath 14 . The inner layer 62 , also as discussed above, provides a lower coefficient of friction surface to reduce the forces required to deploy the stent 100 (typically in the range from about five to eight pounds). The wire reinforcement layer 64 also provides tensile strength to the sheath 14 . In other words, the wire reinforcement layer 64 provides the sheath 14 with better pushability, i.e., the ability to transmit a force applied by the physician at a proximal location on the sheath 14 to the distal tip 28 , which aids in navigation across tight stenotic lesions within the vasculature. Wire reinforcement layer 64 also provides the sheath 14 with better resistance to elongation and necking as a result of tensile loading during sheath retraction for stent deployment.
[0045] The sheath 14 may comprise all three layers along its entire length or only in certain sections, for example, along the length of the stent 100 . In a preferred embodiment, the sheath 14 comprises all three layers along its entire length.
[0046] Prior art self-expanding stent delivery systems did not utilize wire reinforcement layers. Because the size of typical self-expanding stents is large, as compared to balloon expandable coronary stents, the diameter or profile of the delivery devices therefor had to be large as well. However, it is always advantageous to have delivery systems which are as small as possible. This is desirable so that the devices can reach into smaller vessels and so that less trauma is caused to the patient. However, as stated above, the advantages of a thin reinforcing layer in a stent delivery apparatus outweighs the disadvantages of slightly increased profile.
[0047] In order to minimize the impact of the wire reinforcement layer on the profile of the apparatus 10 , the configuration of the wire reinforcement layer 64 may be modified. For example, this may be accomplished in a number of ways, including changing the pitch of the braid, changing the shape of the wire, changing the wire diameter and/or changing the number of wires utilized. In a preferred embodiment, the wire utilized to form the wire reinforcement layer comprises a substantially rectangular cross-section as illustrated in FIG. 12. In utilizing a substantially rectangular cross-section wire, the strength features of the reinforcement layer 64 may be maintained with a significant reduction in the profile of the delivery apparatus. In this preferred embodiment, the rectangular cross-section wire has a width of 0.003 inches and a height of 0.001 inches. Accordingly, braiding the wire in a similar manner to FIG. 11, results in a fifty percent decrease in the thickness of the wire reinforcement layer 64 while maintaining the same beneficial characteristics as the 0.002 round wire. The flat VVire may comprise any suitable material, and preferably comprises stainless steel.
[0048] [0048]FIGS. 1 and 2 show the stent 100 as being in its fully un-deployed position. This is the position the stent is in when the apparatus 10 is inserted into the vasculature and its distal end is navigated to a target site. Stent 100 is disposed around the stent bed 42 and at the distal end 52 of sheath 14 . The distal tip 28 of the shaft 12 is distal to the distal end 52 of the sheath 14 . The stent 100 is in a compressed state and makes frictional contact with the inner surface of the sheath 14 .
[0049] When being inserted into a patient, sheath 14 and shaft 12 are locked together at their proximal ends by a Tuohy Borst valve 58 . This prevents any sliding movement between the shaft 12 and sheath 14 , which could result in a premature deployment or partial deployment of the stent 100 . When the stent 100 reaches its target site and is ready for deployment, the Tuohy Borst valve 58 is opened so that the sheath 14 and shaft 12 are no longer locked together.
[0050] The method under which delivery apparatus 10 deploys stent 100 may best be described by referring to FIGS. 5 - 9 . In FIG. 5, the delivery apparatus 10 has been inserted into a vessel 300 so that the stent bed 42 is at a target diseased site. Once the physician determines that the radio-opaque marker band 54 and stop 40 on shaft 12 indicating the ends of stent 100 are sufficiently placed about the target disease site, the physician would open Tuohy Borst valve 58 . The physician would then grasp the Luer guidewire hub 20 of shaft 12 so as to hold shaft 12 in a fixed position. Thereafter, the physician would grasp the Tuohy Borst valve 58 , attached proximally to sheath 14 , and slide it proximal, relative to the shaft 12 as shown in FIGS. 6 and 7. Stop 40 prevents the stent 100 from sliding back with sheath 14 , so that as the sheath 14 is moved back, the stent 100 is effectively “pushed” out of the distal end 52 of the sheath 14 , or held in position relative to the target site. Stent 100 should be deployed in a distal to proximal direction to minimize the potential for creating emboli with the diseased vessel 300 . Stent deployment is complete when the radio-opaque band 54 on the sheath 14 is proximal to radio-opaque stop 40 , as shown in FIG. 8. The apparatus 10 can now be withdrawn through stent 100 and removed from the patient.
[0051] [0051]FIGS. 2 and 9 show a preferred embodiment of a stent 100 , which may be used in conjunction with the present invention. Stent 100 is shown in its unexpanded compressed state, before it is deployed, in FIG. 2. Stent 100 is preferably made from a superelastic alloy such as Nitinol. Most preferably, the stent 100 is made from an alloy comprising from about 50.5 percent (as used herein these percentages refer to atomic percentages) Ni to about 60 percent Ni, and most preferably about 55 percent Ni, with the remainder of the alloy Ti. Preferably, the stent 100 is such that it is superelastic at body temperature, and preferably has an Af in the range from about twenty-one degrees C to about thirty-seven degrees C. The superelastic design of the stent makes it crush recoverable which, as discussed above, can be used as a stent or frame for any number of vascular devices for different applications.
[0052] Stent 100 is a tubular member having front and back open ends a longitudinal axis extending there between. The tubular member has a first smaller diameter, FIG. 2, for insertion into a patient and navigation through the vessels, and a second larger diameter for deployment into the target area of a vessel. The tubular member is made from a plurality of adjacent hoops 102 extending between the front and back ends. The hoops 102 include a plurality of longitudinal struts 104 and a plurality of loops 106 connecting adjacent struts, wherein adjacent struts are connected at opposite ends so as to form a substantially S or Z shape pattern. Stent 100 further includes a plurality of curved bridges 108 , which connect adjacent hoops 102 . Bridges 108 connect adjacent struts together at bridge to loop connection points which are offset from the center of a loop.
[0053] The above described geometry helps to better distribute strain throughout the stent, prevents metal to metal contact when the stent is bent, and minimizes the opening size between the features, struts, loops and bridges. The number of and nature of the design of the struts, loops and bridges are important factors when determining the working properties and fatigue life properties of the stent. Preferably, each hoop has between twenty-four to thirty-six or more struts. Preferably the stent has a ratio of number of struts per hoop to strut length (in inches) which is greater than two hundred. The length of a strut is measured in its compressed state parallel to the longitudinal axis of the stent.
[0054] In trying to minimize the maximum strain experienced by features, the stent utilizes structural geometries which distribute strain to areas of the stent which are less susceptible to failure than others. For example, one vulnerable area of the stent is the inside radius of the connecting loops. The connecting loops undergo the most deformation of all the stent features. The inside radius of the loop would normally be the area with the highest level of strain on the stent. This area is also critical in that it is usually the smallest radius on the stent. Stress concentrations are generally controlled or minimized by maintaining the largest radii possible. Similarly, we want to minimize local strain concentrations on the bridge and bridge to loop connection points. One way to accomplish this is to utilize the largest possible radii while maintaining feature widths which are consistent with applied forces. Another consideration is to minimize the maximum open area of the stent. Efficient utilization of the original tube from which the stent is cut increases stent strength and it's ability to trap embolic material.
[0055] Although shown and described is what is believed to be the most practical and preferred embodiments, it is apparent that departures from specific designs and methods described and shown will suggest themselves to those skilled in the art and may be used without departing from the spirit and scope of the invention. The present invention is not restricted to the particular constructions described and illustrated, but should be constructed to cohere with all modifications that may fall within the scope of the appended claims. | A self-expanding stent delivery apparatus having a reinforced sheath for the safe, effective and accurate deployment of self-expanding stents. The sheath is formed from an inner polymeric layer, an outer polymeric layer and a reinforcement layer sandwiched therebetween. The reinforcement layer comprises flat metallic wire to provide the requisite radial and axial strength. In addition, flat wire reduces the profile of the device. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Pursuant to 35 U.S.C. §366, this application claims the benefit of PCT patent application PCT/US2012/028140, filed Mar. 7, 2012, the entirety of which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present disclosure relates generally to dental implements and, more particularly, to flavored toothpicks and a method for making the same.
BACKGROUND OF THE INVENTION
[0003] Toothpicks have been used as a dental implement by man for centuries. Numerous studies in recent history have demonstrated that toothpicks are comparable to other dental implements at cleaning teeth effectively. In fact, toothpicks are much easier to use than dental floss and are thus much more likely to be used by children and the elderly to promote dental health. Further, many suggest that the use of toothpicks may facilitate the overcoming of oral fixations such as smoking, over-eating, and the like.
[0004] Toothpicks are typically formed as slivers of material, such as birch wood, having at least one end that is pointed for inserting in between the user's teeth. There are several methods currently available by which a toothpick can be manufactured to include other features, such as a flavor or helpful additive, such as fluoride. These methods typically involve coating or dusting the toothpick with a flavored compound or oil. However, these products generally lose their flavor and the effectiveness of any other additives in a relatively short time frame.
[0005] Accordingly, there remains a need to produce a toothpick with a greater ability to hold and to effectively deliver flavoring agents and other additives.
SUMMARY OF THE INVENTION
[0006] The present disclosure provides a flavored toothpick and a method for preparing such, the product fulfilling the need for a greater capacity and effectiveness in delivering flavoring and other desired additives. Other advantages in performance will be apparent to one having ordinary skill in the art.
[0007] Ina first aspect, the present disclosure provides a flavored toothpick, formed as a single piece of substrate from a wood material. The wooden substrate is pretreated to achieve an increase in porosity and a decrease in hardness. The pretreatment is performed with a wash of warm water, which may also include other chemicals to aid in the process, such as sodium hydroxide (NaOH). The hardness of the toothpick is typically decreased by more than 50% while the porosity is increased by more than 30%.
[0008] A second aspect of the present disclosure provides a method of preparing a flavored toothpick, where the toothpick is placed in a pretreatment wash as described above, and wherein the toothpick is placed in an additive solution at a raised temperature before curing the toothpick in an environment of low humidity.
[0009] Yet another aspect of the disclosure provides a method for preparing a flavored toothpick wherein flavoring and/or additives are infused into the substrate by placing the toothpick in a sealed chamber with the flavoring/additive solution under a vacuum. The toothpicks are then cured in a low humidity environment with heated forced air
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Further features and advantages of the present disclosure will be seen from the following detailed description, taken in conjunction with the accompanying drawings, wherein:
[0011] FIG. 1 is a schematic displaying a method for treating a toothpick substrate according to a first aspect of the present disclosure;
[0012] FIG. 2 is a flowchart displaying a method of preparing a flavored toothpick in accordance with another aspect of the present disclosure; and
[0013] FIG. 3 is a flowchart displaying a method of preparing a flavored toothpick using vacuum pressure in accordance with another aspect of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0014] In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown, by way of illustration, various embodiments of the present disclosure. It is understood that other embodiments may be utilized and changes may be made without departing from the scope of the present invention.
[0015] In a first aspect, the present disclosure provides an improved flavored toothpick. The toothpick is may be made from any number of substrates, but the present discussion will reference birch wood, which is the most common toothpick material used in North America. Compared to conventional toothpicks, the flavored function specific toothpicks of the present disclosure are softer and able to absorb a larger amount of flavoring and other desired additives. These improved characteristics are the direct result of a pretreatment of the birch wood prior to the flavoring step. This pretreatment of the wood removes certain constituents of the wood structure to bring about the softer feel and increased porosity. The increased porosity allows the toothpick to absorb an increased amount of flavoring or other additives. The increased softness is appealing to many toothpick users because it reduces the risk of injuring the user's gums.
[0016] Referring to FIG. 1 , the wood is pretreated by placing a batch of previously manufactured toothpicks 5 in a wash 10 of warm water. The water should be flowing, or at least agitated, in order to carry away “heavy cellulose” and other constituents 11 of the wood. For example, a batch of birch wood toothpicks is placed in a wash of water at a temperature of approximately 150° F. for approximately 1-2 hours. This process typically reduces the hardness of the final toothpick by over 50% compared to conventional toothpicks. While typical birch wood has a hardness of approximately 1260 lbs (as measured using the “Janka” test), the flavored toothpicks in accordance with the present disclosure exhibit hardness levels of approximately 300-500 lbs. Further, the same birch wood is estimated to have an increased porosity of over 30%, as observed by the additional uptake of injected material. Other organic materials may be similarly treated, exhibiting increased porosity of 10% or greater.
[0017] In order to decrease the wash time or temperature, or to target specific constituents of a particular toothpick substrate, the wash may also include other chemically active substances. For example, the pH of the wash may be slightly basic by adding a dilute solution of sodium hydroxide (NaOH) or sodium bicarbonate to result in a solution with pH above 7. This will target the cellulose structure of wood. In general, a basic solution is preferable because of its potential to remove portions of the cellulose, thereby increasing the porosity, without otherwise compromising the structural integrity of the wood. However, acidic solutions may also be used with wood to remove other constituents. Other chemical specific solutions may also be used with wood or other substrates as necessary or desired.
[0018] In another aspect, the present disclosure provides a process for making the flavored toothpicks described above. With reference to FIG. 2 , a toothpick in accordance with the disclosure is made by first preparing a super-saturated solution 1 of the desired additive (step 101 ). For example, a super-saturated caffeine solution is prepared by heating water to an elevated temperature sufficient to dissolve caffeine, for example between 140 and 180 degrees Fahrenheit. Once the desired additive has been dissolved, a masking agent 2 is added to the solution to mask any undesired flavor characteristics of the additive (step 102 ). Next, a sweetening agent 3 is added (step 103 ). Finally, 104 the flavoring 4 is added.
[0019] The desired additive may be caffeine, as mentioned above, or may be one or more of a number of biologically active compounds suitable for ingestion and having a variety of advantageous features. For example, in addition to caffeine, such biologically active compounds include a variety of botanicals, vitamins, homeopathic compounds, synthetic compounds, and the like, such as are now known—or come to be known—as suitable additives or nutritional supplements. Such compounds may also include addictive compounds such as nicotine or other chemicals, wherein the dental implement disclosed herein may be useful as an addiction recovery aid.
[0020] The solution may be water-based or alcohol-based, depending on the characteristics of the additive and flavoring considerations. The length of time that the solution remains at the elevated temperature is also dependent upon the characteristics of the additive and other constituents. Next, the toothpicks 5 are added to the heated solution and allowed to soak therein for a period of time sufficient for the solution to be fully absorbed into the toothpick (step 105 ).
[0021] In the example of the caffeinated toothpicks, the toothpicks are added to the heated solution and allowed to soak therein for a period of time sufficient for the solution to substantially permeate the matrix of the toothpick substrate. For example, the toothpicks may be added to the heated solution and left to soak therein for a period of time, such as, for example, a period of approximately three hours. During this time, the temperature of the solution is preferably maintained at approximately 140 degrees Fahrenheit or greater.
[0022] The infused toothpicks are then removed from the solution, drained and allowed to dry under conditions of low relative humidity 106 . The low humidity environment should be less than 18% relative humidity, but is preferably about 8-12% relative humidity. To expedite the drying process forced air, heated air, or a combination thereof may be used to increase the rate at which the picks give up the moisture contained therein. By way of example, forced air may be alternately forced into or drawn from the chamber. Using this method, the toothpicks of the present disclosure should be sufficiently cured within about one hour.
[0023] In the caffeine example, the solution will be comprised of approximately 50-70% water, 15-25% flavoring agent, 1-3% masking agent, 1-3% artificial sweetener (powder), and 7-10% caffeine (anhydrous). These amounts are approximate and will vary depending on the additive, the form it is provided in, and the base of the solution (water, alcohol, or otherwise). For instance, the artificial sweetener need not be provided in powder form, but could instead be provided as a liquid, and thereby comprise a greater volume percentage of the overall solution.
[0024] The flavoring agent may be a natural or artificial flavor. For example, the flavoring agent may be a water-soluble flavoring agent and may be comprised of one or more constituents, including, for example: almond flavor, almond toffee flavor, amaretto flavor, apple flavor, apple pie flavor, apricot crème flavor, bailey's Irish cream flavor, baklava flavor, banana flavor, banana cream flavor, banana nut bread flavor, banana's foster flavor, almond biscotti flavor, chocolate biscotti flavor, lemon & icing biscotti flavor, vanilla nut biscotti flavor, brown sugar flavor, black cherry flavor, triple berry flavor, bourbon flavor, Butterfinger™ flavor, butter cream flavor, butter pecan flavor, butter fum flavor, butterscotch flavor, caramel flavor, caramel apple flavor, caramel latte flavor, caramel macchiato flavor, chai flavor, cherry flavor, chocolate flavor, chocolate cream flavor, chocolate mint flavor, chocolate raspberry flavor, cinnamon flavor, coconut flavor, coconut crème flavor, coconut & rum flavor, cranberry flavor, crème brulee flavor, crème dementhe flavor, dulce de leche flavor, egg nog flavor, English toffee flavor, espresso flavor, frangelica flavor, french vanilla flavor, green tea flavor, hazelnut flavor, grand marnier flavor, highland grogg flavor, honey flavor, Irish cream flavor, Kona flavor, lemon drops flavor, licorice flavor, lime flavor, macadamia nut flavor, mandarin orange flavor, mango flavor, margarita flavor, marshmallow flavor, mocha flavor, passion fruit flavor, peach flavor, peaches and cream flavor, pear flavor, peppermint flavor, pineapple flavor, pina colada flavor, pistachio flavor, pomegranate flavor, praline flavor, pumpkin pie flavor, rain forest crunch flavor, raspberry flavor, rose flavor, rum flavor, Santa's Xmas flavor, Snickers™ flavor, snickerdoodle flavor, swiss chocolate almond flavor, spice flavor, strawberry flavor, oil-based sweetener flavor, sweet potato pie flavor, Tahitian vanilla flavor, tangerine flavor, tiramisu flavor, toasted almond flavor, toasted coconut flavor, vanilla flavor, vanilla spiced rum flavor, viennese flavor and white chocolate flavor.
[0025] The sweetening agent may be any suitable natural or artificial sweetener. In some examples, the sweetening agent is an artificial sweetener, selected from the group consisting of sucralose, aspartame, saccharin and acesulfame potassium.
[0026] The masking agent may be any suitable masking agent known in the art which is used in pharmaceutical supplements, foods and drinks to mask bitterness and/or enhance flavors. In one example, the masking agent is thaumatin or a derivative thereof. Thaumatin is a low calorie flavor modifier comprised of a natural protein extracted from the katemfe fruit, Thaumatococcus daniellii.
[0027] In one example of this aspect of the disclosure, the toothpicks are pretreated to increase the porosity and softness of the substrate. As discussed above, the substrate is pretreated, prior to the addition of the additive solution, by placing a batch of previously manufactured toothpicks 5 in a wash 10 of warm water. In order to decrease the wash time or temperature, or to target specific constituents of a particular toothpick substrate, the wash may also include other chemically active substances, including acids, bases, and the like.
[0028] Referring to FIG. 3 , another example of the present aspect of the disclosure uses vacuum pressure to infuse the flavoring and additives into the porous substrate of the toothpick (step 205 ). For purposes of the present disclosure, the word “infuse” refers specifically to the use of vacuum pressure to force the flavoring and/or the additive solution to fill the porous structure of the substrate. Using this process, it is possible to achieve a nearly homogeneous distribution of additives and/or flavoring throughout the substrate.
[0029] By way of example, a batch of toothpicks is placed in a bath of the additive solution in a sealed chamber 15 . A vacuum is applied to the chamber, for example, using a mechanical pump or compressor. Other machinery, such as liquid ring vacuum pumps may also be used, with varying amounts of pressure depending on the size of the batch, the strength of the material, and the solution.
[0030] While a small amount of pressure may be effective to significantly increase the uptake of the additive/flavoring, application of a vacuum of more than 10% below atmospheric pressure is useful to ensure that the substrate is fully saturated with the solution prior to the curing step 106 .
[0031] Alternatively, the vacuum step 205 may be used in connection with the pretreatment of the toothpick substrate. The resulting toothpicks absorb approximately 50-85% more of the additive and/or flavoring solutions, whether water or alcohol-based. Toothpicks prepared according to this process may also exhibit other features, including decreased hardness and increased size (girth). The toothpicks therefore deliver significantly more of the desired additive and the increased flavoring is long-lasting, having been infused into the substrate.
[0032] It should be emphasized that the above-described embodiments of the present device and process, particularly, and “preferred” embodiments, are merely possible examples of implementations and merely set forth a clearer understanding of the principles of the disclosure. Many different aspects of the disclosure described herein may be designed and/or fabricated without departing from the spirit and scope of the disclosure. For example, the above disclosure discusses birch wood as the substrate from which the toothpick is formed, but several other materials, both organic and man-made are well within the scope of the present disclosure, in accordance with the skill in the art. All these and other such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. Therefore the scope of the disclosure is not intended to be limited except as indicated in the appended claims. | A flavored toothpick and a method for preparing such, the product exhibiting improved capacity for delivering flavor and additives to the user, among other advantages. The toothpick may be prepared by pretreating the wooden substrate to increase porosity and decrease hardness. The toothpick is then immersed in a solution containing an additive, a masking agent, and a sweeting agent, where the toothpick absorbs the solution. Alternatively, the toothpick may be placed with the solution in a sealed chamber under vacuum pressure to infuse the toothpick with the additive solution and any desired flavoring. | 0 |
FIELD OF THE INVENTION
The invention relates to automobiles and, in particular, to a system and method for processing various images and detecting conditions in the driving environment based thereon and notifying the driver of certain conditions, when appropriate.
BACKGROUND OF THE INVENTION
Much of today's driving occurs in a demanding environment. The proliferation of automobiles and resulting traffic density has increased the amount of external stimulii that a driver must react to while driving. In addition, today's driver must often perceive, process and react to a driving condition in a lesser amount of time. For example, speeding and/or aggressive drivers give themselves little time to react to a changing condition (e.g., a pothole in the road, a sudden change of lane of a nearby car, etc.) and also give nearby drivers little time to react to them.
Despite advancements in digital signal processing technologies, including computer vision, pattern recognition, image processing and artificial intelligence (AI), little has been done to assist drivers with the highly demanding decision-making involved in normal driving. In one system implemented in the Cadillac DeVille, military “Night Vision” is adapted to detect objects in front of the automobile. Heat in the form of high emission of infrared radiation from humans, other animals and cars in front of the car is captured using cameras (focusing optics) and focused on an infrared detector. The detected infrared radiation data is transferred to processing electronics and used to form a monochromatic image of the object. The image of the object is projected by a head-up display near the front edge of the hood in the driver's peripheral vision. At night, objects that may be outside the range of the automobiles headlights may thus be detected in advance and projected via the heads-up display. The system is described in more detail in the document “DeVille Becomes First Car To Offer Safety Benefits Of Night Vision” at http://www.gm.com/company/gmability/safety/crash_avoidance/newfeatures/night_vision.html.
Among other deficiencies of the DeVille Night Vision system, the display only provides the thermal image of the object, and the driver is left to identify what the object is by the contour of the thermal image. The driver may not be able to identify the object. For example, the thermal contour of a person riding a bicycle (which has a relatively low thermal signature) may be too alien for a driver to readily discern. The mere presence of such an unidentifiable object may also be distracting. Finally, it is difficult for the driver to judge the relative position of the object in the actual environment, since the thermal image of the object is displayed near the front edge of the hood.
U.S. Pat. No. 5,414,439 to Groves et al. also relates to a Night Vision type system that outputs a video signal of a thermal image to a head up display (HUD). In one case, virtual images of pedestrians are projected below the actual image seen by the driver, thus forewarning the driver of pedestrians that may not be visible in the actual image. Alternatively, the virtual images are superimposed on the real scene. In U.S. Pat. No. 5,001,558 to Burley et al., light captured by a color camera is superimposed on thermal signals captured by an infrared imaging device. Thus, for example, a red signal light emitted by a traffic signal is captured by the color camera and superimposed on the thermal image created by the warm traffic signal and displayed.
A method of detecting pedestrians and traffic signs is described in “Real-Time Object Detection For “Smart” Vehicles” by D. M. Gavrila and V. Philomin, Proceedings of IEEE International Conference On Computer Vision, Kerkyra, Greece 1999 (available at www.gavrila.net), the contents of which are hereby incorporated by reference herein. A template hierarchy captures a variety of object shapes, and matching is achieved using a variant of Distance Transform based-matching, that uses a simultaneous coarse-to-fine approach over the shape hierarchy and over the transformation parameters. The Introduction section refers to informing the driver (or taking other measures) regarding certain potential hazards, such as a collision with a pedestrian, speeding, or turning the wrong way down a one-way street. It is noted, however, that the focus of the document is on detection of the above-mentioned objects and does not describe how or the particular circumstances under which the driver is alerted of a potentially hazardous situation.
A method of detecting pedestrians on-board a moving vehicle is also described in “Pedestrian Detection From A Moving Vehicle” by D. M. Gavrila, Proceedings Of The European Conference On Computer Vision, Dublin, Ireland, 2000, the contents of which are hereby incorporated by reference herein. The method builds on the template hierarchy and matching using the coarse-to-fine approach described above, and then utilizes Radial Basis Functions (RBFs) to attempt to verify whether the shapes and objects are pedestrians. The focus of the document is also on detection of pedestrians and does not describe alerting of the driver.
“Autonomous Driving Approaches Downtown” by U. Franke et al., IEEE Intelligent Systems, vol. 13, no. 6, 1998 (available at www.gavrila.net) describes an image recognition that focuses on application to autonomous vehicle guidance. The Introduction section refers to numerous prior art vision systems for lateral and longitudinal vehicle guidance, lane departure warning and collision avoidance. The document describes image recognition of pedestrians, obstacles (such as other automobiles), road boundaries and markings, traffic signals and traffic signs. While the focus of the document is on vehicle guidance, among other things, the document also refers to rear-end collision avoidance or red traffic light recognition and warning, tracking road contours and providing a lane departure warning, and warning the driver when driving faster than the speed limit. In particular, FIG. 4.9 shows a display of a detected red light, where an enlarged and prominent image of the red light is displayed adjacent the actual image of the red light in a monitor-style display. (See, also, “Smart Vehicles” at www.gavrila.net/Computer_Vision/Smart_Vehicles/smart_vehicles.html, which indicates that a monitor-style display is used.)
SUMMARY OF THE INVENTION
The prior art fails to provide a comprehensive system that detects potentially hazardous traffic situations via image recognition, and then present an image of the hazard to the driver in a manner that is designed to alert the driver without unnecessarily distracting him or her and effectively provide the location of the potential hazard.
It is thus an objective of the invention to provide a system and method for alerting a driver of an automobile to a traffic condition. The system comprises at least one camera having a field of view and facing in the forward direction of the automobile. The camera captures images of the field of view in front of the automobile. A control unit receives images of the field of view from the camera and identifies objects therein of at least one predetermined type. The control unit analyzes the object images of the at least one predetermined type to determine whether one or more of the identified objects of the at least one predetermined type present a condition that requires the driver's response. A display receives control signals from the control unit regarding those objects of the at least one predetermined type that present a condition that requires the driver's response. The display displays an image of those objects that require a response to the driver that is positioned and scaled so that it overlays (is superimposed with respect to) the actual object as seen by the driver, the displayed image of the object enhancing a feature of the actual object to alert the driver.
The method comprises the steps of first capturing images of the field of view in front of the automobile. Objects in the image of at least one predetermined type are identified and analyzed to determine whether one or more of the identified objects present a condition that requires the driver's response. If at least one of the objects identified in the image requires the driver's response an image of the object is displayed to the driver. The displayed image is positioned and scaled so that it overlays the actual object as seen by the driver. The displayed image of the object enhances a feature of the actual object to alert the driver.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of an automobile that incorporates an embodiment of the invention;
FIG. 1 a is a top view of the automobile of FIG. 1;
FIG. 2 is a representative drawing of components of the embodiment of FIGS. 1 and 1 a and other salient features used to describe the embodiment;
FIG. 3 is an image generated by the camera of the embodiment of FIGS. 1-2;
FIG. 3 a is as described for FIG. 2 and further includes an image projected by the system onto the windshield;
FIG. 4 is a representative drawing of components of an alternative embodiment and other salient features used to describe the embodiment;
FIGS. 5 a and 5 b are images generated by the cameras of the embodiment of FIG. 4; and
FIG. 6 is a representative drawing of geometrical relationships used to describe the embodiment of FIGS. 4-5 b.
DETAILED DESCRIPTION
Referring to FIG. 1, an automobile 10 is shown that incorporates an embodiment of the invention. As shown, camera 14 is located at the top of the windshield 12 with its optic axis pointing in the forward direction of the automobile 10 . The optic axis (OA) of camera 14 is substantially level to the ground and at substantially the same position along the dashboard as the driver, as shown in FIG. 1 a . Camera 14 captures images in front of the automobile 10 . The field of view of camera 14 is preferably on the order of 180°, thus the camera captures substantially the entire image in front of the auto. The field of view, however, may be less than 180 °.
Referring to FIG. 2, additional components of the system that support the embodiment of the invention, as well as the relative positions of the components and the driver's head P are shown. FIG. 2 shows the position of the driver's head P in its relative position on the left hand side, behind the windshield 12 . Camera 14 is on the portion of the windshield 12 directly in front of, and slightly above, the driver's head P, as represented by the dashed lines between camera 14 and driver's head P in FIG. 2 .
Thus, as a first order approximation, the center and perspective of the field of view of the camera 14 corresponds to that of the field of view of the driver P. Images captured by camera 14 are transferred to control unit 20 . The field of view of the driver P and camera 14 of FIG. 2 includes, for example, stop sign 28 .
Referring to FIG. 3, stop sign 28 and the surrounding environment is shown in the images received by control unit 20 at a point in time from camera 14 . Control unit 20 is programmed with image recognition software that analyzes the images received and detects traffic signs, human bodies, other automobiles, the boundaries of the roadway and objects or deformations in the roadway, among other things. The image recognition software may incorporate, for example, the shape-based object detection described in the “Real-Time Object Detection for “Smart” Vehicles” noted above. Among other objects, the control unit 20 is programmed to identify the shapes of various traffic signs, such as the stop sign 28 in FIG. 3 .
Once the image recognition software identifies the stop sign 28 of FIG. 3 in an image received from fine camera 14 , the control unit 20 may be programmed, for example, to immediately alert the driver of the upcoming stop sign, or to alert the driver under certain circumstances. For example, the size of the template generated for the stop sign in the shape-based object detection technique described in “Real-Time Object Detection for “Smart” Vehicles” may be correlated to distance from the automobile in control unit 20 . If the control unit 20 determines that the speed of the automobile is excessive in relation to the distance to the stop sign 28 , an alert may be generated.
In the embodiment, the alert of the impending stop sign 28 is provided by providing an enhanced image of the stop sign 28 to the driver P on a head-up display (HUD) 24 connected to control unit 20 . Control unit 20 is programmed to translate the coordinates of objects in the image to a position on the windshield. For example, the outline of the windshield 12 relative to the image shown in FIG. 3 is given by the dashed line. As a first-order approximation, control unit 20 may linearly map the stop sign 28 from the image to its corresponding position on the windshield via the HUD 24 . As previously noted, the center and perspective of the field of view of camera 14 is approximately the same as that of the driver P. Thus, the size and position of the image of the stop sign 28 projected by the HUD 28 on the windshield will substantially overlay the actual stop sign 28 as seen by the driver P through the windshield. This is shown in FIG. 3 a , which depicts the image of the stop sign 28 i projected by the HUD 24 optics onto windshield 12 that overlays the actual stop sign 28 in the driver's field of view. In order to gain the driver's attention, the projected image may be made to flash, increase in intensity, or other visual cue to gain the driver's attention. If the control unit 20 determines that the driver P is not responding (for example, the speed does not decrease), the alert may intensify, for example, through brighter flashing, the addition of an audio alert, or other.
As noted, the control unit 20 of the above-described embodiment of the invention may be programmed to detect stop signs and other traffic control signs and to detect situations that require the driver be alerted. In other examples, if the automobile 10 is detected as heading toward a “Do Not Enter” or “Wrong Way” sign, the sign is highlighted via the overlaying image projected by the HUD 24 or other alert is given. (As noted, the control unit 20 can project the direction in which the car is traveling from the image, since the OA of the camera 14 is directed forward with respect to the auto. The control unit 20 may also receive the automobile's speed from the automobile's processor, the direction in which the automobile is turning from sensors on steering components, etc.) Similarly, the control unit 20 may be programmed to detect the contour of a traffic signal and to also analyze the current color state of the signal (red, amber or green). If the signal is red or amber, for example, and the automobile 10 is not slowing, the HUD 24 is used to project an overlaying image that highlights the actual signal and alert the driver.
In addition, the image gradient of the borders of the road may be detected as a “shape” using the template method in the shape-based object detection technique described in “Real-Time Object Detection for “Smart” Vehicles”. If the direction of the automobile 10 is detected to intersect the border of the road, signifying that the driver is swerving off the road, the HUD 24 may be engaged to highlight the contour of the road to the driver as an alert. As noted, the HUD alert may intensify and audio alerts may be generated if the auto is not slowed, or the course is not corrected. Certain additional circumstances may have to be present in order to generate the alert. For example, if a car is turned at an intersection (for example, such as that shown in FIG. 3 ), it will be temporarily pointed at the border of the road onto which the auto is being turned. Thus, the alert is not generated if the control unit 20 detects that the contours of the roadways in the image comprise an intersection (such as that shown in FIG. 3) and also detects that the auto is making a consistent turn when the current image depicts that the auto is within the intersection. Alternatively, over short intervals the control unit 20 may determine the distance to the border of the roadway in the direction the auto is heading based upon the size and shape of the template that matches the roadway in the image. If the auto is traveling at or above a threshold speed in relation to the distance to the border of the roadway, the alert is generated.
In general, control unit 20 analyzes a succession of received images and identifies the traffic signs, roadway contour, etc. in each such image. All of the images may be analyzed or a sample may be analyzed over time. Each image may be analyzed independently of prior images. In that case, a stop sign (for example) is independently identified in a current image received even if it had previously been detected in a prior image received. The various thresholds and conditions for generating an alert are based on the conditions that are detected by the control unit 20 for the images as identified in each image.
Alternatively, if an object is identified in an image as being a control signal, traffic sign, etc., control unit 20 may be further programmed to track its movement in subsequently received images, instead of independently identifying it anew in each subsequent image. Tracking the motion of an identified object in successive images based on position, motion and shape may rely, for example, on the clustering technique described in “Tracking Faces” by McKenna and Gong, Proceedings of the Second International Conference on Automatic Face and Gesture Recognition, Killington, Vt., Oct. 14-16, 1996, pp. 271-276, the contents of which are hereby incorporated by reference. (Section 2 of the aforementioned paper describes tracking of multiple motions.) By tracking the motion of an object between images, control unit 20 may also determine its speed and trajectory relative to the automobile. The detected speed and trajectory may supply the conditions under which the control unit 20 projects an alert via the HUD 24 to the driver in the form of an enhanced overlay of a traffic sign, traffic signal, etc.
As noted above, the control unit 20 of the above-described embodiment of the invention may also be programmed to detect objects that are themselves moving, such as pedestrians and other automobiles and to alert the driver using the HUD 24 to possible collision trajectories or other dangerous situations. Where pedestrians and other objects in motion are to be detected (along with traffic signals, traffic signs, etc.), control unit 20 is programmed with the identification technique as described in “Pedestrian Detection From A Moving Vehicle”. As noted, this provides a two step approach for pedestrian detection that employs an RBF classification as the second step. The template matching of the first step and the training of the RBF classifier in the second step may also include automobiles, thus control unit 20 is programmed to identify pedestrians and automobiles in the received images. (The programming may also include templates and training for the stationary traffic signs, signals, roadway boundaries, etc. focused on above, thus providing the entirety of the image recognition processing of the control unit 20 .)
Once an object is identified as a pedestrian, other automobile, etc. by control unit 20 , its movement may be tracked in subsequent images using the clustering technique as described in “Tracking Faces”, noted above. Control unit 20 uses the tracking data to determine the current speed and direction of movement of a pedestrian or other automobile relative to the current position of automobile 10 . Control unit 20 also uses the speed and direction of movement of automobile 10 to project a trajectory of automobile 10 . If the projected trajectory of the pedestrian or other automobile and the projected trajectory of the automobile 10 cross within a certain interval of time in the future, then an alert of a potential collision is generated by the control unit 20 . Other conditions may be required before an alert is generated, such as a minimum threshold proximity in time before a collision is projected to occur. (This would eliminate, for example, alerting a driver to a collision course with a pedestrian that is two blocks away, where the trajectories of the pedestrian and automobile 10 will likely change long before a collision occurs.)
As described above, when an alert is generated, control unit 20 linearly maps the pedestrian, automobile, or other object (including a stationary object) that is on a collision course with the automobile 10 from the image to its corresponding position on the windshield via the HUD 24 . The image projected by the HUD 28 on the windshield is positioned and scaled so that it substantially overlays the actual pedestrian, automobile, etc. as seen by the driver P through windshield 12 . In order to gain the driver's attention, the projected image may be made to flash, increase in intensity, or other visual cue to gain the driver's attention. If the control unit 20 determines that the driver P is not responding (for example, the speed does not decrease), the alert may intensify, for example, through brighter flashing, the addition of an audio alert, or other.
The alert initiated by control unit 20 can also warn the driver P of an unpredictable or dangerous situation, not necessarily the projection of a collision. For example, if another automobile identified by the control unit 20 is tracked and detected to be speeding, weaving, or conforming to other conditions indicating a potential hazard, the alert of the other automobile is generated. Also, cameras may be directed out of the back window and side windows of the automobile 10 and provide alerts based on potential side or rear collisions, potentially hazardous conditions from the side or rear, etc. The alert may be in the form of a HUD associated with the side or rear window generating an enhanced image that overlays the view of the actual identified object as seen through the side or rear window, and providing an audio alert (such as a recorded message) directing the driver's attention to the pertinent side or rear of the automobile. Thus, for example, if a reckless driver in another automobile is identified by control unit 10 as bearing down on the automobile 10 from the rear, the HUD overlay image of the other automobile is enhanced in the rear window and a recording (such as “auto fast approaching from rear”) will alert the driver P to look in the rear-view mirror, where his eye will immediately be directed to the enhanced image that corresponds to the actual image. The enhancement may include, for example, flashing the image, intensifying the image or its borders, or other.
For the embodiment described above and shown in FIG. 2, control unit 20 linearly maps the image of the identified object to which an alert is being generated from the received camera image to its corresponding position on the windshield via the HUD 24 . In the embodiment of FIG. 2, the center and perspective of the field of view of camera 14 is approximately the same as that of the driver P. The image of the object as mapped from the image received by the camera to the windshield 12 and then projected by the HUD 28 on the windshield substantially overlays the actual object as seen by the driver P through the windshield 12 (see FIG. 3 a ). This, however, is only a first order approximation of the position and size of the identified object on the windshield that corresponds to the actual object as seen by the driver through the windshield. It does not account for the curvature of the windshield, non-linearities of the optics of camera 20 , etc.
FIG. 4 depicts an alternative embodiment where the identified object is projected on the HUD in a manner that more precisely aligns and scales the projected image to overlay the actual image that the driver views through the windshield. Two cameras 14 a , 14 b located at the right and left hand sides of windshield 12 provide images to control unit 20 . The position of camera 14 a coincides with the origin of a reference coordinate system, where the z-axis is in the direction of the optic axis of camera 14 a (and the direction the automobile 10 is facing), the y-axis is upward and the x-axis is across the car or dashboard. The control unit 20 is programmed with the nominal coordinates of the driver's head (or eyes) in the reference coordinate system, shown as (A,B,C) in FIG. 4 . In addition, the coordinates of points comprising the windshield 12 in the reference coordinate system are also programmed in control unit 20 . (A matrix of points comprising the windshield may be used, a functional relationship defining the windshield may be used, or some combination may be used.)
Control unit 20 receives images from both cameras 14 a , 14 b and identify objects, pedestrians, automobiles, etc., in the manner previously described. In FIG. 4, a stop sign 28 is again shown as an exemplary object that is identified in the images. FIGS. 5 a and 5 b depict the identified object as seen in images from cameras 14 a and 14 b , respectively. The center of stop sign 28 is at unknown position (X s ,Y s ,Z s ) in the reference coordinate system. Control unit 20 identifies the center of the stop sign 28 in the camera images shown in FIGS. 5 a and 5 b as having image coordinates (x′,y′) and (x″,y″), respectively, with respect to image origins O′ and 0 ″ at the bottom center of the images. Unknown coordinates (X s ,Y s ,Z s ) of the position the stop sign in the reference coordinate system of FIG. 4 may then be uniquely determined using standard techniques of computer vision known as the “stereo problem”. Basic stereo techniques of three dimensional computer vision are described for example, in “Introductory Techniques for 3-D Computer Vision” by Trucco and Verri, (Prentice Hall, 1998) and, in particular, Chapter 7 of that text entitled “Stereopsis”, the contents of which are hereby incorporated by reference. Using such well-known techniques, the relationship between the center of the stop sign in FIG. 4 (having unknown coordinates (X s ,Y s ,Z s )) and the image position (x′, y′) of the center of the stop sign in FIG. 5 a is given by the equations:
x′=X s /Z s (Eq. 1)
y′=Y s /Z s (Eq. 2)
Similarly, the relationship between the position of the stop sign in FIG. 4 and the image position of the stop sign in FIG. 5 b (having known image coordinates (x″,y″)) is given by the equations:
x ″=( X s −D )/ Z s (Eq. 3)
y″=Y s /Z s (Eq. 4)
where D is the distance between cameras 14 a , 14 b . One skilled in the art will recognize that the terms given in Eqs. 1-4 are up to linear transformations defined by camera geometry.
Equations 1-4 have three unknown variables (coordinates X s ,Y s ,Z s ), thus the simultaneous solution by the control unit 20 gives the values of X s ,Y s , and Z s and thus gives the position of the center of the stop sign 28 in the reference coordinate system of FIG. 4 . Control unit 20 plots a line between the stop sign and the coordinates of the driver P located at (A,B,C), and determines where the line intersects a coordinate of the windshield 12 (which, as described above, are programmed in control unit 20 ). This point is shown as point I in FIG. 4 . Thus, the control unit 20 creates the image of the stop sign 28 centered at the point I using the HUD 24 .
As noted, the size and perspective of the image of the stop sign 28 on the windshield is also scaled so that it corresponds to (overlays) the actual stop sign 28 as seen by the driver through the windshield. Control unit 20 may scale the image of the stop sign 28 projected by the HUD 24 based on the size of the template used in matching the image. Alternatively, the image may be scaled using the distance between the driver P and the stop sign 28 , the distance between the point I on the windshield and the stop sign 28 , and the size of the actual stop sign. (The two distances may be readily calculated by control unit 20 based on the known coordinates of the stop sign 28 , driver P and point I in the reference coordinate system.) Referring to FIG. 6, a good first order approximation of the scaling of the image of the stop sign 28 about point I on the windshield 12 is given as:
S=L*N/M
where S is the scaling factor used to scale the frontal dimensions of the actual stop sign 28 for generating the image depicted on the windshield 12 , N is the distance from the driver P to the point I, M is the distance from the driver P to the stop sign 28 and L is the nominal or average width of the face frontal of the stop sign 28 . The scaling factor S is used to scale the various frontal dimensions of the stop sign 28 for the HUD projection of the image of the stop sign on the windshield 12 about the point I.
Alternatively, instead of determining only the position of the central point I on the windshield 12 of the image of the stop sign, the position on the windshield for a number of specific points on the border of the actual stop sign 28 may also be determined in the same manner as for point I. The control unit 20 creates an image of the stop sign on the windshield that incorporates the specific points in the pertinent location on the border of the image. Thus, an overlaying image of the stop sign is created having the correct scale and position on the windshield.
Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, but rather it is intended that the scope of the invention is as defined by the scope of the appended claims.
The following documents are also hereby incorporated by reference herein:
1) U.S. patent application Ser. No. 09/953,642, entitled “Intelligent Quad Display Through Cooperative Distributed Vision”, for Srinivas Gutta et al., filed Sep. 17, 2001.
2) U.S. patent application Ser. No. 09/794,443, entitled “Classification Of Objects Through Model Ensembles” for Srinivas Gutta and Vasanth Philomin, filed Feb. 27, 2001,
3) U.S. patent application Ser. No. 09/703,423, entitled “Person Tagging In An Image Processing System Utilizing A Statistical Model Based On Both Appearance And Geometric Features” for Antonio Colmenarez and Srinivas Gutta, filed Nov. 1, 2000.
4) Announcement document “Siemens VDO's Color Head-Up Display Nears First Application”, Sep. 12, 2001, published at www.itsa.org/itsnews.nsf/$A11/2E4A7421A07B0D6085256AC50067468A?OpenDocum ent.
5) “Autonomous Driving Approaches Downtown” by U. Franke et al., IEEE Intelligent Systems, vol. 13, no. 6, 1998 (available at www.gavrila.net) | A system and method for alerting a driver of an automobile to a traffic condition. The system comprises at least one camera having a field of view and facing in the forward direction of the automobile. The camera captures images of the field of view in front of the automobile. A control unit receives images of the field of view from the camera and identifies objects therein of a predetermined type. The control unit analyzes the object images of at least one predetermined type to determine whether one or more of the identified objects present a condition that requires the driver's response. A display receives control signals from the control unit regarding the one or more of the objects that present a condition that requires the driver's response. The display displays an image of the object to the driver that is positioned and scaled so that it overlays the actual object as seen by the driver, the displayed image of the object enhancing a feature of the actual object to alert the driver. | 1 |
FIELD OF THE INVENTION
[0001] The present invention relates to apparatus and methods for securing a tubular within another tubular or borehole, isolating an annulus or centralising sections of pipe. In particular the invention has application for centralising and/or securing a casing tubular or liner tubular within another casing section, liner section or open borehole in an oil, gas or water well and for isolating a portion of a borehole located below the apparatus from a portion of the borehole located above the apparatus.
BACKGROUND OF THE INVENTION
[0002] Oil, gas or water wells are conventionally drilled with a drill string, which comprises drill pipe, drill collars and drill bit(s). The drilled open hole is hereinafter referred to as a “borehole”. A borehole is typically provided with casing sections, liners and/or production tubing. The casing is usually cemented in place to prevent the borehole from collapse and is usually in the form of at least one large diameter pipe.
SUMMARY OF THE INVENTION
[0003] According to a first aspect of the present invention there is provided apparatus comprising:
a tubular section arranged to be run into and secured within a larger diameter generally cylindrical structure; at least one sleeve member wherein the sleeve member is positioned on the exterior of the tubular section and sealed thereto; and pressure control means operable to alter the pressure within the sleeve member such that an increase in pressure causes the sleeve to move outwardly and bear against an inner surface of the larger diameter structure.
[0007] The large diameter structure may be an open hole borehole, a borehole lined with a casing or liner string which may be cemented in place downhole, or may be a pipeline within which another smaller diameter tubular section requires to be secured or centralised.
[0008] The tubular section is preferably located coaxially within the sleeve. Therefore the present invention allows a casing section or liner to be centralised within a borehole or another downhole underground or above ground pipe by provision of an expandable sleeve member positioned around the tubular section.
[0009] The tubular section can be used within a wellbore, run into an open or cased oil, gas or water well. The tubular section may be a part of a liner or casing string. In this context, the term “liner” refers to sections of casing string that do not extend to the top of the wellbore, but are anchored or suspended from the base region of a previous casing string. Sections of liner are typically used to extend further into a wellbore, reduce cost and allow flexibility in the design of the wellbore.
[0010] As previously stated casing sections are often cemented in place following their insertion into the borehole. Extension of the wellbore can be achieved by attaching a liner to the interior of a base portion of a casing section. Ideally the liner should be secured in position and this is conventionally achieved by cementing operations. However, cementing sections of liner in place is time consuming and expensive. The present invention can be used as a means to centralise and secure such a liner section, thus removing the need for cementing.
[0011] Downhole embodiments of the apparatus can be used to isolate one section of the downhole annulus from another section of the downhole annulus and thus can also be used to isolate one or more sections of downhole annulus from the production conduit. The apparatus preferably comprises a means of securing the sleeve member against the exterior of the tubular member which may be a casing section or liner wall and preferably, the sleeve member provides a means of creating a reliable hydraulic seal to isolate the annulus, typically by means of an expandable metal element.
[0012] The sleeve member can be coupled to the casing section or liner by means of welding, clamping or other suitable means.
[0013] Preferably the apparatus is also provided with seal means. The function of the seal means is to provide a pressure tight seal between the exterior of the tubular section and the sleeve member, which may be the interior or one or both ends of the sleeve member.
[0014] The seal means can be mounted on the tubular section to seal the sleeve member against the exterior of the tubular section. A chamber is created, which chamber is defined by the outer surface of the tubular section, the inner surface of the sleeve member and an inner face of the seal means. The seal means may be annular seals which may be formed of an elastomer or any other suitable material.
[0015] The sleeve may be manufactured from metal which undergoes elastic and plastic deformation. The sleeve is preferably formed from a softer and/or more ductile material than that used for the casing section or liner. Suitable metals for manufacture of the sleeve member include certain types of steel. Further, the sleeve member may be provided with a coating such as an elastomeric coating. In addition the sleeve member may be provided with a non-uniform outer surface such as ribbed, grooved or other keyed surface in order to increase the effectiveness of the seal created by the sleeve member when secured within another casing section or borehole.
[0016] According to another aspect of the present invention, the pressure control means comprise a hydraulic tool equipped with at least one aperture. Additionally, the tubular section preferably comprises at least one port to permit the flow of fluid into and out of the chamber created by the sleeve member. In operation the hydraulic tool is capable of delivering fluid through the aperture of the hydraulic tool under pressure and through the at least one port in the tubular member into the chamber. The hydraulic tool may contain hydraulic or electrical systems to control the flow and/or pressure of said fluid.
[0017] The pressure control means may also be operable to monitor and control the pressure within the casing section. The pressure in the sleeve member is preferably increased between seal means and may be achieved by introduction of pressurised fluid.
[0018] Pressure within the sleeve member is preferably increased so that the sleeve member expands and contacts the outer casing or borehole wall, until sufficient contact pressure is achieved resulting in a pressure seal between the exterior of the sleeve member and the inner surface of the casing or borehole wall against which the sleeve member can bear. Ideally, this pressure seal should be sufficient to prevent or reduce flow of fluids from one side of the sleeve member to the other and/or provide a considerable centralisation force.
[0019] The initial outside diameter of the sleeve member can increase on expansion of the sleeve member to seal against the interior of the wellbore or other casing section.
[0020] The sleeve can be expanded by various means. According to one aspect of the invention, the tubular section is provided with at least one port formed through its sidewall and positioned between the seals of the sleeve member to allow fluid under pressure to travel therethrough from a throughbore of the tubular section into the chamber.
[0021] The port(s) may be provided with check valves or isolation valves which, on hydraulic expansion of the sleeve into its desired position, act to prevent flow of fluid from the chamber to the throughbore of the tubular section to preferably maintain the sleeve in its expanded configuration once the hydraulic tool is withdrawn. In this context, check valve or isolation valve is intended to refer to any valve which permits flow in only one direction. The check valve design can be tailored to specific fluid types and operating conditions.
[0022] Alternatively, the port(s) may be provided with a ruptureable barrier device, such as a burst disk device or the like, which prevents fluid flow through the port(s) until an operator intentionally ruptures the barrier device by, for example, applying hydraulic fluid pressure to the tubing side of the barrier device until the pressure is greater than the rated strength of the barrier device. The use of such optional barrier device can be advantageous if an operator wishes to keep well fluids out of the sleeve chamber until the sleeve is ready for expansion.
[0023] Another method of effecting expansion of the sleeve member involves insertion of a chemical fluid which can set to hold the sleeve member in place. An example of such fluid is cement.
[0024] Towards the end of each sleeve member, sliding seals between the interior of the sleeve member and exterior of the tubular casing may be provided. A sliding seal allows movement in a longitudinal direction to shorten the distance between the ends of the sleeve member such that outward movement of the sleeve does not cause excessive thinning of the sleeve member.
[0025] Expansion of the sleeve can be facilitated by provision of a sliding seal and/or through elastic and/or plastic deformation when the sleeve member yields. The sleeve member should preferably expand such that contact is effected between the exterior of the sleeve member and another pipe or borehole wall. In this way the at least one outer sleeve can be used to support or centralise the tubular member within an outer tubular member or borehole. The apparatus can also be used to isolate one part of annular space from another section of annular space. The outer sleeve members can be utilised to centralise one casing section within another or within an open hole well section.
[0026] There can be a plurality of sleeve members on a casing section to isolate separate zones and separate formations from one another. The plurality of sleeve members may be expanded individually, in groups or simultaneously. In a situation when it is desired that all sleeve members are expanded simultaneously, this can be achieved by increasing the pressure within the entire casing section. Expansion of individual sleeve members or groups of sleeve members can be achieved by plugging or sealing internally above and below the ports which communicate with the respective sleeve members to be expanded and the pressure between these seals can be increased to the desired level.
[0027] In preferred embodiments, the apparatus further comprises a sealant material provided on the outer surface of said sleeve and more preferably, the sealant material is provided with a protective covering layer or yet further outer sleeve member. Said further outer sleeve member may be unitary in fashion in order to seal the sealant material within a chamber defined between the inner surface of said further outer sleeve member and the outer surface of the aforementioned sleeve member. Alternatively, the yet further outer sleeve member may be provided with perforations or apertures therein to permit the sealant material to be extruded from said chamber when the said sleeve member is expanded radially outwardly in order to further enhance the seal provided by the apparatus.
[0028] In certain circumstances it is necessary to isolate portions of annular space from adjacent portions within a wellbore. The present invention also creates a reliable seal to isolate the annulus.
[0029] The apparatus has a dual function since it can be utilised with concentric tubulars such as pipelines to support or centralise the inner member inside an outer member and to isolate one part of annular space from another.
[0030] According to another aspect of the present invention, a casing section is provided with perforations. In this situation sleeve members may be located either side of a perforation in the casing section allowing fluid from the well to enter the casing through the perforation, with the expandable sleeve members acting as an impediment to prevent fluid from entering different annular zones.
[0031] The casing section or liner should be designed to withstand a variety of forces, such as collapse, burst, and tensile failure, as well as chemically aggressive brines. Casing sections may be fabricated with male threads at each end, and short-length couplings with female threads may be used to join the individual joints of casing together.
[0032] Alternatively the joints of casing may be fabricated with male threads on one end and female threads on the other. The casing section or liner is usually manufactured from plain carbon steel that is heat-treated to varying strengths, but other suitable materials include stainless steel, aluminium, titanium and fibreglass.
[0033] In accordance with the present invention there is also provided a method comprising the steps of:
sealing at least one expandable sleeve member on the exterior of a tubular section; inserting the casing section into a generally cylindrical structure; and providing pressure control means operable to increase the pressure within the sleeve member, such that the pressure increase causes the sleeve member to move outwardly allowing the exterior surface of the sleeve member to bear against the inner surface of the generally cylindrical structure.
[0037] In certain preferred embodiments the method is useful for centralising one pipe within another or within an open hole well section. More preferably, the apparatus and method are useful in isolating a section of borehole located below the expandable sleeve member from a section of borehole located above the expandable sleeve member.
[0038] The above-described method comprises inserting the casing section into another section or borehole to the required depth. This may be by way of incorporating the casing section into a casing or liner string and running the casing/liner string into the other section or borehole.
[0039] Pressure, volume, depth and diameter of the sleeve member at a given time during expansion thereof can be recorded and monitored by either downhole instrumentation or surface instrumentation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings in which:—
[0041] FIG. 1 is a cross-sectional view of a first embodiment of a casing section with surrounding sleeve welded thereto;
[0042] FIG. 2 is a cross-sectional view of a second embodiment of a casing section with an outer sleeve mechanically clamped thereto at one end and a sliding seal provided at the other end;
[0043] FIG. 3 is a cross-sectional view of a third embodiment of a casing section with an outer sleeve mechanically clamped at both ends;
[0044] FIG. 4 is a cross-sectional view of the casing section and attached outer sleeve of FIG. 3 and an hydraulic expansion tool therein;
[0045] FIG. 5 is a cross-sectional view of the casing section of FIG. 2 and expanded outer sleeve in contact with a borehole wall;
[0046] FIG. 6 shows a sequence for expanding two sleeve members;
[0047] FIG. 6 a is a cross-sectional view of a perforated liner provided with two sleeve members;
[0048] FIG. 6 b shows the perforated liner in a borehole of FIG. 6 a with a hydraulic expansion tool inserted therein; and
[0049] FIG. 6 c is a cross-sectional view of the perforated liner of FIGS. 6 a and 6 b with expanded sleeves;
[0050] FIG. 7 is a half-cross-sectional view of a portion of a perforated liner or casing provided with a fourth embodiment of an outer sleeve member and being located in a borehole just prior to actuation by a hydraulic expansion tool (not shown);
[0051] FIG. 8 is a half-cross-sectional view of the sleeve member of FIG. 7 in contact with the borehole wall after actuation by the hydraulic expansion tool;
[0052] FIG. 9 a is a full-cross-sectional view of the sleeve member of FIG. 8 ;
[0053] FIG. 9 b is a detailed view of a portion of the sleeve member of FIG. 9 a;
[0054] FIG. 10 is a half-cross-sectional view of a portion of a liner or casing provided with a fifth embodiment of a perforated outer sleeve member and being located in a borehole just prior to actuation by a hydraulic expansion tool (not shown);
[0055] FIG. 11 is a half-cross-sectional view of the sleeve member of FIG. 10 in contact with the borehole wall after actuation by the hydraulic expansion tool;
[0056] FIG. 12 a is a full-cross-sectional view of the sleeve member of FIG. 10 ; and
[0057] FIG. 12 b is a detailed view of a portion of the sleeve member of FIG. 12 a.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0058] FIG. 1 shows an apparatus 10 in accordance with the present invention. A casing is generally designated at 1 and provided with two sets of circumferential equispaced holes through its sidewall; upper ports 2 u and lower ports 2 L. However, it should be noted that casing 1 could be modified by only providing one set of ports 2 which could be located at the middle of the length of the casing 1 , and furthermore could be modified by only providing one such port 2 . Casing 1 is located coaxially within sleeve 3 . The casing 1 may be either especially manufactured or alternatively is preferably conventional steel casing with ports 2 formed therein. The sleeve 3 is typically 316 L grade steel but could be any other suitable grade of steel or any other metal material or any other suitable material.
[0059] The apparatus 10 comprises a sleeve 3 which is a steel cylinder with tapered upper and lower ends 3 u and 3 L and an outwardly waisted central section 3 c having a relatively thin sidewall thickness. Sleeve 3 circumferentially surrounds casing 1 and is attached thereto at its upper end 3 u and lower end 3 L, via pressure-tight welded connections 4 .
[0060] Since the central section of sleeve 3 is waisted outwardly and is stood off from the casing 1 , this portion of the sleeve 3 is not in direct contact with the exterior of the casing 1 which it surrounds. The inner surface of the outwardly waisted section 3 c of sleeve and the exterior of the casing 1 define a chamber 6 .
[0061] Upper O-ring seals 5 u are also provided towards the upper end of sleeve 3 u but interior of the upper welded connection 4 . Similarly lower seals 5 L are positioned towards the lower end of sleeve 3 L but are also positioned interior of the lower welded connections. Seals 5 u and 5 L are in direct contact with the exterior of the casing and the ends of the sleeve, 3 u and 3 L thereby providing a pressure tight connection between the interior of sleeve 3 and the exterior of casing 1 and thus act as a secondary seal or backup to the seal provided by the welded connections 4 .
[0062] Ports 2 u and 21 permit fluid communication between the interior or throughbore of casing 1 and chamber 6 .
[0063] A second embodiment of an apparatus 20 in accordance with the present invention is shown in FIG. 2 and comprises a sleeve 23 which is substantially cylindrical in shape with upper and lower ends 23 u , 23 L and an outwardly waisted central section and is arranged co-axially around casing 21 which is similar to casing 1 of FIG. 1 . Sleeve 23 is secured at its upper end 23 u to the casing 21 by means of a mechanical clamp 28 . Towards the upper end 23 u of the sleeve, a pair of seal members 25 are also provided in the form of O-rings to provide a pressure tight connection between the upper end of the sleeve 23 u and the exterior of the casing 21 . Sleeve 23 has a lower end 23 L which is provided with a pair of sliding O-ring seals 27 .
[0064] The exterior of the casing 21 in the region of the seals 25 , 27 is preferably prepared by machining to improve the surface condition thereby achieving a more reliable connection between the seals 25 , 27 and the exterior of the casing 21 .
[0065] Upper end 23 u along with seals 25 and lower end of sleeve 23 L along with sliding seals 27 , waisted central section of sleeve 23 c and exterior of casing 21 define a chamber 26 . Sidewall of casing 21 is provided with circumferential equispaced ports 22 through its sidewall which permits fluid communication between the interior of casing 21 and the chamber 26 .
[0066] Chamber 26 can be filled with pressurised fluid such as hydraulic fluid to cause expansion of the waisted central section of the sleeve member 23 c in the radially outward direction, which causes simultaneous upwards movement of the sliding seals 27 , which has the advantage over the first embodiment of the sleeve 3 that the thickness of the sidewall of the outwardly waisted central section 23 c is not further thinned by the radially outwards expansion. However any such upwards movement should be restricted such that the ports 22 L, 22 u in the sidewall of casing 21 remain within chamber 26 .
[0067] A further embodiment of apparatus 30 in accordance with the present invention is shown in FIG. 3 , where the apparatus 30 is arranged in a similar manner to the apparatus 10 , 20 of FIGS. 1 and 2 . However, sleeve 33 of FIG. 3 is attached to casing 31 at both the upper end 33 u and lower end 33 L by clamps 39 . Clamps 39 are provided to hold the ends of sleeve 33 in position to prevent the sleeve 33 becoming dislodged when the casing 31 is run into the wellbore. Clamp 39 at the upper end 33 u of the sleeve will allow sleeve 33 to move in a downward direction enabling expansion thereof. However upwards movement of the upper end 33 u is prevented by clamp 39 which acts as an impediment. Similarly, clamp 39 at the lower sleeve end 33 L prevents downward movement, but will permit the lower sleeve end 33 L to move upwardly. The clamps 39 also ensure that the sleeve 33 maintains the correct position in relation to the ports 32 . Additionally, the clamps 39 maintain the sleeve in position over a section of casing 31 with prepared external surfaces. The surfaces can be prepared by machining and optimise the effectiveness of the two pairs of seals 35 .
[0068] A further and preferred embodiment of an isolation barrier apparatus 40 in accordance with the present invention is shown in FIG. 7 , where the apparatus 40 is arranged in a similar manner to the apparatus 10 , 20 , 30 of FIGS. 1, 2 and 3 , although the clamps for securing one or both ends of the sleeve 43 to the casing/liner 41 are not shown in FIG. 7 . In FIG. 7 , the apparatus 40 comprises a casing or liner 41 provided with one port 42 in its sidewall (or more likely a number of ports 41 circumferentially equi-spaced through the sidewall but only one of which is seen in FIG. 7 ).
[0069] Casing or liner 41 is located coaxially within sleeve 43 which comprises an inwardly waisted central section 43 c having a relatively thin sidewall thickness, such that the central section 43 c is either in contact with, or is close to contact with the outer circumference of the casing 41 . However, each end 43 u , 43 L of the central section 43 c is bowed outwardly in order to provide scope for hydraulic expansion of the sleeve 43 as will be subsequently described; furthermore, this arrangement provides a number of further advantages including reducing the outer diameter of the apparatus which eases running in of the apparatus into the borehole 79 and also provides a radial space within which a compliant material/sealant 75 and outer thin sleeve 77 is provided.
[0070] Accordingly, the inner surface of the initially inwardly waisted section 43 c , the inner surfaces of the bowed out ends 43 u , 43 L and the exterior of the casing/liner 41 define a chamber 46 . Port(s) 42 permit fluid communication between the interior or throughbore of the casing/liner 41 and chamber 46 .
[0071] Upper 45 u and lower 45 L O-ring seals are provided as before and perform the same function.
[0072] However, the apparatus 40 of FIG. 7 comprises a further enhancement over the previously described embodiments in that a compliant material/sealant 75 placed around the expandable diameter of the central section of the outer sleeve 43 c . A further concentric sleeve 77 formed of thin metal construction (approximately 1-2 mm in thickness) is placed around the compliant material/sealant 75 to effectively sandwich the compliant material/sealant 75 between the existing outer sleeve 43 c and the thin metal sleeve 77 . The thin metal sleeve 77 can be seal welded or clamped to the outer sleeve 43 c at each end to provide a closed envelope or closed chamber for the compliant material/sealant 75 within.
[0073] FIG. 10 shows a yet further enhanced isolation barrier apparatus 50 and which is identical to the apparatus 40 of FIG. 7 and components of the apparatus 50 which are similar to components of the apparatus 40 are denoted with the reference numeral pre-fix 5 - instead of 4 -. However, the apparatus 50 differs from apparatus 40 by the addition of holes or perforations 89 provided around the circumference of, and through the sidewall of, the thin metal sleeve 87 to permit the compliant material/sealant 85 to be extruded through such holes or perforations 89 when the sleeves 53 c , 87 are forced against the borehole wall 79 w as a result of the hydraulic expansion of the outer sleeve 53 c , as will be subsequently described. Furthermore, the compliant material 85 used in this embodiment 50 is specifically formulated to act as a sealant.
[0074] The material for the compliant material/sealant 75 is required to be sufficiently viscous to withstand removal and/or erosion from any fluid bypass during the hydraulic expansion of the outer sleeve 43 c and resulting creation of the isolation barrier (which will be described subsequently). Preferably, the compliant material/sealant 75 will stiffen and set when extruded into, and exposed to, wellbore fluid temperatures. A suitable material 75 may be unvulcanised (green) elastomer which when extruded through small ports undergo a shearing effect, in a manner similar to transfer moulding, which will further promote the setting of the sealant 75 . Chemical sealants, adhesives, lost circulation type fluids and specially developed pressure sealing crosslinked polymers are other possible materials 75 .
[0075] Isolation barrier apparatus 10 , 20 , or 30 is conveyed into the liner or borehole by any suitable means, such as incorporating the apparatus into a casing or liner string and running the string into the wellbore until it reaches the location within the liner or borehole at which operation of the apparatus 10 , 20 , 30 is intended. This location is normally within the liner or borehole at a position where the sleeve 3 , 23 , 33 is to be expanded in order to, for example, isolate the section of borehole (or if present, casing/liner) located above the sleeve 3 , 23 , 33 from that below in order to provide zonal isolation.
[0076] Expansion of the sleeve member 3 , 23 , 33 can be effected by a hydraulic expansion tool such as that shown in FIG. 4 . FIG. 4 shows tool 140 inserted into the casing section 31 shown in FIG. 3 . Once the casing 31 reaches its intended location, tool 140 can be run into the casing string from surface by means of a drillpipe string or other suitable method. The tool 140 is provided with upper and lower seal means 145 , which are operable to radially expand to seal against the inner surface of the casing section 31 at a pair of spaced apart locations in order to isolate an internal portion of casing 31 located between the seals 145 ; it should be noted that said isolated portion includes the fluid ports 32 . Tool 140 is also provided with an aperture 142 in fluid communication with the interior of the casing 31 .
[0077] To operate the tool 140 , seal means 145 are actuated from the surface (in a situation where drillpipe or coiled tubing is used) to isolate the portion of casing. Fluid, which may be hydraulic fluid, is then pumped under pressure through the coiled tubing or drillpipe such that the pressurised fluid flows through tool aperture 142 and then via ports 32 into chamber 36 .
[0078] A detailed description of the operation of such an expander tool 140 is described in UK Patent application no. GB0403082.1 (now published under UK Patent Publication number GB2398312) in relation to the packer tool 112 shown in FIG. 27 with suitable modifications thereto, where the seal means 145 could be provided by suitably modified seal assemblies 214 , 215 of GB0403082.1, the disclosure of which is incorporated herein by reference. The entire disclosure of GB0403082.1 is incorporated herein by reference.
[0079] Tool 140 would operate in a similar manner when inserted into casing 1 , 21 of FIGS. 1 and 2 . In the case where wireline is used to convey tool 140 into the borehole, a pump motor is operated to pump fluid from a hydraulic fluid reservoir into chambers 6 , 26 , 36 through aperture 142 via ports 2 , 22 , 32 . The increase in pressure then causes the sleeve 3 , 23 , 33 to move radially outwardly and seal against a portion of the inner circumference of the adjacent pipe (not shown), casing or liner section (not shown) or borehole 153 . The pressure within the chambers 6 , 26 , 36 continues to increase such that the sleeve 3 , 23 , 33 initially experience elastic expansion followed by plastic deformation. The sleeve 3 , 23 , 33 expands radially outwardly beyond its yield point, undergoing plastic deformation until the sleeve 3 , 23 , 33 bears against the inner surface of the liner or borehole as shown in FIG. 5 . If desired, the pressurised fluid within the chambers 6 , 26 , 36 can be bled off following plastic deformation of the sleeve 3 , 23 , 33 .
[0080] Alternatively the increase of pressure within chambers 6 , 26 , 36 , can be maintained such that the sleeve 3 , 23 , 33 continues to move outwardly against the adjacent pipe, casing or liner section such that the adjacent casing or liner section or pipe starts to experience elastic expansion. As the sleeve 3 , 23 , 33 makes contact with the tubular member or pipe, the pressure increases due to the resilience of the tubular member or pipe wall until the tubular member or pipe wall undergoes elastic deformation typically in the region of up to half a percent. The increase in setting pressure can be continued until a desired level of plastic expansion of the sleeves 3 , 23 , 33 have occurred and with the adjacent tubular member or pipe having undergone elastic expansion, when the pressure of the fluid is reduced the tubular member or pipe will maintain a compressive force inwardly on the plastically expanded sleeve 3 , 23 , 33 .
[0081] When the tubular member or pipe has undergone elastic deformation, pressure can be released. In this situation, sleeves 3 , 23 , 33 are securely held since they have undergone plastic deformation with the tubular member remaining elastically deformed.
[0082] FIG. 5 shows the casing 21 of FIG. 2 with sleeve 22 in its expanded configuration, bearing against the borehole wall 153 . Chamber 26 is filled with pressurised fluid which is prevented from exiting the chamber 26 by means of optional check valves (not shown) attached to ports 22 to maintain the sleeve 23 in an expanded condition; the check valves permit the flow of pressurised fluid from the throughbore 17 , 29 into the chamber 6 , 26 but prevent the flow of fluid in the reverse direction.
[0083] Pressurised chemical fluid can be pumped into chamber 26 to expand sleeve 22 . Once expanded the sleeve 22 may be maintained in position by check valves or the chemical fluid can be selected such that it sets in place after a certain period of time.
[0084] Alternatively, the ports 22 may be provided with a burst disks (not shown) therein, which will prevent fluid flow through the ports 22 until an operator intentionally ruptures the disks by applying hydraulic fluid pressure from the throughbore 17 , 29 to the inner face of the disk until the pressure is greater than the rated strength of the disk.
[0085] FIG. 6 shows a sequence for expanding two sleeve members. Different formations are indicated by reference numerals 180 a - e.
[0086] FIG. 6 a shows the embodiment where a perforated liner/casing 171 is attached at its upper end by any suitable means such as a liner hanger to the lower end of a cemented casing 160 . Liner 171 is provided with two sleeves 173 u , 173 L sealed thereto and similar to those previously described.
[0087] FIG. 6 b shows the perforated liner 171 of FIG. 6 a in a borehole 163 with a hydraulic expansion tool 190 inserted therein.
[0088] Activation of the hydraulic expansion tool 190 increases the pressure in the chambers defined by the sleeves 173 such that the sleeves expand outwardly as shown in FIG. 6 c . Thus, the sleeves 173 u , 173 L isolate formation 180 b (which may be a hydrocarbon producing zone) from the zones above and below 180 a , 180 c to 180 e (which may be, for example water producing zones) and thus provide a means of achieving zonal isolation.
[0089] As shown in FIG. 7 , the apparatus 40 complete with the additional compliant material 75 sandwiched between the thin metal sleeve 77 on the outside and the outer (outer to the casing 41 ) sleeve 43 c is run into position in the open hole section 79 to be isolated in the same manner as the previously described embodiments 10 , 20 and 30 . The hydraulic expansion tool (not shown in FIGS. 7 to 9 b ) is run into the well through the casing 41 bore in the same manner as the previously described embodiments 10 , 20 and 30 , and the outer sleeve 43 c is pressured up via the communication port 42 as previously described for the other embodiments. In this case however, when the outer sleeve 43 c expands, both the compliant material 75 and thin metal sleeve 77 will be forced to move outwardly along with the outer sleeve 43 c and will be forced into contact with the open hole 79 . As the thin metal sleeve 77 contacts the inner wall 79 of the open hole 79 it will conform to the irregularities of the borehole wall 79 w , since the compliant material 75 beneath it takes up the annular variances between the less compliant outer sleeve 43 c and the more compliant thin metal sleeve 77 . As the volume of compliant material 75 remains unchanged once all irregularities are filled, the contact stresses between the thin metal sleeve 77 and the wall 79 w will increase as the activating pressure provided by the hydraulic expansion tool is increased. This has the advantage of providing a metal to open hole seal that conforms more closely to the borehole wall 79 w variations than the bare outer sleeve 43 c , the overall effect of which should improve the effectiveness of the isolation barrier apparatus 40 .
[0090] The apparatus 50 is run into position in the same manner as the previously described embodiments 10 , 20 , 30 and 40 .
[0091] When the outer sleeve 53 c is pressured up in the same manner as previously described, the thin metal sleeve 87 is once again forced against the borehole wall 79 w . As this happens, the annular volume between the thin metal sleeve 87 and the outer sleeve 53 c will decrease, which causes the compliant material/sealant 85 to be extruded out through the holes/perforations 89 in the thin metal sleeve 87 and to be squeezed into the remaining annular space between the thin metal sleeve 87 and the borehole wall 79 w . In this way, any deep irregularities in the borehole wall 79 w can be filled with the compliant material/sealant 85 . As the sealant 85 sets or cures, it should create a more effective fluid seal and hence an improved isolation barrier can be achieved.
[0092] Modifications and improvements may be made to the embodiments hereinbefore described without departing from the scope of the invention. | An apparatus and method, particularly useful for isolating zones in a hydrocarbon wellbore. The apparatus includes a tubular section, such as a length of casing or liner tubular, arranged to be run into and secured within the wellbore which may be open hole or already cased. At least one sleeve member is positioned on the exterior of the tubular section and is sealed thereto. A pressure control device, which typically consists of a pressurised hydraulic fluid delivery device, can be used to increase the pressure within the sleeve member to cause the sleeve member to move outwardly and bear against an inner wall of the wellbore. | 4 |
TECHNICAL FIELD
[0001] The present invention relates to processing aids for polyolefins and polyolefin compositions containing the same. More specifically, the present invention relates to a composition containing a processing aid that is suitably used for processing of melt-fabricable polymers.
BACKGROUND ART
[0002] Melt-fabricable polymers need to be extrusion-molded at a high extrusion rate upon processing thereof with an aim of achieving higher productivity and lower cost. Melt-fabricable polymer compositions, however, surely have a critical shear rate. If the extrusion rate is higher than the critical shear rate, the surface becomes roughened (phenomenon called melt fracture), and the resulting molded articles are not satisfactory.
[0003] A molding method with a higher molding temperature is one example of a method that can achieve a higher extrusion rate and improve the extruding properties while preventing occurrence of melt fracture, thereby solving the above problem. However, high-temperature molding causes pyrolysis of melt-fabricable polymers, which raises other problems such as reduction in mechanical properties of molded articles and coloring of molded articles. In addition, the melt-fabricable polymer has a lower melt viscosity to suffer sagging or deformation before being cooled and solidified. This impairs the dimensional accuracy of molded articles.
[0004] Patent Literature 1 discloses, as another method, a method of producing an extrudable composition including the step of simultaneously mixing i) a first fluoroelastomer that has a first Mooney viscosity ML(1+10) at 121° C. determined in conformity with ASTM D1646 in an amount of 0.001 to 10 wt % based on the total weight of the extrudable composition, ii) a second fluoroelastomer having a second Mooney viscosity ML(1+10) at 121° C. determined in conformity with ASTM D1646 in an amount of 0.001 to 10 wt % based on the total weight of the extrudable composition, and iii) a non-fluorinated melt-fabricable polymer, with a difference between the first and second Mooney viscosities of at least 15.
[0005] Patent Literature 2 discloses a method including the steps of: preparing a melt-fabricable polymer composition that contains a melt-fabricable thermoplastic host polymer and an effective amount of an additive composition for processing that contains a specific multimode fluoropolymer; mixing the additive composition for processing and the host polymer for a time enough for thorough mixing of them; and melt-fabricating the polymer composition.
[0006] The following documents disclose techniques using a fluoropolymer as a processing aid. Patent Literature 3 discloses an extrudable composition containing a thermoplastic hydrocarbon polymer, a poly(oxyalkylene) polymer, and a fluorocarbon polymer. Patent Literature 4 discloses an extrudable composition containing a resin blend that contains a metallocene linear low-density polyethylene resin and a low-density polyethylene resin, a fluoroelastomer that has a Mooney viscosity ML(1+10) at 121° C. of 30 to 60, and a surfactant. Patent Literature 5 discloses a processing aid containing a fluoropolymer that has an acid value of 0.5 KOHmg/g or higher.
[0007] These disclosed techniques, however, still fail to achieve the effect of preventing occurrence of melt fracture under a high shear rate condition with a shear rate exceeding 800 sec −1 .
[0008] With an aim of providing a polymer that can give extrudates of high surface quality even extruded at a high rate and can be extruded at a low die pressure, and has a low melting temperature, Patent Literature 6 discloses a processing aid composition for hardly melt-fabricable polymers, essentially containing 2 to 95 parts by weight of a fluorocarbon copolymer and 98 to 5 parts by weight of a tetraflucroethylene homopolymer or of a copolymer of tetrafluoroethylene and a monomer copolymerizable with tetrafluoroethylene. If the fluorocarbon copolymer is crystalline, the copolymer is in a molten state at a temperature of melt-fabricating the hardly melt-fabricable polymer, and if it is amorphous, the temperature of melt-fabricating the hardly melt-fabricable polymer is higher than the glass transition temperature of the fluorocarbon copolymer. The tetrafluoroethylene homopolymer or the copolymer of tetrafluoroethylene and a monomer copolymerizable with tetrafluoroethylene contains fluorine atoms and hydrogen atoms in a mole ratio of at least 1:1 and is solid at the temperature of melt-fabricating the hardly melt-fabricable polymer.
[0009] Patent Literature 7 discloses a low-temperature-decomposable engineering plastic resin composition that can have improved molding processability because it can be molded, for example, at a reduced extrusion pressure and a reduced extrusion torque upon molding of a low-temperature-decomposable engineering plastic. The low-temperature-decomposable engineering plastic resin composition is prepared by compounding a low-temperature-decomposable engineering plastic having a melting point of 200° C. or lower and a decomposition temperature of 300° C. or lower and a fluororesin formed from a fluoropolymer in which at least one atom selected from the group consisting of a hydrogen atom, a chlorine atom, a bromine atom, and an iodine atom and a fluorine atom are bonded to a carbon atom of the main chain excluding the terminal carbon atom(s) and which is substantially free from a polar functional group reactive with the low-temperature-decomposable engineering plastic.
CITATION LIST
Patent Literature
[0010] Patent Literature 1: JP 4181042 B
[0011] Patent Literature 2: JP 2002-544358 T
[0012] Patent Literature 3: JP H02-70737 A
[0013] Patent Literature 4: JP 2007-510003 T
[0014] Patent Literature 5: WO 2011/025052
[0015] Patent Literature 6: U.S. Pat. No. 5,013,792 B
[0016] Patent Literature 7: WO 03/044088
SUMMARY OF INVENTION
Technical Problem
[0017] In consideration of the state of the art, the present invention provides a processing aid for polyolefins which enables disappearance of melt fracture occurred at the start of molding in a short time even when a polyolefin that is a melt-fabricable polymer is extrusion-molded at a high rate.
[0018] The present invention also provides a polyolefin composition containing such a processing aid for polyolefins and a specific polyolefin.
Solution to Problem
[0019] The present inventors intensively studied to find out that a combination of a processing aid for polyolefins containing a perfluoroelastomer and a specific polyolefin enables disappearance of melt fracture occurred at the start of molding in a short time even when a polyolefin blended with such a processing aid is extrusion-molded at a high shear rate. They also found out that addition of a small amount of the processing aid to a specific polyolefin enables dispersion of the processing aid in the form of particles in the polyolefin, with the processing aid having an average dispersed particle size in the polyolefin of 10 μm or smaller. This enables disappearance of melt fracture in an equal period of time in comparison with conventional techniques.
[0020] The present inventors thus arrived at a solution of the above problem, i.e., a polyolefin composition containing a processing aid for polyolefins that contains a perfluoroelastomer and a specific polyolefin. Thereby, the inventors have completed the present invention.
[0021] Specifically, the present invention relates to a processing aid for polyolefins including a perfluoroelastomer, the processing aid being intended to be used for extrusion-molding at least one polyolefin selected from the group consisting of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, metallocene linear low-density polyethylene, polypropylene, and polyvinyl chloride.
[0022] The perfluoroelastomer is preferably a copolymer of tetrafluoroethylene and at least one fluoromonomer selected from the group consisting of:
[0023] hexafluoropropylene;
[0024] a fluoromonomer represented by the formula (8):
[0000] CF 2 ═CF—ORf 81
[0000] wherein Rf 81 is a C1-C8 perfluoroalkyl group;
[0025] a fluoromonomer represented by the formula (10):
[0000] CF 2 ═CFOCF 2 ORf 101
[0000] wherein Rf 101 is a C1-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a C2-C6 linear or branched perfluorooxyalkyl group containing 1 to 3 oxygen atoms; and
[0026] a fluoromonomer represented by the formula (11):
[0000] CF 2 ═CFO(CF 2 CF(Y)O) m (CF 2 ) n F
[0000] wherein Y is a fluorine atom or a trifluoromethyl group; m is an integer of 1 to 4; and n is an integer of 1 to 4.
[0027] The perfluoroelastomer is preferably a copolymer of tetrafluoroethylene and a fluoromonomer represented by the formula (8):
[0000] CF 2 ═CF—ORf 81
[0000] wherein Rf 81 is a C1-C8 perfluoroalkyl group.
[0028] The perfluoroelastomer is preferably a copolymer of tetrafluoroethylene and perfluoro(methyl vinyl ether).
[0029] The processing aid for polyolefins of the present invention preferably further contains 1 to 99 wt % of at least one surfactant selected from the group consisting of silicone-polyether copolymers, aliphatic polyesters, aromatic polyesters, polyether polyols, amine oxides, carboxylic acids, aliphatic esters, and poly(oxyalkylenes).
[0030] The present invention also relates to a polyolefin composition including a processing aid for polyolefins, and a polyolefin, the processing aid for polyolefins containing a perfluoroelastomer, the polyolefin being at least one selected from the group consisting of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, metallocene linear low-density polyethylene, polypropylene, and polyvinyl chloride.
[0031] The perfluoroelastomer is preferably a copolymer of tetrafluoroethylene and at least one fluoromonomer selected from the group consisting of:
[0032] hexafluoropropylene;
[0033] a fluoromonomer represented by the formula (8):
[0000] CF 2 ═CF—ORf 81
[0000] wherein Rf 81 is a C1-C8 perfluoroalkyl group;
a fluoromonomer represented by the formula (10):
[0000] CF 2 ═CFOCF 2 ORf 101
[0000] wherein Rf 101 is a C1-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a C2-C6 linear or branched perfluorooxyalkyl group containing 1 to 3 oxygen atoms; and
[0034] a fluoromonomer represented by the formula (11):
[0000] CF 2 ═CFO(CF 2 CF(Y)O) m (CF 2 ) n F
[0000] wherein Y is a fluorine atom or a trifluoromethyl group; m is an integer of 1 to 4; and n is an integer of 1 to 4.
[0035] The perfluoroelastomer is preferably a copolymer of tetrafluoroethylene and a fluoromonomer represented by the formula (8):
[0000] CF 2 ═CF—ORf 81
[0000] wherein Rf 81 is a C1-C8 perfluoroalkyl group.
[0036] The perfluoroelastomer is preferably a copolymer of tetrafluoroethylene and perfluoro(methyl vinyl ether).
[0037] The processing aid for polyolefins preferably further contains 1 to 99 wt % of at least one surfactant selected from the group consisting of silicone-polyether copolymers, aliphatic polyesters, aromatic polyesters, polyether polyols, amine oxides, carboxylic acids, aliphatic esters, and poly(oxyalkylenes).
[0038] The processing aid for polyolefins is preferably present in an amount of 0.0005 to 10 wt % based on the total weight of the polyolefin composition.
[0039] The present invention is specifically described below.
[0040] The present invention relates to a processing aid for polyolefins including a perfluoroelastomer, the processing aid being intended to be used for extrusion-molding at least one polyolefin selected from the group consisting of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, metallocene linear low-density polyethylene, polypropylene, and polyvinyl chloride.
[0041] With this configuration, even when the polyolefin composition prepared by adding the processing aid for polyolefins of the present invention to a specific polyolefin is extrusion-molded at a high shear rate, the melt fracture occurred at the start of molding disappears in a short time.
[0042] The perfluoroelastomer refers to a fluoropolymer containing 96 to 100 mol % of a polymerized unit based on a perfluoromonomer and 0 to 4 mol % of a polymerized unit based on a monomer that provides a cross-linking site, in all the polymerized units.
[0043] The perfluoroelastomer is preferably amorphous. The term “amorphous” means that the melting peak (AH) appearing in the DSC (temperature-increasing rate: 10° C./min) is 2.0 J/g or lower.
[0044] The fluoromonomer constituting the perfluoroelastomer preferably has at least one double bond. The fluoromonomer is preferably a perfluoromonomer.
[0045] The perfluoromonomer is preferably at least one selected from the group consisting of:
[0046] tetrafluoroethylene (TFE);
[0047] hexafluoropropylene (HFP);
[0048] a fluoromonomer represented by the formula (8):
[0000] CF 2 ═CF—ORf 81
[0000] wherein Rf 81 is a C1-C8 perfluoroalkyl group;
[0049] a fluoromonomer represented by the formula (10):
[0000] CF 2 ═CFOCF 2 ORf 101
[0000] wherein Rf 101 is a C1-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a C2-C6 linear or branched perfluorooxyalkyl group containing 1 to 3 oxygen atoms; and
[0050] a fluoromonomer represented by the formula (11):
[0000] CF 2 ═CFO(CF 2 CF(Y)O) m (CF 2 ) n F
[0000] wherein Y is a fluorine atom or a trifluoromethyl group; m is an integer of 1 to 4; and n is an integer of 1 to 4.
[0051] Examples of the fluoromonomer represented by the formula (8) include perfluoro(alkyl vinyl ethers)(PAVE). The fluoromonomer is preferably at least one selected from the group consisting of perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether), and perfluoro(propyl vinyl ether), more preferably perfluoro(methyl vinyl ether).
[0052] The fluoromonomer represented by the formula (10) is preferably at least one selected from the group consisting of CF 2 ═CFOCF 2 OCF 3 , CF 2 ═CFOCF 2 OCF 2 CF 3 , and CF 2 ═CFOCF 2 OCF 2 CF 2 OCF 3 .
[0053] The fluoromonomer represented by the formula (11) is preferably at least one selected from the group consisting of CF 2 ═CFOCF 2 CF(CF 3 )O(CF 2 ) 3 F, CF 2 ═CFO(CF 2 CF(CF 3 )O) 2 (CF 2 ) 3 F, and CF 2 ═CFO(CF 2 CF(CF 3 )O) 2 (CF 2 ) 2 F.
[0054] The perfluoroelastomer may be prepared by polymerizing the perfluoromonomer and a monomer that provides a cross-linking site.
[0055] The monomer that provides a cross-linking site is preferably at least one selected from the group consisting of:
[0056] a fluoromonomer represented by the formula (12):
[0000] CX 3 2 ═CX 3 —R f 121 CHR 121 X 4
[0000] wherein X 3 is a hydrogen atom, a fluorine atom, or CH 3 ; R f 121 is a fluoroalkylene group, a perfluoroalkylene group, a fluoro(poly)oxyalkylene group, or a perfluoro(poly)oxyalkylene group; R 121 is a hydrogen atom or CH 3 ; and X 4 is a iodine atom or a bromine atom;
[0057] a fluoromonomer represented by the formula (13):
[0000] CX 3 2 ═CX 3 —R f 131 X 4
[0000] wherein X 3 is a hydrogen atom, a fluorine atom, or CH 3 ; R f 131 is a fluoroalkylene group, a perfluoroalkylene group, a fluoropolyoxyalkylene group, or a perfluoropolyoxyalkylene group; and X 4 is a iodine atom or a bromine atom;
[0058] a fluoromonomer represented by the formula (14):
[0000] CF 2 ═CFO(CF 2 CF(CF 3 )O) m (CF 2 ) n —X 5
[0000] wherein m is an integer of 0 to 5; n is an integer of 1 to 3; X 5 is a cyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom, a bromine atom, or —CH 2 I;
[0059] a fluoromonomer represented by the formula (15):
[0000] CH 2 ═CFCF 2 O(CF(CF 3 )CF 2 O) m (CF(CF 3 )) n —X 6
[0000] wherein m is an integer of 0 to 5; n is an integer of 1 to 3; X 6 is a cyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom, a bromine atom, or —CH 2 OH; and
[0060] a monomer represented by the formula (16):
[0000] CR 162 R 163 ═CR 164 —Z—CR 165 ═CR 166 R 167
[0000] wherein R 162 , R 163 , R 164 , R 165 , R 166 , and R 167 may be the same as or different from each other, and are each a hydrogen atom or a C1-C5 alkyl group; Z is a linear or branched C1-C18 alkylene group which may optionally have an oxygen atom, a C3-C18 cycloalkylene group, a C1-C10 alkylene or oxyalkylene group which is at least partly fluorinated, or a (per)fluoropolyoxyalkylene group represented by the formula: -(Q) p -CF 2 O—(CF 2 CF 2 O) m (CF 2 O)n-CF 2 -(Q) p - (wherein Q is an alkylene or oxyalkylene group; p is 0 or 1; and m/n is 0.2 to 5), and having a molecular weight of 500 to 10000.
[0061] X 3 is preferably a fluorine atom, R f 121 and R f 131 are each preferably a C1-C5 perfluoroalkylene group. R 121 is preferably a hydrogen atom.
[0062] The monomer that provides a cross-linking site is preferably at least one selected from the group consisting of CF 2 ═CFOCF 2 CF(CF 3 )OCF 2 CF 2 CN, CF 2 ═CFOCF 2 CE(CF 3 )OCF 2 CF 2 COOH, CF 2 ═CFOCF 2 CF(CF 3 )OCF 2 CF 2 CH 2 I, CF 2 ═CFOCF 2 CF 2 CH 2 I, CH 2 ═CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )CN, CH 2 ═CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )COOH, CH 2 ═CFCF 2 OCF(CF 3 )CF 2 OCF(CF 3 )CH 2 OH, CH 2 ═CHCF 2 CF 2 I, CH 2 ═CH(CF 2 ) 2 CH═CH 2 , CH 2 ═CH(CF 2 ) 6 CH═CH 2 , and CF 2 ═CFO(CF 2 ) 5 CN, more preferably at least one selected from the group consisting of CF 2 ═CFOCF 2 CF(CF 3 )OCF 2 CF 2 CN and CF 2 ═CFOCF 2 CF 2 CH 2 I.
[0063] The perfluoroelastomer is preferably prepared by polymerizing a perfluoromonomer alone or monomers consisting of a perfluoromonomer and a monomer that provides a cross-linking site. Polymerization of a perfluoromonomer alone or monomers consisting of a perfluoromonomer and a monomer that provides a cross-linking site enables production of particles of the perfluoroelastomer.
[0064] The perfluoroelastomer is preferably a copolymer of tetrafluoroethylene (TFE) and at least one fluoromonomer selected from the group consisting of:
[0065] hexafluoropropylene (HFP);
[0066] a fluoromonomer represented by the formula (8):
[0000] CF 2 ═CF—ORf 81
[0000] wherein Rf 81 is a C1-C8 perfluoroalkyl group;
[0067] a fluoromonomer represented by the formula (10):
[0000] CF 2 ═CFOCF 2 ORf 101
[0000] wherein Rf 101 is a C1-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a C2-C6 linear or branched perfluorooxyalkyl group containing 1 to 3 oxygen atoms; and
[0068] a fluoromonomer represented by the formula (11):
[0000] CF 2 ═CFO(CF 2 CF(Y)O) m (CF 2 ) n F
[0000] wherein Y is a fluorine atom or a trifluoromethyl group; m is an integer of 1 to 4; and n is an integer of 1 to 4.
[0069] The perfluoroelastomer is preferably a perfluoroelastomer containing TFE, for example, at least one selected from the group consisting of a copolymer of TFE and a fluoromonomer represented by the formula (8), (10), or (11), and a copolymer of TFE, a fluoromonomer represented by the formula (8), (10), or (11), and a monomer that provides a cross-linking site.
[0070] In the case of the TFE/PAVE copolymer, the compositional ratio is preferably 45 to 90/10 to 55 (mol %), more preferably 55 to 80/20 to 45, still more preferably 55 to 70/30 to 45.
[0071] In the case of the copolymer of TFE/PAVE/monomer that provides a cross-linking site, the compositional ratio is preferably 45 to 89.9/10 to 54.9/0.01 to 4 (mol %), more preferably 55 to 79.9/20 to 44.9/0.1 to 3.5, still more preferably 55 to 69.8/30 to 44.8/0.2 to 3.
[0072] In the case of the copolymer of TFE/C4-C12 fluoromonomer represented by the formula (8), (10), or (11), the compositional ratio is preferably 50 to 90/10 to 50 (mol %), more preferably 60 to 88/12 to 40, still more preferably 65 to 85/15 to 35.
[0073] In the case of the copolymer of TFE/C4-C12 fluoromonomer represented by the formula (8), (10), or (11)/monomer that provides a cross-linking site, the compositional ratio is preferably 50 to 89.9/10 to 49.9/0.01 to 4 (mol %), more preferably 60 to 87.9/12 to 39.9/0.1 to 3.5, still more preferably 65 to 84.8/15 to 34.8/0.2 to 3.
[0074] If the compositional ratio is beyond the above ranges, the copolymer fails to have rubber elasticity and tends to have resin-like properties.
[0075] The monomer that provides a cross-linking site is as described above.
[0076] The perfluoroelastomer is preferably at least one selected from the group consisting of a copolymer of TFE/fluoromonomer represented by the formula (11), a copolymer of TFE/fluoromonomer represented by the formula (11)/monomer that provides a cross-linking site, a copolymer of TFE/fluoromonomer represented by the formula (8), and a copolymer of TFE/fluoromonomer represented by the formula (8)/monomer that provides a cross-linking site.
[0077] Examples of the perfluoroelastomer also include perfluoroelastomers disclosed in WO 97/24381, JP S61-57324 B, JP H04-81608 B, and JP H05-13961 B.
[0078] In particular, the perfluoroelastomer is preferably a copolymer of TFE/fluoromonomer represented by the formula (8).
[0079] The processing aid may contain two or more of the above perfluoroelastomers, and preferably contains a copolymer of TFE/fluoromonomer represented by the formula (8) alone, more preferably a copolymer of TFE/perfluoro(methyl vinyl ether).
[0080] The perfluoroelastomer preferably has at least one group selected from the group consisting of —CONH 2 , —OCOOR (wherein R is a C1-C6 alkyl group), —CH 2 OH, —COF, and —COOH at an end of the main chain. The perfluoroelastomer having such a functional group at an end of the main chain improves the affinity between the metal surface of a die and the processing aid. Accordingly, when used for a processing aid, the perfluoroelastomer improves the pressure-decreasing rate and increases the amount of pressure decrease.
[0081] The functional group can be introduced into the perfluoroelastomer by appropriately selecting a polymerization initiator or a monomer having the functional group at a side chain used in the polymerization.
[0082] R in the group represented by —OCOOR is a C1-C6 alkyl group, preferably a C1-C5 alkyl group, more preferably a C1-C4 alkyl group. R is still more preferably a methyl group, an ethyl group, an n-propyl group, or an iso-propyl group.
[0083] The perfluoroelastomer may have a cross-linking site but preferably does not contain a monomer unit that provides a cross-linking site because the presence of a cross-linking site leads to gelation, resulting in molding defects (e.g., molded article with fish eyes).
[0084] The monomer unit composition of the perfluoroelastomer can be determined by NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis in any appropriate combination in accordance with the types of monomers.
[0085] The perfluoroelastomer can be produced by any known polymerization method, such as suspension polymerization, solution polymerization, or emulsion polymerization, using any monomer that is to be a polymerized unit of the perfluoroelastomer, a polymerization initiator, a chain transfer agent, a surfactant, an aqueous medium, and other components.
[0086] In the polymerization, the conditions such as temperature and pressure and use of additives such as a polymerization initiator may be appropriately selected in accordance with the composition or amount of the desired perfluoroelastomer.
[0087] Preferred among the polymerization methods is emulsion polymerization in which a surfactant is used. A wide variety of emulsifiers may be used in the emulsion polymerization, and a salt of a carboxylic acid having a fluorocarbon chain or a fluoropolyether chain is preferred in order to suppress a chain transfer reaction to emulsifier molecules which may occur during the polymerization. The amount of the emulsifier is preferably about 0.05 to 2 wt %, more preferably 0.2 to 1.5 wt % of the amount of water added.
[0088] If the perfluoroelastomer is a perfluoroelastomer aqueous dispersion produced by emulsion polymerization, for example, the perfluoroelastomer is preferably in the form of particles.
[0089] The perfluoroelastomer particles in the aqueous dispersion preferably have a volume average particle size of 0.1 to 700 nm. The perfluoroelastomer particles having a volume average particle size within the above range can be present stably in the aqueous dispersion.
[0090] The volume average particle size of the perfluoroelastomer particles is more preferably 1 nm or greater, still more preferably 10 nm or greater, and is more preferably 400 nm or smaller, still more preferably 200 nm or smaller.
[0091] The volume average particle size is determined by dynamic light scattering. The aqueous dispersion obtained by polymerization is diluted 10 times with pure water to provide an aqueous dispersion for particle size measurement. The particle size is measured from 70 measurement processes using ELSZ-1000S (Otsuka Electronics Co., Ltd.) at 25° C. The solvent (water) had a refractive index of 1.3328 and a viscosity of 0.8878. The average value of the volume distributions is defined as the volume average particle size.
[0092] The perfluoroelastomer particles contained in the perfluoroelastomer aqueous dispersion may be formed into a powder or crumb of the perfluoroelastomer by coagulation of the particles and dry-removal of the moisture contained in the resulting coagulated mass.
[0093] The coagulation is preferably performed by any known method such as addition of an inorganic salt (e.g., aluminum sulfate) or an inorganic acid, application of a mechanical shearing force, or freezing of the dispersion.
[0094] The drying may be performed by any method that can remove the moisture without deteriorating the perfluoroelastomer itself, and is usually a method performed at 50° C. to 150° C. for 5 to 100 hours. The drying may be performed in vacuo or with hot air at atmospheric pressure.
[0095] For excellent dispersibility in a polyolefin, the perfluoroelastomer preferably has a glass transition temperature of −70° C. or higher, more preferably −50° C. or higher, still more preferably −30° C. or higher. In order to achieve desired effects even in molding a polyolefin at low temperature, the glass transition temperature thereof is preferably 5° C. or lower, more preferably 0° C. or lower, still more preferably −3° C. or lower.
[0096] The glass transition temperature can be determined as the temperature indicated by the middle point of two intersections between each of the extended lines of the base lines before and after the secondary transition of the DSC curve and the tangent at the inflection point of the DSC curve. Here, the DSC curve can be obtained by heating 10 mg of a test sample at 10° C./min using a differential scanning calorimeter (DSC822e, Mettler-Toledo International Inc.).
[0097] For good heat resistance, the perfluoroelastomer preferably has a Mooney viscosity ML 1+20 at 170° C. of 10 or higher, more preferably 40 or higher, still more preferably 50 or higher. For good processability, the Mooney viscosity ML 1+20 at 170° C. is preferably 150 or lower, more preferably 120 or lower.
[0098] The Mooney viscosity can be determined at 100° C. or 170° C. using the MV2000E Mooney viscometer (Alpha Technologies Co.) in conformity with JIS K6300.
[0099] The amount of the perfluoroelastomer is preferably 1 to 100 wt % in the processing aid.
[0100] The processing aid for polyolefins of the present invention may contain an anti re-agglomerating agent.
[0101] Containing the anti re-agglomerating agent suppresses sticking of the perfluoroelastomer.
[0102] The anti re-agglomerating agent is preferably a powder of an inorganic compound. For example, the anti re-agglomerating agent is preferably a powder of any of inorganic compounds that are to be mentioned hereinbelow as examples of a filler, a colorant, or an acid acceptor.
[0103] The anti re-agglomerating agent may be any of those usually used as fillers, colorants, or acid acceptors.
[0104] Examples of the filler include barium sulfate, calcium carbonate, graphite, talc, and silica.
[0105] Examples of the colorant include metal oxides such as titanium oxide, iron oxide, and molybdenum oxide.
[0106] Examples of the acid acceptor include magnesium oxide, calcium oxide, and lead oxide.
[0107] The anti re-agglomerating agent is preferably any of the fillers. The anti re-agglomerating agent is more preferably at least one selected from the group consisting of talc, silica, and calcium carbonate.
[0108] The anti re-agglomerating agent is preferably a powder having an average particle size of 0.01 μm or greater and 50 μm or smaller. The average particle size of the powder is more preferably 0.05 μm or greater and 30 μm or smaller, still more preferably 0.1 μm or greater and 10 μm or smaller. The average particle size of the anti re-agglomerating agent is a value determined in conformity with ISO 13320-1.
[0109] The anti re-agglomerating agent may be surface-treated with a coupling agent, if necessary.
[0110] The amount of the anti re-agglomerating agent is preferably 1 to 30 parts by weight, more preferably 3 to 20 parts by weight, still more preferably 5 to 15 parts by weight, in 100 parts by weight of the perfluoroelastomer.
[0111] One anti re-agglomerating agent may be used alone or two or more anti re-agglomerating agents may be used in combination.
[0112] The processing aid for polyolefins of the present invention may further contain a surfactant.
[0113] Combination use of the perfluoroelastomer and a surfactant can further improve the performance of the perfluoroelastomer as a processing aid.
[0114] The surfactant is a compound having a lower melt viscosity than the perfluoroelastomer at a molding temperature. When contained in the polyolefin composition to be mentioned later, the surfactant is preferably a compound that has a lower melt viscosity than a melt-fabricable resin at a molding temperature and can wet the surface of the perfluoroelastomer.
[0115] The surfactant is preferably at least one compound selected from the group consisting of silicone-polyether copolymers, aliphatic polyesters, aromatic polyesters, polyether polyols, amine oxides, carboxylic acids, aliphatic esters, and poly(oxyalkylenes). More preferred among these are poly(oxyalkylenes).
[0116] Preferred among the poly(oxyalkylenes) is polyethylene glycol. The polyethylene glycol preferably has a number average molecular weight of 50 to 20000, more preferably 1000 to 15000, still more preferably 2000 to 9500.
[0117] The number average molecular weight of the polyethylene glycol is a value calculated from the hydroxyl value determined in conformity with JIS K0070.
[0118] Preferred among the aliphatic polyesters is polycaprolactone. The polycaprolactone preferably has a number average molecular weight of 1000 to 32000, more preferably 2000 to 10000, still more preferably 2000 to 4000.
[0119] The amount of the surfactant is preferably 1 to 99 wt %, more preferably 5 to 90 wt %, still more preferably 10 to 80 wt %, particularly preferably 20 to 70 wt %, in the processing aid. The amount of the surfactant is also preferably 50 wt % or more, more preferably not less than 50 wt %.
[0120] With a high molding temperature (about 280° C. or higher), the processing aid of the present invention preferably consists of a fluoroelastomer. With a molding temperature of about 250° C. or lower, the processing aid preferably contains a fluoroelastomer and a surfactant.
[0121] When the processing aid containing a perfluoroelastomer is added to a specific polyolefin to be mentioned later, the processing aid is dispersed in the form of particles in the specific polyolefin and the processing aid has an average dispersed particle size of 10 μm or smaller in the polyolefin. This enables disappearance of melt fracture in an equal period of time in comparison with conventional techniques.
[0122] Such a polyolefin composition that is a composition containing the aforementioned processing aid for polyolefins and a polyolefin, the processing aid for polyolefins containing a perfluoroelastomer, the polyolefin being at least one selected from the group consisting of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, metallocene linear low-density polyethylene, polypropylene, and polyvinyl chloride is also one aspect of the present invention.
[0123] The polyolefin in the polyolefin composition of the present invention is at least one selected from the group consisting of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), metallocene linear low-density polyethylene (mLLDPE), polypropylene (PP), and polyvinyl chloride (PVC).
[0124] The polyolefin is more preferably polyethylene or polypropylene, still more preferably polyethylene.
[0125] The polyolefin preferably has a melt-fabricable temperature of 100° C. to 350° C. The polyolefin may or may not have crystallizability.
[0126] The polyolefin, if having crystallizability, preferably has a melting point of 80° C. to 300° C., more preferably 100° C. to 200° C. A non-crystallizable polyolefin preferably has substantially the same fabricable temperature as a crystallizable polyolefin whose melting point range is known.
[0127] The melting point of a crystallizable polyolefin can be determined using a DSC device.
[0128] The polyolefin can be synthesized by any conventionally known method in accordance with the type thereof.
[0129] The polyolefin may be in any form such as powder, granules, or pellets. In order to efficiently melt the polyolefin and to disperse the processing aid for polyolefins, the polyolefin is preferably in the form of pellets in the polyolefin composition of the present invention.
[0130] The polyolefin composition of the present invention is a dispersion of the processing aid for polyolefins in the form of fine particles in the polyolefin. The polyolefin composition in such a form can prevent occurrence of molding defects such as visually observable contaminants in thin molded articles and poor surface smoothness.
[0131] In the polyolefin composition of the present invention, the processing aid for polyolefins in the polyolefin has an average dispersed particle size of 10 μm or smaller. The processing aid for polyolefins having an average dispersed particle size of 10 μm or smaller can more homogeneously attach to the die surface.
[0132] The average dispersed particle size of the processing aid for polyolefins is preferably 7 μm or smaller, more preferably 5 μm or smaller. The average dispersed particle size thereof is still more preferably 3 μm or smaller.
[0133] The lower limit of the average dispersed particle size may be any value, and may be 0.1 μm.
[0134] The average dispersed particle size of the processing aid for polyolefins can be determined as follows. Specifically, the polyolefin composition of the present invention is microscopically observed using a confocal laser microscope. Alternatively, an ultrathin slice is cut out of a pressed sheet or a pellet prepared from the polyolefin composition of the present invention, and is microscopically observed using a transmission electron microscope (TEM) or a reflected light microscope. Then, the resulting image is binarized using an optical analyzer.
[0135] The polyolefin composition of the present invention may further contain any other additional components, if necessary, in addition to the processing aid for polyolefins and a polyolefin.
[0136] Examples of the additional components include ultraviolet absorbers; flame retardants; reinforcing materials such as glass fibers and glass powder; stabilizers such as minerals and flakes; lubricants such as silicone oil and molybdenum disulfide; pigments such as titanium dioxide and red iron oxide; conductive agents such as carbon black; impact-resistance improvers such as rubber; antioxidants such as hindered phenol antioxidants and phosphorus antioxidants; core-forming agents such as metal salts and acetals of sorbitol; and other additives recorded in the positive list that is formulated as voluntary standards by Japan Hygienic Olefin And Styrene Plastics Association.
[0137] The polyolefin composition of the present invention preferably contains 0.0005 to 10 wt % of the processing aid for polyolefins based on the total weight of the composition. The polyolefin composition of the present invention containing the processing aid for polyolefins at a proportion within the above range can be used as a molding material for producing molded articles, or can be processed into a masterbatch for processing aids. The amount of the processing aid for polyolefins in the polyolefin composition of the present invention is preferably 0.001 to 7 wt %, more preferably 0.0025 to 5 wt % based on the total weight of the composition.
[0138] Especially when the polyolefin composition of the present invention is used as a molding material, the wt % ratio of the perfluoroelastomer to the polyolefin in the polyolefin composition of the present invention is preferably 1 to 0.00005 wt %. The wt % ratio thereof is more preferably 0.5 to 0.0001 wt %, still more preferably 0.2 to 0.005 wt %.
[0139] The masterbatch for processing aids prepared from the polyolefin composition of the present invention can be suitably used as a processing aid in molding polyolefins.
[0140] In the masterbatch for processing aids prepared from the polyolefin composition of the present invention, the processing aid for polyolefins is uniformly dispersed in the polyolefin. Thus, adding the masterbatch in molding polyolefins can improve the processability in molding polyolefins, such as decreases in extrusion torque and extrusion pressure.
[0141] Examples of the polyolefin include the same polyolefins as mentioned above, and the polyolefin is preferably polyethylene or polypropylene, more preferably polyethylene.
[0142] The masterbatch for processing aids may be in any form such as powder, granules, or pellets. In order to keep the processing aid for polyolefins of the present invention in the state of being finely dispersed in the polyolefin, the masterbatch is preferably in the form of pellets obtained by a melt-kneading process.
[0143] The melt-kneading is preferably performed at an extrusion temperature higher than the melting point of the perfluoroelastomer. The extrusion temperature is preferably not lower than the melting point, and the extrusion temperature is more preferably 10° C. or more higher than the melting point.
[0144] For easy melt-fabrication, the wt % ratio of the perfluoroelastomer to the polyolefin in the masterbatch for processing aids is preferably 0.05 to 10 wt %, more preferably 0.1 to 5 wt %.
[0145] The masterbatch for processing aids may further contain any other additional components, if necessary, in addition to the processing aid for polyolefins and the polyolefin.
[0146] The additional components may be any components, and examples thereof include the same components as those to be contained in the composition of the present invention.
[0147] The masterbatch for processing aids can be obtained by kneading, at 100° C. to 350° C., a matter prepared by adding the perfluoroelastomer and other components as desired to the polyolefin.
[0148] Such a use, in molding polyolefins, of the composition containing a processing aid for polyolefins and a polyolefin, the processing aid for polyolefins containing a perfluoroelastomer, the polyolefin being at least one selected from the group consisting of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, metallocene linear low-density polyethylene, polypropylene, and polyvinyl chloride, is also one preferred embodiment of the present invention.
[0149] The present invention also relates to a molded article obtained by molding the aforementioned polyolefin composition of the present invention.
[0150] The molding may be performed by preparing the polyolefin composition of the present invention in advance, putting the composition into a molding device, and then melting and extruding the composition, or may be performed by putting the perfluoroelastomer, the polyolefin, and other components as desired into a molding device at once, and then melting and extruding the mixture, or may be performed by putting the masterbatch for processing aids and the polyolefin into a molding device at once, and then melting and extruding the mixture.
[0151] The polyolefin composition may be molded by any method such as extrusion molding, injection molding, or blow molding. In order to effectively enjoy the molding processability, extrusion molding is preferred.
[0152] The molding may be performed under any conditions, and the conditions may be appropriately adjusted in accordance with the composition and amount of the polyolefin composition to be used, the shape and size of a desired molded article, and other factors.
[0153] The molding temperature is usually not lower than the melting point of the polyolefin in the polyolefin composition of the present invention but lower than the lower temperature selected from the decomposition temperatures of the perfluoroelastomer and the polyolefin, and is within the range of 100° C. to 350° C.
[0154] In the case of extrusion molding, the molding temperature is also referred to as the extrusion temperature.
[0155] The polyolefin composition of the present invention enables disappearance of melt fracture occurred at the start of molding in a short time even when extrusion-molded at a high extrusion rate. Further, adding only a small amount of the processing aid that is a perfluoroelastomer to a specific polyolefin enables disappearance of melt fracture in an equal period of time in comparison with conventional techniques. Thus, the polyolefin composition can be molded at a high temperature and at a high molding rate. For example, the molding can be performed at a molding temperature of 280° C. or higher, and can be performed at a shear rate of 800 to 2500 sec −1 .
[0156] As mentioned above, a method of producing a molded article including a step of providing a polyolefin composition by mixing the perfluoroelastomer and the polyolefin and a step of providing a molded article by molding the polyolefin composition at 220° C. or higher is also one aspect of the present invention. Production of a molded article by such a production method including high-temperature molding enables a decrease in melt viscosity of the polyolefin that is a melt-fabricable polymer, likely improving the molding processability and the appearance of the molded article.
[0157] Further, molding the polyolefin composition at a shear rate of 800 to 2500 sec −1 in the step of providing a molded article is also one preferred embodiment of the present invention. Since such a production method includes molding at a high rate, the method is expected to improve the productivity.
[0158] In the step of providing a polyolefin composition in the production method, the composition is preferably obtained by mixing the perfluoroelastomer and the polyolefin in a wt % ratio of 0.0001 to 1 wt %.
[0159] The molded article of the present invention may have any of various shapes, such as a sheet shape, a film shape, a rod shape, a pipe shape, or fibrous shape.
[0160] The molded article may be used in any application in accordance with the type of the polyolefin used. For example, the molded article can be suitably used in applications strongly requiring mainly physical properties, such as mechanical properties, and surface properties.
[0161] Examples of uses of the molded article include films, bags, coating materials, tablewares such as containers for beverages, electric wires, cables, pipes, fibers, bottles, gasoline tanks, and other molded articles in various industries.
Advantageous Effects of Invention
[0162] The composition including the processing aid for polyolefins of the present invention has the aforementioned configuration. Thus, the composition enables disappearance of melt fracture occurred at the start of molding in a short time even when a polyolefin that is a melt-fabricable polymer is extrusion-molded at a high extruding rate.
BRIEF DESCRIPTION OF DRAWINGS
[0163] FIG. 1 is a chart of die pressure changes over time in extrusion processes of Example 1 and Comparative Examples 2 and 5.
[0164] FIG. 2 is a chart of die pressure changes over time in extrusion processes of Examples 10 to 13 and Comparative Examples 6 to 8.
[0165] FIG. 3 is a chart of die pressure changes over time in extrusion processes of Examples 14 to 16 and Comparative Examples 9 to 11.
[0166] FIG. 4 is a chart of die pressure changes over time in extrusion processes of Examples 14 and 17 to 20 and Comparative Examples 9 to 12.
[0167] FIG. 5 is a chart of die pressure changes over time in extrusion processes of Examples 21 to 23 and Comparative Example 13.
[0168] FIG. 6 is a chart of die pressure changes over time in extrusion processes of Examples 24 to 26 and Comparative Example 14.
[0169] FIG. 7 is a chart of die pressure changes over time in extrusion processes of Examples 27 to 29 and Comparative Example 15.
DESCRIPTION OF EMBODIMENTS
[0170] The present invention will be more specifically described referring to examples and comparative examples. Still, the invention is not limited to these examples.
[0171] The measured values described in the following examples and comparative examples are values determined by the following methods.
1. Composition of Copolymer
[0172] The composition of the copolymer was determined using a 19 F-NMR device (AC300P, Bruker Corp.).
2. Melt Flow Rate (MFR)
[0173] The melt flow rate was determined in conformity with ASTM D3159.
[0174] MFR measurement for PVDF: 240° C., 49 N
[0175] MFR measurement for TFE/HFP/VdF: 265° C., 49 N
3. Mooney Viscosity (ML 1+20 )
[0176] The Mooney viscosity (ML 1+20 ) was determined at 170° C. in conformity with JIS K6300-1.
4. Melting Point (mp)
[0177] The temperature corresponding to the maximum value on a melting heat curve obtained using a DSC device (Seiko Instruments Inc.) at a temperature increasing rate of 10° C./min was defined as the melting point.
5. Melt Fracture Disappearance Time
[0178] A polyolefin alone was extruded until the pressure was stabilized with melt fracture occurred on the entire surface. At the time when the screw of the extruder became visible, the materials such as a processing aid of each composition were put into a hopper. This timing was defined as 0. Then, the period of time from 0 to the time when the melt fracture disappeared and the entire surface of the molded article became smooth was defined as the melt fracture disappearance time. The disappearance of the melt fracture was confirmed by visual observation and touch examination.
[0179] If the visual observation and touch examination confirm that the entire surface does not have a gloss, smooth surface with no melt fracture but have a stripe-like, entirely or partially undulated surface, this state is called “shark skin” herein.
6. Pressure Decrease and Pressure Stabilization Time
[0180] In the extrusion evaluation to be mentioned later, the extrusion starts with an initial extrusion pressure (initial pressure) observed when linear low-density polyethylene alone is used without addition of a processing aid. The pressure is then decreased as a processing aid is added and the effect thereof is exerted, and finally the pressure is stabilized at substantially a constant pressure (stabilized pressure). The difference between the initial pressure and the stabilized pressure was defined as the pressure decrease. The period of time until the pressure reaches the stabilized pressure was defined as the pressure stabilization time.
<Preparation of Processing Aid>
[0181] The fluoropolymers PFEL 1 to PFEL 9 used in Examples 1 to 24 were produced with the compositions shown in Table 1 by substantially the same method as the polymerization disclosed in the examples of WO 01/023470 and WO 99/50319. In the examples, these fluoropolymers produced were each mixed with a anti re-agglomerating agent in a weight ratio (fluoropolymer/anti re-agglomerating agent) of 90/10. The resulting mixtures were used as processing aids.
[0182] The anti re-agglomerating agent used was a mixture of talc, silica, and calcium carbonate prepared in advance.
[0183] The fluoropolymer PFEL 4+PEG used in Example 25 and the fluoropolymer PFEL 7+PEG used in Example 26 were each prepared by mixing the corresponding fluoropolymer produced and polyethylene glycol (number average molecular weight: 8675) in a weight ratio (fluoropolymer/polyethylene glycol) of 1/1. The resulting mixtures were used as processing aids.
[0184] The fluoropolymer FKM (fluororubber) used in Comparative Examples 2, 6, and 9 was produced with the composition shown in Table 2 by substantially the same method as the polymerization disclosed in the examples of JP 5140902 B. In Comparative Examples 2, 6, and 9, this fluoropolymer produced was mixed with a anti re-agglomerating agent in a weight ratio (fluoropolymer/anti re-agglomerating agent) of 90/10. The resulting mixture was used as a processing aid. The anti re-agglomerating agent was the same as in Example 1.
[0185] The FKM+PEG used in Comparative Examples 3, 7, and was prepared by mixing the fluoropolymer FKM (fluororubber) used in Comparative Examples 2, 6, and 9 with PEG in a weight ratio (FKM/PEG) of 1/2. The resulting mixture was used as a processing aid. PEG was the same as in Example 25.
[0186] The fluoropolymer PVDF used in Comparative Example 4 was NEOFLON VDF VP-825 (Daikin Industries, Ltd.).
[0187] The fluoropolymer (tetrafluoroethylene (TFE)/hexafluoropropylene (HFP)/vinylidene fluoride (VDF) copolymer) used in Comparative Examples 5, 8, and 11 to 15 was produced with the composition shown in Table 2 by substantially the same method as disclosed in the examples of JP 4834971 B and U.S. Pat. No. 6,277,919 B1. In Comparative Examples 5, 8, and 11 to 15, this fluoropolymer was used as a processing aid.
(Production of Masterbatch)
[0188] The processing aid was mixed with linear low-density polyethylene (LLDPE 1002YB, ExxonMobil Corp.) such that the amount of the processing aid was 5 wt % based on the sum of the weights of the linear low-density polyethylene and the processing aid, and then 0.1 wt % of an antioxidant was mixed therewith. The mixture was put into a twin-screw extruder (Labo Plastomill 30C150, screw L/D: 25, Toyo Seiki Seisakusho, Ltd.) and was processed at a screw rotational speed of 80 rpm. Thereby, pellets containing the processing aid were obtained. The obtained pellets containing the processing aid were mixed using a tumbler mixer. The mixture was processed at a screw rotational speed of 100 rpm so as to improve the dispersion homogeneity of the processing aid in the resulting masterbatch while the other conditions were the same as for providing the pellets. Thereby, a processing aid-containing masterbatch containing the processing and the polyolefin was obtained.
[0189] The temperature conditions in extrusion were as follows.
[0190] Cylinder temperature: 150° C., 170° C., and 180° C.
[0191] Die temperature: 180° C.
[0192] An ultrathin slice was cut out of the resulting pellet and was microscopically observed using a reflected light microscope. The resulting image was binarized using an optical analyzer. This confirmed that the processing aid in the form of fine particles was dispersed in the linear low-density polyethylene in the resulting pellets.
[0193] The average dispersed particle size in the resulting pellets, determined on the binarized image, was 5 μm or smaller.
Extrusion Evaluation 1
Examples 1 to 9
[0194] The masterbatch containing the processing aid (one of PFELs 1 to 9+anti re-agglomerating agent) molded using the above twin-screw extruder was added to and tumble-mixed with linear low-density polyethylene (LLDPE 1201XV, ExxonMobil Corp.) such that the amount of the masterbatch was 1 wt % based on the sum of the weights of the linear low-density polyethylene and the masterbatch. The mixture was extruded using a single screw extruder (Rheomex OS, HAAKE, L/D: 33, screw diameter: 20 mm) at a cylinder temperature of 180° C. to 200° C., a die temperature of 200° C., and a screw rotational speed of 30 rpm. The die pressure change was observed for 60 minutes. Then, the screw rotational speed was successively changed to 10 rpm, 80 rpm, and 5 rpm, and the die pressure change was observed respectively for 10 minutes, 15 minutes, and 120 minutes.
Comparative Example 1
[0195] The extrusion evaluation was performed in the same manner as in Examples 1 to 9 except that the linear low-density polyethylene (LLDPE 1201XV, ExxonMobil Corp.) alone was extruded using a single screw extruder.
Comparative Examples 2 to 5
[0196] The extrusion evaluation was performed in the same manner as in Comparative Example 1 except that the masterbatch containing the processing aid (disclosed in Table 3) molded using the twin-screw extruder was added to and tumble-mixed with the linear low-density polyethylene (LLDPE 1201XV, ExxonMobil Corp.) such that the amount of the masterbatch was 1 wt % based on the sum of the weights of the linear low-density polyethylene and the masterbatch.
[0197] Tables 1 and 2 show the compositions of the fluoropolymers used in the examples and the comparative examples. Table 3 shows the results of the extrusion evaluations in Examples 1 to 9 and Comparative Examples 1 to 5. FIG. 1 shows the die pressure changes over time in the extrusion processes of Example 1 and Comparative Examples 2 and 5.
[0000]
TABLE 1
Composition of
fluoropolymer
ML 1+20
(mol %)
Fluoropolymer
(170° C.)
TFE
PMVE
CNVE
PFEL 1
83
57.6
42.4
0
PFEL 2
22
58.4
41.6
0
PFEL 3
48
58.7
41.3
0
PFEL 4
65
56.9
43.1
0
PFEL 5
98
59.5
40.5
0
PFEL 6
78
56.8
42.6
0.6
PFEL 7
80
68.6
30.9
0.5
PFEL 8
114
67.2
31.3
1.1
PFEL 9
unmeasurable
77.6
21.9
0.5
[0000]
TABLE 2
Composition of
mp
MFR
fluoropolymer (mol %)
Fluoropolymer
(° C.)
(g/10 min)
TFE
Ethylene
VDF
HFP
FKM
—
—
0
0
78
22
TFE/HFP/VDF
119
8.5
39
0
51
11
* MFR measurement for PVDF: 230° C., 49N
* MFR measurement for TFE/HFP/VDF: 265° C., 49N
[0000]
TABLE 3
Die pressure (MPa)
Processing aid
30 rpm
10 rpm
80 rpm
5 rpm
Example 1
PFEL 1 + SI
19.8
10.6
34.1
7.3
Example 2
PFEL 2 + SI
23.5
12.7
33.8
9.0
Example 3
PFEL 3 + SI
23.9
11.0
34.2
10.1
Example 4
PFEL 4 + SI
20.6
10.4
34.4
7.9
Example 5
PFEL 5 + SI
22.4
11.4
33.6
7.0
Example 6
PFEL 6 + SI
20.8
10.0
33.3
12.5
Example 7
PFEL 7 + SI
19.1
10.6
32.5
12.4
Example 8
PFEL 8 + SI
22.6
12.8
34.6
12.6
Example 9
PFEL 9 + SI
21.3
13.5
32.5
12.5
Comparative
Not added
31.5
19.1
37.9
12.7
Example 1
Comparative
FKM + SI
26.0
14.0
38.5
11.2
Example 2
Comparative
FKM + PEG
26.7
16.0
38.4
11.9
Example 3
Comparative
PVDF
24.3
11.6
37.2
7.6
Example 4
Comparative
TFE/HFP/VDF
24.3
12.1
35.6
9.4
Example 5
[0198] The abbreviations in the tables represent the following.
[0199] TFE: tetrafluoroethylene
[0200] PMVE: CF 2 ═CFOCF 3
[0201] CNVE: CF 2 ═CFOCF 2 CF(CF 3 )OCF 2 CF 2 CN
[0202] VDF: vinylidene fluoride
[0203] HFP: hexafluoropropylene
[0204] SI: anti re-agglomerating agent
[0205] Table 3 shows that use of the processing aid of the present invention led to a greater pressure decrease at 30 rpm and 80 rpm than in Comparative Examples 2 to 5.
[0206] Table 4 shows the shear rates calculated by the following formula.
[0000]
Y
=
4
Q
π
R
3
[
Math
.
1
]
[0207] The abbreviations in the formula represent the following.
[0208] γ: shear rate (sec −1 )
[0209] Q: amount of matter extruded (kg/hr)
[0210] R: diameter of die (mm)
[0000]
TABLE 4
Screw rotational speed
rpm
30
10
80
5
Shear rate
sec −1
445
129
1187
59
Extrusion Evaluation 2
Example 10
[0211] The masterbatch containing the processing aid used in Example 1 was added to and tumble-mixed with linear low-density polyethylene (LLDPE 1201XV, ExxonMobil Corp.) such that the amount of the masterbatch was 1 wt % based on the sum of the weights of the linear low-density polyethylene and the masterbatch. The resulting masterbatch-containing linear low-density polyethylene was extruded using a single screw extruder (Rheomex OS, HAAKE, L/D: 33, screw diameter: 20 mm) at a cylinder temperature of 170° C. to 200° C., a die temperature of 200° C., and a screw rotational speed of 80 rpm. The die pressure change and the melt fracture change were observed.
Examples 11 to 13
[0212] The extrusion evaluation was performed in the same manner as in Example 10 except that the processing aid-containing masterbatch used in Example 1 was added such that the amount thereof was 0.05, 0.02, or 0.01 wt % based on the sum of the weights of the linear low-density polyethylene and the masterbatch.
Comparative Examples 6, 7, and 8
[0213] The extrusion evaluation was performed in the same manner as in Example 10 except that the processing aid-containing masterbatch used in Comparative Examples 2, 3, or 5 was used.
[0214] Table 5 shows the evaluation results and other data in Examples 10 to 13 and Comparative Examples 6 to 8. FIG. 2 shows the die pressure changes over time in the extrusion processes of Examples 10 to 13 and Comparative Examples 6 to 8.
[0000]
TABLE 5
Concentration of
Amount (ΔP) of
Melt fracture
processing aid added
pressure decrease
disappearance time
Appearance of
Processing aid
(ppm)
(MPa)
(min)
extrudate after test
Example 10
PFEL 1 + SI
500
3.1
10
Glossy
Example 11
PFEL 1 + SI
25
3.1
20
Glossy
Example 12
PFEL 1 + SI
10
2.3
30
Glossy
Example 13
PFEL 1 + SI
5
1.8
40
Glossy
Comparative
FKM + SI
500
Note 1)
70 or longer
Shark skin
Example 6
Comparative
FKM + PEG
500
Note 2)
70 or longer
Shark skin
Example 7
Comparative
TFE/HFP/VDF
500
1.6
70 or longer
Shark skin
Example 8
Note 1) Extrusion pressure increased by 0.5 MPa
Note 2) Failed to achieve stable extrusion
[0215] In Table 5, the concentration (ppm) of the processing aid added means the proportion of the processing aid based on the sum of the weights of the linear low-density polyethylene and the masterbatch.
[0216] Table 5 and FIG. 2 show the following. In Example 10, the pressure decreased by 3.1 MPa within 10 minutes from the start of adding the masterbatch, and the melt fracture completely disappeared. In Examples 11 to 13, the amount of pressure decreased was reduced as the concentration of the processing aid added decreased. Still, the melt fracture completely disappeared within 70 minutes from the addition even when the concentration of the processing aid added was 5 ppm. In contrast, in Comparative Example 6, the extrusion pressure conversely increased by 0.5 MPa. Comparative Example 7 failed to provide stable extrusion. In Comparative Example 8, the pressure decreased by 1.6 MPa. In Comparative Examples 6 to 8, the melt fracture did not disappear even after 70 minutes from the start of adding the masterbatch.
Extrusion Evaluation 3
Examples 14, 15, and 16
[0217] The extrusion evaluation was performed in the same manner as in Extrusion evaluation 2 except that the processing aid-containing masterbatch used in Example 1, 4, or 5 was used, the cylinder temperature was set to 210° C. to 240° C., and the die temperature was set to 240° C. The shear rate calculated from the formula of Math. 1 was about 1,200 sec −1 .
Comparative Examples 9, 10, 11
[0218] The extrusion evaluation was performed in the same manner as in one of Examples 14 to 16 except that the processing aid-containing masterbatch used in Comparative Example 2, 3, or 5 was used.
[0219] Table 6 shows the evaluation results and other data in Examples 14 to 16 and Comparative Examples 9 to 11. FIG. 3 shows the die pressure changes over time in the extrusion processes of Examples 14 to 16 and Comparative Examples 9 to 11.
[0000]
TABLE 6
Concentration of
Amount (ΔP) of
Melt fracture
processing aid added
pressure decrease
disappearance time
Appearance of
Processing aid
(ppm)
(MPa)
(min)
extrudate after test
Example 14
PFEL 1 + SI
500
9.5
10
Glossy
Example 15
PFEL 4 + SI
500
8.1
10
Glossy
Example 16
PFEL 5 + SI
500
7.4
10
Glossy
Comparative
FKM + SI
500
4.6
70 or longer
Shark skin
Example 9
Comparative
FKM + PEG
500
4.3
70 or longer
Shark skin
Example 10
Comparative
TFE/HFP/VDF
500
5.6
20
Glossy
Example 11
[0220] Table 6 and FIG. 3 show the following. In Examples 14 to 16, the melt fracture completely disappeared within 10 minutes from the start of adding the masterbatch. In contrast, in Comparative Examples 9 and 10, the pressure decrease (amount ΔP of pressure decreased) was smaller than in Examples 14 to 16, and the melt fracture did not completely disappear even after 70 minutes from the start of adding the masterbatch. In Comparative Example 11, the pressure decrease (amount ΔP of pressure decreased) was smaller than in Examples 14 to 16, and the period of time until the melt fracture completely disappeared was longer than in Examples 14 to 16.
Examples 17 to 20
[0221] The extrusion evaluation was performed in the same manner as in Example 15 except that the processing aid-containing masterbatch used in Example 14 was added such that the amount thereof was 0.2, 0.1, 0.05, or 0.02 wt % based on the sum of the weights of the linear low-density polyethylene and the masterbatch.
Comparative Example 12
[0222] The extrusion evaluation was performed in the same manner as in Comparative Example 11 except that the processing aid-containing masterbatch used in Comparative Example 11 was added such that the amount thereof was 0.2 wt % based on the sum of the weights of the linear low-density polyethylene and the masterbatch.
[0223] Table 7 shows the evaluation results and other data in Examples 14 and 17 to 20 and Comparative Examples 9 to 12. FIG. 4 shows the die pressure changes over time in the extrusion processes of Examples 14 and 17 to 20 and Comparative Examples 9 to 12.
[0000]
TABLE 7
Concentration of
Amount (ΔP) of
Melt fracture
processing aid added
pressure decrease
disappearance time
Appearance of
Processing aid
(ppm)
(MPa)
(min)
extrudate after test
Example 14
PFEL 1 + SI
500
9.5
10
Glossy
Example 17
PFEL 1 + SI
100
6.8
10
Glossy
Example 18
PFEL 1 + SI
50
5.5
10
Glossy
Example 19
PFEL 1 + SI
25
3.6
20
Glossy
Example 20
PFEL 1 + SI
10
1.2
40
Glossy
Comparative
FKM + SI
500
4.6
70 or longer
Shark skin
Example 9
Comparative
FKM + PEG
500
4.3
70 or longer
Shark skin
Example 10
Comparative
TFE/HFP/VDF
500
5.6
20
Glossy
Example 11
Comparative
TFE/HFP/VDF
100
3.6
70 or longer
Shark skin
Example 12
[0224] Table 7 and FIG. 4 show the following. In Examples 14 and 17 to 20, the melt fracture disappearance time became longer as the concentration of the processing aid added decreased. Still, the melt fracture completely disappeared within 10 to 40 minutes. In contrast, in Comparative Examples 9, 10, and 12, the pressure decrease was observed, but the melt fracture did not completely disappear even after 70 minutes from the start of adding the masterbatch. In Comparative Example 11, the pressure decrease was observed and the melt fracture completely disappeared, but the melt fracture disappearance time was longer than in Example 14 in which the same concentration of the processing aid was added.
Extrusion Evaluation 4
Example 21
[0225] The extrusion evaluation was performed in the same manner as in Extrusion evaluation 2 except that the processing aid-containing masterbatch used in Example 4 was used, the cylinder temperature was set to 250° C. to 280° C., and the die temperature was set to 280° C. The shear rate calculated from the formula of Math. 1 was about 1,190 sec −1 .
Examples 22 and 23
[0226] The extrusion evaluation was performed in the same manner as in Example 21 except that the processing aid-containing masterbatch used in Example 21 was added such that the amount thereof was 0.2 or 0.1 wt % based on the sum of the weights of the linear low-density polyethylene and the masterbatch.
Comparative Example 13
[0227] The extrusion evaluation was performed in the same manner as in Example 21 except that the processing aid-containing masterbatch used in Comparative Example 5 was used.
[0228] Table 8 shows the evaluation results and other data in Examples 21 to 23 and Comparative Example 13. FIG. 5 shows the die pressure changes over time in the extrusion processes of Examples 21 to 23 and Comparative Example 13.
[0000]
TABLE 8
Concentration of
Amount (ΔP) of
Melt fracture
processing aid added
pressure decrease
disappearance time
Appearance of
Processing aid
(ppm)
(MPa)
(min)
extrudate after test
Example 21
PFEL 4 + SI
500
8.3
10
Glossy
Example 22
PFEL 4 + SI
100
5.9
10
Glossy
Example 23
PFEL 4 + SI
50
4.5
10
Glossy
Comparative
TFE/HFP/VDF
500
5.4
40
Glossy
Example 13
[0229] Table 8 and FIG. 5 show the following. In Examples 21 to 23, the melt fracture completely disappeared within 10 minutes from the start of adding the masterbatch. In Comparative Example 13, the amount of pressure decreased is smaller and the period of time from the start of adding the masterbatch to the disappearance of the melt fracture was longer than in Example 21 in which the same concentration of the processing aid was added.
Extrusion Evaluation 5
Evaluation 1 with Ultra-High Shear Rate
Examples 24 to 26
[0230] The masterbatch containing PFEL 7+anti re-agglomerating agent, PFEL 4+PEG, or PFEL 7+PEG as the processing aid was added to and tumble-mixed with linear low-density polyethylene (LLDPE 1201XV, ExxonMobil Corp.) such that the amount of the masterbatch was 1 wt % based on the sum of the weights of the linear low-density polyethylene and the masterbatch. The resulting masterbatch-containing linear low-density polyethylene was extruded using a single screw extruder (Rheomex OS, HAAKE, L/D: 33, screw diameter: 20 mm) at a cylinder temperature of 190° C. to 220° C., a die temperature of 220° C., and a screw rotational speed of 70 rpm. The die pressure change and the melt fracture change were observed. The shear rate calculated by the formula of Math. 1 was about 2,500 sec −1 .
Comparative Example 14
[0231] The extrusion evaluation was performed in the same manner as in Example 24 except that the processing aid-containing masterbatch used in Comparative Example 5 was used.
[0232] Table 9 shows the evaluation results and other data in Examples 24 to 26 and Comparative Example 14. FIG. 6 shows the die pressure changes over time in the extrusion processes of Examples 24 to 26 and Comparative Example 14.
[0000]
TABLE 9
Concentration of
Amount (ΔP) of
Melt fracture
processing aid added
pressure decrease
disappearance time
Appearance of
Processing aid
(ppm)
(MPa)
(min)
extrudate after test
Example 24
PFEL 7 + SI
500
1.7
10
Glossy
Example 25
PFEL 4 + PEG
500
1.9
10
Glossy
Example 26
PFEL 7 + PEG
500
2.1
20
Glossy
Comparative
TFE/HFP/VDF
500
1.4
70 or longer
Shark skin
Example 14
[0233] Table 9 and FIG. 6 show the following. In Examples 24 to 26, the melt fracture completely disappeared within 70 minutes from the start of adding the masterbatch. In Comparative Example 14, the amount of pressure decreased was smaller than in Example 24 in which the same concentration of the processing aid was added, and the melt fracture did not completely disappear even after 70 minutes from the start of adding the masterbatch.
Extrusion Evaluation 6
Evaluation 2 with Ultra-High Shear Rate
Examples 27 to 29
[0234] The processing aid-containing masterbatch used in Example 4 was added to and tumble-mixed with linear low-density polyethylene (LLDPE 1201XV, ExxonMobil Corp.) such that the amount of the masterbatch was 1, 0.1, or 0.05 wt % based on the sum of the weights of the linear low-density polyethylene and the masterbatch. The resulting masterbatch-containing linear low-density polyethylene was extruded using a single screw extruder (Rheomex OS, HAAKE, L/D: 33, screw diameter: 20 mm) at a cylinder temperature of 210° C. to 240° C., a die temperature of 240° C., and a screw rotational speed of 70 rpm. The die pressure change and the melt fracture change were observed. The shear rate calculated by the formula of Math. 1 was about 2,400 sec −1 .
Comparative Example 15
[0235] The extrusion evaluation was performed in the same manner as in Example 27 except that the processing aid-containing masterbatch used in Comparative Example 5 was used.
[0236] Table 10 shows the evaluation results and other data in Examples 27 to 29 and Comparative Example 15. FIG. 7 shows the die pressure changes over time in the extrusion processes of Examples 27 to 29 and Comparative Example 15.
[0000]
TABLE 10
Concentration of
Amount (ΔP) of
Melt fracture
processing aid added
pressure decrease
disappearance time
Appearance of
Processing aid
(ppm)
(MPa)
(min)
extrudate after test
Example 27
PFEL 4 + SI
500
6.0
10
Glossy
Example 28
PFEL 4 + SI
50
2.9
10
Glossy
Example 29
PFEL 4 + SI
25
2.6
10
Glossy
Comparative
TFE/HFP/VDF
500
2.3
70 or longer
Shark skin
Example 15
[0237] Table 10 and FIG. 7 show the following. In Examples 27 to 29, the melt fracture completely disappeared within 70 minutes from the start of adding the masterbatch. In Comparative Example 15, the amount of pressure decreased was smaller than in Example 27 in which the same concentration of the processing aid was added, and the melt fracture did not completely disappear even after 70 minutes from the start of adding the masterbatch.
INDUSTRIAL APPLICABILITY
[0238] Since the processing aid for polyolefins and the polyolefin composition of the present invention have the aforementioned configurations, they can be used in a wide variety of fields for films, bags, coating materials, tablewares such as containers for beverages, electric wires, cables, pipes, fibers, bottles, gasoline tanks, and other molded articles in various industries. | The present invention aims to provide a polyolefin composition including: a processing aid for polyolefins that enables disappearance of melt fracture occurred at the start of molding in a short time even when a polyolefin that is a melt-fabricable polymer is extrusion-molded at a high rate; and a specific polyolefin. The present invention relates to a processing aid for polyolefins, including a perfluoroelastomer. The processing aid is intended to be used for extrusion-molding at least one polyolefin selected from the group consisting of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, metallocene linear low-density polyethylene, polypropylene, and polyvinyl chloride. | 2 |
BACKGROUND OF THE INVENTION
Animal pelts have long been stretched on circular wooden frames to which the pelts were secured by sewing. They have also conventionally been stretched on plywood boards to which the pelts were attached by nailing. Both methods require a time consuming operation of attaching the pelt to the support, and any peripheral adjustment after mounting has begun is also time consuming. The board method has the further disadvantage of exposing only one side of the pelt.
SUMMARY OF THE INVENTION
The present invention provides an improved system of stretching a pelt, using a peripherally adjustable ring of spring material, a clamp to lock the ring after it has been adjusted, and hooks securing the pelt to the ring. The ring is preferably of resilient steel wire extending to a circle plus a substantial overlap when in a relaxed condition.
BRIEF DESCRIPTION OF THE DRAWING
The accompanying drawing schematically illustrates a present preferred embodiment of the pelt stretcher of the invention, in which:
FIG. 1 is a plan view of a pelt mounted in the stretcher of the invention;
FIG. 2 is an enlarged and partially broken away detail view of the attachment of one end of the wire frame shown in FIG. 1 to an overlapping portion of the wire frame;
FIG. 3 is a section of the line III--III in FIG. 2;
FIG. 4 is an enlarged section taken on the line IV--IV in FIG. 1, showing the clamp holding the wire frame but omitting the pelt and hooks securing the pelt to the frame; and,
FIG. 5 is an enlarged section of the line V--V in FIG. 1, showing details of a hook holding the pelt on the wire frame.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now more particularly to the drawing, and initially to FIG. 1, there is shown an animal pelt 10 secured by a series of spaced hooks 12 to a circular frame 14.
The frame 14 is a circular length of elongated resilient material, preferable quarter-length diameter music wire. The end portions 16 and 18 of the frame 14 have a substantial overlap, and each of these ends is heated and bent to hook around the adjacent portion of the other end so as to be slidable therealong. For example, the overlapping wire end 16 has a hook portion 20 extending around the overlapping wire end 18, as shown in FIGS. 2 and 3. The wire ends 16 and 18 are thus readily slideable along each other to adjust the diameter and length of the periphery of the frame 14. When the desired diameter and periphery has been determined for a particular pelt to be mounted in the frame, a clamp 44 around the wire ends 16 and 18 is tightened to lock these wire ends together and thus lock the frame in its desired setting. As shown in FIG. 4, the clamp 22 is preferably of the so-called hose clamp type, consisting of a flexible metal band 24 which can be tightened around the wire end 16 and 18, and an adjustable screw 26 which engages a slot in the band 24 to operate in worm gear fashion to tighten or loosen the band 24.
The hooks 12 are preferably steel U-shaped hooks of the kind known as "shoat rings" and used in the noses of pigs to prevent them from rooting (as well as other known uses, such as securing automobile seat covers). As shown in FIG. 5, one end of the hook 12 is anchored around the frame 14, and the other end goes in the pelt 10.
As shown in FIGS. 1 and 5, each of the hooks 12 has a central portion and opposite end portions lying substantially in a common plane. The end portions of each hook 12 are convergent approaching their extremities, to achieve the desired hooking action.
The frame 14 is convenient to use, because a pelt can be placed in it and the frame can be adjusted to fit the pelt while the clamp 22 is enclamped. The clamp 22 is then tightened, and the hooks 12 can quickly be connected between the pelt and the frame 14 around its periphery. If it should turn out, part of the way through the operation, that some adjustment of the size of the frame 14 is needed, this can readily be accomplished by loosening the clamp 22, sliding the hooked ends of the overlapping wires 16 and 18 along each other, and then retightening the clamp 22 when the desired adjustment has been made.
While the frame of the invention could be used on various pelts, it is presently believed that its primary usefulness is for stretching beaver pelts.
While a present preferred embodiment and practice of the invention has been illustrated and described, it will be understood that the invention may be otherwise variously embodied and practiced within the scope of the following claims. | An animal pelt stretching frame of adjustable circular construction. Shoat ring hooks connect the pelt to a ring which has slidable end connections for adjustment and a clamp for locking. | 8 |
FIELD OF THE INVENTION
The present invention concerns electrophotographic photoreceptors. Particularly, it concerns a method for preparing an amorphous silicon based electrophotographic photoreceptors.
BACKGROUND OF THE INVENTION
Several recent developments have occurred in electrophotographic photoreceptor technology. New photoreceptors have a vapor deposited photosensitive layer consisting principally of amorphous silicon. This trend has developed because amorphous silicon photoreceptors have an increased life expectancy over conventional electrophotographic photoreceptors. The application of amorphous silicon to electrophotographic photoreceptors results in more electrically stable repeat characteristics, increased hardness, greater thermal stability, and a longer life expectancy.
In the past, a variety of amorphous silicon based electrophotographic photoreceptors have been proposed, for example, JP-A-54-78l35 and JP-A-54-8634l (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application").
Of these, a superior embodiment comprises an amorphous silicon based electrophotographic photoreceptor with functionally separated photosensitive layers. These layers include a charge generating layer wherein charge carriers are generated upon irradiation with light, and a charge transporting layer into which the charge carriers can be injected and transferred efficiently. The photosensitive layers include amorphous silicon films formed by glow-discharging a mixed gas comprising a gas of silane compounds such as silane or disilane, a gas containing carbon, oxygen or nitrogen, and a gas containing very small amounts of group III or group V elements. The amorphous silicon based electrophotographic photoreceptor just described was proposed in JP-A-62-9355.
In general, electrophotographic photoreceptors in which the charge transporting layer and the charge generating layer are functionally separated display charging properties which are affected by the characteristics of the charge transporting layer which comprises the largest portion of the photosensitive layer. The chargeability of an electrophotographic photoreceptor including a hydrogenated amorphous silicon film obtained by means of the glow discharge of the silane compounds mentioned above is about 30 V/μm or less. This figure is still inadequate. Further, the dark decay rate, which differs according to the conditions of use, in general, is very high, being at least some 20%/second. Consequently, electrophotographic photoreceptors which have an amorphous silicon based charge transporting layer of this type are limited to use in comparatively high speed systems. Otherwise, a specific development system is required since an adequate charge potential cannot be obtained. The thickness of the charge transporting layer can be increased in order to increase the charge potential, but this not only increases the time required to produce the film but also increases the probability of defects being produced while forming the film.
The prior art reference JP-A-63-6305l (corresponding to U.S. Pat. application Ser. No. 93,285) taught the use of an aluminum oxide film to function as the charge transporting layer.
However, when an aluminum oxide film is formed by methods such as ion plating or electron beam vapor deposition, cracks are generated on the film depending on various formation conditions, and transparency of the film deteriorates. Accordingly, when such a cracked aluminum oxide film is used as the charge transporting layer, the obtained electrophotographic photoreceptor displays unstable electric characteristics, and produces defective images.
The present invention was developed in view of problems of the conventional techniques such as those discussed above.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method for preparing an electrophotographic photoreceptor which has a novel charge transporting layer. That is, the method of the present invention shall prepare an electrophotographic photoreceptor which has a hard charge transporting layer, excellent transparency and extremely few or no cracks. Further, the photoreceptor will have excellent electrophotographic properties, including stabilized electric characteristics, and will produce fewer defective images.
Additional objects and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. The objects and advantages of the present invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The above object can be attained by a method for preparing an electrophotographic photoreceptor which comprises a substrate having thereon a charge generating layer containing an amorphous silicon as a main component, and a charge transporting layer containing aluminum oxide as a main component, wherein said charge transporting layer is formed by an ion plating method while introducing oxygen gas.
That is, to achieve the foregoing objects, and in accordance with the purposes of the present invention as embodied and broadly described herein, a method is provided for preparing an electrophotographic photoreceptor which comprises a first step of forming a charge generating layer containing amorphous silicon on a substrate. Next, a charge transporting layer containing aluminum oxide (Al 2 O 3 ) is formed by a ion plating method while introducing oxygen gas.
Another embodiment of the present invention includes a method for preparing an electrophotographic photoreceptor which comprises a first step of forming a charge transporting layer containing aluminum oxide (Al 2 O 3 ) on a substrate. Next, a charge generating layer containing amorphous silicon is formed.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to the present preferred embodiment of the present invention
Either an electrically conductive substrate or an insulating support can be used as the substrate element in the present invention. When an insulating substrate is used, it must be treated in such a way that at least the surface which is in contact with the other layers is rendered electrically conductive. Metals or alloys such as stainless steel or aluminum can be used as the electrically conductive substrate. Synthetic resin films or sheets of polyester, polyethylene, polycarbonate, polystyrene, polyamide; glass; ceramic; and paper can be used as the insulating substrate.
A charge generating layer of which amorphous silicon forms the principal component is formed on the upper side of the substrate. This layer can be formed using one of several known methods. For example, it may be formed using a glow discharge decomposition method, a sputtering method, an ion plating method, a vacuum vapor deposition method, or any other method known in the art. The film forming method can be selected according to the intended purpose. However, the preferred method is a plasma CVD method, in which silane or a silane based gas is decomposed in a glow discharge. If such a method is used, it is possible to form films containing a suitable amount of hydrogen in the film and having ideal characteristics such as a comparatively high dark resistance, a high photosensitivity, and containing a suitable amount of hydrogen in the film
An example of the plasma CVD method is described below.
Silanes, principally silane and disilane, or a gas obtained using silicon crystals, are used as the raw material gases in formation of a charge generating layer. A carrier gas such as hydrogen, helium, argon, and neon can also be used when forming the charge generating layer. Gases such as diborane (B 2 H 6 ) gas, and phosphine (PH 3 ) gas can be mixed with these raw material gases to include doped impurity elements such as boron or phosphorus in the film. Further, halogen atoms, carbon atoms, oxygen atoms, and nitrogen atoms can also be included in order to increase the dark resistance, increase the photosensitivity or increase the charging capacity. Moreover, elements such as germanium and tin may also be included in order to increase sensitivity of the photoreceptor in the long wavelength region.
The charge generating film generally has silicon for its principal component. The content of hydrogen is desirable in an atomic percentage range of 1 to 40%, with a range of 5 to 20% being preferable. The film thickness is established generally within a range from 0.1 to 30 μm, and preferably within a range from 0.2 to 5 μm.
When an alternating current discharge is being used, the film forming conditions are established appropriately as follows: frequency of from 50 Hz to 5 GHz, a reaction pressure within the reactor of from 1×10 -4 to 10 torr, a discharge power of from 10 to 2,000 W, and a substrate temperature of from 30° to 600° C. The thickness of the charge generating layer can be established as desired by adjusting the discharge period.
The charge transporting layer generally has oxides of aluminum forming the principal component. This layer is formed on the upper part or the lower part of the charge generating layer. This layer is transparent to visible light and has essentially no photosensitivity in the visible light region. It may, however, be photosensitive to ultraviolet light.
The charge transporting layer can only be formed using an ion plating method. Though aluminum or aluminum oxides can be used as the raw material, preferably aluminum oxide (Al 2 O 3 ) can be used. In practical terms, the raw material is placed in an oxygen free copper crucible which can be water cooled, located inside the vacuum chamber of the ion plating apparatus. The film forming conditions are as follows: vacuum inside the vacuum chamber 1×10 -5 to 1×10 -7 torr, voltage applied to the ionizing electrode +1 to +500 V, bias voltage applied to the substrate 0 to -2,000 V, electron gun voltage 0.5 to 50 kV, electron gun current 0.5 to 1,000 mA. Further, the substrate temperature is set at 20° to 1,000° C.
In the method of the present invention, oxygen gas is introduced directly and separately into the vacuum chamber. The amount of oxygen gas introduced can be controlled by means of the oxygen gas pressure inside the vacuum chamber. That is to say, after evacuating the inside of the vacuum chamber to the vacuum indicated above, oxygen gas is introduced in such an amount that the vacuum is generally within the range from 1×10 -6 to 1×10 2 torr, and preferably within the range from 1×10 -4 to 1×10 -1 torr. In this case, the transparency of the film decreases if the volume of oxygen gas introduced is small. However, the introduction of a higher volume of oxygen gas reduces the extent of crack formation in the resultant film. If too much oxygen gas is introduced, the film becomes excessively soft. Clearly, the amount of oxygen must be established within a suitable range.
Further, the thickness of the charge transporting film can be established appropriately by adjusting the ion plating time period. In the present invention, film thickness is generally set within the range from 2 to 100 μm, and preferably within the range from 3 to 30 μm.
Other layers may be formed, if desired, adjacent to the upper part or the lower part of either the charge generating layer or the charge transporting layer. Examples of such layers are described below. Layers, such as, p-Type semiconductor and n-type semiconductor layers, in which elements of group III or group V of the Periodic Table have been added to amorphous silicon, for example, or insulating layers such as layers of silicon nitride, silicon carbide, silicon oxide, and amorphous carbon, can be used as a charge injection preventing layers. Further, layers obtained by adding nitrogen, carbon, or oxygen to layers consisting of amorphous silicon can be used as adhesive layers. Moreover, layers which control the electrical and image forming characteristics of the Photoreceptor such as layers which contain elements of group IIIB and elements of group V of the Periodic Table at the same time, can also be used. The thickness of each of these layers can be set arbitrarily, but it is normally set within the range from 0.01 μm to 10 um.
Moreover, a surface protecting layer may be established to prevent degeneration of the surface of the photoreceptor by corona ions.
Each of the above-mentioned layers can be formed using the plasma CVD method. As described in connection with the charge generating layer, when impurity elements are added, a gaseous substance containing the impurity elements is introduced along with silane gas into the plasma CVD apparatus, and the mixture is subjected to glow discharge decomposition. Either an alternating current discharge or a direct current discharge can be used effectively for forming the films of each layer. When an alternating current discharge is used, the film forming conditions are as follows: the frequency normally ranges from 0.1 to 30 MHz and preferably 5 to 20 MHz, the vacuum during the discharge ranges generally from 1×10 -4 to 10 torr and preferably from 0.1 to 5 torr (13.3 to 66.7 Pa) and the substrate temperature ranges generally from 30° to 600° C., and preferably from 100° to 400° C.
EXAMPLE
The method of the present invention is further described by means of the following examples.
EXAMPLE 1
An a-Si:H film having a thickness of 1 μm was formed on an aluminum pipe of diameter 120 mm. That is to say, silane gas was introduced at a rate of 200 ml/min. into a capacitive coupled type plasma CVD apparatus. The pressure was set at 1.5 torr. The temperature of the substrate was set at 250° C. Glow discharge decomposition was carried out for 10 minutes with a 300 W, 13.56 MHz high frequency output.
The above-mentioned aluminum pipe was then introduced into the vacuum chamber of an ion plating apparatus. Next, 99.99% of alumina (Al 2 O 3 ) was introduced into the water cooled oxygen free copper crucible in the vacuum chamber, and the chamber was evacuated with a vacuum pump to a vacuum of 1×10 -6 torr, after which oxygen was introduced into the chamber until the pressure was 2×10 -4 torr. A voltage of 8.5 kV was applied to the electron gun with the power supply output set to provide a current of 240 mA. At this time, the ionizing electrode was set at 80 V and a bias voltage of -500 V was applied to the substrate itself. The electron beam output was adjusted in such a way that the deposition rate, according to a quartz oscillator film thickness monitor established in the vicinity of the aluminum pipe, was held constant at 34 Å/sec. A charge transporting layer consisting of an aluminum oxide film having a thickness of about 5 um was formed in this way with a film forming time of approximately 25 minutes.
The sample was then removed from the vacuum chamber. Investigation of the charge transporting layer confirmed that the aluminum oxide film which had been formed was transparent and that there were extremely few cracks in the film. Moreover, the film was a very hard film having a Vickers hardness (10 gram load) of 680.
EXAMPLE 2
An electrophotographic photoreceptor was made by the same way as in Example 1 except that oxygen gas was introduced to a pressure of 7×10 -4 torr. The charge transporting layer formed was transparent and had no cracks. The Vickers hardness (10 gram load) was 500.
COMPARATIVE EXAMPLE 1
An electrophotographic photoreceptor was made by the same way as in Example 1 except that no oxygen was introduced. The charge transporting layer formed was black in color and there were many cracks in the film. Furthermore, the Vickers hardness (10 gram load) was 200 and the film lacked strength.
EXAMPLE 3
An aluminum pipe having a diameter of about 120 mm was introduced into the vacuum chamber of an ion plating apparatus. Next, 99.9% alumina (Al 2 O 3 ) was introduced into the water cooled oxygen free copper crucible in the vacuum chamber. The chamber was evacuated with a vacuum pump to a vacuum of 2×10 -6 torr, after which oxygen was introduced into the chamber until the pressure was 2×10 -4 torr. A voltage of 8.5 kV was applied to the electron gun with the power supply output set to provide a current of 240 mA. At this time, the ionizing electrode was set at 70 V and a bias voltage of -400 V was applied to the substrate itself. The electron beam output was adjusted in such a way that the deposition rate, according to a quartz oscillator film thickness monitor established in the vicinity of the aluminum pipe was held constant at 31 Å/sec. A charge transporting layer consisting of an aluminum oxide film having a thickness of about 5 μm was formed in this way with a film forming time of approximately 25 minutes.
The layer was removed from the vacuum chamber. Investigation of the charge transporting layer confirmed that the aluminum oxide film which had been formed was transparent and that there were no cracks in the film. Moreover, the film was very hard film having a Vickers hardness (10 gram load) of 675.
Successively, an a-Si:H film having a thickness of 1 μm was formed on a charge transporting layer described above. That is, silane gas was introduced at a rate of 200 ml/min. into a capacitive coupled type plasma CVD apparatus and the pressure was set at 1.5 torr. The temperature of the substrate was wet at 250° C. Glow discharge decomposition was carried out for 10 minutes with a 300 W, 13.56 MHz high frequency output.
The thus-obtained electrophotographic photoreceptor had an excellent surface property, and an excellent electric characteristic. Further, it produced a copied image with no defects.
COMPARATIVE EXAMPLE 2
An electrophotographic photoreceptor was made by the same way as in Example 3 except that no oxygen was introduced. The charge transporting layer formed was black in color and there were many cracks in the film. Furthermore, the Vickers hardness (10 gram load) was180 and the film lacked strength.
The thus-obtained electrophotographic photoreceptor had a deteriorated surface property, unstable electric property, and several defects on a copied image.
Thus, it is possible, by means of the present invention, to manufacture electrophotographic photoreceptors which comprise novel charge transporting layers having excellent transparency, no cracks and a high hardness using aluminum or oxides thereof. Hence, the electrophotographic photoreceptors manufactured by means of the present invention have excellent durability, excellent electrophotographic characteristics and excellent image properties.
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. | A method for preparing an electrophotographic photoreceptor is disclosed, which comprises a substrate having thereon a charge generating layer containing an amorphous silicon as a main component and a charge transporting layer containing aluminum oxide as a main component, wherein the charge transporting layer is formed by an ion plating method while introducing oxygen gas. | 2 |
FIELD OF THE INVENTION
The present invention relates to a production of a monocrystalline layer (hereinafter referred to as a “monocrystalline material layer”) of a conducting or semiconducting material (hereinafter referred to as “material”) on a monocrystalline porous layer (hereinafter referred to as “porous material layer”) of the same material. If the material is silicon, for example, SOI (silicon on insulator) wafers can be produced starting with such a layer structure. These wafers can be advantageously used in semiconductor electronics and in silicon micromechanics.
BACKGROUND INFORMATION
In a conventional method of producing SOI wafers, two wafers of monocrystalline silicon having at least one oxidized surface are thermally bonded to one another with the silicon dioxide surfaces and then the one wafer is thinned back.
In the SIMOX (“separation by implanted oxygen”) method, oxygen ions are implanted in a monocrystalline silicon wafer, forming, after activation with silicon, a silicon dioxide layer which separates the wafer from a thin layer of silicon.
In another conventional method, silicon is deposited epitaxially on a porous monocrystalline silicon layer and then the porous silicon is oxidized.
In another conventional method, silicon is applied epitaxially to a porous, monocrystalline silicon layer, partially oxidized on its surface, after etching back.
All these conventional methods have in common the high manufacturing costs, caused by high consumption of materials or very expensive process steps, e.g., in the production of thick epitaxial layers.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a simple and inexpensive method of producing monocrystalline material layers on porous monocrystalline layers of the same material in a reproducible and time-saving manner.
This object is achieved with a method according to the present invention by applying a layer of amorphous material (hereinafter referred to as “amorphous material layer”) to the porous material layer and converting it to the monocrystalline material layer by a tempering procedure. Producing the monocrystalline material layer in two steps using the amorphous material layer is much less complicated and consumes much less energy than when the monocrystalline material layer is produced in one step, e.g., by epitaxy. The seeds supplied by the porous material layer, whose size is optionally (see below) reduced by oxide-masked surface areas, are sufficient to ensure complete conversion of the amorphous material to monocrystalline material. The porosity of the porous material layer is necessary in a subsequent step to permit their selective removal or selective conversion to the oxide form in the presence of the monocrystalline material layer plus optionally a wafer of the material.
It is advantageous to select the material from the group of aluminum, silicon, silicon carbide and gallium arsenide.
If the material is silicon, it is advantageously tempered at temperatures between about 600° C. and about 800° 0 C. Within this temperature range, a complete conversion of the amorphous silicon to monocrystalline silicon within approximately 15 to 24 hours is ensured.
It is advantageous to surface oxidize the porous material layer superficially before applying the amorphous material layer and to thin back the surface oxidized porous material layer to the extent that the porous material is exposed again in some areas. If the porous material layer is silicon, it is especially advantageous if it is surface oxidized dry or wet at about 400° C. to 800° C. Thinning back is advantageously performed by partially dissolving with a solvent for the oxide just formed, resputtering, regrinding, plasma etching or with HCl gas in a tempering tube. Growth of the oxide layer can be controlled with these methods, and in thinning back, essentially the oxidized porous material layer is removed in the direction of the layer normal so that the oxide is removed first from elevations projecting out of the plane of the layer, and then these elevations serve as seeds in conversion to monocrystalline material in the subsequent tempering. Therefore, the monocrystalline material layer formed in tempering is in contact with the porous material only at said elevations, but not in the pores. This facilitates the subsequent removal or conversion of the porous oxide, and the levelness of the surface of the monocrystalline material layer facing the porous material layer is improved without interfering with formation of the monocrystalline material layer.
It is advantageous if the amorphous material layer is applied by sputtering onto a target plate made of the material or by LPCVD or PECVD in an atmosphere containing at least one volatile compound of the material, for example, in SiH 4 or di- or trichlorosilane in applying silicon. These methods are not very complicated, can be controlled well and use the conventional equipment of semiconductor manufacture.
A structure according to the present invention can be advantageously used by bonding the monocrystalline material to a carrier substrate, and then the porous material layer is dissolved away, and the bond between the monocrystalline material layer and the substrate, normally a wafer of the same material, is dissolved. Because of its structure, the solubility of the porous material layer differs so greatly from that of the wafer and the monocrystalline material layer that the latter is practically not attacked when dissolving the porous material. Instead, the monocrystalline material layer retains its original thickness and the wafer can be reused. The monocrystalline material layer has excellent electrical and mechanical properties and can therefore be used for numerous applications, such as (if the material is semiconducting) the production of high-grade thin-film electronics.
The structure including the porous material layer, the monocrystalline material layer covering it and a wafer of the same material covered by it can be advantageously used to produce a structure which, like an SOI wafer, for example, includes the wafer, an insulation layer of mainly oxidized porous material applied to it and the monocrystalline material layer; this is accomplished by exposing the structure to oxidizing conditions for a specified period of time. In order for oxidation of the porous material to be complete, a great deal of time would be required, because the oxygen would have to diffuse from the side into the porous material layer, which has a very great diameter in relation to its thickness. To obtain a good insulator, it is not generally critical if needles of porous material completely surrounded by oxide are still present. This is true in particular when the structure is subjected to a reflow step after oxidation to compress the insulator. If oxidation of the porous material is to be complete, however, it is advantageous to provide the monocrystalline material layer with a pattern of through openings before oxidation, and it is especially advantageous to distribute the openings as uniformly as possible over the monocrystalline layer, there being enough tolerance so that it is not necessary to accept any problems in use of the SOI wafer, for example, because of the pattern. In oxidation of the porous material layer, the wafer and the monocrystalline material layer are not subject to any mentionable oxidative attack. If the insulator thus produced is made to collapse by reflow after oxidation, then the resulting structure not only has good insulating properties, but also has excellent mechanical and optical properties—assuming film stress is minimized. Film stress is minimal when the porous material has a porosity of approximately 50% to 60%.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 a shows a schematic cross-sectional diagram of a first stage of a method according to the present invention.
FIG. 1 b shows a schematic cross-sectional diagram of a second stage of the method according to the present invention.
FIG. 1 c shows a schematic cross-sectional diagram of a third stage of the method according to the present invention.
FIG. 2 a shows a schematic cross-sectional diagram of a first stage in further processing of the structure shown in FIG. 1 c.
FIG. 2 b shows a schematic cross-sectional diagram of a second stage in further processing of the structure shown in FIG. 1 c.
FIG. 3 shows a schematic cross-sectional diagram of a result of additional processing of the structure shown in FIG. 1 c.
DETAILED DESCRIPTION
The present invention is described below on the basis of an exemplary embodiment with the material being silicon. However, it should be understood that although the method according to the present invention has advantages when silicon is used and the structures thus produced can be advantageously used, the method according to the present invention and its embodiments are not limited to the use of silicon or to the process parameters such as temperatures indicated in the examples. Many modifications of these examples are possible within the scope of the present invention, and the structures produced from other materials can also be used advantageously within the scope of the present invention.
It should be noted that in the exemplary embodiment described below, silicon is always monocrystalline except in the amorphous silicon layer applied in a subsequent step. This property is therefore mentioned only when necessary for understanding the description.
FIG. 1 a shows a cross section through a structure with a silicon wafer 1 and a porous silicon layer 2 applied to the wafer. Layer 2 was produced by anodizing one surface of wafer 1 . This surface was exposed to a mixture containing hydrofluoric acid, water and ethanol, for example, while applying a voltage of a few volts, causing a current of less than approx. 30 mA/cm 2 to flow. Production of a porous silicon layer approximately 2 μm thick takes about one to three minutes. The structure of porous silicon layer 2 is such that the webs between the pores are about 2 nm to 10 nm wide, and the average pore diameter is also about 2 to 10 nm. The porous silicon layer is surface oxidized by subjecting it to dry or wet oxidation at temperatures between about 400 and 800° C., lasting between a few minutes and approximately half an hour, depending on the temperature used.
In the next step, the oxide is thinned back by immersing briefly in dilute hydrofluoric acid or dilute buffered hydrofluoric acid or by resputtering or regrinding to expose areas of the porous silicon structure. The areas which are monocrystalline have a long-range order. In principle, the surface oxidation and thinning back steps can be omitted if the layer of porous silicon is dissolved in the remaining course of the process.
An amorphous silicon layer 3 is deposited on porous silicon layer 2 by sputtering a target plate of silicon or by LPCVD or PECVD from an SiH 4 vapor phase, for example (see FIG. 1 b ). These deposition methods are commonly used in semiconductor technology.
By tempering at temperatures less than 800° C., preferably between approx. 400° and 800° C., amorphous silicon layer 3 is converted to a monocrystalline silicon layer 4 within about 20 to 30 minutes (see FIG. 1 c ), with the areas of porous silicon exposed by thinning back functioning as seeds. Structure 5 then obtained can be processed further to an SOI structure or to a layer of monocrystalline silicon applied to glass, metal, polymers, etc. into which high-grade thin-film electronics can be introduced.
To produce thin-film electronics on glass, for example (see FIG. 2 a ), structure 5 is anodically bonded or glued to a glass plate 6 with the exposed surface of the silicon layer, using a conventional adhesive, a photoresist or pitch, for example, as an adhesive. Then, porous silicon layer 2 is dissolved, thereby also separating layer 4 from wafer 1 . If layer 2 is exclusively silicon, ammonia or dilute potassium hydroxide solution can be a suitable solvent. If the porous silicon is oxidized at the surface, it is advantageous to first remove the oxide by immersing it briefly in dilute hydrofluoric acid and only then use the solvent for silicon. Next the thin-film electronic device is created in silicon layer 4 on glass plate 6 .
To produce the SOI structure, layer 4 is first structured in the desired manner with a pattern 7 of openings extending to the porous silicon, starting from structure 5 shown in FIG. 1 c , and then the porous silicon is thermally oxidized completely, as described above. As an alternative, the pattern may be omitted, and one may settle for incomplete oxidation instead, i.e., with an oxide that still contains needles of porous silicon. Finally, the structure is subjected to a heat treatment at a temperature between about 1100° C. and 1200° C. (reflow) the silicon dioxide thus produced being compressed, forming layer 8 . The structure then obtained is shown in FIG. 3 .
Another exemplary embodiment according to the present invention is described in greater detail below.
The method starts with a wafer of monocrystalline p-doped silicon. The wafer is clamped in an electrically insulating holder. The holder completely covered the back side of the wafer. A post electrode built into the holder contacted the back side of the wafer electrically, while the front side of the wafer is exposed. The holder is immersed in a 20% solution of hydrofluoric acid in a water-ethanol mixture. An electrode made of platinum, for example, is also immersed in the liquid. A voltage of 4.5 V is applied between the electrode and the post electrode (anode). A current with a density of 6.5 mA/cm 2 then flowed through the solution. Under these conditions, the silicon on the top side of the wafer is converted to porous silicon. An anodizing procedure is performed for ten minutes. A layer of porous silicon with an average thickness of about 1.2 μm is then produced. Electron microscopy reveals that the silicon webs between the pores had an average width of about 7 nm and the average pore diameter is on the order of about 5 nm. After the anodizing procedure, the wafer is removed from the holder, rinsed off, dried and then subjected to a wet thermal oxidation. Oxidation is performed at a temperature of 650° C. for 16 minutes. The exposed areas of the porous silicon are oxidized superficially. Then, the surface oxidized porous silicon layer is removed by sputtering to the extent that the porous silicon is exposed again in some areas, as confirmed by microscopic examination. A 1.5 μm thick amorphous silicon layer is applied to the thinned layer by sputtering at a pressure of 2.5·10 −4 bar, a voltage of 500 V and a power of 500 W, or in an inert atmosphere containing SiH 4 by standard LPCVD or by PECVD at 400° C., a pressure of 100·10 −3 bar and a power of 300 W within 30 to 60 minutes, depending on the method used. In a tempering step, the amorphous silicon is converted to a monocrystalline silicon layer at 540° C. within 24 hours.
To make the silicon layer available as an active layer on a glass substrate, the silicon layer is glued with its exposed surface to a glass plate. Pitch is used as the adhesive. Then, to remove the oxide, the wafer is immersed briefly in buffered hydrofluoric acid and next the porous silicon layer is dissolved with dilute KOH and thus the wafer is also separated from the silicon layer. The exposed surface of the silicon layer is of a very good quality, as shown by profile measurements. Four-point measurements showed that the layer has excellent electrical properties. In addition, its mechanical stability is very good. On the basis of these properties, the silicon layer is very well suited as the active layer for thin-film electronics.
The method described above is also generally applicable to other conducting and nonconducting materials, e.g., aluminum, silicon carbide and gallium arsenide, and should be adapted to the respective material accordingly. | To produce monocrystalline layers of conducting or semiconducting materials on porous monocrystalline layers of the same material in a reproducible and time-saving manner, a method is provided which involves applying an amorphous layer of the same material to the porous material and converting the amorphous layer to a monocrystalline layer by tempering. | 2 |
[0001] This application is a non-provisional application claiming the benefits of provisional application no. 61/516,758 filed Apr. 7, 2011.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] 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 Contract No. N68335-10-C-0508 awarded by the Naval Air Systems Command (NAVAIR) of the U.S. Department of Defense (DoD).
FIELD OF THE INVENTION
[0003] This invention relates to a vacuum chamber constructed with optical windows made to have a high resistance to helium leakage, and a fabrication and processing method thereof.
BACKGROUND OF THE INVENTION
[0004] The proposed applications that can benefit from cold and ultracold atom technology includes atom interferometry, quantum computing, nonlinear optics, atom interaction studies, atomic timekeeping, inertial navigation, magnetic sensing, and gravitational sensing. One serious obstacle to developing these applications has been the complexity and size of the vacuum systems required for ultracold atom production. Although recent scaled-down vacuum systems intended for producing Bose Einstein condensation (BEC) have begun to address this issue, there remains much that is still required in terms of miniaturization and reducing system complexity.
[0005] Active vacuum pumps like sputter-ion pumps and turbo pumps have become ubiquitous in cold and ultracold atom systems. In general, these pumps provide convenience, ease of use, and the ultra-high vacuum (UHV) conditions (10 −8 torr to 10 −13 torr) required for producing optically cooled and ultracold matter. A sputter ion pump works by ionizing vacuum impurities in the volume of the pump. A high voltage accelerates the ions toward the walls of the pump where they are sequestered via burial deep into the wall or by chemical reaction with the materials that form the wall. A turbo pump is a mechanical pump that uses spinning turbine blades to create a preferred direction of flow of vacuum impurities out of the volume of the chamber. There are several drawbacks to using these active vacuum pumps and these drawbacks become more significant under miniaturization for use in sensory applications based on optically cooled atoms.
[0006] Active pumps such as sputter ion pumps and mechanical turbo pumps have better pumping capability if they are large. Under miniaturization, the pumping capability of these active pumps is reduced to a point of diminishing returns. The large physical size of the active pump itself is a major limitation and dictates the ultimate size of the source. Furthermore, as cold atom vacuum chambers get smaller in size, the active pumps must be closer in proximity to the collections of cold and ultracold atoms. Stray magnetic fields from active vacuum pumps can have a detrimental effect on cold atom-based sensors. The effects of these stray fields are accentuated in smaller systems and it becomes increasingly difficult to shield the atoms from them. Elimination of such pumps can enable further miniaturization of ultracold atom sources and spur application development.
[0007] Traditional vacuum systems utilized in the production of optically cooled atoms and ultracold atoms (such as BEC) are large in size. It is common for these systems to weigh between 10 kg and 50 kg with length of about 1 meter in at least one physical dimension. These systems incorporate heavy suitcase-sized active pumps such as sputter ion pumps or mechanical turbo pumps to maintain the low pressures required for producing collections of cold and ultracold atoms. The required pressures can vary from as high as about 10 −8 torr to about 10 −13 torr depending on the goal of the apparatus. The chambers contain a mechanism to dispense the atoms of interest; typically alkali atoms such as rubidium or cesium. Atoms are dispensed into the chamber to form a low-density room-temperature vapor that can be cooled and confined in a magneto-optical trap (MOT). Traditional vacuum systems for producing ultracold matter can be based on a two-chamber design where the chambers are coupled using a narrow tube or aperture. A single-chamber design can also be used for optical cooling, however, the two-chamber design gives better vacuum performance albeit, at the cost of greater system size and complexity.
[0008] The present invention addresses the need for a miniature vacuum chamber with reduced reliance on active pumping to be used as a source for ultracold atoms. A UHV vacuum chamber is formed that eliminates or reduces the use of active vacuum pumps and further provides a simplified geometry for producing ultracold matter. The primary challenge in creating such a chamber is managing the permeation of substances, called vacuum impurities, into the vacuum chamber which add to the background pressure and spoil the necessary UHV conditions. Of particular concern is helium as a vacuum impurity. Helium is naturally found in the air and can readily diffuse through many window materials. Furthermore, helium is not effectively pumped by any passive getter material. The present invention provides a helium impervious window in a vacuum chamber used for atom cooling, trapping, and probing.
SUMMARY OF THE INVENTION
[0009] The present invention is a vacuum chamber for working with cold and ultracold atoms that can maintain ultra-high vacuum levels in a closed cavity with minimal or no active pumping. The chamber incorporates optical windows allowing atoms or molecules on the inside of the cavity to be addressed with light. One example of an application for which the vacuum chamber is well suited is the application of optically cooling atoms, ions, or molecules, but this invention is not limited to such applications and for one skilled in the art, it is easy to imagine other applications or fields for which this invention can be applied with minimal or no modification. The optical portions of the chamber are constructed from transparent materials having a helium permeability velocity below about 1×10 −13 cm 2 /s, the material made from ingredients preferably having an alumina content over about 4% by weight. The chamber may contain passive vacuum pumping in the form of an atom collector. Additionally, the chamber may contain a device for depositing atoms or molecules of specific species into the volume of the vacuum chamber which will be referred to in the text as a target atom injector.
[0010] A critical component of this invention is the method for processing the window material so that it has a reduced concentration of helium that is dissolved in the material.
[0011] The method of vacuum processing is a key part of this invention. The process of obtaining vacuum levels with sufficiently low pressures requires the vacuum chamber to be temporarily connected to a vacuum pumping apparatus or enclosed within a processing chamber that is connected to a pumping apparatus. The temperature of the chamber is elevated to between about 50 C and 450 C to liberate vacuum impurities. These vacuum impurities may contain surface impurities with high vapor pressures which are common on materials which have been exposed to normal atmosphere. They may also contain impurities trapped within the bulk of the glass and other materials that make up the vacuum chamber. Impurities include, but are not limited to, water vapor, hydrocarbons, nitrogen, hydrogen, oxygen, CO 2 , and noble gases(for example, helium). The temperature of the pumping apparatus or the temperature of a processing chamber connected to the pumping apparatus may also be elevated during the processing procedure to increase pumping speed and as a means of indirectly heating the chamber inside the processing chamber. During pumping and heating some of these impurities contained in the bulk material migrate to the surface where they can be pumped away by the pumping apparatus. The temperature of the chamber is raised to between about 50 C and 450 C to increase the rate of impurity migration out of the vacuum chamber materials. One example of an impurity that is critical to remove from the bulk of the vacuum chamber material is helium. Helium is found in the atmosphere at a partial pressure of about 4×10 −3 torr and because it is small and chemically non-reactive, it readily permeates through many materials. For materials used in a vacuum system with minimal or no active pumping, the dissolved helium impurity leads to serious vacuum contamination. Impurities are removed from all sides of the vacuum chamber materials by subjecting the exposed inner and outer surfaces to an environment (preferably a vacuum) that contains a low concentration of helium. One method is performed by enclosing the whole vacuum chamber within a vacuum processing enclosure. An alternate method can be performed by having a separate processing apparatuses for the inside of the vacuum chamber and one for the outside of the vacuum chamber. The method for removing helium from the bulk of the material is called degassing and is performed by baking the material or complete vacuum chamber in a helium free atmosphere. The mentioned atmosphere may be composed of a vacuum, or it may be a helium free purge gas. Low concentrations of helium will generally be achieved in the processing chamber by vacuum pumps that actively remove helium atoms from the volume of the processing chamber which represents the environment to which the surface of the vacuum chamber material is exposed during processing. The duration of vacuum processing of the vacuum chamber extends from between about 3×10 1 seconds to about 3×10 7 seconds. One alternative is to use a purge system incorporating a gas that has low helium partial pressure less than about 10 −8 torr. The purge gas should be chosen as to not readily contaminate the bulk material of the chamber. As one example, high-purity nitrogen may be used as the purge gas to reduce the amount of helium located in the bulk of the material. Processing with a purge gas extends from about about 3×10 2 seconds to about 3×10 7 seconds. Purge gas processing, used on both the interior and exterior of the vacuum chamber material to reduce helium content, is followed by vacuum processing to remove the purge gas from the interior of the vacuum chamber. Purge gas can also be used on the exterior of the vacuum chamber cavity, with vacuum processing being used separately to process the interior of the cavity. Processing with a purge gas on the exterior of the cavity and vacuum processing of the interior of the cavity extends in time from about 3×10 2 seconds to about 3×10 7 seconds.
[0012] One example of a vacuum cell without active pumping is formed with optical windows composed of a transparent material (preferably glass) with helium permeability velocity below about 1×10 −13 cm̂2/s. The windows can be formed into a body structure using a variety of leak-tight bonding techniques including, but not limited to glass fusing, diffusion bonding, anodic bonding or optical contacting. The body structure can be made to have a variety of shapes, including but not limited to, a tube with a round cross section, a tube with a square cross section, or an irregular geometric structure. The body structure can be attached to a metal flange by melting one edge of the glass body and bringing the molten part of the glass in contact with a metal edge. When the assembly is cooled, the interface between the glass and metal forms a leak-tight seal known in the art as a glass-to-metal seal. A target atom injector is placed within the cavity of the cell and can be affixed to the walls of the body structure or affixed to a separate metal flange that then attaches to the flange having the glass-to-metal seal. As an option, the target atom injector may be left unconstrained within the cavity. An atom collector is placed within the cavity of the cell and can be affixed to the walls of the body structure or affixed to a separate metal flange that then attaches to the flange having the glass-to-metal seal. A metal valve may be incorporated into the structure by attaching with a metal flange. The flange need not be removable. Optionally, a metal tube known in the art as a pinchoff tube can be used in place of the metal valve or in addition to the metal valve for sealing the vacuum chamber after sufficient vacuum processing as described above. The valve is closed by rotating a threaded plunger. The pinchoff tube is sealed by squeezing the tube together from the outside until a leak-tight cold weld bond is formed to and the tube is severed.
[0013] Building upon this example, a vacuum cell as above can be constructed that includes a processing port which can be opened and resealed or cut off and replaced. After sufficient operating time has elapsed such that the vacuum quality of the chamber is not favorable, the cell can be “recharged” by attaching it to a vacuum pumping apparatus for reprocessing via the processing port.
[0014] Helium permeation rates can alternatively be reduced by coating the vacuum chamber walls with a material having low helium permeability. Possible mat 1 s include, but are not limited to, graphene and aluminum oxide. The coating may be applied to the inside of the chamber, the outside of the chamber, or both. The coating may be applied prior to, subsequent to, or as part of the vacuum processing described above.
[0015] To complete the process of vacuum processing the vacuum chamber, a final vacuum-tight seal must be made before disconnecting the vacuum chamber from the vacuum pumping apparatus. Prior art shows that a vacuum chamber may be sufficiently sealed using a pinchoff tube that, when squeezed together using a tool, forms a leak-tight cold weld. During the pinch process, the pinchoff tube is severed and the vacuum chamber is freed from the vacuum processing apparatus. In prior art a commercial vacuum valve can be used for a final or intermediate vacuum seal. The vacuum valve consists of a threaded plug that, when turned, seats against a sealing surface to form a vacuum seal. The use of a pinchoff tube and a vacuum valve can be used on vacuum chambers as described above that incorporate a glass-to-metal seal.
[0016] Another way to seal the vacuum chamber is by placing a plug over an evacuation port in the vacuum chamber and then producing a leak-tight bond at the interface between the vacuum chamber and the plug. The bond can be formed using optical contacting. For optical contacting, the plug and a mating surface on the vacuum chamber must have a flatness ranging from about lambda/5 to about lambda/50 and are preferably made from the same material. The surface of the plug and mating surface of the vacuum chamber are thoroughly cleaned prior to processing. After evacuation, the seal is formed by bringing the plug in contact with the mating surface of the vacuum chamber. The movement of the plug relative to the vacuum chamber is accomplished using a vacuum compatible position translator. Heat may be applied at the interface to strengthen the bond. A leak-tight seal is formed.
[0017] If the plug is made of silicon or metal, the seal may be performed using anodic bonding. For anodic bonding, the plug and a mating surface on the vacuum chamber must have a flatness ranging from about lambda/5 to about lambda/50. The surface of the plug and mating surface of the vacuum chamber are thoroughly cleaned prior to processing. A seal based on anodic bonding is performed by bringing the plug in contact with the mating surface of the vacuum cell. The interface is heated using an internal heater to a temperature ranging from about 50 C to about 450 C. Using internal electrodes, a high voltage is applied to the silicon ranging from about 500 volts to about 2000 volts relative to the glass. A leak-tight seal is formed.
[0018] A seal may also be formed using a thin film of indium between the plug and the mating surface of the vacuum cell. After evacuation of the vacuum cell, the plug is brought into contact with the mating surface of the vacuum chamber. The indium film is sandwiched between the plug and mating surface of the vacuum chamber. Heat is applied to the bond interface with an internal heater a leak-tight seal is formed.
[0019] Other aspects of this invention will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 Measurement results of helium permeation for different types of material.
[0021] FIG. 2 a Glass chamber with plug.
[0022] FIG. 2 b Glass chamber with plug and divider.
[0023] FIG. 3 Cell with valve.
[0024] FIG. 4 Glass cell with electrically actuated injector and collector.
[0025] FIG. 5 a (Prior art) Cross-section of window exposed to air on one side and vacuum on the other.
[0026] FIG. 5 b Cross-section of the window during the present invention degassing method using a vacuum.
[0027] FIG. 5 c Cross-section of the window during the present invention degassing method using a purge gas.
[0028] FIG. 5 d Cross-section of the window during the present invention degassing method using a combination of vacuum and purge gas.
[0029] FIG. 6 a Proposed schematic drawing of vacuum chamber processing, degasification and sealing setup.
[0030] FIG. 6 b Proposed schematic drawing of anodic bonding method of sealing plug.
[0031] FIG. 7 Proposed alternate schematic drawing of vacuum chamber processing and degasification setup.
[0032] FIG. 8 Proposed alternate schematic drawing of vacuum chamber processing and degasification setup.
[0033] FIG. 9 Miniature cold atom vacuum chamber.
[0034] FIG. 10 Optically cooled atom instrument.
[0035] FIG. 11 Permeation of helium into processed atom chamber of various materials.
[0036] FIG. 12 Helium barrier coatings on vacuum chamber.
[0037] Before explaining the disclosed embodiment of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown, since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.
DETAILED DESCRIPTION OF THE INVENTION
[0038] Referring first to FIG. 1 the horizontal component represents reciprocal of the absolute temperature in Kelvin times 1000 of the test glass under vacuum in the range of 10 −3 torr to 10 −10 torr. The following prior art glasses were used to construct bulbs and the bulbs were used to characterize the helium permeation velocity (the vertical component) of the materials: one borosilicate glass bulb, one fused silica glass bulb, and three aluminosilicate glass (ASG # 1 , ASG # 2 , ASG # 3 ) bulbs. The size of the bulbs were about spherical in shape with an outer dimension of about 17 mm to about 20 mm with wall thickness of about 0.2 mm to about 1.5 mm. ASG # 1 is Corning(R) 1720 ignition tube glass having 59.2% SiO 2 , 4.6% B 2 O 3 , 22.2% AL 2 O 3 , 4.4% CaO, and 9.9% MgO. ASG # 2 is Schott(R) 8252 aluminosilicate glass. ASG # 3 is Schott(R) 8436 sapphire sealing glass. These aluminosilicate glasses have common uses in constructing high-temperature combustion tubes, producing glass thermometers, and sealing to metal electrodes and flanges as in the case of high temperature halogen light bulbs.
[0039] The present invention begins with an aluminosilicate material including, but not limited to those evaluated above for use as an optical window into a vacuum chamber. The window may alternately use soda lime glass. Referring next to FIG. 2 a , vacuum chamber 20 has size desired from about 100 mm in length to about 1 mm in length and the shape of a cube. Other embodiments could be rectangular with size about 150 mm by about 25 mm as displayed in the figure. The walls 21 can be glass as shown. The walls 21 can be used as an optical window. An aluminosilicate material or soda lime glass as noted above is used as glass 21 . The wall thickness d 1 can range from about 0.1 mm to about 20 mm. Hole 22 is used to evacuate the cavity 26 . The plug 23 is made from a material that can be bonded to glass 21 and can be made from materials including, but not limited to glass, silicon, or metal. Some applications may contain a target atom injector 25 . This target atom injector 25 emits a specified plurality of atoms into the cavity 26 . The specified atom may include, but is not limited to alkali metal atoms or alkali-earth atoms. Some applications may also contain an atom collector 24 .
[0040] The atom collector 24 may be a passive device for collecting impurity atoms in cavity 26 . Prior art atom collectors include devices known in the art as getters. Getters can be of the evaporable or non-evaporable nature. An example of an evaporable getter is a titanium or gold film formed by high temperature vapor deposition. An example of a non-evaporable getter (NEG) is a piece of carbon such as activated charcoal or various forms of graphite. NEG Pumps may also contain a blend of sintered metal powders including zirconium, vanadium, and iron such is commercially sold by SAES(R). Atom collector 24 and target atom injector may be unattached to glass 21 , and left unconstrained in cavity 26 . Atom collector 24 and target atom injector 25 could also be pre-fastened to plug 23 . Atom collector 24 and target atom injector 25 could be films on glass 21 and could be vapor deposited onto glass 21 through hole 22 .
[0041] Referring next to FIG. 2 b , vacuum chamber 220 incorporates a divider 28 that separates the cavity into cavity 26 and cavity 27 . Divider 28 may have fluid communication channel 29 from cavity 26 to cavity 27 . An alternate embodiment (not shown) may have multiple dividers 28 , cavities 26 and 27 , and fluid communications 29 among all of the cavities. Atom collector 24 and atom injector 25 may reside in one or all of the cavities and may also be in separate cavities.
[0042] Referring next to FIG. 3 , vacuum chamber 30 has a different means of sealing its top. A metal flange 32 has an opening 33 . Flange 32 is attached to glass 21 at a glass-to-metal interface 31 . Prior art glass-to-metal seals include a metal cylinder sealed to a glass cylinder. In the prior art, the metals can be chosen to have similar expansion coefficients to that of glass 21 . Port 37 of valve 39 is connected to flange 32 . The valve 39 is constructed to have a threaded plug 34 . Turning threaded plug 34 causes a sealing surface 35 to meet sealing surface 36 forming a vacuum tight seal. Evacuation port 40 exhausts to vacuum source V through pinchoff tube 38 . Pinchoff tube 38 can be sealed by squeezing with a tool. It can later be reopened or replaced to re-apply vacuum to cavity 26 . Atom collector 24 and target atom injector 25 could be optionally fastened to flange 32 . A second lower flange (not shown) could comprise the bottom of the vacuum chamber 30 and support the atom collector 24 and target atom injector 25 .
[0043] Referring next to FIG. 4 , the vacuum chamber 40 has holes in glass 21 suited to seal in wires 44 for the target atom injector 43 and the wires 42 for the atom collector 41 . As is well known in the art, all embodiments of the atom collector and target atom injector may contain electrical wires for electrical activation and operation.
[0044] The shape of the chambers 20 , 220 , 30 , and 40 could have a regular cross-section such as a square, pentagon, hexagon, octagon or circle. Additionally the chambers may have non-regular cross-sections incorporating multiple windows at various angles and may not be prismatic in shape.
[0045] Referring next to FIG. 5 a , vacuum impurities 50 are distributed in the glass 21 . By vacuum impurity we mean impurities that can migrate out of the glass 21 when exposed to a vacuum V, further contaminating cavity 26 . Most dangerous to contaminating the cavity 26 are vacuum impurities 50 consisting of helium atoms which have atomic radius of about 31 picometers and are chemically inert. Materials exposed to air during storage or manufacturing will contain helium atoms 50 . For a sealed and evacuated vacuum cavity 26 , a helium atom 52 from the outside of the chamber OC can migrate through to the inside cavity 26 . The pattern of helium migration through 21 forms a column C of high concentration helium 50 at the air-glass boundary. From column C individual helium atoms 50 can permeate through glass 21 into cavity 26 .
[0046] Referring next to FIG. 5 b , the present invention degassing method is shown. Glass 21 could be an entire container or a segment such as a window for a vacuum chamber. Glass 21 is heated by heat H to a temperature range of about 50 C to about 450 C. Heat H could be applied by radiative heating such as using a laser or a nearby hot body, or by direct contact with a hot body. Helium impurities 50 diffuse out of glass 21 . Vacuum V is simultaneously applied to both sides of the glass thus removing helium 50 from glass 21 . Vacuum V can range from about 10 −4 torr to about 10 −13 torr. This process is continued for between about 3×10 2 seconds to about 3×10 7 seconds. After degassing, a final partial pressure of helium impurities 50 less than about 10 −4 torr is obtained at both of the surfaces of glass 21 .
[0047] Example 1: We used an ASG Corning(R) 1720 glass tube about 25 mm in diameter with a material thickness of about 1.5 mm. The tube was attached at both ends to a glass-to-metal seal. Each seal contained a CF1.33 vacuum flange. A SAES(R) rubidium dispenser model RB/NF/7/25 FT10+10 was used as an atom injector. A SAES(R) non-evaporable getter model ST172/HI/7-6/150C was used as an atom collector. Both the injector and collector were spot welded to a vacuum electrical feedthru on a CF1.33 vacuum flange. The injector/collector assembly was attached to the tube assembly by bolting the CF1.33 flanges together. A vacuum valve from VAT(R) model 54024-GE02 was attached by the CF1.33 flange to the other side of the tube assembly. Furthermore a copper pinchoff tube connected the vacuum valve to the processing pumping apparatus. The apparatus consisted of a UHV turbo pump and a UHV ion pump. The vacuum chamber, not including the processing pumping apparatus, had a volume of about 104 cc. The chamber was heated directly using resistive heating cord and infrared heaters to a temperature of about 250 C for about 4 weeks while the pumping apparatus continued to remove impurities from the chamber. The chamber was then allowed to cool to about 25 C after which, the vacuum valve was closed. The pinchoff tube was then squeezed which had the effect of severing the vacuum chamber from the processing pumping apparatus. Atoms were laser cooled and trapped in the chamber by first applying electrical current of about 2.5 A to the atom injector and then applying three sets of orthogonal pairs of antiparallel laser beams at 780 nm to the volume of the vacuum chamber. A magnetic field gradient was added to the volume using a set of external coils in an anti-Helmholtz configuration. The fluorescence of the atoms was monitored on a photodiode and on a near infrared video camera. The laser cooling was maintained without active pumping.
[0048] Referring next to FIG. 5 c shows an alternate present invention degassing method. Glass 21 could be an entire container or a segment such as a window for a vacuum chamber. Glass 21 is heated by heat H to a temperature range of about 50 C to about 450 C. Heat H could be applied by radiative heating such as using a laser or a nearby hot body, by direct contact with a hot body, or by convective heating with a hot gas. Helium impurities 50 diffuse out of glass 21 . A low helium concentration environment is achieved by applying a high-purity purge gas 51 , as one example nitrogen, simultaneously applied to both sides of the glass thus removing helium 50 from glass 21 . Purge gas 51 must have a helium concentration such that the helium partial pressure in purge gas 51 is less than about 10 −4 torr. The process of applying heat H and purge gas 51 is continued for between about 3×10 2 seconds to about 3×10 7 seconds. After degassing, a final partial pressure of helium impurities 50 less than about 10 −4 torr is obtained at both of the surfaces of glass 21 .
[0049] Referring next to FIG. 5 d shows an alternate present invention degassing method. Glass 21 could be an entire container or a segment such as a window for a vacuum chamber. Glass 21 is heated by heat H to a temperature range of about 50 C to about 450 C. Heat H could be applied by radiative heating such as using a laser or using a nearby hot body, by direct contact with a hot body, or by convective heating with a hot gas. Helium impurities 50 diffuse out of glass 21 . A low helium concentration environment is achieved in cavity 26 by applying vacuum V thus removing helium 50 from glass 21 from the inside of glass 21 . A low helium concentration environment is achieved on the outside of glass 21 by applying a high-purity purge gas 51 , as one example nitrogen, to the outside of the glass 21 thus removing helium 50 from the outside of glass 21 . Purge gas 51 must have a helium concentration such that the helium partial pressure in purge gas 51 is less than about 10 −4 torr. The process of applying heat H, vacuum V and purge gas 51 is continued for between about 3×10 2 seconds to about 3×10 7 seconds. After degassing, a final partial pressure of helium impurities 50 less than about 10 −4 torr is obtained at both of the surfaces of glass 21 .
[0050] Referring next to FIG. 6 a , a proposed degassing and sealing apparatus 60 a is shown. We start with a vacuum enclosure for processing 62 which has an access panel 67 to enable the placement of a vacuum chamber 20 therein. Vacuum enclosure 62 is preferably constructed of stainless steel or aluminum. Panel 67 may incorporate an inspection window (not shown). Panel 67 could also be a gate valve that separates the vacuum enclosure for processing 62 from a sample load-lock enclosure (not shown). A platform 64 anchors vacuum chamber 20 for processing. A plug 23 is removably connected to the plug holder 64 . The plug holder 64 also incorporates a heating element 69 . The plug holder 64 can be moved up and down (see arrows Up, Down) by a position actuator 66 which powers a motional feedthru 65 . Position actuator could be a manually driven screw, an electric motor, or pneumatic actuator. Alternately, plug holder 64 could be manipulated by a electrically actuated translation stage (not shown) internal to the processing chamber. Vacuum pump V has a fluid communication 61 with the process chamber 63 . For processing, the vacuum at 63 ranges from about 10 −6 torr to about 10 −13 torr. The aluminosilicate glass 21 is from about 0.1 mm to about 10 mm in thickness and we predict a processing time interval ranging from about 3 days to about 3 months. During this vacuum processing time interval the vacuum chamber 20 is heated by heater 69 in the platform 64 . Alternately the vacuum enclosure for processing 62 could be heated externally (not shown). The temperature of vacuum chamber 20 is maintained at a value ranging from about 50 C to about 450 C, during the processing time interval. At the end of the helium impurity 50 evacuation process, the plug 23 sealing operation begins.
[0051] Plug 23 is preferably made out of the same type of material as the glass 21 . The mating surfaces 68 of the vacuum chamber 20 and the plug 23 have been prepared to a flatness ranging from about lambda/5 to about lambda/50 where lambda is 633 nm prior to placement into degassing and sealing apparatus 60 a . The surfaces of plug 23 and mating surfaces 68 may be cleaned with an acid such as HF or a base such as KOH prior to placement into degassing and sealing apparatus 60 a . Plug 23 is lowered against the mating surface 68 of vacuum chamber 20 using the position actuator 66 . The heater 69 in plug holder 64 is actuated to a temperature of about 50 C to about 450 C. The heater 69 has the effect of raising the temperature of the glass 21 at mating surface 68 to a value ranging between 50 C and 450 C. The temperature is sustained for a time ranging between about 3 hours to about 3 days. At that point the vacuum chamber 20 can be removed and used for application including, but not limited to, optical cooling of atoms, magnetic sensing, gravitational sensing, and quantum information. It is estimated that a commercially viable vacuum chamber 20 may range from about 1 cubic mm to about 1 liter. After vacuum processing, the outside of glass 21 (of chamber 20 ) may be machined to reshape or true the outer surfaces using common glass grinding and polishing techniques known in the art.
[0052] Referring next to FIG. 6 b , the processing and degassing apparatus 60 b has a positive charged conductor 71 that passes through the insulator 70 to the plug holder 64 which is electrically conductive. A conductive wire 72 at a lower potential such as ground may pass through an insulator 70 and connect to an electrode 73 that is in physical contact with glass 21 on or adjacent to mating surface 68 . Alternately, the insulator 70 can be eliminated and conductive wire 72 may connect to directly to the inside of vacuum enclosure 62 if the potential on vacuum enclosure 62 is maintained near about ground (not shown). Plug 23 S is preferably made from silicon. The mating surfaces 68 of the vacuum chamber 20 and the plug 23 S have been prepared to a flatness ranging from about lambda/5 to about lambda/50 prior to placement into degassing and sealing apparatus 60 b . The surfaces of plug 23 S and mating surfaces 68 may be cleaned with an acid such as HF or a base such as KOH prior to placement into degassing and sealing apparatus 60 b . When the plug 23 S is pressed into contact with the surface 68 , the circuit is completed wherein a current flows from the plug holder 64 through the glass 21 to the electrode 73 and back through the conductive wire 72 . Heat is applied through heater 69 raising the mating surface 68 to a temperature ranging from about 100 C to about 450 C. The voltage applied to conductor 71 ranges from about 500 volts to about 2000 volts. It is estimated that a time period ranging between about 5 minutes and about 1 hour is needed to complete a leak-tight bond. This process is known as anodic bonding. See US patent number U.S. Pat. No. 7,807,509 B2 incorporated herein by reference. See especially FIG. 2 a.
[0053] Referring next to FIG. 6 c , an indium film 601 is deposited onto mating surface 68 . The indium film 601 may be in the form of an indium foil ranging in thickness from about 0.020 mm to about 1 mm. Indium film 601 may also be applied previously to mating surface 68 using vapor deposition or by electroplating (both techniques being known in the art) with indium thickness ranging from about 0.005 mm to 0.1 mm. For vapor deposition or electroplating, a metal base layer may be used composed from a combination of metals, including, but not limited to Cu, Ag, Au, Cr, Mo, and W. The process of degassing material 21 is the same as described above. Plug 23 is lowered against the indium film 601 on mating surface 68 of vacuum chamber 20 using the position actuator 66 . The heater 69 in plug holder 64 is actuated to a temperature of about 50 C to about 250 C. The heater 69 has the effect of raising the temperature of the glass 21 at mating surface 68 to a value ranging between 50 C and 250 C. The temperature is sustained for a time ranging between about 10 minutes to about 10 hours.
[0054] Referring next to FIG. 7 , shown is the present invention vacuum processing and degassing apparatus 80 . Vacuum chamber embodiment 30 as described above is incorporated into vacuum processing apparatus 80 . We start with a vacuum enclosure 81 for processing which has an access panel 67 to enable the placement of a vacuum cell 30 therein. Vacuum enclosure 81 is preferably constructed of stainless steel or aluminum and is heated from the outside by a heater (not shown). Panel 67 may incorporate an inspection window (not shown). At least one vacuum pump V has fluid connection 83 through vacuum port 82 to pinchoff tube 38 . Vacuum pump V has fluid connection 84 to process vacuum space 63 . Vacuum pump V could be bifurcated or two separate pumps. The procedure for degassing glass 21 is the same as described above in FIG. 6 a and FIG. 5 b . The aluminosilicate glass 21 is from about 0.1 mm to about 10 mm in thickness and we predict a processing time interval ranging from about 3 days to about 3 months. During this vacuum processing time interval the vacuum chamber 20 is heated indirectly by heating the vacuum enclosure 81 from the outside with a resistive or radiative heater (not shown) or a flame. The temperature of the enclosure 81 is maintained at a value ranging from about 50 C to about 450 C, during the processing time interval. Enclosure 81 heats apparatus 30 indirectly from heat conducted through pinchoff tube 38 and heat radiated inward from the walls of enclosure 81 . At the end of the helium impurity 50 evacuation process, the outer volume 63 is returned to ambient pressure. The access panel 67 is removed. The valve 39 is closed. The pinchoff tube 38 is closed. The apparatus 30 is removed and ready for service.
[0055] Apparatus 30 can reevacuated at a later time. The used pinchoff tube 38 is removed and replaced. Apparatus 30 is replaced into the processing and degassing apparatus 80 through access panel 67 . The open end of the pinchoff tube 38 is sealed to port 82 . Vacuum V is activated, the valve 39 is opened, and access panel 67 is closed. The evacuation process is repeated as described above.
[0056] Next referring to FIG. 8 , apparatus 30 is placed into a purge gas enclosure 95 . Enclosure 95 incorporates a port 91 . A purge gas supply GAS, injects a desired purge gas 51 into volume 92 via inlet tube 93 . Excess purge gas 51 and helium impurities 50 exhaust through port 91 . Purge gas 51 may be a number of gases including, but not limited to nitrogen, argon, CO2, as anyone skilled in the art may select. Purge gas 51 must be pure of helium. All other process variables are as described in FIG. 7 .
[0057] Referring next to FIG. 9 a , a bar 100 composed primarily of glass is made from a base 101 , spacer 102 , spacer 103 and a top 104 . Base 101 , spacer 102 , spacer 103 and a top 104 can range in length from about 5 mm to about 200 mm. Base 101 , spacer 102 , spacer 103 and a top 104 can range in thickness from about 0.1 mm to about 20 mm. Base 101 , spacer 102 , spacer 103 , top 104 may be composed exclusively or in part by glass 21 . Spacer 102 and spacer 103 are placed on base 101 . Top 104 is placed on spacer 102 and spacer 103 forming a channel 105 . Adjoining surfaces 130 are bonded together. One of a variety of bonding techniques can be used including, but not limited to, optical contact bonding, chemically assisted optical contact bonding, anodic bonding, or direct diffusion bonding. To one skilled in the art of glass bonding, these are all known techniques. Adjoining surfaces 130 and cavity surfaces 131 are previously prepared before bonding to be flat ranging from about lambda/5 to about lambda/50 using standard glass polishing techniques known in the art. Lambda is 633 nm.
[0058] Referring next to FIG. 9 b , a bar 100 is cut along line 104 forming in FIG. 9 c , a slice 110 . Exposed front and back surfaces 106 , which have a normal vector along the direction of channel 105 , are polished to a flatness ranging from about lambda/5 to about lambda/50.
[0059] Referring next to FIG. 9 d , a cap 111 is bonded to one exposed surface 106 to form chamber 140 . Cap 111 may be composed exclusively or in part by glass 21 . One of a variety of bonding techniques can be used including, but not limited to, optical contact bonding, chemically assisted optical contact bonding, anodic bonding, or direct diffusion bonding.
[0060] Referring next to FIG. 9 e , assembly 140 is placed into a processing apparatus such as degassing and sealing apparatus 60 a or 60 b as shown in FIGS. 6 a , 6 b . A plug 23 is removably connected to the plug holder 64 . Plug 23 may be composed exclusively or in part by glass 21 . The plug holder 64 can be moved up and down by a motional feedthru 65 . Vacuum processing, degassing, and sealing is performed the same as described in FIG. 6 a or FIG. 6 b . One way of forming the embodiment 220 of FIG. 2 b would be to us a plug 23 (not shown) that has a hole in it which would form fluid communication channel 29 . Next another chamber 140 would be attached over the plug 23 with the hole to form the multiple chamber embodiment 220 of FIG. 2 b.
[0061] Referring next to FIG. 9 f , chamber 140 is removed from the processing apparatus such as degassing and sealing apparatus 60 a or 60 b . Chamber 120 is machined along cut lines CL 1 , CL 2 , CL 3 , and CL 4 using standard glass machining techniques such as glass sawing or glass grinding which are known in the art. Additional cut lines (not shown) may also be performed. Rough surfaces such as those along cut lines CL 1 , CL 2 , CL 3 , and CL 4 may be polished to an optical flatness ranging from about lambda/1 to about lambda/50 using standard glass polishing techniques known in the art. Other surfaces of chamber 140 may also be polished.
[0062] Referring next to FIG. 9 g , executing the cut lines as noted in FIG. 9 f results in the vacuum chamber 150 . Cavity 151 may have a volume as small as about 0.001 mm 3 or as large as about 8 cm 3 . The wall thickness may be as small as about 0 . 001 mm or may be as large as about 200 mm. Applications can include optical wavelength references, a container for optically cooled atoms, inertial sensors, gravity sensors, magnetic field sensors, atomic clocks, and atomic oscillators.
[0063] Example 2: We constructed micro vacuum chambers from fused silica glass. We started with four pieces; a bottom, a top, and two spacers. The bottom piece was 100 mm wide, 40 mm long, and 2 mm thick. The top piece had the same dimensions. The two spacers were each 4 mm wide, 40 mm long, and 2 mm thick. The pieces were polished to better than lambda/10 at surfaces that were to undergo bonding. Two different bonding methods were used. In one case we used optical contact bonding. The pieces were cleaned thoroughly using solvents, acetone, IPA, and a basic cleaning agent KOH, and water. The spacers were stacked onto the bottom piece leaving a uniform gap between the spacers. An optical contact bond was formed by applying pressure by hand at the bond joint. The top was then stacked onto the spacers forming a bar with an open channel. Once again, an optical contact bond was formed. In another case we repeated these steps, but substituted optical contact bonding with diffusion bonding. The stacks were aligned and placed into an oven. In the oven, pressure of about 6 to ten PSI was applied to the stack while the temperature was raised to about 1100 C for 6 Hours. This temperature was chosen to be about near the strain point of the glass and not exceed the softening point of the glass. After bonding, the bar was cut into slices that were 2 mm thick. The front and back faces of the slices were polished to a flatness of about lambda/10. Flat windows measuring 6 mm, by 8 mm, by 2 mm thick were bonded over the channel using both bonding techniques forming a sealed cavity. In the case of those that were bonded using diffusion bonding, a vacuum was created inside the cavity due to expansion and contraction of the gas that filled the cavity during heating and cooling. The assembly was cut along planes parallel to surfaces that form the cavity. The cut planes were then polished. The final micro vacuum chambers measured 4 mm×4 mm×4 mm, with an internal cavity that measured 2 mm×2 mm×2 mm.
[0064] Referring next to FIG. 10 , a cold atoms instrument 1000 consists of crossed laser beams 1001 that meet about near the center a vacuum chamber such as 20 shown in FIG. 2 . The crossed laser beams 1001 can have a typical intensity ranging from about 1 mW/cm 2 to about 100 mW/cm 2 . Vacuum chamber 20 can be substituted with vacuum chamber 30 , vacuum chamber 40 , or vacuum chamber 140 as described earlier. Target atom injector 25 is actuated to dispense target atoms into the volume of the vacuum chamber 20 . A set of magnetic coils (not shown) provide a magnetic field gradient ranging from about 1 Gauss/cm to about 100 Gauss/cm. A collection of cooled atoms 1003 forms where the crossed laser beams 1001 intersect. The collection of cooled atoms 1003 can be adjusted from about 1 atom to about 10 10 atoms by varying the intensity of the crossed laser beams 1001 and the magnetic field gradient at the location of the atoms. Background atom collector 24 helps to maintain low operating pressures. A probe laser 1002 addresses the collection of cooled atoms 1003 . A detector 1004 is used to sense light emitted or absorbed by the collection of cooled atoms 1003 . The temperature of the collection of cooled atoms 1003 can range from about 1 millikelvin to about 0.1 nanokelvin. Various properties of the collection of cooled atoms 1003 can be measured including, but not limited to, the number of atoms, the atom temperature, the atoms' quantum state, the pressure in the vacuum chamber 20 , magnetic energy shifts, energy shifts related to inertial excitement of the atoms, quantum phase, and energy of atomic levels. An example is shown that the flux density of magnetic field B may be measured.
[0065] Referring next to FIG. 11 , the horizontal component represents a time delay in days. The graph represents the accumulation of helium in a closed glass vacuum chamber as a function of time. The helium partial pressure is plotted on the vertical component for glass vacuum chambers where the glass has been properly degassed as described above. The calculation is performed for glass vacuum chambers constructed from three different glass types and having a size of 3.5 cm×3.5 cm×5 cm and window thickness of 2. Dashed line 1101 shows helium partial pressure inside the chamber as a function of time for a vacuum chamber made from borosilicate glass. Dotted line 1102 shows helium partial pressure inside the chamber as a function of time for a vacuum chamber made from soda-lime silica glass. Solid line 1103 shows helium partial pressure inside the chamber as a function of time for a vacuum chamber made from aluminosilicate glass. A typical pressure at which optical cooling begins to fail is about 10 −8 torr. Setting this as our failure criteria, dashed line 1101 shows that the present invention constructed from borosilicate glass would have a device lifetime of about 10 days. Dotted line 1102 shows that the present invention constructed from soda-lime silica glass would have a device lifetime of about 450 days. Solid line 1103 shows that the present invention constructed from aluminosilicate glass would have a device lifetime of about 4500 days.
[0066] Referring next to FIG. 12 , a vacuum chamber 1200 may be constructed from a variety of types of glass 1203 , including those that have a high helium permeability. Helium permeation rates may be reduced by depositing a coating 1201 , with low helium permeability, onto the outside of glass 1203 and plug 23 . Coating 1202 , with low helium permeability, may be deposited to the inside of glass 1203 and plug 23 . Possible coating materials for coatings 1201 and 1202 include, but are not limited to, graphene and aluminum oxide. The coatings may be applied to the inside of the vacuum chamber 1200 , to the outside of the vacuum chamber 1200 , or to both. The coating may be deposited prior to, subsequent to, or as part of the vacuum processing described above. Coatings 1201 and 1202 can range in thickness from 0.335 nm to 0.1 mm. The coatings 1201 and 1202 may be deposited using wet chemistry techniques such as dip coating which is known in the art. Alternately, the coatings may be deposited using vapor deposition which is known in the art. The evacuation and sealing method noted above would remain the same to utilize vacuum chamber 1200 .
[0067] Although the present invention has been described with reference to the disclosed embodiments, numerous modifications and variations can be made and still the result will come within the scope of the invention. No limitation with respect to the specific embodiments disclosed herein is intended or should be inferred. Each apparatus embodiment described herein has numerous equivalents. | The present invention discloses a vacuum chamber having operating pressures in the ultra-high vacuum (UHV) range (10 −8 torr to 10 −13 torr) and incorporating transparent windows, said windows constructed from transparent materials (preferably glass), and having low helium permeability velocity under operating and storage conditions. Embodiments may also contain surface coatings on windows to reduce helium permeation. Also disclosed herein is a method for vacuum processing said chamber by heating entire chamber and exposing the inside and outside of the chamber windows to helium free environments. Methods for final sealing said chamber are also discussed. The vacuum chamber is useful as a container for optically-cooled atoms for use in quantum information and atomic clocks and as a sensor for magnetic fields, gravitational fields, and inertial effects. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 12/137,732, filed Jun. 12, 2008, which claims the benefit of priority from U.S. Provisional Application No. 60/943,397, filed Jun. 12, 2007, the disclosures of which are hereby incorporated in its entirety by reference thereto.
TECHNICAL FIELD
[0002] Embodiments of the present invention relate to syringe assemblies having a passive locking mechanism which restricts distal movement of the plunger rod after injection to prevent reuse, syringe assemblies wherein the stopper and plunger rod operate using relative motion to passively disable the syringe, syringe assemblies including a removeably connected stopper and plunger rod to prevent disassembly of the syringe prior to use and syringe assemblies including visual indication or markings to indicate use of the syringe or a disabled syringe.
BACKGROUND
[0003] Reuse of hypodermic syringe products without sterilization or sufficient sterilization is believed to perpetuate drug abuse and facilitate the transfer of contagious diseases. The reuse of syringes by intravenous drug users further exacerbates the transfer of contagious diseases because they comprise a high-risk group with respect to certain viruses such as the AIDS virus and hepatitis. A high risk of contamination also exists in countries with shortages of medical personnel and supplies.
[0004] A syringe which can be rendered inoperable after use presents a viable solution to these issues. Various syringes have been proposed and are commercially available that can be disabled by the user by taking active steps to disable the syringe. Single-use syringes that do not require the user to actively disable the syringe are also thought to offer a solution. It would be desirable to provide syringes that are automatically or passively disabled from reuse and can be manufactured in a cost-effective manner by, for example, utilizing fewer parts. Further, markings or other indicators which visually indicate whether a syringe has been used or is disabled would also be desirable.
SUMMARY
[0005] A passive disabling system for a syringe assembly that activates after completion of an injection cycle is provided. A syringe assembly incorporates a stopper and plunger rod attached in a manner to prevent users from disassembling the syringe prior to completion of the injection cycle. In one or more embodiments of the invention, a user can fill, inject and/or reconstitute medication.
[0006] In this disclosure, a convention is followed wherein the distal end of the device is the end closest to a patient and the proximal end of the device is the end away from the patient and closest to a practitioner.
[0007] A syringe assembly is provided which includes a barrel, an elongate plunger rod and stopper having respective structures and assembly which allow the user to passively lock the plunger rod within the barrel to prevent reuse of the syringe assembly. The barrel includes a distal end, an open proximal end, a cylindrical sidewall with an interior surface, which defines a chamber in which fluid may be held, and a distal wall. An opening in the distal wall permits fluid to flow from the chamber through the opening. In one embodiment, the barrel includes a marker or indicator which indicates whether the syringe has been disabled or the plunger has been locked within the barrel.
[0008] In one or more embodiments, the interior surface of the sidewall of the barrel has a continuous diameter or first inner diameter. As used throughout this application, the term “diameter” is a measurement of the longest distance between the walls of the barrel having any cross-sectional shape. However, it will be appreciated that conventional syringes are typically cylindrical with a circular cross-sectional shape. In accordance with some embodiments of the present invention, the barrel includes a rib, locking rib or other such impediment suitable for restricting the proximal movement of the plunger rod, adjacent to its proximal end. In one embodiment, the rib has a second inner diameter, wherein the second diameter is less than the first diameter. One or more embodiments of the present invention include an increased diameter region located proximally from the rib having a third inner diameter, wherein the third diameter is greater than the first diameter and second diameter. A diameter transition region or a ramp having an axial length located between the rib and the increased diameter region may be included. The diameter transition region or ramp can have a varying inner diameter, which increases in the proximal direction.
[0009] Embodiments of the present invention also include an extended plunger rod which has a proximal end, a distal end, and a main body between the proximal and distal end. A thumb press may also be disposed at the proximal end of the plunger rod. In some embodiments, the plunger rod slides or otherwise moves proximally and distally within the chamber of the barrel.
[0010] The distal end of the plunger can include a stopper-engaging portion having a distal and proximal end. Alternative embodiments further include an optional disc disposed at the distal end of the plunger rod between the main body and the stopper engaging portion of the plunger rod and/or between the main body and the flexible protrusion (described below). The stopper-engaging portion provides a means for the stopper and plunger rod to move proximally and distally within the barrel. In one or more embodiments, the stopper-engaging portion allows the stopper and plunger rod to move proximally and distally relative to each other. In a specific embodiment, the distal end of the stopper-engaging portion may include a rim, retainer, retaining ring or alternate means suitable for restraining the stopper. The stopper-engaging portion according to one or more embodiments may also include a visual indicator or a visual display that indicates use of the syringe or whether the syringe is disabled.
[0011] The plunger rod can further include means for locking the plunger rod in the barrel to prevent reuse of the syringe assembly when the syringe is fully injected or “bottomed.” As used herein, the term “bottomed” shall refer to the position of the syringe assembly wherein the stopper, while attached to the plunger rod, is in contact with the distal wall of the barrel and the plunger rod can no longer move in the distal direction. As used herein, the term “activation force” shall mean the force required to bottom the syringe or the force required to move the plunger rod in the distal direction such that the stopper is in contact with the distal wall of the barrel and can no longer move in the distal direction. For example, application of the activation force to the thumb press in the distal direction “activates” or causes the means for locking the plunger rod to move distally past the rib of the barrel. The means for locking the plunger rod can have an outer diameter greater than the inner diameter of the barrel at the rib or the second inner diameter. One or more embodiments of the present invention utilize a protrusion, or annular protrusion that extends radially from the plunger rod as a means for locking the plunger rod. In some embodiments, the protrusion is located between the thumb press and the main body and is an example of a means for locking the plunger rod in the barrel. According to an embodiment of the invention, the protrusion is integrally molded to the plunger rod. The protrusion according to one or more embodiments may be rigid or flexible. Embodiments utilizing a flexible protrusion may further include a support adjacent to the flexible protrusion.
[0012] In one configuration, the protrusion has an outer diameter greater than the second inner diameter or the diameter of the barrel located at the rib. Once the protrusion distally moves through the diameter transition region, past the rib and into the barrel, it becomes locked by the rib and the plunger rod is prevented from moving in the proximal direction. The protrusion of one embodiment is tapered or otherwise shaped in such a manner such that it may move in the distal direction past the rib more easily. In embodiments utilizing a flexible protrusion, the protrusion may facilitate distal movement of the plunger rod by flexing in the proximal direction as a force is applied to the plunger rod in the distal direction. In one embodiment, the flexible protrusion also flexes as the plunger rod is moved in the distal direction past the rib. The diameter transition region or ramp of the barrel may further facilitate distal movement of the plunger rod. In such embodiments, the ability for the flexible protrusion to flex and the plunger rod to move in the proximal direction may be limited after the flexible protrusion has moved distally past the rib.
[0013] The plunger rod can further comprise at least one frangible portion or other means for separating a portion of the plunger rod from the body. In this configuration, when a user attempts to reuse the syringe assembly or otherwise pull the plunger in the proximal direction out of the barrel, after the plunger rod has been locked, the plunger rod breaks at the frangible portion, leaving a portion of the plunger rod locked within the barrel. In a specific embodiment, the frangible portion is located between the protrusion and the thumb press. It will be appreciated that the frangible portion can be located in various locations near the proximal end of the plunger rod. In one embodiment, the frangible portion comprises a narrowed frangible connection or a frangible bridge having a dimension that is at least about 50% less than the overall dimension of the plunger rod. More particularly, the dimension can be either the diameter or the width of the plunge rod. In a more specific embodiment, the frangible portion includes a plurality of frangible connections or bridges, which may further include two or more point connections. The plurality of frangible connections or bridges are adapted to withstand application of a force on the plunger rod in the distal direction and to break upon application of a force in the proximal direction after the flexible protrusion has advanced distally past the rib or the syringe has been bottomed.
[0014] In a specific embodiment, the term “deactivation force” includes the force required to separate a portion of the plunger rod from the body and the term “withdrawal force” includes the force needed to move the plunger rod in the proximal direction after the syringe has been bottomed or the plunger rod has been locked in the barrel by the rib. In a more specific embodiment, the withdrawal force is greater than the deactivation force and the activation force.
[0015] The stopper has a proximal end and a distal end and the stopper is attached the stopper-engaging portion of the plunger rod. In some embodiments, the stopper moves distally and proximally within the barrel. In one or more embodiments, the stopper also moves distally and proximally along a pre-selected axial distance relative to the stopper-engaging portion of the plunger rod, thereby allowing the protrusion to move distally past the rib into the locked position when the syringe assembly is bottomed.
[0016] The stopper may further comprise a stopper body or stopper boss at the proximal end of the stopper. A peripheral lip may be included at the proximal end of the stopper body. A frangible link may be provided to connect the stopper to the plunger rod, which may connect the stopper and the peripheral lip. Alternative means for separating the stopper from the plunger rod or to destroy the stopper may also be provided.
[0017] In one embodiment, when a user aspirates or fills the syringe assembly, the stopper begins to move in the proximal direction in tandem with the plunger rod, while maintaining the pre-selected axial distance. An optional visual indicator or display disposed on the stopper-engaging portion of the plunger rod is visible when the user fills the syringe assembly. In one or more embodiments of the present invention, when a user injects the contents of the syringe assembly, the attachment of the stopper and the stopper-engaging portion allow the plunger rod to move distally for a length of the pre-selected axial distance, while the stopper remains stationary. After the plunger rod travels distally for the length of the pre-selected axial distance, the stopper begins to move distally with the plunger rod. During such distal movement, where a visual indicator or display is utilized, the visual indicator or display disposed on the stopper-engaging portion of the plunger rod is no longer visible. Where a visual marker is utilized, the visual marker disposed on the barrel continues to be visible, even after the plunger rod is locked. As will be more fully described herein, the marker provides an alternative means of indicating the syringe has been disabled.
[0018] According to one embodiment of the present invention, the total length of the plunger rod is decreased by pre-selected axial distance when the stopper and plunger rod move together in the distal direction during injection of the contents of the syringe assembly. As such, the stopper and stopper-engaging portion of the syringe assembly are attached in a manner such that when a user has fully completed the injection cycle, the protrusion of the plunger rod advances past the rib of the barrel. In some embodiments, once the protrusion advances past the rib of the barrel, it locks the plunger rod within the barrel and prevents the user from reusing the syringe assembly or otherwise pulling the plunger rod out of the barrel. Once the plunger rod is locked within the barrel, the optional visual indicator or display on the stopper-engaging portion of the plunger rod is no longer visible, indicating the syringe has been disabled.
[0019] According to an alternative embodiment, the stopper and the plunger rod are connected in a fixed relationship such that when the distal end of the stopper is contact with the distal wall of the barrel, the flexible protrusion is permitted to advance distally past the rib in the barrel. In embodiments utilizing a stopper and plunger rod having a fixed relationship, the pre-selected axial distance is zero and application of a continuous force in the proximal direction during aspiration or filling causes the stopper and plunger rod move together. In the initial position as supplied or packaged, the stopper is not in contact with the distal wall of the barrel and, instead, there is a gap between the distal end of the barrel and the distal wall of the barrel. In such embodiments, the user may fill the barrel of the syringe to accommodate the initial gap between the stopper and the distal wall of the barrel. The user may thereafter expel the air present in the barrel from the presence of the gap before injecting the contents of the syringe. During injection and application of a force in the distal direction to the plunger rod, the fixed stopper and plunger rod move together until the stopper reaches the distal end of the barrel and the protrusion is permitted to advance distally within past the rib of the barrel.
[0020] The syringe assembly may include one or more frangible portions of the plunger rod, which break when a user attempts to move the plunger rod in a proximal direction after the protrusion has advanced past the rib of the barrel. Other suitable means may be utilized for separating a portion of the plunger rod from the main body when the user applies sufficient proximal force to the plunger rod or otherwise attempts to reuse the syringe assembly after it is bottomed.
[0021] In accordance with one embodiment of the invention, the stopper and the stopper-engaging portion are attached in such a manner such that when a user attempts to disassemble the syringe assembly prior to aspiration, injection or bottoming, the stopper-engaging portion disengages from the stopper, leaving the stopper inside the barrel and allowing the separated plunger rod to be removed. In some embodiments, inner diameter of the barrel at the rib, or the second inner diameter, is less than the outer diameter of the stopper, and thereby prevents the stopper from moving proximally past the rib and causes the stopper-engaging portion to detach from the stopper, leaving the stopper inside the barrel. An optional frangible link of the stopper breaks when a user attempts to disassemble the syringe assembly by applying a continuous force in the proximal direction to the plunger rod prior to aspiration, injection or bottoming.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 illustrates a perspective view of a syringe assembly according to an embodiment of the invention shown;
[0023] FIG. 2 illustrates a disassembled perspective view of a syringe assembly according to an embodiment of the invention;
[0024] FIG. 3 shows a cross-sectional view of the barrel shown in FIG. 2 taken along line 3 - 3 ;
[0025] FIG. 4 is an enlarged view of a portion of the barrel shown in FIG. 3 ;
[0026] FIG. 5 is a cross-sectional view of the stopper shown in FIG. 2 taken along line 5 - 5 ;
[0027] FIG. 6 is a cross-sectional view of the plunger rod shown in FIG. 2 taken along line 6 - 6 ;
[0028] FIG. 7 is a cross-sectional view taken along line 7 - 7 of FIG. 1 ;
[0029] FIG. 8 is an illustration of FIG. 7 showing the plunger rod being moved in the proximal direction;
[0030] FIG. 9 is an illustration of FIG. 8 showing the plunger rod being moved in the distal direction;
[0031] FIG. 10 is an illustration of FIG. 9 showing the plunger rod in a locked position in the syringe barrel;
[0032] FIG. 11 is an enlarged view of a proximal portion of the assembly shown in FIG. 10 ;
[0033] FIG. 12 illustrates a perspective view of an embodiment of a syringe assembly having a visual marker disposed on the barrel;
[0034] FIG. 13 illustrates a disassembled perspective view of an embodiment of a syringe assembly with visual indicators or markers disposed on the barrel and the stopper-engaging portion of the plunger rod;
[0035] FIG. 14 is a cross-sectional view taken along line 14 - 14 of FIG. 12 ;
[0036] FIG. 15 is an illustration of FIG. 14 showing the plunger rod in a locked position in the syringe barrel;
[0037] FIG. 16 is an enlarged view of a proximal portion of the assembly shown in FIG. 15 ;
[0038] FIG. 17 is an illustration of FIG. 10 showing a proximal portion of the plunger rod being broken from the syringe assembly after the plunger rod has been locked in the syringe barrel;
[0039] FIG. 18 is an illustration of FIG. 7 showing the plunger rod being moved in the proximal direction and the stopper disengaging from the plunger rod;
[0040] FIG. 19 a disassembled perspective view of a syringe assembly according to another embodiment of the invention;
[0041] FIG. 20 is a perspective view of the plunger rod shown in FIG. 19 ;
[0042] FIG. 21 is a side elevational view of the stopper shown in FIG. 19 ;
[0043] FIG. 22 is a cross-sectional view taken along line 22 - 22 of the syringe assembly shown in FIG. 19 ;
[0044] FIG. 23 is an illustration of FIG. 22 showing the plunger rod being moved in the proximal direction;
[0045] FIG. 24 is an illustration of FIG. 23 showing the plunger rod being moved in the distal direction;
[0046] FIG. 25 is an illustration of FIG. 24 showing the plunger rod in a locked position in the syringe barrel;
[0047] FIG. 26 is an illustration of FIG. 25 showing a proximal portion of the plunger rod being broken from the syringe assembly after the plunger rod has been locked in the barrel;
[0048] FIG. 27 is an illustration of FIG. 22 showing the plunger rod being moved in the proximal direction and the stopper disengaging from the plunger rod;
[0049] FIG. 28 shows a disassembled perspective view of a syringe assembly according to another embodiment of the invention;
[0050] FIG. 29 shows a cross-sectional view of the barrel shown in FIG. 28 taken along line 29 - 29 ;
[0051] FIG. 30 is an enlarged view of a portion of the barrel shown in FIG. 29 ;
[0052] FIG. 31 is a cross-sectional view of the stopper shown in FIG. 28 taken along line 31 - 31 ;
[0053] FIG. 32 illustrates a perspective view of the plunger rod shown in FIG. 28 ;
[0054] FIG. 33 is a cross sectional view of the plunger rod shown in FIG. 28 taken along lines 33 - 33 ;
[0055] FIG. 34 is a cross-sectional view taken along line 34 - 34 of the syringe assembly shown in FIG. 28 ;
[0056] FIG. 35 is an illustration of FIG. 34 showing the plunger rod being moved in the proximal direction;
[0057] FIG. 36 is an illustration of FIG. 35 showing the plunger rod being moved in the distal direction;
[0058] FIG. 37 is an illustration of FIG. 36 showing the plunger rod in a locked position in the syringe barrel;
[0059] FIG. 38 is an enlarged view of a proximal portion of the assembly shown in FIG. 37 ;
[0060] FIG. 39 is an illustration of FIG. 37 showing a proximal portion of the plunger rod being broken from the syringe assembly after the plunger rod has been locked in the barrel; and
[0061] FIG. 40 is an illustration of FIG. 34 showing the plunger rod being moved in the proximal direction and the stopper disengaging from the plunger rod.
DETAILED DESCRIPTION
[0062] Before describing several exemplary embodiments of the invention, it is to be understood that the invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or being carried out in various ways.
[0063] One aspect of the present invention provides for a syringe assembly including a barrel, plunger rod and stopper having individual features and construction which allow the user to passively lock the plunger rod within the barrel to prevent reuse of the syringe assembly.
[0064] FIG. 1 shows a syringe assembly 100 according to one or more embodiments. As shown in FIG. 2 , the syringe assembly includes a barrel 120 , a plunger rod 140 and a stopper 160 , arranged such that the proximal end 169 of stopper is attached to the distal end 141 of the plunger rod. The connected stopper 160 and plunger rod 140 are inserted into the proximal end 129 of the barrel 120 .
[0065] As best shown in the FIG. 3 , the barrel 120 has a cylindrical sidewall 110 with an interior surface 126 that defines a chamber 128 . In one embodiment, the chamber 128 holds the contents of the syringe assembly which may include medication in powdered or fluid form. The barrel 120 is shown as having an open proximal end 129 , a distal end 121 , and a distal wall 122 . The distal wall 122 has an opening 111 in fluid communication with the chamber 128 .
[0066] The sidewall 110 of the barrel 120 defines a chamber having a continuous inner diameter along the longitudinal axis of the syringe. Alternatively, the barrel can include a sidewall has an inner diameter, which decreases linearly from the proximal end to the distal end. It is to be understood that the configuration shown is merely exemplary, and the components can be different in shape and size than shown. For example, the barrel can have an exterior prism shape, while retaining a cylindrical interior shape. Alternatively, both the exterior and interior surfaces of the barrel can have non-circular cross-sectional shapes.
[0067] The syringe barrel 120 is shown as having a peripheral flange 124 attached at the proximal end 129 of the barrel 120 . The barrel 120 further includes a needle cannula 150 , having a lumen 153 attached to the opening 111 in the distal wall 122 of the barrel 120 . As is known in the art, attachment means 152 is provided for attaching the needle cannula 150 to the distal wall 122 . The assembly 100 may also include a protective cap over the needle cannula (not shown).
[0068] As shown more clearly in FIG. 4 , the barrel 120 further includes a rib 123 adjacent its proximal end 129 . The inner diameter of the barrel at the location of the rib 123 is smaller than the inner diameter of the barrel 120 at other locations along the length of the barrel. One or more optional tabs or detents can be used to create a region of the barrel having a diameter smaller than the inner diameter of the barrel 120 . In a specific embodiment, the rib can include a ring formed along entire circumference of the interior surface 126 or a portion of the interior surface 126 of the inner diameter of the barrel 120 (not shown). The barrel 120 also includes a diameter transition region 127 adjacent to the rib 123 at the proximal end 129 (as shown in FIG. 3 ) of the barrel 120 . The inner diameter of the barrel at the diameter transition region 127 increases from the distal end 121 to the proximal end 129 (as shown in FIG. 3 ) of the barrel 120 . In the embodiment shown, the barrel includes an increased diameter region 125 adjacent to the diameter transition region at the proximal end 129 (as shown in FIG. 3 ) of the barrel. The inner diameter of the barrel 120 at the increased diameter region 125 is greater than the inner diameter of the barrel of the entire diameter transition region 127 .
[0069] The barrel may be made of plastic, glass or other suitable material. The barrel further includes optional dosage measurement indicia (not shown).
[0070] Referring now to FIG. 5 , the stopper 160 has a distal end 161 , a proximal end 169 , a stopper body 164 and a peripheral edge 162 which forms a seal with the interior surface 126 of the barrel. In one or more embodiments, the peripheral edge 162 of the stopper 160 has a larger diameter than the diameter of the interior surface of the rib 123 . The stopper 160 shown in FIG. 5 includes an optional elongate tip 166 on its distal end 161 to facilitate reduction of the residual fluid and expulsion of fluid from the syringe barrel.
[0071] The stopper 160 is shown as further having a tapered portion 165 adjacent to the stopper body 164 at its proximal end 169 . A neck 163 is adjacent to the tapered portion 165 at the proximal end 169 of the stopper 160 . The stopper body 164 is shown as also including an interior recess 168 , which allows the stopper-engaging portion 146 of the plunger rod 140 to connect to the stopper 160 . A peripheral rim 147 may be provided to help retain the stopper 160 on the plunger rod 140 . As with the rib of the barrel, detents or tabs can be used to retain the stopper 160 on the plunger rod 140 .
[0072] The stopper is typically made of plastic or other easily disposable and/or recyclable material. It may be desirable to incorporate natural or synthetic rubber in the stopper or use a natural or synthetic rubber seal with the stopper. It will be understood that the stopper may incorporate multiple seals.
[0073] Referring now to FIG. 6 , the syringe assembly includes a plunger rod 140 having a proximal end 149 , a distal end 141 , and a main body 148 extending between the proximal end 149 and distal end 141 . The plunger rod 140 further includes a thumb press 142 at the proximal end 149 of the plunger rod 140 . In the embodiment shown, the thumb press 142 further includes a textured surface, writeable surface and/or label.
[0074] Still referring to FIG. 6 , the plunger rod 140 further includes a protrusion 144 shown as an annular protrusion 144 between the thumb press 142 and the main body 148 . The outer diameter of the plunger rod at the protrusion 144 is greater than the inner diameter of the barrel 120 at the rib 123 . In some embodiments of the invention, the protrusion 144 includes a tapered portion 145 that facilitates distal movement of the protrusion past the rib 123 and into the barrel 120 , as will become apparent in the subsequent discussion of operation of the syringe. In at least one embodiment, the syringe assembly is configured to allow the protrusion 144 to advance distally past the rib 123 , to lock the plunger rod in the barrel when the user bottoms out the plunger rod in the barrel (as more clearly shown in FIGS. 10-11 ). In certain embodiments, the plunger rod 140 further includes at least one frangible connection or point 143 for separating at least a portion of the plunger rod from the main body when a user applies sufficient proximal force to the plunger rod after it has been locked. In the embodiment shown, the frangible point 143 is located between the protrusion 144 and the thumb press 142 . It will be understood that the frangible connection or point 143 shown is exemplary, and other suitable means for permanently damaging the plunger rod or otherwise separating at least a portion of the plunger rod from the main body may be provided.
[0075] In the embodiment shown, the stopper 160 is permitted to move distally and proximally within the barrel when connected to the stopper-engaging portion 146 of the plunger rod 140 . As will be understood better with the description of operation of the syringe assembly and with reference to FIG. 7 , the stopper is capable of moving distally and proximally a pre-selected axial distance 132 relative to the stopper-engaging portion.
[0076] In alternative embodiments, the stopper is fixed with respect to the plunger rod. In such embodiments, the axial distance may now be zero. It will be appreciated that in such embodiments, the syringe will be in an initial position, as supplied, where there is a gap between the stopper and the distal wall of the barrel. As the user fills the syringe, the stopper and the plunger rod move together in a proximal direction. As the user expels the contents of the syringe, the stopper and the plunger rod move together in the distal direction, the flexible protrusion is permitted to move past the locking rib.
[0077] The plunger rod may be made of plastic or other suitable material. The protrusion may also be comprised of plastic or a harder material suitable for locking the plunger rod within the barrel.
[0078] In FIG. 7 , the barrel 120 holds the stopper 160 and plunger rod 140 in the chamber, wherein the stopper is bottomed, “parked” or is in contact with the distal wall 122 of the barrel 120 . The peripheral edge of the stopper 162 forms a seal with the interior surface 126 of the barrel 120 . In one embodiment, the stopper 160 is connected to the stopper-engaging portion 146 of the plunger rod 140 . The stopper-engaging portion 146 is removeably held in the recess 168 of the stopper body 164 by the neck 163 .
[0079] In FIG. 7 , a gap between stopper 160 and the distal end of the main body 148 defines a pre-selected axial distance 132 prior to the injection cycle. In at least one embodiment, the protrusion 144 remains on the proximal side of the rib 123 because the length of the plunger rod 140 and stopper combined, along with the pre-selected axial distance 132 , is greater than the length of the barrel 120 from the distal wall 122 to the proximal end of the barrel 120 . The distance between the protrusion 144 and the peripheral edge 162 of the stopper body 164 defines a first distance, D 1 .
[0080] FIG. 8 illustrates the syringe assembly in use and specifically shows an aspiration or filling step, according to one or more embodiments of the present invention. When the user applies a force to the plunger rod 140 in the proximal direction shown by the arrow in FIG. 8 , the plunger rod 140 and the stopper 160 move together in the proximal direction, while the stopper-engaging portion 146 is connected to the stopper 160 by the rim 147 . In one or more embodiments, the gap defining the pre-selected axial distance 132 is maintained while the stopper 160 and plunger rod 140 move together in the proximal direction along the interior surface of the syringe barrel. The user terminates the application of proximal force on the plunger rod 140 once the desired amount of medicament is drawn into the syringe. During the aspiration step, the plunger rod and the stopper body move in the proximal direction together to draw medication into the syringe, while maintaining the first distance D 1 .
[0081] FIG. 9 also shows the syringe assembly in use and specifically demonstrates application of distal force to the plunger rod during injection. In one embodiment, when the user applies a force in the distal direction to the plunger rod 140 as indicated by the arrow, the plunger rod 140 moves in a distal direction for the length of the gap defining the pre-selected axial distance 132 in FIG. 7 , while the stopper 160 remains stationary. The stopper 160 remains stationary because the frictional force created by the peripheral edge 162 of the stopper on the interior surface 126 of the barrel is greater than the frictional force created by the stopper-engaging portion 146 entering the recess 168 of the stopper 160 . Consistent with at least one embodiment, once the stopper-engaging portion has distally moved the length of the pre-selected axial distance 132 and is in contact with the proximal end of the recess 169 , the stopper 160 and the plunger rod 140 begin to move in tandem in the distal direction. Further, the force applied by the user is greater than the friction between the peripheral edge 162 of the stopper 160 and the interior surface 126 of the barrel, and therefore the stopper 160 is forced to move in the distal direction with the plunger rod 140 . In one embodiment, the user may inject a limited amount of the fluid aspirated or exert a limited force on the plunger rod in the distal direction to flush or expel some of the aspirated fluid, without locking the plunger rod, provided that the syringe assembly is not bottomed. However, as will be described further with respect to FIG. 10 , a user may bottom the stopper against the distal wall of the syringe barrel, locking the plunger rod in the barrel.
[0082] When expelling the contents of the syringe, the plunger rod moves in a distal direction the length of the pre-selected axial distance 132 shown in FIG. 7 while the stopper body remains stationary, consequently closing the gap defining the pre-selected axial distance 132 . After the contents of the syringe have been fully expelled, the distance between the protrusion 144 and the peripheral edge 162 defines a second distance, D 2 , wherein D 2 is the difference between the first distance, D 1 , and the gap defining a pre-selected axial distance 132 .
[0083] FIG. 10 illustrates an embodiment of the syringe assembly after the plunger rod has been locked inside the barrel. In one or more embodiments, the entry of the stopper-engaging portion into the recess 168 of the stopper 160 (as also shown in FIG. 9 ) closes the gap defining the pre-selected axial distance 132 , allowing the protrusion 144 to advance past the locking rib 123 (as more clearly shown in FIG. 11 ). The protrusion 144 has an outer diameter greater than the inner diameter of the barrel at the rib 123 . Accordingly, in one or more embodiments, the rib 123 locks the protrusion 144 inside the barrel 120 , and prevents proximal movement of the plunger rod 140 .
[0084] FIG. 12 shows a syringe assembly 100 in which the barrel 120 includes a visual marker 300 . The marker is aligned with the rib 123 , as more clearly shown in FIG. 16 . The marker can be integrally formed on the sidewall of the barrel or can be added to the exterior surface of the sidewall. The marker can be printed in ink, adhesively applied, a textured surface or a separate piece that is fixed around the syringe barrel. The marker can form a ring around the circumference of the side wall or be in the form of tabs disposed at regular intervals around the circumference of the side wall. In a specific embodiment, the marker is a colored stripe. In a more specific embodiment, the marker can include text in the form of one or more letters and/or numbers, geometric shapes, symbols or combinations thereof to inform users the syringe is disabled.
[0085] FIG. 13 shows a plunger rod 140 having a visual indicator or display 310 disposed on the stopper-engaging portion 146 . As with the visual marker 300 , the visual indicator 310 can be integrally formed with the stopper-engaging portion of the plunger rod or be added to the exterior surface thereof. The indicator or display can be printed in ink, adhesively applied, a textured surface or a separate piece that is fixed to the stopper engaging portion. In one or more embodiments, the indicator or display can comprise a pattern, a solid portion and or can cover the entire surface of the stopper-engaging portion. In a specific embodiment, the indicator is a colored stripe disposed along the length of the stopper-engaging portion 146 between the distal end 141 and the main body 148 of the plunger rod. In a more specific embodiment, the indicator is a colored stripe disposed along the circumference of the stopper-engaging portion 146 of the plunger rod. In an even more specific embodiment, the marker can include text in the form of one or more letters and/or numbers, geometric shapes, symbols or combinations thereof.
[0086] As more clearly shown in FIG. 14 a gap between stopper 160 and the distal end of the main body 148 defines a pre-selected axial distance 132 prior to the injection cycle. The visual indicator 310 is visible when the gap is present. The visual marker 300 is disposed on the exterior surface of the barrel 120 and aligned with the rib 123 . As described with reference to FIG. 8 , when the user applies a force to the plunger rod 140 in the proximal direction shown by the arrow in FIG. 8 , the plunger rod 140 and the stopper 160 move together in the proximal direction, while the stopper-engaging portion 146 is connected to the stopper 160 by the rim 147 . In one or more embodiments, the gap defining the pre-selected axial distance 132 is maintained while the stopper 160 and plunger rod 140 move together in the proximal direction along the interior surface of the syringe barrel. Accordingly, the visual indicator 310 continues to be visible.
[0087] As described with reference to FIG. 9 , when expelling the contents of the syringe, the plunger rod moves in a distal direction the length of the pre-selected axial distance 132 shown in FIGS. 7 and 14 while the stopper body remains stationary, consequently closing the gap defining the pre-selected axial distance 132 . The movement of the stopper-engaging portion, in the distal direction relative to the stopper allows the stopper-engaging portion 146 of the plunger rod to move into the recess 168 of the stopper (as shown in FIG. 9 ). As can be more clearly seen in FIG. 15 , this relative movement allows the stopper body 164 to cover the stopper-engaging portion and block visibility of the visual indicator 310 .
[0088] As more clearly shown in FIGS. 15 and 16 , the visual marker 300 disposed on the barrel 120 and aligned with the rib 123 also shows advancement of the protrusion 144 past the rib 123 . In addition, the entry of the stopper-engaging portion into the recess 168 of the stopper 160 (as also shown in FIG. 9 ) also closes the gap defining the pre-selected axial distance 132 , allowing the protrusion 144 to advance past the rib 123 (as more clearly shown in FIGS. 11 and 16 ). The location of the protrusion relative to the visual marker indicates whether the plunger rod has been locked within the barrel and the syringe assembly has been disabled. Before the plunger rod is locked, the protrusion 144 is proximally adjacent to the visual marker 300 . Once the plunger rod is locked, the protrusion 144 is distally adjacent to the visual marker 300 .
[0089] It will be appreciated that each of the visual marker 300 and the visual indicator 310 can be used alone or in combination.
[0090] FIG. 17 shows the assembly after the plunger rod 140 has been locked in the barrel 120 . An attempt to reuse the syringe assembly by applying a force to the plunger rod 140 in the proximal direction causes a portion of the plunger rod 140 to separate at the frangible connection or point 143 . The frangible connection or point 143 is designed so that the force holding exerted on the protrusion by the locking rib 123 while proximal force is being applied to the plunger rod 140 is greater than the force needed to break the plunger rod at the frangible point 143 and, therefore, the frangible point breaks or separates before the user is able to overcome the force exerted on the protrusion by the rib.
[0091] FIG. 18 shows the syringe assembly in a configuration in which the stopper 160 has separated from the stopper-engaging portion 146 . According to one or more embodiments of the invention, the stopper 160 and stopper-engaging portion 146 disengage to prevent a user from disassembling the parts of the syringe assembly prior to use. As otherwise described in reference to FIG. 5 , the peripheral edge 162 of the stopper 160 has a diameter greater than the diameter of the interior surface of the rib 123 . Consistent with at least one embodiment of the invention, when a user applies a force to the plunger rod 140 in the proximal direction, the rib 123 locks the peripheral edge 162 of the stopper 160 , and the rim 147 of the stopper-engaging portion 146 disconnects from the neck 163 of the stopper. The rib 123 exerts a greater force on the peripheral edge of the stopper than the force or friction exerted by the rim of the stopper-engaging portion of the plunger rod and neck portion of the stopper while proximal force is applied to the plunger rod.
[0092] FIG. 19 shows an example of a syringe assembly 200 according to another embodiment of the present invention. In the embodiment shown in FIG. 19 , the assembly includes a barrel 220 , a plunger rod 240 and a stopper 260 , arranged so that the proximal end of stopper 269 is attached to the distal end of the plunger rod 241 . The stopper 260 then plunger rod 240 is inserted into the proximal end of the barrel 229 . A flange 224 is attached at the proximal end 229 of the barrel 220 . The barrel 220 further includes a needle cannula 250 having a lumen 253 , attached to the opening in the distal wall 222 at the distal end 221 of the barrel 220 . One or more embodiments also include an attachment hub 252 for attaching the needle cannula 250 to the distal wall 222 . The assembly may also include a protective cap over the needle cannula (not shown).
[0093] Similar to the barrel illustrated previously in FIGS. 3 and 4 , and as shown in FIG. 22 , the barrel further include a rib 223 , locking rib or other means for locking the plunger rod within the barrel, having an interior surface with a smaller diameter than the diameter of the interior surface of the barrel.
[0094] Referring now to FIG. 20 , a perspective view of a plunger rod 240 is shown as having a main body 248 , a distal end 241 and a proximal end 249 . The plunger rod 240 further includes a thumb press 242 at its proximal end and a stopper-engaging portion 246 at its distal end. Plunger rod 240 also includes a protrusion in the form of an annular protrusion 244 between the thumb press 242 and the main body 248 . The protrusion 244 may include a tapered portion 245 to facilitate distal movement of the protrusion 244 past the rib 223 into the barrel 220 . In some embodiments, the protrusion 244 has an outer diameter greater than the inner diameter of the barrel at the rib 223 . In at least one embodiment, the configuration of the syringe assembly allows for the protrusion 244 to advance distally past the rib 223 , to lock the plunger rod 240 in the barrel 220 , when the user bottoms the syringe assembly (as more clearly shown in FIGS. 25-26 and discussed further below).
[0095] The plunger rod 240 shown further includes at least one frangible point 243 . In the embodiment shown, the frangible point 243 of the plunger rod 240 is located between the protrusion 244 and the thumb press 242 , but the frangible point could be in another location. A stopper-engaging portion 246 is included on the distal end 241 of the plunger rod 240 . As shown, the stopper-engaging portion 246 also includes a plunger recess and a retainer 247 . At least one embodiment of the invention includes a press-fit attachment or other suitable means for retaining the end of the stopper.
[0096] Referring now to FIG. 21 , which shows an embodiment of the stopper 260 having a distal end 261 and a proximal end 269 . According to at least one embodiment, the stopper 260 includes a peripheral edge 262 which forms a seal with the interior wall of the barrel 220 and has a diameter greater than the diameter of the interior surface of the barrel at the location of the rib 223 (as more clearly shown in FIGS. 22-24 ). As shown, an elongate tip 266 is provided at the distal end 261 of the stopper 260 to help expel the entire contents of the syringe. The stopper 220 can further include a stopper body 264 having a peripheral lip 263 at its proximal end 269 , according to at least one embodiment of the invention. Further, the stopper 260 can include a stopper frangible connection 265 connecting the stopper body 264 to the stopper 260 .
[0097] In this configuration, the stopper 260 and plunger rod 240 occupy the chamber of the barrel 220 and the stopper is bottomed against the distal wall of the barrel. Further, the peripheral edge 262 of the stopper 260 forms a seal with the interior surface of the barrel 220 . The stopper 260 is connected to the stopper-engaging portion 246 of the plunger rod 240 . As shown, the retainer 247 of the stopper-engaging portion 246 retains the peripheral lip 263 of the stopper 260 .
[0098] Embodiments of the syringe assembly of FIGS. 19-27 can also include a visual marker 300 , visual indicator 310 or both, as described with reference to FIGS. 13-16 . In a specific embodiment, the barrel 220 of one or more embodiments can also include a visual marker aligned with the locking rib 223 . In a more specific embodiment, the syringe assembly can include a visual indicator disposed on the stopper body 264 .
[0099] According to one or more embodiments, there is a gap between the stopper 260 and the distal end of the main body 248 defining a pre-selected axial distance 232 . In one or more embodiments, the distance between the protrusion 244 and the peripheral edge 262 of the stopper 260 defines a first distance, D 1 .
[0100] FIG. 23 illustrates the syringe assembly in use and specifically shows movement of the plunger rod during an aspiration or filling step according to one or more embodiments of the present invention. When the user applies a force to the plunger rod in the proximal direction, the plunger rod 240 and the stopper 260 move together in the proximal direction as indicated by the arrow, while the stopper-engaging portion 246 is connected to the stopper 260 by the rim 263 . In this configuration, the gap defining the pre-selected axial distance 232 is maintained while the stopper 260 and plunger rod 240 move together in the proximal direction. The user applies proximal force to the plunger rod until a predetermined or desired amount of medicament is aspirated or drawn into the syringe. During the aspiration step, the plunger rod and the stopper body move in the proximal direction together to draw medication into the syringe, while maintaining the first distance D 1 .
[0101] FIG. 24 also shows the syringe assembly when distal force is applied to the plunger rod during an injection step according to at least one embodiment of the present invention. Application of a force in the distal direction closing the gap and moving the pre-selected axial distance 232 shown in FIG. 22 , while the stopper 260 remains stationary. Consistent with at least one embodiment, once the stopper-engaging portion 246 has distally moved the pre-selected axial distance 232 and is in contact with stopper frangible connection 265 , the stopper 260 and the plunger rod 240 begin to move in tandem in the distal direction.
[0102] When expelling the contents of the syringe, the plunger rod moves in a distal direction the length of the pre-selected axial distance 232 while the stopper body remains stationary. During and after the contents of the syringe have begun to be or have been fully expelled, the distance between the protrusion 244 and the peripheral edge 262 defines a second distance, D 2 , wherein D 2 is the difference between the first distance, D 1 , and the gap defining a pre-selected axial distance 232 .
[0103] In one embodiment, the user may inject a limited amount of the fluid aspirated or exert a limited force on the plunger rod in the distal direction to flush or expel some of the aspirated fluid, without locking the plunger rod, provided that the syringe assembly is not bottomed. However, as will be described further below, a user will typically expel substantially all of the contents of the syringe by bottoming the stopper on the distal wall of the barrel.
[0104] Referring now to FIG. 25 , which illustrates the syringe assembly after the plunger rod 240 has been locked inside the barrel 220 , the distal movement of the stopper-engaging portion 246 to the stopper frangible connection 265 of the stopper 260 (as also shown in FIG. 24 ) closes the gap defining the pre-selected axial distance and allows the protrusion 244 to advance past the rib 223 , thereby locking the plunger rod 240 inside the barrel 220 , preventing re-use of the syringe assembly
[0105] Referring now to FIG. 26 , the syringe assembly is shown in a configuration in which a user attempts to reuse the syringe assembly after the plunger rod 240 is locked inside the barrel 220 by applying a force to the plunger rod 240 in the proximal direction. Application of sufficient proximal force to the plunger rod causing a portion of the plunger rod 240 to separate at the frangible connection or point 243 , as the holding force of the protrusion 244 and the rib exceeds the breaking force of the frangible point or connection.
[0106] FIG. 27 shows the syringe assembly in a configuration after which proximal force has been applied to the plunger rod and the stopper has moved to the proximal end of the barrel. As shown in FIG. 27 , the stopper 260 has separated from the stopper-engaging portion 246 of the plunger rod. The stopper frangible connection 265 breaks to prevent a user from disassembling the parts of the syringe assembly. As otherwise described herein, the peripheral edge of the stopper 262 has an outer diameter greater than the inner diameter of the interior surface of the barrel at the location of the rib 223 . Consistent with at least one embodiment of the invention, when a user applies a force to the plunger rod 240 in the proximal direction, the rib 223 of the barrel 220 locks the peripheral edge 262 of the stopper 260 , and the stopper frangible connection 265 breaks, separating the stopper body 264 from the stopper 260 . Without being limited by theory, it is believed that the force required to break the stopper frangible connection is less than the force exerted on the peripheral edge of the stopper.
[0107] FIG. 28 shows an example of a syringe assembly 400 according to another embodiment of the present invention. In the embodiment shown in FIG. 28 , the assembly includes a barrel 420 , a plunger rod 440 and a stopper 460 , arranged so that the proximal end of stopper 469 is attached to the distal end of the plunger rod 441 . The stopper 460 then plunger rod 440 is inserted into the proximal end of the barrel 429 . The barrel includes a flange 424 attached at the proximal end 429 of the barrel 420 and a needle cannula 450 having a lumen 453 attached to the opening in the distal wall 422 at the distal end 421 of the barrel 420 . One or more embodiments also include an attachment hub 452 for attaching the needle cannula 450 to the distal wall 442 .
[0108] The barrel as shown more clearly in FIG. 29 further includes a cylindrical sidewall 410 with an inside surface 426 defining a chamber 428 . As more clearly shown in FIG. 30 , the barrel further includes a rib 423 , locking rib or other means for locking the plunger rod within the barrel, having an interior surface with a smaller diameter than the diameter of the interior surface of the barrel. The distal end of the rib 423 further includes a distal portion 412 facing the distal end of the barrel 421 . It will be understood that the rib 423 and the distal portion of the rib 412 can have different shapes and configurations. A ramp 427 is disposed proximally adjacent to the rib 423 having an increasing diameter from the rib to the open proximal end. An increased diameter region 425 is disposed proximally adjacent to the ramp 427 . The increased diameter region 425 may have the same or larger diameter than the inside surface of the barrel 426 .
[0109] Referring now to FIG. 31 , which shows an embodiment of the stopper 460 having a distal end 461 and a proximal end 469 . According to at least one embodiment, the stopper 460 includes a sealing edge 462 which forms a seal with the inside surface of the barrel 426 and has a diameter greater than the diameter of the inside surface of the barrel at the location of the rib 423 (as more clearly shown in FIGS. 29 and 30 ). The stopper 460 can further include a stopper body 464 defining an interior recess 468 and a neck 463 disposed at its proximal end 469 , according to at least one embodiment of the invention. According to one or more embodiments, the stopper may be formed from an elastomeric or plastic material. The stopper may also be formed from other known materials in the art.
[0110] Referring now to FIG. 32 , a perspective view of a plunger rod 440 is shown as having a main body 448 , a distal end 441 and a proximal end 449 . The plunger rod 440 further includes a thumb press 442 at its proximal end and a stopper-engaging portion 446 at its distal end. Plunger rod 440 also includes a flexible protrusion 444 between the thumb press 442 and the main body 448 and a support 445 proximally adjacent to the flexible protrusion, which provides additional stability to the plunger use and syringe 400 during use. In some embodiments, the flexible protrusion 444 has an outer diameter greater than the inner diameter of the barrel at the rib 423 . In at least one embodiment, the configuration of the syringe assembly allows for the flexible protrusion 444 to advance distally past the rib 423 , to lock the plunger rod 440 in the barrel 420 , when the user bottoms the syringe assembly (as more clearly shown in FIGS. 37-38 and discussed further below). The plunger rod may further include an optional pair of discs 430 , 431 disposed on the distal end and proximal end of the main body 448 . The discs 430 , 431 provide additional stability and may have alternate shapes, depending on the shape of the barrel.
[0111] As shown in FIG. 33 , the plunger rod 440 further includes a plurality of frangible connections or bridges 443 adjacent to the support 445 . In the embodiment shown, the plurality of frangible connections 443 of the plunger rod 440 is located between the support 445 and the thumb press 442 , but the frangible connections could be in another location.
[0112] The distal end of the plunger rod 441 further includes a stopper-engaging portion 446 . As shown, the stopper-engaging portion 446 also includes a retaining ring 447 for retaining the neck 463 of the stopper 460 . At least one embodiment of the invention includes a press-fit attachment or other suitable means for retaining the end of the stopper.
[0113] When assembled, the stopper 460 is connected to the stopper-engaging portion 446 of the plunger rod 440 . In the embodiment shown in FIG. 34 , the stopper 460 and plunger rod 440 may occupy the chamber of the barrel 420 with the distal end 461 of the stopper face positioned against the distal wall of the barrel 422 . Further, the sealing edge 462 of the stopper 460 forms a seal with the interior surface of the barrel 420 . As shown, the retaining ring 447 of the stopper-engaging portion 446 retains the stopper 460 . As will be more fully described with reference to FIG. 40 , the connection between the retaining ring 447 and stopper-engaging portion 446 may be frangible.
[0114] Embodiments of the syringe assembly 400 may also include visual markers as described with reference to FIGS. 13-16 . In a specific embodiment, the barrel 420 of one or more embodiments can also include a visual marker aligned with the locking rib 423 . In a more specific embodiment, the syringe assembly can include a visual indicator disposed on the stopper body 464 .
[0115] Referring now to FIGS. 34-35 , a defined space between the stopper 460 and the distal end of the main body 448 defining a pre-selected axial distance 432 . In one or more embodiments, the distance between the flexible protrusion 444 and the sealing edge 462 of the stopper 460 defines a first distance, D 1 .
[0116] The aspiration or filling step, the injection step and the locking step is shown in FIGS. 35-38 . As with the embodiments of FIGS. 7-11 , 14 - 16 and 22 - 24 , when the user applies a force to the plunger rod in the proximal direction, the plunger rod 440 and the stopper 460 , joined by the neck 463 and retaining ring 447 , move together in the proximal direction as indicated by the arrow. As shown in FIG. 35 , the space defining the pre-selected axial distance 432 and the first distance D 1 is maintained as the stopper 460 and plunger rod 440 move together in the proximal direction. FIG. 36 shows the syringe assembly 400 when distal force is applied to the plunger rod 440 during an injection step. This force causes the plunger rod 440 to move the pre-selected axial distance 432 shown in FIG. 34 while the stopper 460 remains stationary. This closes the space between the plunger rod 440 and stopper 460 as the plunger rod 440 moves into the interior recess 468 . Application of a continuous force in the distal direction to the plunger rod causes the stopper 460 and the plunger rod 440 to move in tandem in the distal direction.
[0117] During and after the contents of the syringe have begun to be or have been fully expelled, the distance between the flexible protrusion 444 and the sealing edge 462 defines a second distance, D 2 , wherein D 2 is the difference between the first distance, D 1 , and the space defining a pre-selected axial distance 432 .
[0118] As described otherwise herein, the user of the syringe assembly 400 may inject a limited amount of the fluid aspirated or exert a limited force on the plunger rod in the distal direction to flush or expel some of the aspirated fluid, without locking the plunger rod, provided that the syringe assembly is not bottomed.
[0119] Referring now to FIGS. 37-38 , which illustrate the syringe assembly after the plunger rod 440 has been locked inside the barrel 420 , the distal movement of the stopper-engaging portion 446 relative to the stopper 460 closes the gap defining the pre-selected axial distance and allows the flexible protrusion 444 to advance past the rib 423 , thereby locking the plunger rod 440 inside the barrel 420 , preventing re-use of the syringe assembly.
[0120] According to one or more embodiments, the flexible protrusion 444 permits the plunger rod to bottom during normal use of the syringe assembly. Specifically, the flexible protrusion 444 flexes as it moves past the narrowed diameter of the rib 423 of the barrel. In one or more embodiments, as the protrusion 444 moves distally past the rib 423 , a slight increase in force may be applied to the plunger rod. According to the embodiment shown, this slight increase in force applied to the plunger rod is not perceptible to a user during normal use of the syringe. Further, the ramp 427 of the barrel facilitates movement of the flexible protrusion 444 past the rib 423 . After the flexible protrusion 444 has advanced distally past the rib 423 , the distal portion of the rib 412 restricts movement of the flexible protrusion 444 in the proximal direction. It is believed that the activation force, as defined herein, is less than the force required to withdraw the plunger rod.
[0121] Referring now to FIG. 39 , the syringe assembly 400 is shown in a configuration in which a user attempts to reuse the syringe assembly after the plunger rod 440 is locked inside the barrel 420 by applying a withdrawal force, as defined herein, to the plunger rod 440 in the proximal direction. Application of sufficient proximal force to the plunger rod causing a portion of the plunger rod 440 to separate at the plurality of frangible connections 443 , as the withdrawal force exceeds the deactivation force needed to separate a portion of the plunger rod from the body or break the plurality of frangible connections or bridges.
[0122] FIG. 40 shows the syringe assembly 400 in a configuration after which proximal force has been applied to the plunger rod and the stopper has moved to the proximal end of the barrel. As otherwise described herein, the sealing edge of the stopper 462 has an outer diameter greater than the inner diameter of the interior surface of the barrel at the location of the rib 423 and therefore, application of a force in the force in the proximal direction causes the stopper 460 to separated from the stopper-engaging portion 446 of the plunger rod
[0123] According to one or more embodiments, the syringe barrel may include identifying information on the syringe assembly. Such information can include, but is not limited to one or more of identifying information regarding the contents of the syringe assembly or information regarding the intended recipient.
[0124] Reference throughout this specification to “one embodiment,” “certain embodiments,” “one or more embodiments” or “an embodiment” means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases such as “in one or more embodiments,” “in certain embodiments,” “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.
[0125] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the method and apparatus of the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention include modifications and variations that are within the scope of the appended claims and their equivalents. | Syringe assemblies having a passive disabling system to prevent reuse are provided. According to one or more embodiments, the syringe assembly comprises a barrel, plunger rod and stopper wherein the plunger rod further comprises a flexible protrusion that locks the plunger rod within the barrel. Certain embodiments further include a frangible portion on the plunger rod that breaks when reuse is attempted. One or more embodiments include a plunger rod and stopper attachment that prevents disassembly of the syringe assembly prior to use. Syringe assemblies of one or more embodiments also include visual indicators or markers indicating whether a syringe assembly is used or the plunger rod is locked within the barrel. | 0 |
TECHNICAL FIELD
[0001] The present invention relates to an illumination system for an imaging reader and, more particularly, to an illumination system for an imaging reader including smart illumination that provides a visually defined and prescribed field-of-view in a direction toward a target object for imaging.
BACKGROUND
[0002] Various electro-optical systems have been developed for reading optical indicia, such as bar codes. A bar code is a coded pattern of graphical indicia comprised of a series of bars and spaces of varying widths, the bars and spaces having differing light reflecting characteristics. Some of the more popular bar code symbologies include: Uniform Product Code (UPC), typically used in retail stores sales; Code 39, primarily used in inventory tracking; and Postnet, which is used for encoding zip codes for U.S. mail. Systems that read and decode bar codes employing charged coupled device (CCD) or complementary metal oxide semiconductor (CMOS) based imaging systems are typically referred to hereinafter as imaging systems, imaging-based bar code readers, imaging readers, or bar code scanners.
[0003] Imaging systems electro-optically transform the graphic indicia into electrical signals, which are decoded into alphanumerical characters that are intended to be descriptive of the article or some characteristic thereof. The characters are then typically represented in digital form and utilized as an input to a data processing system for various end-user applications such as point-of-sale processing, inventory control, and the like.
[0004] Imaging-based bar code reader systems that include CCD, CMOS, or other imaging configurations comprise a plurality of photosensitive elements (photosensors) or pixels typically aligned in an array pattern that could include a number of arrays. The imaging-based bar code reader systems employ light emitting diodes (LEDs) or other light sources for illuminating a target object, e.g., a target bar code. Light reflected from the target bar code is focused through a lens of the imaging system onto the pixel array. As a result, the focusing lens generates an image from its field-of-view (FOV) that is projected onto the pixel array. Periodically, the pixels of the array are sequentially read out, creating an analog signal representative of a captured image frame. The analog signal is amplified by a gain factor, by for example an operational amplifier or microprocessor. The amplified analog signal is digitized by an analog-to-digital converter. Decoding circuitry of the imaging system processes the digitized signals representative of the captured image frame and attempts to decode the imaged bar code.
SUMMARY
[0005] One example embodiment of the present disclosure includes an imaging assembly capable of reading a target object comprising a scan engine having a sensor, focusing optics, and an imager. The scan engine includes a field-of-view that defines an area to be imaged by the imaging assembly. A housing internally lodges the scan engine and an illumination source. The illumination source is adapted to project illumination from the housing. A boot extends from the housing for shaping the illumination as it passes through the boot to form an illumination pattern from the illumination. The illumination pattern substantially conforms to a geometrical shape of the boot and is adapted to envelope the scan engine field-of-view.
[0006] Another example embodiment of the present disclosure includes a method of imaging a target object comprising projecting a field-of-view from a scan engine located in a housing of an imaging assembly and projecting illumination from an illumination source located within the housing to a location outside of the housing by passing the illumination through a boot extending from the housing. The method further comprises shaping the illumination from the illumination source to form an illumination pattern as it passes through the boot. The illumination pattern has a substantially similar shape as the boot. The illumination pattern further envelops the field-of-view such that the illumination pattern is at a fixed offset location relative to the field-of-view.
[0007] A further example embodiment of the present disclosure includes a method of imaging a target object comprising projecting an imaging field-of-view from a scan engine located in a housing of an imaging assembly and projecting illumination from an illumination means located within the housing to a location outside of the housing by passing the illumination through a baffling means extending from the housing. The method further comprises shaping the illumination from the illumination means by redirecting and diffusing at least a portion of the light projected from the illumination means to form an illumination pattern as it passes through the baffling means. The illumination pattern has a substantially similar shape as the baffling means. The illumination pattern further envelops the field-of-view such that the illumination pattern is at a fixed offset location relative to the field-of-view.
[0008] Yet a further example embodiment of the present disclosure includes a hand-held image scanner used for reading target objects comprising a scan engine having a sensor and imager. The scan engine has a field-of-view defining an area to be imaged by the image scanner. The hand-held image scanner further comprises a housing internally lodging the scan engine and an illumination source. The illumination source is adapted to project illumination from the housing. A boot extends from the housing for shaping an illumination pattern from the illumination as it passes through the boot. The illumination pattern forms a fixed envelop distance about at least a portion of the perimeter of the scan engine field-of-view.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing and other features and advantages of the present invention will become apparent to one skilled in the art to which the present invention relates upon consideration of the following description of the invention with reference to the accompanying drawings, in which:
[0010] FIG. 1 is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure;
[0011] FIG. 2 is a top view of the imaging reader of FIG. 1 ;
[0012] FIG. 3 is a side view of the imaging reader of FIG. 1 ;
[0013] FIG. 4 is an elevated front view of the imaging reader of FIG. 1 ;
[0014] FIG. 5A is a side view of the imaging reader of FIG. 1 reading a target object located on a package;
[0015] FIG. 5B is a partial-sectional view of an imaging reader and boot, illustrating an imaging field-of-view and smart illumination projected on a target object;
[0016] FIG. 6 is an image of a smart illumination pattern projected by the imaging reader in FIG. 5A ;
[0017] FIG. 7 is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure;
[0018] FIG. 8 is a perspective view of an object being scanned by the imaging reader of FIG. 7 ;
[0019] FIG. 9 is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure;
[0020] FIG. 10 is an image of a smart illumination pattern projected by the imaging reader in FIG. 9 ;
[0021] FIG. 11 is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure;
[0022] FIG. 12 is an image of a smart illumination pattern projected by the imaging reader in FIG. 11 ;
[0023] FIG. 13 is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure;
[0024] FIG. 14 is an image of a smart illumination pattern projected by the imaging reader in FIG. 13 ;
[0025] FIG. 15 is a perspective view of one example embodiment of a boot attached to an imaging reader;
[0026] FIG. 16 is a perspective view of one example embodiment of a boot attached to an imaging reader;
[0027] FIG. 17 is a perspective view of one example embodiment of a boot attached to an imaging reader;
[0028] FIG. 18 is a sectional view of the imaging reader of FIG. 3 along section lines 18 - 18 ;
[0029] FIG. 19 is a sectional view of the imaging reader of FIG. 2 along section lines 19 - 19 ; and
[0030] FIG. 20 is block diagram illustrating an imaging process using smart illumination in an imaging reader.
DETAILED DESCRIPTION
[0031] An elevated perspective view of an imaging reader 10 is depicted in FIG. 1 . The imaging reader 10 is a portable scanner in the illustrated embodiment of FIG. 1 , employing an internal power source such as a battery, but could just as easily be a reader having a wire connection from which power is supplied, or remotely powered through an induction system without departing from the spirit and scope of the claimed invention. In addition to imaging and decoding 1D and 2D bar codes, including for example postal codes, and Code 39 bar codes, the reader 10 is also capable of capturing images and signatures. In one example embodiment, the imaging reader 10 is a hand held portable scanner that can be carried and used by a user walking or riding through a store, warehouse, or plant, while reading various symbology codes for stocking and inventory control purposes. However, it should be recognized that the imaging reader 10 of the present invention, to be explained below, may be advantageously used in connection with any type of imaging-based automatic identification system including, but not limited to, bar code scanners, signature imaging acquisition and identification systems, optical character recognition systems, fingerprint identification systems, and the like. It is the intent of the present invention to encompass all such imaging-based automatic identification systems.
[0032] Referring now to FIGS. 1-4 , the imaging reader 10 includes a handle 12 , which is located between an upper end 14 and lower end 16 of the reader 10 . The reader 10 further includes a head 18 situated between first and second ends 20 and 22 , respectively. Extending from and connected to the reader head 18 is a boot 30 . The boot 30 , as discussed further in detail below, provides visually defined fixed and prescribed illumination pattern in a direction toward a target object 32 , such as a bar code for imaging, as illustrated in FIG. 5A . The target object 32 in FIG. 5A is located on a package 34 and in addition to being any indicia form of symbology, the target object could also be located on any type of product or packaging.
[0033] An imager field-of-view FOV is projected from the imaging reader 10 as best seen in FIG. 5A and in the partial sectional view of the imaging reader in FIG. 5B . The imager FOV is the extent of the area imaged by the reader 10 and identified as area A in FIGS. 5A and 5B . In the illustrated embodiment of FIGS. 5A and 5B , the imager FOV extends beyond the outer limits Z 1 and Z 2 of the target object 32 , however it could also reside within the outer limits Z 1 and Z 2 for certain symbology types and still successfully image the target object 32 .
[0034] An illumination source 36 is located in the imaging reader 10 and in combination with the boot 30 , projects smart illumination illustrated as an illumination pattern 38 identified by the area B in FIGS. 5A and 5B . In the illustrated embodiment, the imaging process is manually initiated by a trigger 40 located on the handle 12 of the imaging reader 10 . When the trigger 40 is engaged, it enables the illumination from the illumination source 36 that is shaped by the boot 30 to form the illumination pattern 38 . An operator when using the imaging reader 10 , projects the illumination pattern 38 upon the target object 32 . Automated image reader systems can also be used without departing from the spirit and scope of the claimed invention, which are initiated by an instruction internal to the reading system's software or circuitry. Alternatively, the initiation of the automatic reading system may be continuous once power is supplied to the reader. For either the manual or automatic reading systems, the illumination source 36 is energized, projecting the illumination through the boot 30 that shapes the illumination pattern 38 projected from the imaging reader 10 .
[0035] The illumination pattern 38 is a prescribed pattern defined by the geometry of the boot 30 . The illumination pattern 38 comprises an envelop distance located just beyond the imager FOV. In the illustrated example of FIG. 5B , the imager FOV is at an angle θ A about an optical axis OA of the imaging reader 10 . The illumination pattern 38 defined by the boot 30 provides a fixed angle θ B about the optical axis OA. The boot 30 truncates light that would normally pass from the reader absent the boot and reallocates light into the illumination pattern 38 such that
[0000] =θ B −θ A
[0000] for all illumination patterns 38 relative to the imager FOV about the optical axis OA.
[0036] The illumination source 36 can be a single light emitting diode (LED), bank of LEDs, LEDs projecting light through a lens, a cold cathode lamp (CFL), or an LED projecting light through one or more light pipes 42 as illustrated in FIGS. 18 and 19 . FIGS. 18 and 19 are sectional views of the imaging reader 10 for FIGS. 3 and 2 , respectively.
[0037] Once the illumination pattern 38 is defined by the boot 30 and projected from the imaging reader 10 , an image from the target object 32 is reflected back toward the imager into focusing optics 44 that includes a single or plurality of lenses. The focusing optics 44 then focuses the reflected image onto an imaging sensor 46 , such as a multi-dimensional pixel array, filling the pixel array with data. The imaging sensor 46 is coupled to an imager positioned on a printed circuit board 48 (PCB). The imaging sensor produces a data grid corresponding to the reflected image from the target object 32 . It should be appreciated by those skilled in the art that the imaging sensor 46 such as a pixel array and imager could be either a charged coupled device (CCD) or complementary metal oxide semiconductor (CMOS) based imaging type array, both having multi-dimensional array of sensors that sense the reflected image and form pixel data corresponding to the image of the target object 32 .
[0038] An analog to digital (“A/D”) converter is located on the PCB 48 receives the stored analog image from the imager. The A/D converter then sends a digital signal to a decoder located either on the PCB 48 or remotely from the imaging reader 10 . The signal is then synthesized by the decoder's internal circuitry. The PCB 48 may further include a microprocessor that assists in processing and decoding the image into a data stream through software or firmware. The firmware and/or software includes computer readable media embedded within the microprocessor onto for example, flash Read Only Memory (ROMs) or as a binary image file that can be programmed by a user. Alternatively, the PCB could include an application specific integrated circuit (ASIC).
[0039] If the decode process executed within the decoder is successful, the decode session may be terminated with the decoded information being transmitted to an output of the PCB 48 , which could be tied to a number of reader peripherals. The periperherals include for example, visual display devices such as a monitor or LED, a speaker, or the like. The imaging reader 10 could further include a laser diode 50 that assists by projecting an aiming pattern onto the target object 32 . Further, a bezel diffuser 52 is illustrated in FIGS. 18 and 19 that assists in scattering the light from the illumination source 36 .
[0040] The sectional views of FIGS. 18 and 19 further illustrate the truncating and reallocating of the illumination in the illumination pattern 38 shaped by the boot 30 . In particular, it can be seen that the boot 30 clips or truncates the light beams 60 emitted from the light pipes 42 and instead, redirects the beams to be concentrated within the illumination pattern 38 . For example, redirected light beams 62 are diffused within the boot 30 and projected upon the target object 32 within the illumination pattern 38 . Accordingly, the illumination pattern 38 can assist the user in directing the gun toward the target object 32 .
[0041] The boot 30 is made from any type of reflective or diffuse material. In the illustrated embodiments, the boot 30 is made from diffuse white plastic, such as thermoplastic TEXAN® 950 manufactured by Bayer MaterialScience LLC, of Pittsburg, Pa. The geometry of the boot 30 is reflected in the shape of the illumination pattern 38 , producing a sharp light intensity boundary in which illumination is significantly reduced outside the boundary of the illumination pattern. Stated another way, the illumination pattern 38 can be shaped to reflect a desired geometry based on the configuration of the boot 30 . For example, the oval-shaped boot 30 in FIG. 5A provides an oval-shaped illumination pattern 38 illustrated in FIG. 6 , the round-shaped boot 30 in FIG. 9 provides round-shaped illumination pattern 38 illustrated in FIG. 10 , the rectangular-shaped boot 30 in FIG. 11 provides a rectangular-shaped illumination pattern 38 illustrated in FIG. 12 , and the boot 30 in FIG. 13 comprising left and right sides projects a sharp left and right contrast in the illumination pattern 38 of FIG. 14 .
[0042] In addition to shaping the illumination pattern 38 , the boot 30 can be used to position a package or object during imaging, as illustrated in FIGS. 7 and 8 . The boot 30 in the illustrated embodiment of FIGS. 7 and 8 includes a plurality of slots 70 for guiding and supporting an object 72 during imaging, such as a tube. Further, the boot 30 could include an upper recess 74 illustrated in FIGS. 1-4 to allow the user of a handheld image reader 10 in close proximity scans to see over the reader and view the target object 32 and/or illumination pattern 38 . A corresponding lower recess 74 ′ is provided symmetrically about the OA so that the illumination pattern 38 is uniform along its upper and lower profiles. The illustrated embodiment of FIG. 13 provides additional viewing clearance for the user by constructing the boot 30 to have only left and right sides.
[0043] Referring again to FIGS. 18 and 19 , the imaging reader 10 includes a housing 80 surrounded by overmolded rubber 82 . The boot 30 can be integrally connected to the housing 80 , or be detachably connected so that different sizes can be used to accommodate different imager FOVs and imaging applications. For example, FIGS. 15-17 illustrate three different example embodiments of a detachable boot 30 . In FIG. 15 , the boot 30 comprises a plurality of slots 84 about its perimeters that engage a corresponding boss (not shown) located in the housing 80 of the imaging reader 10 . The slots allow for the amount of extension of the boot 30 beyond the head 18 .
[0044] In an alternative example embodiment illustrated in FIG. 16 , the boot 30 includes a plurality of apertures 86 that can be selected for adjusting the depth by engaging at least one aperture with a corresponding boss (not shown) located within the housing 80 of the imaging reader 10 . Further, the multiple apertures 86 can be used to engage more than one corresponding boss to facilitate additional support and an anti-rotation connection. In yet another alternative example embodiment illustrated in FIG. 17 , the boot 30 includes a number of bosses 88 where at least one is selectively received by a corresponding recess (not shown) in the housing 80 , allowing adjustment to the amount of extension of the boot beyond the head 18 .
[0045] FIG. 20 illustrates a process 100 for using and adjusting an imaging reader 10 having a boot 30 for projecting an illumination pattern 38 . The amount of adjustment of the boot is along the distance X illustrated in FIG. 5B . At 102 , the imager FOV is determined. At 104 , the imaging reader is enabled. At 106 , a determination is made on whether the illumination pattern enveloped the imager FOV. If the determination at 106 is an affirmative, the process ends at 108 . If the determination at 106 is negative, a determination is made at 110 . The determination at 110 is whether the illumination pattern extends outside the imager FOV. If the determination at 110 is an affirmative, a determination is made at 112 . The determination at 112 is whether the illumination pattern extends too far outside the imager FOV. If the determination at 112 is an affirmative, the length of the boot should be increased at 114 and the process is repeated at step 106 . If the determination at 112 is negative, the process is repeated as at step 106 . If the determination at 110 is negative, the length of the boot should be decreased at 116 and the process is repeated at step 106 .
[0046] What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims. | A method and imaging assembly ( 10 ) are disclosed adapted for reading a target object comprising a scan engine ( 48 ) having a sensor ( 46 ), focusing optics ( 44 ), and an imager ( 48 ). The scan engine includes a field-of-view defining an area to be imaged by the imaging assembly ( 10 ). A housing ( 80 ) internally lodges the scan engine ( 48 ) and an illumination source ( 36 ). The illumination source ( 36 ) is adapted to project illumination from the housing ( 80 ). A boot ( 30 ) extends from the housing ( 80 ) for shaping the illumination as it passes through the boot to form an illumination pattern from the illumination. The illumination pattern substantially conforms to a geometrical shape of the boot ( 30 ) and is adapted to envelope the scan engine field-of-view. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The handle of the present invention is useful with the panoramic camera shown in applicant's pending patent application, Ser. No. 243,517, filed Sept. 12, 1988, U.S. Pat. No. 4,864,335.
BACKGROUND OF THE INVENTION
The field of the invention is photography, and the invention relates more particularly to panoramic cameras of the type useful for taking a picture while being rotated. One such camera is shown in applicant's co-pending patent application, Serial No. 243,517, filed Sept. 12, 1988. Such application discloses a handle which has a shaft connectable to the camera, which shaft is operated by a battery-driven motor. Such handle is useful for many applications, but has the inherent shortcomings of any battery-operated device, namely, the imperfect movement when the battery is about dissipated.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a manually operated handle for panoramic cameras.
The present invention is for a manually operated handle for panoramic cameras comprising a handle body having a central opening, which body has a vertical axis. A rotatable, central shaft is held by the handle body, and the axis of the shaft is parallel to the vertical axis of the handle body. An upper portion of the shaft is affixable to a panoramic camera, and the central shaft also has a lower portion. Gear means are affixed to the lower portion of the central shaft and a first one-way clutch contacts the lower portion of the central shaft and is located between the gear means and the upper portion of the central shaft. This first one-way clutch permits the gear means to turn in a first direction to turn the upper portion of the central shaft and to turn in a direction opposite to the first direction freely without turning the upper portion of the central shaft. Rack means are slidably held by the handle body, and the rack means have teeth which mesh with the gear means. The rack means is mounted at a right angle with respect to the central axis of the central shaft. A second one-way clutch is held by the handle body and contacts the upper portion of the central shaft and permits it to turn only in a first direction. The rack may be moved by a trigger affixed thereto or by the turning of a worn gear rotatably held by the rack assembly. When a worm gear is used, preferalby a slidable nut may be moved in and out of contact with the worm gear to permit the resetting of the rack.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the manually operated handle of the present invention showing a panoramic camera in phantom view.
FIG. 2 is an enlarged perspective view of the manually operated handle of FIG. 1.
FIG. 3 is an enlarged cross-sectional view taken along line 3--3 of FIG. 2.
FIG. 4 is an enlarged cross-sectional view of the worm gear and slidably nut of the panoramic camera of FIG. 1.
FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 3.
FIG. 6 is a perspective view of an alternate embodiment of the manually operated handle assembly of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The manually operated handle assembly of the present invention is shown in perspective view in FIG. 1 and indicated by reference character 10. A panoramic camera 1 is shown in phantom view and is of the type described in applicant's co-pending application referencee above. The camera 11 is held to the shaft by a thumb screw 12 threaded into platform 23. Thumb screw 12 is shown in FIG. 3 and abuts a flat 13 in the upper portion 14 of shaft 15. A drive belt 16 passes over a handle pulley 17 which is affixed by a thumb screw 18 to a collar 19. Collar 19 is held by disk 24 which, in turn, is held by screws 25 onto handle body 21. Collar 19 contains a one-way clutch 20 between the handle body 21 and the upper portion 14 of shaft 15. It is important that the camera 11 not be permitted to rotate in a reverse direction but only in a forward direction. The turning of camera 11 in a reverse direction could re-expose a portion of the already exposed film. Handle body 21 includes a threaded opening 46 for attachment of a tripod in a conventional manner.
Shaft 15 has a central axis 22 about which it rotates. Shaft 15 has a lower portion 26 which has the same central axis 22 as the upper portion 14. A set screw 27 holds the upper portion 14 to the lower portion 26. A gear 28 contacts the lower portion 26 of shaft 15 through a one-way clutch 29. One-way clutch 29 permits gear 28 to rotate shaft 15 when it is turned in a first direction, but to turn freely with respect to shaft 15 when it is rotated in a direction opposite to the first direction. It should be noted that although one-way clutch 29 is shown between gear 28 and the lower portion 26 of shaft 15, it could, instead, be positioned between lower portion 26 and upper portion 14.
A rack 30 is slidably held in a generally rectangular opening 31. Rack 30 has a plurality of teeth 32 which cause gear 28 to turn as rack 30 slides along the generally rectangular opening 31. A worn gear 33 is mounted on rack 30 by a bearing 34 affixed to worm gear 33 at one end, and a bearing 35 affixed at the handle end. A handle 36 has a knob 37 which facilitates the turning of worn gear 33. A slidable nut 38, shown best in FIG. 4, may be moved into contact (as shown in FIG. 3) or out of contact (as shown in FIG. 4) with worm gear 33. Slidable nut 38 has a slot 39 which allows it to be slidably held to handle body 21 by screw 40. A knob 41 may be turned to move slidable nut 38 up and down by way of a cam 42 held on a central shaft 43 which, in turn, is held by handle body 21 as shown best in FIG. 3. Cam 42 contacts a cam follower 44 which comprises an opening in slidable nut 38.
In operation, the slidable nut 38 is moved to a downward position, as shown in FIG. 4, and rack 30 is moved in the direction of handle 36. One-way clutch 29 permits gear 28 to turn freely with respect to lower portion 26 of shaft 15. Next, knob 41 is turned to move slidable nut 38 at the contact with worm gear 33. Camera 11 is then set to take a panoramic picture, and knob 37 is turned, thereby turning worm gear 33 which, because it is contacting nut 38, moves rack 30 with respect to handle body 21. This causes gear 28 to turn shaft 15. One-way clutch 20 permits the turning of shaft 15 in this direction, and the picture is obtained. When another picture is desired, knob 41 is again turned to move slidable nut 38 out of contact with worm gear 33. Slidable nut 38 subtends less than 180° around worm gear 33.
A simpler configuration is shown in FIG. 6 where rack 30 does not support a worm gear but, instead, has only a trigger 45 which can be manually squeezed toward handle body 21 causing the shaft 15 to turn as described below. It is, of course, also possible to combine the two configurations and to include a trigger 45 adjacent handle 36 so that it may be operated either through worm gear 33 or directly by trigger 45.
The manually operated handle of the present invention provides an exceptionally reliable method of turning a panoramic camera. It does not rely upon a battery or motor or switch but, instead, is always ready for use even in temperature extremes.
The present embodiments of this invention are thus to be considered in all respects as illustrative and not restrictive; the scope of the invention being indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein. | A manually operated handle for panoramic cameras. The handle has a shaft which extends upwardly for contact with a panoramic camera. The shaft is caused to rotate by the moving of a rack along the side of the handle. A pair of one-way clutches causes the shaft to move only in one direction. | 5 |
RELATED APPLICATIONS
The present disclosure relates to the subject matter disclosed in German applications No. 101 10 736.6 of Mar. 1, 2001 and No. 101 54 655.6 of Oct. 31, 2001, which are incorporated herein by reference in their entirety and for all purposes.
FIELD OF THE INVENTION
The invention relates to a reproduction method for printing in which characteristic data of an original are transformed into data required for printing.
BACKGROUND OF THE INVENTION
In reproduction methods for printing a color proof is usually made, for example, from a slide using corresponding color filters. The color space associated with a scanner is an RGB color space with the process colors red (R), green (G) and blue (B). During the printing, for example, offset printing, the color proofs are screened. The color impression in offset printing is based on autotypical color synthesis, i.e., on a combination of additive color synthesis and subtractive color synthesis. The process color space of the printing inks is usually a CMYK color space in which the process colors are cyan (C), magenta (M), yellow (Y) and black (K).
The resulting print should naturally be as close as possible to the original, i.e., the quality and color fidelity of the image reproduction in the print should be as high as possible.
During the printing itself, a specific problem occurs in that mechanical influences cause ink dots to be squeezed, for example, in offset printing during transfer from the offset plate to the rubber blanket and then again during transfer from the rubber blanket to paper. A printed screen dot is then enlarged during the printing operation, i.e., it has a larger dot area than was actually provided for by the transformation from the original to the data required for printing. In principle, dot gain is an undesired and annoying effect which may affect the color reproduction in the print. The effect of dot gain may result in color distortions in the print in comparison with the original.
The effect of dot gain is indicated by a so-called characteristic curve of printing (printing characteristics) in which the area coverage in the print is shown with respect to the area coverage in an original with a colored application, for example, a film or a plate. Without dot gain, the characteristic curve of printing would be a straight line which represents a line bisecting the angle between ordinate (area coverage in the print) and abscissa (area coverage in the original with a colored application).
In the publication “PHILOSOPHIE DES COLOR MANAGEMENT; Postscriptum Color Management” by S. Brües, L. May and D. Fuchs, LOGO GmbH, 2 nd edition, February 2000, reproduction processes are described against the background of color management.
The object underlying the invention is to provide a reproduction method for printing in which the dot gain is controllable so as to obtain optimum reproduction results in the print.
SUMMARY OF THE INVENTION
This object is accomplished in accordance with the invention in that a modified characteristic curve of printing which in relation to the ideal characteristic curve of printing has a maximum above an area coverage of 50% is predefined for the transformation of the data in order to control the dot gain in printing.
The modified characteristic curve of printing can be represented by plotting the dot gain (in percent) against the area coverage in percent of the plate or film.
In this representation the abscissa (the 0% line of the dot gain) is the ideal characteristic curve of printing.
In accordance with the invention, a modified characteristic curve of printing or a modified dot gain is predefined, which is not based on experimental values, but is theoretically predefined. To date, it is common practice to determine experimental printing characteristics and to then take these into account in the transformation. However, the actual printing characteristics (characteristic curve of printing) differ from printing machine to printing machine and are dependent upon the quality of the printing inks used and also upon the type of paper on which the printing is done. The determining of the printing characteristics (characteristic curve of printing) in each case involves considerable expenditure.
In accordance with the invention provision is made for the maximum of the modified characteristic curve of printing in relation to the ideal characteristic curve of printing to lie above an area coverage of 50% and, in particular, to lie at an area coverage of between 50% and 70%. Very good results have been obtained when the maximum of the modified characteristic curve of printing in relation to the ideal characteristic curve of printing lies at approximately 60% area coverage. These good results are, above all, due to the fact that in modern reproduction processes screen dots do not have a square cross section but are, for example, substantially circular. This is also the reason why in the printing of all screen dots of a screen, there is not total area coverage, i.e., there is not 100% area coverage. The maximum should lie in a range where neighboring screen dots start to overlap. This is the case when an area coverage of more than 50% is reached.
Theoretically, circular dots on an area on which they are arranged like a checkerboard start to overlap at an area coverage of approximately 78% (π/4 ·100%). If a dot gain of approximately 10% to 25% is also taken into account the maximum should then lie at approximately 60% area coverage.
As theoretical ansatz for the characteristic curve of printing, a zero crossing may lie at a finite value of the area coverage, i.e., in particular, outside an area coverage of 0% and/or an area coverage of 100%. The modified characteristic curve of printing in the range of low area coverages from zero area coverage to the corresponding zero crossing thus corresponds to the ideal characteristic curve of printing and alternatively or additionally in the range of high area coverages from the zero crossing to 100% area coverage to the ideal characteristic curve of printing. In particular, this ansatz is based on the observation that at low area coverages a higher color fidelity is achieved when the modified dot gain is not set too high. This is due to the fact that in the case of small area coverages, the printed dots are small and so the dot gain is presumably of less importance. An unsuitable compensation attempt can then cause much stronger color deviations than the renunciation of compensation in accordance with the invention or a reduction in the compensation in the case of very small area coverages. In the case of very small area coverages (less than 3%) it is also very difficult to print dots from a mechanical viewpoint insofar as the printing is performed with damping in the offset process. For this reason, too, it is therefore expedient not to carry out any modification below this area coverage limit.
Furthermore, the modified characteristic curve of printing is based on the observation that the modified dot gain is also to be set lower in the case of high area coverages. One reason for this, at least for the range of high area coverages, is probably that in modern reproduction processes corresponding screen dots are circular, so that from an area coverage of more than approximately 60% on neighboring screen dots start to overlap and also in the printing of all screen dots of a screen, the area coverage is not complete, i.e., does not correspond to a 100% area coverage. As it is difficult to keep small dots open in a complete color area, here, too, an unsuitable compensation can result in stronger color deviations than no compensation at all. The above difficulties occur, in particular, in offset processes with damping.
The modified characteristic curve of printing is a continuous and, in particular, continuously differentiable curve or predefined values which can be interpolated by such a curve. It is, however, advantageous for the curve to have a first monotonic range in which the modified dot gain starts from the zero point at low area coverage, increases towards a maximum and from this maximum decreases towards the zero point at high area coverage.
Owing to the fact that a modified—i.e. theoretical or hypothetical—characteristic curve of printing is predefined, this characteristic curve of printing has only few, quickly adjustable parameters. Even if an original is to be printed on different printing machines, the characteristic curve of printing does not have to be experimentally determined each time for each printing machine, but instead the modified characteristic curve of printing in accordance with the invention is predefined, and the available parameters are set so as to yield optimum results. An additional precondition may, however, be that, for example, the modified characteristic curve of printing in relation to the ideal characteristic curve of printing (the modified dot gain in relation to the area coverage of the original with a colored application) has a zero crossing at a finite area coverage, i.e., outside 0% and/or 100%.
The reproduction method for printing in accordance with the invention can be advantageously used for printing with printing inks which have a high density in the print, and, in particular, have a density which so far has not been customary in offset printing. Such increased densities are achieved by increased concentrations of pigment in the printing inks and also by a higher application of ink. This, in turn, means an increased layer thickness and therefore an increased dot gain, as, in principle, a thicker layer of printing ink can also undergo deformation to a greater extent (be squeezed out further) than is the case with a thinner layer of printing ink. Printing inks for printing at a higher density are described in DE 100 03 071 A1 and in EP 1 120 445 A2, to which reference is hereby expressly made.
A corresponding set of printing inks comprises the color tones yellow, red or magenta, cyan and black, and the difference of the optical density (logarithm of opacity) of the printing ink in the color tone black from the density of the printing ink in the chromatic tone with the highest density in the print is approximately 0.5. It has been found that use of printing inks where there is this difference value results in density ranges of 2.2 and higher. This 0.5 value is presumably determined by the physiological properties of the human ability to see colors, i.e., in particular, by the arrangement and formation of the rods and cones in the eye and by the signal processing in the brain. It seems that this value is universal. In a variant of an embodiment, the color tone of the chromatic color with the highest density is cyan.
Furthermore, provision may be made for the difference of the optical density between chromatic colors with neighboring density values to be 0.1 or, if this difference is larger, to lie as close as possible to 0.1. This 0.1 value also seems to be determined by the properties of the human system of seeing colors. With correspondingly produced printing inks a high density range is then achievable in printing. It may happen that in the case of a high density of a printing ink, if the difference value of 0.1 was selected, a process color tone cannot be distinguished by the human eye from identical color tones with lower density values. For example, a yellow color tone with a density of 2.3 cannot be distinguished from one with the value 2.0. In such a case, it is therefore expedient to diverge from the above rule in order to keep the production costs of the printing ink low and to facilitate handling during the printing. The difference should then be selected as close as possible to a value of 0.1.
In order to achieve a high density range it is particularly advantageous for the optical density of the printing ink in the color tone black to be at least 2.3.
Printing inks are usually made from a mixture of a binder, a colorant and printing additives. In a first embodiment of a set of printing inks, the aforesaid preconditions are met. In particular, the colors are advantageously produced by the proportion of colorant lying as proportion of pigment in the range of between 10% and 30% in the printing ink. The binder advantageously comprises phenol-modified colophony resin dissolved in oils such as mineral oil, vegetable oils or derivatives thereof.
The set of printing inks according to the first embodiment with a density range of up to 1.9 meets the German Industrial Standard 16539 relating to a color scale for offset printing. The corresponding colors are also referred to as Euroscale. The inventive set of printing inks can therefore be used both “conventionally” at a lower density range and at a higher density range.
In a second embodiment of such a set of printing inks, the proportion of colorant advantageously lies as proportion of pigment in the range of between 15% and 40%. Modified phenol resin in oil is used as binder. Mineral oil, vegetable oil or derivatives thereof can be used as oil.
With such a set of printing inks one obtains on account of the high proportion of pigment a very high density range which can be 2.4 or more. Density ranges of 2.8 to 3.0 have already been achieved.
It is expedient for the modified characteristic curve of printing in relation to the ideal characteristic curve of printing to correspond to the dependence of a modified dot gain upon the area coverage of an original with a colored application. The modified dot gain is not a real—experimentally measured—dot gain, but an externally predefined hypothetical—theoretical—dot gain.
In particular, it is advantageous for the zero crossing of the modified characteristic curve of printing at low area coverages to lie in the range of between 3% and 30% area coverage, and, advantageously, to lie at area coverages of between 5% and 25. The modified dot gain in the range of low area coverages is thereby reduced.
It has also proven advantageous for the zero crossing of the modified characteristic curve of printing in relation to the ideal characteristic curve of printing at high area coverages to lie in the range of between 90% and 98% area coverage, and, in particular, in the range of between 95% and 98% area coverage. As a result of this, reproductions with color fidelity in the print have also been achieved at high area coverages.
Very good results have been achieved when the zero crossing of the modified characteristic curve of printing at low area coverage has a flatter slope than the zero crossing at high area coverage. Printed reproductions of originals with high color fidelity have thereby been obtained. With low area coverages, the printed dots are smaller in size and the dot gain should not be overcompensated. As the area coverage increases, the compensation should gradually increase. With large area coverages, on the other hand, dots are printed over one another (in the case of square screen dots this partially occurs at overlapping ends), which results in a “negative” screen. There should then be a steeper drop in the dot gain compensation in order to keep the influence of this negative screen low.
In particular, the slope of the zero crossing at low area coverage lies in the range of between 20° and 30° and the slope of the zero crossing at high area coverage in the range of between 25° and 35°.
It is particularly advantageous for the modified characteristic curve of printing to be predefined by a mathematical function. A suitable transformation of data relating to the original to data for the printing is then quickly achievable with such a function containing few clear parameters, and, where appropriate, an adaptation can be carried out using one or several of the parameters of the predefined mathematical function in order to optimize the printing results with respect to color fidelity.
In practice, excellent results have been obtained when the predefined mathematical function comprises several and, in particular, two arcs of a circle. An arc of a circle has further parameters which are predefined by the position of the center point of the circle forming the arc of a circle and by the radius of the circle forming the arc of a circle and which are correspondingly adjustable. In the case of one arc of a circle there are then three parameters which are adjustable (on the additional condition of generation of a continuously differentiable curve of the modified characteristic curve of printing). This is clear and easy for the operator to carry out. In particular, it is also possible for the modified characteristic curve of printing to be made up of two arcs of a circle so as to obtain different slopes at the zero crossings of low area coverage and high area coverage.
It is also possible for the predefined mathematical function to be one or several arcs of an ellipse, a parabola or a hyperbola.
In addition to predefining the zero positions of the modified dot gain in relation to the area coverage of the original, the modified absolute size of the dot gain (the theoretical maximum size of the dot gain) also plays a part in obtaining a reproduction with color fidelity. It has been found that good results are achieved when the modified characteristic curve of printing in relation to the ideal characteristic curve of printing has a maximum percent dot gain which is less than 30%. Very good results have been obtained, in particular, also for printing inks with high density in the print, when the maximum percent dot gain lies in the range of 5% to 30%, and, for example, at 10%.
Furthermore, very good printing results are achieved when a modified black color characteristic curve of printing is used for black in the print, i.e., when a modified characteristic curve of printing separate from the other color tones (chromatic color tones) is used. It has proven advantageous in printing at higher density for the standard density of black to have a certain density difference of, for example, 0.5 relative to the chromatic printing colors. This is disclosed in DE 100 03 071 A1 and EP 1 120 445 A2, to which reference is hereby expressly made. The difference of the density of black in the print from the density of the chromatic colors can then be taken into account by a modified characteristic curve of printing of its own. Accordingly, it is expedient to use a modified chromatic color characteristic curve of printing of its own or modified chromatic color characteristic curves of printing separated according to the chromatic colors for the chromatic colors.
The inventive process has produced excellent reproduction results, in particular, for printing with printing inks with increased density in the print. In printing with increased density, the printing inks are applied with an increased layer thickness, so that there is also the possibility of stronger deformation here and the problem of dot gain is thus intensified. By predefining a modified characteristic curve of printing in accordance with the invention this increased dot gain can be compensated to such an extent that excellent printing results are obtained.
In particular, good results have been obtained when the standard density in the print in the case of the printing ink with the lowest density lies at least at approximately 1.6.
It is advantageous to use a CMYK set of process colors for the printing.
Particularly good results were achieved for high printing densities when, for example, the standard density in the print with the printing inks in the color tone yellow (Y) lies at approximately 2.0, in the color tone magenta (M) at approximately 2.4, in the color tone cyan (C) at approximately 2.5, and in the color tone black (K) at approximately 3.0.
In particular, printing inks made from a mixture of a binder, a colorant and printing additives, in which the proportion of the colorant in a printing ink as proportion of pigment lies in the range of between 15% and 40%, can be used as printing inks with high density in the print. Such printing inks are described in DE 100 03 071 A1 and EP 1 120 445 A2, to which reference is hereby expressly made.
In a variant of an embodiment the transformation from the original to printing data comprises a color space transformation from an RGB color space to a CMYK color space in order, for example, to be able to print with a printing machine an original from a monitor or a slide.
The inventive reproduction method for printing can be used with advantage in offset printing.
It is particularly advantageous for the modified characteristic curve of printing to be entered in a color management system. Adobe Photoshop, for example, is used as such a color management system. (Adobe and Photoshop are registered trademarks of Adobe Systems Incorporated.) Color data are processed by color management systems so that starting from an original a printed reproduction results which corresponds with respect to color to the original. With color management systems a colored reproduction corresponding to the original is also obtainable in modern reproduction environments. Attention is called in this connection to the publication cited at the outset “PHILOSOPHIE UND TECHNIK DES COLOR MANAGEMENT”, to which reference is expressly made. Such color management systems often have interfaces via which experimental characteristic curves of printing can be entered. Entering the modified characteristic curve of printing according to the invention in a color management system yields good reproduction results in respect of compensation of the dot gain in a simple way.
It is also important that when the modified characteristic curve of printing is used within the framework of a color management system and individual values are entered, the values lie close enough to ensure that the predefined modified characteristic curve of printing is taken into account. In particular, it is important that at the edges of the curve the values be sufficiently close at the zero crossings as it is there that the dot gain has the greatest influence on the color fidelity.
The following description of preferred embodiments serves in conjunction with the drawings to explain the invention in greater detail.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a schematic illustration of the reproduction of an original in a print;
FIG. 2 a shows schematically a screen dot saturated with printing ink on an offset plate;
FIG. 2 b shows the ink dot after transfer onto a rubber blanket, and
FIG. 2 c shows the ink dot after transfer onto the paper in print;
FIG. 3 shows a typical characteristic curve of printing and an ideal characteristic curve of printing; and
FIG. 4 shows two embodiments of predefined modified characteristic curves of printing as modified dot gain in relation to an area coverage in the plate of the original.
DETAILED DESCRIPTION OF THE INVENTION
To produce a print 10 from an original 12 , one proceeds, for example, as shown in FIG. 1 , by generating from the original 12 , for example, a slide, color separations (color proofs) in an RGB color space containing the process colors red (R), green (G) and blue (B) using a scanner. These data are converted by a transformation 14 into data, for example, of a CMYK color space containing the process colors cyan (C), yellow (Y), magenta (M) and black (K).
Intermediate transformations from RGB to LAB and then from LAB to CMYK may also be performed. In this connection, reference is made to the publication cited at the outset “PHILOSOPIE DES COLOR MANAGEMENT”.
Colorimetrically, the transformation represents a unique association of a color space with a reference color system. For example, a corresponding color value from the reference system is associated with each RGB value of a scanner color space. A standard, the so-called ICC (International Color Consortium) standard, applies to the device-independent reference or association color space.
The color transformation can be performed using mathematical models such as, for example, matrix operations or reference tables.
The data file in the CMYK color space is process-specific, for example, there are different data files for intaglio printing, offset printing or screen printing.
In the example of offset printing, the color separations are then screened separately for R, G and B and copied onto an offset plate which, in particular, is formed by a grained zinc plate. In the offset machine, the offset plate is fixed on a plate cylinder and serves to take the printing ink from the ink rollers onto the parts carrying the image. The printing ink is transferred onto the paper via a rubber blanket fixed on a cylinder so as to reproduce the original thereon. The printing inks with the color tones C, Y and M are printed over one another together with a black plate for increasing the contrast.
FIGS. 2 a , 2 b , and 2 c show schematically ink dots in the transition from the offset plate onto the paper. FIG. 2 a shows an offset plate 16 with an ink dot 18 . FIG. 2 b shows the same ink dot 18 ′ after transfer onto a rubber blanket 20 .
Owing to impression pressures exerted during the transfer from the offset plate to the rubber blanket 20 , the ink dot 18 ′ is squeezed, i.e., the dot area of the ink dot 18 ′ increases as a result of the impression pressure to which the layer of ink 18 lying on a screen dot is subjected during the transfer.
Finally, FIG. 2 c shows the same ink dot 18 ″ after transfer onto paper 22 . Here, too, a further squeezing (dot gain) occurs on account of impression pressures to which the ink dot 18 ′ is subjected during the transfer from the rubber blanket 20 to the paper 22 .
The extent of the increase in the dot area of the dot 18 ″ in comparison with the dot 18 on the offset plate 16 depends, aside from the dependence on the impression pressures, in particular, on the amount of ink made available to the offset plate 16 by the ink rollers. The heavier the ink application during printing, the greater is the dot gain that is to be anticipated.
In addition, the dot gain is also dependent upon the condition of the rubber blanket 20 , the printing speed, the quality of the printing ink and the quality of the paper on which the printing is done.
FIG. 3 shows the area coverage in the print as a function of the area coverage in the plate. The corresponding curve 24 is referred to as characteristic curve of printing. This shows the dependence of the dot gain on the parameters of the printing process, i.e., as described above, in particular, the impression pressures during the transfer from the offset plate 16 to the rubber blanket 20 and from there onto the paper 22 , the condition of the rubber blanket, the printing speed and also the layer thickness. Aside from the density in the print, the characteristic curve of printing 24 thus also depends on the offset printing machine itself. The characteristic curve of printing 24 is usually determined experimentally for a certain printing machine.
Also drawn in FIG. 3 is an ideal characteristic curve of printing 26 in the event there were no dot gain, i.e., if the ink dots 18 on the offset plate 16 were transferable without squeezing as ink dots 18 ″ onto the paper 22 .
The dot gain, for example, the dot gain 28 at an area coverage of 50% of the plate, is the difference between the actual characteristic curve of printing 24 and the ideal characteristic curve of printing 26 .
The ideal characteristic curve of printing 26 is the line bisecting the angle between abscissa and ordinate (45° straight line).
In accordance with the invention, a modified characteristic curve of printing shown with reference to two exemplary embodiments in FIG. 4 is now predefined. The first embodiment of a modified characteristic curve of printing is designated by reference numeral 30 and the second embodiment by reference numeral 32 . The two modified characteristic curves of printing have in common that their zero crossings, i.e., their crossings at 0% dot gain, lie at a finite area coverage, i.e., outside 0% and 100%. However, there may also be zero crossings at 0% and/or 100% area coverage (not shown in the drawing).
In the first embodiment 30 , the zero crossing 34 of low area coverage lies at approximately 7% area coverage, and the zero crossing 36 of high area coverage at approximately 98% area coverage. This means that the modified dot gain on the basis of the modified characteristic curve of printing 30 is reduced towards zero area coverage in the case of low area coverages, i.e., this is set at a lower value than would, for example, be obtained in accordance with the measured characteristic curve of printing 24 according to FIG. 3 . In particular, in the range of area coverage between zero and the zero crossing 34 , the dot gain is set at zero (ideal characteristic curve of printing) by the modified characteristic curve of printing.
In the same way, the modified dot gain is reduced towards high area coverages, i.e., towards 100% area coverage, i.e., the dot gain is set at zero between the zero crossing 36 and 100% area coverage.
Furthermore, the modified characteristic curve of printing 30 extends flatter in the area of the zero crossing 34 than in the area of the zero crossing 36 at high area coverages. This is indicated by a corresponding tangent 38 of the modified characteristic curve of printing 30 drawn in broken lines at the zero crossing 34 . The tangent 40 at the zero crossing 36 of this modified characteristic curve of printing 30 is also shown. The acute angle of the tangent 38 to the abscissa (which corresponds to zero dot gain) is smaller than the corresponding acute angle between the tangent 40 and this abscissa.
For example, the angle of the tangent 38 to the abscissa lies in the range of between 20° and 30° and the acute angle of the tangent 40 to the abscissa in the range of between 25° and 35°.
In general, the zero crossing 34 lies in the range of between 3% and 30% area coverage and the zero crossing 36 in the range of between 90% and 98% area coverage.
Provision is made in accordance with the invention for the maximum 42 of the modified characteristic curve of printing 30 to be shifted towards high area coverages, i.e., it lies above an area coverage of 50% and, in particular, between an area coverage of 50% and 70%. In the case of the modified characteristic curve of printing 30 , this maximum 42 lies at an area coverage of approximately 70%.
The maximum 42 , i.e., the maximum percent dot gain lies at an area coverage above 50%. Only in the ideal case when the screen dots are rectangular and, in particular, square, does the maximum percent dot gain lie at an area coverage of essentially 50%. However, when the screen dots are, for example, circular, neighboring screen dots can overlap, and this can be effectively taken into account by the modified characteristic curve of printing having its maximum 42 above a 50% area coverage, and, in particular, in the range of between 50% and 70%, and, advantageously, at approximately 60% area coverage.
The maximum of the modified dot gain can be determined in the following way: Circular dots arranged like a checkerboard start to overlap at an area coverage of approximately 78% (π/4·100%). If one proceeds from a dot gain in the order of magnitude of between 10% and 25%, one then obtains at a maximum with approximately 60% area coverage with 25% dot gain an effective area coverage which lies at approximately 75% and thus close to the theoretical value of approximately 78% for the overlapping of exactly circular dots arranged like a checkerboard. Since, in practice, the printed dots are not exactly circular, very good results are obtained when the maximum 42 lies above a 50% area coverage, and, in particular, at approximately 60% area coverage.
In practice, very good reproduction results have been achieved with a modified characteristic curve of printing 30 , i.e., high color fidelity of the image reproduction in the print has been obtained over the entire range of the area coverage.
The modified characteristic curve of printing 30 , which, in particular, is a continuously differentiable curve, can be obtained in a simple way with a first arc of a circle 44 and a second arc of a circle 46 which are joined together in such a way as to produce a continuously differentiable transition. The different slopes at the zero crossings 34 and 36 can then also be set by the two different arcs of a circle 44 , 46 .
In the second embodiment 32 of a modified characteristic curve of printing, there is again a zero crossing at high area coverages which corresponds to the zero crossing 36 of the first embodiment 30 . At low area coverages there is a zero crossing 48 which lies at approximately 23% area coverage. A corresponding tangent 50 at the zero crossing 48 again extends at a smaller acute angle to the abscissa than the tangent 40 at the zero crossing 36 . In the case of the modified characteristic curve of printing 32 , the modified dot gain is thus only set at a finite value from area coverages of approximately 23% on and then increases monotonically towards the maximum 42 .
In comparison with the modified characteristic curve of printing 30 , the modified dot gain is even further reduced at low area coverages in the characteristic curve of printing 32 , i.e., the dot gain is not taken into account at low area coverages up to the zero crossing 48 in the characteristic curve of printing, and up to the zero crossing 48 one then proceeds from the ideal characteristic curve of printing.
The invention is based on the recognition that it is in the ranges of low area coverage at a sufficient distance from zero area coverage and in the ranges of high area coverage at a sufficient distance from 100% area coverage that the effect of the dot gain on the color fidelity is most disturbing, and, consequently, it is here that a calculated compensation for the dot gain is most necessary. Such a compensation can be achieved in a simple way by predefining in accordance with the invention a corresponding characteristic curve of printing in relation to the ideal characteristic curve of printing, and this has yielded very good results for the color fidelity.
In particular, a modified maximum dot gain which is a predefined value which need not necessarily correspond to an actual dot gain is set. In practice, very good reproduction results have been obtained with a maximum modified dot gain in the range of approximately 10%.
Aside from the formation of the modified characteristic curve of printing by two arcs of a circle, other mathematical functions may be chosen to obtain a modified characteristic curve of printing, e.g., with arcs of a hyperbola, arcs of an ellipse or arcs of a parabola. Good reproduction results have been obtained when the zero crossings of the modified characteristic curve of printing lie outside of an area coverage of the plate of 0% and 100%.
The predefined modified characteristic curve of printing is used as mathematical function or via predefined values of the modified characteristic curve of printing, for example, within the framework of a color management system such as Adobe Photoshop (Adobe and Photoshop are registered trademarks of Adobe Systems Incorporated). Such color management systems, which are described in the publication “PHILOSOPHIE UND TECHNIK DES COLOR MANAGEMENT” cited at the outset, enable alteration of the image generated, for example, by a scanner, in any way and to any extent, by strengthening or weakening image elements of the individual color separations. Experimentally determined characteristic curves of printing are or can be filed in such programs.
In accordance with the invention, the modified characteristic curve of printing is filed in such a color management system in order to achieve compensation of the dot gain in the print. This means that on the basis of the predefined theoretical characteristic curve of printing, printing inks are applied to a corresponding lesser extent in the area coverage to take the dot squeezing into account so that the dot gain is set so as to substantially maintain the color fidelity.
In particular, a dot gain caused by a larger layer thickness of printing ink can be compensated in accordance with the invention. In DE 100 03 071 A1 and EP 1 120 445 A2, printing inks are described with which density ranges of more than 1.8 are achievable. Reference is made expressly to these documents. Larger density ranges also mean that an increased ink application occurs, which, in turn, brings about increased layer thickness and an increased dot gain. In particular, such overproportionally high dot gains can be compensated in accordance with the invention by predefining modified characteristic curves of printing with zero crossings of the dot gain outside zero area coverage and complete area coverage of the plate.
While various exemplary embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention. | To provide a reproduction method for printing wherein characteristic data of an original are transformed into data required for printing, with the dot gain being controllable so as to yield optimum reproduction results in the print, it is proposed that a modified characteristic curve of printing which in relation to the ideal characteristic curve of printing has a maximum above an area coverage of 50% be predefined for the transformation of the data in order to control the dot gain in printing. | 7 |
This is a division, of application Ser. No. 595,599 , filed Apr. 2, 1984, now U.S. Pat. No. 4,631,230.
FIELD OF THE INVENTION
The present invention relates generally to epoxy resin technology and is more particularly concerned with novel epoxy resin compositions having special utility in the production of composite molded bodies of electrical insulation because of their unique characteristics, and with new composite molded bodies comprising thermoplastic resin shells filled with and bonded to materials of those novel compositions.
CROSS REFERENCE
This invention is related to that of copending patent application Ser. No. 595,596, filed Apr. 2, 1984, now U.S. Pat. No. 4,621,212 filed of even date herewith in the names of Torossian, Heisler and Cox and assigned to the assignee hereof, which discloses and claims a novel conductor insulating method and resulting composite article and an unique clamshell mold having special utility in implementation of that method.
BACKGROUND OF THE INVENTION
The long-standing, generally recognized need for a better way to provide insulation for conductors such as the series loops of the stators of large, fluid-cooled, electric generators was finally met by the invention of the above-referenced patent application. Thus the difficulty and high labor cost of the standard manual taping and patching procedure of the prior art can be avoided and the shortcomings and derelictions of the potting and casting attempts of the prior art can be overcome by applying the principles of that invention. In essence, according to those principles a composite body of insulating material is formed over the exposed part of a series loop by enclosing that part in a clamshell mold of thermoplastic resin insulating material, then filling the mold with thermosetting resin insulating material and curing the latter and thereby bonding it to both the shell and the exposed part of the series loop. By virtue of the fact that two half shells of the clamshell mold are formed for adjustable interfitting engagement of their overlapped opposed edge portions the mold can be easily assembled and secured in place around the part of a series loop to be insulated. Then the thermosetting resin material can be injected into the mold and cured at room temperature to bond the resulting integral composite body of mold and fill to the exposed part of the conductor to be insulated. The thermosetting resin material thus on curing bonds well to both the thermoplastic mold and to the metallic conductor and in addition to having requisite dielectric strength has good shelf life, flowability enabling complete filling of the mold under moderate pressure, and in cured form is resistant to cracking on accelerated thermal cycling tests.
SUMMARY OF THE INVENTION
We have discovered that the service life of these new composite insulating bodies can be substantially increased, making the invention of patent application Serial No. 595,596, filed Apr. 2, 1984, now U.S. Pat. No. 4,621,212 of even greater importance as an advance in this old, well-developed technological field. Further, we have been able to make this gain without incurring any significant offsetting disadvantage of cost or compromise of any desirable feature or property of the ultimate product.
A key discovery of ours upon which this invention is predicated is that epoxy resin compositions which are generally well qualified for use as fill or molding compositions because of their superior adhesive properties, thermal stability, resistance to solvents, oils and water, and their dielectric strengths, can be modified so that they do not tend to generate cracks in composite molded bodies leading to insulation breakdown. In particular we have found that stress cracking of the thermoplastic mold by the epoxy resin fill and thermal-cycle cracking of the epoxy resin fill itself can be avoided while the impact strength of the fill and of the ultimate composite body is substantially increased by incorporating certain polyglycol diepoxides in critical proportions in epoxy resin compositions such as those disclosed in the above-referenced patent application. Specifically, polyglycol diepoxides having viscosity of at least 2,000 centipoises (cps) at 25° C. when used in proportion to the epoxy resin of about 1-3 to 3-1 have been found to be effective in this manner and with these results. Further, additions of glycidyl ether of an aliphatic alcohol having 8 or more carbon atoms have been found effective to modify the viscosity of the epoxy resin molding compositions without causing subsequent stress cracking of the thermoplastic mold even when it is of polycarbonate resin. These results are unexpected because other polyglycol diepoxides and glycidyl ethers of phenol, butanol and neopentyl glycol used in the same manner cause stress cracking of polycarbonate resin shells.
In making additions of glycidyl ethers to reduce viscosity and thus improve flow characteristics of the epoxy resin molding compositions, the amounts used should be between about five and 25% on the basis of the epoxy resin mixture. Preferably the aliphatic alcohol of the glycidyl ether is one having from 8-14 carbon atoms in the molecule.
The compositions of this invention also contain a phenolic accelerator and an organic titanate having only titanium-to-oxygen primary valence bonds. These latter two constituents are in small but effective amounts being respectively from about 0.1-15% and 0.5-10% on the basis of the epoxy resin mixture. In other words the cure chemistry of the molding compositions of this invention is based upon the invention disclosed and claimed in U.S. Pat. No. 3,776,978 issued Dec. 4, 1973 to Mark Markovitz and assigned to the assignee hereof. Thus the proportions of phenolic accelerator and organic titanate stated above are based upon the total epoxy resin content of the molding composition in each case so that, for instance, when two epoxy resin formulations are combined as described below, the amounts of phenolic accelerator and organic titanate in the ultimate mixture will be within the above ranges.
A new composite molded body of this invention produced through the use of one of these novel epoxy resin compositions by the method disclosed and claimed in reference patent application Serial No. 595,596, filed Apr. 2, 1984, now U.S. Pat. No. 4,621,212 comprises a shell of thermoplastic material filled with the epoxy resin composition in cured form bonded to the shell. In typical use the composite body itself is bonded by the cured resin composition to a conductor which is thereby electrically insulated. Thus as applied to the exposed portion of a series loop of the stator of a large electric generator, the shell is a clamshell mold of two half shells disposed around and enclosing the exposed part of the metallic body to be insulated. With the half shells sealed tightly together, the mold cavity is filled completely with a resin composition of the present invention which is then cured in situ and thereby firmly bonded to both the mold shell and enclosed conductor portion. As disclosed also in the aforesaid referenced patent application, the thermoplastic mold shell may be of one or another of several different thermoplastic materials such as bisphenol-A polycarbonates such as General Electric Company's Lexan® resin, or polyester material such as made from 1,4-butanediol and terephthalic acid such as General Electric Company's Valox® resin, Celanese Company's Celanex® resin or Eastman Kodak's Kodapak®, or polysulfones, polyetherimides, and the like. In other words, all these thermoplastic materials are eligible for such use and can be expected to produce consistently good results as described above when applied and used in accordance with the teachings of this invention as set out herein.
In its composition of matter aspect the present invention, generally described, is an epoxy resin mixture of 25-75% of 1,2 epoxy resin having at least two epoxide groups per molecule and 75-25% of a polyglycol diepoxide having viscosity from 2,000-5,000 cps and in addition small but effective amounts both a phenolic accelerator and a catalytic hardener. As an additional constituent for purposes of improving flowability through adjustment of viscosity, a glycidyl ether of an aliphatic alcohol having from 8-14 carbon atoms per molecule may be incorporated in the resin composition. Further this latter optional constituent may be used as an admixture of two or more such ethers. Our preference, in fact, is to use the glycidyl ether of a mixture of 8-10 carbon atom alcohols or of 12-14 carbon atom alcohols.
BRIEF DESCRIPTION OF THE DRAWINGS
A further and better understanding of this invention and the new results and advantages which it affords will be gained by those skilled in the art upon consideration of the detailed description of preferred embodiments illustrated by the drawings accompanying and forming a part of this specification, in which,
FIG. 1 is a view in perspective of a clamshell mold assembled with an installed stator series loop so as to enclose the portions of the loop, stator bars and ground insulation to be insulated or covered by a thermosetting resin composition of this invention filling the mold chamber or cavity;
FIG. 2 is a fragmentary elevational view of an extremity of the mold of FIG. 1 showing the series loop liquid-coolant line and sponge elastomeric material seal therefor; and,
FIG. 3 is a side-elevational view of the mold of FIG. 1 filled with the resin composition of this invention cured and bonded to the mold shell, the series loop components and stator bar end portions within the mold chamber, parts being broken away for clarity.
DETAILED DESCRIPTION OF THE INVENTION
As shown in the drawings, a composite molded body 10 (FIG. 3) of a preferred form of this invention comprises a thermoplastic mold 12 (FIG. 1), suitably a clamshell consisting of two half shells 14 and 16 secured together with their edges interfittingly overlapped and sealed. Further, mold 12 is so designed and constructed of polycarbonate resin that it can be readily applied to and installed on a series loop 18 of a stator of a large electric generator to enclose in the cavity of the mold parts 19, 20 and 21 of the series loop to be electrically insulated, as well as ends 23 and 24 of stator bars 25 and 26, respectively. With the mold thus assembled and applied as disclosed and described in detail in above-referenced copending patent application (the substance of which pertaining to the structure, design and method of use of the mold are hereby incorporated herein by reference), a novel composition of the present invention is introduced under pressure into the mold through sprue sub-assembly 28 to fill the mold cavity. That composition is then cured at room temperature in situ in contact with the interior surface of the mold and with the parts of the series loop and associated stator bars enclosed in the mold to provide a bonded composite insulating structure which is also bonded to the series loop and the stator bar portions as illustrated in the drawing. Cured resin fill body 29 (FIG. 3) thus covers completely series loop parts 19, 20 and 21 and stator bar end portions 23 and 24 including parts thereof wrapped with ground insulation as shown at 30 and 31.
In using a novel room-temperature gelling or curing composition of this invention one has a choice between one-part and two-part resin systems. The former as a catalyzed molding compound is flash frozen to preserve its stability and then at the time of use is rapidly heated, for example, by microwave radiation, to convert it to liquid or flowable form in which it can be injected into the mold through sprue sub-assembly 28. The alternative is to mix the two reactive constituents (resin component A and resin component B) just prior to introducing the composition into the mold.
A preferred epoxy molding composition is one in which Part A and Part B can be used in about 1.0 to 1.0 ratio for optimum properties of the cured insulation product. There is however, substantial latitude in these proportions in the practice of this invention, as indicated above and set out in more detail below.
A number of experiments have been performed in exploring the parameters of this invention. Thus in some of the illustrative, but not limiting, examples set forth below the criticality of the molecular carbon content of the aliphatic alcohol of glycidyl ether in terms of stress cracking of the polycarbonate mold shell is demonstrated. Also in some examples, the substantial variation from preferred 1.0 to 1.0 ratio of Parts A and B that is possible without major detrimental effect upon the performance of the molding composition or compound is established.
EXAMPLE 1
A two-part resin system was made in a proportion of 1.0 to 1.0 ratio consisting of the following as Part A:
______________________________________ Parts by Weight (pbw)______________________________________Epon 828 (bisphenol-A 25.5diglycidyl ether resin)Catechol 1.54Cab-O-Sil TS 200 (fumed silica) 1.0Min-U-Sil 30 (30-micron silica) 9.491/32" glass fibers 11.631/8" glass fibers 0.85______________________________________
and Part B:
______________________________________ Parts by Weight______________________________________Epon 828 (bisphenol-A diglycidyl 25.5ether epoxy resin)Tetraoctylene glycol titanate 1.54Cab-O-Sil TS 200 (fumed silica) 1.0Min-U-Sil 30 (30-micron silica) 9.491/32" glass fibers 11.631/8" glass fibers 0.85______________________________________
Under accelerated conditions of thermal cycling described below, specimens of the resulting cured resin body failed the test by forming cracks.
In the foregoing experimental test, thermal crack resistance, or more exactly, thermal shock crack resistance, was measured by filling a cylindrical mold made from a 1.0 inch by 1.0 inch square and an 8-inch long steel bar which was centered inside a 1/8th-inch thick, 2.0-inch inside diameter and 8-inch long Plexiglas® resin tube. The sharp corners of the steel bar act as stress risers. The molding compound under test was cured 24 hours at room temperature followed by 24 hours at 105° C. post cure. The 8-inch long sample was cut into four 11/2-inch thick slices (one-inch end portions being cut off and discarded) thereby exposing a cross section of the molded resin body with the square steel rod embedded in it. The 1.5-inch high sample in each instance was tested by heating 30 minutes at 130° C. and then immediately dropping it into acetone at -70° C. and keeping the sample emerged 10 minutes at -70° C., the acetone being cooled with liquid nitrogen. The cured resin bodies were classified as passing the thermal shock test when four samples underwent 10 cycles (therefore, a total of 40 test points) without any crack appearing in them.
EXAMPLE 2
Another molding compound was made which was identical to that of Example 1 except that the 25.5 parts by weight of Epon 828 used in Parts A and B was replaced by Epon 828 (16.6 pbw) and polyglycol diepoxide (8.9 pbw) having viscosity of 55-100 cps at 25° C.
Under the same thermocycling test as described in Example 1, the resin product body passed the thermal cycling test but severely stress cracked the polycarbonate shell to which it was bonded on curing.
EXAMPLE 3
Another molding compound prepared as described in Example 1 in a 1.0 to 1.0 ratio of Parts A and B was made consisting of Part A:
______________________________________ Parts by Weight______________________________________Epon 828 (bisphenol-A diglycidyl 12.65ether epoxy resin)Polyglycol diepoxide (viscosity 10.351,350 cps at 25° C.)Catechol 3.7Glass beads 20.31/8" glass fibers 1.51/32" glass fibers 1.75______________________________________
and Part B:
______________________________________ Parts by Weight______________________________________Epon 828 (bisphenol-A diglycidyl 12.65ether epoxy resin)Polyglycol diepoxide (viscosity 10.351,350 cps at 25° C.)Tetraoctylene glycol titanate 1.4Glass beads 20.31/8" glass fibers 1.51/32" glass fibers 1.75______________________________________
The resulting resin body bonded as in Example 2 to a polycarbonate test shell passed the thermal cycling test described above, but stress cracked the polycarbonate shell.
EXAMPLE 4
Another molding compound was made which was identical to the one described in Example 3, but the polyglycol diepoxide used in Example 3 was replaced by a polyglycol diepoxide having a viscosity of 2,000-5,000 cps at 25° C. The resulting molding compound resin body again bonded on curing to a polycarbonate shell passed the thermocycling test described above and also did not crack the polycarbonate shell.
EXAMPLE 5
Still another 1.0 to 1.0 ratio molding compound of Parts A and B was made consisting of the following
Part A:
______________________________________ Parts by Weight______________________________________Epon 826 (bisphenol-A diglycidyl 10.8ether epoxy resin)Polyglycol diepoxide (viscosity 10.82,000-5,000 cps at 25° C.)Butyl glycidyl ether 2.39Catechol 3.9Cab-O-Sil TS 200 (fumed silica) 0.80Min-U-Sil 30 (30-micron silica) 9.581/32" glass fibers 11.621/8" glass fibers 1.35______________________________________
and Part B:
______________________________________ Parts by Weight______________________________________Epon 826 (bisphenol-A diglycidyl 10.8ether epoxy resin)Polyglycol diepoxide (viscosity 10.82,000-5,000 cps at 25° C.)Butyl glycidyl ether 2.39Tetraoctylene glycol titanate 1.43Cab-O-Sil TS 200 (fumed silica) 0.80Min-U-Sil 30 (30-micron silica) 9.581/32" glass fibers 11.621/8" glass fibers 1.35______________________________________
The butyl glycidyl ether was used to decrease viscosity and improve the flow properties of the compound. The resin body produced on curing of this composition and bonded to the polycarbonate test shell passed the thermal cycling test, but stress cracked the polycarbonate shell.
EXAMPLE 6
Still another molding compound was prepared which is identical to that of Example 5 except that the butyl glycidyl ether was replaced by neopentyl glycol diglycidyl ether. The resulting cured resin body bonded to a carbonate test shell as described above also stress cracked the polycarbonate shell.
EXAMPLE 7
Still another molding compound was made according to the prescription of Example 5, except the butyl glycidyl ether was replaced by phenyl glycidyl ether. Again, upon curing that compound bonded to the polycarbonate test shell stress cracked the polycarbonate shell.
EXAMPLE 8
Again a compound identical to that of Example 5, except for replacement of the butyl glycidyl ether with 2-ethylhexyl glycidyl ether was prepared. That compound cured and bonded to the polycarbonate test shell passed the thermal cycling test and did not crack the polycarbonate shell. It was found upon hardness testing that the resulting resin body in final cured condition has a Shore D hardness of 43 after 24 hours at room temperature. This hardness index increased to 71 after a post cure for 24 hours at 105° C. This ultimate product passed the thermal shock test without any failure and did not stress crack the polycarbonate test sheet material.
EXAMPLE 9
Another compound identical to that of Example 5 except for replacement of the butyl glycidyl ether with the glycidyl ether of a mixture of C 8 to C 10 alcohols was prepared and cured in contact with a polycarbonate test shell. The resulting resin body passed the thermal cycling test and did not stress crack the polycarbonate shell.
EXAMPLE 10
In another experiment involving the use of the composition of Example 5, except for replacement of the butyl glycidyl ether with the glycidyl ether of a mixture of C 12 to C 14 alcohols, a resin body was produced on curing in contact with polycarbonate test shell which passed the thermal cycling test and did not crack the polycarbonate shell.
EXAMPLE 11
Using the composition of Example 8, except that Part A was used in the diminished proportion of 0.71 pbw to 1.0 pbw of Part B, the resulting cured body proved to have Shore D hardness after 24 hours at room temperature of 37 which increased to 70.5 after 24 hours at 105° C. post cure. The cured molding compound passed the thermal shock test without any failure and did not stress crack the polycarbonate test sheet material to which it was bonded.
EXAMPLE 12
Again using a molding composition the same as that of Example 8 but for a larger proportion of Part A (1.25 pbw Part A to 1.00 pbw Part B) resulted in a cured resin body of Shore D hardness of 45 after 24 hours at room temperature. That hardness index was increased to 73 after 24 hours at 105° C. post cure. The ultimate cured molding compound passed the thermal shock test without any failure and did not stress crack the polycarbonate test shell.
Wherever in the present specification and in the appended claims amounts, proportions or percentages are stated, reference is to the weight basis unless otherwise expressly noted. | A thermosetting resin composition of an epoxy resin mixture of 1,2 epoxy resin having at least two epoxide groups per molecule and a polyglycol diepoxide having viscosity of 2,000-5,000 centipoises at 25° C. and in addition small but effective amounts of both a catalytic hardener and an accelerator has special utility in the production of composite molded bodies of electrical insulation having thermoplastic shells because of its unique combination of properties including thermal stability, thermal-cycling crack resistance, high impact strength, toughness, room-temperature curability and bondability to both thermoplastic and metallic surfaces, and because it does not stress crack thermoplastic shells to which it is bonded in curing. | 2 |
TECHNICAL FIELD
[0001] The present invention relates to blow-molded bottles of the type used for containing viscous food products such as peanut butter and the like. In particular, it relates to a bottle having a shape that is particularly conducive to complete evacuation of the product from the bottle by the ultimate consumer when using a typical butter knife or other utensil.
BACKGROUND AND SUMMARY
[0002] Conventional blow-molded bottles made from synthetic resinous materials such as polyethylene terephthalate (PET) and used to contain viscous food products such as peanut butter are provided with straight or inclined sidewalls in the body portion of the bottle below the shoulder portion. Typically, the ultimate consumer will use a butter knife with a radiused knife edge to periodically remove servings of the product from the bottle. As the contents are depleted, the consumer usually scrapes along the interior sidewall of the bottle in an effort to remove all of the product, but in many instances it is difficult or virtually impossible to achieve complete product evacuation because of the mismatch between the bottle configuration and the knife. As a consequence, the consumer may become frustrated and even angry, perhaps to such an extent that he rejects the product brand or at least diminishes his enthusiasm for the product.
[0003] Accordingly, an important object of the present invention is to provide a blown bottle having a unique configuration that renders the bottle particularly suitable for containing viscous food products, such as peanut butter, and which is especially conducive to complete or nearly complete product evacuation using a conventional butter knife.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a side elevational view of a blown bottle constructed in accordance with the principles of the present invention;
[0005] FIG. 2 is a top plan view thereof;
[0006] FIG. 3 is a bottom plan view thereof;
[0007] FIG. 4 is a schematic illustration of the bottle of FIGS. 1-3 for the purpose of illustrating the relationship of the various diametrical and curvature features of the bottle to one another;
[0008] FIG. 5 is a schematic illustration of the bottle of FIGS. 1-3 showing exemplary dimensions for various features of the bottle;
[0009] FIG. 6 is a schematic representation of a typical butter knife used by a consumer in evacuating the contents of the bottle;
[0010] FIG. 7 is a schematic view of a second embodiment of a bottle constructed in accordance with the principles of the present invention;
[0011] FIG. 8 is a schematic illustration of a third embodiment of a bottle constructed in accordance with the principles of the present invention;
[0012] FIG. 9 is a schematic illustration of a fourth embodiment of a bottle constructed in accordance with the principles of the present invention; and
[0013] FIG. 10 is a schematic illustration of a fifth embodiment of a bottle constructed in accordance with the principles of the present invention.
DETAILED DESCRIPTION
[0014] The present invention is susceptible of embodiment in many different forms. While the drawings illustrate and the specification describes certain preferred embodiments of the invention, it is to be understood that such disclosure is by way of example only. There is no intent to limit the principles of the present invention to the particular disclosed embodiments.
[0015] Referring initially to FIGS. 1-3 , bottle 10 in accordance with one embodiment of the invention broadly comprises an uppermost, annular seal surface 12 for sealing against a closure cap or the like (not shown), an annular neck finish 14 immediately below seal surface 12 (in the particular disclosed embodiment, neck finish 14 includes external threads 14 a for use in securing the closure cap to the bottle), a lowermost base surface 16 spaced below neck finish 14 and forming the bottom of bottle 10 , and an annular sidewall 18 extending between neck finish 14 and bottom surface 16 . Sidewall 18 includes a radially outwardly disposed, convexly arcuate shoulder portion 20 immediately below neck finish 14 , a radially inwardly disposed, concave pinch portion 22 immediately below shoulder portion 20 , and a radially outwardly disposed, convex body portion 24 immediately below pinch portion 22 and above bottom surface 16 .
[0016] Preferably, bottle 10 is blow-molded and is constructed from a suitable synthetic resinous material such as polyethylene terephthalate (PET). In the particular embodiment of FIGS. 1-3 , shoulder portion 20 is outwardly convexly arcuate in a continuous manner from the intersection with neck finish 14 to the tangent point with pinch portion 22 . Likewise, pinch portion 22 is continuously concavely arcuate from its tangent point with shoulder portion 20 to its tangent point with body portion 24 . Body portion 24 is preferably continuously convexly arcuate from its tangent point with pinch point 22 to its intersection with bottom surface 16 . However, as will be seen in the discussion of alternative embodiments below, it is also possible to have any one or more of shoulder portion 20 , pinch portion 22 , and body portion 24 configured so as to be other than continuously arcuate.
[0017] In accordance with the present invention, the maximum diameter of shoulder portion 20 is greater than the minimum diameter of pinch portion 22 and less than or equal to the major diameter of body portion 24 . Furthermore, as illustrated in FIG. 4 , the axial distance B between shoulder portion 20 at its maximum diameter and the pinch portion 22 at its minimum diameter is greater than or equal to 2.5 A, where A is a value determined by the equation:
[0000]
A
=
maximum
shoulder
diameter
minus
minimum
pitch
diameter
2
[0000] Distance B is always measured from a point on shoulder portion 20 at its maximum diameter that is farthest from the bottom extremity of neck finish 14 to a point on pinch portion 22 at its minimum diameter that is closest to the bottom extremity of neck finish 14 .
[0018] The minimum pinch diameter at pinch portion 22 is equal to or greater than the maximum diameter of sealing surface 12 and, preferably, is within the range of 1.00 to 1.10 times the maximum diameter of sealing surface 12 . The overall height of bottle 10 from sealing surface 12 to bottom surface 16 is within the range of 1.5 to 2.0 times the maximum diameter of sealing surface 12 . Preferably, the overall height is within the range of 1.00 to 1.75 times the major diameter of bottle 10 in body portion 24 .
[0019] Sidewall 18 has a radius of curvature in body portion 24 that is within the range of 1.70 to 2.38 times the maximum diameter of sealing surface 12 . The swing point of the radius of curvature of body portion 24 , designated by the numeral 26 in FIG. 4 , is located between the level of sealing surface 12 and bottom surface 16 . Preferably, swing point 26 is spaced downwardly from the level of sealing surface 12 by a distance that is in the range of 0.60 to 0.70 times the overall height of bottle 10 .
[0020] FIG. 5 illustrates one set of exemplary dimensions for a bottle that incorporates the relationships as set forth above. In this exemplary product, the overall height of the bottle is 4.9521 inches, the sealing surface diameter is 2.6240 inches, the diameter of shoulder portion 20 is 2.7766 inches, the diameter of pinch portion 22 is 2.7216 inches, and the major diameter in body portion 24 is 3.3043 inches. The radius of curvature of shoulder portion 20 is 0.4739 inches, the radius of curvature of pinch portion 22 is 1.5120 inches, and the radius of curvature of the body portion 24 is 6.000 inches. Swing point 26 is located 3.070 inches down from the sealing surface 12 and 4.3478 inches laterally from the central axis of bottle 10 . The value for A is 0.0275 inches, and the value for the axial distance B between shoulder portion 20 at its maximum diameter and pinch portion 22 at its minimum diameter is 0.3293 inches. In bottle 10 , B is therefore considerably greater than 2.5 times A. Other dimensional values are also set forth in FIG. 5 .
[0021] FIG. 6 shows a typical butter knife 28 that a consumer might use in the process of evacuating product from bottle 10 . Butter knife 28 has a handle 30 and a blade 32 projecting forwardly from handle 30 . Blade 32 has an arcuate knife edge 34 at one radius of curvature, and an arcuate tip 36 at a sharper radius of curvature. Although knives are conventionally provided in a myriad of different shapes and sizes and with different radii of curvature for the knife edge 34 , a radius of curvature of 6.00 inches for knife edge 34 appears to be an average value. The bottle 10 of the present invention is well suited for evacuation using a knife having an edge 34 with a radius of curvature of approximately 6.00 inches, although such dimension is not critical to the present invention.
ALTERNATIVE EMBODIMENTS
[0022] FIG. 7 illustrates a second embodiment of the invention and comprises a bottle 110 that is identical to the bottle 10 , except in the shoulder portion. In bottle 110 shoulder portion 120 has a flat stretch 120 a disposed at the maximum diameter of shoulder portion 120 . The purpose of illustrating bottle 110 with flat stretch 120 a is to make it clear that a bottle in accordance with the present invention does not necessarily have to have a shoulder portion that is continuously arcuate in an axial direction in order to be within the scope of the present invention. It may assume a variety of configurations; however, in every instance it will have a maximum diameter.
[0023] It will be seen that in the bottle 110 , B is measured from a lower point on the shoulder portion 120 than in bottle 10 in accordance with the criteria that B is always measured from a point on the shoulder portion at its maximum diameter that is farthest from the neck finish to a point on the pinch portion at its minimum diameter that is closest to the neck finish. In this embodiment, of course, the neck finish of bottle 110 is denoted by the numeral 114 , and the pinch portion is denoted by numeral 122 .
[0024] FIG. 8 illustrates a third embodiment of the present invention comprising a bottle 210 wherein the shoulder portion 220 is continuously arcuate, but body portion 224 has a flat stretch 224 a at the maximum diameter of body portion 224 . Thus, bottle 210 illustrates that a bottle need not have a continuously arcuate body portion in order to fall within the scope of the present invention but may instead have a variety of configurations. In each instance, however, it will have a major diameter.
[0025] FIG. 9 illustrates a fourth embodiment of the present invention comprising a bottle 310 wherein shoulder portion 320 and body portion 324 are continuously axially arcuate but pinch portion 322 has a flat stretch 322 a . Obviously, even with flat stretch 322 a , pinch portion 322 still has a minimum diameter. In the illustrated embodiment, distance B is measured from a higher point on pinch portion 322 than with respect to pinch portions 22 , 122 , and 222 in the other embodiments because B is always measured from the point on the pinch portion at its minimum diameter that is closest to the neck finish ( 314 ).
[0026] FIG. 10 illustrates a fifth embodiment of the present invention comprising a bottle 410 having a flat stretch 420 a in the shoulder portion 420 , a flat stretch 422 a in pinch portion 422 , and a flat stretch 424 a in body portion 424 . Regardless, shoulder portion 420 still has a maximum diameter, pinch portion 422 still has a minimum diameter, and body portion 424 still has a major diameter. In this particular embodiment, distance B is measured between a lower point on shoulder portion 420 and a higher point on pinch portion 422 than in some of the previous embodiments in accordance with the requirement that distance B is always measured from a point on the shoulder portion at its maximum diameter that is farthest from the neck finish to a point on the pinch portion at its minimum diameter that is closest to the neck finish ( 414 ). Thus, bottle 410 illustrates that a bottle having a flat stretch or other configuration in the shoulder, pinch and body portions can still fall within the scope of the present invention.
[0027] Obviously, bottles having various combinations of non-continuously axially arcuate shoulder, pinch and body portions may still fall within the scope of the present invention. Moreover, the inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of their invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set out in the following claims. | A blown bottle constructed from synthetic resinous material is configured to facilitate the complete evacuation of viscous food product from the bottle using a conventional butter knife. | 1 |
BACKGROUND OF THE INVENTION
The present invention relates generally to locks and more particularly to a padlock with an alarm which sounds when someone tries to violate or tamper with the padlock.
Generally, a padlock comprises a body and a shackle having a pair of legs. The shackle is mounted for reciprocal movement relative to the body between a closed first position and an open second position. Located within the body is a latch for engaging one leg of the shackle when the shackle is in its closed position, and this prevents movement of the shackle to its open position. In order to move the shackle from its closed to its open position, the latch must be disengaged, and the padlock includes a lock mechanism operable to disengage the latch. The lock mechanism may be key operated or combination-operated in an authorized manner. The padlock is typically composed of a hard metal such as steel.
Padlocks are used for securing possessions or property to prevent theft or trespassing. It is not uncommon, however, for someone intent on theft or trespassing to tamper with the padlock in an attempt to open it in an unauthorized manner, either by severing the shackle or by forcing it into an open position. To deter a thief or the like from tampering with the padlock, it has been proposed to provide the padlock with an integral alarm system which sounds an alarm when the thief violates or tampers with the padlock. A padlock having an integral alarm system is disclosed in Stevens, U.S. Pat. No. 3,993,987. Such a system conventionally includes, in addition to the alarm sounding device, a battery for energizing the alarm sounding device and an electrical circuit and switches connecting the alarm sounding device to the battery and causing the alarm sounding device to operate when a violation occurs or an attempt is made to tamper with the padlock.
Because such an alarm system is powered by a battery, and because a battery can wear out, it is desirable to be able to test the battery to determine whether it still has sufficient power to operate the alarm. Provision for testing the battery is made in the system disclosed in the above-noted Stevens patent, but the test is complicated. First the lock mechanism must be opened with a key to open the shackle and then the lock mechanism must be closed with a key while the shackle is in its open position. Moreover, to shut off an alarm undergoing testing, either the lock mechanism must then be opened with a key or the shackle must be closed. No provision is made for automatic testing of the alarm so that, should one forget to proceed through the manipulative steps required in order to test the battery in the Stevens system, the battery could wear out without one knowing it. Furthermore, if the shackle is opened with a key, and the key is then removed, the Stevens alarm will sound, which is bothersome and otherwise undesirable.
Moreover, because all batteries eventually wear out and must be replaced, access must be provided to the battery within the padlock to permit removal and replacement of the battery. Such a provision, however, gives a thief the opportunity to gain access to the battery to remove it and deactivate the alarm. In Stevens there is no provision for sounding the alarm when a thief gains access to the battery.
SUMMARY OF THE INVENTION
The present invention constitutes a padlock with a tamper alarm which overcomes the deficiencies of the prior art described above. In accordance with the present invention, each time the shackle is moved between its open and closed positions in an authorized manner, the alarm is actuated momentarily, giving a short test beep or sound. Thus, the alarm and the battery are tested automatically each time the shackle is opened or closed in an authorized manner, and one need not remember intentionally to test the alarm to determine if it is still operative. In addition, a padlock in accordance with the present invention comprises structure for actuating the alarm whenever an attempt is made to remove the battery without first unlocking the shackle in an authorized manner. This structure effectively thwarts a thief who has gained access to the battery in an attempt to remove it.
In addition to the features described above, the padlock of the present invention comprises structure for actuating the alarm when an attempt is made forcibly to raise or to sever the shackle.
Other features and advantages are inherent in the structure claimed and disclosed or will become apparent to those skilled in the art from the following detailed description in conjunction with the accompanying diagrammatic drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a side elevation, in section, of a padlock with a tamper alarm in accordance with an embodiment of the present invention;
FIG. 2 is a bottom view of the padlock of FIG. 1;
FIG. 3 is a fragmentary view, partially in section, of one shackle leg for the padlock;
FIG. 4 is a fragmentary view, partially in section, illustrating a latch for the shackle leg;
FIG. 5 is a fragmentary sectional view taken along line 5--5 in FIG. 1;
FIG. 6 is a schematic diagram illustrating an electrical circuit for the alarm system in the padlock;
FIG. 7 is a fragmentary sectional view illustrating a part of the alarm system which operates when an attempt is made to remove the battery from the padlock without authorization; and
FIG. 8 is a plan view of a C-shaped ring employed in that part of the apparatus shown in FIG. 7.
DETAILED DESCRIPTION
Referring initially to FIGS. 1 and 2, indicated generally at 10 is a padlock body composed of a series of laminations 11, 11 held together by rivets 12, 12. Padlock body 10 has a pair of opposite ends 23, 24. Extending inwardly from body end 23 is an elongated channel 14 within which is normally located the long leg 15 of a shackle 16 having a short leg 17 which, when the shackle is in a locked position, is received within a channel 18 extending inwardly into padlock body 10 from end 23. Lining the outer portions of channels 14 and 18, respectively, are sleeves 20 and 21, both composed of electrically insulative material.
Shackle 16 is mounted for reciprocal movement relative to body 10 between a closed first position (FIG. 1), in which both shackle legs 15, 17 are received within their respective channels 14, 18 and an open position in which shackle short leg 17 is totally outside of its channel 18. Shackle long leg 15 remains within its channel 14 when the shackle is in an open position. However, long leg 15 does not extend as far inwardly into channel 14, when the shackle is in its open position, as long leg 15 does when the shackle is in its closed position illustrated in FIG. 1.
Located near the end 25 of shackle long leg 15, on opposite sides of long leg 15, are a pair of notches 26, 27 each for receiving a respective arm 28, 29 of a latch 30 (FIGS. 3 and 4).
Located adjacent latch 30 is a lock mechanism 31 operated by a key insertable into a key slot 32 located at end 24 of body 10 (FIG. 2). Lock mechanism 31 is of conventional construction normally found in padlocks and need not be described here. When lock mechanism 31 is operated by turning a key in slot 32, arms 28, 29 on latch 30 are spread apart to withdraw the arms from notches 26, 27 in long leg 15. The structure which spreads apart latch arms 28, 29 in response to the operation of lock mechanism 31 is conventional in nature and need not be described here. Structure of this nature is disclosed in Foote, U.S. Pat. No. 3,423,969 and the disclosure therein of such structure is incorporated herein by reference.
When latch 30 is disengaged from long shackle leg 15, the shackle is urged outwardly to its open position by structure now to be described. Located at end 25 of long leg 15 is a recess 34 within which is received a coil spring 35 mounted on a spring guide 36 located at the inner end 37 of channel 14. When shackle 16 is in the closed position indicated in FIG. 1, spring 35 normally urges shackle 16 towards its open position, but such movement is restrained by the engagement of long leg 15 with latch 30. Upon disengagement of latch 30 from long leg 15, coil spring 35 pushes shackle 16 to its open position. In that position, shackle short leg 17 is totally removed from within channel 18, and the free end 40 of short leg 17 is located totally outside of padlock body 10.
Located within body 10 is an alarm system which will now be described. Located inwardly of padlock body end 24 is a compartment 42 for receiving a battery 43. Communicating with compartment 42 is an entry 44 closed by a removable cap 45. Battery 43 has a positive pole 46 and a negative pole 47 located at respective opposite ends of the battery. Positive battery pole 46 is engaged by a resilient conductive element 48 connected by a wire 49 to a circuit board 50 located adjacent end 23 of padlock body 10.
Referring to FIGS. 1 and 7, negative battery pole 47 is engaged by a conductive element 52 extending from an inner conductive portion 53 of a disc-shaped member 54 having an outer contact portion 55 separated from inner conductive portion 53 by an insulative portion 56. A wire 57 connects inner conductive portion 53 of member 54 to circuit board 50 to ground the battery's negative pole 47. A wire 58 connects outer contact portion 55 to circuit board 50.
As noted above, entry 44 to battery compartment 42 is closed by a removable cap 45 which is externally threaded for engaging an internally threaded sleeve 61 which surrounds entry 44. Both sleeve 61 and cap 45 are composed of electrically insulative material.
Extending integrally inwardly from cap 45 is a stud 60 which, when cap 45 is threadedly engaged with sleeve 61 to close entry 44, engages member 54, pushing it inwardly into battery compartment 42. As previously noted, inner conductive portion 53 and its conductive element 52 engage negative battery pole 47, so that when stud 60 pushes inwardly on member 54, the latter pushes inwardly on battery 43. As battery 43 is pushed inwardly in compartment 42, positive battery pole 46 pushes inwardly against conductive element 48 the periphery of which engages against a spacing element 63 composed of non-conductive, resilient material, which compresses to accommodate the inward movement of battery 43. Spacing element 63 has an opening 64 through which extends wire 49 connecting conductive element 48 with circuit board 50.
Cap 45 is removable from threaded engagement with sleeve 61 in entry 44, by inserting a tool (not shown) into a slot 59 in the outer end of cap 45 (FIG. 2) and employing the tool to unscrew the cap. The outline of slot 59 corresponds to the cross-section of the tool. The tool is also used to screw cap 45 inwardly in entry 44 to the fully closed position for cap 45 shown in FIG. 1.
Removal of cap 45 from entry 44 eliminates the pressure of stud 60 pushing against member 54, and resilient spacing element 63 then expands to maintain conductive element 48 in engagement with positive battery pole 46 and to maintain negative battery pole 47 in engagement with conductive element 52. When cap 45 has been removed from entry 44, outward movement of member 54 through entry 44 is blocked by a C-shaped ring 65 located adjacent the inner end of entry 44.
When cap 45 has been removed from entry 44, and resilient spacing element 63 and conductive element 48 are in their fully expanded positions (not shown in FIG. 1), the distance between conductive element 48 and ring 65 is slightly less than the length of the battery from the tip of pole 46 to the tip of pole 47. Thus there is always some compressive force exerted against resilient spacing element 63 when battery 43 is in compartment 42 due to the condition described in the preceding sentence and to the interposition of element 54 between ring 65 and battery 43; and this is what keeps conductive elements 48 and 52 in contacting engagement with their respective battery poles 46, 47 when cap 45 has been removed.
C-shaped ring 65 is composed of resilient, electrically-conductive material. Referring to FIG. 7, located immediately adjacent C-shaped ring 65 and inwardly thereof in entry 44 is a ring 67 received within a groove 68 in internally threaded sleeve 61. C-shaped ring 65 is inserted into groove 68 by pinching together, e.g., with a needle-nose pliers, the perforate ends 74, 75 of ring 65 (FIG. 8) in a manner conventional to such rings. When ring ends 74, 75 are released, relieving the pinching on ring 65, the resiliency of the ring causes it to expand outwardly in groove 68, and inclined surface 69 of groove 68 cams ring 65 inwardly into close contacting, electrically-conductive engagement with ring 67 which is connected by a wire 70 to circuit board 50 (FIG. 1).
Ring 67 has an opening 72 through which may pass battery 43 for removal of the battery from compartment 42. Ring 65, located immediately outwardly of ring 67, has an opening 73 which is too small for battery 43 to pass through, thereby blocking removal of the battery. Battery 43 can only be removed if ring 65 is first removed from groove 68, and this is accomplished by pinching together the perforate ends 74, 75 of ring 65, in a conventional manner for such rings. Similarly, no replacement battery can be inserted into an empty compartment 42 if ring 65 previously has been inserted within groove 68.
Referring now to FIGS. 1 and 5, surrounding long shackle leg 15 is a first ring 78 composed of electrically insulative material. Ring 78 rests on a ledge 77 formed by one of the laminations 11, and ring 78 is in a stationary disposition relative to long shackle leg 15. Located on the outward-facing surface of ring 78 are a pair of ring-shaped conductors 79, 80 each of which is connected by a respective wire 81, 82 to circuit board 50. Conductors 79, 80 are spaced apart from each other and are electrically insulated from each other by ring 78.
Also disposed around long shackle leg 15 is a second ring 83 composed of electrically conductive material and movably mounted around long shackle leg 15 for movement toward and away from first ring 78. Second ring 83 is engaged by the inner end of a coil spring 84 having an outer end abutting against an overhanging ledge 85 formed by one of the laminations 11. Coil spring 84 normally urges second ring 83 into contact with first ring 78. When the two rings are in contact, second ring 83 electrically connects the two conductors 79, 80 on first ring 78. Coil spring 84, which acts on second ring 83 to urge it inwardly, is weaker than coil spring 35 which acts on shackle leg 15 to urge the leg outwardly when leg 15 is disengaged from latch 30.
Extending radially outwardly from long shackle leg 15 are a pair of aligned pins 87, 87 one of which is disposed on each side of leg 15. Upon disengagement of latch 30 from notches 26, 27 on shackle leg 15, shackle leg 15 is moved outwardly by its coil spring 35. When this occurs, pins 87, 87 engage second ring 83 and move ring 83 outwardly against the urging of its coil spring 84. This breaks the electrical connection between conductors 79 and 80 on ring 78.
As noted above, that portion of short shackle leg 17 adjacent its free end 40 moves through sleeve 21, and this sleeve has an internal groove 89 in which is mounted a conductor ring 90 located inwardly of free leg end 40. Located inwardly of conductor ring 90 is a conductor member 91 mounted on the outer end of a coil spring 92 in turn mounted on a spring guide 93 composed of electrically insulative material and mounted on a ledge 94 formed from a lamination 11.
Coil spring 92 is a conductive element and normally urges member 91 outwardly toward ring 90. A wire 96 attached to spring 92 connects conductor member 91 to circuit board 50, and a wire 95 connects conductor ring 90 to circuit board 50.
Extending outwardly from conductor member 91 is a stud 97 composed of electrically insulative material. Stud 91 extends outwardly through conductor ring 90 and abuts against free end 40 of short shackle leg 17 when the shackle is in its closed position (FIG. 1), and this holds conductor member 91 away from electrical contact with conductor ring 90, against the urging of coil spring 92. The distance between conductor member 91 and conductor ring 90, when the shackle is closed (as shown in FIG. 1) is much less than the distance traveled in an outward direction by free end 40 of short shackle leg 17, is much less than the distance travelled in an outward direction by pins 87, 87 to ring 83 and is much less than the distance travelled by any other part of the shackle, when the shackle moves from its closed to its open position. More particularly, outward movement of the shackle from its closed position (FIG. 1) is determined by ledge 85 which engages the outer end of compressible coil spring 84, thereby limiting outward movement of ring 83 under the urging of pins 87, 87 fixed on long shackle leg 15. Thus, the distance shackle 16 moves outwardly is no greater than the distance between ledge 85 and ring 83 when the shackle is closed minus the axial dimension of compressed coil spring 84.
Located between circuit board 50 and lock mechanism 31 is a transducer 100 for sounding an alarm. Located outwardly of circuit board 50 is a block 101 of electrically insulative, compressible material.
The electrical circuit for the alarm system is illustrated in FIG. 6 and comprises three switches indicated generally at 103, 104 and 105. First switch 103 is located in channel 18, adjacent free end 40 of short shackle leg 17 when the latter is in its closed position. Second switch 104 is located in channel 14 adjacent long shackle leg 15. Third switch 105 is located in entry 44 to battery compartment 42.
First switch 103 is closed when conductor member 91 is urged by coil spring 92 into contact with conductor ring 90, but first switch 103 is normally maintained in an open condition by the abutment of stud 97 against free end 40 of short shackle leg 17, thereby maintaining conductor member 91 out of contact with conductor ring 90.
Second switch 104 is closed when ring 83 electrically connects the two ring shaped conductors 79, 80 on ring 78. Second switch 104 is normally maintained in a closed position by the action of coil spring 84 pushing inwardly against ring 83.
Third switch 105 is closed when outer contact portion 55 on member 54 engages C-shaped ring 65. Third switch 105 is normally maintained in an open condition when cap 45 fully closes entry 44, causing stud 60 to push member 54 inwardly and out of contact with C-shaped ring 65.
Located on circuit board 50 are a pair of astable multivibrators 107, 108. The input to multivibrator 107 is connected to one end of second switch 104, by wire 82. The signal generated in multivibrator 107 is fed into multivibrator 108, through a set/reset input for the latter, where the signal from multivibrator 107 is integrated with the signal generated in multivibrator 108, and the resulting signal is then fed into transducer 100 to sound an alarm.
Electrical energy is conducted from battery 43 to multivibrators 107, 108 to generate respective wave forms therein, when second switch 104 is closed and either first switch 103 or third switch 105 is also closed. If both first and third switches 103, 105 are open while second switch 104 is closed, or if second switch 104 is open while either or both of switches 103 or 105 are closed, no energy will be conducted from battery 43 to multivibrators 107, 108.
The circuitry which makes up each of multivibrators 107, 108 is conventional and need not be disclosed here. Similarly, transducer 100 is of conventional construction and is readily available commercially. Typically, multivibrator 107 generates a square waveform 109 (FIG. 6) of about 4 hertz and multivibrator 108 generates a waveform 110 of about 4 kilohertz, and the two waveforms are integrated with the four kilohertz waveform being internal of the 4 hertz waveform (see 111).
When shackle 16 is moved between its open and closed positions, in either direction, in an authorized manner, the alarm is actuated momentarily as a test of its operativeness. The manner in which this occurs will now be described.
When shackle 16 is unlatched, both shackle legs 15, 17 move outwardly in response to the urging of coil spring 35. At the time outward movement of the shackle begins, second switch 104 is closed and remains closed until pins 87, 87 on long shackle leg 15 engage ring 83 to move ring 83 out of contact with ring 78. However, before this occurs, first switch 103 is closed.
More particularly, outward movement of short shackle leg 17 disengages free end 40 of shackle 17 from stud 97 allowing conductor member 91 to be urged by coil spring 92 into contact with conductor ring 90, and this occurs before pin 87 engages ring 83 around long shackle leg 15. This is because the distance between pins 87, 87 and ring 83 is greater than the distance between member 91 and ring 90, when the shackle is closed. With both switches 103 and 104 closed, an alarm is sounded, and the alarm continues to sound until second switch 104 is subsequently opened by the engagement of outwardly moving pins 87, 87 with ring 83.
Thus the alarm lasts from the time conductor member 91 engages conductor ring 90 until the time when pins 87, 87 engage ring 83, and this is only momentary. Therefore, when the padlock is opened in an authorized manner by inserting a key into key slot 32, and turning the same, a test signal of momentary duration is automatically sounded. A similar test signal of momentary duration is also automatically sounded when the padlock is closed.
More particularly, when shackle 16 is moved inwardly to close the padlock, pins 87, 87 move inwardly. As soon as pins 87, 87 move inwardly of ring 78, ring 83 is urged into engagement with ring 78 by coil spring 84 thereby closing second switch 104. Ring 83 engages ring 78 before free end 40 of short shackle leg 17 engages stud 97 to push the latter downwardly and disengage conductor member 91 from ring 89, to open first switch 103. Therefore, second switch 104 is closed shortly before first switch 103 is opened. With both switches 103 and 104 closed, the alarm sounds, and the alarm continues to sound until first switch 103 is opened. This occurs momentarily after second switch 104 is closed, but the time period when both switches are closed is enough to give a test signal of momentary duration.
First switch 103 is maintained open whenever short shackle leg 17 is in its closed position. Anything that causes short leg 17 to move from its closed to its open position while long shackle leg 15 is in its closed position (illustrated in FIG. 1), will close switch 103 and cause the alarm to sound. This will happen if short leg 17 is severed from long leg 15, e.g. by sawing or cutting shackle 16. Long leg 15 is the only part of the shackle engaged by latch 30, and the attachment of short leg 17 to long leg 15 is what holds short leg 17 in its closed position. When this attachment is severed, short leg 17 is no longer capable of restraining, through its engagement with stud 97, the upward urging of coil spring 92 against conductor member 91 which then moves into engagement with conductor ring 90 to close first switch 103.
The alarm will also sound if short leg 17 is pried or wrenched or otherwise raised up out of channel 18 while long leg 15 remains engaged by latch 30.
The manner in which the battery cap removal alarm sounds will now be described. When battery cap 45 threadedly engages internally-threaded sleeve 61 to close entry 44, stud 60 on cap 45 holds member 54 inwardly out of contact with C-shaped ring 65, to maintain third switch 105 in an open condition. When battery cap 45 is removed, stud 60 no longer constitutes an obstacle for the movement of member 54 in an outward direction toward C-shaped ring 65. Element 54 is urged outwardly toward C-shaped ring 65 by virtue of resilient spacing element 63 urging conductive element 48 outwardly against battery 43 which in turn urges member 54 outwardly until its outer contact portion engages C-shaped ring 65, thereby closing third switch 105. C-shaped ring 65 is connected through conductive ring 67 and wire 70 to normally closed second switch 104. Accordingly, closing third switch 105 connects the battery to the alarm generating circuit, sounding the alarm.
Battery cap 45 can be removed without sounding the alarm merely by first unlocking the padlock in an authorized manner with a key before removing cap 45. This disengages latch 30 from long leg 15 thereby causing long leg 15 to move outwardly within channel 14, disengaging ring 83 from conductors 79, 80 on ring 78, thereby opening second switch 104 before third switch 105 is closed by the removal of cap 45.
Set forth below in the following table is a summary of the effects produced by various combinations of switches in their open or closed position.
______________________________________Condition of SwitchFirst Switch, Second Switch, Third Switch,At Short At Long at entry toShackle Shackle BatteryLeg Leg Compartment Effect______________________________________Open Closed Open --*Closed Closed Open AlarmOpen Closed Closed AlarmClosed Open Closed --**Closed Closed/Open Open TestClosed Open/Closed Open TestClosed Closed Closed AlarmClosed Open Open --______________________________________ *normal condition **battery replacement condition
A battery 43 can be removed from compartment 42 for replacement by removing C-shaped ring 65 and pivoting element 54 on its wires 57, 58 to one side of entry 44, thereby allowing battery 43 to drop outwardly through entry 44. As noted above, ring 67 has an opening which is wide enough to permit battery 43 to pass therethrough while ring 65 has an opening too small for battery 43 to pass through, and therefore must be removed before battery 43 can be removed from compartment 42.
The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art. | A padlock contains a battery connected by electrical circuitry and switches to an alarm sounding device which sounds an alarm when someone attempts to force open or sever the lock shackle or when someone attempts to remove the battery in an unauthorized manner. A test signal of momentary duration is automatically sounded each time the lock is opened or closed in an authorized manner, and this indicates whether the alarm system is operative. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to V-blade snowplows, and more particularly to replaceable cutting edges of such plows.
2. Description of the Related Art
The most common type of snowplow has a straight blade which mounted to and extends across the full width of the front of a vehicle, such as a truck. In the simplest form, the angle of the blade with respect to the front of the vehicle is fixed at an angle so that snow being pushed by the blow is forced to one side. A more versatile straight plow enables blade to pivot with respect to the front of the vehicle so that the snow can be pushed to either side or straight ahead.
Another type of snowplow utilizes a V-blade which has two angled sections that meet at a forward edge and push the snow to both sides of the vehicle. This type of plow can incorporate a mechanism to alter the angle of the blades with respect to the each other. Typically, each blade is hinged to a center section of the plow frame and separate double-acting hydraulic cylinder and piston arrangements pivot the blade about the vertical hinge. This enables the two sections of the blade to be positioned in a standard “V” configuration that pushes the snow to each side, in a concave or scoop arrangement, or in a straight line that can be angled to either side of the vehicle.
In use, the bottom, or cutting, edge, of the blade scrapes against the surface being plowed. Usually that surface is very hard, often asphalt or concrete, which wears away the cutting edge. As a consequence the typical blade has a sacrificial cutting edge in the form of a metal plate that is removably mounted along the bottom edge. The edge plate, rather than the main section of the blade, is subjected to the wear during use. When most of the cutting edge plate has worn away it is replaced with a new one. It is more economical to replace the sacrificial cutting edge plate than the entire blade.
A characteristic of a V-blade is that the two blades are spaced apart under the center frame section which creates a gap through which some of the material being plowed can pass. This could leave in a rib of snow down the center of the area being plowed. To prevent this from occurring, prior blades spanned the gap with a flat rubber belt that was bolted to the cutting edges of each blade extending in front of the hinge on the center section. This belt flexed and stretched as the angle of the two blades changed. U.S. Pat. No. 6,108,946 describes an alternative solution that employs a semi-conical, solid catcher block beneath the center section of the V-blades. The catcher block closed the gap between the blade and its conical shape allowed the two sections to pivot without opening a gap. However the semi-conical catcher wore at a different rate than the cutting edges and had to be replaced at a different time. Furthermore, the solid block of material did not yield when struck by an object, such as a stone or other type of protrusion from the surface being plowed.
The outer tips of the blade also are subject to wear when plowing against a curb. In addition, significant force may be exerted on the edge of the blade upon striking a curb, which can adversely affect the blade hinge and the cylinder-piston arrangement used to pivot the blades. These forces, if significant, also can damage other components of the snowplow.
SUMMARY OF THE INVENTION
A V-blade plow has adjustable first and second blades, each with a bottom edge and an inner end that is rotatably connected to a pivot frame. The plow is provided with a cutting edge arrangement comprising first and second edge segments and a center edge segment there between. The first edge segment is removably attached to the first plow blade and projects downward below the bottom edge of the first plow blade. The second edge segment is removably attached to the second plow blade projecting below the bottom edge of the second plow blade. The center edge segment is mounted beneath the pivot frame and is attached to the first and second plow blades.
In a preferred embodiment of the cutting edge arrangement, the center edge segment is formed by a first wall that extends from the first edge segment under the pivot frame and by a second wall that extends from the second edge segment. The first and second walls meet beneath the pivot frame. The first wall may be integral with the first edge segment and the second wall may be integral with the second edge segment with a break between them. Alternatively, the first and second walls can be a single flexible piece of material attached to both the first and second edge segments. In yet another embodiment, the two walls are formed by a plurality of bristles, thereby creating an angled brush below the pivot frame.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a V-blade snowplow incorporating the present invention;
FIG. 2 is an isometric rendering of the lower part of the pivot frame of the snowplow blades illustrating the novel edge guard;
FIG. 3 depicts an outer end of the snowplow blade;
FIG. 4 is an isometric view of the lower portion of the pivot frame of the snowplow blades showing a second embodiment of an cutting edge according to the present invention;
FIG. 5 is an isometric representation of the underside of the pivot frame of the plow blade assembly in FIG. 4 ;
FIG. 6 is an isometric view of the lower portion of the pivot frame of the snowplow blade showing a third embodiment of a cutting edge; and
FIG. 7 is an isometric view of a fourth embodiment of a cutting edge.
DETAILED DESCRIPTION OF THE INVENTION
Although the present invention is being described in the context of a snowplow, the inventive concepts can be applied to V-blade plows for pushing other materials, such as earth, gravel and the like.
With initial reference to FIG. 1 , a snowplow 10 comprises a blade assembly 12 that has a first, or left, blade 14 and a second, or right, blade 16 moveably joined at their inner ends to a pivot frame 18 by a shared hinge 20 . Both blades 14 and 16 is able to pivot about the hinge axis 17 so that the blade assembly 12 can have a V configuration, as illustrated, or an inverse V in which the outer ends of each blade project forward of the pivot frame 18 to form a concave blade, or scoop. Alternatively, the first and second blades 14 and 16 can be aligned as a straight blade that can be rotated left or right about the pivot frame 18 . A hydraulic cylinder and piston assembly 21 is coupled between the pivot frame 18 and the second blade 16 to rotate that blade about the hinge 20 . Although not visible in the drawings, another hydraulic cylinder and piston assembly is coupled between the pivot frame 18 and the first blade 14 to provide pivoting motion there between.
The pivot frame 18 is secured to a push frame 22 which extends in a generally horizontal rearward direction from the bottom portion of the pivot frame. The end of the push frame 22 that is remote from the blade assembly 12 is coupled to a vehicle mount 24 in a manner that allows the push frame 22 to pivot about a horizontal axis. That pivot connection permits the push frame and blade assembly 12 to be raised and lowered with respect to the ground. A lift cylinder and piston assembly 26 extends between the push frame 22 and the vehicle mount 24 for that movement.
A hydraulic pump and motor 28 and a conventional hydraulic fluid reservoir are mounted on the push frame 22 . The motor of the pump is powered by electricity from the vehicle to which the snowplow is attached. Separate electrically operated control valves and hoses couple the pump and motor 28 to the different hydraulic cylinder and piston assemblies 21 and 26 in a conventional manner. A standard control panel is provided within the cab of the vehicle and has switches that enable the driver to independently operate each of the cylinders to pivot the first and second blades 14 and 16 and raise and lower the entire blade assembly 12 .
The vehicle mount 24 has couplings 30 and 32 on opposite sides for detachably engaging a support that is secured to the frame of the vehicle. Any of several well known mounting mechanisms can be provided for this purpose.
A cutting edge 38 is mounted along the lower regions of the front surface of the first and second blades 14 and 16 projecting below the bottom edge of the blades. The cutting edge 38 can be made of a rigid material, such as metal or a hard plastic, or a flexible material, such as polyurethane, plastic or a relatively hard rubber. With additional reference to FIG. 2 , the cutting edge 38 has an elongated first segment 40 that is bolted or otherwise attached to the lower region of the first blade 14 and an elongated second segment 42 is bolted to the lower region of the second blade 16 . The cutting edge 38 further includes a center segment 43 underneath the pivot frame 18 and formed by two center walls 44 and 46 . Specifically, the first segment 40 bends inwardly into the first center wall 44 that extends under the pivot frame 18 , and the second segment 42 bends inward forming the second center wall 46 which also projects under the pivot frame. The bend at the interface between the elongated segment 40 or 42 and the associated center wall 44 or 46 provides a smooth contour to the material being pushed by the plow. If a semi-rigid, yet flexible material is used, the center walls 44 and 46 are able to flex and allow an obstruction to pass under the pivot frame 18 . The interior remote ends of the two center walls 44 and 46 meet in an abutting manner at an interior vertical seam 48 that is aligned with the axis of the hinge 20 . Therefore, as the first and second blades 14 and 16 rotate about the hinge 20 the interior remote ends of the first and second center walls 44 and 46 remain abutting so that a gap is not created through which the material being plowed may pass.
By using a flexible material, the entire cutting edge 38 alternatively can be formed as a single piece. In this case, the first and second center walls 44 and 46 are joined at the seam 48 with the material providing a flexible joint between those walls which bends as the blades rotate about the hinge 20 .
The entire cutting edge 38 wears at the same rate, and thus, does not employ separate pieces of various sizes and materials which wear at different rates and may have to be replaced at different times.
With reference to FIG. 3 , the cutting edge 38 also protects the outside end of each blade 14 and 16 from damage due to striking a curb or other object extending upward from the surface being plowed. Specifically, the cutting edge 38 extends past the outer end 47 of the first blade 14 , curving into a rearwardly projecting side section 49 that is spaced from the vertical end. Thus, the side section 49 will rub against a curb and preventing wear from occurring on the outer end 47 of the first blade 14 on the left side of the snowplow 10 . Also, the flexible nature of the cutting edge 38 , enables this side section 49 to absorb some of the impact force resulting from striking a curb or other object and does not transfer that force through the first blade 14 into other components of the snowplow 10 . It should be noted that the outside edge 45 of the second blade 16 is similarly protected by the wrap-around end segment of the cutting edge 38 .
FIGS. 4 and 5 depict a second embodiment of a snowplow cutting edge 50 that comprises three separate pieces: elongated first and second segments 51 and 52 and a V-shaped center segment 54 . One of the first and second segments 51 or 52 is bolted or otherwise attached to the bottom portion of one of the two blades 14 and 16 in much the same manner as conventional cutting edges attached to existing blades. The V-shaped center edge segment 54 comprises a pair of walls 56 and 57 projecting at an angle from one another and terminating at a tapered edge that abuts the inside surface of two elongated edge segments 51 and 52 . That abutting relationship inhibits the material being plowed from passing between hose elongated sections. Preferably the walls 56 and 57 are formed by a single piece of material, such as polyurethane, plastic or a relatively hard rubber, but could be separate pieces in which case they could also be made of metal. The separate elongated first and second segments 51 and 52 may be made of the same material or metal. However, all the pieces of the cutting edge 50 will wear at the same rate if they are all made of the same material.
With specific reference to FIG. 5 , the center edge segment 54 has a mounting bracket 58 or 59 extending from the inside surfaces of the each wall 56 or 57 , respectively. The mounting brackets 58 and 59 are attached by machine screws or other fasteners to the bottom edges of the first and second blades 14 and 16 , respectively, thereby securing the center edge segment 54 beneath the pivot frame 18 of the snowplow blade assembly 12 . The two walls 56 and 57 the center edge segment 54 is made of a single piece of material that is formed at an angle. This material is flexible so that the pivot frame can bend at the interface between the two walls when one or both of the two blades 14 and 16 pivots about the hinge 20 .
With reference to FIG. 6 a variation of a three-piece cutting edge 60 has individual, elongated first and second segments 61 or 62 attached to the bottom portion of the two blades 14 and 16 . A separate V-shaped center edge segment 64 comprises has a pair of angled walls 65 and 66 located beneath the pivot frame 18 in an orientation identical to that of walls 56 and 57 in FIGS. 4 and 5 . However, walls 65 and 66 are each formed by a linear array of relatively stiff bristles 68 , thus forming a brush beneath the pivot frame 18 . That brush may comprises several rows of bristles 68 one behind the other. Each bristle 68 may be a thin rod or ribbon of stiff plastic material, for example. The upper ends of the bristles are mounted in a bracket that is attached to the blades 14 and 16 in the same manner as the walls 56 and 57 of the center edge segment 54 in FIG. 5 .
Referring to FIG. 7 , another version of a cutting edge 70 according to the present invention, utilizes separate elongated first and second segments 72 and 74 that are bolted or otherwise attached to the bottom portions of the first and second blades 14 and 16 respectively. A center cutting edge segment in the form of a conical brush 76 is mounted beneath the pivot frame 18 of the blade assembly 12 . The conical brush 76 comprises a plurality of relatively stiff bristles 78 extending at an angle that projects outward from the pivot frame 18 to form the conical shape. Each bristle may comprise a thin rod or ribbon of stiff plastic material, for example. The brush may comprise a single circular array of bristles, or several concentric arrays, depending upon the stiffness of the bristles in resisting the material being plowed from passing between the two blades 14 and 16 . The conical brush 76 has increased durability and resistance to impact with obstructions as compared to a solid center edge.
The foregoing description was primarily directed to a preferred embodiment of the invention. Although some attention was given to various alternatives within the scope of the invention, it is anticipated that one skilled in the art will likely realize additional alternatives that are now apparent from disclosure of embodiments of the invention. Accordingly, the scope of the invention should be determined from the following claims and not limited by the above disclosure. | A V-blade plow has adjustable first and second blades, each with an inner end that is rotatably connected to a pivot frame. The plow is provided with a cutting edge arrangement comprising first and second edge segments and a center edge segment there between. The first edge segment is removably attached to the first plow blade and projects downward below the bottom edge of the first plow blade. The second edge segment is removably attached to the second plow blade projecting below the bottom edge of the second plow blade. The center edge segment is mounted beneath the pivot frame and is attached to the first and second plow blades to prevent the material being plowed from passing beneath the pivot frame between the blades. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for forming a circuit pattern and, more particularly, to a pattern forming apparatus using a μ-STM and a method of forming a circuit pattern using the same.
2. Description of the Related Art
In the manufacture of large scale integrated circuits (LSI circuits) and the like, the step of forming various types of thin-film patterns such as a metal thin-film pattern as a wiring pattern is very important. Photolithography has been widely used for the formation of these patterns. In photolithography, a photosensitive resin film is exposed with ultraviolet rays, X-rays, an electron beam, or the like, and is developed to form a resin pattern having a predetermined plane shape. A semiconductor layer or a metal thin film on which the resin pattern has been formed is then selectively etched by using this resin pattern as a mask so as to be processed into a desired pattern. That is, a pattern forming method by photolithography is an indirect method via the resin pattern formation.
On the other hand, a pattern forming method employing the following direct writing method is also known. In this method, an electron beam or an ion beam is radiated onto a substrate in an atmosphere of, e.g., a gaseous organometallic compound. With this operation, the organometallic compound is decomposed, and free metal particles are deposited on the irradiated portion of the substrate. Therefore, by scanning an electron beam or an ion beam, a metal thin-film pattern is formed on the substrate.
Currently, a pattern having a line width of 100 nm can be formed by these techniques. However, in order to increase the integration density of an LSI circuit, elements must be further miniaturized. In order to miniaturize elements, a patterning technique with a higher resolution is indispensable. Under the circumstances, studies for achieving higher fineness and precision have been made. For example, a direct writing method and lithography based on the principle of a scanning tunneling microscope (to be referred to as an STM hereinafter) have been proposed.
An STM and a pattern forming method based thereon will be described below.
An STM is designed to scanning-microscopically observe the arrangement of atoms on a surface of a solid substance by using a free electron wave (tunnel current) penetrating through the surface due to a tunnel effect. Of controllable waves, a free electron wave has the shortest wavelength, which is equal to about the interatomic distance in a solid substance. Therefore, by applying the principle of an STM to lithography or the like, a finer pattern than that obtained by a conventional method can be formed.
FIGS. 1A and 1B show a direct writing method based on the principle of an STM. Referring to FIG. 1A, reference numeral 1 denotes a substrate having a surface on which a pattern is to be formed; and 2, a needle-like chip electrode for flowing a tunnel current. The substrate 1 is placed in a gas atmosphere of an organometallic compound, and the chip electrode 2 is arranged near the surface of the substrate 1. When a tunnel current J T is caused to flow between the chip electrode 2 and the substrate 1, the organometallic compound adsorbed on the substrate surface is dissociated by the energy of the current, and the free metal is deposited as metal particles 3 on the surface of the substrate 1. Therefore, by scanning the chip electrode 2 in the direction indicated by an arrow as shown in FIG. 1B, a metal thin-film pattern can be formed on the surface of the substrate 1.
In addition to the direct writing method shown in FIGS. 1A and 1B, lithography using a tunnel current can be performed in a similar manner. In this case, a lift-off technique is normally used instead of selective etching.
In the pattern forming method using the chip electrode 2, the highest resolution can be obtained by using a tunnel current, as described above. However, this method may be performed by using a current in a field emission region which has a higher energy than a tunnel current. Especially, in pattern formation by lithography, a current in a field emission region is preferably used. In a direct writing method using a current in a field emission region, it is considered that a local plasma formed by field emission contributes to the deposition of metal particles.
In order to form a micropattern such as an LSI wiring pattern by a method using the above-described STM, the chip electrode 2 is required to be greatly reduced in size and to be scanned within a predetermined micro-area. For this reason, by applying an LSI process, a micro chip electrode is formed on a distal end of a cantilever which has 5 μm of thickness and is formed within a region of 1 mm×5 μm. In the following description, the device including such micro chip electrode designed to be scanned will be called a "μ-STM", regardless of whether a tunnel current or a current in a field emission region is used.
A known μ-STM is provided with an actuator having four bimorph structures arranged along the longitudinal direction of the actuator, each of the bimorph structures being used for scanning the chip electrode in the upward, downward, leftward or rightward direction.
Another known μ-STM of cantilever type is shown in FIGS. 2A, 2B, and 2C (disclosed in Third STM International Meeting).
Referring to FIG. 2A, reference numeral 4 denotes a substrate. A semiconductor substrate such as a silicon substrate is used as the substrate 4. X-direction actuators 5X and 5Y are arranged on the upper surface of the substrate 4. Both the actuators 5X and 5Y extend outward from a peripheral portion of the substrate 4. The distal ends of the actuators 5X and 5Y are integrated with each other, thereby forming a chip corner. A micro chip electrode 6 is formed upright on the surface of the chip corner. In addition, various wires 7X to 9X, 7Y to 9Y, and 10 are formed on the surface of the substrate 4.
FIG. 2B is a cross-sectional view of the actuators 5X and 5Y. As shown in FIG. 2B, each actuator is a multilayered member consisting of an SiO 2 layer 11, an Al layer 12, a piezoelectric layer 13, an Al layer 14, a piezoelectric layer 15, and an Al+Au layer 16. As a piezoelectric substance, ZnO, lead zirconium titanate (Pb(Zr-Ti)O 3 ), or the like is used. The Al layers 12 and 14 and the Au layer 16 constitute voltage applying electrodes. Voltages are applied to the piezoelectric layers 13 and 15 through these electrodes. Upon this voltage application, the piezoelectric layers 13 and 15 cause expansion and contraction deformation at a rate of about 240 Å /v. Therefore, the deformations of the actuators 5X and 5Y are adjusted by controlling voltages to be applied, thus scanning the micro chip electrode 6 within a predetermined small range, not only in X-direction but also in Y- or Z-direction.
FIG. 2C is a plan view showing a wiring of the cantilever type μ-STM. As shown in FIG. 2C, various wires are formed on the surface of the substrate 4. The wires 7X, 8X, and 9X are respectively connected to the electrodes 16, 14, and 12 of the actuator 5X. The wires 7Y, 8Y, and 9Y are respectively connected to the electrodes 16, 14, and 12 of the actuator 5Y. The wire 10 is connected to the micro chip electrode 6. In addition, terminals 17X to 19X, 17Y to 19Y, and 20 are respectively formed on the proximal ends of the wires.
The above-described cantilever type μ-STM is manufactured on the basis of an LSI process. More specifically, the actuators 5X and 5Y as multilayered members each consisting of the SiO 2 layer 11, the Al layer 12, the piezoelectric layer 13, the Al layer 14, the piezoelectric layer 15, and the Al+Au layer 16 are formed on a substrate 4 by using a technique such as CVD, sputtering, or PEP (photo-engraving process). In addition, the micro chip electrode 6 is formed. Thereafter, a portion of the substrate 4 is removed by etching so as to cause the actuators 5X and 5Y to protrude from the peripheral portion of the substrate 4, as shown in FIGS. 2A and 2C.
The micro chip electrode 6 is formed in the manner shown in FIGS. 3A, 3B, and 3C. More specifically, a spacer layer 21 consisting of a removable substance such as Cu, and a mask layer 22 consisting of Ti/W are formed on the piezoelectric layer 15 constituting each actuator. By performing PEP, an opening having a diameter of about 5μ is formed in the mask layer 22. The spacer layer 21 is then overetched by using the mask layer 22 as an etching mask, thus forming an undercut hole 23. As shown in FIG. 3B, the conical chip electrode 6 is formed in the undercut hole 23 by vacuum deposition of a metal such as Ta. Subsequently, the spacer layer 21 is etched to lift off the mask layer 22 and the Ta layer deposited thereon, as shown in FIG. 3C.
Currently, a pattern can be formed to have a line width on the order of 10 nm by employing the method using the μ-STM. However, for example, the following problems are posed when this method is applied to an LSI manufacturing process.
In the manufacture of LSI circuits, predetermined LSI circuits are respectively formed in a large number of LSI-chip regions on one wafer. If these LSI circuits are to be manufactured by a μ-STM having only one micro chip electrode, wiring patterns and the like must be sequentially formed on the large number of LSI-chip regions. Therefore, a very long period of time is required, and practical productivity cannot be obtained.
SUMMARY OF THE INVENTION
It is the first object of the present invention to provide a circuit pattern forming apparatus using a μ-STM which can simultaneously form wiring patterns and the like in a large number of LSI-chip regions on a semiconductor wafer.
It is the second object of the present invention to provide a circuit pattern forming method using the apparatus.
In order to achieve the first object, according to the present invention, there is provided an apparatus for forming a predetermined circuit pattern on a circuit substrate by using a μ-STM write head, the μ-STM write head comprising:
a write head substrate having a flat surface;
a plurality of micro chip electrodes formed upright on the fat surface of the write head substrate and constituting a μ-STM, a level of a distal end of each of the chip electrodes being set to be constant; and
scanning means for scanning the micro chip electrodes on the circuit substrate by moving the micro chip electrodes and the circuit substrate relative to each other in two-dimensional directions.
In order to achieve the second object, according to the present invention, there is provided a method of forming a plurality of circuit patterns on a circuit substrate by direct writing, comprising the steps of:
positioning a write head according to the present invention and the circuit substrate to be close to each other; and
applying a bias voltage to micro chip electrodes of the write head in an atmosphere of a gaseous organometallic compound while moving the micro chip electrodes and the circuit substrate relative to each other in two-dimensional directions so as to dissociate the organometallic compound and liberate metal particles, and depositing the metal particles on the circuit substrate.
The second object can be achieved by a method of forming a plurality of circuit patterns on a circuit substrate by lithography, comprising the steps of:
positioning a write head according to the present invention and the circuit substrate having a resist film formed on a surface thereof to be close to each other:
writing a pattern on the resist film by applying a bias voltage to micro chip electrodes of the write head while moving the micro chip electrodes and the circuit substrate relative to each other in two-dimensional directions;
forming a desired mask pattern on the circuit substrate by developing the resist film on which the pattern is written;
depositing a desired circuit material film by CVD, on the circuit substrate having the mask pattern; and
removing the mask pattern and the circuit material film deposited thereon so as to leave the circuit material film on portions of the surface of the circuit substrate which are not covered with the mask pattern.
In addition, the second object can be achieved by a selective etching method using a mask pattern formed in the above-described manner.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.
FIGS. 1A and 1B are views for explaining a circuit pattern forming method based on the principle of an STM;
FIGS. 2A to 2C are views showing a conventional μ-STM employed in the present invention;
FIGS. 3A to 3C are views showing a known method of forming a micro chip electrode of a μ-STM;
FIGS. 4A to 6 are views showing a circuit pattern forming apparatus according to an embodiment of the present invention;
FIGS. 7 to 11B are views showing a circuit pattern forming method using the apparatus in FIGS. 4A to 6;
FIGS. 12A to 13B are views showing a circuit pattern forming apparatus according to another embodiment of the present invention; and
FIGS. 14 to 15B are views for explaining an apparatus used for the execution of the circuit pattern forming method of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in more detail below with reference to the preferred embodiments illustrated in the accompanying drawings.
FIGS. 4A to 4C show a circuit pattern forming apparatus according to an embodiment of the present invention. FIG. 4A is a plan view of a write head. FIG. 4B is a sectional view taken along a line B--B in FIG. 4A. FIG. 4C is an enlarged sectional view showing part of the write head.
Referring to FIGS. 4A to 4C, reference numeral 31 denotes a silicon wafer having a diameter of 4 inches which is used as a substrate of the write head. 500 μ-STMs 32 are formed on the wafer 31 in a matrix form. Each μ-STM 32 has the same arrangement as that described with reference to FIGS. 2A to 2C, and a detailed description thereof will be omitted. Note that the same reference numerals in FIGS. 4A to 4C denote the same parts as in FIGS. 2A to 2C. That is, reference numeral 4 denotes a substrate of a μ-STM; and 6, a micro chip electrode. Each μ-STM 32 is formed in a region of 3 mm×3 mm (9 m 2 ). Since the wafer 31 has a diameter of 4 inches, 500 μ-STMs can be arranged in an illustrated manner. As described above, the micro chip electrode 6 can be formed in a region of 1 mm 2 by using an LSI process. In addition, such a large number of μ-STMs 32 can be simultaneously formed. Note that the μ-STMs 32 are preferably arranged at a higher packing density.
Wiring shown in FIGS. 5 and 6 is formed in the 500 μ-STMs. More specifically, as shown in FIG. 5, scanning electrodes 12, 14, and 16 (see FIG. 2B) and the micro chip electrodes 6 for applying bias voltages are connected in parallel in units of rows. The μ-STMs 32 connected in units of rows are further connected in parallel in units of columns as shown in FIG. 6. One μ-STM 32 is formed in each region, although not shown in FIG. 6. Since all the μ-STMs are connected in parallel with each other, all the 500 μ-STMs 32 can be simultaneously scanned in the same direction by using only one driving power source. Therefore, 500 circuit patterns can be simultaneously written on a semiconductor wafer.
A method of forming circuit patterns by a direct writing method using the circuit pattern forming apparatus of the embodiment will be described below. Although a write operation of only μ-STM 32 will be described below, all the 500 μ-STMs operate in the same manner.
As shown in FIG. 7, the μ-STM 32 and a semiconductor wafer 1 are placed in a dimethyl cadmium gas atmosphere, and are fixed at a distance of several nm from each other. When a positive bias voltage of about 12 V is applied to the chip electrode 6 in this state, a tunnel current or a field-emission current (in this case, field-emission electrons) flows. Dimethyl cadmium is then dissociated by the electron beam, and Cd is deposited on the semiconductor wafer 1. Therefore, by driving actuators 5X and 5Y (see FIG. 2), Cd particles can be caused to be deposited in arbitrary points, and an arbitrary pattern can be formed.
FIGS. 8 to 10 show such a pattern forming method in detail. More specifically, if a bias voltage is applied to the chip electrode 6, writing is performed at a corresponding position. If no bias voltage is applied to it, writing is not performed at a corresponding position. Therefore, if the first row is scanned as indicated by an arrow in FIG. 8A, while a bias voltage is applied as shown in FIG. 8B, Cd particles can be caused to be deposited in only the positions where the bias voltage is ON so as to form a dot pattern. When the second and third rows are subsequently scanned as shown in FIGS. 9A to 10B, a Cd pattern shown in FIG. 10A can be written on the wafer 1. Note that one dot has a size of 10 nm×10 nm. Hence, a micro circuit pattern having a line width of 10 nm can be formed.
If a micropattern having a line width of 10 nm can be formed, a conventional LSI circuit which is formed on an LSI-chip region of 1 cm×1 cm by using a pattern forming technique for a line width of 1 μm can be integrated in a region of 100μ×100μ, as shown in FIG. 11A. However, the scanning range of the μ-STM using the actuators 5X and 5Y is about 10 μm×10 μm at best. A pattern must be written in a region 100 times larger than the scanning range. For this purpose, the LSI-chip region is divided into 100 areas, and patterns must be respectively formed in the areas and connected to each other by translating the μ-STM in parallel. More specifically, a pattern is formed in the first area as shown in FIG. 11A, and the μ-STM is then translated in parallel to form a pattern in the second area as shown in FIG. 11B. It is apparent that the pattern is formed in the second area so as to be connected to the pattern formed in the first area. In order to accurately connect the patterns which are formed in the respective areas in this manner, the μ-STM must be translated with high precision. For this purpose, the write head shown in FIG. 1 may be fixed on an X-Y stage incorporating a stepping motor.
A circuit pattern forming apparatus according to another embodiment of the present invention will be described below with reference to FIGS. 12 and 13.
In this embodiment, as shown in FIGS. 12A and 12B, a large number of micro chip electrodes 6 without actuators are arrayed on a surface of a substrate wafer 31. Each micro chip electrode 6 has a diameter of 100 Å or less and a height of about 2 μm. Such micro chip electrodes 6 can be formed by the method described with reference to FIGS. 3A to 3C. A large number of micro chip electrodes 6 are arranged into micro chip electrode units each consisting of 100 chip electrodes 6. The 100 micro chip electrodes 6 in each micro chip electrode unit are arranged to form a 10×10 matrix, as shown in FIG. 12C. The distance between the adjacent micro chip electrodes 6 is 10 μm. A bias voltage applying wire is formed for each micro chip electrode 6. Therefore, bias voltages can be independently applied to the respective micro chip electrodes 6.
As shown in FIG. 13A, the substrate wafer 31 on which the large number of micro chip electrodes 6 are formed is fixed on a support member 33. The support member 33 is coupled to a fixed frame 35 through X- and Y-direction actuators 34X and 34Y. FIG. 13B is a sectional view taken along line B--B in FIG. 13A.
As described above, in the write head of this embodiment, actuators are not arranged for each micro chip electrode 6. Therefore, the chip electrodes 6 cannot be independently scanned. However, since the actuators 34X and 34Y are arranged on the substrate wafer 31, all the chip electrodes 6 can be simultaneously scanned in the same direction by moving the substrate wafer 31. In this case, the relative positions of the chip electrodes 6 are not changed.
Another characteristic feature of this embodiment is that the 100 micro chip electrodes 6 are arranged in the form of a 10×10 matrix at intervals of 10 μm in each micro chip electrode unit, as shown in FIG. 12C. With this arrangement, a continuous pattern can be formed in an LSI-chip region shown in FIG. 11 without performing a translation operation using an X-Y stage as in the above embodiment.
More specifically, one micro chip electrode unit has the same area as that of the LSI-chip region shown in FIG. 11A, i.e., 100 μm×100 μm. Consequently, if the scan range of the chip electrode 6 by means of the actuators 34X and 34Y is 10 μm, any portion of the entire 100 μm×100 μm LSI-chip region falls within the scan range of a certain micro chip electrode unit. In addition, a bias voltage can be independently applied to the respective micro chip electrodes 6. If, therefore, direct writing is performed in the same manner as described with reference to FIG. 7, Cd particles can be deposited on arbitrary positions in the 100 μm×100 μm region by using the 100 micro chip electrodes 6 included in one micro chip electrode unit without performing a translation operation using an X-Y stage. That is, the 100 micro chip electrodes 6 simultaneously write different patterns and form a desired pattern in the 100 μm×100 μm region as a whole.
In the above-described embodiment, the 100 micro chip electrodes 6 constituting one micro chip electrode unit are formed in a 100 μm×100 μm region. Therefore, 500 micro chip electrodes units can be formed in the 4-inch substrate wafer 31. If the respective chip electrodes 6 are arranged in all the 500 micro chip electrode units in parallel with each other, and the same bias voltage is applied to all the respective chip electrodes 6, circuit patterns of the same number as that of the micro chip electrode units can be formed at once. In this case, 100 power source circuits (one in the preceding embodiment) for applying bias voltages are required, but the time required to write a pattern in an LSI-chip region can be reduced to 1/100.
In order to perform a write operation in an atmosphere of an organometallic gas such as a dimethyl cadmium gas as described above, the operation must be performed in a vacuum chamber. FIG. 14 shows an apparatus used for this operation. Referring to FIG. 14, reference numeral 40 denotes a vacuum chamber. The vacuum chamber 40 includes a mechanism for introducing an organometallic gas, and a mechanism for controlling a gas pressure to be 1 mTorr or less during an operation. An X-Y stage 41 is arranged in the vacuum chamber 40. The X-Y stage 41 can be translated within a small range and be positioned with high precision by an incorporated stepping motor. A support base 42 is arranged on the stage 41. A write head substrate 31 including a large number of micro chips 4 constituting a μ-STM is firmly fixed on the support base 42 so as not to be moved during the movement of the X-Y stage.
A circuit substrate convey mechanism 43 is arranged in the vacuum chamber 40. The mechanism 43 can be vertically moved and pivoted within a horizontal plane in the vacuum chamber 40. The mechanism 43 includes a Z stage 44 incorporating a stepping motor, and stacking type actuators 45a to 45c. A semiconductor wafer 1 on which patterns are to be formed is conveyed from a preliminary chamber into the vacuum chamber 40 by the substrate convey mechanism 43. When the mechanism 43 reaches a predetermined horizontal position where the center of the semiconductor wafer 1 coincides with that of the write head 31, it is lowered to bring the semiconductor wafer 1 to a position 1 mm away from the write head 31. Thereafter, the Z stage 44 arranged on the substrate convey mechanism 43 and the actuators 34a to 45c arranged on the Z stage 44 bring the semiconductor wafer 1 to a position (0.1 μm distant from the write head 31) where a tunnel current flows between the semiconductor wafer 1 and the write head 31. More specifically, the wafer 1 is brought to a position about 1 μm away from the write head 31 by the Z stage 44. The wafer 1 is then brought to a position 0.1 μm away from the write head 31 upon driving of the actuators 45a to 45c. After the wafer 1 is fixed at this position, pattern formation is performed by a direct writing operation using the above-described method.
When writing is to be performed, the semiconductor wafer 1 and the write head 31 must be positioned parallel to each other. If they ar not parallel to each other, a tunnel current does not flow at some portions, and portions on which no circuit pattern can be written or defective portions may appear. This problem can be solved by using the three actuators 45a to 45c in the following manner during positioning of the semiconductor wafer 1.
As shown in FIG. 15A, the actuator 45a is expanded first to cause a portion of the semiconductor wafer 1 to approach the micro chip electrode 6 up to the tunneling region. That the portion reaches the tunneling region can be confirmed by detecting a tunnel current from the chip electrode 6. As shown in FIG. 15B, the actuators 45b and 45c are sequentially expanded to cause the wafer 1 to approach the write head 31 until tunnel currents are detected from all the micro chip electrodes 6. In addition, the position of the semiconductor wafer 1 is adjusted to set variations in these tunnel currents to be 10% or less. This fine adjustment is preferably performed in the evacuated chamber 40. Even in an organometallic gas atmosphere, however, if a bias voltage between the micro chip electrode 6 and the semiconductor wafer 1 is set to be 100 mV or less, the position of the wafer 1 can be finely adjusted in the above-described manner without causing writing.
By using the apparatuses in the respective embodiments, a pattern can be formed not only by the above-described direct writing method but also by lithography.
When lithography is to be employed, writing is performed with respect to a mask material film formed on a surface of a semiconductor wafer 1 in the same manner as in the direct writing method. A mask pattern is then formed upon development. Thereafter, a desired pattern is formed by selective etching using this mask pattern or a lift-off method. A resist film, especially an LB film, is preferably used as a mask material film for this operation.
As has been described in detail above, according to the present invention, by using a write head on which a plurality of micro chip electrodes constituting a μ-STM are arranged, micro wiring patterns and the like can be simultaneously and efficiently formed on a large number of LSI-chip regions on a semiconductor wafer.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative devices, and illustrated examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. | An apparatus for forming a predetermined circuit pattern on a circuit substrate by using a μ-STM write head, the μ-STM write head comprising a write head substrate having a flat surface, a plurality of micro chip electrodes formed upright on the flat surface of the write head substrate and constituting a μ-STM, a level of a distal end of each of the chip electrodes being set to be constant, and scanning means for scanning the micro chip electrodes on the circuit substrate by moving the micro chip electrodes and the circuit substrate relative to each other in two-dimensional directions. | 8 |
CROSS-REFERENCES TO RELATED APPLICATIONS
Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT
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REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX
Not Applicable.
BACKGROUND
Embodiments in this disclosure relate to removable jaws for movable and fixed vise jaw stations which are used to immobilize a work-piece.
BACKGROUND
Description of Related Art Including Information Disclosed Under 37 CFR 1.97 AND 37 CFR 1.98
Embodiments of the present disclosure include vice jaws, termed claw jaws, which securely retain work-pieces otherwise known as “parts”, or stock material in a machine vise by creating indentations along the bottom edge of the stock material with sharp gripping teeth. Indentations are created by gripping the work-piece with sufficient force to set the dents, vise pressure is then released from the work-piece, and is re-clamped again with significantly less force for minimal distortion of the work-piece. Such claw jaws are useful in first or secondary machining operations in rapidly and repeatedly securing work-pieces for prototype through production manufacturing of precision machined work-pieces using manual, automatic, or computerized machining centers. Embodiments may secure flat, rectangular, irregular, and round or curved work-pieces. Work-pieces clamped using embodiments will resist machining forces exerted from any direction. This is important in manufacturing processes using vertical, horizontal, or multi-axis machining centers with 3, 4, or 5 axis capabilities that process work-pieces on 5 or more sides in a single clamping. A machined work-piece can be reloaded into the same set of jaws for re-machining or multiple operations with repeatability accuracy down to 0.001 of an inch. Only an additional 1/16 inch minimum of excess holding material is required to secure the work-piece in the vise, depending upon jaw and tooth configuration, step depth, and work-piece material condition. These claw jaws also incorporate an advantage of standard flat vise jaws by providing a precision ground flat front surface for clamping finished work-pieces without damaging previously machined surfaces, useful for secondary operations.
U.S. Pat. No. 4,928,938 to Ross discloses a clamping device which uses cylindrical rods to hold the work piece.
U.S. Pat. No. 6,152,435 to Snell discloses a vise with collet jaws designed to hold cylindrical work material having varying diameters.
U.S. Pat. No. 6,446,952 to Sheehy discloses a vise with removable jaws which are retained by a screw.
U.S. Pat. No. 6,530,567 to Lang discloses a clamping device with coupling elements on the clamping surface which interact with recesses in the work piece.
U.S. Pub. Pat. Applic. 2002/0056955 by Klabo discloses a vise jaw assembly with a step and gripping pads on the vise jaws
The discovered prior art do not provide the advantages of embodiments of the claw jaws which provide significant holding power while allowing the user to reduce clamping pressure exerted on the work-piece to minimize or eliminate work-piece distortion while maintaining the required holding force and requiring less excess work-piece holding material for securing the work-piece in a machine vise to enable reliable, accurate, and repeatable clamping. The prior art do not have sharp teeth for penetrating deep into the work-piece allowing for decreased clamping pressure after indentations are set. The prior art do not provide any additional clamping surfaces incorporated onto the same jaw; these claw jaws provide six clamping surfaces; four surfaces with an array of sharp teeth above a step to bite into or grip the bottom edge of a work-piece and two precision ground flat faces for clamping on finished machined surfaces or larger smooth surfaces of stock work-pieces. The prior art do not allow the user to reverse the jaw to additional clamping surfaces to use the entire range of the machine vise. The prior art do not allow the user to flip the jaws to expose a new or different tooth array or clamping surface. The prior art do not provide accessory holes integrated into both ends of the jaws to allow the user to position work stops in multiple places as deemed necessary to provide the repeatability accuracy.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.
BRIEF SUMMARY
The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tool, and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above described problems have been reduced or eliminated, while other embodiments are directed to other improvements.
Embodiments include jaws, termed claw jaws, which are attached to fixed jaw stations and movable jaw stations of machine vises which secure a work-piece for initial or further machining. Embodiments comprise a rectangular slab having flat front, rear, top, and bottom, and left and right surfaces. In addition, there is a work-piece gripper comprised of a step, a step floor, a step back relief, and an array of sharp teeth. The step is located at the intersection of the front or rear surfaces with the top or bottom surfaces of a claw jaw, respectively. An array of sharp teeth is located in front of the step back relief, the common centerline through the apex of the array of the teeth being aligned parallel to the top surface. The array comprises a multiplicity of adjacent pyramid-shaped teeth with a tangent radius connecting the left and right surfaces of adjacent teeth for strengthening the entire array. The front view of a single tooth in the array comprises four angular planes referred to as: lower, upper, left, and right surfaces that intersect to form the apex of the tooth which has a small tangent radius to strengthen the point. The lower surfaces of the teeth intersect the step floor at the undercut relief with a tangent radius to strengthen the entire array. The lower and upper surface of the teeth intersect at the apex of the teeth and lie on the same angular planes as the lower and upper surfaces of adjacent teeth.
In a second embodiment work-piece gripper comprised of a step, a step floor, a step back relief, and an array of sharp teeth having the appearance of a sine-wave like curve when viewed from the top. This appearance is created by an array of alternating tangential radii forming the curved shape of the teeth. This array of curved sharp teeth is located in front of the step back relief, the common centerline through the apex of the array of the teeth being aligned parallel to the top surface. The array comprises a multiplicity of adjacent curved teeth with tangent radii connecting the left and right surfaces of adjacent teeth for strengthening the entire array. The front view of a single tooth in the array comprises two angular planes referred to as: lower and upper and two curved edges referred to as: left and right; these surfaces intersect to form the apex of the tooth with the curved edges strengthening the clamping surface. The lower surfaces of the teeth intersect the step floor at the undercut relief with a tangent radius to strengthen the entire array. The lower and upper angular surface of the teeth intersect at the apex of the teeth and lie on the same angular planes as the lower and upper surfaces of adjacent teeth. The teeth have a sine wave like curved outline resulting from intersecting the left and right edges of tangential radii. The intersection of the upper, lower, left, and right surfaces form a sharp edge with a curved profile.
Embodiments also include third embodiment claw jaws which are attached to fixed jaw stations and movable jaw stations of a machine vise which secures a cylindrical work-piece for initial or further machining. Third embodiment claw jaws comprise a rectangular slab having flat front, rear, top, and bottom, and left and right surfaces with a partial cylindrical cavity at the intersection of the top and front surfaces. In addition, there is a work-piece gripper comprised a step, a step floor, a step back relief. The step is located within the partial cylindrical cavity at the intersection of the front surface with the top or bottom surfaces of a claw jaw, respectively. An array of sharp teeth is located near the top of the step back relief, the array being aligned parallel to the top or bottom surfaces. The array comprises a multiplicity of adjacent pyramid-shaped teeth as described for the first embodiment claw jaw or array comprises a multiplicity of adjacent sine-wave like curved teeth as described for the second embodiment claw jaw.
In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following descriptions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a flat or rectangular work-piece held by first embodiment claw jaws attached to the fixed jaw station and the movable jaw station of a machine vise.
FIG. 2 is a perspective view of a first embodiment claw jaw.
FIG. 3 is a front view of a first embodiment claw jaw.
FIG. 4 is an end view of a first embodiment claw jaw.
FIG. 5 is a top view of a first embodiment claw jaw.
FIG. 6 is a partial cross-section view taken at line 6 - 6 of FIG. 5 showing details of a first embodiment work-piece gripper.
FIG. 7 is a front view of a portion of an array of teeth showing three teeth on a first embodiment work-piece gripper.
FIG. 8 is a top view of a second embodiment work-piece gripper located on a first embodiment claw jaw.
FIG. 9 is a partial cross-section view taken at line 9 - 9 of FIG. 8 showing details of a second embodiment work-piece gripper.
FIG. 10 is a front view of a portion of an array of teeth showing three teeth on a second embodiment work-piece gripper.
FIG. 11 is a perspective view of a round work-piece held by third embodiment claw jaws attached to the fixed jaw station and the movable jaw station of a machine vise.
FIG. 12 is a perspective view of a third embodiment claw jaw.
FIG. 13 is a perspective view of a large flat or rectangular work-piece held by first embodiment claw jaws attached to the back of the fixed jaw station and to the back of the movable jaw station of a machine vise, showing the versatility and reversibility of the first and second embodiment claw jaws.
FIG. 14 is a perspective view of a flat or rectangular work-piece held by first embodiment claw jaws attached to the back of the fixed jaw station and to the front of the movable jaw station of a machine vise.
FIG. 15 is a perspective view of a flat or rectangular work-piece held by first embodiment claw jaws attached to the front of the fixed jaw station and to the back of the movable jaw station of a machine vise.
FIG. 16 is a perspective view of a flat or rectangular work-piece held internally by first embodiment claw jaws attached to the front of the fixed jaw station and to the back of the movable jaw station of a machine vise
DETAILED DESCRIPTION
FIG. 1 is a perspective view of a flat or rectangular work-piece held by first embodiment claw jaws attached to the fixed jaw station and the movable jaw station of a machine vise. Visible in FIG. 1 is a machine vise 90 , a fixed jaw station 94 , a movable jaw station 96 , a screw 97 for moving the movable jaw station, and a handle 98 for rotating the screw. First embodiment claw jaws 100 are attached to the fixed jaw station and the movable jaw station. A work-piece with flat surfaces 92 is retained between the claw jaws.
FIG. 2 is a perspective view of a first embodiment claw jaw 100 which has the general shape of a rectangular slab. Visible in FIG. 2 is the front surface 102 , top surface 104 , and right end surface 112 . Also indicated in FIG. 2 is the back surface 108 , bottom surface 106 , and left end surface 110 . Visible in FIG. 2 is the left attachment hole 116 and right attachment hole 117 . The attachment holes are used to securely attach a claw jaw to a fixed or movable jaw position in a machine vise using bolts or cap screws. Also visible in FIG. 2 is an upper threaded accessory hole 118 and a lower threaded accessory hole 119 . The accessory holes are used in conjunction with stops (not shown in FIG. 2 ) to allow repeatable securing of work-pieces in the jaws of the machine vise. For example, a washer which extends beyond the front surface 102 may be attached to the claw jaw using a fastener threaded into accessory hole 118 . Work-pieces may be reproducibly oriented in the vise by placing one surface of the work-piece abutting the extending portion of the washer. A front upper work-piece gripper 120 (shown in more detail in FIGS. 6 and 7 ) and a back upper work-piece gripper 122 are also visible. The step for a front lower work-piece gripper 121 and a back lower work-piece gripper 123 are also shown. In embodiments the front surface 102 and the back surface 108 are hardened, precision ground flat surfaces. Such surfaces are capable of clamping smooth stock or previously machined surfaces.
The purpose of multiple work-piece grippers on a single claw jaw is to allow reversibility to expose a new work-piece gripper when the teeth of the first-used gripper become worn and dulled through use, to introduce internal clamping applications using standard machine vises, and to utilize the entire working range of the machine vise using external and internal clamping applications, therefore increasing the size range of work pieces that may be gripped in the vise and allowing flexibility in clamping methods expanding the end users' machining capabilities. Alternatively the claw jaws allow versatility by incorporating one or more variations of embodiments of the work-piece gripper that may be on one claw jaw; making it possible to change the claw jaw to match the size or condition of the work-piece being retained by the vise.
FIG. 3 is a front view of a first embodiment claw jaw 100 . Visible in FIG. 3 is the front surface 102 , left end surface 110 , right end surface 112 , top surface 104 and bottom surface 106 . Also visible is the left attachment hole 116 , the right attachment hole 117 , upper front work-piece gripper 120 , and front lower work-piece gripper 121 .
FIG. 4 is an end view of a first embodiment claw jaw 100 . Visible in FIG. 4 is right end surface 112 , and the location of the front surface 102 , back surface 108 , top surface 104 , and bottom surface 106 is indicated. The upper threaded accessory hole 118 and lower threaded accessory hole 119 are shown. Also depicted are end views of the front upper work-piece gripper 120 , front lower work-piece gripper 121 , back upper work-piece gripper 122 , and back lower work-piece gripper 123 .
FIG. 5 is a top view of a first embodiment claw jaw 100 with first embodiment work-piece grippers 120 and 122 . Visible in FIG. 5 is the top surface 104 , front upper first embodiment work-piece gripper 120 , and rear upper first embodiment work-piece gripper 122 . Three components of the first embodiment work-piece gripper; the array of sharp pointed teeth 133 , the step floor 131 , and the step back relief 132 are also visible in FIG. 5 .
FIG. 6 is a partial cross-section view taken at line 6 - 6 of FIG. 5 showing details of a first embodiment work-piece gripper. First embodiment work-piece gripper 120 is located at the intersection of the front surface 102 and top surface 104 . The work-piece gripper is comprised of a step 130 , comprising a step floor 131 , and a step back relief 132 approximately perpendicular to the step floor, and an array of sharp pointed teeth 134 located in front of the step back relief 132 , and a common centerline through the apex of the array of pointed teeth 134 being aligned parallel to the top surface 104 .
An undercut relief 139 is located at the intersection of the step floor 131 and step back relief 132 . In embodiments the undercut relief 139 is a partial arc with a radius of approximately 0.015 of an inch, which serves to strengthen the intersection between the step floor 131 and tooth bottom surface 136 (shown in FIG. 7 ). The apex or point of the teeth 134 is located at a point closer to the top surface 104 than to the step floor 131 .
The width of the step floor 131 must be wide enough to insure the work-piece is supported by a pair of claw jaws. The width of the step floor 131 should be minimal in order to avoid the possibility of interfering with operations on the work-piece. For example, the step floor should not be so wide that drilling through the work-piece will involve drilling into the step floor. In embodiments, the step floor is approximately 0.154 of an inch and will vary depending upon specific application. In embodiments, the step floor is about 0.060 inch to about 0.300 inch wide.
FIG. 7 is a front view of a portion of an array of pointed teeth 133 showing three example pointed teeth 140 , 141 , 142 located on the step back relief 132 between the top surface 104 and the step floor 131 . The apex or point 134 of the teeth is closer to the top surface 104 than to the step floor 131 . The pointed teeth 140 , 141 , 142 approximate and may be thought of as pyramids each with an apex or point 134 , tooth top surface 135 , tooth bottom surface 136 , tooth left surface 137 , and tooth right surface 138 . In the pyramid model the surface area of the pointed tooth top surface 135 is less than or equal to the surface area of the tooth bottom surface 136 . In an array of pointed teeth of the first embodiment claw jaw the angle between the tooth right surface 138 of one tooth 140 and the tooth left surface 137 of adjacent tooth 141 approximates 90°. Although not shown in FIG. 7 , an undercut web is found at the intersection between adjacent teeth, for example at the intersection between the right surface 138 of tooth 140 and left surface 137 of tooth 141 . The undercut web is similar to the undercut relief 139 depicted in FIG. 6 .
FIG. 8 is a top view of second embodiment work-piece grippers 220 and 222 on a first embodiment claw jaw 100 . The second embodiment work-piece gripper differs from the first embodiment in the structure of the teeth. The teeth of the first embodiment viewed from the above are pointed; the teeth of the second embodiment viewed from above are curved.
Visible in FIG. 8 is the claw jaw top surface 106 , front upper second embodiment work-piece gripper 220 , and rear upper second embodiment work-piece gripper 222 . Two components of the second embodiment work-piece gripper, the array of curved teeth 233 and the step floor 231 are also visible in FIG. 8 .
FIG. 9 is a partial cross-section view taken at line 9 - 9 of FIG. 8 showing details of a second embodiment work piece work-piece gripper on a first embodiment claw jaw 100 . Second embodiment work-piece gripper 220 is located at the intersection of the front surface 102 and top surface 106 . The work-piece gripper is comprised of a step 230 , comprising a step floor 231 , and a step back relief 232 approximately perpendicular to the step floor, and an array of curved sharp teeth 234 located in front of the step back relief 232 , and a common centerline through the apex of the array of teeth 234 being aligned parallel to the top surface 106 . An undercut relief 239 is located at the intersection of the step floor 231 and step back relief 232 . In embodiments the undercut relief 239 is a partial arc with radius of approximately 0.015 of an inch, which serves to strengthen the intersection between step floor 231 and tooth bottom surface 236 (shown in FIG. 10 ). In embodiments the undercut relief is a partial arc with radius of approximately 0.002 inches to approximately 0.030 inches. The apex of the teeth 234 is located at a point closer to the top surface 106 than to the step floor 231 .
The width of the step floor 231 must be wide enough to insure the work-piece is supported by the claw jaw. The width of the step floor 231 should be minimal in order to avoid the possibility of interfering with operations on the work-piece. For example, the step floor should not be so wide that drilling through the work-piece will involve drilling into the step claw. In embodiments, the step floor is approximately 0.154 of an inch wide. In embodiments the step floor will very depending upon specific application. In embodiments the step floor is approximately 0.075 inch to approximately 0.300 inches wide.
FIG. 10 is a front view of a portion of an array of curved teeth 234 showing three example curved teeth 240 , 241 , 242 located on the step back relief 232 between the top surface 106 and the step floor 231 . The curved teeth 240 , 241 , and 242 have the appearance of a sine-wave like curve when viewed from the top surface of the claw jaw. The curved teeth 240 , 241 , 242 approximate and may be thought of pyramids each with a flat tooth top surface 235 with curved edges which form the appearance of an array of curved teeth when viewed from the top surface of the claw jaw. In curved tooth 240 , for example, the left curved edge 250 of the tooth top surface 235 is formed by the intersection of the tooth top surface 235 with the curved tooth left surface 237 , and the right curved edge 252 of the tooth top surface 235 is formed by the intersection of the tooth top surface 235 with the curved tooth left surface 238 . The tooth bottom surface 236 is angular but flat. In the pyramid model the surface area of the tooth top surface 235 is less than or equal to the surface area of the tooth bottom surface 236 . The apex 234 of each tooth is the point of intersection of the bottom and top angular surfaces and left and right curved edges of the tooth. The apex 234 is closer to the top 106 of the claw jaw than to the step floor 231 . Although not shown in FIG. 10 , an undercut web is found at the intersection between adjacent teeth, for example at the intersection between the right surface 238 of tooth 240 and left surface 237 of tooth 241 . The undercut web between the curved teeth is similar to the undercut relief 239 depicted in FIG. 9 , and serves to strengthen the area between the teeth of the entire array.
In embodiments the plane of the top surface of a tooth is at an angle of about 15° below the plane of the top surface of the claw jaw. This angle may vary from about 0° to about 45° below the plane of the top surface of the claw jaw. Relatively smaller angles are used with work-pieces of relatively softer material. Relatively larger angles are used with work-pieces of relatively harder material. For example, teeth with a relatively smaller angle of 15° would be damaged if used with a relatively hard work-piece, such as a work-piece made of tool steel. Claw jaws for use with such harder work-pieces would have an angle up to about 45°. These comments concerning the angle of the top surface of a tooth apply to any embodiments of the work-piece grippers.
FIG. 11 is a perspective view of a round or curved work-piece held by third embodiment claw jaws attached to the fixed jaw station and the movable jaw station of a machine vise. The elements of the machine vise 90 visible in FIG. 1 are also visible in FIG. 11 , a fixed jaw station 94 , a movable jaw station 96 , a screw 97 for moving the movable jaw station, and a handle 98 for rotating the screw. Third embodiment claw jaws 300 having a partial cylindrical cavity in the top surfaces are attached to the fixed jaw station and the movable jaw station. A work-piece with curved surfaces 93 is retained between the second embodiment claw jaws.
FIG. 12 is a perspective view of a third embodiment claw jaw 300 which has the general shape of a rectangular slab with a partial cylindrical cavity in the top surface. Visible in FIG. 12 is the front surface 302 , top surface 304 , partial cylindrical cavity 301 in the top surface, and right end surface 312 . Also indicated (but not visible) in FIG. 12 are the back surface 308 , bottom surface 306 , and left end surface 310 . Visible in FIG. 12 is the left attachment hole 316 and right attachment hole 317 . The attachment holes are used to securely attach a third embodiment claw jaw to a fixed or movable jaw position in a machine vise using bolts or cap screws. Also visible in FIG. 12 is an upper third embodiment work-piece gripper 320 (more detail on first embodiment work-piece grippers appears in FIGS. 6 , 7 , and 8 ) in the top surface 304 . Not visible in FIG. 12 is an optional lower work-piece gripper (more detail on second embodiment work-piece grippers appears in FIGS. 8 , 9 , and 10 ) located in the bottom surface 306 (not visible in FIG. 12 ). The upper and lower work-grippers may be of different dimensions for use with a variety of different size work-pieces, or the grippers may be of similar size. After one gripper is worn or damaged, extending the useful life of the claw jaw is possible by reversing or flipping the position of the claw jaw on the machine vise jaw stations, exposing a new set of grippers.
FIG. 13 is a perspective view of a flat work-piece held by first embodiment claw jaws attached to the back of the fixed jaw station and to the back of the movable jaw station of a machine vise. The elements of FIG. 13 are the same as the elements of FIG. 1 . A machine vise using the configuration in FIG. 13 is capable of securing relatively larger work-pieces compared to FIG. 1 . The claw jaws enable the user to cover the entire range of the machine vise by reversing the jaws from the standard inside clamping positions as shown in FIG. 1 , to the outside clamping position as shown in FIG. 13 , or any combination in between (entire range shown in FIG. 1 , FIG. 13 , FIG. 14 , & FIG. 15 ) to hold different size work-pieces utilizing the entire clamping range of the machine vise therefore expanding the end users' holding machining capabilities.
FIG. 14 is a perspective view of a flat work-piece held by first embodiment claw jaws attached to the back of the fixed jaw station and to the front of the movable jaw station of a machine vise. The elements of FIG. 14 are the same as the elements of FIG. 1 . A machine vise using the configuration in FIG. 14 is capable of securing relatively larger work-pieces compared to FIG. 1 . The claw jaws enable the user to cover the entire range of the machine vise by reversing the jaws from the standard inside clamping positions as shown in FIG. 1 , to a combination outside and inside clamping position as shown in FIG. 14 .
FIG. 15 is a perspective view of a flat work-piece held by first embodiment claw jaws attached to the front of the fixed jaw station and to the back of the movable jaw station of a machine vise. The elements of FIG. 15 are the same as the elements of FIG. 1 . A machine vise using the configuration in FIG. 15 is capable of securing relatively larger work-pieces compared to FIG. 1 . The claw jaws enable the user to cover the entire range of the machine vise by reversing the jaws from the standard inside clamping positions as shown in FIG. 1 , to a combination inside and outside clamping position as shown in FIG. 15 .
FIG. 16 is a perspective view of a cast or forged work-piece 91 clamped internally for initial machining or could also represent a previously machined work-piece 91 being re-clamped for further machining on a secondary operation held by first embodiment claw jaws attached to the front of the fixed jaw station and to the back of the movable jaw station of a machine vise (also shown in FIG. 15 ). The elements of FIG. 16 are the same as the elements of FIG. 1 . A machine vise using the configuration in FIG. 16 is capable of securing relatively larger work-pieces compared to FIG. 1 . The claw jaws also enable the user to clamp parts internally over the entire clamping range of the vise not just externally. Most other jaws are designed exclusively for external clamping applications only. Shown in FIG. 16 is another useful advantage of being able to reverse the claw jaws and shows the importance of having multiple grippers on one set of claw jaws. In FIG. 16 the work-piece being clamped on the inside, instead of the normal outside clamping method as shown in FIG. 1 , FIG. 13 , FIG. 14 , & FIG. 15 .
It is specifically contemplated that any embodiment work-piece gripper can be used with any embodiment claw jaw.
A pair of claw jaws are installed on a machine vise by attachment of one claw jaw to a fixed jaw station and the other to a movable jaw station. Any suitable reversible means of attachment may be used, such as socket head cap screws, bolts, or other fasteners which are inserted through counter bored holes in the claw jaw. The fasteners interact with threaded holes in the jaw stations. Threading fasteners through the attachment holes in the claw jaws into the jaw stations and tightening them will secure the jaws to the jaw stations of the machine vise.
The movable jaw station allows adjustability to make use of the entire clamping range of the vise. A work-piece stop is typically mounted to the side of the claw jaw and is used to locate work-pieces for repeatable setting within the machine vise for repetitive production applications.
In clamping a work-piece using a machine vise with installed claw jaws, the movable jaw station is rough adjusted to allow the work-piece to sit evenly on the step floor of both claw jaws. Generally, the work-piece will be loaded on the steps of the claw jaws and located against a work stop on either edge of the work-piece. The vise is then closed on the work-piece and clamped by the vise screw which moves the movable jaw station toward the stationary or fixed jaw station. The screw is activated by hand using a handle or hydraulically activated by a hand or foot switch. The operator clamps the vise with increasing pressure until the teeth of the claw jaws penetrate the work-piece sufficiently enough to form indentations in the work-piece. The clamping pressure required to set these indentations in the work-piece vary depending on the type and grade of the subject work-piece material. Generally, clamping pressure ranges from 50 to 100 foot pounds when applied by a manual torque wrench to a screw activated vise. Once the indentations are set into the work-piece, the clamping pressure can be significantly reduced to a much lower range to minimize clamping distortion of the work-piece. The clamping pressure is typically reduced between 5 to 50 foot pounds for machining of the work-piece, depending on the amount of allowable distortion of the finished work-piece.
The use of claw jaws typically result in indentations of approximately 0.050 of an inch deep. In many work-pieces, such as castings, forgings, or flame cut shapes such indentations are of little consequence and may be ignored. In other work-pieces, subsequent operations will remove the dented areas. Embodiment claw jaws with a hardened, precision ground flat front or back surface may be used to clamp smooth stock or smooth surfaces of previously machined stock. This allows the user to secure the stock for machine removal of the indentations without the need for changing the vise jaws.
Use of embodiment claw jaws allows greatly reduced clamping pressure during machining compared to conventional jaws while using significantly less excess material for clamping purposes. Without depending on this description of the operation of the claw jaws, it is believed the teeth of the claw jaws penetrate the work-piece and form recesses or indentation that project displaced material downward toward the step and into the undercut area, upward to the bottom surface of the teeth, and outward into the recessed web between the teeth above the step of the jaws. This displacement results in the work-piece being held with extreme force with very little clamping pressure compared to conventional methods. The use of these claw jaws provide the user with many benefits including: using less excess stock holding material, quick and secure clamping, work-piece distortion is kept to a minimum, work-piece accuracy improvements, elimination of preparatory operations, minimizing secondary operations, eliminating additional operations, and provides the user the ability to increase machining parameters to reduce cycle times and to increase profit margins.
Embodiment claw jaws hold the work-piece more firmly with much less distortion than other vise jaws while requiring less excess work-piece material for the vise to hold onto in order to secure the work-piece. Work-pieces thusly clamped will resist machining forces exerted from any direction. This is especially advantageous in manufacturing processes using vertical, horizontal, or multi-axis machining centers with 3, 4, or 5 axis capabilities which process parts on 5 or more sides in a single clamping. Once the work-piece has been machined and removed from the vise, it can also be reloaded into the same set of claw jaws with accuracies down to 0.001 of an inch, a capability very useful for re-machining on subsequent operations.
Embodiments of claw jaws are manufactured from any suitable hard, strong, ductile material which is harder than the work-piece material to be secured in the vise. Generally, case hardening or heat treatable carbon and alloy steels are used to manufacture claw jaws used for ductile materials such as aluminum, brass, plastics, and low carbon steels. Tool steels are used to manufacture claw jaws for use with medium and high carbon steels, alloy steels, stainless steels and tool steels up to 40 Hrc (Rockwell hardness scale). Embodiments are specifically contemplated which include carbide tipped teeth or replaceable tool steel teeth configurations to optimize the use of claw jaws with exotic work-piece materials and hydraulic vise applications.
The third embodiment claw jaws differ from the first embodiment in that the front side is not flat but has a partial cylindrical void. The third embodiment jaws are used to grip round or curved work-pieces.
While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions, and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions, and sub-combinations as are within their true spirit and scope. | An exemplary embodiment providing one or more improvements includes removable faces for jaws in machine vise which are able to grip a work-piece with great stability, accuracy, and reproducibility. Embodiments include multiple gripping features so the gripping surface easily can be renewed by demounting and reversing a worn face to a new face. Embodiments include the ability to of the claw jaws to be mounted on any fixed or movable vise station to use the entire clamping range of the machine vise. Embodiments are disclosed which are used with round or curved as well as flat work-pieces. Embodiments also include flat surfaced claw jaws which may be used to grip a work-piece for secondary machining to remove indentations from the work-piece. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60/217881, entitled “Accessing Active Directory via URL”, filed on Jul. 12, 2000.
FIELD OF THE INVENTION
[0002] The present invention relates generally to directory service access, and more particularly to accessing a directory service via a Hyper Text Transport Protocol (HTTP) Universal Resource Locator (URL).
BACKGROUND OF THE INVENTION
[0003] A directory service is a central point in a computer or a computer network where network services, security services, applications, and the like can inform other entities in the computer or network about their services, thus forming an integrated distributed computing environment. The current use of directory services may be classified into several categories. A “naming service” uses a directory as a source to locate an Internet host address or the location of a given server. A “user registry” stores information of all users in a system composed of a number of interconnected machines. The central repository of user information enables a system administrator to administer the distributed system as a single system image. Still another directory service is the MICROSOFT ACTIVE DIRECTORY directory service, a product of Microsoft Corp. of Redmond, Wash., which allows a system administrator to manage users, computers, printers, and other objects.
[0004] Conventional access to a directory service, such as a MICROSOFT ACTIVE DIRECTORY directory service is typically achieved by way of a Lightweight Directory Access Protocol (LDAP) query string. For example, a MICROSOFT ACTIVE DIRECTORY directory service can be accessed using LDAP application programming interfaces (APIs). However, using such APIs requires an intimate knowledge of the APIs and requires programming to call the APIs.
[0005] An MICROSOFT ACTIVE DIRECTORY directory service may also be accessed using ACTIVE DIRECTORY Service Interfaces (ADSI). However, using ADSI also requires programming.
[0006] Another method of accessing a directory service is the use of an LDAP query string formatted as a Universal Resource Locator (URL) query string (i.e., an LDAP URL) that is mapped to the directory service. The LDAP URL includes portions referencing a host port, a scope, an attribute, a query filter, and optional extension mechanisms. The LDAP URL host port portion references a particular directory server. The scope portion defines a search scope for the query. The search scope limits the objects that are searched during a request for information from a directory service. The attribute portion determines the attribute value to return based on the query. The query filter portion operates in a manner similar to commonly known filters, such as the wildcard “*”. The optional extension mechanisms are implemented with APIs. This method also assumes that LDAP protocol will be used to for communication.
[0007] Importantly, the use of an LDAP URL to access information in a directory service behind a firewall is limited for the reason that many directory service owners (corporations, typically) are unwilling to allow external access to LDAP ports on a firewall, mainly for reasons of security, resource utilization, and overhead issues. Nevertheless, such owners are more likely willing to allow external access to Hyper Text Transport Protocol (HTTP) ports on the firewall.
[0008] Therefore, there is a need for access to a directory service via an HTTP port. More particularly, a need exists for a system and method for accessing a directory service by way of an HTTP URL.
SUMMARY OF THE PRESENT INVENTION
[0009] The aforementioned need is satisfied by a system and method for accessing a directory service via an Hyper Text Transport Protocol (HTTP) Universal Resource Locator (URL).
[0010] In the system and method, information is retrieved from a directory service via an HTTP URL query string which is parsed by a diverting module into a plurality of portions. The diverting module constructs a directory service compatible query from the plurality of portions and submits the directory service compatible query to the directory service.
[0011] According to an aspect of the invention, data structure is implemented on a computer readable medium. The data structure used by the module may reside on a server. The data structure comprises includes an HTTP URL query string. The HTTP URL query string includes an HTTP portion representing that the query string is an HTTP URL query string, an anchor point portion representing an anchor point within the directory service for a search to be conducted based on the query string, and a path and query portion defining a search scope based on the anchor point for the search in the directory service.
[0012] According to another aspect of the present invention, a system retrieves information from a directory service into an access device via an HTTP URL query string. The system includes a server connected to the access device through an HTTP connection, the server for receiving the query string, for parsing the received query string into a friendly name portion, and for determining whether the friendly name portion is a member of a predetermined set of friendly names. The system further includes a diverting module for receiving the query string from the server if the friendly name portion is a member of the predetermined set of friendly names, for parsing the received query string, for constructing a directory service compatible query based on the parsed string, and for forwarding the directory service compatible query to the directory service.
[0013] The above-listed features, as well as other features, of the present invention will be more fully set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention is further described in the detailed description that follows, by reference to the noted drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:
[0015] FIG. 1 is a block diagram of an exemplary directory service with which the present invention may be employed;
[0016] FIG. 2 is a block diagram of a system that accepts an HTTP URL and formulates a directory service compatible query for the directory service of FIG. 1 in accordance with an embodiment of the present invention;
[0017] FIG. 3 is a block diagram of a data structure of an HTTP URL for being submitted to the system of FIG. 2 in accordance with an embodiment of the present invention;
[0018] FIG. 4 is a flow chart of an exemplary method employing the system of FIG. 2 and the data structure of FIG. 3 in accordance with an embodiment of the present invention; and
[0019] FIG. 5 is a block diagram representing a general purpose computer system in which aspects of the present invention and/or portions thereof may be incorporated.
DETAILED DESCRIPTION OF THE INVENTION
[0020] FIG. 5 and the following discussion are intended to provide a brief general description of a suitable computing environment in which the present invention and/or portions thereof may be implemented. Although not required, the invention is described in the general context of computer-executable instructions, such as program modules, being executed by a computer, such as a client workstation or a server. Generally, program modules include routines, programs, objects, components, data structures and the like that perform particular tasks or implement particular abstract data types. Moreover, it should be appreciated that the invention and/or portions thereof may be practiced with other computer system configurations, including hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers and the like. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.
[0021] As shown in FIG. 5 , an exemplary general purpose computing system includes a conventional personal computer 120 or the like, including a processing unit 121 , a system memory 122 , and a system bus 123 that couples various system components including the system memory to the processing unit 121 . The system bus 123 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a varietv of bus architectures. The system memory includes read-only memory (ROM) 124 and random access memory (RAM) 125 . A basic input/output system 126 (BIOS), containing the basic routines that help to transfer information between elements within the personal computer 120 , such as during start-up, is stored in ROM 124 .
[0022] The personal computer 120 may further include a hard disk drive 127 for reading from and writing to a hard disk (not shown), a magnetic disk drive 128 for reading from or writing to a removable magnetic disk 129 , and an optical disk drive 130 for reading from or writing to a removable optical disk 131 such as a CD-ROM or other optical media. The hard disk drive 127 , magnetic disk drive 128 , and optical disk drive 130 are connected to the system bus 123 by a hard disk drive interface 132 , a magnetic disk drive interface 133 , and an optical drive interface 134 , respectively. The drives and their associated computer-readable media provide non-volatile storage of computer readable instructions, data structures, program modules and other data for the personal computer 120 .
[0023] Although the exemplary environment described herein employs a hard disk, a removable magnetic disk 129 , and a removable optical disk 131 , it should be appreciated that other types of computer readable media which can store data that is accessible by a computer may also be used in the exemplary operating environment. Such other types of media include a magnetic cassette, a flash memory card, a digital video disk, a Bernoulli cartridge, a random access memory (RAM), a read-only memory (ROM), and the like.
[0024] A number of program modules may be stored on the hard disk, magnetic disk 129 , optical disk 131 , ROM 124 or RAM 125 , including an operating system 135 , one or more application programs 136 , other program modules 137 and program data 138 . A user may enter commands and information into the personal computer 120 through input devices such as a keyboard 140 and pointing device 142 . Other input devices (not shown) may include a microphone, joystick, game pad, satellite disk, scanner, or the like. These and other input devices are often connected to the processing unit 121 through a serial port interface 146 that is coupled to the system bus, but may be connected by other interfaces, such as a parallel port, game port, or universal serial bus (USB). A monitor 147 or other type of display device is also connected to the system bus 123 via an interface, such as a video adapter 148 . In addition to the monitor 147 , a personal computer typically includes other peripheral output devices (not shown), such as speakers and printers. The exemplary system of FIG. 12 also includes a host adapter 155 , a Small Computer System Interface (SCSI) bus 156 , and an external storage device 162 connected to the SCSI bus 156 .
[0025] The personal computer 120 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 149 . The remote computer 149 may be another personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the personal computer 120 , although only a memory storage device 150 has been illustrated in FIG. 12 . The logical connections depicted in FIG. 12 include a local area network (LAN) 151 and a wide area network (WAN) 152 . Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, and the Internet.
[0026] When used in a LAN networking environment, the personal computer 120 is connected to the LAN 151 through a network interface or adapter 153 . When used in a WAN networking environment, the personal computer 120 typically includes a modem 154 or other means for establishing communications over the wide area network 152 , such as the Internet. The modem 154 , which may be internal or external, is connected to the system bus 123 via the serial port interface 146 . In a networked environment, program modules depicted relative to the personal computer 120 , or portions thereof, may be stored in the remote memory storage device. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used.
[0027] Turning now to FIG. 1 , it is seen that such drawing represents an exemplary directory service hierarchy. The following discussion of the naming hierarchy in FIG. 1 is merely illustrative and is not intended to be limiting. As shown in FIG. 1 , the directory service 10 includes a number of objects, with each object represented by a unique name and all of the objects being organized into a hierarchical structure. Thus, for example, the object at the top of the hierarchical structure is named A, which is typically referred to as the “root”. Object A has two “children”, objects B and C, and objects B and C resides one level below the root and dependent from object A. Object B has two “children”, objects E and F, and objects E and F reside two levels below the root and dependent from object B. Object F has one “child”, object H, and object H resides three levels below the root and dependent from object F. A particular object thus may be a “parent” of one or more child objects. An object is considered a “parent” if it is located in a next higher level than a “child” object in the hierarchy and the child object depends from such parent object. Objects on the same level of the hierarchy, with the same parent are considered siblings. In this manner, a system administrator may organize objects into a hierarchical structure.
[0028] Each object is of a particular object class. For example, there may be a computer object class, a printer object class, and a user object class. As specific examples, object B may represent a printer and may be configured as a printer object class, object C may represent a computer and may be configured as a computer object class, and object E may represent a user and may be configured as a user object class. In this manner, a system administrator may organize objects by class in addition to a hierarchical structure.
[0029] Each object may contain attributes, and each attribute may contain a value associated with the attribute. For example, an attribute of a user class object may be a phone number. The value of the attribute may be set to a phone number of that particular user. In this manner, a system administrator may include information regarding objects in a directory service.
[0030] The directory service 10 hierarchy may be organized in any predefined manner, for example by the system administrator. Each object in the directory service is typically uniquely identified in the directory and uniquely named for a given parent. Additionally, some directory services, such as the MICROSOFT ACTIVE DIRECTORY include a UserPrincipalName attribute for user class objects. Typically, the UserPrincipalName attribute is set to a value of an e-mail address, for example, JohnSmith@microsoft.com.
[0031] Referring now to FIG. 2 , there is shown an exemplary system 11 for accessing the directory service 10 of FIG. 1 based on an HTTP URL query string in accordance with an embodiment of the present invention. As shown in FIG. 2 , the system 11 includes a server 25 and a diverting module 30 . As may be appreciated, the system 11 receives the HTTP URL query string from an access device 15 by way of an HTTP port 21 on a firewall 20 associated with the server 25 , and is coupled to the directory service by way of the diverting module 30 . In one embodiment, the server 25 comprises the diverting module 30 .
[0032] The access device 15 may be a web browser, a cellular phone, a net appliance, or any other device suitable for entering an HTTP URL that is to be delivered to the server 25 . Access devices 15 are generally known or should be apparent to the relevant public and therefore need not be described herein in any detail. Thus, the access device 15 may be any particular access device without departing from the spirit and scope of the present invention. In one embodiment, the access device 15 is a personal computer running a MICROSOFT INTERNET EXPLORER web browser, a product of Microsoft Corp. of Redmond, Wash., or the like.
[0033] The access device 15 may access the system 11 by an appropriate connection, including a direct connection, an Ethernet connection, an Intranet connection, an Internet connection, a dialup connection, or the like. As shown in FIG. 2 , the connection with the system 11 is achieved by way of the firewall 20 , so the access device 15 is presumably externally located with respect to the system 11 . Nevertheless, the access device 15 may also be internally located so that the firewall 20 is not necessary without departing from the spirit and scope of the present invention.
[0034] Server 25 and access device 15 can communicate with each other through the firewall 20 (if present) via any mutually agreeable protocol, such as HTTP, for example. Firewalls 20 and servers 25 are generally known or should be apparent to the relevant public and therefore need not be described herein in any detail. Thus, the firewall 20 may be any particular firewall and the server 25 may be any particular server without departing from the spirit and scope of the present invention. In one embodiment, the server 25 is an Internet Information Server (IIS).
[0035] The HTTP port 21 may represent any port through which HTTP communication is enabled. The HTTP port 21 may also represent the default port for communicating web pages with client browsers. In one embodiment, the access device 15 is connected to the server through an HTTP port 21 on the firewall 20 .
[0036] The firewall 20 is a security system (hardware and/or software) that isolates resources of the system 11 and beyond from objects outside of the system 11 . Isolated resources are characterized as inside the firewall, and external equipment is considered outside the firewall. Typically, the firewall 20 serves as a security enclosure around a private LAN of computers and associated peripherals. Generally, the firewall 20 allows for inside objects to request and receive connections to outside objects (e.g., for inside applications to access outside internet nodes, etc.) but prevents outside objects from originating similar connections unless otherwise determined to be allowable.
[0037] The directory service 10 is generally known or should be apparent to the relevant public and therefore need not be described herein in any detail. The directory service 10 may be any particular directory service without departing from the spirit and scope of the present invention. In one embodiment, the directory service 10 is the MICROSOFT ACTIVE DIRECTORY directory service. The directory service 10 is connected to the server 25 over a conventional data link, such as for example, an Ethernet connection or a direct connection from the server 25 .
[0038] Typically, a server such as the server 25 receives a query for the directory service 10 where such query is already in a form amenable to the directory service 10 . For example, where the directory service 10 can receive and process an LDAP query string, the server 25 would typically receive a query for the directory service 10 in the form of such LDAP query string.
[0039] Importantly, in the present invention, the server 25 receives a query for the directory service 10 where the query is in one form (e.g., an HTTP URL query string) and where the directory service 10 is expecting the query to be in another form (e.g., an LDAP query string). Accordingly, in one embodiment of the present invention, the system 11 includes the diverting module 30 for receiving the query string for the directory service 10 from the server 25 for reformatting the query string into a form amenable to the directory service 10 , and for sending the reformatted query string to the directory service 10 .
[0040] In particular, in an embodiment of the present invention, the diverting module 30 receives the query string from server 25 , parses the query string, forms the reformatted query string, and then sends the reformatted query string to the directory service 10 . Once the directory service 10 gathers appropriate information based on the received reformatted query string, such information is sent to the server 25 perhaps by way of the diverting module 30 . As may be appreciated either the server 25 or the diverting module 30 may format the information in a form amenable to the access device 15 . For example, the information may be formatted into a Hyper Text Markup Language (HTML) web page, eXtensible Markup Language (XML), or the like, to be displayed on the browser of the access device 15 .
[0041] In one embodiment of the present invention, the query string from the access device 15 is an HTTP URL query string having a particular data structure that may be appreciated by the diverting module 30 in the course of reformatting such HTTP URL query string into the form expected by the directory service 10 .
[0042] FIG. 3 shows a block diagram of such a data structure 35 in accordance with an embodiment of the present invention. As shown in FIG. 3 , the data structure 35 of the query string includes an HTTP portion 40 , a server name portion 45 , a friendly name portion 50 , a path and query portion 60 , and an optional parameters portion 65 . Thus, an exemplary HTTP URL query string may be given by:
http://servername/friendlyname/path-and-query?parameters
As may be appreciated, such HTTP URL query string is to be sent to the server 25 in the manner of a typical HTTP request sent to a typical HTTP server.
[0044] In one embodiment of the present invention, the server 25 behind the firewall 20 receives the HTTP URL query string by way of an HTTP port on the firewall 20 and recognizes that the request is to be diverted to the directory service 10 by way of the diverting module 30 . Such recognition may for example occur based on the server name portion 45 and/or the friendly name portion 50 of the query string, although other recognition methodologies may be employed without departing from the spirit and scope of the present invention.
[0045] Upon receiving the diverted query string, the diverting module 30 parses and deconstructs such HTTP URL query string into the various portions 50 - 65 , constructs the aforementioned reformatted query string, and then transmits same to the directory service 10 .
[0046] Portions 40 - 65 are discussed in turn as follows. The HTTP portion 40 contains information representing the beginning of an HTTP URL string. For example, the HTTP portion 40 may contain the string “http://”.
[0047] The server name portion 45 contains information representing any server name that can be resolved to an Internet Protocol (IP) address. The server name links the access device 15 to a server, such as server 25 . For example a server name portion 45 may be “microsoft.com”, which would map the access device 15 to the server 25 associated with the name “microsoft.com”.
[0048] The friendly name portion 50 contains information representing to the server 25 that the query string is to be diverted to the diverting module 30 for parsing. The friendly name may be any name that triggers the diverting module 30 to parse the query string as a request for information from the directory service 10 . In one embodiment, the server 25 compares the friendly name against a predetermined set of names. If the friendly name is included in the predetermined set of names, then the server 25 diverts the query string for parsing by the diverting module 30 . If not, then the query string is processed as a conventional query string by the server 25 . A friendly name is not necessary as a diverting mechanism, for example, a server 25 may be dedicated to directory service 10 .
[0049] In another embodiment, the diverting module 30 parses the query string and if the friendly name is not included in the predetermined set of names, then the diverting module 30 diverts the query string to the server 25 .
[0050] In one embodiment of the present invention, the friendly name portion 50 and the friendly name therein also anchors a search scope to a predetermined anchor point in the directory service 10 . The friendly name may also serve other purposes including improving query performance, filtering HTTP verbs, canonicalizing long naming, and limiting users to a subset of objects that are pertinent to their queries.
[0051] As may be appreciated, an anchor point is an object within the directory service 10 from which the search scope is defined. For example, in the directory service 10 of FIG. 1 , a partial query string of:
http://microsoft.com/consultants
maps to the server 25 with the name “microsoft.com”, and sets an anchor point, within a directory service 10 associated with the server 25 , according to a predetermined criteria associated with the friendly name “consultants”. For example, the anchor point for “consultants” may be set at object B, as shown in FIG. 1 . In one embodiment of the present invention, no searching takes place on objects higher in the directory service 10 than the anchor point. Here, then, with ‘consultants’ as the anchor point, the object A will not be included in the search scope. In this manner, a query can be limited to selected branches of the directory service 10 .
[0053] The path and query portion 55 contains information referencing the path to be searched and query options to further define the search scope. The path sub-portion of the path and query portion 55 defines the boundary or scope of the search scope with respect to the anchor point. The search scope may be defined to include the anchor point itself, to exclude the anchor point but to include one level below the anchor point, to include the anchor point and the entire subtree below the anchor point, or the like. The query sub-portion of the path and query portion 55 modifies the search with commonly known filters, such as a wildcard “*” and a slash “/”, as will be described further below.
[0054] In one embodiment of the present invention, a path and query of “/*” searches the children of the anchor point, a path of “/objectX/*” searches the children of objectX, wherein objectX is a child of the anchor point, and a path of “/objectX//” searches the subtree of objectX, wherein objectX is a child of the anchor point.
[0055] For example, and with respect to the directory service 10 of FIG. 1 , a partial query string of:
http://microsoft.com/consultants/*
searches the children of B, which are object E and object F. Likewise, a query string of:
http://microsoft.com/consultants/F/*
searches the children of F, which is object H. Similarly, a query string of:
http://microsoft.com/consultants//
searches the sub-tree of B, which includes object B, object E, object F, and object H, given that object B is the anchor point associated with ‘consultants’.
[0059] In one embodiment of the present invention, a search may be based on an attribute name by including a path and query of “attribute=attribute value”.
[0060] For example, and with respect to the directory service 10 of FIG. 1 , a partial query string of:
http://microsoft.com/consultants//givenName=John
searches the sub-tree of B, which includes object B, object E, object F, and object H. Additionally, the query sub-portion of “givenName=John” searches all objects within the search scope as described above, and searches for an attribute of “givenName” with a value of “John”.
[0062] Similarly, searches may be based on object class by including a query sub-portion of “.object class”. For example, a query sub-portion of “*.user” searches for all objects in the directory service with an object class of “user” within the defined search scope.
[0063] For example, and with respect to the directory service 10 of FIG. 1 , a partial query string of:
http://microsoft.com/consultants//*.user
searches the sub-tree of B, which includes object B, object E, object F, and object H. Additionally, the query sub-portion of “*.user” searches for all objects within the search scope as described above, and searches for all objects of object class “user”.
[0065] Additionally, a wildcard may be used in query portion. For example, a query string of:
http://microsoft.com/consultants//John*.user
searchers the sub-tree of B, which includes object B, object E, object F and object H. Additionally, the query sub-portion of “John*.user” searchers for all objects within the search scope as described above, and searches for all objects of object class “user” and with its object name starts with “John”.
[0067] The parameters portion 65 may contain information referencing optional parameters. Such optional parameters may, for example, modify default parameter values, such as PageSize, which specifies the page size to return, and TimeOut, which determines how long to wait for a response before timing out. Also, the parameters portion 65 may be used to request an attribute be returned to server 25 from the directory service 10 , as described in more detail below.
[0068] As discussed above, the HTTP URL request may be responded to by the system 25 with an HTML page. In addition, the response may be in an XML format. In one embodiment of the present invention, a parameter in the parameters portion 65 of the HTTP query string may be set to specify the type of response. For example, a parameter may be set to request a HTML format, or other form of documents. Optionally, the response may include error messages.
[0069] In one embodiment of the present invention, the parameters portion 65 contains information referencing an attribute value to be returned. For example, the parameters portion 65 may be specified as “?attr=attributename” in the HTTP query string. If a particular attribute value is to be returned, as triggered by the “?attr=” portion of the query string, the directory service 10 returns the value of the attribute. If no attribute is to be returned, the directory service 10 returns a default set of attributes for each object of the defined search, such as the URL, name, and class of the object. For example, a query string of:
http://microsoft.com/consultants/?attr=phonenumber,title
returns the value in the attribute phone number and title of object B, if such attribute exists for the object. Referring now to FIG. 4 , a method of operating the system 25 to access a directory service 10 is shown. As seen at step 200 , the access device 15 sends an HTTP URL query string to the server 25 . This step is similar to conventional server access via an HTTP URL query string. For example, the HTTP URL query string may be
http://microsoft.com/consultants//sn=Smith The query string is received at the http port 21 and firewall 20 and passes through to the server 25 as a conventional HTTP URL query string.
[0073] At step 205 , the server 25 detects that the query string is to be diverted to diverting module 30 . In this step, the server 25 may parse the friendly name portion 50 of the query string and compare the friendly name portion against a predetermined set of names, as described above. If the friendly name is in the predetermined set of names, the system proceeds to step 210 . Otherwise, the server 25 processes the HTTP URL as a conventional HTTP URL.
[0074] At step 210 , the server 25 diverts the query string by sending the query string to the diverting module 30 . At step 220 , the diverting module 30 receives the query string and at step 230 , the diverting module 30 parses the query string. Particularly, the diverting module 30 parses the query string to resolve a friendly name portion 50 at step 240 , a path and query portion 55 at step 250 , and a parameters portion 65 at step 270 .
[0075] At step 240 , the diverting module 30 parses the query string into a friendly name portion 50 , as the string “consultants” and an anchor point is set according to a predetermined anchor point list associated with the friendly name. For example, the anchor point associated with the friendly name “consultants” may be object B in the directory service 10 , as shown in FIG. 1 .
[0076] At step 250 , the diverting module 30 parses the query string into a path sub-portion as the string “//”. This sets the search scope to the entire sub-tree of the anchor point. In the directory service 10 of FIG. 1 , with an anchor point of object B. the search scope includes objects B, E, F, and H. The diverting module 30 parses the query string into a query sub-portion as the string “sn=Smith”. This sets the query sub-portion to search for an attribute of “sn”, or surname, with an attribute value of “Smith”.
[0077] At step 270 , the diverting module 30 parses the query string into a parameters portion 65 , as a null string. Thus, no optional parameters are included in the query string and default values are to be used.
[0078] At step 280 , the diverting module 30 builds a reformatted query that is compatible with the directory service 10 . Particularly, the reformatted query searches the search scope determined in steps 240 and 250 and with the parameters determined in step 270 . For example, the diverting module 30 builds a reformatted query that accesses the directory service 10 and searches user objects of objects B, E, F, and H for each object having an attribute of “sn” with an attribute value of “Smith”.
[0079] At step 290 , the diverting module 30 forwards the reformatted query to the directory service 10 and at step 300 , the directory service 10 replies to the reformatted query. The reply may be, for example, an XML formatted response or an LDAP response. At step 310 , the diverting module will reformat the response from directory service 10 to a format that is expected by the access devices 15 , for example HTML or XML. At step 320 , the access device 15 receives the information from the directory service 10 by way of server 25 and perhaps the diverting module 30 .
[0080] Thus, in the present invention, a web page may be constructed with HTTP URL links tailored to access information in the directory service 10 , and a user of the web page may access such information without being concerned with the actual construction of the links or understanding of APIs to access the directory service 10 . Therefore, the present invention provides an HTTP URL formatted query string employed to gain access to a directory service 10 .
[0081] It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the invention has been described with reference to preferred embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitations. Further, although the invention has been described herein with reference to particular elements, steps, and/or embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the spirit and scope of the appended claims. Those skilled in the art, having the benefit of the teachings of the present disclosure, may effect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention in its aspects. | Information is retrieved from a directory service via a Hyper Text Transport Protocol (HTTP) Universal Resource Locator (URL) query string which is parsed by a diverting module. The diverting module parses the HTTP URL query string into a plurality of portions. The diverting module constructs a directory service compatible query from the plurality of portions and requests information from the directory service with the directory service compatible query. | 8 |
CROSS REFERENCE TO PROVISIONAL APPLICATION
[0001] This application claims the benefit of the filing date of provisional application Ser. No. 60/599,409 filed Aug. 6, 2004.
BACKGROUND OF THE INVENTION
[0002] The invention relates to flushing assemblies for toilets such as flapper-style toilets and the like, and more particularly, to a flushing assembly which allows the user to select the volume of flush desired and thereby save water when a full flush is not needed.
[0003] So-called water saving toilets are known in the art, and are intended to conserve water by reducing the water used in a flush. Unfortunately, these toilets and associated flushing systems tend to use far more water than intended, and nevertheless provide a single volume flush. The need exists for an improved method of conserving water during operation of a toilet.
[0004] It is therefore the primary object of the present invention to provide an apparatus which allows improved conservation of water.
[0005] It is a further object of the present invention to provide such an apparatus which is simple in manufacture, simple to install, and simple and reliable in use.
[0006] Other objects and advantages of the present invention will appear below.
SUMMARY OF THE INVENTION
[0007] In accordance with the present invention, the foregoing objects and advantages have been readily attained.
[0008] According to the invention, a flushing assembly is provided which comprises a main body adapted for mounting to a toilet tank; and a flush handle assembly comprising a shaft rotatably mounted within the main body and operable in a full flush rotation position and a limited flush rotation position.
[0009] In accordance with the present invention, the two different operative positions of the flush handle assembly allow a user to selectively perform a full flush when needed, and a limited volume flush when sufficient, so that to conserve water.
[0010] The structure of the flush handle assembly is configured such that, in the limited flush rotation position, the flush handle assembly can be operated only to cause a partial flush of the toilet and, thereby, only allow a portion of the normal volume of a full flush to pass into the bowl.
[0011] Additional details of the present invention will be more clear upon a consideration of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A detailed description of preferred embodiments of the present invention follows, with reference to the attached drawings, wherein:
[0013] FIG. 1 is a top view of the main body of a flushing assembly in accordance with the present invention;
[0014] FIG. 2 is a side view of a portion of a main body and a shaft of the flush handle assembly in accordance with an embodiment of the present invention;
[0015] FIG. 3 is an end view of a main body component of a flushing assembly in accordance with the present invention;
[0016] FIG. 4 schematically illustrates operation of an apparatus In accordance with the present invention;
[0017] FIG. 4 a further schematically illustrates a portion of the main body and a portion of a shaft of the flush handle assembly in the two different operating positions in accordance with the present invention;
[0018] FIG. 5 illustrates the main body portion of an alternative embodiment of the flushing assembly of the present invention; and
[0019] FIG. 6 schematically illustrates a further alternative embodiment In accordance with the present invention.
DETAILED DESCRIPTION
[0020] The invention relates to a flushing assembly for use in toilets which flush through pivot of a portion of a handle assembly wherein the amount of pivot controls the volume of the flush. One non-limiting example of such a toilet is a flapper-style toilet, although other styles of toilet, for example some pressure type toilets, can also advantageously operate with the apparatus of the present invention. Flapper-style toilets, are well known, and have a water tank wherein a supply of water is stored for use in flushing. Inside the tank, there is a flapper valve which can be lifted to allow the water within the tank to flush the bowl of the toilet in well known fashion. In order to perform a flush, the flapper is typically connected through a chain or other connector to a lift arm, which itself is operatively connected to a handle external of the tank. Thus, pushing of the handle lifts the lift arm and opens the flapper to perform a flush.
[0021] In accordance with the present invention, a flusher assembly is provided which advantageously has two different flush positions, one wherein a normal full flush rotation can be performed, and another where only a limited flush rotation can be performed, wherein the limited rotation is sufficient to partially lift the flapper and allow some water to escape the tank into the bowl, but wherein the flapper is not fully lifted to perform a complete flush as with normal operation. This advantageously allows a user to perform a limited flush rotation when such a flush will be sufficient, and to configure the flushing assembly into the proper position for performing a full flush rotation when needed.
[0022] FIGS. 1-3 schematically illustrate elements of the flushing assembly in accordance with the present invention. In this regard, FIG. 1 is a top partially schematic view of the main body portion of a flushing assembly. FIG. 2 shows a shaft 12 of a flush handle assembly in accordance with the present invention and a portion of a main body 10 into which the shaft is rotatably mounted.
[0023] As will be evident from a discussion of details to follow, FIG. 1 is a top view of one embodiment In accordance with the present invention, while FIG. 2 shows certain structures in an inverted position to illustrate that various positioning of components are all when within the broad scope of the present invention. Referring further to FIG. 1 , main body 10 advantageously defines an inner passage 14 into which shaft 12 is rotatably positioned, and main body 10 is typically mounted through a tank wall 18 and secured in tank wall 18 using a nut 20 in well known fashion.
[0024] As shown in FIG. 2 , shaft 12 typically has a handle 16 which, in well known fashion, can be used to impart rotation of shaft 12 relative to main body 10 in well known fashion so as to cause a flush as desired.
[0025] Returning to FIG. 1 , main body 10 advantageously has a slot 22 which, in this embodiment, is positioned at an end 24 which faces toward the inside of the tank. This end 24 will be referred to herein as a tank-inside facing end.
[0026] Also as shown in FIG. 1 , in one preferred embodiment, a return stop 26 can advantageously be positioned extending further into the tank from end 24 , and advantageously having a return surface 28 aligned with slot 22 . As will be further discussed below, stop 26 advantageously helps to insure proper return of the flushing assembly to a rest position within slot 22 following a full flush.
[0027] In accordance with the invention, shaft 12 advantageously has a rest position relative to main body 10 , and can advantageously be biased toward this rest position, but can be moved axially, along a longitudinal axis of shaft 12 , relative to main body 10 , into a different rotating position. According to a preferred embodiment of the present invention, the rest position is a position wherein a surface, preferably a pin 30 ( FIG. 2 ) is positioned within slot 22 so that rotation of shaft 12 relative to main body 10 is limited by the extent to which pin 30 can rotate within slot 22 . The amount of rotation allowed, which is dictated by the position of stop surface 32 , should be selected to be sufficient to allow a lifting of the flapper of only a relatively small degree, for example, about one-half to one and one-half inches more or less, depending upon chain slack and other flapper or flushing mechanism variables. The amount of rotation should be sufficient to allow limited water flow from the tank to the bowl of the toilet, preferably suitable for clearing a bowl containing only liquid and paper waste, without causing a full flush.
[0028] When shaft 12 is moved axially relative to main body to the full flush rotation position, which is as is illustrated in FIG. 2 , pin 30 is not radially within slot 22 , and shaft 12 can therefore rotate normally relative to main body to allow a complete rotation and, thereby, a complete lifting of the lift arm structure and full lifting of the connected flapper as is well know.
[0029] A spring 34 , schematically illustrated in FIG. 2 , can advantageously be provided within inner passage 14 and engage between shaft 12 and main body 10 so as to bias shaft 12 toward the limited flush rotation position. In this regard, spring 34 can be seated between a spring stop surface 36 defined within main body 10 , and a shoulder 38 of shaft 12 . Of course, other structures can be defined within main body 10 or on shaft 12 to similarly engage with spring 34 . For example, instead of should 38 , shaft 12 could be provided having an additional pin or other structure against which spring 34 can apply its force.
[0030] The rear illustration of FIG. 3 further shows additional detail of main body 10 . Referring to FIGS. 1 and 3 collectively, main body 10 typically has a head 40 which typically lies outside the tank wall 18 when installed therein. Head 40 can have a rearwardly projecting inner portion 42 , in this embodiment a square inner portion 42 , which is configured to fit the opening within tank wall 18 and thereby prevent rotation of main body 10 relative to tank wall 18 when mounted therein.
[0031] A sleeve or substantially cylindrical portion extends further toward the inside of the tank from head 40 and square inner portion 42 , and this sleeve is referred to as element 44 . Sleeve 44 in the embodiment shown has threads which engage with nut 20 to allow for mounting. Sleeve 44 also advantageously defines inner passage 14 , and end 24 having slots 22 and return stop 26 , all as shown in FIGS. 1 and 3 . Main body 10 can be formed of any suitable material, either as a plastic injection molded or otherwise formed part, or can be made through any other well know manufacturing process.
[0032] Referring to FIGS. 4 and 4 a, operation of the apparatus in accordance with the present invention is further illustrated.
[0033] FIG. 4 schematically shows handle 16 and a lift arm 46 connected through a chain 48 to a flapper 50 . In accordance with the present invention, two different operating positions are defined by the shaft and flushing assembly of FIGS. 1-3 which are positioned between handle 16 and lift arm 45 . In the limited flush rotation position, which is preferably the rest position of the apparatus of the present invention, pin 30 is positioned within slot 22 as schematically illustrated in FIG. 4 a as the left position of pin 30 in the drawing. As shown, slot 22 and, particularly, stop surface 32 , engages pin 30 upon rotation of shaft 12 and resulting pivot of pin 30 , and prevents shaft 12 and pin 30 from rotating beyond the point of contact of pin 30 with stop surface 32 . This amount of rotation is selected to provide only a limited lift of lift arm 46 and, resultingly, only a limited lift of flapper 50 , as schematically illustrated in FIG. 4 by the relatively smaller arrows at handle 16 , lift arm 46 and flapper 50 . When a full flush is desired, the assembly is configured to the full flush rotation position, which is accomplished with the preferred embodiment by axially positioning shaft 12 toward the inside of the tank so as to axially slide pin 30 out of slot 22 the right-side position of pin 30 as shown in FIG. 4 a. In this position, stop surface 32 of slot 22 is not aligned to prevent rotation of pin 30 . Thus, a full or otherwise normally allowed range of rotation of shaft 12 and pivot of pin 30 can be accomplished in this position. This results in a full rotation of handle 16 , a full lift of lift arm 46 and a full opening of flapper 50 as schematically illustrated in FIG. 4 by the relatively larger arrows.
[0034] After pin 30 has been pivoted along with rotation of shaft 12 to a flush position, the weight of lift arm 46 or any other structure biases the handle 16 and lift arm 46 back to a rest position. In a limited flush, this will result in pin 30 returning back toward the return surface 52 of slot 22 . When returning from a full flush, pin 30 is outside of slot 22 . If the return movement is sufficiently rapid, pin 30 could skip past slot 22 and remain outside of same for the next flush. Since this is undesirable, in accordance with the preferred embodiment, return stop 26 is positioned as schematically also illustrated in FIG. 4 a, and return stop 26 catches pin 30 when pin 30 is in alignment with slot 22 so that the bias of spring 34 can push shaft 12 to the rest position with pin 30 inside slot 22 as desired. In order to accomplish this, it is most preferred that return stop 26 have stop surface 28 aligned, preferably coplanar, with return surface 52 of slot 22 as shown.
[0035] In accordance with a further alternative embodiment of the present invention, and as shown in FIG. 1 , tank-inside facing end 24 of main body 10 can advantageously have a sloped portion 54 which is positioned to help guide pin 30 back into slot 22 during return rotation after a flush in the full flush rotation position. Thus, in this embodiment, end 24 has a surface or portion 54 which is sloped relative to a perpendicular plane with respect to the axis 56 of main body 10 . Advantageously, the slope of portion 54 is toward slot 22 as shown in FIG. 1 . Of course, different angles of the sloped portion 54 can be selected depending upon effectiveness of positioning pin 30 within slot 22 as desired. FIG. 5 shows a further alternative embodiment in accordance with the present invention wherein a spring insertion access 58 is provided to allow for positioning of spring 34 within inner passage 14 so that components of the shaft assembly can be inserted through inner passage 14 and spring 34 after positioning of the spring. Access 50 can therefore advantageously be opening through the side wall of sleeve 44 which is of sufficient size to position the spring there through, preferably with some compression of the spring so that the spring extends beyond the extent of access 58 after proper positioning within inner passage 14 .
[0036] Turning now to FIG. 6 , a further alternative embodiment of the present invention is shown. In this embodiment, main body 10 is of an alternative configuration wherein the threads are positioned in a different location for securing to the tank wall. Of course, this is an alternative to the structure shown in the other figures, and numerous other structures for mounting in the tank wall can be used, all well within the broad scope of the present invention. As shown in FIG. 6 , sleeve 44 a of main body 10 a has a series of slot portions 60 , 62 , 64 defined therein. A first slot portion 60 is a radial slot and is positioned to define a limited range of motion in the limited flush rotation position. Slot 62 is a second radial slot and has a radial length which is greater than slot 60 , and slot 62 corresponds to a full flush rotation position. Axial slot 64 advantageously connects slot 60 and 62 such that pin 30 can travel along slot 60 , 62 , 64 for operation as desired within slot 60 and 64 , and positioning between slots 60 and 64 through slot 62 . Preferably, axial slot 62 is positioned connecting a rest or return-position end of slot 60 , 64 , such that axial positioning of pin 30 relative to main body 10 a is accomplished when the assembly is in the rest position.
[0037] Slot 60 , 62 , 64 are advantageously sized to receive pin 30 with a small amount of clearance to provide for a smooth but reliable operation as desired.
[0038] As mention above, it should be appreciated that slot 22 can be positioned in any of a large number of different positions in the structure of main body 10 . In the embodiment of FIG. 1 , slot 22 is positioned in a substantially 12-o'clock position. In the embodiment of FIG. 2 , slot is positioned at the opposite position, or at approximately 6-o'clock. It should be appreciated that this structure can be defined at any other location around the periphery of main body 10 , and can also be positioned in other places besides end face 24 . End face 24 is desired, however, due to ease of assembly since slot 22 can easily accept pin 30 during assembly of the device.
[0039] From a consideration of the foregoing, it should be readily appreciated that a simple and effective method and structure have been provided to allow for different volumes of flushing as desired and selected by a user, which advantageously provides the desired function of allowing a user to select the volume of a flush of the toilet depending upon the needs of the particular circumstances. Specifically, the limited flush will generally be suitable when the toilet contains only liquid and/or paper waste. Further, when a full flush is necessary, the assembly is easily operated to provide for same.
[0040] In further accordance with the invention, it may also be desirable to provide indicia, for example, on the handle 16 , which conveys to a user that a full flush can be accomplished by axially displacing the handle assembly relative to the main body. This can be conveyed through text, for example, “push for full flush”, or with arrows and pictures or the like.
[0041] It should be appreciated that the present invention provides an apparatus which operates in an easy and reliable fashion. The apparatus of the present invention also eliminates complicated mechanisms which might otherwise be attempted in order to provide the function of the present invention, such that the present invention provides simple manufacture and can be used simply and dependably for an extended period of time.
[0042] It should also be appreciated that the above detailed description provides explanation of various preferred embodiments of the present invention. However, these embodiments are illustrated only, and are not to be construed as limiting upon the scope of the present invention, which instead is defined by the claims which follow. | A flusher assembly includes a main body adapted for mounting to a toilet tank; and a flush handle assembly having a shaft rotatably mounted within the main body and operable in a full flush rotation position and a limited flush rotation. The assembly is simple, reliable and efficiently manufactured, and allows selection of full or limited volume flushing of toilets and, thereby, conservation of water. | 4 |
This application claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/001,868 filed on Nov.5, 2007.
BACKGROUND
This invention relates generally to a method for preparing M n B 12 H 12 , wherein M is a metal.
Processes for production of Na 2 B 12 H 12 from sodium borohydride and diethylsulfide-borane complex according to the following equation
2NaBH 4 +10Et 2 SBH 3 →Na 2 B 12 H 12 +13H 2 +10Et 2 S
are known, but they are inefficient in that diethylsulfide-borane complex is unstable in water and must be prepared in anhydrous solvent. For example, H. C. Miller, N. E. Miller, and E. L. Muetterties J. Am. Chem. Soc. 1964, 83, 3885-3886 describes production of Na 2 B 12 H 12 from sodium borohydride and diethylsulfide-borane complex at 120° C.
The problem addressed by this invention is to provide a more efficient process for producing M n B 12 H 12 .
STATEMENT OF INVENTION
The present invention is directed to a method for producing M n B 12 H 12 , wherein M is a metal or ammonium cation and n is one or two. The method comprises combining a metal borohydride and XBH 3 ; wherein X is an amine containing at least one aryl group, aralkyl group or branched alkyl group; a phosphine having three aryl, aralkyl or branched alkyl groups; or tetrahydrofuran.
DETAILED DESCRIPTION
Unless otherwise specified, all percentages herein are stated as weight percentages (“wt %”) and temperatures are in ° C.
An “aralkyl” group is an alkyl group substituted by at least one aryl group, e.g., benzyl, phenylethyl, etc. An “alkyl” group is a saturated hydrocarbyl group having from one to thirty carbon atoms, and may be linear, branched or cyclic. In some embodiments, alkyl groups have from one to twenty-two carbon atoms. An “aryl” group is a substituent derived from an aromatic hydrocarbon compound. An aryl group has a total of from six to twenty ring atoms, and has one or more rings which are separate or fused, and may be substituted by alkyl or halo groups.
In embodiments of the invention in which X is an amine containing at least one aryl group, aralkyl group or branched alkyl group, the amine nitrogen is substituted with at least one of said groups, with the remaining substituents being additional groups of the same types, linear alkyl groups, especially C 1 -C 4 alkyl groups, hydrogen atoms or a combination thereof In some embodiments, the amine contains only one aryl or aralkyl group. When the branched alkyl group is a tertiary alkyl group, preferably the other substituents on nitrogen are hydrogen atoms, methyl groups or ethyl groups. When the substituents other than the tertiary alkyl group are hydrogen atoms, the amine is a tertiary-alkyl primary amine, preferably one having at least eight carbon atoms. Examples of such tertiary-alkyl primary amines are the PRIMENE™ amines available from Rohm and Haas Company; Philadelphia, Pa. For example, an isomeric mixture of C 16 to C 22 tertiary alkyl primary amines (PRIMENE JM-T); an isomeric mixture of C 8 to C 10 tertiary alkyl primary amines (PRIMENE BC-9); an isomeric mixture of C 10 to C 15 tertiary alkyl primary amines (PRIMENE 81-R); or mixtures thereof. In some embodiments in which the branched alkyl group is a primary or secondary alkyl group, the amine has three branched alkyl groups, e.g., tri-isobutylamine and tri-isopropylamine. Preferably, the branched alkyl group has at least four carbon atoms. In some embodiments, the amine has one branched alkyl group and two methyl or ethyl groups. In some embodiments, the amine is a diamine in which each amino group contains at least one aryl group, aralkyl group or branched alkyl group. An example of such an amine is PRIMENE MD amine, available from Rohm and Haas Company; Philadelphia, Pa. In some embodiments, the amine has at least one aryl group selected from phenyl, tolyl, 1-naphthyl and 2-naphthyl. When an aryl group is present on the amine, preferably the other groups are hydrogen, methyl or ethyl.
In embodiments in which X is a phosphine having three aryl, aralkyl or branched alkyl groups, preferably the three groups are the same. Examples of suitable aryl groups include phenyl and tolyl. Preferably, branched alkyl groups have at least four carbon atoms.
In some embodiments of the invention, the amount of amine-borane complex, XBH 3 used is at least 0.995 equivalents with respect to the amount of metal borohydride, MBH 4 . The amine-borane complex may be used as the solvent, in which case there will be a very large excess of the amine-borane complex. In some embodiments of the invention in which the amine-borane complex is not used as the solvent, the amount of the complex is from 0.995 to 10 equivalents, alternatively no more than 5 equivalents, alternatively no more than 2 equivalents, alternatively no more than 1.5 equivalents, alternatively no more than 1.1 equivalents. An equation describing the reaction which occurs in the method of this invention, for the case where M is monovalent (n=1), is as follows:
2MBH 4 +10XBH 3 →M 2 B 12 H 12 +13H 2 +10X
Preferably, the reaction temperature is from 70° C. to 220° C., alternatively from 100° C. to 195° C.
In some embodiments of the invention, glyme solvents are used, e.g. ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether.
In some embodiments of the invention, M is an alkali metal, alkaline earth metal, ammonium or substituted ammonium; alternatively M is sodium, potassium, tetramethyl ammonium, tetraethyl ammonium, calcium, lithium or magnesium; alternatively M is sodium. For univalent metals, n=2 and for divalent metals, n=1. | A method for producing M n B 12 H 12 , wherein M is a metal or ammonium cation and n is one or two, by combining a metal borohydride and XBH 3 ; wherein X is a substituted amine; a substituted phosphine; or tetrahydrofuran. | 2 |
BRIEF SUMMARY OF THE INVENTION
The invention relates to aqueous mixed micelle solutions containing a salt of a cholanic acid, a lipid and a non-steroidol anti-inflammatory.
DETAILED DESCRIPTION OF THE INVENTION
Local irritations and haemolytic effects are frequently observed with the parenteral administration of non-steroidal anti-inflammatories. The object of the present invention is to make available a more tolerable parenteral application form for non-steroidal anti-inflammatories.
It is known from German Offenlegungsschrift No. 2 730 570 to use mixed micelles from cholanic acids and lipids for the solubilization of difficultly soluble or non-water soluble pharmaceutically active substances in an aqueous medium. It has surprisingly been found that aqueous mixed micelle solutions of non-steroidal anti-inflammatories are substantially more tolerable in the case of parenteral administration than aqueous-organic or even purely aqueous solutions of such anti-inflammatories which have not been manufactured using mixed micelles.
The present invention is concerned with aqueous mixed micelle solutions containing a salt of a cholanic acid, a lipid and a non-steroidal anti-inflammatory.
In another aspect the invention is concerned with the use of mixed micelles from cholanic acid salts and lipids for the solubilization of non-steroidal anti-inflammatories in aqueous media.
As cholanic acid salts there come into consideration in the present mixed micelle solutions the salts of cholanic acids or cholanic acid derivatives which are mentioned in DE-OS 2 730 570, especially cholates, glycocholates and taurocholates, especially the alkali salts such as the sodium salts. Sodium glycocholate is especially preferred.
As lipids, there come into consideration especially phosphatidylcholines, for example, natural lecithins or synthetic lecithins having modified side-chains, for example, those which are described in European Patent Application A2-0154977. Natural lecithins such as egg lecithin or soya lecithin are preferred.
Non-steroidal anti-inflammatories (non-steroidal anti-inflammatory drugs, NSAID's) in the sense of this invention are compounds which are structurally different from steroids and which display an anti-inflammatory activity. Such compounds are frequently characterized by the presence of a carboxylic acid group and/or are derivatives of acetic acid or of propionic acid. Examples of such non-steroidal anti-inflammatories are carprofen, ibuprofen, benoxaprofen, naproxen, sulindac, zomepirac, fenclofenac, alclofenac, ibufenac, flunixin, indomethacin or salts thereof. A preferred non-steroidal anti-inflammatory in the scope of the present invention is carprofen (6-chloro-α-methyl-carbazole-2-acetic acid) and physiologically compatible salts thereof with bases, for example, alkali metal hydroxides, amines or basic amino acids such as arginine or lysine.
The molar ratio between lipid and the cholanic acid conveniently lies in the order of 0.1:1 to 2:1. Mixture ratios of 0.8:1 to 1.5:1 are preferred.
The amount of lipid plus cholanic acid in the injection solution can vary over wide limits and can amount to, for example, 50-300 mg/ml of injection solution.
The amount of the pharmacon in the solutions in accordance with the invention can also vary over wide limits and can amount to, for example, 0.1-100 mg/ml of solution. By means of the solutions in accordance with the invention relatively large amounts of active substance can be solubilized in a volume unit, which is especially advantageous in the treatment of large animals.
The mixed micelle solutions in accordance with the invention can be prepared by simply mixing the individual ingredients. In another embodiment the lipid, the cholanic acid and a base suitable for forming a salt therewith, for example, an alkali hydroxide, or directly the cholanic acid salt as well as the active substance can be dissolved in an organic solvent, thereupon the organic solvent can be removed by evaporation and thereafter water, optionally isotonizing additives and, if desired, additional ingredients can be added, whereby as a rule the isotonizing additives and in most cases also the optional additional ingredients are admixed with the water prior to the addition to the mentioned evaporation residue. As organic solvents, there come into consideration those in which the components to be solubilized are sufficiently soluble, such as, for example, lower alkanols, especially methanol or ethanol.
In a further embodiment, an aqueous mixed micelle solution can be prepared firstly from a lipid and a cholanic acid salt and then the active substance can be added.
The time after stirring which is required until the thus-obtained mixture becomes homogeneous depends on the type of cholanic acid, lipid, active substance and the concentrations thereof and as a rule can be shortened by warming for a brief period.
The mixed micelle solutions in accordance with the invention are conveniently adjusted to a pH value of about 5.5-7.5.
The mixed micelle solutions, in accordance with the invention, can contain additional adjuvants, for example, buffers, isotonizing additives, stabilizers and/or preserving agents, for example, benzyl alcohol. As isotonizing additives, there come into consideration especially: sodium chloride, mannitol or glucose. Tris buffer, phosphate buffer, citrate buffer, glycine buffer, citrate-phosphate mixed buffers and the like can be used as the buffer. The osmotic pressure of the injection solutions, in accordance with the invention, should in the ideal case correspond to that of the blood, that is, about 300 mOsm, but can vary in certain limits.
Furthermore, conveniently the preparation of the solutions, in accordance with the invention can be carried out under an atmosphere of inert gas and by adding to the solution an antioxidant such as, for example, sodium ascorbate, sodium hydrogen sulfite or sodium pyrosulfite.
A preferred mixed micelle solution, in accordance with the invention, contains sodium glycocholate, a natural lecithin and carprofen or a salt thereof, especially the arginine or lysine salt.
Such a solution is especially suitable for use in veterinary medicine, for example, for the treatment of acute and chronic laminitis; skeletal disorders such as navicular disease; myositis; pains in the case of colics, especially flatulence and spastic colic; pains in the case of disorders of the respiratory tract; acute mastitis; and traumatic pains and for the treatment of disorders in the puerperal phase such as mastis, lacking of or insufficient uterus involution (postpartum involution).
The following Examples further illustrate the invention.
EXAMPLE 1
(a) 8.85 g of glycocholic acid are suspended in 50 ml of N 2 -gassed water for injection and dissolved with the aid of 1.9 ml of freshly prepared NaOH 40%.
(b) 16.9 g of finely divided lecithin are added thereto and dissolved while stirring well.
(c) The mixed micelle solution obtained is warmed to about 50°-60° C.
(d) 3 g of L-arginine are dissolved at about 40° C. in 15 ml of N 2 -gassed water for injection.
(e) 5 g of carprofen substance are suspended in the mixed micelle solution (c) pre-warmed at about 50°-60° C. and dissolved with the portionwise addition of the L-arginine solution (d).
(f) The solution obtained is adjusted to pH 6.0±0.2 with 2N HCl and made up to the final volume of 100 ml with N2-gassed water for injection.
(g) The solution is filtered through a membrane filter of 0.45 μm, filled into ampules under aseptic conditions and a N 2 atmosphere and sterilized in an autoclave.
EXAMPLE 2
The procedure of Example 1 is repeated, but 1.5 g of benzyl alcohol are added after operation (e).
EXAMPLE 3
9.86 g of glycocholic acid (containing 5.6% of water) and 3.48 g of L-arginine are dissolved in 60 ml of ethanol-water (2:1) at about 40° C. Thereafter, 17.77 g of lecithine are added thereto and dissolved. The organic solvent is evaporated in a rotating evaporator under reduced pressure whereby a foam is formed. Four (4.0) g of indomethacin and 1.95 g of L-arginine are dissolved at room temperature in 55 ml of N 2 -gassed water. The solution obtained is added to the foam obtained above and the mass is dissolved with stirring. The mixed micelle solution obtained is adjusted to pH 7.1±0.1 with 2N HCl and made up to a final volume of 100 ml with N 2 -gassed water for injection. Thereafter, one proceeds according to Example 1 (g).
EXAMPLE 4
9.86 g of glycocholic acid (containing 5.6% of water) and 3.48 g of L-arginine are dissolved in 50 ml of N 2 -gassed water for injection. Thereafter, one proceeds according to Example 1 (b) and (c) adding, however, 17.77 g of lecithin. 2.5 g of ibuprofen and 2.11 g of L-arginine are dissolved in 20 ml of methanol, whereupon the methanol is removed in a rotatory evaporator. The so-obtained powder is added to the mixed micelle solution and dissolved with stirring. The solution is then adjusted to pH 7.1±0.1, made up to a final volume of 100 ml with N 2 -gassed water for injection and filled into ampules as in Example 1 (g).
EXAMPLE 5
9.86 g of glycocholic acid (containing 5.6% of water) and 3.48 g of L-arginine are dissolved in 50 ml of N 2 -gassed water for injection. Thereafter, 2.5 g of naproxen and 1.89 g of L-arginine are added to the solution obtained and dissolved with stirring. Then, 17.77 g of finely divided lecithin are added to the solution and dissolved with stirring at about 40°-50° C. Thereafter, the pH is adjusted as in Example 3, the solution made up to a volume of 100 ml, filtered in filled into ampules.
EXAMPLE 6
In order to test the local tolerance, preparations A (control), B (formulation in accordance with the invention), C and D (conventional formulations) were administered intravenously once daily to dogs during 14 days.
______________________________________A NaCl 0.9%B Carprofen 50.0 mg L-Arginine 30.0 mg Glycocholic acid (anhydrous) 88.5 mg NaOH 40% 19.0 μl Lecithin for mixed micelles 169.0 mg HCl (2N, pH 6.0) q.s Water for injection ad 1.0 mlC Carprofen 10.0 mg Polyethylene glycol 400 600.0 μl Water for injection ad 1.0 mlD Carprofen 25.0 mg Diethanolamine 19.0 mg EDTA disodium salt 0.1 mg Benzyl alcohol 10.0 μl Water for injection ad 1.0 ml______________________________________
The medicated animals received 20 mg/kg of active substance. The injections were carried out each time at the same site (V. cephalica antebrachii).
RESULTS
In the case of the animal treated with C, an inflammation at site of administration appeared after 3 injections and the vein became closed after 6 injections.
In the case of the animal treated with D, the site of administration became inflamed even after the first administration. A third administration was not possible because of an obliteration of the veins. In the case of the animal treated with B and in the case of the control animal (A) no changes at the site of administration became evident after 14 injections. Upon autopsy, thrombophlebitis at the site of injection was evident in the case of animals treated with C and D; the animal treated with B was negative. | Aqueous mixed micelle solutions comprising cholanic acid salts and lipids used for the solubilization of non-steroidal anti-inflammatories and for the preparation of locally tolerable pharmaceutical administration forms for such medicaments, are described. | 8 |
BACKGROUND OF THE INVENTION
Public transportation is in a rapidly changing state. The existing systems have shortcomings that have been readily apparent for some time. The trend in development is to the personalized service vehicle on a public scale in order to replace the private automobile with a more efficient and effective means of public transportation.
With this thought in mind, trains are outmoded in that to be profitable they have to be too big and would run less often and serve fewer people. Buses present a pollution problem, are uncomfortable, and, as with the train, every time one person gets on or off all the passengers must wait. The automobile is not acceptable because of pollution, size and occupancy rate. Therefore, a completely new system must be found, one with units smaller than a car, that gives individualized service, that is non-polluting, inexpensive to run, and frees the driver from being tied to his vehicle.
One problem that exists with all transportation systems presently envisioned relates to storage. The storage of all vehicles not in use takes up an enormous amount of real estate. Railyards, parking lots, and bus depots all exist for the sole purpose of storing empty containers side-by-side or one after the other. If, on the other hand, vehicles were designed so that one end remains open and the units could fit into one another, storage would be cut down many times over.
SUMMARY OF THE INVENTION
With the above background in mind, it is a primary objective of the present invention to provide a personal rapid transit system with individual vehicles which are adapted to nest within one another for storage purposes. The system is to be designed for three dimensional travel to maximize personal service distribution.
It is envisioned that each individual unit would be a small vehicle made out of a strong material and desirably of single piece construction. For example, transportation tested plastic with reinforcement by metal rods is one expedient. The resultant unit would be light, and therefore the future guideways would also be lighter, for they would be built in proportion to the units using them. With weight considerations in mind, it is also of note that one of the heaviest parts of any rolling stock is the axle. Therefore, to cut down weight of the vehicle, elimination of this part would be advantageous. Consequently, the present design utilizes a monorail overhead system which eliminates the heaviest and bulkiest components of present transportation systems provides a container that is light, colorful, and vandal-proof and fits easily into one another of the same design. The unit can be stored in such a manner that in the space required by a present day car with a capacity of six people, 20 of the present units can be stored with a carrying capacity of 50 people.
Each vehicle or capsule is designed to maximize utilization of available seating space without having excess space. With this in mind, taking into account both technical and social considerations, the ultimate configuration would appear to be a unit with a two-seat capacity with the possibility of seating a child between the two. This would give the capsule a capacity of 2.5 persons, which is believed to be satisfactory under present conditions. Naturally, this can be varied depending upon changing conditions. It is also envisioned that occasionally a larger capacity will be required in which case the capsules can be designed so that two of them could interconnect for the duration of the journey. This would result in a temporary capacity of five per unit. The system is designed so that capacity is minimized to avoid problems present in conventional systems. A consistently larger capacity makes a more expensive system and a heavier system with empty seats that would constantly have to be transported unnecessarily. Today's automobiles have to carry the back seat even though the space is rarely used. The present design is structured to avoid that problem.
The present system is designed to be basically automatic with some control given to the passenger but always doublechecked by the overall controls. With present technology, there is no reason why the entire system cannot be computerized with passenger pushbuttons available to permit deviations in travel with the acceptance of the computerized control system.
It should also be noted that in the present system, when a unit reaches its destination, it is diverted to an off-line station so as not to interfere with any of the other vehicles using the system. Once in the system, each unit travels at a preselected speed from its point of origin to destination without slowing down or in any way interfering with any of the other units in operation. The system fulfills the needs of urban environment in that it is a four dimensional one that will serve the highrise resident as well as the basement living resident at any hour of the day.
The present system has substantially no station requirements, which further cuts costs. The system is designed with a no-wait capacity, there is no need for heavy construction and expense of hard to patrol stations. In essence, there will be a station wherever the people are, mainly at sidewalk level. Each sidewalk is already a platform above a collection of pipes and machinery. Once a mechanized system is presented to transport people, it makes no sense to have them climb up or down to where the machine travels. The system is designed so that it comes to the people and picks them up where they are, at sidewalk level, at roof level, or even within a building since the unit is small enough to pass right through window spaces.
Taxi stops can be provided which would be designed with a capacity to fill the requirements of a neighborhood and several cars would be assigned to each stop on a permanent basis. This means that when a person comes to a stop, he would see several units standing there. Once the passenger gets into the first capsule, he presses the start button and if the controls permit the unit would accelerate and slip into the main system. Appropriate buttons could be provided within the overall control to permit the passenger to direct the destination of the capsule.
In regard to empty units, each stop would be designed with certain unit capacity so that when one capsule enters the station that already contains the full complement of vehicles or capsules, the automatic controls would direct the first unit in line to leave the station and travel until it reaches a station that does not have a sufficient number of empty units whereupon it would exit and wait for a passenger at that point.
The basic configuration of the system would be of a loop to maximize travel in one direction only and eliminate the dead end situation. More complex designs could provide interconnection of several loops. Another advantage of the present system is in regard to shipment of freight. The capsules could be loaded with goods, sealed and directed under automatic controls to their exact destination thereby minimizing danger of pilferage. The system for freight shipment in this manner would be quick, efficient and economical.
In summary, the method and apparatus for a personalized rapid transit system is present. The system includes an interrconnected network of rails and support means to locate the rails in a predetermined three-dimensional pattern. A plurality of vehicles are provided with each vehicle adapted to carry at least one person therein and have a configuration which facilitates the removable nesting of vehicles when not in use. Finally, conductor and drive means are provided on each vehicle and connected to the network of rails so that the vehicle is suspended from the rail network and is guided and supported thereby during travel and storage.
With the above objectives, among others, in mind, reference is had to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1a is a schematic top plan view of the system of the invention;
FIG. 1b is a schematic front elevation view thereof;
FIG. 2 is a fragmentary perspective view of a portion of the system including a vehicle mounted thereon;
FIG. 3 is a fragmentary side elevation view thereof showing a plurality of vehicles in stacked stored condition;
FIG. 4 is a top plan view of a fragmentary portion of the system showing a plurality of vehicles in stacked stored condition; and
FIG. 5 is a front elevation view thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1a and 1b show system 20 in schematic form. A main route or loop 21 is shown for main travel and a side loop or secondary rail system 22 is shown in connection at two separate points with loop 21. The loops are constructed of a supported monorail system as shown in detail in FIG. 2. Naturally, two rail systems or other known rail systems can be utilized in place of the depicted monorail system and is a matter of choice.
Side loop 22 shows the versatility of the system. Not only does it deviate from the main path of loop 21 but it is inclined to demonstrate the three dimensional feature of the system and it passes through a building 23 by entering one window 24 and exiting through an opposing window 25. As shown, the building forms a station area where a plurality of vehicles 26 are stacked for use. A passenger in capsule 26 on line 21, by executing the proper control operation, can cause vehicle 26 to deviate onto path 22 and enter building 23 through window 24. He can then press the appropriate button to stop the vehicle and exit therefrom at which time the vehicle can be stacked as shown. When someone in the building thereafter decides to use a vehicle or capsule 26 he enters the front vehicle of the stacked group and shuts the door and operates the appropriate control so that the vehicle passes through window 25 and from side loop 22 into the main loop 21 and on to its desired location.
FIG. 2 shows the specific details of system 20. Rail 21 is depicted as a typical monorail overhead structure which is adapted to be inclined at any desired angle and directed in any horizontal direction. Appropriate supports such as upright member 27 and U-shaped grasping prong 28 are dimensioned and utilized so as to support the monorail in a fixed position. Naturally the interengagement between supports 27 and 28 and rail 21 can be accomplished in a conventional fashion such as welding or bolting the elements together.
Vehicle or capsule 26 is somewhat hemispherical in configuration with the forward portion 29 being more spherical than the rear portion 30. Rear portion 30 tapers gradually toward the rear end of capsule 26 so as to provide a smaller outer dimension on the rear half 30 of vehicle 26 than the forward half 29 of the vehicle. Extending from the top of vehicle 26 is the drive and connector assembly 31 which includes appropriate drive mechanisms and also has a pair of vertically spaced engaging wheels which are dimensioned so as to track on rail 21. The shafts which are connected with wheels 32 are conventionally rotatably mounted within the drive housing 31 so that when wheels 32 are tracked on monorail 21, the drive housing 31 and capsule 26 are both suspended on monorail 21 and supported thereby.
Each capsule or vehicle 26 is designed for specific structural purposes. These details are depicted specifically in FIGS. 3-5. The enlarged hemispherical forward portion 29 is partially constructed of a pair of opposing pivotal front doors 33 and 34 respectively. The doors are shiftable so that their adjacent edges meet when the doors are closed along a central seam 35 at which point appropriate latch mechanisms can be utilized to keep the capsule still. Adjacent to seam 35 which is formed when doors 33 and 34 are in the closed position are a pair of lights 36 mounted on the doors to facilitate operation of the vehicle at night. Each of the doors is hinged at the top and bottom to the remainder of the capsule by sliding bars 37 which are connected to the doors and are slidably mounted in the remainder of the capsule. Therefore when the doors are opened, they can be shifted rearwardly into overlapping position with respect to rear portion 30 of capsule 26 for a predetermined amount of area as depicted in FIG. 4. Sliding mechanisms 37 are of a conventional type which will permit the rotation of the doors as shown between the position indicated in FIGS. 4 and 5 and the closed position as indicated in FIG. 2.
The interior of vehicle 26 is basically in the form of a hollow chamber 38 for holding the passengers. It will be noted that all the elements of vehicle 26 are concave in configuration to maximize the size of chamber 38. As shown, and appropriate seat or bench 39 is placed within chamber 38 and is mounted to the inner walls of the capsule. As discussed above, this seating area should be sufficient to carry at least two passengers and probably have a capacity of 2.5. For nesting purposes, the seat should be located in rear portion 30 adjacent to the tapered rear side of the vehicle 26.
The structure is designed so that certain expedients are present for storing or nesting of the capsule to minimize the space required. As described above, the doors 33 and 34 are shiftable back along the outer surface of rear portion 30 in a concentric type of arrangement to provide a large open front for the vehicle. Then, as shown in FIG. 3, the lower portion 40 of seats 39 are rotatable between the substantial horizontal position and a somewhat vertical position in engagement with the back inner wall of the capsule. This is accomplished by means of pivot point 41 and serves to enlarge the chamber portion 38 within rear portion 30 during storage so that a greater portion of another vehicle can be received within the first vehicle. The storage position of seat 39 is depicted in FIG. 3 in solid lines and the operational position is depicted in dotted lines.
Therefore, when the doors have been opened as indicated and the seats have been retracted, the vehicles can be nested within one another as depicted in FIGS. 3-5. The only limitation on the degree of nesting resides in the positioning and size of the drive and connector housings 31. As shown, these housings are brought into abutment during storage. It can be readily seen how storage space is minimized by the stacking feature since a plurality of vehicles 26 can be stored within the same space occupied by a single vehicle in the operable closed position as shown in FIG. 2. For use, all that need be done is the seat shifted to the operable position, the user climb into chamber 38, takes his position in the seat, close the doors and push an appropriate button to advance the most forward of the stacked and stored vehicles.
Another feature which should be particularly pointed out is the off-set mounting of housing 31 with respect to capsule 26. The integral mounting structure 42, as shown in FIG. 5, is oriented away from the central forward portion of capsule 26 so as to minimize the danger of passenger contact with the overhead power and drive structure associated with housing 31.
Appropriate windows 43 are provided in the vehicle, both in the door and fixed portions of the capsule so as to give the maximum amount of visibility to the rider about a 360° circumference. The windows do not interfere with the operation of the vehicle nor the storage capabilities of the vehicle.
Thus, the above objectives of the invention, among others, are effectively attained. | A personalized rapid transit system incorporating an interconnected network of rails which are supported in a predetermined three dimensional pattern. A plurality of vehicles which are each adapted to carry at least one person and have a configuration which facilitates the removable nesting of vehicles when not in use are provided. Connection and drive apparatus is on each vehicle and is connected to the network of rails so that the vehicle is suspended from the rail network and is guided and supported thereby during travel and storage. | 4 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention pertains to the field of window balances. More particularly, the invention pertains to a wiper for the curl springs of these balances.
[0003] 2. Description of Related Art
[0004] Constant force curl springs have been used in window balance systems where they have the advantage of applying a constant lifting force to counterbalance the constant weight of a window sash. The constant force of these springs is derived from the curling tendency of an uncurled length of a spring steel strip that has been formed to curl up. When the strips are uncurled and extended, each increment of the extended strip is biased to recurl itself and thus exerts a constant force against spring extension.
[0005] However, until fairly recently, curl springs were not popular in window counterbalance systems, because each of their known arrangements suffered from at least one competitive drawback. For example, sash mounted arrangements of curl springs did not allow the sash to tilt; jamb mounted arrangements took up window space that manufacturers were unwilling to commit to balance systems; and tilt sash arrangements were inefficient and sometimes short-lived or inadequate in performance. The result was that only a few of the many different proposed arrangements of curl spring balance systems were being marketed, and these had only a small market share.
[0006] However, new discoveries in the realm of curl spring and shoe arrangement were patented in U.S. Pat. Nos. 5,353,548 and 5,463,793. The arrangements claimed in these patents accommodate a tilt sash and employ curl springs in a much more efficient manner. Curled up convolutions of the springs are carried by or contained within sash shoes, also referred to as curl spring mounts, that run in sash channels alongside a sash moving in sash runs. A connection between the shoes and the sash allows the sash to tilt, and the springs apply a constant counterbalance lifting force to the shoes, which transmit this lift to the sash. Free end regions of uncurled lengths of the springs are mounted within the shoe channels so that the springs curl up into the shoes as the shoes move upward in the shoe channels and uncurl from the shoes into the shoe channels as the shoes move downward in the shoe channels. Alternative designs involve the use of two shoes, one fixed to the window jamb channel at a desired location and a traveling shoe which contains one end of the curl spring and is affixed to the stile of the window sash so that as the sash is moved the traveling shoe uncoils the curl spring from the fixed shoe. The traveling shoe is also referred to as a locking shoe.
[0007] One specific problem that arises when such window designs are used in new construction is that when the curl spring is extended as the sash is moved from its resting position along the window jambs, there is a great potential for dust and dirt to attach to the extended spring. Then when the sash is returned to its resting or closed position and the spring is re-coiled within the shoes, the dust and dirt will accumulate within the coiled spring, causing it to become clogged. This can either partially or completely inhibit the movement of the sash. This problem is particularly acute with new construction because the windows are usually installed early in the construction process, before insulation and drywall are installed. Since drywall installation requires repeated sanding, the fine particulate plaster dust freely drifts around the room attaching itself not only to horizontal surfaces, but vertical ones, as well, such as the exposed curl springs of open windows, leading to the problems discussed above.
SUMMARY OF THE INVENTION
[0008] The invention is a spring wiper for curl springs used in window sash systems. The curl spring is contained in a coiled position within a carrier, mount, cassette, shoe or holder. The curl spring uncoils from its coiled position within the holder as the sash is moved either up or down to open the window. In a first embodiment of the invention, the spring wiper is deployed on top of and interlocks with features of the curl spring holder. In this first embodiment, the curl spring holder, or shoe, is pinned to the bottom of each of the two sash stiles by a sash pin while the open end of the spring is secured in the shoe channel at the end of the uppermost limit of travel of the bottom rail of the sash.
[0009] In a second embodiment of the invention, a curl spring mount is permanently secured at the top of the shoe channel of the window frame jamb. In this second embodiment, the end of the curl spring is secured to a locking shoe which is pinned to a stile of the sash by a sash pin which allows it to travel up and down the shoe channel as the sash is raised and lowered. In this embodiment, the spring slides along the surface of the shoe channel as the sash is raised and lowered. The wiper blade is an integral part of the curl spring mount and wipes the side of the spring facing the window opening as the sash is returned to its closed window position and the curl spring returns to its coiled position inside the curl spring mount.
[0010] The spring wiper has a wiper blade that is deployed on the curl spring holder or mount so that it presses against the side of the uncoiled portion of the curl spring that is exposed to airborne particulate contamination. The wiper blade has an edge that is preferably transverse to the curl spring, spanning its width, and wipes/scrapes debris clinging to and/or accumulated on the curl spring when it is extended prior to its being re-coiled within the curl spring mount or holder. In this way, it is able to keep such debris from entering the coiled portion of the curl spring and interfering with the continued fluid operation of the sash.
[0011] Either the first or the second embodiment may include a curl spring mount or holder that can accommodate more than one curl spring, usually two and sometimes three. The additional spring(s) would travel in and out of the curl spring mount or holder through an opening on the opposite side from the opening for the first curl spring. A separate wiper blade wipes clean the additional spring(s) before their re-entry into the curl spring mount or holder.
BRIEF DESCRIPTION OF THE DRAWING
[0012] FIG. 1 is a partially schematic side view of a window with sash shoe showing the balance system cooperating with a tilted sash.
[0013] FIG. 2 is a side view of the curl spring holder of FIG. 1 .
[0014] FIG. 3 is a cross-sectional view of the curl spring holder of FIG. 2 .
[0015] FIG. 4 provides a perspective view of the spring wiper for curl spring holders of the first embodiment of the invention.
[0016] FIG. 5 provides a schematic side view of the first embodiment of the spring wiper in functional position on a curl spring holder.
[0017] FIG. 6 provides a perspective view of the second embodiment of the invention with the curl spring extended between a fixed curl spring mount and a locking shoe.
[0018] FIG. 7 provides a perspective view of the second embodiment of FIG. 6 with the curl spring re-coiled within the fixed curl spring mount.
[0019] FIG. 8 provides a perspective view of the second embodiment showing a variation of the design of the spring wiper with the curl spring extended.
[0020] FIG. 9 provides a perspective view of the variation of the second embodiment of FIG. 8 with the curl spring re-coiled within the fixed curl spring mount.
DETAILED DESCRIPTION OF THE INVENTION
[0021] U.S. Pat. Nos. 5,353,548 and 5,463,793 provide numerous details related to the construction, operation and advantages of the curl spring holder 50 of the first embodiment of this invention and are hereby incorporated by reference. FIG. 1 schematically shows a generally preferred arrangement for employing curl springs 10 and curl spring holders 50 with a counterbalancing sash 20 . Free end regions 11 of springs 10 are fixed in positions within shoe channels 15 , as schematically indicated by fastener 12 . Curled up convolutions 13 of springs 10 are contained within curl spring holder 50 , which move up and down in shoe channels 15 as sash 20 moves up and down in vertical sash runs within the frame of the window (not shown). Curl spring holders 50 are interconnected with sash 20 , preferably by means of pivot bars or pins, which allow sash 20 to tilt, as shown in FIG. 1 . Curl spring holders 50 preferably lock in shoe channels 15 when sash 20 tilts, but it is also possible to allow curl spring holders 50 to rise in channels 15 from the upward bias of springs 10 when tilting of sash 20 removes some of the sash weight from curl spring holders 50 .
[0022] The curl spring counterbalance arrangement schematically shown in FIG. 1 achieves the general advantages mentioned above. In this design, potential friction caused by sliding an uncurled length of a curl spring against a shoe channel surface as a sash moves is substantially eliminated. Spring 10 rests flat and motionless against shoe channel wall 15 as spring 10 recurls into coiled convolutions 13 when curl spring holders 50 and sash 20 are moved upward and uncurls from curl spring holders 50 into shoe channel 15 when curl spring holders 50 and sash 20 are moved downward.
[0023] Containment of curled up spring convolutions 13 in curl spring holders 50 accommodates the balance springs to the vertical travel desired for sash 20 . Free end region 11 of spring 10 can be secured in shoe channel 15 above the uppermost limit of travel of curl spring holders 50 with sash 20 . This level can be above the upper rail of sash 20 , because a tilt latch, which is commonly arranged at the upper rail of a tilt sash (not shown), can move up and down over the mounting of free end region 11 without interference.
[0024] As illustrated in FIGS. 2 through 3 , curl spring holder 50 can advantageously be formed of two identical parts or halves 51 so that any one of the parts 51 can join with any other part 51 to form a complete body for curl spring holder 50 . Each body part 51 is formed to provide half of a containment region 53 for receiving the curled up convolutions 13 of spring 10 . Each body part 51 also provides half of an opening 52 for a pin or pivot bar receiver 60 . Opposite lower sides 54 of body parts 51 are parallel and separated by a suitable distance for a smooth sliding fit in shoe channel 15 , and upper sides 55 of body parts 51 are separated by a smaller distance to allow a length of spring 10 to pass from containment region 53 in between one of the curl spring mount side walls 55 and a wall of shoe channel 15 . Assembling curl spring holder 50 from a pair of identical body parts 51 also gives curl spring holder 50 identical front and rear faces so that the curl spring holder 50 can be installed with either face confronting sash 20 . Conventional moldable materials, such as plastics, resins, nylon and the like may be used to make the various components of the curl spring holder.
[0025] A projection 57 and a recess 58 are formed at the top of each body part 51 so that the downward facing portion 59 of each projection 57 can be slid into recess 58 of a confronting body part as shown in FIG. 3 . When body parts 51 are then pressed together, the downward facing portions of projections 59 interlocking with slots 58 and thus hold body parts 51 in the assembled relation of FIGS. 2 and 5 . Before this is done, curled spring convolutions 13 are placed in containment region 53 so that spring 10 extends out of an opening 56 , and receiver 60 is positioned in opening 52 between the body parts. This makes the assembly of curl spring holder 50 simple and inexpensive because it is accomplished by positioning a spring 10 and a receiver 60 in one body part and then simply pressing another body part into a confronting position that is held securely by the interference fit between projections 59 and slots 58 .
[0026] Receiver 60 has a preferably cylindrical body 61 with a through opening 62 that receives a pin or pivot bar connected to sash 20 . Receiver 60 thus participates in a connection between curl spring holder 50 and sash 20 , and many variations of such a connection are possible. A platform or other support can extend from curl spring holder 50 to sash 20 , for example. Window jambs normally include a slot between the sash run and the shoe channel 15 allowing a connector such as pin 63 to extend between curl spring holder 50 and sash 20 .
[0027] Receiver 60 preferably includes a cam 65 formed as an annular sector extending part way around cylindrical body 61 . Cam 65 fits within a recess 45 in each of the body parts 51 , and inclined cam follower surfaces 46 connect recess 45 with a confronting face surface 47 of each body part 51 . When cam surface 65 is positioned in recess 45 , in the neutral or sash vertical position for receiver 60 , confronting surfaces 47 of body parts 51 are closed or engaged. When sash 20 tilts, receiver 60 is turned or pivoted within curl spring holder 50 , which makes cam 65 ride up one of the inclined surfaces 46 onto face surface 47 . This spreads body parts 51 apart by the thickness of cam 65 . It also allows cam 65 to pivot in either direction to accomplish the cammed separation of body parts 51 . This thickens or widens curl spring holder 50 by increasing the separation between its front and back surfaces so that curl spring mount 50 locks in shoe channel 15 when sash 20 tilts. The amount that the curl spring mount widens is determined by the thickness of cam 65 , which can be varied to meet different shoe locking requirements. The top of curl spring holder 50 , which is held together by projections 59 in recesses 58 , remains tightly assembled, and shoe body parts 51 flex to allow the cammed separation of their lower regions when the shoe locks. This provides not only a simple locking arrangement for a sash curl spring holder, but it also provides more locking force from the torque applied by sash tilting than is achieved with other locking mechanisms that operate by spreading apart portions of the mount. The spreading of curl spring holder 50 occurs in a direction parallel with sash 20 , which extends across the narrower of the generally rectangular dimensions of shoe channel 15 ; and this may account for the improved locking force provided by cam 65 disposed between face surfaces 47 .
[0028] Curl spring holder 50 can also be provided with adjustable friction, although there is less need for friction adjustment in curl spring balance systems because of the normally constant force of the curl springs. If the spring lift is a little excessive, though, or if the upper sash has a tendency to drop from an uppermost position, the frictional fit of curl spring holder 50 in shoe channel 15 can be increased. This is preferably done by means of an opening 44 formed eccentrically into an upper region of body parts 51 so that openings 44 in a pair of assembled body parts do not register with each other. Then, a screw 43 can be threaded into an opening 44 in one of the body parts 51 , and its leading end will engage a confronting surface of the mating body part. Further turning of the screw will urge the upper regions of body parts 51 apart, to thicken curl spring holder 50 enough to increase its frictional resistance to movement in channel 15 .
[0029] When exposed to excessive dust, such as during new construction, including extremely fine particulates resulting from, for example, the repeated sanding of drywall in proximity to the window, this dust accumulates on the uncoiled length of curl spring 10 when sash 20 is moved from its resting or closed position (which draws curl spring 10 out of curl spring holder 50 and extends it along shoe channel 15 ). In this position, an inward side 10 A of the spring 10 , the side facing the window opening, is particularly exposed to dust accumulation, while a wall facing side 10 B rests flat against shoe channel wall 15 and is largely protected from such accumulation. Thus, it is extremely important that the inward side 10 A be cleaned prior to or while moving the sash 20 upward, as upward movement otherwise results in the recoiling of spring 10 within curl spring holder 50 , trapping construction dust in the curled up spring convolutions 13 within the curl spring holder 50 . Although not shown in the drawings, at least one more curl spring may be employed. The other spring(s) would travel in and out of the other side of the curl spring holder 50
[0030] In order to alleviate this problem, the first embodiment of the invention consists of a mounting apparatus 70 having a spring wiper 71 for curl spring holders 50 that is deployed on top of and engages interlocking features of curl spring holder 50 . The wiper blade 71 extends from a mounting apparatus (base 72 ) that can be affixed in spaced relationship adjacent spring 10 . In this embodiment, base 72 is mounted onto curl spring holder 50 via interlocking mating elements (projections 57 having heads 67 ) on the top of the curl spring holder 50 . Projections 57 and heads 67 snap onto or securely slide into interface elements (recesses 80 ) of the base 72 . Spring wiper 71 is inclined in relation to, and presses against, the inward surface 10 A of the curl spring 10 adjacent the curl spring holder 50 . Its edge 71 A is somewhat arcuate and transverse to the curl spring 10 and spans the width of the curl spring. Thus, as the curl spring holder 50 moves with the sash (and curl spring 10 recoils in its interior containment region 53 ), the edge 71 A of cleaning member 71 acts as a scraper, scraping dust and other detritus off of and away from the inward surface 10 A of curl spring 10 before it is recoiled into interior containment region 53 .
[0031] A second embodiment of the present invention is illustrated in FIGS. 6-9 . One variation is shown in FIGS. 6 and 7 . It consists of a curl spring mount 150 that contains an internal containment region for accommodating at least one curled up spring, as illustrated in the curl spring holder 50 in FIG. 3 . Instead of the curl spring mount 150 riding up and down a shoe channel in the window jamb, as described above with respect to the first embodiment, a locking shoe 160 is secured to the vertical stile of a sash (not shown) and travels in the shoe channel as the sash is moved up and down. The locking shoe 160 performs a function similar to that of curl spring mount 50 described in the first embodiment during the tilting operation of the sash. The curl spring mount 150 is secured at a fixed position within the shoe channel of the window jamb. One end of the curl spring 110 is securely affixed in a spring lock channel 180 of locking shoe 160 by a plurality of locking tabs 190 . At least one outwardly projecting wiper blade 171 a is an integral part of the body of the curl spring mount 150 . The outwardly projecting wiper blade 171 a is positioned to be in forceful contact with the exposed inward surface 110 a of curl spring 110 . As the window is closed, the sash is returned to its closed position. The locking shoe 160 returns to meet the curl spring mount 150 and curl spring 110 returns to its coiled position within curl spring mount 150 . As the curl spring 110 retracts into the curl spring mount 150 , surface 110 a is wiped of dust and other detritus by outwardly projecting wiper blade 171 a . Variations of this embodiment provide that at least one more spring may be incorporated within the curl spring mount 150 . The additional spring(s), at most two, would travel in and out of the curl spring mount 150 through an opening on the opposite side of the curl spring mount 150 from the opening for curl spring 110 . A separate integral wiper blade, also designated 171 a , wipes clean the additional spring(s) before re-entry into the curl spring mount 150 .
[0032] FIGS. 8 and 9 show another variation of the second embodiment of the invention, the only difference being that the wiper blade 171 b is projects inwardly. Either an outwardly projecting wiper blade 171 a or an inwardly projecting wiper blade 171 b is suitable for use with this second embodiment. The choice is simply the result of design optimization for each particular application. The wiper blade is made of a material that provides it with a degree of flexibility to exert a sufficient force on the inward surface 110 a of the curl spring 110 to enable it to remove unwanted dust and detritus therefrom. Suitable materials are well known and may include various molded plastics or elastomeric materials.
[0033] It should be readily apparent that the separate wiper 70 described within the curl spring balance system of the first embodiment may be used with the curl spring mount and locking shoe system, 150 and 160 , respectively, described within the second embodiment. Similarly, the integral wiper described in the second embodiment may be utilized with the curl spring holder 50 of the first embodiment. The common element is the wiper blade that is used to wipe the inward surface of the curl spring upon retraction into its curled position within the curl spring mount or holder within which it is housed.
[0034] However, and notwithstanding the foregoing description of a preferred embodiment, it is clear that numerous variations can be made without exceeding the scope of the inventive concept. Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention. | A spring wiper for curl springs contained within curl spring mounts, holders or shoes operatively engaged with window sashes that are located in window shoe channels. The spring wiper is deployed on the curl spring holder or mount and contains a wiper blade that is transverse to the curl spring, spanning its width, in order to wipe or scrape debris clinging to and/or accumulated on the surface of the curl spring exposed to airborne particulate matter when the curl spring is extended prior to its being retracted into the curl spring mount or holder, thereby keeping such debris from entering the inside of the curl spring mount or holder and interfering with the continued fluid operation of the sash. | 4 |
[0001] This application claims priority in provisional patent application Ser. No. 61/066,764 filed on Feb. 22, 2008 and provisional patent application Ser. No. 61/004,352 filed on Nov. 27, 2007 both of which are incorporated by reference herein.
[0002] The invention of this application relates to targets and, more particularly, to a rolled archery target.
INCORPORATION BY REFERENCE
[0003] U.S. Pat. No. 3,164,384 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 3,900,778 discloses an archery target configured from a corrugated material and is incorporated by reference herein for showing same. U.S. Pat. No. 1,837,627 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 3,048,401 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 3,396,971 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 2,990,179 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 4,076,246 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 4,244,585 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 5,865,440 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 6,926,281 discloses an archery target and is incorporated by reference herein for showing the same. U.K. Patent GB 2 365 366 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 2,818,258 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 5,290,042 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 7,222,860 discloses an archery target and is incorporated by reference herein for showing the same. U.S. Pat. No. 4,126,501 discloses an archery target and is incorporated by reference herein for showing the same.
BACKGROUND OF THE INVENTION
[0004] Archery targets have been around for many years and have had many configurations over these years. These include disc shaped targets, cylindrical targets, rectangular targets and even cube-shaped targets. Further, these targets have been formed by a wide range of material from hay to high technology composites. However, these prior art targets have had several deficiencies including high manufacturing costs and/or low life expectancy.
[0005] In this respect, many prior art archery targets, such as those formed by hay, produce an effective target but, quickly breakdown wherein replacement is necessarily early in the life of the target. Over the years, there have been improvements to the traditional hay targets which utilize materials such as corrugated materials to increase the life expectancy of the target. While vast improvements have been made, these changes to the target configuration have adversely impacted the costs of the target product by necessitating complicated manufacturing techniques and/or expensive materials.
[0006] For example, prior art targets include targets formed by closed cell foam sheet materials that are compressed and maintained between opposing rigid members by compression straps. While this target configuration is structurally solid and has been well received in the marketplace, production of the compressed sheet target is labor intensive and requires large scale equipment for the sizing of the foam sheet and for the compression of the foam sheets. Accordingly, while these compression sheet targets work well as an archery target, they can be costly and manufacturing high volumes of the targets can be difficult.
SUMMARY OF THE INVENTION
[0007] The invention of this application relates to an archery target. More particularly, the archery target according to the present invention includes a base member having an upwardly open support surface shaped to receive a cylindrical target portion formed by a foam sheet material wrapped about a horizontal axis.
[0008] In accordance with another aspect of the present invention, an archery target configured to absorb an impact of an associated arrow is provided which includes a stand having a top side and a bottom side and the bottom side including a support structure for supporting the archery target on an associated surface. The top side including a target rest shaped to receive a portion of an outer perimeter of a cylindrical target portion in shaped engagement. The target portion having a front side and a back side which extend between the outer perimeter and define a target depth and including a central core extending between front and back sides of the target. The core defining a target axis coaxial with the outer perimeter and the target portion further including at least one general planar sheet having side edges defining a sheet width that is generally equal to the target depth and a sheet surface between the side edges. The at least one sheet being wrapped about the core and the target axis and the side edges at least partially forming the arrow receiving zone wherein a portion of the sheet surface forming the outer perimeter.
[0009] According to another aspect of the present invention, the target portion has an elongated central core wherein the core is formed by a pliable material having a square cross-sectional configuration with a length and a width wherein the width is between 0.25 and 2.5 inches and the length extends in an axial direction and defines a central target axis. The square cross-sectional configuration of the core forming four general flat sides and the target further includes a planar sheet of pliable material extending between an inner end and an outer end and the sheet having side edges and a sheet surface that extend between the inner and outer ends. The inner end of the sheet being affixed to one of the four generally flat sides of the core such that the inner end is fixed relative to the core. The planar sheet extending about the core in tightly wrapped convolutions wherein the outer end and a portion of the sheet surface form an outer perimeter of the archery target and the core is substantially formed into a cylindrical core. The side edges of the sheet forming a front and back surface of the target which include at least one shooting surface and the target including at least one strap extending about at least a portion of the outer perimeter to maintain the tightly wrapped convolutions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The foregoing, and more, will in part be obvious in conjunction with a written description of the invention illustrated in the accompanying drawings in which:
[0011] FIG. 1 is a front view of a target according to the invention of this application;
[0012] FIG. 1A is a perspective view of a square core of one embodiment of the target shown in FIG. 1 ;
[0013] FIG. 2 is a side view of the target shown in FIG. 1 ;
[0014] FIG. 3 is a front view of two targets wherein one target is stacked on top of another target;
[0015] FIG. 4 is a front view of another embodiment of the target according to the invention of this application;
[0016] FIG. 5 is a front-side perspective view of yet another embodiment of the present invention including a two section stand;
[0017] FIG. 6 is an enlarged front-side perspective view of the stand shown in FIG. 5 ;
[0018] FIG. 7 is a front view of two targets, as is shown if FIG. 5 , wherein one target is stacked on top of another target;
[0019] FIG. 8 is a front-side perspective view of a further embodiment of this application including a stand spacer;
[0020] FIG. 9 is an enlarged front-side perspective view of the spacer shown in FIG. 8 ;
[0021] FIG. 10 is an enlarged front-side perspective view of the base shown in FIG. 8 ; and,
[0022] FIG. 11 is a front view of two targets, as is shown if FIG. 8 , wherein one target is stacked on top of another target.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0023] Referring now greater detail to the drawings wherein the showings are for the purpose of illustrating preferred embodiments of the invention only, and not for the purpose of limiting the invention, shown in FIGS. 1-4 is an archery target 10 formed by a target portion 12 and a stand 14 .
[0024] In one embodiment, target portion 12 is a wrapped target formed by the wrapping at least one general planar sheet of material 18 about a central axis 20 . This sheet material is preferably a pliable material that can deform when impacted by an arrow such that the target portion stops the linear motion of the arrow without damaging the arrow. This pliable material can be a wide range of materials including a foam material including, but not limited to, a closed cell foam.
[0025] In one embodiment, sheet material is a single continuous sheet wrapped about a central core 22 such that it extends from core 22 to an outer perimeter surface 24 . However, as can be appreciated, the target portion does not need to include the central core. Further, multiple sheets could be used. If included, the central core portion of the target also can be formed by a foam material similar to the layers extending about the core or can be formed by any material known in the art having material properties that will not damage an arrow when struck by the arrow.
[0026] Further, the outer surface 23 of core 22 can be cylindrical or the core can have a polygonal configuration or other configuration. In one embodiment, the core is cylindrical wherein the diameter of the central core can vary without detracting from the invention of this application. This can include cores from as small as around a ¼″ to several inches depending on the desired physical characteristics of the archery target.
[0027] In another embodiment, and with special reference to FIG. 1A , central core 22 s can have a four sided cross-sectional configuration having corners 26 and flats 27 between the corners. It has been found that this configuration works exceptionally well to prevent what is referred to as coning which is the result of the core moving relative to one or more of the layers of sheet material 18 . In one embodiment, core 22 s is a square core having a cross-sectional configuration wherein flats 27 are between 0.25 inches and 4.0 inches wide. As can be appreciated, the length of this core is dictated by the size of the target. In another embodiment, the flats 27 are between 0.25 inches and 2.0 inches wide. In yet another embodiment, the flats 27 are between 0.25 inches and 1.0 inch wide. In a further embodiment, the flats are between 0.40 inches and 0.60 inches wide and in yet another embodiment, the flats are approximately 0.50 inches.
[0028] When sheet material 18 is wrapped about core 22 , which will be discussed in greater detail below, an adhesive 28 can be used to secure end portion 29 of sheet material 18 to the core. This can also help prevent “coning.” With respect to core 22 S, adhesive 28 can be applied to a single flat 27 which is also the same single flap that end portion 29 engages as is shown in FIGS. 1 and 1A . Then, as the sheet material is tightly wrapped about core 22 s, the core is compressed such that it generally forms a cylindrical core structure even though it has a square configuration before wrapping.
[0029] The central core also can be formed by a different colored material to form a central target portion or can be formed by a similarly colored material to essentially hide the core from the remaining portion of the target portion. Again, while the central core is shown to be cylindrical even after wrapping, the invention of this application should not be limited to a cylindrical central core.
[0030] In yet another embodiment, the central core can be a removable core or can at least include a portion that is removable.
[0031] As is stated above, the target portion is formed by a sheet material wrapped about central axis 20 . The wrapping of this sheet material can be varied to produce different properties in the target portion. In this respect, the density of the target portion can be increased by wrapping the target portion with a higher tension such that the number of layers increases. It has been found that it is best to wrap the target portion under tension to increase the density of the wrapped layers. However, the amount of tension does not have to be great and can be varied based on a wide range of factors including the intended arrows, the environment for use and/or the shot distance.
[0032] The wrapped archery target can be maintained by a wide variety of structural elements. In one embodiment, straps 30 , 32 can be used to maintain the wrapped target portion. However, while two straps are shown, more or less straps could be used without attracting from the invention of this application. Further, the strap can have a wide range of cross-sectional configurations.
[0033] In other embodiments, other structural arrangements can be used by themselves or in combination with other structural elements to maintain the rolled condition of sheet material 18 . One of these includes an outer layer 34 that can be utilized to maintain the wrapped configuration of the target portion or merely utilized to create a printable surface for target indicia or insignia 35 that can be printed on cover 34 or even directly on a surface of sheets 18 . This outer layer can partially or completely surround the target portion. In one embodiment, this outer layer is an outer plastic layer that completely surrounds the target portion and is separate from a stand 14 which is best shown if FIG. 4 and which is discussed in greater detail below in accordance with yet other embodiments of the invention of this application. Further, straps 30 , 32 can be used in combination with outer layer 34 such that the straps maintain the wrapped condition of the sheets 18 while layer 34 is merely for visual purposes. As can be appreciated, layer 34 can be used to quickly customize target 10 based on customer requests.
[0034] In yet another embodiment, an adhesive can be used to maintain the wrapped condition or configuration of target portion 12 . This embodiment can include the application of an adhesive to at least one side of sheet material 18 during the wrapping of the target portion such that each layer adheres to an adjacent layer to maintain the wrapped configuration. Or, in another embodiment, only select layers can include adhesive such as the first and the last layer wherein adhesive is used between sheet material 18 and core 22 and adhesive is also used on the last one or more convolutions of the sheet material.
[0035] Target 10 can further include a handle 40 that can be secured to any portion of target 10 including secured to the top of target portion 12 as is shown. In one embodiment, handle 40 is secured by straps 30 and 32 .
[0036] After wrapping, sheet material 18 forms outer surfaces 42 , 44 and 46 of target portion 12 . However, as can be appreciated, these outer surfaces are formed by outer layer 34 when an outer layer is utilized even though they may be structurally based on the shape of sheet layers 18 . Again, any one or any combination of, these surfaces can have any one of a number of insignia in an arrow receiving zone that can be in surface 42 or 46 . These insignia can be any insignia known in the industry including, but not limited to, traditional target circles, deer configurations, multiple spaced targets incorporated thereon. Some of these insignia are shown in the prior art U.S. Pat. No. 7,222,860 which is incorporated by reference into the disclosure of this application. In yet another embodiment, outer layer 34 can be a removable outer layer such that it can be replaced when one or more of the insignia become overly damaged.
[0037] In yet another embodiment, target 10 can include stand 14 shaped to receive target portion 12 . Further, straps 30 and 32 also can be attached to stand 14 to secure target portion 12 relative to stand 14 in addition to securing the position of sheet 18 . Further, outer layer 34 can extend about target portion 12 to maintain the desired density of layers 18 wherein straps 30 and 32 can be used merely to secure the target portion relative to the base portion or layer 34 could also extend about the stand. While not shown, other combinations of securing devices and maintaining devices could be used without detracting from the invention of this application.
[0038] Stand 14 supports the target on a ground surface G which could be any type of underlying surface. Further, stand 14 can be sized to create the proper target height based on end use requirements. Stand 14 further includes target rest 60 which in one embodiment is an upwardly opened or facing curvilinear surface shaped to receive outer cylindrical surface 44 of target portion 12 . As a result, gravity alone can maintain the target portion relative to the base portion without the need of fasteners or other securing devices. However, rest 60 could be any one of a wide range of configurations such as having a V-shaped configuration or having a U-shaped configuration or even can be formed by more than two planar surfaces even though these configurations are not shown herein.
[0039] In yet another embodiment of the invention of this application, rest 60 can be formed by upwardly extending members 61 and 62 shaped to engage target portion 12 to maintain the position of target portion 12 relative to stand 50 . As discussed above, the members can include the curved surface or can form the curved surface. Further, as will be discussed more below, surface 60 does not need to be configured to be the exact same shape as outer surface 44 of target portion 12 wherein the entire surface does not need to engage the target portion.
[0040] Stand 14 also can have an axial length extending along axis 20 that is similar to the axial length of target portion 12 . However, the matching of the lengths of stand 14 and target 12 is not required.
[0041] Stand 14 further includes a base 69 to support target 10 on the ground surface as is discussed above. Base 69 is configured such that the target is stable and can withstand the impact of an arrow without falling over. This support structure or base can include a number of configurations that create a stable and steady target and these configurations can include the use of compressible and non-compressible materials. In one embodiment, not shown, base 69 is a flat base. In another embodiment, base 69 includes legs 70 and 72 having bottom surfaces 74 and 76 , respectively for engaging ground surface G. While these legs are shown to extend along the entire axial length of stand, this is not necessary for the target according to the present invention. However, this configuration could be utilized to reduce manufacturing costs such as allowing stand 14 to be extruded.
[0042] Stand 14 can be made from any known manufacturing technique in the art including, but not limited to, extruding, blow molding and injection molding. Stand 14 can further include one or more pockets, recesses, or compartments such as a compartment 80 configured to house any type of component and/or articles that could be used by an archer. As can be appreciated, this could include, but is not limited to, arrows, gloves and marking utensils.
[0043] As is discussed above, straps 30 and 32 can also extend about at least a portion of stand 14 . In one embodiment, stand 14 includes openings 90 and 92 thereby allowing straps 30 and 32 to extend through a portion of stand 14 . While not shown, the straps could extend about the bottom of the stand without detracting from the invention of this application. Further, outer layer 34 could also extend about stand 14 thereby securing target portion 12 to the stand.
[0044] With reference to FIG. 3 , shown are targets 10 a and 10 b wherein the targets can be configured to be stackable. In this respect stand 14 can include a downwardly facing or bottom stacking recess 94 that is shaped to matingly receive the top portion of another target 10 . This configuration can be used to stack one target on another target for reducing shipping and/or storage costs and/or can be used by the end user to produce multiple targets. While not shown, a securing device could be utilized to secure target 10 a to target 10 b. As with rest 60 , recess 94 can be a curvilinear surface shaped to receive outer cylindrical surface 44 of an adjacent target portion 12 . However, as with rest 60 , recess 94 could be any one of a wide range of configurations such as having a V-shaped configuration or having a U-shaped configuration or even can be formed by more than two planar surfaces.
[0045] In even yet another embodiment, stand 14 can further include a handle pocket or recess 82 configured to allow one target to sit on top of another target such that the handle of the other target is received by the pocket and the handle is not damaged during shipment. Further, this configuration can add to the stability of the top target, namely target 10 a as is shown in FIG. 3 .
[0046] In yet another embodiment, stand 14 can be used in connection with a cylindrical target that is not formed by layers 48 . In this respect, other techniques known in the art could be used in connection with stand 14 wherein the improved stacking and transporting ability of the target can be utilized with other target configurations.
[0047] With special reference to FIGS. 5-7 , shown are yet other embodiments of the invention of this application. In this respect, shown is a target 100 that can include any or all of the features described above with respect to target 10 but, which also includes a universal stand structure 114 that can be used on a wide range of target sizes. More particularly, stand 114 includes a first stand section 120 and a second stand section 122 . While not required, sections 120 and 122 can be configured the same such that a single section can be used for both sides. As can be appreciated, manufacturing costs can be reduced by having a single common component for both sections 120 and 122 .
[0048] Section 120 includes a locking tab 130 and section 122 includes a locking tab 132 . In addition, section 120 includes a lock receiver 140 and section 122 includes a lock receiver 142 . Lock receiver 140 is shaped to lockingly receive locking tab 132 and lock receiver 142 is shaped to lockingly receive locking tab 130 such that section 120 can be locked to section 122 . Again, sections 120 and 122 can be identical sections or at least substantially similar such that a single section design can be used for both. Once sections 120 and 122 are locked together, they form stand 114 which will support target 12 as is discussed in greater detail above.
[0049] Section 120 can further include openings 150 and 152 which are shaped to receive straps 30 and 32 . Similarly, section 122 includes openings 160 and 162 shaped to receive straps 30 and 32 . As a result, straps 30 and 32 can extend through both sections and at least partially hold these sections together. Further sections 120 and 122 can include any other feature as discussed above with respect to stand 14 including together forming a stacking recess 170 . As a result, target 110 a can be stacked on target 110 b as is shown in FIG. 7 .
[0050] In yet another embodiment, target 210 can include one or more spacers such as spacers 220 and 222 to enlarge the width of the stand and forms stand 214 shown in FIGS. 8-11 . More particularly, stand 214 includes sections 120 and 122 with spacers 220 and 222 joining sections 120 and 122 such that stand 214 is wider than stand 114 even though the same stand sections are used for both. This configuration allow for additional manufacturing savings in that one stand section can also be used for multiple size targets. While only one size of spacer is shown, different sized spacers can be used to create a range of target sizes with a single base section configuration.
[0051] With special reference to FIG. 9 , spacers 220 and 222 include a spacer locking tab 232 and a spacer lock receiver 234 such that lock receiver 234 is shaped to receive one of section tabs 130 and 132 of sections 120 and 122 , respectively, and spacer tab 232 is shaped to engage one of section receivers 140 and 142 of sections 120 and 122 , respectively. This configuration creates a gap or space 240 between sections 120 and 122 which increases the overall width of the stand. Again, sections 120 , 122 and spacers 220 and 222 can include any other feature as discussed above with respect to stand 14 and/or 114 including together forming a stacking recess 242 . As a result, target 210 a can be stacked on target 210 b as is shown in FIG. 11 .
[0052] Spacers 220 and 222 can further include locking keys 250 and 252 configured to engage key pockets 260 and 262 in the sections on either side of the respective spacer tabs. With special reference to FIG. 10 , spacers 220 and 220 are shown wherein spacer 220 extends between tab 130 of section 120 and receiver 142 of section 122 ; spacer 222 extends between tab 132 of section 122 and receiver 140 of section 120 . Section 120 includes pockets 260 and 262 which receive keys 250 and 252 , respectively, of spacer 220 . Similarly, section 122 includes pockets 260 and 262 which receive keys 250 and 252 , respectively, of spacer 222 . These spacers create gap 240 between inner edges 270 and 272 of sections 120 and 122 , respectively.
[0053] It has been found that a target according to the present invention can be made as follows. An adhesive is applied to the central core and the planar sheet material is adhered to a side of this central core. As is discussed in greater detail above, the central core can have a square cross-sectional configuration and the adhesive can be applied to one of the four sides of this elongated square core. Then, once the sheet is adhered to the one side of the square core, the sheet is tightly wrapped about the core to form a substantial portion of the target portion of the archery target.
[0054] As the sheet layer is tightly wrapped about the core, it deforms the core and the core forms a generally cylindrical shape. By using a square core and the adhesive connection, a significant property change takes place in this rolled target. In this respect, a target that is merely rolled about an axis has structural deficiencies which are realized once the target is used in the field. In this respect, the arrow impact and/or the removal of the arrow can cause what is referenced above as “coning.” This is where the core, or another section of the target, move relative to other convolutions in the wrapped target portion. This creates a cone-like configuration where each convolution remains generally coaxial to each other but, one or more of the convolutions move axially relative to one another.
[0055] The sheet layer is wrapped until the desired target portion size is reached. As can be appreciated, this can vary based on the users target preferences. Once the desired size is achieved, the wrapped layers need to be secured in place to prevent both unwrapping and/or decompression of the compressible material used. In this respect, it has been found that closed cell foam works well to make the target of the invention of this application while it must be noted that other material could be used without detracting from the invention. This material is compressed during the wrapping process wherein this compression can be used to improve the overall properties of the target. The layers can be secured by straps that extend about the outer perimeter of these wrapped layers to hold them in place. Further, adhesives can be used to help secure the layers in place layer by layer or at specific layers such as the inner surface of the outer layer.
[0056] The target of this application can further include a stand to support the target and to prevent unwanted motion such as rolling motion from the cylindrical configuration of the target portion. This stand can be a two section stand such as a two common section stand that is configured to form half of the stand structure. The strap reference above can be either wrapped about the target portion only or also wrapped into the stand structure. Accordingly, once the target portion is wrapped, the strap or straps are positioned about the outer perimeter of the target portion and through the stand. Then, the straps are tightened to the desired tension to maintain the compression of the target portion and to securely attach the stand to the target portion. At this time, the target can be finalized which can include the addition of insignia or other markings. It can also include the addition of an outer layer if it is intended to extend about the target portion and/or stand. If the outer layer is only intended to be wrapped about the target portion, it can be positioned before the straps are put in place.
[0057] While considerable emphasis has been placed on the preferred embodiments of the invention illustrated and described herein, it will be appreciated that other embodiments and/or equivalents thereof can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. Accordingly, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. | An archery target configured to absorb an impact of an associated arrow. The target having a stand having a top side and a bottom side and the bottom side including a support structure for supporting the archery target on an associated surface. The top side including a target rest shaped to receive a portion of an outer perimeter of a cylindrical target portion in shaped engagement. The target portion having a front side and a back side which extend between the outer perimeter and define a target depth and including a central core extending between front and back sides of the target. The core defining a target axis coaxial with the outer perimeter and the target portion further including at least one general planar sheet having side edges defining a sheet width that is generally equal to the target depth and a sheet surface between the side edges. The at least one sheet being wrapped about the core and the target axis and the side edges at least partially forming the arrow receiving zone wherein a portion of the sheet surface forms the outer perimeter. | 5 |
The invention relates to a percussion jig of the kind having a carrier for material to be separated and which is reciprocable in a settling tub.
BACKGROUND OF THE INVENTION
In a known percussion jig of the general class to which the invention relates the carrier for material to be separated is pivotally mounted at one end in the settling tub. The pivotal movement of the material carrier about the mounting point is achieved by means of a hydraulic or pneumatic drive cylinder which engages on the other end of the material carrier. A jig of this kind is disclosed in German Offenlegungschrift No. 31 15 247.
A significant disadvantage of this known percussion jig resides in the considerable wear to which the pivot mounting point of the material carrier is subjected during on It has a further drawback in that any maintenance and repair work necessary at the mounting point is awkward to carry out and requires the percussion jig to be shut down for long periods.
The objects of the invention, therefore, are to avoid these disadvantages and to provide a percussion jig in which very little wear is produced on the moving parts in operation and any necessary maintenance work can be carried out easily and without long periods of disuse.
SUMMARY OF THE INVENTION
The material carrier of a percussion jig according to the invention is freely suspended in the region of its centroidal axis on a piston rod forming part of the hydraulic drive cylinder. There thus is no need for a separate pivot mounting point for the material carrier in the settling tub. As a result the construction of the percussion jig not only is significantly simplified, but at the same time the wear which occurs of necessity at such a pivot mounting point during operation is avoided.
In operation the freely suspended material carrier of the percussion jig according to the invention moves to and fro in a straight line in the vertical direction and therefore the material carrier can be guided by simple structural means.
THE DRAWINGS
Advantageous embodiments of the invention are illustrated in the accompanying drawings, wherein:
FIG. 1 is a diagrammatic elevational view of a percussion jig having two settlement sections;
FIG. 2 is a section along the line II--II of FIG. 1;
FIG. 3 is a view similar to FIG. 1, but illustrating a variant;
FIG. 4 is a section along the line IV--IV of FIG. 2 and on an enlarged scale;
FIG. 5 is a view similar corresponding to FIG. 4 through a further embodiment;
FIG. 6 is a vertical partial view on an enlarged scale of a modified form of the apparatus for vertical guiding of the material carrier;
FIGS. 7-11 illustrate various stroke diagrams; and
FIG. 12 is a block wiring an diagram of an electronic control for a percussion jig.
DETAILED DESCRIPTION
The percussion jig illustrated in FIGS. 1 and 2 contains two settlement sections 1, 2 which are of identical construction and consequently only the construction of the settlement section 1 is explained in greater detail below.
A carrier 4 for material to be separated is movable in the vertical direction in the stationary settling tub 3 which is filled with water and forms the settlement section 1. The material carrier 4 contains side walls 5 and 6 as well as a separating screen 7 and is connected to the piston rod 9 of a double-acting hydraulic cylinder 10 by means of a central column 8 arranged in the region of its centroidal axis. The material carrier 4 and the parts supported thereon are reciprocated in a vertical direction (double headed arrow 11) by the hydraulic cylinder 10. Guide units 12, 13 which are explained in greater detail with reference to FIGS. 4 and 5 are provided to guide the material carrier within the settling tub 3.
A discharge gate 14 which can be actuated by a separate hydraulic cylinder 15 via a lever bar 16 is mounted on the material carrier 4. When the material carrier 4 is moved vertically the discharge gate 14 is moved with it so that the discharge aperture 17 between the material carrier 4 and the discharge gate 14 remains constant.
A material supply hopper through which the material to be separated is delivered to the settlement section 1 is designated by 18. A plurality of pipes 19 are provided in the settlement sections 1 and 2 for the supply of bottom water. An outlet shaft 20 in which an overflow pipe 21 is also arranged is connected to the settlement section 2.
In the percussion jig illustrated in FIGS. 1 and 2 three different products are extracted (arrows 22, 23, 24) through the settlement sections 1 and 2 and through the outlet shaft 20. It is possible, however, for more than two settlement sections to be arranged one behind the other.
In the variant illustrated in FIG. 3 the separating screen 7 is supported on an axis 25 so as to be pivotable on the material carrier 4. The inclination of the separating screen 7 relative to the material carrier 4 can be adjusted by means of a separate hydraulic cylinder 26. Like the discharge gate 14 and the hydraulic cylinder 15 which serves to move such discharge gate, the hydraulic cylinder 26 is mounted on the vertically movable material carrier 4 and is movable with the latter. Otherwise, the embodiment according to FIG. 3 corresponds to the arrangement according to FIGS. 1 and 2.
FIG. 4 shows an embodiment of the guide units 12, 13 (FIG. 2) which serves for vertical guiding of the material carrier 4 relative to the stationary settling tub 3.
A guide rail 27 is mounted in the region of each of the two guide units 12 and 13 on the periphery of the material carrier 4 and is in sliding contact with three slide parts 28, 29, 30 which are arranged in the settling tub 3 and can be adjusted from the exterior by means of setscrews 32, 33. A washing water supply 34 is connected to channels provided in the slide parts 28, 29, 30 and supplies washing water to the sliding surface between the guide rail 27 and the slide parts 28, 29, 30. In operation the material carrier 4 which is freely suspended in its centroidal axis moves in a vertical direction (i.e., perpendicular to the drawing plane of FIG. 4) and is satisfactorily guided in the region of the two guide units 12, 13 (FIG. 2) by the guide rail 27 and the slide parts 28, 29, 30.
In the embodiment according to FIG. 5 a guide rail 35 of triangular cross-section is provided in the region of the two guide units 12, 13 (FIG. 2) on the periphery of the material carrier 4 and is in sliding contact with two slide parts 36,37 which are arranged on the inner periphery of the settling tub 3 and are adjustable from the exterior by means of setscrews 38, 39. Here too a washing water supply 40 is connected to the channels provided in the slide parts 36, 37. The way in which this guiding arrangement operates during the movement of the material carrier 4 perpendicular to the drawing plane of FIG. 5 should be readily understood.
FIG. 6 shows a further embodiment of guiding means for the material carrier 4 in its vertical movement (double headed arrow 41) in the settling tub 3. The settling tub 3 is provided in the region of each of its two side walls (i.e., adjacent to the side walls 5 and 6 of the material carrier 4, see FIG. 2) with a guide lever system consisting of two control levers 42, 43 and an intermediate lever 44. The levers 42, 43 have one end pivoted on holders 45, 46 and their other ends pivoted on the intermediate lever 44 which, in turn, is pivoted at its center on the material carrier 4. As can be seen from FIG. 6, during the vertical movement of the material carrier 4 the guide lever system formed by the levers 42, 43 and 44 holds the central plane 47 of the material carrier 4 in the illustrated position, i.e. in the same vertical plane in which (in the region of the centroidal axis of the material carrier 4) the piston rod 9 of the hydraulic drive cylinder 10 engages.
With the aid of FIGS. 7 to 12 an embodiment of the percussion jig according to the invention is explained in which an electronically controlled hydraulic drive construction having an adjustable stroke diagram is provided.
Exhaustive experiments by the inventors with synthetic mixtures of coal and quartz sand and with natural rawfine coal showed that there is no single optimum diagram of the lifting and lowering movement for the successive separating processes in a percussion jig. On the contrary, the diagram must be adapted to the conditions in the machine which vary from delivery to discharge.
FIGS. 7 to 10 show four idealized theoretical basic forms of the stroke diagram in which the stroke height (mm) is plotted in the ordinate and the time (sec) in the abscissa.
The stroke diagram according to FIG. 7 includes a rapid downward movement with constant speed and a slow upward movement with equally constant speed. In FIG. 8 the conditions are reversed.
FIG. 9 shows a trapezoidal stroke diagram with a rapid constant downward speed, a certain holding period and a rapid constant upward speed.
FIG. 10 shows a stroke diagram with equal upward and downward speed.
In the exhaustive experiments referred to above it also proved significant that the loosening of the material to be separated which is necessary for the settlement process can be improved by superimposing a higher-frequency harmonic vibration on a basic movement path. This results in improved loosening of the material above all in the region closely surrounding the individual grains of the granular mixture to be separated.
FIG. 11 shows such a stroke diagram in which a higher-frequency harmonic vibration is superimposed on the trapezoidal basic diagram of FIG. 9 in the range of the holding period.
FIG. 12 shows an embodiment of the percussion jig according to the invention with which any selected stroke diagrams can be achieved.
The illustrated percussion jig 51 contains a settling tub 52 filled with water and a material carrier which is moved mechanically in the settling tub 52 and has a separating screen 53. The material carrier with the separating screen 53 is connected to the piston rod 54 of a double-acting hydraulic cylinder 55 which forms an electronically controlled hydraulic drive means for the material carrier.
Connected to the moving material carrier is a discharge gate 56 which is connected to the piston rod 57 of a double-acting hydraulic cylinder 58 which is moved upwards and downwards with the material carrier by the piston rod 54 of the hydraulic cylinder 55.
The percussion jig 51 also contains two floats 59 and 60 as well as samplers 61, 62, 63 in the region of the material supply, the material extractions from the illustrated first settling tank, and from the region of the junction with a following settling tank which is not illustrated.
The double-acting hydraulic cylinder 55 is controlled via a proportional valve 64 by a PID controller 65 which is connected to a setting means and a displacement pickup 66 connected to the piston of the hydraulic cylinder 55 in order to form a closed position control circuit. The setting means is formed by a curve creator 67 and a voltage-controlled oscillator 68 the outputs of which are connected to the theoretical value input of the PID controller 65.
Thus the path of the piston of the hydraulic cylinder 55 follows the theoretical value which is variable with time according to the chosen stroke diagram. The movement of the working piston can be put together synthetically as regards the upward stroke, the holding period, the downward stroke, and any sinusoidal superimposition (according to frequency and amplitude).
The theoretical values are fed into a computer 70 via a keyboard 69. There could be a choice, for example, of two different input modes. In a first mode (stroke regulation) the theoretical values for the number of strokes (strokes per minute), the upward and downward speed (mm/s), the holding period (s) and the heterodyne frequency are fed into the computer 70 via the keyboard 69. From such values the computer calculates the theoretical value for the stroke height and passes this value via a digital-analog converter 71 to a comparator 72.
This compares the theoretical value with the actual value of the stroke and ends the selected movement by means of switches 73, 74. The theoretical value for the stroke movement is frozen, i.e., held at the value at the moment of stopping, until all parallel-running settling tank drives (of several settling tanks) are synchronized and the holding period has expired. In this way absolute parallel running of a plurality of settling tanks is ensured in continuous operation.
The theoretical values for the upward and downward speed stored in the digital-analog converters 75, 76 are displayed in absolute terms in mm/s by LED displays.
After the theoretical values for the number of strokes and the holding period have been fed to the computer, the calculated stroke (mm) is displayed by the converter 71. The same applies to the stroke height of parallel-running settling tanks. The digital-analog converter 77 supplies the oscillator 68 which produces the higher-frequency heterodyne oscillation. The stroke height can be altered as a function of the height of the layer measured by the float 60 so that the stroke is optimized automatically by the height of the layer.
In a second possible mode (frequency regulation) the theoretical values for the stroke, the upward and downward speed, the heterodyne frequency and the holding period are predetermined. The number of strokes is calculated from the theoretical values.
As with the stroke regulation, in the case of frequency regulation too the automatic optimization of the stroke height as a function of the height of the layer is possible. The proportional factor can be set on a control element 78.
Finally the discharge regulation should be explained. It serves the purpose of supplying the materials separated by the settlement process to different outlets.
The control element is the discharge gate 56 which has already been mentioned above and is connected to the piston of the double-acting hydraulic cylinder 58. This cylinder 58 is controlled via a proportional valve 79 by a PID controller 80 which is connected to the float 59 which acts as the setting means and to a displacement pickup 81 connected to the piston of the hydraulic cylinder 58 in order to form a closed position control circuit. The float 59 is set so that it is heavier than the upper material layer and lighter than the lower material layer.
A minimum value storage unit 91 is connected to the float 59 and ensures that only the float signal measured in the jigged state of the settling tank is used for discharge regulation since the measurement values obtained during the jigging and settlement periods are not representative.
The position control circuit can be led through a superimposed cascade which contains an amplifier 82 and a digital-analog converter 83 and uses the ratio of the specific gravities of the two materials to be separated as the standard size.
The optimum degree of separation is achieved when this ratio is a maximum. However, this presupposes the taking, preparation, and evaluation of samples. Sample sample processing apparatus 85, 86,.87, sample analysis apparatus 88, and an analog-digital converter 89 serve for this.
In any case it is possible to move the cross-section by means of a theoretical value correction when this is necessary on the basis of manual samples. By means of a keyboard 90 a correction value is passed via the converter 83 to the regulator 80. | The invention relates to a percussion jig in which the carrier for material to be separated is freely suspended in the region of its centroidal axis on the piston rod of a hydraulic drive cylinder. This results in a particularly simple construction subject to little wear. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a utility patent application claiming the benefit of priority from commonly owned and U.S. Provisional Patent Application Ser. No. 61/763,293, entitled “Waveform Marker Placement Algorithm for Use in Neurophysiologic Monitoring,” and filed on Feb. 11, 2013, the entire contents of which is hereby expressly incorporated by reference into this disclosure as if set forth in its entirety herein.
FIELD
The present invention relates to a system and methods generally aimed at surgery. More particularly, the present invention is directed at a system and related methods for performing surgical procedures and assessments involving the use of neurophysiologic recordings.
BACKGROUND
Neurophysiologic monitoring has become an increasingly important adjunct to surgical procedures where neural tissue may be at risk. Spinal surgery, in particular, involves working close to delicate tissue in and surrounding the spine, which can be damaged in any number of ways. Various neurophysiological techniques have been attempted and developed to monitor delicate nerve tissue during surgery in attempts to reduce the risk inherent in spine surgery (and surgery in general). Because of the complex structure of the spine and nervous system, no single monitoring technique has been developed that may adequately assess the risk to nervous tissue in all situations and complex techniques are often utilized in conjunction with one or more other complex monitoring techniques.
One such technique is somatosensory evoked potential (SSEP) monitoring which may be quite effective at detecting changes in the health of the dorsal column tracts of the spinal cord. SSEP (and other types of neurophysiologic monitoring) involves complex analysis and specially-trained neurophysiologists are often called upon to perform the monitoring. Even though performed by specialists, interpreting complex waveforms in this fashion is nonetheless disadvantageously time consuming, adding to the duration of the operation and translating into increased health care costs. For example, most neurophysiology systems require that a neurophysiologist visually identify the morphology of the SSEP responses, manually mark waveform amplitudes and latencies, and track those amplitude and latency values over time. Even more costly is the fact that the neurophysiologist is required in addition to the actual surgeon performing the spinal operation. The present invention is directed at eliminating, or at least reducing the effects of, the above-described problems with the prior art.
SUMMARY OF THE INVENTION
The present invention includes a system and methods for avoiding harm to neural tissue during surgery. According to a broad aspect, the present invention includes instruments capable of stimulating either the peripheral nerves of a patient, the spinal cord of a patient, or both, additional instruments capable of recording the evoked somatosensory responses, and a processing system. The instrument is configured to deliver a stimulation signal preoperatively, perioperatively, and postoperatively. The processing unit is further programmed to and measure the response of nerves depolarized by said stimulation signals as received by the somatosensory cortex to indicate spinal cord health.
According to another broad aspect, the present invention includes a control unit, a patient module, and a plurality of surgical accessories adapted to couple to the patient module. The control unit includes a power supply and is programmed to receive user commands, activate stimulation in a plurality of predetermined modes, process signal data according to defined algorithms, display received parameters and processed data, and monitor system status. The patient module is in communication with the control unit. The patient module is within the sterile field. The patient module includes signal conditioning circuitry, stimulator drive circuitry, and signal conditioning circuitry required to perform said stimulation in said predetermined modes. The patient module includes a processor programmed to perform a plurality of predetermined functions including at least two of static pedicle integrity testing, dynamic pedicle integrity testing, nerve proximity detection, neuromuscular pathway assessment, manual motor evoked potential monitoring, automatic motor evoked potential monitoring, manual somatosensory evoked potential monitoring, automatic motor evoked potential monitoring, non-evoked monitoring, and surgical navigation.
According to another broad aspect, the present invention includes a neurophysiologic waveform marker placement algorithm that takes a discrete SSEP response, isolates the waveform from the noise, and automatically places latency markers on the isolated neurophysiologic signal.
BRIEF DESCRIPTION OF THE DRAWINGS
Many advantages of the present invention will be apparent to those skilled in the art with a reading of this specification in conjunction with the attached drawings, wherein like reference numerals are applied to like elements and wherein:
FIG. 1 is a block diagram of an example neurophysiology system capable of conducting multiple nerve and spinal cord monitoring functions including but not necessarily limited to SSEP Manual, SSEP Automatic, MEP Manual, MEP Automatic, neuromuscular pathway, bone integrity, nerve detection, and nerve pathology (evoked or free-run EMG) assessments;
FIG. 2 is a perspective view showing examples of several components of the neurophysiology system of FIG. 1 ;
FIG. 3 is an exemplary screen display illustrating one embodiment of an SSEP profile selection screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 4 is an exemplary screen display illustrating a second embodiment of a SSEP Manual Stimulus Mode setting with a Left Ulnar Nerve (LUN) Breakout screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 5 is an exemplary screen display illustrating one embodiment of an SSEP Manual Run screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 6 is an exemplary screen display illustrating a second embodiment of an SSEP Manual Run screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 7 is an exemplary screen display illustrating a third embodiment of an SSEP Manual Run screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 8 is an exemplary screen display illustrating a fourth embodiment of an SSEP Manual Run screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 9 is an exemplary screen display illustrating one embodiment of an SSEP Automatic Test Setting screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 10 is an exemplary screen display illustrating one embodiment of an SSEP Automatic Run screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 11 is an exemplary screen display illustrating a second embodiment of an SSEP Automatic Run screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 12 is an exemplary screen display illustrating a third embodiment of an SSEP Automatic Run screen forming part of the neurophysiology system of FIG. 1 ;
FIG. 13 is a flow chart detailing the steps of the waveform marker placement algorithm according to one embodiment.
FIG. 14 is a flow chart detailing the steps involved in the waveform processing portion of the algorithm of FIG. 13 ;
FIG. 15 depicts an example raw waveform to be processed according to the waveform marker placement algorithm of FIG. 13 ;
FIG. 16 depicts the resultant waveform after processing via a first step of the flow chart of FIG. 14 ;
FIG. 17 depicts the resultant waveform after further processing via a second step of the flow chart of FIG. 14 ;
FIG. 18 depicts the resultant waveform after further processing via a third step of the flow chart of FIG. 14 ;
FIG. 19 depicts the resultant waveform after further processing via a fourth step of the flow chart of FIG. 14 ;
FIG. 20 depicts the resultant waveform after further processing via a fifth step of the flow chart of FIG. 14 ;
FIG. 21 is a flow chart detailing the steps of the predictive waveform morphology search portion of the algorithm of FIG. 13 ;
FIG. 22 depicts an example of a first signal classification parameter of the flow chart of FIG. 21 ;
FIG. 23 depicts an example of a second signal classification parameter of the flow chart of FIG. 21 ;
FIG. 24 depicts an example of a third signal classification parameter of the flow chart of FIG. 21 ;
FIG. 25 depicts a signal identified as a potential physiologic signal following completion of the predictive waveform morphology search steps of the flow chart of FIG. 21 ;
FIG. 26 depicts a signal excluded as a potential physiologic signal following completion of the predictive waveform morphology search steps of the flow chart of FIG. 21 ;
FIG. 27 is a flow chart detailing the steps of the marker location search portion of the algorithm of FIG. 13 ;
FIG. 28 depicts the marker placement on a likely physiologic signal based on a reference search as detailed in the flow chart of FIG. 27 ;
FIG. 29 depicts the marker placement on a waveform in which a likely physiologic signal was not found based on a reference search as detailed in the flow chart of FIG. 27 ;
FIG. 30 shows narrowing of the original search windows via the comparative search placement function; and
FIG. 31 is a flow chart detailing the steps of the comparative marker placement function.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. The systems disclosed herein boast a variety of inventive features and components that warrant patent protection, both individually and in combination. It is also expressly noted that, although described herein largely in terms of use in spinal surgery, the neuromonitoring system and related methods described herein are suitable for use in any number of additional procedures, surgical or otherwise, wherein assessing the health of the spinal cord and/or various other nerve tissue may prove beneficial. It is further expressly noted that, although described herein largely in terms of SSEP testing, the waveform marker placement algorithms described herein are suitable for use with any number of additional physiologic responses types, including but not limited to brainstem auditory evoked potentials (BAEPs).
A neuromonitoring system 10 is described herein and is capable of performing a number of neurophysiological and/or guidance assessments at the direction of the surgeon (and/or other members of the surgical team). By way of example only, FIGS. 1-2 illustrate the basic components of the neurophysiology system 10 . The system comprises a control unit 12 (including a main display 34 preferably equipped with a graphical user interface (GUI) and a processing unit 36 that collectively contain the essential processing capabilities for controlling the system 10 ), a patient module 14 , a stimulation accessory (e.g. a stimulation probe 16 , stimulation clip 18 for connection to various surgical instruments, an inline stimulation hub 20 , and stimulation electrodes 22 ), and a plurality of recording electrodes 24 for detecting electrical potentials. The stimulation clip 18 may be used to connect any of a variety of surgical instruments to the system 10 , including, but not necessarily limited to a pedicle access needle 26 , k-wire 27 , tap 28 , dilator(s) 30 , tissue retractor 32 , etc. One or more secondary feedback devices (e.g. secondary display 46 ) may also be provided for additional expression of output to a user and/or receiving input from the user.
The functions performed by the neuromonitoring system 10 may include, but are not necessarily limited to, the Twitch Test, Free-run EMG, Basic Stimulated EMG, Dynamic Stimulated EMG, XLIF®, Nerve Retractor, MEP Manual, MEP Automatic, and SSEP Manual, SSEP Automatic, and Navigated Guidance modes, all of which will be described briefly below. The Twitch Test mode is designed to assess the neuromuscular pathway via the so-called “train-of-four test” to ensure the neuromuscular pathway is free from muscle relaxants prior to performing neurophysiology-based testing, such as bone integrity (e.g. pedicle) testing, nerve detection, and nerve retraction. This is described in greater detail within PCT Patent App. No. PCT/US2005/036089, entitled “System and Methods for Assessing the Neuromuscular Pathway Prior to Nerve Testing,” filed Oct. 7, 2005, the entire contents of which is hereby incorporated by reference as if set forth fully herein. The Basic Stimulated EMG Dynamic Stimulated EMG tests are designed to assess the integrity of bone (e.g. pedicle) during all aspects of pilot hole formation (e.g., via an awl), pilot hole preparation (e.g. via a tap), and screw introduction (during and after). These modes are described in greater detail in PCT Patent App. No. PCT/US02/35047 entitled “System and Methods for Performing Percutaneous Pedicle Integrity Assessments,” filed on Oct. 30, 2002, and PCT Patent App. No. PCT/US2004/025550, entitled “System and Methods for Performing Dynamic Pedicle Integrity Assessments,” filed on Aug. 5, 2004 the entire contents of which are both hereby incorporated by reference as if set forth fully herein. The XLIF mode is designed to detect the presence of nerves during the use of the various surgical access instruments of the neuromonitoring system 10 , including the pedicle access needle 26 , k-wire 42 , dilator 44 , and retractor assembly 70 . This mode is described in greater detail within PCT Patent App. No. PCT/US2002/22247, entitled “System and Methods for Determining Nerve Proximity, Direction, and Pathology During Surgery,” filed on Jul. 11, 2002, the entire contents of which is hereby incorporated by reference as if set forth fully herein. The Nerve Retractor mode is designed to assess the health or pathology of a nerve before, during, and after retraction of the nerve during a surgical procedure. This mode is described in greater detail within PCT Patent App. No. PCT/US2002/30617, entitled “System and Methods for Performing Surgical Procedures and Assessments,” filed on Sep. 25, 2002, the entire contents of which are hereby incorporated by reference as if set forth fully herein. The MEP Auto and MEP Manual modes are designed to test the motor pathway to detect potential damage to the spinal cord by stimulating the motor cortex in the brain and recording the resulting EMG response of various muscles in the upper and lower extremities. The SSEP function is designed to test the sensory pathway to detect potential damage to the spinal cord by stimulating peripheral nerves inferior to the target spinal level and recording the action potential from sensors superior to the spinal level. The MEP Auto, MEP manual, and SSEP modes are described in greater detail within PCT Patent App. No. PCT/US2006/003966, entitled “System and Methods for Performing Neurophysiologic Assessments During Spine Surgery,” filed on Feb. 2, 2006, the entire contents of which is hereby incorporated by reference as if set forth fully herein. The SSEP Auto and SSEP Manual modes are described in greater detail within PCT Patent App. No. PCT/US/2009/05650, entitled “Neurophysiologic Monitoring System and Related Methods,” filed on Oct. 15, 2008, the entire contents of which is hereby incorporated by reference as if set forth fully herein. The Navigated Guidance function is designed to facilitate the safe and reproducible use of surgical instruments and/or implants by providing the ability to determine the optimal or desired trajectory for surgical instruments and/or implants and monitor the trajectory of surgical instruments and/or implants during surgery. This mode is described in greater detail within PCT Patent App. No. PCT/US2007/11962, entitled “Surgical Trajectory Monitoring System and Related Methods,” filed on Jul. 30, 2007, and PCT Patent App. No. PCT/US2008/12121, the entire contents of which are each incorporated herein by reference as if set forth fully herein. These functions will be explained now in brief detail.
Before further addressing the various functional modes of the neurophysiologic system 10 , the hardware components and features of the system 10 will be describe in further detail. The control unit 12 of the neurophysiology system 10 includes a main display 34 and a processing unit 36 , which collectively contain the essential processing capabilities for controlling the neurophysiology system 10 . The main display 34 is preferably equipped with a graphical user interface (GUI) capable of graphically communicating information to the user and receiving instructions from the user. The processing unit 36 contains computer hardware and software that commands the stimulation source (e.g. patient module 14 ), receives digital and/or analog signals and other information from the patient module 14 , processes SSEP response signals, and displays the processed data to the user via the display 34 . The primary functions of the software within the control unit 12 include receiving user commands via the touch screen main display 34 , activating stimulation in the appropriate mode (Basic Stimulated EMG, Dynamic Stimulated EMG, XLIF, MEP automatic, MEP manual, SSEP manual, SSEP auto, and Twitch Test), processing signal data according to defined algorithms, displaying received parameters and processed data, and monitoring system status. According to one example embodiment, the main display 34 may comprise a 15 ″ LCD display equipped with suitable touch screen technology and the processing unit 36 may comprise a 2 GHz. The processing unit 36 further includes a powered USB port 38 for connection to the patient module 14 , a media drive (e.g. CD, CD-RW, DVD, DVD-RW, etc. . . . ), a network port, wireless network card, and a plurality of additional ports 42 (e.g. USB, IEEE 1394, infrared, etc. . . . ) for attaching additional accessories, such as for example only, navigated guidance sensors, auxiliary stimulation anodes, and external devices (e.g. printer, keyboard, mouse, etc. . . . ). Preferably, during use the control unit 12 sits near the surgical table but outside the surgical field, such as for example, on a table top or a mobile stand. It will be appreciated, however, that if properly draped and protected, the control unit 12 may be located within the surgical (sterile) field.
The patient module 14 contains a digital communications interface to communicate with the control unit 12 , as well as the electrical connections to all recording and stimulation electrodes, signal conditioning circuitry, stimulator drive and steering circuitry, and signal conditioning circuitry required to perform all of the functional modes of the neurophysiology system 10 , including but not necessarily limited to Basic Stimulated EMG, Dynamic Stimulated EMG, XLIF®, Twitch Test, MEP Manual and MEP Automatic, and SSEP Manual and SSEP Automatic. In one example, the patient module 14 includes thirty-two recording channels and eleven stimulation channels. A display (e.g. an LCD screen) may be provided on the face of the patient module 14 , and may be utilized for showing simple status readouts (for example, results of a power on test, the electrode harnesses attached, and impedance data, etc. . . . ) or more procedure related data (for example, a stimulation threshold result, current stimulation level, selected function, etc. . . . ). The patient module 14 may be positioned near the patient in the sterile field during surgery.
To connect the array of recording electrodes 24 and stimulation electrodes 22 utilized by the system 10 , the patient module 14 also includes a plurality of electrode harness ports. To simplify setup of the system 10 , all of the recording electrodes 24 and stimulation electrodes 22 that are required to perform one of the various functional modes (including a common electrode 23 providing a ground reference to pre-amplifiers in the patient module 14 , and an anode electrode 25 providing a return path for the stimulation current) may be bundled together and provided in single electrode harness 80 . Depending on the desired function or functions to be used during a particular procedure, different groupings of recoding electrodes 24 and stimulation electrodes 22 may be required. According to one embodiment (set forth by way of example only), the electrode harnesses 80 are designed such that the various electrodes may be positioned about the patient (and preferably labeled accordingly) as described in Table 1 for SSEP:
TABLE 1
SSEP
Electrode Type
Electrode Placement
Spinal Level
Ground
Shoulder
—
Stimulation
Left Post Tibial Nerve
—
Stimulation
Left Ulnar Nerve
—
Stimulation
Right Post Tibial Nerve
—
Stimulation
Right Ulnar Nerve
—
Recording
Left Popliteal Fossa
—
Recording
Left Erb's Point
—
Recording
Left Scalp Cp3
—
Recording
Right Popliteal Fossa
—
Recording
Right Erb's Point
—
Recording
Right Scalp Cp4
—
Recording
Center Scalp Fpz
—
Recording
Center Scalp Cz
—
Recording
Center Cervical Spine
—
Having described an example embodiment of the system 10 and the hardware components that comprise it, the neurophysiological functionality and methodology of the system 10 will now be described in further detail.
The neuromonitoring system 10 performs assessments of spinal cord health using one or more of SSEP Auto, and SSEP manual modes. In the SSEP modes, the neuromonitoring system 10 stimulates peripheral sensory nerves that exit the spinal cord below the level of surgery and then measures the electrical action potential from electrodes located on the nervous system superior to the surgical target site. Recording sites below the applicable target site are also preferably monitored as a positive control measure to ensure variances from normal or expected results are not due to problems with the stimulation signal deliver (e.g. misplaced stimulation electrode, inadequate stimulation signal parameters, etc.). To accomplish this, stimulation electrodes 22 may be placed on the skin over the desired peripheral nerve (such as by way of example only, the left and right Posterior Tibial nerve and/or the left and right Ulnar nerve) and recording electrodes 24 are positioned on the recording sites (such as, by way of example only, C2 vertebra, Cp3 scalp, Cp4 scalp, Erb's point, Popliteal Fossa) and stimulation signals are delivered from the patient module 14 .
Damage in the spinal cord may disrupt the transmission of the signal up along the spinothalamic pathway through the spinal cord resulting in a weakened, delayed, or absent signal at the recording sites superior to the surgery location (e.g. cortical and subcortical sites). To check for these occurrences, the system 10 monitors the amplitude and latency of the evoked signal response. According to one embodiment, the system 10 may perform SSEP in either of two modes: Automatic mode and Manual mode. In SSEP Auto mode, the system 10 compares the difference between the amplitude and latency of the signal response vs. the amplitude and latency of a baseline signal response. The difference is compared against predetermined “safe” and “unsafe” levels and the results are displayed on display 34 . According to one embodiment, the system may determine safe and unsafe levels based on each of the amplitude and latency values for each of the cortical and subcortical sites individually, for each stimulation channel. That is, if either of the subcortical and cortical amplitudes decrease by a predetermined level, or either of the subcortical and cortical latency values increase by a predetermined level, the system may issue a warning. By way of example, the alert may comprise a Red, Yellow, Green type warning associated with the applicable channel wherein Red indicates that at least one of the determined values falls within the unsafe level, the color green may indicate that all of the values fall within the safe level, and the color yellow may indicate that at least one of the values falls between the safe and unsafe levels. To generate more information, the system 10 may analyze the results in combination. With this information, in addition to the Red, Yellow, and Green alerts, the system 10 may indicate possible causes for the results achieved. In SSEP Manual mode, signal response waveforms and amplitude and latency values associated with those waveforms are displayed for the user. The user then makes the comparison between a baseline the signal response.
FIGS. 3-8 are exemplary screen displays of the “SSEP Manual” mode according to one embodiment of the neuromonitoring system 10 . FIG. 3 illustrates an intra-operative monitoring (TOM) setup screen from which various features and parameters of the SSEP Manual mode may be controlled and/or adjusted by the user as desired. Using this screen, the user has the opportunity to toggle between Manual mode and Automatic mode, select a stimulation rate, and change one or more stimulation settings (e.g. stimulation current, pulse width, and polarity) for each stimulation target site (e.g. left ulnar nerve, right ulnar nerve, left tibial nerve, and right tibial nerve). By way of example only, the user may change one or more stimulation settings of each peripheral nerve by first selecting one of the stimulation site tabs 264 .
Selecting one of the stimulation site tabs 264 will open a control window 265 , seen in FIG. 18 , from which various parameters of the SSPE manual test may be adjusted according to user preference. By way of example only, FIG. 18 is an illustration of an onscreen display for the SSEP manual test settings of the left ulnar nerve stimulation site. The highlighted “Left Ulnar Nerve” stimulation site tab 264 and the pop-up window title 266 indicate that adjusting any of the settings will alter the stimulation signal delivered to the left ulnar nerve. Multiple adjustment buttons are used to set the parameters of the stimulation signal. According to one example, the stimulation rate may be selected from a range between 2.2 and 6.2 Hz, with a default value of 4.7 Hz. The amplitude setting may be increased or decreased in increments of 10 mA using the amplitude selection buttons 270 labeled (by way of example only) “+10” and “−10”. More precise amplitude selections may be made by increasing or decreasing the amplitude in increments of 1 mA using the amplitude selection buttons 272 labeled (by way of example only) “+1” and “−1”. According to one example, the amplitude may be selected from a range of 1 to 100 mA with a default value of 10 mA. The selected amplitude setting is displayed in box 274 . The pulse width setting may be increased or decreased in increments of 50 μsec using the width selection buttons 276 labeled “+50” and “−50”. According to one example, the pulse width may be selected from a range of 50 to 300 μsec, with a default value of 200 μsec. The precise pulse width setting 278 is indicated in box 278 . Polarity controls 280 may be used to set the desired polarity of the stimulation signal. SSEP stimulation may be initiated at the selected stimulation settings by pressing the SSEP stimulation start button 284 labeled (by way of example only) “Start Stim.” Although stimulation settings adjustments are discussed with respect to the left ulnar nerve, it will be appreciated that stimulation adjustments may be applied to the other stimulation sites, including but not limited to the right ulnar nerve, and left and right tibial nerve. Alternatively, as described below, the system 10 may utilize an automated selection process to quickly determine the optimal stimulation parameters for each stimulation channel.
In order to monitor the health of the spinal cord with SSEP, the user must be able to determine if the responses to the stimulation signal are changing. To monitor for this change a baseline is determined, preferably during set-up. This can be accomplished simply by selecting the “set as baseline” button 298 next to the “start stim” button 284 on the setting screen illustrated in FIG. 4 . Having determined a baseline recording for each stimulation site, subsequent monitoring may be performed as desired throughout the procedure and recovery period to obtain updated amplitude and latency measurements.
FIG. 5 depicts an exemplary screen display for Manual mode of the SSEP monitoring function. A mode indicator tab 290 on the test menu 204 indicates that “SSEP Manual” is the selected mode. The center result area 201 is divided into four sub areas or channel windows 294 , each one dedicated to displaying the signal response waveforms for one of the stimulation nerve sites. The channel windows 294 depict information including the nerve stimulation site 295 , and waveform waterfalls for each of the recording locations 291 - 293 . For each stimulated nerve site, the system 10 displays three signal response waveforms, representing the measurements made at three different recording sites. By way of example only, the three recording sites are a peripheral 291 (from a peripheral nerve proximal to the stimulation nerve), subcortical 292 (spine), and cortical 293 (scalp), as indicated for example in Table 5 above. Each section may be associated with a pictorial icon, illustrating the neural/skeletal structure. Although SSEP stimulation and recording is discussed with respect to the nerve stimulation site and the recording sites discussed above, it will be appreciated that SSEP stimulation may be applied to any number of peripheral sensory nerves and the recording sites may be located anywhere along the nervous system superior to the spinal level at risk during the procedure.
During SSEP modes (auto and manual), a single waveform response is generated for each stimulation signal run (for each stimulation channel). The waveforms are arranged with stimulation on the extreme left and time increasing to the right. By way of example, the waveforms are captured in a 100 ms window following stimulation. The stimulation signal run is comprised of a predefined number of stimulation pulses firing at the selected stimulation frequency. By way of example only, the stimulation signal may include 300 pulses at a frequency of 4.7 Hz. A 100 ms window of data is acquired on each of three SSEP recording channels: cortical, subcortical, and peripheral. With each successive stimulation on the same channel during a stimulation run, the three acquired waveforms are summed and averaged with the prior waveforms during the same stimulation run for the purpose of filtering out asynchronous events such that only the synchronous evoked response remains after a sufficient number of pulses. Thus, the final waveform displayed by the system 10 represents an averaging of the entire set (e.g. 300 ) of responses detected.
With each subsequent stimulation run, waveforms are drawn slightly lower each time, as depicted in FIGS. 5-8 , until a total of four waveforms are showing. After more than four stimulation runs, the baseline waveform is retained, as well as the waveforms from the previous four stimulation runs. Older waveforms are removed from the waveform display. According to one embodiment, different colors may be used to represent the different waveforms. For example, the baseline waveforms may be colored purple, the last stimulation run may be colored white, the next-to-last stimulation run may be colored medium gray, and the earliest of the remaining stimulation runs may be colored dark gray.
According to one example, the baseline and the latest waveforms may have markers 314 , 316 placed indicating latency and amplitude values associated with the waveform. The latency is defined as the time from stimulation to the first (earliest) marker. There is one “N” 314 and one “P” 316 marker for each waveform. The N marker is defined as the maximum average sample value within a window and the P value is defined as the minimum average sample value within the window. The markers may comprise cross consisting of a horizontal and a vertical line in the same color as the waveform. Associated with each marker is a text label 317 indicating the value at the marker. The earlier of the two markers is labeled with the latency (e.g. 22.3 ms). The latter of the two markers is labeled with the amplitude (e.g. 4.2 uV). The amplitude is defined as the difference in microvolts between average sample values at the markers. The latency is defined as the time from stimulation to the first (earliest) marker. Preferably, the markers are placed automatically by the system 10 (in both auto an manual modes). In manual mode, the user may select to place (and or move) markers manually.
Further selecting one of the channel windows 294 will zoom in on the waveforms contained in that window 294 . FIG. 22 is an example illustration of the zoom view achieved by selecting one of the channel windows 294 . The zoom view includes waveforms 291 - 293 , the baseline waveform, markers 314 and 316 , and controls for moving markers 318 and waveform scaling 332 . Only the latest waveform is shown. The “Set All as Baseline” button 310 will allow the user to set (or change) all three recorded waveforms as the baselines. Additionally, baselines may be set (or changed) individually by pressing the individual “Set as Baseline” buttons 312 . Furthermore, the user may also move the N marker 314 and P markers 316 to establish new measurement points if desired. Direction control arrows 318 may be selected to move the N and P markers to the desired new locations. Alternatively, the user may touch and drag the marker 314 , 316 to the new location. Utilizing the waveform controls 332 the user may zoom in and out on the recorded waveform.
Referencing FIGS. 9-12 , Automatic SSEP mode functions similar to Manual SSEP mode except that the system 10 determines the amplitude and latency values and alerts the user if the values deviate. FIG. 9 shows, by way of example only, an exemplary setup screen for the SSEP Automatic mode. In similar fashion to the setup screen previously described for the SSEP Manual mode, the user may toggle between Manual mode and Automatic mode, select a stimulation rate, and change one or more stimulation settings. By way of example only, the user may change one or more stimulation settings of each peripheral nerve by first selecting one of the stimulation site tabs 264 , as described above with reference to Manual mode and FIG. 4 . According to one example, the stimulation rate may be selected from a range between 2.2 and 6.2 Hz, with a default value of 4.7 Hz, the amplitude may be selected from a range of 1 to 100 mA, with a default value of 10 mA, the pulse width may be selected from a range of 50 to 300 μsec, with a default value of 200 μsec.
In Automatic mode, the surgical system 10 also includes a timer function which can be controlled from the setup screen. Using the timer drop down menu 326 , the user may set and/or change a time interval for the timer application. There are two separate options of the timer function: (1) an automatic stimulation on time out which can be selected by pressing the auto start button 322 labeled (by way of example only) “Auto Start Stim when timed out”; and (2) a prompted stimulation reminder on time out which can be selected by pressing the prompt stimulation button 324 labeled (by way of example only) “Prompt Stim when timed out”. After each SSEP monitoring episode, the system 10 will initiate a timer corresponding to the selected time interval and, when the time has elapsed, the system will either automatically perform the SSEP stimulation or a stimulation reminder will be activated, depending on the selected option. The stimulation reminder may include, by way of example only, any one of, or combination of, an audible tone, voice recording, screen flash, pop up window, scrolling message, or any other such alert to remind the user to test SSEP again. It is also contemplated that the timer function described may be implemented in SSEP Manual mode.
FIGS. 10-12 depict exemplary onscreen displays for Automatic mode of the SSEP function. According to one embodiment, the user may select to view a screen with only alpha-numeric information ( FIG. 25 ) and one with alpha-numeric information and recorded waveforms ( FIG. 24 ). A mode indicator tab 290 indicates that “SSEP Auto” is the selected mode. A waveform selection tab 330 allows the user to select whether waveforms will be displayed with the alpha-numeric results. In similar fashion to the onscreen displays previously described for the SSEP Manual mode, the system 10 includes a channel window 294 for each nerve stimulation site. The channel window 294 may display information including the nerve stimulation site 295 , waveform recordings, and associated recording locations 291 - 293 (peripheral, sub cortical, and cortical) and the percentage change between the baseline and amplitude measurements and the baseline and latency measurements. By way of example only, each channel window 294 may optionally also show the baseline waveform and latest waveform for each recording site. In the event the system 10 detects a significant decrease in amplitude or an increase in latency, the associated window may preferably be highlighted with a predetermined color (e.g. red) to indicate the potential danger to the surgeon. Preferably, the stimulation results are displayed to the surgeon along with a color code so that the user may easily comprehend the danger and corrective measures may be taken to avoid or mitigate such danger. This may for example, more readily permit SSEP monitoring results to be interpreted by the surgeon or assistant without requiring dedicated neuromonitoring personnel. By way of example only, red is used when the decrease in amplitude or increase in latency is within a predetermined unsafe level. Green indicates that the measured increase or decrease is within a predetermined safe level. Yellow is used for measurements that are between the predetermined unsafe and safe levels. By way of example only, the system 10 may also notify the user of potential danger through the use of a warning message 334 . Although the warning message is in the form of a pop-up window, it will be appreciated that the warning may be communicated to the user by any one of, or combination of, an audible tone, voice recording, screen flash, scrolling message, or any other such alert to notify the user of potential danger
With reference to FIG. 12 at any time during the procedure, a prior stimulation run may be selected for review. This may be accomplished by, for example, by opening the event bar 208 and selecting the desired event. Details from the event are shown with the historical details denoted on the right side of the menu screen 302 and waveforms shown in the center result screen. Again, the user may chose to reset baselines for one or more nerve stimulation sites by pressing the appropriate “Set As Baseline” button 306 . In the example shown, the system 10 illustrates the waveform history at the 07:51 minute mark which is denoted on the right side of the menu screen 302 . Prior waveform histories are saved by the surgical system 10 and stored in the waveform history toolbar 304 . The describe only in relation to the SSEP Auto function it will be appreciated that the same features may be accessed from SSEP Manual mode, the user may choose to set a recorded stimulation measurement as the baseline for each nerve stimulation site by pressing the “Set As Baseline” button 306 . By way of example only, the system 10 will inform the user if the applicable event is already the current baseline with a “Current Baseline” notification 308 .
The waveform marker placement algorithm of the present invention will now be described in detail. According to a broad aspect, the waveform marker placement algorithm takes an iterative approach to identifying negative (N) and positive (P) peaks within a waveform and identifying where the N and P latency markers should be placed based on static and dynamic search windows. FIG. 13 is a flowchart of the general steps involved in waveform marker placement in accordance with the algorithm of the present invention. For the purposes of illustration, the algorithm 400 encompasses the waveform data processing and marker search steps for an individual waveform from a single channel. It is contemplated that these steps may be performed on multiple channels either in series or simultaneously. For purposes of illustration, the algorithm is 400 split into three sub-algorithms: a waveform processing algorithm 404 , a predictive waveform morphology search algorithm 406 ; and a waveform marker location algorithm 408 and these sub-algorithms will be designated as such throughout this disclosure. As depicted in the flowchart in FIG. 13 , at step 402 , the algorithm processor receives a raw waveform 422 ready for processing; at step 404 , the waveform is processed to determine what can and cannot be a possible neurophysiologic response; at step 406 , the a predictive waveform morphology search is performed on the processed waveform to identify signals that match neurophysiologic waveform morphology criteria; at step 408 , a marker location search is performed on the waveform processed at step 408 to determine where N and P latency markers should be placed on the neurophysiologic signal, and at step 510 , the determined marker placement locations are displayed on the neurophysiologic response waveform on display 34 of control unit 12 .
Waveform Processing
FIGS. 14-20 detail the steps of the waveform processing sub-algorithm 404 in greater detail. For illustrative purposes, the waveform data set of FIG. 15 will be used, where appropriate, to illustrate the successive steps of the algorithm 400 and sub-algorithms 404 , 406 , 408 . At step 402 , the raw waveform data 422 is first passed into the algorithm processor. At step 412 , the raw waveform data is processed to determine the ascending and descending peaks within the waveform. According to one embodiment, the algorithm finds directional changes in the waveform trend from ascending to descending and descending to ascending. The diagram of FIG. 16 illustrates how the peaks would be determined after the completion of step 412 and how the peaks waveform 424 compares to the original (raw) waveform 422 .
The peaks information obtained at step 412 may then be used to identify noise spikes and calculate a noise level for the waveform. According to one embodiment, the noise level may be calculated by finding signal rise transitions that are less than a given sample threshold, adding up their amplitudes and multiplying that result by the time duration of the noise spike, and dividing that number by the total number of samples used in the calculation.
FIG. 17 depicts step 414 and details how the noise average is calculated on the waveform data set of FIG. 15 . For purposes of illustration, a signal threshold of 1.5 msec is selected. As shown in FIG. 17 , there are three noise samples that would qualify with a duration of less than 1.5 msec. Noise Sample 1 has an amplitude of 1.0 μV and a duration of 1.0 msec; Noise Sample 2 has an amplitude of 0.5 μV and a duration of 1.0 msec; and Noise sample 3 has an amplitude of 5.0 μV and a duration of 1.0 msec. Multiplying the amplitude of each sample by its respective duration gives a noise sample sum of 6.5. The noise sample is divided by the time base (30 msec) and results in a noise average of 0.217. According to one or more implementations, the algorithm may exclude an early latency portion of the waveform from the noise calculation to disqualify any stimulus artifact present at the onset of the waveform from entering into the noise average calculation.
To prevent small noise peaks as being considered as the end of a detected signal (or perhaps the beginning of a new signal), an averaged waveform may be found (step 416 ). To find the averaged waveform, according to one embodiment, the peaks waveform obtained at step 412 may be used and each of the line segments may be bisected to find the averaged waveform. FIG. 18 shows the averaged waveform 426 as the bisection of the peaks waveform 424 . According to one embodiment, when a bisected line value falls in between two waveform indices (amplitude values) the prior lower of the two indices may be used. For illustrative purposes, if a point is to fall between index 4 and 5, the averaged point will be 4. If a point is to fall between index 4 and 6, the index for the averaged point will be 5). Once the small noise peaks are minimized, the averaged waveform 426 may then be processed at step 418 to ascertain its ascending and descending peaks which allows the algorithm to determine where the true peaks are by eliminating possible noise components ( FIG. 19 ).
At step 420 , the signals are identified based on an averaged peak comparison. As a threshold matter, any potential signal must first meet minimum rise time and minimum signal amplitude values to be qualified as a signal. For example, according to one embodiment, any potential signal of less than 0.5 μV in amplitude and an ascending or descending transition time of less than 0.5 msec may be ignored by the algorithm. As depicted in FIG. 20 , the peaks of the averaged waveform 424 are compared against the peaks 422 discovered in the raw waveform to determine where those averaged peaks 424 are located in the original raw waveform 422 . It is to be appreciated that it is important to determine where the averaged peaks are in the original waveform since the original waveform is what is plotted for display to the user. For illustrative purposes only, the peaks in the original waveform are designated as numbers 1-6 and the peaks in the averaged waveform are designated as numbers 1′-6′.
Predictive Waveform Morphology Search
With respect to FIGS. 21-26 , the predictive waveform morphology sub-algorithm 406 will now be discussed in greater detail. With the raw waveform processed and signals that cannot be considered as likely neurophysiologic signals excluded, the algorithm proceeds to step 406 and searches each waveform for a particular morphology based on any number of searchable parameters. This particular morphology may include certain characteristics of an SSEP response. By way of example, the searchable parameters may be: signal rise type, minimum and maximum signal rise times, minimum and maximum signal amplitudes, and minimum signal to noise ratio as shown in the flowchart of FIG. 21 . Each of these searchable parameters will be discussed in turn below.
The predictive waveform morphology sub-algorithm 406 may classify all signals within a waveform as ascending or descending (step 428 ). The algorithm 406 can search for either ascending or descending signals when the rise type can be predicted as well as when the rise type cannot be predicted. In the example waveform of FIG. 22 , the signals are classified based on rise type according to the results of Table 2:
TABLE 2
Rise Type
Results
Ascending
B&C
D&E
Descending
A&B
C&D
E&F
The predictive waveform morphology sub-algorithm 406 may then classify all signals within a waveform based on the signal rise time (step 430 ). The signal rise time is the measure of the entire time an ascending or descending signal trends in that direction. The minimum signal rise time defines the minimum time this trend must take before it is considered a valid neurophysiologic signal. The maximum signal rise time defines the maximum time this trend may take before it is considered an invalid signal. These considerations may help discount noise spikes from being classified as valid signals.
Though the signal is a single ascending or descending transition, the minimum signal rise time considers the ascending and descending components that make up each signal. FIG. 23 illustrates how each ascending or descending signal has an opposite component. Both the actual signal and its opposite component are used (individually) to determine whether the signal has exceeded the minimum and maximum rise times.
The predictive waveform morphology sub-algorithm 406 may then classify all signals within a waveform based on minimum and maximum signal amplitude (step 432 ). The signal amplitude is the amplitude value change between the positive and negative peaks of a signal. ( FIG. 24 ) The minimum signal amplitude is the amplitude required to qualify a given signal to be considered for marker placement. The maximum signal amplitude is the maximum amplitude value a signal can be to be considered for marker placement.
The predictive waveform morphology sub-algorithm 406 may then classify all signals based on the signal to noise ratio (step 434 ). The Signal to Noise Ratio (SNR) is calculated by taking the amplitude of the signal and dividing it by the calculated noise of the waveform. The minimum SNR defines the minimum SNR required to qualify a given signal to be considered for marker placement.
Thus, the identification and rejection of signal to be classified as a valid neurophysiologic signal can be made utilizing a set of predictive morphology search parameters. FIGS. 25 and 26 show an identified valid neurophysiologic signal (response) 440 and a rejected signal 442 , respectively, based on the example predictive morphology search parameters of Table 3:
TABLE 3 Parameter Value Signal rise type Descending Minimum signal rise time 1.5 msec Maximum signal rise time 15.0 msec Minimum signal amplitude 0.5 μA Maximum signal amplitude 10.0 μA Minimum SNR 2.2
Specifically, the waveform of FIG. 25 is a descending signal segment with a rise time of 9 msec, signal amplitude of 11.5 μV, and a signal to noise ratio of 3.42. each of these values meet the parameters set forth in Table 3, so the identified signal 440 qualifies as a valid neurophysiologic signal and a candidate for marker placement in the waveform marker placement sub-algorithm 408 as will be discussed in greater detail below. The waveform of FIG. 26 is a descending signal segment of a signal rise time of 1 msec, signal amplitude of 5 μV, and a signal to noise ratio of 1.49. Because the minimum signal rise time and the signal to noise ratio in this example are lower than that required by the parameters of Table 3, the signal 442 will be rejected and will not be processed further at step 408 .
Waveform Marker Location Search
With the signals processed and valid neurophysiologic signals identified as set forth above, the location of where to place waveform markers on the neurophysiologic signal may commence. FIGS. 27-31 depict the waveform marker location sub-algorithm 408 according to one embodiment. The waveform marker location sub-algorithm 408 applies search window criteria to determine which aspect of a signal that is most likely to be the neurophysiologic response. According to one embodiment, for determining the likely signal, the algorithm will search through a predefined number of signal candidates and determine which one is the largest. For example, if the search value is five, the algorithm will search through the first five signal candidates and determine which has the largest amplitude change. If there are less than five signal candidates, the algorithm will search through all of the candidates to determine the likely signal. It is contemplated that the algorithm possesses a plurality of search types that are variable and configurable.
FIG. 27 is a flowchart depicting the steps of the waveform marker location sub-algorithm 408 in greater detail. At step 444 , a waveform containing an identified signal from step 436 (above) but possessing no waveform identification markers is entered into the sub-algorithm processor. At step 446 , a search is performed to find a likely neurophysiologic response signal based on whether or not a reference signal (or “baseline”) is available. Next, the algorithm searches to ascertain whether a reference signal is available to compare it to (step 448 ).
If a reference signal is available, a reference search is performed at step 450 . According to one embodiment, if a reference signal is found at step 452 , that reference signal's marker placement values can be used to create a targeted search window based on configurable parameters. By way of the example in FIG. 28 , waveform 1 (baseline waveform) had latency markers placed at 20 msec and 25 msec. Using this as a reference, the search windows for waveform 2 (current waveform) are 18-24 msec and 22.5-30 msec based on a +20% and -10% reference window. Note that these are examples and in any implementation, the actual reference search window parameters can be variable. As can be seen in FIG. 28 , a likely signal is found within this reference window. Next, markers may be set based on this likely signal at step 458 as will be discussed below. One of skill in the art will readily appreciate that performing a reference search of this type allows the identified signals in the current waveform to be processed much more quickly as signals that start or end outside of the reference window are ignored.
The reference search may also take into account the signal rise type of the marked signal of the baseline when searching. By way of illustration, if the reference's marked signal is descending, then the reference search will only qualify descending signals as valid. With SSEP, the algorithm uses a predictive morphology (a descending cortical signal for instance) to search. However, if the user decides to mark an ascending signal instead of the predicted descending signal as in the prior example, the reference will “learn” from the user's actions and search for an ascending signal to match that of the signal marked on the baseline according to one embodiment.
When searching for the likely response signal within a waveform, the algorithm attempts to locate a signal that exceeds the noise level by a predefined value (a SNR value of 2.2, for example.). As depicted in the flowchart of FIG. 27 , if a likely signal is not found at step 452 , a second pass is performed using a slightly lower SNR value (step 454 ). For example, if the first pass fails to find a likelysignal at an SNR of 2.2, a second pass will look for a signal at an SNR 10% lower than the original SNR (or 1.98). If a likely signal is found as a result of this second pass (step 456 ), markers will be set based on this likely signal (step 458 ). However, if a likely signal is not found as a result of this second pass (step 456 ) i.e., if a signal meeting the search criteria cannot be found matching the baseline), the marker latency values for the search (at step 458 ) will be the same as those for the original reference (baseline) signal by “dropping the amplitude value” from one recording into the next. FIG. 29 illustrates no valid, matching signal in waveform 2 (current waveform) when compared to waveform 1 (baseline/reference) so the markers are “dropped” to the same time-based locations on the waveform 2 as waveform 1.
Returning back to step 448 , if it is determined that there is no reference signal available (perhaps because a baseline has yet to be established), the algorithm may search without a reference (step 460 ) using one or more search types. The first type of search executable by the algorithm 408 is a default window search which uses configurable parameters to define windows in which a valid neurophysiologic signal can be included. In one embodiment, the default window search provides a time-based window in which to search for the likely signal. The beginning and end of the window for each of the markers to be searched for can be configured based on clinical data. For example, a SSEP response comprises somewhat predictable negative and positive (N and P) latencies. These latency values can be bracketed by the beginning and end windows using the default window search. If a likely signal is found using the default reference search, the markers may be placed on that likely signal at step 466 . However, if a likely signal is not found, a second pass is performed using a slightly lower SNR value (step 464 ). For example, if the first pass fails to find a signal at an SNR of 2.2, a second pass will look for a signal at an SNR 10% lower than the original SNR (or 1.98). If a likely signal is found as a result of this second pass, the algorithm will set markers based on this likely signal (step 466 ). However, if no likely signal is found, the algorithm may default and place the markers at 0 msec.
The results of the default window search can be further narrowed by optionally performing a comparative search. The comparative search capitalizes on the fact that waveforms can be related to one another and when they are, the algorithm 406 may search for the likely signal in each waveform in a pre-defined order using any likely signals found to further tighten the search windows of subsequent searches. According to one embodiment, the comparative search allows the algorithm to use the identified marker locations from associated waveforms to help narrow the default search window. By way of example only, with SSEPs, three recording channels often are used (e.g. a cortical channel, a subcortical channel, and a peripheral channel). The relationship between the waveforms of each of the three channels is that none of the marked responses overlap because the latencies for each is different: the peripheral channel having the shortest latency, the subcortical channel having an intermediate latency, and the cortical channel having the longest latency (see FIG. 30 ). Using this relationship, the algorithm can find one or two bounding waveform response signals and use them to determine a smaller search window for the third waveform response as will be explained in greater detail below.
FIG. 31 depicts a flowchart highlighting the steps of the comparative search function according to one embodiment. Step 472 , a waveform containing an identified signal from step 436 (above) but possessing no waveform identification markers enters a first pass into the sub-algorithm processor. The algorithm first searches for cortical SSEP responses at step 474 and attempts to place cortical waveform markers if possible. At step 476 , the algorithm will attempt to find the sub-cortical responses and place subcortical waveform markers and will incorporate the cortical marker latency values to represent an end boundary for the subcortical latency search window. At step 478 , the algorithm will next attempt to find the peripheral responses and will incorporate either or both the cortical and sub-cortical marker latency values as an end boundary for the peripheral latency search window.
At step 480 , the algorithm determines whether all cortical, sub-cortical, and peripheral response were found. If yes, the marker search will be deemed complete at step 494 . If no, however, the algorithm proceeds to step 482 and performs a second pass using a reduced SNR search similar to that described above. Following the reduced SNR search, the algorithm will search for cortical responses (step 482 ). If a cortical response was found, the marker is placed, the algorithm proceeds to step 486 . If no, the algorithm uses the sub-cortical and peripheral latency values to help narrow the cortical latency search window if possible (step 484 ). After the cortical signal has been processed, the algorithm proceeds to step 486 and will search for subcortical responses. If a subcortical response was found, the marker is placed and the algorithm proceeds to step 490 . If no, the algorithm uses the cortical and peripheral latency values to help narrow the subcortical latency search window if possible 488 . After the subcortical signal has been processed, the algorithm proceeds to step 490 and will search for peripheral responses. If a peripheral response was found, marker is placed and the algorithm proceeds to step 494 . If no, the algorithm uses the cortical and subcortical latency values to help narrow the peripheral latency search window if possible. After the peripheral response has been processed, the marker search is complete 494 . It is to be appreciated that the default window search and comparative search are preferably used to determine a baseline/reference response. From there, the reference search is preferably used throughout the rest of the surgical procedure to automatically place waveform markers.
While this invention has been described in terms of a best mode for achieving this invention's objectives, it will be appreciated by those skilled in the art that variations may be accomplished in view of these teachings without deviating from the spirit or scope of the present invention. For example, the present invention may be implemented using any combination of computer programming software, firmware or hardware. As a preparatory step to practicing the invention or constructing an apparatus according to the invention, the computer programming code (whether software or firmware) according to the invention will typically be stored in one or more machine readable storage mediums such as fixed (hard) drives, diskettes, optical disks, magnetic tape, semiconductor memories such as ROMs, PROMs, etc., thereby making an article of manufacture in accordance with the invention. The article of manufacture containing the computer programming code is used by either executing the code directly from the storage device, by copying the code from the storage device into another storage device such as a hard disk, RAM, etc. or by transmitting the code on a network for remote execution. As can be envisioned by one of skill in the art, many different combinations of the above may be used and accordingly the present invention is not limited by the specified scope. | The present invention relates to a system and methods generally aimed at surgery. More particularly, the present invention is directed at a system and related methods for performing surgical procedures and assessments involving the use of neurophysiology. | 0 |
This application is a divisional of copending application Ser. No. 014,655, filed on Feb. 13, 1987, which is a divisional of copending application Ser. No. 813,698, filed on Dec. 27, 1985, and now U.S. Pat. No. 4,712,392.
BACKGROUND OF THE INVENTION
(i) Field of the Invention
The present invention relates to a dry cleaning method wherein at least two kinds of solvents are used.
(ii) Description of the Prior Art
For the understanding of a conventional dry cleaning technique, a dry cleaning process of using solvents other than turpentine will be described in reference to FIG. 6 in which the conventional dry cleaning system is shown. First, clothes 2 are thrown into a treating tank 10 by opening a door 1, and after the door 1 has been shut, the operation of the dry cleaner is begun. Afterward, a cleaning treatment generally makes progress in the following order.
(1) A solvent 4 is pumped up from a solvent tank 3 via a valve 5 by means of a pump 6 and is delivered in a predetermined amount to the treating tank 10 through a route consisting of a valve 7 and a filter 8 or a route consisting of a valve 9.
(2) A treating drum 11 is slowly rotated, and the solvent 4 is then circulated through a circuit consisting of the treating tank 10, a button trap 12, a valve 13, the pump 6, the valve 7, the filter 8 or the valve 9 in order to wash the clothes 2.
(3) The solvent 4 is discharged through a route consisting of the treating tank 10, the button trap 12, the valve 13, the pump 6, a valve 14 and a distiller 15. Afterward, the treating drum 11 is rotated at a high speed to centrifuge the solvent 4 present in the clothes 2, and the centrifuged solvent 4 is then discharged in like manner.
(4) The preceding processes (1) and (2) are repeated.
(5) The solvent 4 is discharged to the solvent tank 3 through the treating tank 10, the button trap 12, the valve 13 and the valve 5. Afterward, the treating drum 11 is rotated at a high speed to centrifuge the solvent 4 present in the clothes 2, and the centrifuged solvent 4 is discharged therefrom.
(6) The treating drum 11 is slowly rotated again, and air is circulated in the direction of an arrow 20 between the treating tank 10 and a recovery air duct 19 consisting of a fan 16, an air cooler 17 and an air heater 18, whereby the clothes 2 are dried. A solvent gas vaporized from the clothes 2 is condensed in an air cooler 17, is then delivered to a water separator 22 via a recovery passage 21, and is afterward introduced into a clean tank 24 through a solvent pipe 23.
(7) When drying has been over, dampers 25, 26 are opened as depicted by dotted lines in the drawing, and fresh air is taken in through the damper 25. Further, the uncondensed solvent gas which has not been recovered in the air cooler 17 is discharged through the damper 26 in order to take away the odor of the solvent in the clothes 2.
(8) The solvent 4 forwarded to the distiller 15 in the preceding process (3) is evaporated, and is then condensed in a condenser 27. The condensed solvent 4 is introduced into the clean tank 24 through the water separator 22 and the solvent pipe 23 and is then returned to the solvent tank 3 over an overflow partition 28. In this connection, the water separated by the water separator 22 is discharged from the system through a water pipe 29.
Another dry cleaning process of using turpentine (an oil series solvent) is shown in FIGS. 7 and 8. In general, the turpentine dry cleaning apparatus is composed of a washing and desolvating tank 100 shown in FIG. 7, which is similar to the treating tank shown in FIG. 6, and a drying exclusive tank 200 in FIG. 8 (which is called a tumbler). In the washing and desolvating tank 100, the same procedure as the above-mentioned washing processes (1), (2) and (5) of using the other solvent is taken, whereby all the processes are over. Incidentally, the turpentine dry cleaning method generally contains no distillation process, and in many cases, the purification of the solvent 4 is carried out by using a filter 8a which is packed with an aliphatic acid adsorbent such as porous alumina and a decolorant such as activated carbon.
Next, the desolvated clothes 2 are taken out by opening the door 1, and after the opening of a door 1a of the tumbler shown in FIG. 8, they are thrown into a treating tank 10a. In the tumbler, the outside air 20a is taken in through an inlet duct 19a by a fan 16 and is heated by an air heater 18, and the heated air is then delivered to the treating tank 10a. The solvent 4 in the clothes 2 is evaporated and is then discharged from the system (to the outdoors) through an outlet duct 19a, whereby drying is over.
The general dry cleaning processes of using various solvents have now been described above, but at present, in the dry cleaner in which these solvents can be employed, the washing and drying method of using each solvent has been independently employed, whatever solvents are selected.
Table 1 compares typical physical properties of the solvents often used presently. Further, Table 2 compares features, restrictions, faults and the like of the solvents regarding the dry cleaning on the basis of their physical properties shown in Table 1.
In order to apply to presently diversified materials, processings and forms of clothes, it is necessary to use two kinds of perchloroethylene dry cleaner and Flon 113 dry cleaner, or three kinds of above cleaners and 1,1,1-trichloroethane dry cleaner. If two or more kinds of solvents are used in the conventional apparatus, purchase funds, occupation space, volume of facilities, and the like will be increased, and maintenance work will be complicated. These facts are of great concern to the cleaning trade.
FIG. 5 compares general washing and drying processes in the cases of using perchloroethylene, 1,1,1-trichloroethane, turpentine (oil series) and Flon 113 which are now widely employed. As shown in this drawing, all the methods, except for the Flon 113 method, take about 50% of the whole treatment time to accomplish drying, which fact is an obstacle to recent needs of shortening the treatment time. In addition thereto, the dry tumbling for a long period of time has a bad effect on the clothes at times, and, for example, hairiness and shrinkage of the clothes tend to be caused thereby.
TABLE 1______________________________________ Boiling Specific point gravity Ignition (°C.) (g/cc) KB value point______________________________________1,1,1-Trichloro- 74 1.35 124 Not burntethanePerchloroethane 121 1.62 90 Not burntFuron R113 47.5 1.58 31 Not burntTurpentine 150-200 0.8 31 38° C.(oil series)______________________________________
The KB values in Table 1 are scales for representing relative dissolving powers of the solvents.
TABLE 2
1,1,1-Trichloroethane:
(Features)
Dissolving power and washing power are great.
Reverse contamination scarcely occurs.
Boiling point is relatively low.
Suitable for men's suits, wool knitwears, etc.
Low-temperature drying is possible.
(Restrictions and faults)
Unsuitable for urethane-processed articles, recently commercially available delicate clothes containing adhesive materials, pigments, prints, specific resins, gums, etc.
Main portion of used apparatus is made from stainless steel.
(Remarks)
Recovery of activated carbon is a little hard (stability of recovered solvent is poor).
In the last several years, market grows rapidly.
Perchloroethylene:
(Features)
Dissolving power and washing power are next largest to 1,1,1-trichloroethane.
Having the next highest boiling point to turpentine.
Suitable for men's suits, wool knitwears, etc.
(Restrictions and faults)
Substantially ditto.
Since drying temperature is a little higher, attention must be paid to materials which are low in heat resistance.
(Remarks)
Of synthetic solvents, the most prevalent.
Main portion of used apparatus can be made from plated iron.
Flon 113:
(Features)
Dissolving power and washing power are small.
Having lower boiling point.
Applicable to most clothing materials (suitable for delicate clothes).
Low-temperature and short-time drying is possible.
(Restrictions and faults)
Because of weak washing power, removal of soils are difficult.
Solvent recovering technique by freezing or by use of activated carbon is necessary.
Main portion of used apparatus is made from stainless steel.
(Remarks)
Most expensive.
Market grows slowly.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a dry cleaning method which can be applied to varied materials, processings, and forms of clothes.
Still another object of the present invention is to provide a dry cleaning method by which there can be overcome problems such as hairiness and shrinkage due to a long-term drying in a conventional dry cleaning process.
The above-mentioned objects are as follows:
The method of the present invention is carried out with a dry cleaning apparatus in which tanks for exclusively receiving at least two kinds of solvents which are soluble in each other, one treating tank connected to the tanks, and a fractionating device, connected to the tanks and the treating tank, for recovering the two or more kinds of solvents by fractional distillation. Exclusive filters for the respective solvents are provided wherein a common filter or a multi-filter device composed of both the filters is disposed between the tanks and the treating tank. The two or more kinds of solvents are used independently so that washing is carried out.
The dry cleaning method of the present invention comprises the steps of providing tanks for exclusively receiving at least two kinds of solvents which are soluble in each other, connecting one treating tank to the tanks, providing a fractionating device, connected to the tanks and the treating tank, recovering the two or more kinds of solvents by fractional distillation through the use of the fractionating device, providing exclusive filters for the respective solvents through the use of a common filter or a multi-filter device composed of both the filters which is disposed between the tanks and the treating tank,; and using the two or more kinds of solvents independently so that washing is carried out.
Also disclosed in this application is a dry cleaning method in which a dry cleaner using organic solvents such as perchloroethylene, 1,1,1-trichloroethane, turpentine (oil series) and the like, the previously used solvent is replaced with another solvent which is soluble therein and has a lower boiling point, for example, Flon 113 or 11, during washing or immediately before drying in order to thereby shorten a drying period of time.
The present invention thus constituted, provides the following effects:
(I) Two or more solvents can be used in optional ratios in one dry cleaner, and thus the most proper washing method can be chosen for the greater part of materials, processings and morphologies of clothes. Further, it is possible to remarkably reduce troubles (faulty washing, creases, shrinkages, discoloration, deformation, removal of adhesive materials, and the like) regarding a washing technique. Also in points of occupation space, fund for facilities, volume of facilities and maintenance cost, the present invention has great advantages.
(II) According to the dry cleaning method of the present invention, a drying time can be shortened noticeably and a bad influence of tumbling on clothes can be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a systematic view illustrating a first embodiment of a dry cleaning apparatus regarding the present invention;
FIG. 2 is a circuit diagram illustrating a fractionating system used in the first embodiment of the present invention;
FIG. 3 is a circuit diagram illustrating a usage of specific filters containing a deoxidizer and a decolorant which are often used in the first embodiment of the present invention in which turpentine is employed;
FIG. 4 is a diagram showing a relation between a drying time and a solvent condensation recovery rate in an air cooler in a second embodiment of the present invention in which the apparatus in FIG. 1 is employed;
FIG. 5 is a comparative illustrative view of washing and drying processes by the use of various usual solvents such as perchloroethylene and the like;
FIG. 6 is a systematic view of a conventional dry cleaner; and
FIGS. 7 and 8 are illustrative views of a conventional dry cleaning process of using turpentine.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Now, preferable embodiments for the practice of the present invention will be described in accordance with accompanying drawings:
EMBODIMENT 1
FIGS. 1 to 3 show a first embodiment of the present invention. For simplification, these drawings exemplarily show exclusive solvent tanks for two kinds of solvents and a fractionating device or a filter structure, but needless to say, they can serve for three or more kinds of solvents in all the same volume.
With regard to differences between a fundamental embodiment of the present invention shown in FIG. 1 and the above-mentioned constitution (the conventional method) shown in FIG. 6, a first difference is that a first solvent receiving tank 3 and a second solvent receiving tank 3a are disposed independently of each other and they are provided with exclusive valves 5 and 5a, respectively.
A second difference therebetween is that valves 32, 32a which are adjustable in compliance with boiling points inherent in solvents or by a program control are disposed on a condensed solvent flow pipe 34 connecting to water separators 22, 22a; solvent pipes 23, 23a and water pipes 29, 29a are provided; and a safety valve 33 is additionally disposed on a condenser 27.
A third difference is that a recovery passage 21 extending from an air cooler 17 is connected to the water separator 22 or 22a via a valve 30 or 30a and is connected to a distiller 15 via a non-return valve 31.
Except for these three differences, the structure in FIG. 1 is about the same as in FIG. 6. It can be naturally conceived to exclusively provide a pump 6 for each solvent, but for simplification, one pump 6 is here used in common.
FIG. 2 shows a constitutional example of a condenser capable of completely recovering the two kinds of solvents by fractionation. A riser 36 on the distiller 15 (FIG. 1) is connected to a first condenser 27a in which a cooling coil 41 is disposed. A temperature of this cooling coil 41 is adjusted to a level equal to or 2° to 3° C. higher than a lower boiling point of the two solvents by means of a control system not shown. A gas pipe 37 is connected to the bottom of the condenser 27a and a liquid pipe 38 branches off from the gas pipe 37. This liquid pipe 38 is dipped in a tank 35 filled with a cooling water 40a in a low-temperature cooling coil 40 and is further connected to the water separator 22a (FIG. 1). The above-mentioned gas pipe 37 is connected to a second condenser 27b, where there is disposed the low-temperature cooling coil 40 which has been cooled to a temperature enough to condense the low boiling point solvent. Further, a liquid pipe 39 extends downward from the bottom of the condenser 27b and is connected to the water separator 22 (FIG. 1).
FIG. 3 is a constitutional example of specific filters containing a deoxidizer and a decolorant which have often been used in a turpentine (oil series) dry cleaning system. Filters 8a, 8a-1 and 8b in this drawing are all the especial filters, and these filters are equipped with exclusive valves 7a, 7a-1 and 7b and non-return valves 50, 50a, 50b, respectively. Further, these filters are connected to a pipe in parallel.
Next, reference will be made to a function of the embodiment thus constituted. First, in the case of separately using the two kinds of solvents without mixing them, washing and drying processes are much the same as in a conventional method (FIG. 6), and so a detailed description about them will be omitted here. It is however to be noted that opening and shutting of the valves 30 or 30a disposed on the recovery passage 21 extending from the air cooler 17 are controlled by the program control system (not shown) in response to the kinds of solvents so that the solvents 4, 4a may not be mixed with each other in the connected water separators 22, 22a and tanks 3, 3a.
Also with regard to the distillation, the opening and shutting of the valves 32, 32a disposed on the condensed solvent flow pipe 34 extending from the condenser 27 are controlled by the program control system (not shown) in compliance with the kinds of solvents, or alternatively these vavles 32, 32a are opened or shut by detecting a temperature of the solvent in the distiller 15 with the aid of a temperature sensor (not shown) in order to avoid mixing the solvents 4, 4a with each other. As a result, in both the cases of the drying and distillation, the solvents 4, 4a flow into the exclusive tanks 3, 3a, respectively. Incidentally, one distiller is disposed in this embodiment, but needless to say, plural exclusive distillers may be provided for the respective solvents.
Next, detailed reference will be made to the case where the two kinds of solvents are positively mixed and used in an optional ratio.
(1) The first solvent 4 is pumped up from the tank 3 via the valve 5 by means of the pump 6 and is delivered in a predetermined amount to the treating tank 10 through the valve 7 and the filter 8 or through the valve 9. Successively, the second solvent 4a is pumped up from the tank 3a via the valve 5a in like manner.
(2) A treating drum 11 is slowly rotated, and a mixed solvent (4+4a) is circulated through a circuit consisting of the treating tank 10, a button trap 12, a valve 13, the pump 6, the valve 7 and the filter 8 or the valve 9.
(3) The mixed solvent (4+4a) is discharged through a route consisting of the treating tank 10, the button trap 12, the valve 13, the pump 6, a valve 14 and the distiller 15. Afterward, the treating drum 11 is rotated at a high speed to centrifuge the solvent (4+4a) present in the clothes 2, and the centrifuged solvent (4+4a) is discharged in like manner.
(4) The preceding processes (1), (2) and (3) are repeated. Alternatively, after the preceding processes (1) and (2) have been repeated, the mixed solvent (4+4a) is discharged to a third tank (not shown) through the treating tank 11, the button trap 12, the valve 13 and the pump 6.
(5) The treating drum 11 is slowly rotated again, and air is circulated in the direction of an arrow 20 between the treating tank 10 and a recovery air duct 19 consisting of a fan 16, the air cooler 17 and an air heater 18, whereby the clothes 2 are dried. A solvent gas vaporized from the clothes 2 is condensed in the air cooler 17 and is delivered to the distiller 15 through the recovery circuit 21 containing the non-return valve 31.
(6) When drying has been over, dampers 25, 26 are opened as depicted by dotted lines in the drawing, and fresh air is taken in through the damper 25. Further, the uncondensed solvent gas which has not been recovered by the air cooler 17 is discharged through the damper 26 in order to take away the odor of the solvent in the clothes 2.
(7) The mixed solvent (4+4a) forwarded to the distiller 15 in the preceding processes (3), (4) and (5) is distilled at a lower boiling point (for example, of the solvent 4) of the respective solvents, and is caused to pass through a condenser 27. The mixed solvent condensed therein is then introduced into the water separator 22 via the valve 32 opened under a control of a distillation temperature sensor (not shown), and is further returned to the solvent tank 3 through a solvent pipe 23.
Next, as an amount of the solvent having the lower boiling point in the distiller 15 is reduced, a temperature of the mixed solvent progressively approaches a boiling point of the other solvent having a higher boiling point and the distillation of the latter begins. At this time, however, the distillation temperature sensor (not shown) operates in the same manner as described above, in order to open the valve 32a (the valve 32 is shut), thereby recovering the high boiling point solvent 4a in the tank 3a in the same manner as described above (a solvent of an intermediate component in the transition from the low boiling point solvent to the high boiling point solvent is as small as trace in experiments, and thus it has no problem in practice. In consequence, the intermediate solvent may be handled as the low or the high boiling point solvent).
Now, the fractional system shown in FIG. 2 will be briefly described. The low boiling point solvent 4 evaporated in the distiller 15 (FIG. 1) is, to begin with, introduced into the first condenser 27a, but it is not condensed therein, because a temperature of the cooling water in the cooling coil 41 is higher than the boiling point of the low boiling point solvent. Therefore, the latter is delivered through the gas pipe 37 to the second condenser 27b, wherein it is condensed by the low-temperature cooling coil 40, and the condensed solvent then runs into the water separator 22 via the liquid pipe 39. When the high boiling solvent begins to evaporate, the recovery of the solvent in the first condenser 27a becomes possible, and the condensed solvent runs into the water separator 22a through the liquid pipe 38. The tank 35 which has been filled with the cooling water 40a of the low-temperature cooling coil 40 serves to cool the liquid pipe 38 dipped in the cooling water 40a.
In the last place, with regard to the specific filer containing a deoxidizer and a decolorant which have often been used in the turpentine (oil series) dry cleaning system, its use example will be described briefly in reference to FIG. 3. In the case that washing is carried out by switching the two kinds of solvents so as to independently use them, the filters 8a-1 and 8b are used exclusively. For example, when the filter 8a-1 is employed for the first solvent 4, the valve 7a-1 alone is opened and the others are shut. The solvent 4 which has passed through the filter 8a-1 pushes the non-return valve 50a and runs into the treating tank 10 (FIG. 1).
In the case that the two kinds of mixed solvents are employed, the filter 8a alone is used in the same manner as described above so that the solvent components in the filters 8a-1, 8b may not be changed.
EMBODIMENT 2
This embodiment of the present invention relates to a dry cleaning method in which the dry cleaning apparatus shown in FIG. 1 is used, and a description will be given in reference to FIG. 1.
If the first and second solvents 4 and 4a are regarded as a low boiling point solvent and a high boiling point solvent, respectively, the latter 4a will be replaced with the former 4 in the dry cleaning apparatus during washing. The procedure of this replacement will be first described.
(1) The high boiling point solvent 4a is pumped up from the tank 3 via the valve 5a by means of the pump 6 and is delivered in a predetermined amount to the treating tank 10 through the valve 7 and the filter 8 or through the valve 9.
(2) A treating drum 11 is slowly rotated, and the high boiling point solvent 4a is circulated through a circuit consisting of the treating tank 10, the button trap 12, the valve 13, the pump 6, the valve 7, the filter 8 or the valve 9, in order to wash the clothes 2.
(3) The solvent 4a is discharged through the treating tank 10, the button trap 12, the valve 13, the pump 6, the valve 14 and the distiller 15. Afterward, the treating drum 11 is rotated at a high speed to centrifuge the high boiling point solvent 4a present in the clothes 2, and the centrifuged solvent 4a is discharged in like manner.
(4) The low boiling point solvent 4 is pumped up from the tank 3 via the valve 5a by means of the pump 6 and is delivered in a predetermined amount to the treating tank 10 through the valve 7 and the filter 8 or through the valve 9.
(5) This step is the same as in the preceding paragraph (2) (however, the high boiling point solvent 4a should be changed to the low boiling point solvent 4).
(6) This step is the same as in the preceding process (3) (however, the high boiling point solvent 4a should be changed to the low boiling point solvent 4).
(7) The treating drum 11 is slowly rotated again, and air is circulated in the direction of an arrow 20 between the treating tank 10 and the recovery air duct 19 consisting of the fan 16, the air cooler 17 and the air heater 18, whereby the clothes 2 are dried. A solvent gas vaporized from the clothes 2 is condensed in the air cooler 17 and is then delivered to the distiller 15 through the recovery circuit 21 having the non-return valve 31.
(8) When drying has been over, dampers 25, 26 are opened as depicted by dotted lines in the drawing, and fresh air is taken in through the damper 25. Further, the uncondensed solvent gas which has not been recovered by the air cooler 17 is discharged through the damper 26 in order to take away the odor of the solvent in the clothes 2.
(9) The mixed solvent (4+4a) forwarded to the distiller 15 in the preceding processes (3), (6) and (7) is first distilled at a lower boiling point of the respective solvents, and is then caused to pass through the condenser 27. The mixed solvent condensed therein is afterward introduced into the water separator 22 via the valve 32 opened under a control of a distillation temperature sensor (not shown), and is further returned to the solvent tank 3 through the solvent pipe 23.
Next, as an amount of the solvent having the lower boiling point in the distillate 15 is reduced, a temperature of the mixed solvent progressively approaches a boiling point of the other solvent 4a having a higher boiling point and the distillation of the latter 4a begins. At this time, however, the distillation temperature sensor (not shown) operates in the same manner as described above, in order to open the valve 32a (the valve 32 is shut), thereby recovering the high boiling point solvent 4a in the tank 3a in the same manner as described above (a solvent of an intermediate component in the transition from the low boiling point solvent to the high boiling point solvent is as small as trace in experiments, and thus it has no problem in practice. In consequence, the intermediate solvent may be handled as the low or the high boiling point solvent).
Next, brief reference will be made to a procedure of replacing the high boiling point solvent 4a with the low boiling point solvent 4 immediately before drying.
(1) A washing process makes progress in about the same manner as in the preceding processes (1) to (4) regarding FIG. 6 (the tank 3 and the solvent 4 in FIG. 6 should be changed to the tank 3a and the high boiling point solvent 4a).
(2) The low boiling point solvent 4 is pumped up from the tank 3 via the valve 5 by means of the pump and is delivered in a predetermined amount to the treating tank 10 through the route consisting of the valve 7 and the valve 9.
The subsequent processes are all the same as in the process (6) et seq. regarding the above-mentioned solvent replacement during washing. | The present invention relates to a dry cleaning method in which tanks for exclusively receiving at least two kinds of solvents which are soluble in each other are provided. One treating tank and a fractionating device for recovering the two or more kinds of solvents by fractonal distillation are provided. Exclusive filters for the respective solvents are provided through the use of, a common filter or a multi-filter device composed of both the filters which is disposed between the tanks and the treating tank. The two or more kinds of solvents are used independently so that washing is carried out. Further, the present disclosure relates to a dry cleaning method in which in a dry cleaner using organic solvents such as perchloroethylene, 1,1,1-trichloroethane, turpentine (oil series) and the like, the previously use solvent is replaced with another solvent which is soluble therein and has a lower boiling point, for exmple, Flon 113 or 11, during washing or immediately before drying in order to thereby shorten a drying period of time. According to this disclosure, the most proper washing method can be chosen for the greater part of materials, processings and forms of clothes, and troubles due to the wasing of the clothes can be reduced remarkably. Further, the disclosed apparatus and method can advantageously save occupation space, equipment cost, volume of facilities, maintenace cost and the like. In addition thereto, a drying time can be reduced by half. | 3 |
BACKGROUND OF THE INVENTION
This is a divisional of application Ser. No. 123,373 filed Nov. 20, 1987 now U.S. Pat. No. 4,792,413, which was a continuation of application Ser. No. 920,275 filed Oct. 17, 1986, now abandoned which was a continuation-in-part of application Ser. No. 689,336, filed Jan. 7, 1985, abandoned.
The use of Polychlorinated Biphenyls (PCBs) in industrial environments and governmental regulations for PCB use has created a need for effective PCB removal. The cleanup of PCBs has heretofore been primarily accomplished with the use of kerosene, a like-polarity solvent for PCBs. Kerosene has had widespread use but has several drawbacks including the volatile nature of the solvent, difficulty in both application and removal of the solvent from surfaces plus minimal extraction efficiency. The difficulty in the removal of the PCB-laden kerosene from surfaces is due to the lack of solvent miscibility with water in the final water rinsing. The kerosene removal problem has resulted in making PCB cleanup labor intensive.
Accordingly, a substantial need exists for PCB cleaning compositions which are easy to apply, are water miscible for rinsibility, and which have higher extraction capability for PCBs. Cleaning compositions with these attributes are more effective and will reduce the manpower needed for PCB removal. This invention provides such compositions. The compositions provided also have a low flash point and are not toxic.
Accordingly, this invention specifically relates to the removal of Polychlorinated Biphenyls (PCBs) from contaminated surfaces and to novel cleaning compositions therefor. More particularly, the invention relates to chemical compositions in which a petroleum fraction is combined with a wetting agent fraction to render the petroleum fraction water miscible. Such compositions are extremely effective for the removal of PCBs. The compositions may be applied directly in liquid form or as a foam. The foam application has advantages over previously-used PCB cleaners in that it is effective on vertical, horizontal and overhead surfaces and has superior extraction capability, and is effective in reduced application volumes. The reduction in volume of PCB-laden solvent is an important factor in PCB clean-up due to the need for its containment and subsequent disposal or destruction.
SUMMARY OF THE INVENTION
In accordance with this invention, it has been discovered that combinations of certain petroleum distillates and certain wetting agents provide compositions with the solvent extraction capability of a pure hydrophobic solvent. The petroleum distillates used can be of higher molecular weight and have a higher affinity for PCBs than the kerosene-type solvents used heretofore. The formulations allow the use of the high molecular weight solvent without sacrificing the ease of removal that is inherent with lower molecular weight petroleum fractions.
The compositions of the invention offer the miscibility of aqueous-based cleaning compositions with increased extraction efficiency for PCBs due to the petroleum fraction. The viability of these compositions is made possible by the use of a wetting agent fraction which combines the petroleum fraction and water into a stable formulation. The wetting agent fraction gives the compositions the additional capability of being applied as a foam blanket. The use of the product as a foam allows for overhead and vertical applications and provides enhanced PCB extraction. The foam also reduces the volume of material needed for PCB removal which is a means for both a reduction in labor and in disposal of waste material.
The PCB extraction compositions of the invention include: petroleum distillate and wetting agent. Additionally, the compositions may include: metal surface protectors, inorganic complexation agents, and water, for dilute application.
DESCRIPTION OF PREFERRED EMBODIMENTS
In greater detail, the compositions of the invention include essentially the following fractions or components:
1. petroleum distillates/solvents, i.e., a high boiling petroleum fraction aromatic hydrocarbon solvent having a polarity similar to PCBs and chain lengths of from about C 9 to about C 12 ; and
2. a carboxylic acid typed of wetting agent.
The compositions of the invention may be applied in a "neat" formulation or, with added water as a diluent or in a foam blanket. Water is preferably included prior to use as a diluent.
The solvent and wetting agent fractions are preferably mixed in approximately the proportions required to render them water miscible and provide solvent characteristics suitable for the amount of PCBs to be removed and for the amount involved i.e., heavy or light concentration. These proportions will depend on the specific solvent and wetting agent selected. This can be readily determined by trying a few sample mixtures on the removal site.
Generally speaking, the aromatic hydrocarbon solvent fraction will be present in approximately a weight percent range of from about 20 to about 80% (about 70% being preferred) and the wetting agent fraction will be present in approximately a weight percent range of from about 10% to about 40% (about 30% preferred). The upper limit of the amount of solvent is limited and controlled in large part by the fact that the water miscibility of the compositions tends to decrease in the higher solvent amounts. The upper limit on the wetting agent fraction is more difficult to define specifically but tends to be limited by stability considerations of the composition mixture.
The preferred aromatic hydrocarbon solvent is AMSCO Solvent G marketed by Union Oil Co. of LaMerada, Calif. This solvent consists of:
6.2% C 9 alkyl benzenes
67.5% C 10 alkyl benzenes
10.3% C 11 alkyl benzenes
0.7% C 12 alkyl benzenes
15.0% Indanes and tetralines
Balance is other aromatic hydrocarbons.
Aromatic hydrocarbon solvents other than AMSCO Solvent G may also be used if the chain length is suitable i.e., between C 9 and C 12 and the polarity is appropriate, i.e., similar to the polarity of the PCB's. For example, any of the alkyl benzenes listed above may be used individually or in sub-combinations, the C 10 length being most preferred. The substituted versions of these hydrocarbons may be used as well, such as amine, sulfonic and phosphoric substituted versions. The term "aromatic hydrocarbon solvent" is used herein to indicate all of the solvents of the type described above.
In situations involving PCB cleanup in which heavier concentrations of PCB are involved, it is preferred that up to about 15 weight % of cyclohexanol (in terms of overall composition before any water is added, i.e., "neat") or other aromatic and straight chain alcohol compounds be included as part of the solvent fraction of the composition. These are miscible with most oils and aromatic hydrocarbons.
A third type of solvent addition is also desirable in many PCB removal applications. This solvent addition is preferably ethylene glycol monobutyl ether, commercially available from Union Carbide Corp. of New York as Butyl "Cellosolve" (a trademarked product), but acetone or methylisobutyl ketone may also be used. This solvent addition may range up to about 15 weight % in terms of overall composition.
The preferred wetting agent fraction is obtained by combining a fatty acid oil having a chain length of C 10 to C 20 with ammonia, one of its derivatives: ethylamine, methylamine, ethyleneamine, diethyleneamine, dimethylamine, monoethanolamine, diethanolamine, triethanolamine or one of the substituted forms of the derivatives as follows: trihydroxyalkylamines, monohydroxyalkylamines or dihydroxyalkyl amines wherein the chain length of the alkyl group is C 2 to C 20 . Examples are monohydroxyethylamine, trihydroxyethylamine, and dihydroxyethylamine. The ammonia derivatives are preferred, monoethanolamine being the most preferred. The relative amounts of fatty acid oil or carboxylic acid to ammonia or derivative may vary over the ranges of about 30-86 weight percent for the former and about 14-70 weight percent for the latter, about 60% and 40%, respectively being preferred, particularly when AMSCO Solvent G and monoethanolamine are used. Tall oil, most preferably potassium tall oil, and animal and vegetable oils such as coconut, corn, cottonseed, lard, olive, palm, peanut, soybean, cod liver, linseed and tung oil may be used as the fatty acid oil. These oils may be readily converted more completely to include more carboxylic acid groups by treating them with potash or other caustic as is known. The active constituents of these oils are believed to be the carboxylic acids: linoleic acid, oleic acid and abietic acid. They can be synthesized and combined individually or in mixtures directly with the ammonia or ammonia derivative or substituted derivative also. As an additional wetting agent, phosphate esters may be additionally combined with the ammonia or ammonia derivative or substituted derivative. Phenol ethoxylates may be additionally included also, as can most common nonionic surfactants.
It may at times be desirable to include a sulfonic acid in the cleaning composition in order to promote stability of the overall composition. This will be especially desirable when the aromatic hydrocarbon solvent exceeds about 50% by weight of the overall composition (without water added). Although any sulfonic acid (R--SO 3 H) may be used, benzene sulfonic acid is most preferred. The amount may range up to about 20 weight % of the overall composition (without added water).
Another additional ingredient which may be included is tetrapotassium pyrophosphate or equivalent, such as ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic (HEDTA), nitrilotriacetic (NTA), or other polyphosphates, where the composition is to be used in cleanup involving inorganics, soil or hard water. The practical upper limit for this ingredient is about 5 weight % of the overall composition (without added water).
Lastly, in those instances where the cleanup involves metal surfaces, sodium metasilicate pentahydrate up to about 5 weight % of the overall composition (without added water) or other addition agents such as benzatriazole or other imidizole compounds, may also be included for passivation of the metal surfaces in similar amounts of up to about 5 weight percent.
Although the compositions described above may be prepared for shipment as described i.e., "neat" and may be used in that form, they will most likely be used in a dilute form, the diluent being water. Dilution ratios will vary over a wide range depending upon the clean-up problem to be dealt with; 1:20 is a typical dilution range.
The following Example I represents the most preferred cleaning composition. This particular composition has the advantage of being capable of being foamed by agitation and air mixing. Several types of air agitation or venturi-type systems ranging from air/chemical pressurized solution chambers to power-driven air/chemical pumps are well known and may be used for this purpose. The ability to foam is an important feature of these compositions because on application of a foam to a surface, particularly such as a ceiling or wall, the foam attaches to the surface and allows extended contact and dwell time for thorough cleanup. The particular preferred composition described below is foamed by diluting 1 part of the composition with 5 parts of water. Other ratios will be useful, again depending on the circumstances.
EXAMPLE I
______________________________________Constituent Weight %______________________________________AMSCO Solvent G 58.0Butyl "Cellosolve" (ethylene glycol 6.5monobutyl ether)Cyclohexanol 4.0Potassium Tall Oil 13.0Monoethanolamine 8.0Sulfonic Acid (neutralized with potash) 8.0Sodium Metasilicate Pentahydrate 0.5Tetrapotassium Pyrophosphate 2.5______________________________________
EXAMPLE II
A typical dilution for general foam application is represented by the following variation in Example I.
______________________________________Constituent Weight %______________________________________AMSCO Solvent G 7.5Butyl "Cellosolve" 1.0Cyclohexanol 0.5Potassium Tall Oil 1.5Monoethanolamine 1.0Sulfonic Acid (neutralized with potash) 1.0Sodium Metasilicate Pentahydrate 0.1Tetrapotassium Pyrophosphate 0.4Water (soft) 87.0______________________________________ Note: This is a typical 1:5 dilution.
Typical Cleanup Results
Using the composition of Example II in the foam form, the following results were obtained:
A. A loading dock area exhibited a reduction of PCB contamination from 7.9 ug/200 cm 2 to 4.1 ug/200 cm 2 , and
B. An injection molding area exhibited a rejection of PCB contamination from 26 ug/200 cm 2 . The supporting data for these tests are shown in Table I below.
TABLE I__________________________________________________________________________ 1248 PCB Gas Chromatographic RT of PCB 1248 - constituents Area Sample ConcentrationSample 1.50 1.86 2.25 2.60 2.76 3.19 3.70 Avg. Volumes μg/200 cm.sup.2__________________________________________________________________________109 3.708 6.035 13.050 18.444 17.447 20.499 25.032 15 FV 1.08 ml 7.9Loading 5 ul inj.DockPreclean115 3.285 4.023 7.727 9.858 9.764 11.153 13.422 8.5 FV .96 ml 4.1Loading 5 ul inj.Dock PostClean112 .346 .308 .512 .623 .490 .470 .581 .47 Dil. 1 to 100 26Injection FV 1.1 mlMolding 5 ul inj.Preclean120 4.430 6.610 10.355 13.303 8.836 13.394 12.597 9.9 FV 1.01 5.0Injection 5 ul inj.MoldingPost Clean__________________________________________________________________________
In these tests, PCB samples were taken, then the PCB-laden surfaces received a foam application of the composition at a 1:5 dilution. The foam was then given a minimum of a 5-minute dwell on the surfaces. The composition was then vacuumed up; samples were taken; the surfaces were rinsed with water and the rinse solution was removed, by vacuum. At this point, second PCB samples were taken from the surfaces to determine the extent of PCB removal.
The following experimental procedures were utilized:
1. PCB Surface Sample Collection Method
Chain of Custody forms were completed for all samples collected. The following describes the sample method used for collection of swab samples for PCB analyses.
Swab Test
a. Using template, mark corners of 20×10 cm. square in desired sample area. Number the square for future reference.
b. Put on pair of clean disposal latex gloves.
c. Fold a tissue, e.g., Kimberly Clark's "Kim Wipe" to about 1 inch×1 inch, hold in tweezers and soak with hexane.
d. Swab area four times using tweezers and tip of one finger to hold "Kim Wipe". Fold tissue over after each third time.
e. Place "Kim Wipe" in sample container (new glass container with foil in lid).
f. Rinse tweezers and finger tip with hexane into sample container.
g. Seal the sample container, complete labeling and place container in cooler.
h. Dispose of latex gloves and move to next site.
2. PCB Swab Sample Preparation Procedure
a. Remove swab from container with a hexane rinsed tweezers, and place into a 125 ml erlenmeyer flask. Rinse tweezers off into flask with hexane. Label sample for identification.
b. Rinse the sample container out three times with hexane, adding rinsings to flask. Add additional hexane to reach a final volume of approximately 75 ml into the erlenmeyer flask.
c. Homogenize sample in solvent (tissumize) swab until a pulp-like consistency is obtained.
d. Decant hexane from 125 ml erlenmeyer and pass it through a hexane rinsed column, into a Kuderna Danish receiving flask. Do not let NaSO 4 out to the air.
e. After initial decantation, swirl erlenmeyer to squeeze remaining hexane from swab, pouring hexane into column. Do this twice. Repeat tissumizing, decantation and swirling processes two more times with approximately 50 mls hexane each. Rinse probe into erlenmeyer with hexane after final tissumizing. Let solvent run through column without letting NaSO 4 out into the air. As last of solvent runs down to NaSO 4 level, rinse down sides of column with hexane. Run solvent completely out.
f. Prewet a Synder column with hexane and attach to Kuderna Danish flask that contains sample extract. Boil sample on steam bath at approximately 951/2 C. to near dryness. Take off bath, drain and cool ten minutes.
g. Place concentrator tube under nitrogen gas, blowing it down to a volume of 1 ml or slightly less.
h. Transfer sample to correct 7 ml vial after checking corresponding number of concentration tube as recorded on data sheet. Record volume on log sheet and mark it on 7 ml vial label also.
i. Do an adsorbent particle cleanup, using for example, a small particulate, e.g., "Florisil" (trademark of Floridin Co. of Pittsburgh, PA) on each sample and blank.
j. Repeat for all samples, taking care to clean Tekmar probe carefully between each sample.
3. Probe Cleaning Procedure
Fill three erlenmeyers one-third full with (1) deionized water (2) acetone, and (3) hexane, and label. Start with deionized water and blend at high speed, emptying, rinsing, refilling and repeating until no tissue pieces appear in the water. (usually 3-4 times.) Next blend with acetone. Check for tissue again. If present, empty, rinse and repeat. If not, wipe down probe with a clean tissue. Blend probe with hexane and rinse down with hexane also. If any tissue remains in probe at this point, take apart and clean by hand.
Clean the hexane rinse erlenmeyer between each sample. Rinse out thoroughly with hexane before refilling. (3) PCB analysis by EPA test method 608 for organochlorine and PCBs--July 1982.
Whereas the invention has been described in detail with reference to certain embodiments for purposes of illustration, it should be understood that variations may be made without departing from the essential features of the invention which are set forth in the following claims. | Removal and/or clean-up of polychlorinated biphenyls (PCBs) from contaminated surfaces with novel compositions of petroleum distillates and wetting agents. | 8 |
RELATED APPLICATIONS
This application is a continuation of, claims priority to, and incorporates by reference in full, the following co-pending application: U.S. patent application Ser. No. 12/497,441, filed Jul. 2, 2009, entitled “Wafer Level Optical Elements and Applications Thereof,” the entirety of which is incorporated herein by reference, now U.S. Pat. No. 8,422,138 issued Apr. 16, 2013.
FIELD OF THE INVENTION
The present invention relates to optical elements and, in particular, to optical elements having lens structures fabricated at the wafer level.
BACKGROUND OF THE INVENTION
Wafer level fabrication techniques provide for the efficient and high volume production of optical elements and other components used in optical imaging apparatus. Existing wafer level fabrication techniques for optical elements employ a transparent substrate wafer onto which optical structures, such as lenses, are formed. The transparent substrate wafer provides mechanical rigidity to the optical elements, thereby facilitating downstream handling and processing. Moreover, transparent wafer substrates provide surfaces for the installation of one or more apertures for controlling the transmission of the desired amount of electromagnetic radiation to or from other optical components or sensing components of an optical system.
FIG. 1 illustrates a wafer level optical element employing a substrate. The optical element ( 100 ) of FIG. 1 consists of a substrate ( 102 ), a first lens structure ( 104 ) deposited on a surface of the substrate ( 102 ) and a second lens structure ( 106 ) deposited on the opposing side of the substrate ( 102 ). An aperture ( 108 ) for the optical element ( 100 ) is additionally formed on a surface of the substrate ( 102 ).
The use of transparent substrate wafers, however, does present several disadvantages. One disadvantage is a reduction in modulation transfer function (MTF) values when a transparent substrate is disposed between lens structures. Moreover, substrate wafers can place design and/or mechanical restraints on optical structures deposited on the wafers. Substrate wafers, for example, can restrain the minimum center thickness of the optical element. Also, substrate wafers may behave differently over temperature fluctuations than the lens structures. Furthermore, substrate wafers contribute a significant amount to the cost of producing optical elements.
SUMMARY
In one aspect, the present invention provides wafer level optical elements that obviate a supporting substrate such as substrate wafer or a portion thereof disposed between optical structures or optical surfaces of the element. Moreover, in another aspect, the present invention provides a wafer level optical element comprising one or more apertures within the optical element, wherein the optical element does not comprise a wafer substrate or a portion thereof disposed between optical structures or optical surfaces of the element.
A wafer level optical element without a supporting substrate between optical structures or surfaces of the element can offer several advantages, including enhancing the optical performance of the element. Wafer level optical elements without a substrate between optical structures or surfaces, for example, can demonstrate reduced center thicknesses and improved MTF values. Moreover, substrate warping as a result of depositing optical structures or surfaces on the substrate is precluded with the elimination of the substrate from the construction of the optical element.
In one embodiment, an optical element of the present invention comprises a wafer level lens comprising a first lens structure coupled to a second lens structure, wherein an interface is present between the first lens structure and the second lens structure. Moreover, in coupling first and second lens structures, a wafer level lens of the present invention does not comprise a supporting substrate wafer positioned between the first lens structure and the second lens structure. In some embodiments, the interface present between the first lens structure and the second lens structure comprises an optically active surface.
The first and second lens structures of wafer level lenses can comprise any material not inconsistent with the objectives of the present invention. In some embodiments, the first and second lens structures comprise polymeric materials, glass materials or combinations thereof. Moreover, in some embodiments, the first and second lens structures comprise the same material. In other embodiments, the first and second lens structure comprise different materials.
In another embodiment, an optical element comprising a wafer level lens comprising a first lens structure coupled to a second lens structure further comprises at least one aperture disposed between the first lens structure and the second lens structure. In being disposed between the first and second lens structures, the at least one aperture, in some embodiments, is embedded in the wafer level lens.
Moreover, as a wafer level lens does not comprise a wafer substrate according to embodiments of the present invention, the at least one aperture within the lens is not associated with a wafer substrate. In some embodiments, one or more apertures of a wafer level lens are associated with the first lens structure. In other embodiments, one or more apertures of a wafer level lens are associated with the second lens structure. In another embodiment, one or more apertures are associated with both the first lens structure and the second lens structure.
An aperture, in some embodiments, can be positioned at any desired location in the wafer level lens. In some embodiments, an aperture is placed at an interface between the first lens structure and the second lens structure.
Additionally, in some embodiments, an optical element comprising a wafer level lens further comprises one or more baffles operable to reduce amounts of stray light entering the wafer level lens. In some embodiments, an optical element comprising a wafer level lens further comprises at least one spacer coupled to the wafer level lens. A spacer, in some embodiments, can provide the optical element increased rigidity, thereby facilitating downstream handling and processing. In some embodiments, for example, a spacer can facilitate stacking or coupling of the optical element comprising the wafer level lens with other optical components or sensing components.
In some embodiments, individual components of an optical element, including the first and second lens structures have the same or substantially the same coefficient of thermal expansion (CTE). In addition, one or more of the aperture, baffles and a spacer may have the same or substantially the same coefficient of thermal expansion (CTE) as the first or second lens structures. Glass substrates commonly used for support in the constructions of wafer level optical elements may have a CTE of about 1-6 ppm/degree C. In contrast polymeric materials used to foam lens structures on the supporting glass substrates may have a CTE greater than 10 ppm/degree C. and often between 18-100 ppm/degree C.
In another aspect, the present invention includes methods of producing a plurality optical elements by wafer level techniques. In one embodiment, a method of producing a plurality of optical elements comprises providing a first wafer comprising a plurality of first lens structures, providing a second wafer comprising a plurality of second lens structures and coupling the first wafer and the second wafer, wherein an interface is formed between the first lens structures and the second lens structures.
When coupled, the plurality of first lens structures achieve the desired alignment with the plurality of second lens structures to provide a plurality of joined optical elements comprising wafer level lenses. In coupling the first lens wafer and the second lens wafer, methods of the present invention do not utilize a substrate wafer disposed between lens structures of the first wafer and the second wafer.
In some embodiments, a method of producing a plurality of optical elements further comprises disposing a plurality apertures between the first wafer and the second wafer. Moreover, in some embodiments, a method of producing a plurality of optical elements further comprises singulating the plurality of joined optical elements to provide a plurality of individual optical elements.
These and other embodiments are described in greater detail in the detailed description which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a prior optical element comprising a wafer substrate between lens structures of the element.
FIG. 2 illustrates an optical element according to one embodiment of the present invention.
FIG. 3 illustrates an interface present between the first lens structure and the second lens structure of an optical element according to one embodiment of the present invention.
FIG. 4 illustrates an optical element according to one embodiment of the present invention.
FIG. 5 illustrates an optical element according to one embodiment of the present invention.
FIG. 6 illustrates a first wafer comprising a plurality of first lens structures according to one embodiment of the present invention.
FIG. 7 illustrates a first wafer comprising a plurality of first lens structures, the wafer coupled to a perforated wafer according to one embodiment of the present invention.
FIG. 8 illustrates a first wafer comprising a plurality of first lens structures, the wafer coupled to a perforated wafer according to one embodiment of the present invention.
FIG. 9 illustrates a first wafer comprising a plurality of first lens structures, the wafer further comprising a plurality of optical apertures according to one embodiment of the present invention.
FIG. 10 illustrates a second wafer comprising a plurality of second lens structures coupled to a first wafer comprising a plurality of first lens structures to provide a plurality of joined optical elements according to one embodiment of the present invention.
FIG. 11 illustrates a baffle wafer coupled to a plurality of joined optical elements according to one embodiment of the present invention.
FIG. 12 illustrates a plurality of singulated optical elements according to one embodiment of the present invention.
FIG. 13 illustrates an optical element according to one embodiment of the present invention.
DETAILED DESCRIPTION
The present invention can be understood more readily by reference to the following detailed description, examples and drawings and their previous and following descriptions. Elements, apparatus and methods of the present invention, however, are not limited to the specific embodiments presented in the detailed description, examples and drawings. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations will be readily apparent to those of skill in the art without departing from the spirit and scope of the invention.
In one aspect, the present invention provides wafer level optical elements which do not incorporate a substrate wafer between optical structures or optical surfaces of the element. In another aspect, the present invention provides a wafer level optical element comprising one or more apertures within the optical element, wherein the optical element does not comprise a supporting substrate disposed between optical structures or optical surfaces of the element. In another aspect, the present invention provides a wafer level optical element that incorporates a non-supporting substrate between optical structures or optical surfaces of the element. In some embodiments, a non-supporting substrate is substantially CTE matched to optical structures or optical surfaces of the element.
In one embodiment, an optical element of the present invention comprises a wafer level lens comprising a first lens structure coupled to a second lens structure, wherein an interface is present between the first lens structure and the second lens structure. Moreover, in coupling the first lens structure and the second lens structure, a wafer level lens of the present invention does not comprise a substrate wafer or a portion thereof between the first lens structure and the second lens structure. In some embodiments, the interface present between the first lens structure and the second lens structure comprises an optically active surface. As used herein, a surface is optically active if the surface represents an interface between two media, such as between air and polymer, that is used to reflect, refract or diffract light.
Referring now to the figures, FIG. 2 illustrates an optical element according to one embodiment of the present invention. As illustrated in FIG. 2 , the optical element ( 200 ) comprises a wafer level lens ( 202 ) comprising a first lens structure ( 204 ) coupled to a second lens structure ( 206 ). As the first lens structure ( 204 ) and the second lens structure ( 206 ) are coupled to one another, an interface ( 208 ) can exist between the first lens structure ( 204 ) and the second lens structure ( 206 ). Additionally, in contrast to the optical element illustrated in FIG. 1 , the optical element ( 200 ) of FIG. 2 does not comprise a supporting substrate wafer or a portion thereof between the first lens structure ( 204 ) and the second lens structure ( 206 ).
In some embodiments, an interface between the first lens structure and the second lens structure of an optical element of the present invention is formed by surfaces of the first and second lens structures. In other embodiments, a non-supporting material or substrate can be disposed between the first and second lens structures, wherein the non-supporting material provides an interface between the first and second lens structures. In some embodiments, a non-supporting material or substrate has a Young's modulus (E) of less than about 10 GPa. In another embodiment, a non-supporting material or substrate has a modulus (E) of less than about 5 GPa. In some embodiments, a non-supporting material or substrate has a modulus (E) of less than about 2 GPa.
The optical element ( 200 ) further comprises baffle structures ( 210 ) operable to reduce amounts of stray light entering the wafer level lens ( 202 ). Moreover, the optical element ( 200 ) further comprises a spacer ( 212 ). As provided herein, a spacer ( 212 ), in some embodiments, facilitates stacking or coupling of the optical element ( 200 ) with other optical components or electromagnetic radiation sensing components of an optical system. A spacer ( 212 ), in some embodiments, provides mechanical support to the optical element ( 200 ) including the wafer level lens ( 202 ).
FIG. 3 illustrates an interface present between the first lens structure and the second lens structure of an optical element according to one embodiment of the present invention. As illustrated in FIG. 3 , the first lens structure ( 304 ) is coupled to the second lens structure ( 306 ) such than an interface ( 308 ) is formed by surfaces of the first lens structure ( 304 ) and the second lens structure ( 306 ). In the embodiment illustrated in FIG. 3 , the interface ( 308 ) is planar. In other embodiments, however, the interface can have any desired shape including curved shapes, stepped shapes, prismatic shapes or combinations thereof. In some embodiments, the interface comprises an optically active surface.
FIG. 4 illustrates an optical element wherein the interface between the first lens structure and the second lens structure is not planar according to one embodiment of the present invention. The optical element ( 400 ) of FIG. 4 comprises a wafer level lens ( 402 ) comprising a first lens structure ( 404 ) coupled to a second lens structure ( 406 ). Coupling of the first lens structure ( 404 ) to the second lens structure ( 406 ) creates an interface ( 408 ) between surfaces of the first lens structure ( 404 ) and the second lens structure ( 406 ). The interface ( 408 ) illustrated in the embodiment of FIG. 4 is curved. In being curved, the interface ( 408 ) in FIG. 4 comprises an optically active surface if the materials used to form the first lens structure ( 404 ) and the second lens structure ( 406 ) are optically different.
In another embodiment, an optical element comprising a first lens structure coupled to a second lens structure further comprises at least one aperture disposed between the first lens structure and the second lens structure. In being disposed between the first lens structure and the second lens structure, the at least one aperture, in some embodiments, is embedded in the wafer level lens.
Additionally, as a wafer level lens does not comprise a supporting wafer substrate, according to embodiments of the present invention, the at least one aperture within the lens is not associated with a wafer substrate. In some embodiments, one or more apertures within a wafer level lens are associated with the first lens structure. In other embodiments, one or more apertures in a wafer level lens are associated with the second lens structure. In some embodiments, one or more apertures in a wafer level lens are associated with the first lens structure and the second lens structure.
An aperture in some embodiments, can be positioned at any desired location in the wafer level lens. In some embodiments, for example, an aperture is placed at an interface between the first lens structure and the second lens structure.
Referring once again to the figures, FIG. 5 illustrates an optical element according to one embodiment of the present invention. The optical element ( 500 ) illustrated in FIG. 5 comprises a wafer level lens ( 502 ) comprising a first lens structure ( 504 ) coupled to a second lens structure ( 506 ). An aperture ( 508 ) is positioned within the wafer level lens ( 502 ) at the interface ( 510 ) of the first lens structure ( 504 ) and the second lens structure ( 506 ). The aperture ( 508 ) is embedded in the wafer level lens ( 502 ). Moreover, in being positioned at the interface of the first lens structure ( 504 ) and the second lens structure ( 506 ), the aperture ( 508 ) is not associated with a supporting substrate wafer as provided in FIG. 1 .
Furthermore, since the first lens structure ( 504 ) and second lens structure ( 506 ) may be formed independent of each other, the relative position of the interface ( 510 ) and aperture ( 508 ) can be controlled. That is, the aperture ( 508 ) may be positioned closer to the first optically active surface ( 518 ) of the first lens structure ( 504 ) or to the second optically active surface ( 520 ) of the second lens structure ( 506 ). In the embodiment shown in FIG. 5 , the aperture ( 508 ) is positioned a distance T 1 from the first optically active surface ( 518 ) and a distance T 2 from the second optically active surface ( 520 ). Depending on the desired optical performance, embodiments of the optical element ( 500 ) may be characterized by T 1 being equal to T 2 , greater than T 2 , or less than T 2 .
The optical element ( 500 ) of FIG. 5 further comprises baffle structures ( 514 ) operable to reduce amounts of stray light entering the wafer level lens ( 502 ). The optical element ( 500 ) also comprises a spacer ( 516 ). As provided herein, a spacer ( 516 ), in some embodiments, facilitates stacking or coupling of the optical element ( 500 ) with other optical components or electromagnetic radiation sensing components. A spacer ( 516 ), in some embodiments, provides mechanical support to the optical element ( 500 ) including the wafer level lens ( 502 ).
FIG. 13 illustrates an optical element according to one embodiment of the present invention. The optical element ( 13 ) illustrated in FIG. 13 comprises a wafer level lens ( 14 ) comprising a first lens structure ( 16 ) and a second lens structure ( 18 ). A non-supporting material ( 20 ) is disposed between the first lens structure ( 16 ) and the second lens structure ( 18 ). The optical element ( 13 ) comprises a plurality of apertures ( 22 , 24 ) disposed between the first lens structure ( 16 ) and the second lens structure ( 18 ). Aperture ( 22 ) is positioned or embedded within the wafer level lens ( 14 ) at the interface ( 29 ) of the first lens structure ( 16 ) and non-supporting material ( 20 ). Moreover, aperture ( 24 ) is positioned or embedded in the wafer level lens ( 14 ) at the interface ( 28 ) of the second lens structure ( 18 ) and the non-supporting material ( 20 ). In the embodiment illustrated in FIG. 13 , apertures ( 22 , 24 ) have different dimensions.
The optical element ( 13 ) further comprises baffle structures ( 30 ) operable to reduce amount of stray light entering the wafer level lens ( 14 ). The optical element ( 13 ) also comprises a spacer ( 32 ). As provided herein, a spacer ( 32 ), in some embodiments, facilitates stacking or coupling the optical element ( 13 ) with other optical components or electromagnetic radiation sensing elements. A spacer ( 32 ), in some embodiments, provided mechanical support to the optical element ( 13 ) including the wafer level lens ( 14 ).
Turning now to components of optical elements of the present invention, optical elements of the present invention comprise a wafer level lens comprising a first lens structure coupled to a second lens structure.
The first lens structure comprises an optical surface of any desired profile. In some embodiments, the first lens structure comprises an optical surface having a convex profile. In other embodiments, the first lens structure comprises an optical surface having a concave profile. In another embodiment, the first lens structure comprises an optical surface having a planar profile. The first lens structure, in some embodiments, comprises an optical surface comprising a plurality of shapes, including, for example, spherical, aspherical or partially concave and/or partially convex.
Moreover, the second lens structure comprises an optical surface of any desired profile. In some embodiments, the second lens structure comprises an optical surface having a convex profile. In other embodiments, the second lens structure comprises an optical surface having a concave profile or a planar profile. The second lens structure, in some embodiments, comprises an optical surface comprising a plurality of shapes, including, for example, spherical, aspherical or partially concave and/or partially convex.
Together, the first and second lens structures may form a wafer level lens having any of a variety of shapes, including, for example, meniscus, biconvex or biconcave shapes and thereby create a lens with positive power, negative power or a combination thereof.
The first and second lens structures can comprise any material not inconsistent with the objectives of the present invention. In some embodiments, the first and second lens structures comprise polymeric materials. Polymeric materials suitable for forming lens structures of the present invention, in some embodiments, comprise epoxides, oxetanes or acrylates such as polyacrylic acid, polymethacrylic acid, polymethylmethacrlyate or combinations thereof. In some embodiments, suitable polymeric materials for lens structures comprise maleate esters, thiol-ene polymers, or vinylethers. Suitable lens structure polymeric materials, in another embodiment, comprise perfluorocyclobutane (PFBC) containing polymers, such as perfluorocyclobutane poly(arylether)s. In some embodiments, suitable polymeric materials for lens structures can comprise copolymers of two or more of the foregoing polymeric species.
In some embodiments, the first and second lens structures comprise glass materials. A suitable glass material may comprise spin-on glass or molded glass, for example.
The first and second lens structures, in some embodiments, comprise the same material. In one embodiment, for example, the first and second lens structures comprise the same polymeric material. In other embodiments, the first and second lens structures comprise different materials. In one embodiment, for example, the first lens structure comprises a polymeric material different from the second lens structure. In another embodiment, the first lens structure comprises a polymeric material and the second lens structure comprises a glass material. In some embodiments, the first lens structure comprises a glass material and the second lens structure comprises a polymeric material.
The first lens structure and the second lens structure can have any desired thicknesses not inconsistent with the objectives of the present invention. In one embodiment, the first and second lens structures have a thickness ranging from about 50 μm to about 2000 μm. In some embodiments, reduced thicknesses may be available for very small camera or other non-imaging solutions. Additionally, in some embodiments, increased thicknesses of the first and/or second lens structures may be appropriate for larger cameras or other non-imaging solutions.
As provided herein, in some embodiments, an optical element of the present invention further comprises at least one aperture disposed between the first lens structure and the second lens structure. The at least one aperture can be delineated by any material operable to block or reduce the transmission of electromagnetic radiation of the desired wavelength or range of wavelengths. In some embodiments, the at least one aperture is delineated by a material operable to block or reduce the transmission of ultraviolet radiation, visible radiation or infrared radiation or combinations thereof. In some embodiments, a material delineating the at least one aperture reflects electromagnetic radiation. In other embodiments, a material delineating the at least one aperture absorbs electromagnetic radiation.
In some embodiments, a material delineating the at least one aperture comprises a metal. Metals can comprise elementally pure metals or alloys thereof. In some embodiments, metals comprise transition metals, aluminum or combinations thereof. A metal, in some embodiments, comprises a metal film.
In other embodiments, a material delineating the at least one aperture comprises one or more polymeric materials, such as a photolithographic resist resin. In some embodiments, a photolithographic resist comprises a positive resist or a negative resist. A photolithographic resist, in some embodiments, comprises a chemically amplified resist. In another embodiment, a material delineating the least one aperture comprises a combination of one or more polymeric materials and one or more metals.
A material delineating the at least one aperture has a thickness sufficient to block the transmission of radiation of the desired wavelength or range of wavelengths. In some embodiments, the material has a thickness ranging from about 10 nm to about 0.5 mm. In another embodiment, the material has a thickness ranging from about 250 μm to about 750 μm. The material, in some embodiments, has a thickness ranging from about 300 μm to about 500 μm.
In being disposed between the first lens structure and the second lens structure, the at least one aperture, in some embodiments, is embedded in the wafer level lens and is operable to control the amount of light passing through the wafer level lens. The at least one aperture can be tailored to provide have any desired dimension. The size of the aperture can vary depending on a number of factors, including, for example, the size of the lenses fondled, the desired optical performance, desired F/14, or size of the application. As an example, an aperture for use with a lens that images onto a VGA sensor having 2.2 μm pixels may have a diameter of around 0.5 to 1.0 mm.
In some embodiments, an optical element of the present invention comprises at least one spacer. The at least one spacer, in some embodiments, is coupled to the wafer level lens. A spacer, in some embodiments, can provide the optical element increased rigidity, thereby facilitating downstream handling and processing of the optical element. In some embodiments, for example, a spacer can facilitate stacking or coupling of the optical element comprising the wafer level lens with other optical components or an electromagnetic radiation sensing component.
In one embodiment, a spacer of an optical element is constructed of polymeric materials, including, for example, polyimides or liquid crystal polymers characterized by a coefficient of thermal expansion (CTE) greater than about 11-12 ppm/degree C. In one embodiment, the spacer comprises a glass fiber reinforced polymeric resin. In some embodiments, a glass fiber reinforced polymeric resin comprises FR-4. Certain formations of FR-4 are provided with different CTE in different directions. For example, in one embodiment, the spacer material is characterized by relatively large coefficient of thermal expansion in a first direction and a substantially smaller coefficient of thermal expansion in a second substantially orthogonal direction. This difference in CTE may be as large as an order of magnitude (e.g., about 175 ppm/degree C. versus about 14 ppm/degree C. in orthogonal directions). In such cases, the spacer material may be oriented so that the least amount of thermal expansion occurs in a direction substantially parallel to the wafer level lens of the optical element. A correspondingly larger thermal expansion will thus occur along the optical axis of the element. This particular configuration may help minimize stress at the adhesive junctions over temperature changes.
An optical element comprising a wafer level lens, in some embodiments, further comprises one or more baffle structures operable to reduce the amount of stray light entering the wafer level lens. In some embodiments, baffle structures are coupled to the wafer level lens. Baffle structures can have any desired dimensions not inconsistent with the objectives of the present invention.
Baffle structures can comprise any material operable to block or reduce the transmission of electromagnetic radiation of any desired wavelength or range of wavelengths. In some embodiments, baffle structures comprise a material operable to block or reduce the transmission of ultraviolet radiation, visible radiation or infrared radiation or combinations thereof. In some embodiments, baffle structures comprise a polymeric material. In other embodiments, baffle structures comprise a metal or alloy.
In some embodiments, individual components of an optical element of the present invention, including the first and second lens structures, aperture(s), baffles and a spacer have the same or substantially the same coefficient of thermal expansion (CTE). In other embodiments, any combination of individual components of an optical element have the same or substantially the same coefficient of thermal expansion.
An optical element of the present invention comprising a wafer level lens structure, in some embodiments, can be used in camera module applications including, but not limited to, camera modules for cellular phones. In some embodiments, optical elements of the present invention can be used in various surveillance applications and equipment requiring miniaturization of optical components such as mobile computing devices, automobiles, security, consumer electronics, toys and the like.
In another aspect, the present invention provides methods of producing a plurality of optical elements comprising a wafer level lens comprising a first lens structure coupled to a second lens structure. As an optical element of the present invention does not comprise a supporting substrate between the first and second lens structures, methods of the present invention, in some embodiments, do not use substrate wafers.
In one embodiment, a method of producing a plurality of optical elements comprises providing a first wafer comprising a plurality of first lens structures, providing a second wafer comprising a plurality of second lens structures and coupling the first wafer to the second wafer, wherein an interface is formed between the first lens structures and the second lens structures. When coupled, the plurality of first lens structures and the plurality of second lens structures achieve the desired alignment resulting in the production of a plurality of joined optical elements comprising wafer level lenses.
In some embodiments, providing a first wafer comprising a plurality of first lens structures comprises providing a first lens material and forming the first lens material into the first wafer comprising the plurality of first lens structures. Moreover, in some embodiments, providing a second wafer comprising a plurality of second lens structures comprises providing a second lens material and forming the second lens material into the second wafer comprising the plurality of second lens structures. In some embodiments, forming the first lens material into the first wafer comprising the plurality of first lens structures comprises molding the first lens material into the plurality of first lens structures. In some embodiments, forming the second lens material into the second wafer comprising the plurality of second lens structures comprises molding the second lens material into the plurality of second lens structures.
In providing a first wafer, in some embodiments, the plurality of first lens structures are formed simultaneously or substantially simultaneously. In other embodiments, the plurality of first lens structures are formed serially or sequentially. In providing a second wafer, in some embodiments, the plurality of second lens structures are formed simultaneously or substantially simultaneously. In other embodiments, the plurality of second lens structures are formed serially or sequentially.
In some embodiments wherein the first and/or second lens materials are molded, molds suitable for molding the first and second lens materials into first and second wafers comprising lens structures can have any desired shape and/or dimensions. In some embodiments, a mold for producing a first wafer comprising a plurality of first lens structures has a shape and/or dimensions different from a mold for producing a second wafer comprising a plurality of second lens structures. The shape and/or dimensions of a mold are generally governed by the desired shape and/or dimensions of the lens structures of a wafer.
As provided herein, the first and second lens materials can comprise any materials not inconsistent with the objectives of the present invention. In some embodiments, the first and second lens materials can comprise any of the polymeric materials or glass materials described herein. Moreover, in some embodiments, the first lens material and the second lens material are the same. In other embodiments, the first lens material and the second lens material are different.
The first wafer comprising a plurality of first lens structures and the second wafer comprising a plurality of second lens structures can be coupled by a variety of methods. In one embodiment, the first wafer and the second wafer are coupled by forming the second wafer on a surface of the first wafer. In another embodiment, the first wafer and the second wafer are coupled by forming the first wafer on a surface of the second wafer.
In some embodiments, the first wafer and the second wafer are coupled by molding the second wafer on a surface of the first wafer. In another embodiment, the first wafer and the second wafer are coupled by molding the first wafer on a surface of the second wafer.
Additionally, in some embodiments, the first wafer and the second wafer are coupled by an adhesive or other non-rigid, non-crystalline or non-supporting material.
In some embodiments, a method of producing an optical element further comprises disposing a plurality of apertures between the first wafer comprising a plurality of first lens structures and the second wafer comprising a plurality of second lens structures.
Disposing a plurality of apertures between the first wafer and the second wafer, in some embodiments, comprises patterning a surface of the first wafer with a material such as a resist. In some embodiments, patterning comprises selectively depositing a material on a surface of the first wafer. In other embodiments, patterning comprises depositing a material on a surface of the first wafer and selectively etching areas of the deposited aperture material to provide apertures in the material. Etching in some embodiments, comprises chemical etching, radiative etching or combinations thereof.
Disposing a plurality of apertures between the first wafer and the second wafer, in some embodiments, comprises patterning a surface of the second wafer with a material such as a resist. In some embodiments, patterning comprises selectively depositing a material on a surface of the second wafer. In other embodiments, patterning comprises depositing a material on a surface of the second wafer and selectively etching areas of the deposited aperture material to provide apertures in the material. Etching in some embodiments, comprises chemical etching, radiative etching or combinations thereof.
Moreover, in some embodiments, disposing a plurality of apertures between the first wafer and the second wafer comprises patterning a surface of the first wafer and patterning a surface of the second wafer with one or more aperture materials.
In some embodiments, a surface of the first wafer and/or the second wafer is patterned with an aperture material prior to coupling of the wafers. In other embodiments, a surface of the first and/or second wafer is patterned with an aperture material after coupling of the wafers.
In some embodiments, methods of producing a plurality of optical elements further comprises coupling a perforated wafer to the joined optical elements. A perforated wafer, in some embodiments, is coupled to the first wafer comprising the plurality of first lens structures. In other embodiments, a perforated wafer is coupled to the second wafer comprising the plurality of second lens structures. In another embodiment, a first perforated wafer is coupled to the first wafer and a second perforated wafer is coupled to the second wafer.
A perforated wafer can be coupled to the first or second wafer by any method known to one of skill in the art. In one embodiment, for example, a perforated wafer is coupled to the first or second wafer by an adhesive, such as an adhesive curable by exposure to ultraviolet light or heat, for example.
In some embodiments, a perforated wafer is a spacer wafer. In other embodiments, a perforated wafer is a baffle wafer.
As provided herein, coupling of the first wafer comprising a plurality of first lens structures with the second wafer comprising a plurality of second lens structures provides a plurality of joined optical elements comprising wafer level lenses. Methods of the present invention, in some embodiments, further comprise singulating the plurality of joined optical elements to provide a plurality of individual optical elements. Singulation of the joined optical elements can be achieved by dicing blades, lasers or any other suitable technique known to one of skill in the art.
Referring once again to the figures, FIGS. 6 through 12 demonstrate production of an optical element according to one non-limiting embodiment of the present invention.
FIG. 6 illustrates a first wafer comprising a plurality first lens structures according to one embodiment of the present invention. As illustrated in FIG. 6 , the first wafer ( 600 ) comprises a plurality of molded first lens structures ( 602 ). In being molded, the first wafer ( 600 ) and the plurality of first lens structures ( 602 ) comprise a first polymeric material. The first wafer ( 600 ) comprises a surface ( 604 ) coupled to a rigid carrier substrate ( 606 ) for mechanical support to facilitate downstream processing into an optical element of the present invention. A release layer ( 608 ) is disposed between surface ( 604 ) of the first wafer ( 600 ) and the carrier ( 606 ) to permit removal of the first wafer ( 600 ) from the substrate ( 606 ) when desired. In one embodiment, the carrier ( 606 ) is transparent to permit exposure by UV light through the carrier ( 606 ) to cure the first wafer ( 600 ).
A perforated wafer ( 700 ) is subsequently coupled to the first wafer ( 600 ) comprising the plurality of first lens structures ( 602 ) by an adhesive ( 702 ) as illustrated in the embodiment of FIG. 7 . The adhesive ( 702 ) used to couple the perforated wafer ( 700 ) to the first wafer ( 600 ), in some embodiments, can be a radiation curable or a heat curable adhesive. In one embodiment, the transparent nature of the carrier ( 606 ) and the first wafer ( 600 ) permits curing of the adhesive ( 702 ) by providing radiation of the proper wavelength through the substrate ( 606 ) and the first wafer ( 600 ). In another embodiment, the adhesive ( 702 ) is cured via another catalyst (e.g., heat, time, or anaerobic). Consequently, the carrier ( 606 ) may be constructed of a non-transparent material.
As provided herein, the perforated wafer, in some embodiments, can be a spacer wafer and can provide mechanical support to an optical element and/or components thereof to facilitate downstream handling and processing. Therefore, once the perforated wafer ( 700 ) is coupled to the first wafer ( 600 ) comprising the plurality of first lens structures ( 602 ), the first wafer ( 600 ) can be removed from the carrier as illustrated in the embodiment of FIG. 8 .
According to FIG. 9 , a plurality of apertures ( 900 ) are subsequently patterned on the surface ( 604 ) of the first wafer ( 600 ) previously coupled to the carrier ( 606 ). The plurality of apertures ( 900 ) are delineated by a material ( 902 ) operable to block the transmission of radiation of the desired wavelength. The apertures ( 900 ) are operable to adjust the amount of light passing through the wafer level lens of an optical element of the present invention.
FIG. 10 illustrates a second wafer comprising a plurality of second lens structures coupled to the first wafer ( 600 ) comprising the plurality of first lens structures ( 602 ) according to one embodiment of the present invention. As illustrated in FIG. 10 , a second wafer ( 10 ) comprising a plurality of second lens structures ( 12 ) is coupled to a surface of the first wafer ( 600 ). As provided herein, the second wafer ( 10 ) can be formed onto a surface of the first wafer ( 600 ). Alternatively, the second wafer ( 10 ) can be coupled to the first wafer ( 600 ) by a non-supporting material such as an adhesive. In some embodiments, an interface ( 16 ) is formed between the first lens structures ( 602 ) and the second lens structures ( 12 ).
As illustrated in FIG. 10 , coupling second wafer ( 10 ) comprising the plurality of second lens structures ( 12 ) to a surface ( 604 ) of the first wafer ( 600 ), provides a plurality of joined optical elements ( 18 ) having an aperture ( 904 ) embedded therein, the apertures delineated by material ( 902 ).
As described herein, in some embodiments, a second perforated wafer is coupled to the joined optical elements. In some embodiments, the second perforated wafer is a baffle wafer. In the embodiment illustrated in FIG. 11 , a baffle wafer ( 24 ) is coupled to a surface ( 26 ) of the second wafer ( 10 ). The baffle wafer ( 24 ) can be coupled to the second wafer ( 10 ) by an adhesive ( 28 ), such as a radiation or heat curable adhesive. The baffle wafer ( 24 ) provides baffle structures to each of the optical elements ( 18 ) operable to reduce amounts of stray light entering the wafer level lens of each element formed by the first lens structure ( 602 ) and the second lens structure ( 12 ).
Moreover, the plurality of joined optical elements can be singulated to provide a plurality of independent optical elements ( 30 ) as illustrated in FIG. 12 .
Embodiments of the present invention a further illustrated in the following non-limiting examples.
Example 1
Plurality of Optical Elements
A plurality of optical elements of the present invention were fabricated according to the following procedure.
A temporary coating of polydimethylsiloxane (PDMS) was spun on temporary carrier wafer of fused silica glass at 2700 rpm followed by cure at 150° C. for 30 minutes. Optical polymer was replicated on the temporary PDMS coating to form a first wafer comprising a plurality of first lens structures. The polymer was UV-cured at 20 mW/cm 2 for 50 sec. A perforated substrate was subsequently bonded to the first wafer with thermal epoxy (353ND) at 90° C. for 1 h. Afterwards, the temporary carrier wafer was separated from the first wafer.
The perforated substrate having the first lens surface above each hole was baked at 150° C. for 3 h. A layer of Cr metal having a thickness of about 500 μm was deposited on the backside of the first wafer comprising the plurality of first lens structures using thermal evaporation equipment. Positive resist was spun on top of the deposited Cr metal at 3000 rpm followed by soft cure at 110° for 30 min. in convection oven. The photoresist was exposed to radiation through a mask having an aperture pattern with energy of about 100 mJ/cm 2 . The wafer was developed in TMAH-like solution for 30 sec followed by metal etching to form the aperture openings in the resist. The remaining portion of the resist underwent blanket exposure to radiation at about 300 mJ/cm 2 followed by removal in the TMAH-like solution.
A second lens wafer comprising a plurality of second lens structures was replicated on the backside of the first wafer in such a way that both the first and second lens structures and the metal apertures were aligned accordingly to provide a plurality of joined optical elements. The second lens structures comprised the same optical polymer as the first lens structures. An interface was present between the first and second lens structures. The plurality of joined optical elements were cured at 150° C. for 3 h. The plurality of joined optical elements were singulated to individual optical elements by a dicing saw using a resin blade. The optics of the individual elements were tested to get the MTF and FFL values. After assembly into the socket the pictures were taken using the prepackaged VGA sensor.
Various embodiments have of the invention have been described in fulfillment of the various objects of the present invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the invention. | A wafer level lens includes a first lens structure of a first polymeric material coupled to a second lens structure of a second polymeric material, wherein an interface is formed by opposing surfaces of the first lens structure and the second lens structure, the opposing surfaces having no air gap therebetween, at least one aperture disposed between the first lens structure and the second lens structure, wherein the aperture contacts the first lens structure and the second lens structure and wherein a supporting substrate is not positioned between the first lens structure and the second lens structure, and a spacer coupled to and separate from the wafer level lens. | 1 |
FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention relates to a continuous fabric-dyeing apparatus and a method therefor, and, more particularly, to a continuous fabric-dyeing apparatus for, and method of, dyeing bulky, three-dimensional fabrics and narrow fabrics having a plurality of hard protrusions such as a trim tape, zip tape, hook-and-loop fastener tape, and braided cords.
[0002] Various known machines for continuous dyeing of narrow fabrics rely on a dip trough and roller squeezing mechanism, commonly referred to as a padding machine, to control the amount of dye liquor deposited on the fabric (U.S. Pat. Nos. 5,050,258, 5,205,008, 4,878,365, and 3,995,457). The padding machine may include single or multiple baths (U.S. Pat. No. 4,997,453). Alternatives to squeeze rollers such as absorbent fiber webs, have been taught (U.S. Pat. No. 4,046,506). The impregnated fabric is then subjected to dry or steam heating to fix the dye in the fibers of the fabric (U.S. Pat. No. 6,364,189). Alternative heating media have been taught such as high boiling-point fluorocarbon liquids (U.S. Pat. No. 3,958,934). The fabric is then washed off to remove excess unfixed dyestuff. Various continuous dyeing methods of impregnating-dipping, squeezing and thermally fixing are also known.
[0003] When the fabric for dyeing is a three-dimensional fabric, a narrow fabric having a plurality of hard protrusions, and the like, the above-referenced machines for continuous dyeing are prone to producing an unevenly dyed product, due to uneven pressure from the squeeze rollers. Additionally, such machines may be subject to frequent deformation of the squeezing rollers, guides and feed rollers because the protrusions on the fabric continuously gouge these elements as the fabric traverses the machine.
[0004] There is therefore a recognized need for, and it would be highly advantageous to have, a continuous fabric-dyeing apparatus for, and method of, dyeing bulky, three-dimensional fabrics and narrow fabrics having a plurality of hard protrusions, that produce an evenly dyed product. It would be of further advantage if the apparatus and method would be simple, robust, and economical, with respect to the known art.
SUMMARY OF THE INVENTION
[0005] The present invention is a continuous dyeing apparatus and method therefor.
[0006] According to the teachings of the present invention there is provided a dyeing apparatus for continuous dyeing of a fabric article with dye, the apparatus including: (a) a dyeing vessel for containing therein a high-density liquid; (b) a heating mechanism, thermally associated with the dyeing vessel, for heating a dye fixation zone within the vessel to a temperature above 70° C.; (c) a continuous transport mechanism for continuously transporting the fabric article, through a dye impregnation chamber, and through the dye fixation zone of the dyeing vessel, and (d) a dye-dispensing mechanism for delivering a dye liquor within the dye impregnation chamber, so as to impregnate with the dye, the fabric article passing through the chamber, wherein the dyeing vessel is dimensioned and configured such that a height of the high-density liquid, when disposed in the vessel, delivers a hydrostatic pressure of at least 0.1 bar gauge to the dye fixation zone, so as to effect fixation of the dye in the fabric article.
[0007] According to further features in the described preferred embodiments, the dyeing vessel includes at least a first upwardly directed member and a second upwardly directed member for containing therein the high-density liquid, the first upwardly directed member for allowing the transporting of the fabric article downwards into the dye fixation zone, and the second upwardly directed member for allowing the transporting of the fabric article upwards out of the dye fixation zone.
[0008] According to still further features in the described preferred embodiments, the dyeing vessel is further configured so as to fluidly communicate with an ambient environment.
[0009] According to still further features in the described preferred embodiments, the first upwardly directed member and second upwardly directed member are associated so as to form a first U-tube.
[0010] According to still further features in the described preferred embodiments, the U-tube is further configured so as to fluidly communicate with an ambient environment.
[0011] According to still further features in the described preferred embodiments, the dyeing vessel includes the first U-tube and at least a second U-tube, the first and second U-tubes connected in series, the second U-tube having upwardly directed members.
[0012] According to still further features in the described preferred embodiments, the first and second U-tubes connected in the series are fluidly connected by an inverted U-tube disposed therebetween.
[0013] According to still further features in the described preferred embodiments, the dyeing vessel at least partially contains the dye impregnation chamber, such that the dye liquor for the dye impregnation chamber is disposed above the high-density liquid when disposed in the dyeing vessel.
[0014] According to still further features in the described preferred embodiments, the transport mechanism includes at least one guide disposed within the dyeing vessel, the guide being configured for guiding the fabric article within the dyeing vessel.
[0015] According to still further features in the described preferred embodiments, the guide is a rotating guide, the rotating guide being configured for guiding the fabric article within the dye fixation zone within the dyeing vessel.
[0016] According to still further features in the described preferred embodiments, the transport mechanism includes at least one rotating guide being configured for guiding the fabric article around a curve in a bottom section of the first U-tube.
[0017] According to still further features in the described preferred embodiments, the dye-dispensing mechanism includes a reservoir.
[0018] According to still further features in the described preferred embodiments, the dyeing apparatus further includes: (e) at least one air jet, disposed with respect to the dyeing vessel so as to deliver an air stream on the fabric article after the article has been conveyed out of the dye fixation zone by the continuous transport mechanism.
[0019] According to still further features in the described preferred embodiments, the dyeing apparatus further includes: (e) at least one brushing mechanism including a brush, disposed with respect to the dyeing vessel such that the brush impinges on the fabric article after the article has been conveyed out of the dye fixation zone by the continuous transport mechanism.
[0020] According to still further features in the described preferred embodiments, the apparatus further includes the high-density liquid.
[0021] According to still further features in the described preferred embodiments, the high-density liquid includes at least one molten metal.
[0022] According to another aspect of the present invention there is provided a continuous method of dyeing a fabric article with dye, the method including the steps of: (a) providing a dyeing apparatus including: (i) a dyeing vessel for containing therein a high-density liquid; (ii) a heating mechanism, thermally associated with the dyeing vessel, and (iii) a continuous transport mechanism for continuously transporting the fabric article, through a dye impregnation chamber, and through a dye fixation zone of the dyeing vessel; (b) impregnating the fabric article with the dye in the dye impregnation chamber; (c) maintaining, within the dye fixation zone, a hydrostatic pressure of at least 0.1 bar gauge using the high-density liquid, and a temperature of at least 70° C., using the heating mechanism, and (d) passing the fabric article through the high-density liquid and into the dye fixation zone so as to fixate the dye on the fabric article.
[0023] According to still further features in the described preferred embodiments, the high-density liquid has a specific gravity above 6.
[0024] According to still further features in the described preferred embodiments, the high-density liquid includes at least one liquid selected from the group consisting of high molecular-weight polymer liquids and salt brines.
[0025] According to still further features in the described preferred embodiments, the high-density liquid includes at least one molten metal.
[0026] According to still further features in the described preferred embodiments, the fabric article is a tape.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Throughout the drawings, like-referenced characters are used to designate like elements.
[0028] In the drawings:
[0029] FIG. 1 is a schematic cross-sectional representation of a continuous dyeing apparatus according to a first embodiment of the present invention, and
[0030] FIG. 2 is a schematic cross-sectional representation of a continuous dyeing apparatus according to a second embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] The present invention is a continuous dyeing apparatus and method therefor.
[0032] The principles and operation of the continuous dyeing apparatus and method according to the present invention may be better understood with reference to the drawings and the accompanying description.
[0033] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawing. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.
[0034] An object of the present invention is to provide a continuous dyeing apparatus for controllably dyeing articles such as bulky and uneven narrow fabric without entailing problems such as uneven dyeing of fabric and deformation of the dyeing machine squeezing rollers and guide rollers.
[0035] To accomplish this object, the present invention provides a dyeing apparatus having a dyeing vessel adapted to contain a high-density liquid heating medium therein. The dyeing apparatus has a transport mechanism and rollers for transporting the fabric article through the dyeing vessel. The penetration of the dye substance into the fabric article is effected by subjecting the article to superambient pressure and superambient temperature as the article is continuously conveyed through the dyeing vessel.
[0036] A schematic cross-sectional representation of a continuous dyeing apparatus 100 according to a first embodiment of the present invention is provided in FIG. 1 . Dyeing apparatus 100 preferably includes a dyeing vessel 1 , electrical coil heating members 2 , a dye reservoir 5 , a let-off device 6 , a tape or fabric 7 to be dyed, an air jet device 19 and/or a brushing device 9 , guide rollers 10 , a drying device 11 , a frame 12 , and a motorized transport device 14 .
[0037] As will be elaborated hereinbelow, dyeing vessel 1 includes a dye liquor impregnation zone 3 , a zone containing a high-density liquid heating medium 4 , and a wash-off zone 8 .
[0038] In the embodiment schematically provided in FIG. 1 , dyeing vessel 1 is a vertically oriented, cylindrical “U”-shaped tube. Typically, dyeing vessel 1 has a height of 150 centimeters and a diameter of 10 centimeters, and contains a dense liquid for providing heat at 135° C. The liquid may contain bismuth, tin, lead, indium or cadmium, or a combination thereof (e.g., Neylo® 158, obtained from Ney Metals®, N.Y., N.Y.). The tape to be dyed is continuously fed from a package, box or reel 22 into dye liquor impregnation zone 3 . Preferably, dye liquor impregnation zone 3 , is situated within the tube of dyeing vessel 1 , above high-density liquid heating medium 4 . Alternatively, dye liquor impregnation zone 3 may be disposed outside of the U-tube.
[0039] Fresh dye liquor stored within dye reservoir 5 is continuously or intermittently fed to the impregnation zone 3 so as to maintain a substantially constant amount of dye therein.
[0040] When motorized transport device 14 is operated, tape 7 , which is engaged by transport device 14 , is conveyed through the tube of dyeing vessel 1 . After being impregnated with dyestuff in impregnation zone 3 , tape 7 passes through high-density liquid heating medium 4 . As tape 7 proceeds downwards, the hydrostatic pressure in the tube of dyeing vessel 1 gradually increases. Electrical coil heating members 2 , disposed around the tube of dyeing vessel 1 , supply heat so as to attain the requisite temperature. Depending on the particular application, the requisite temperature is at least 60° C., and more typically 130° C., and up to at least 200° C.
[0041] Similarly, for a given high-density liquid, the height of the liquid determines the hydrostatic pressure in the tube. Thus, the height of the liquid can be adjusted to attain the requisite pressure for a given application. Preferably, the requisite pressure is above 0.1 bar, more preferably, above 1 bar, and most preferably, from 1 bar to 6 bar.
[0042] As used herein in the specification and in the claims section that follows, the term for the units of pressure, “bar” values are gauge values.
[0043] The bottom of the tube of dyeing vessel 1 is preferably curved, so as to facilitate the movement of tape 7 therethrough. The movement of tape 7 is further facilitated by tape guides disposed within the tube. In an exemplary embodiment provided in FIG. 1 , the tape guides (rotating guides or bearings 13 ) are disposed within the U-tube of dyeing vessel 1 , near the inner curve of the U-tube, such that tape 7 passes between rotating guides 13 and the outer curve of the U-tube. Rotating guides 13 serve, inter alia, to guide tape 7 while reducing frictional forces and preventing tearing of tape 7 and/or damage to the dyeing process.
[0044] After passing around rotating guides 13 , tape 7 proceeds upwards through high-density liquid heating medium 4 , and subsequently, through wash-off zone 8 . After emerging from the tube, tape 7 passes through air jet device 19 and brushing device 9 , where the cleaning operation is completed. Subsequently, tape 7 is dried as it passes through a drying device 11 , before tape 7 is collected in/on a package, box or reel 24 .
[0045] Dyeing vessel 1 is advantageously disposed in a housing 12 , which may also include drying device 11 . Although housing 12 may also contain dye reservoir 5 , it is usually preferable to situate dye reservoir 5 outside of housing 12 , so as to facilitate the introduction of additional dye material to reservoir 5 .
[0046] It will be apparent to one skilled in the art that various mechanical elements, such as a let-off element 6 , and guide rollers 10 , may be advantageously employed in conveying tape 7 through continuous dyeing apparatus 100 .
[0047] Although high-density liquid heating medium 4 preferably includes molten metals, as described hereinabove, other high-density liquids may be suitable, provided that the liquids engender and maintain the requisite pressure range (and 0.1 bar to 6 bar) and temperature range (60° C. to 200° C.) for a particular dyeing application. Thus, in another preferred embodiment of the present invention, liquid heating medium 4 includes at least one high-density salt brine (e.g., zinc bromide, calcium bromide, or potassium formate). In this case, the lower specific gravity of the salt brine, with respect to the specific gravity of a molten metal, necessitates a higher fluid level to achieve an identical pressure.
[0048] A schematic cross-sectional representation of a continuous dyeing apparatus 200 according to a second embodiment of the present invention is provided in FIG. 2 . Dyeing apparatus 200 is largely similar to dyeing apparatus 100 of FIG. 1 , but the dyeing vessel includes two vertically oriented, cylindrical, U-shaped tubes 201 , 202 and an inverted U-shaped cylindrical tube 203 connecting therebetween. Inverted U-tube 203 normally becomes at least partially filled with water vapor during the course of operation. Hence, inverted U-tube 203 is advantageously equipped with a controlled pressure release valve 15 , for stabilizing the pressure within the system.
[0049] Fabric or tape 7 to be dyed is continuously fed from a package, box or reel 22 into the dyeing vessel, and is subsequently removed from the dyeing vessel, in a substantially identical method to that described with respect to FIG. 1 .
[0050] By controlling the speed of traverse, the temperature and height of the liquid heating medium and the concentration and amount of dyestuff in the impregnation zone, consistent and even dyeing is achieved.
[0051] Owing to the construction described above, it is possible to dye the article in a continuous, controlled fashion. The apparatus is designed and operated such that an even pressure is applied to all parts of the fabric. Consequently, an even distribution of dyestuff is deposited over the entire fabric article. The pressures and temperatures in the apparatus are predetermined so as to efficiently fix the dyestuff to the article.
[0052] It must be emphasized that the present dyeing machine requires no squeeze rollers, and relies on the hydrostatic pressure and thermal energy of the high-density liquid heating medium to control the amount of the dyeing liquid for impregnating in the fabric article. Advantageously, excess dyestuff floats to the top of the high-density liquid so that little or no wash-off is required. The hot liquid also facilitates dye fixation and drying of the article after the dyestuff has penetrated the article.
[0053] In a preferred method of dyeing polyester tape to dark shades in the above-described apparatus, disperse dyes (such as Terasil®, Ciba®, Switzerland) are mixed in water containing up to 5% by weight of a dispersing agent (such as IFCOSOL-DA LIQUID®, Molchemie®, India), up to 5% by weight leveling agent (such as ESQUAL T-56 CONC®), Winimex®, Thailand) and up to 5% by weight organic acid. The resulting dye liquor is introduced into the liquor impregnation zone. The liquid heating medium is heated to 130° C., and the greige tape is traversed through the apparatus at 15 to 30 meters per minute.
[0054] As used herein in the specification and in the claims section that follows, the term “high-density liquid” refers to a liquid having a specific gravity above 2, preferably, above 4, more preferably, above 6, and most preferably, above 10.
[0055] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. For example, although the first embodiment illustrated in FIG. 1 employs a U-shaped vessel, any shape that can contain the high-density heating medium liquid, allow transport of the narrow fabrics therethrough, and engender the temperature/pressure regimen described herein, is included. Moreover, while the U-shaped vessel typically has a circular cross-section, other cross-sections such as oblong, triangular, square, rectangular, multilateral or multi-lobed, could be used in the apparatus and method of the present invention. More generally, the invention is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
[0056] All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. | A dyeing apparatus and method for continuous dyeing of a fabric article with dye, the apparatus including: (a) a dyeing vessel for containing a high-density liquid; (b) a heating mechanism, thermally associated with the dyeing vessel, for heating a dye fixation zone within the vessel to a temperature above 70° C.; (c) a continuous transport mechanism for continuously transporting the fabric article, through a dye impregnation chamber, and through the dye fixation zone of the dyeing vessel, and (d) a dye-dispensing mechanism for delivering a dye liquor within the dye impregnation chamber, so as to impregnate with the dye, the fabric article passing through the chamber, and wherein the dyeing vessel is dimensioned and configured such that a height of the high-density liquid delivers a hydrostatic pressure of at least 0.1 bar gauge to the dye fixation zone, so as to effect fixation of the dye in the fabric article. | 3 |
BACKGROUND OF THE INVENTION
This invention pertains to the use of dimercapto-substituted dinitrile compounds as antimicrobials agents.
U.S. Pat. No. 2,533,233 discloses the preparation of compounds of the formula: ##STR3## wherein R in an alkyl or aralkyl group. These compounds are disclosed as being useful as intermediates for the production of organic compounds of commercial utility. U.S. Pat. No. 3,776,891 discloses the preparation of compounds of the formula:
(CN).sub.2 C═C(S-A-NRR.sub.1).sub.2
wherein A represents a straight- or branched-chain alkylene of 2-4 carbon atoms and R and R 1 independently represent lower alkyl, aralkyl or cycloalkyl. These compounds are disclosed as being useful as accelerators for the vulcanization of rubber.
U.S. Pat. No. 4,087,451 discloses the preparation of compounds of the formula: ##STR4## wherein X represents chlorine, bromine or iodine, and R' and R" may be the same or different and are selected from the group consisting of hydrogen and acyclic hydrocarbon monovalent radicals having 1-8 carbon atoms. These compounds are disclosed as being useful as antimicrobials.
U.S. Pat. No. 4,389,400 discloses the preparation of compounds of the formula: ##STR5## wherein X represents chlorine, bromine or iodine, and R' and R" may be the same or different and are selected from the group consisting of hydrogen and acyclic hydrocarbon monovalent radicals having 1-8 carbon atoms. These compounds are disclosed as being useful as antimicrobials.
The desirability of identifying or discovering new antimicrobial agents is widely recognized. New antimicrobial agents are desired for several reasons: these include, but are not limited to, responding to the problem created by the development of microbe strains resistant to known antimicrobials, the occurrence of undesirable interactions of certain known antimicrobials with the medium or product in which the antimicrobial is used, and high toxicity of certain known antimicrobials to certain non-target organisms such as mammals.
The present invention solves these problems by disclosing new compounds which may be employed as an antimicrobial.
SUMMARY OF THE INVENTION
The present invention is a compound corresponding to the formula: ##STR6## wherein X represents: ##STR7##
The present invention is also an antimicrobial composition comprising an inert diluent and an antimicrobially-effective amount of a compound corresponding to the formula: ##STR8## wherein X represents: ##STR9##
The present invention is also a method for inhibiting microorganisms in a microbial habitat comprising contacting said microbial habitat with an antimicrobially-effective amount of a compound corresponding to the formula: ##STR10## wherein X represents:
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a compound corresponding to the formula: ##STR12## wherein X represents: ##STR13##
The bis(thiomethylthiocyanate)methylene)propanedinitrile compound of the present invention, wherein X represents: ##STR14## may be prepared by the reaction of chloromethylthiocyanate with di(sodiomercapto)methylenemalononitrile. The general reaction scheme for this reaction is as follows: ##STR15## The use of di(sodiomercapto)methylenemalononitrile to prepare other compounds is known and is generally disclosed in U.S. Pat. Nos. 4,038,393: 4,075,204 and 4,075,205.
The Z-2,3-bis(thiomethylthiocyanate)-2-butenedinitrile compounds of the present invention, wherein X represents: ##STR16## may be prepared by the reaction of chloromethyl-thiocyanate with disodium dimercaptomaleonitrile. The general reaction scheme for this reaction is as follows: ##STR17## The use of disodium dimercaptomaleonitrile to prepare other compounds is known and is generally disclosed in U.S. Pat. Nos. 3,761,475: 4,172,133: 4,199,581 and 4,210,645.
In carrying out these reactions, the chloromethylthiocyanate and the di(sodiomercapto)methylenemalononitrile and/or disodium dimercaptomaleonitrile are typically mixed together in substantially 2 to 1 molar ratio amounts. Preferably, the chloromethylthiocyanate is added dropwise to a solution of the di(sodiomercapto)-methylenemalononitrile and/or disodium dimercapto-maleonitrile.
Other alkaline or alkali earth metal salts such as, for example, the dipotassium salts, of X-2,3-dimercapto-2-butenedinitrile and (dimercaptomethylene)propanedinitrile may also be substituted for the disodium salts in the reaction mixture.
Preferably, the reactions are carried out in an inert solvent such as dimethyl formamide, methanol, acetonitrile, acetone, or pyridine. Preferably, the reactions are carried out at 0° C. under an ambient pressure of inert gas. Subsequent to the addition of the appropriate reaction materials, the reaction mixture is allowed to stir at a temperature of between about 25° C. to about 60° C. for a period of between about 2 to about 24 hours in order to increase the reaction rate and promote extinction of the limiting reagent. Final work-up of the reaction mixture then provides the desired final product.
PREPARATION OF STARTING MATERIALS
The synthesis of chloromethylthiocyanate is straight-forward and is described in the art, such as in Japanese Patents 62215561 and 62215562.
The synthesis of (sodiomercapto)methylenemalononitrile is straightforward and is described in the art, such as in A. Adams et al., J. Chem Soc., 3061 (1959)
The synthesis of disodium dimercaptomaleonitrile is straightforward and is described in the art, such as in Muetterties, Inorganic Synthesis, Volume X, p. 11.
The following examples illustrate the present invention and the manner by which it can be practiced but, as such, should not be construed as limitations upon the overall scope of the same.
EXAMPLE 1
Preparation of Bis(thiomethylthiocyanate)-methylene)propanedinitrile
To a solution of (dimercaptomethylene)propanedinitrile-disodium salt (4.33 grams, 0.023 mol) in dimethyl formamide (40 mL) at 0° C. is added, dropwise, chloromethylthiocyanate (5.0 grams, 0.046 mol). The resulting solution is allowed to warm to room temperature and is stirred for 2 hours. The reaction mixture is poured into 150 mL of water, followed by extraction with three 50 mL portions of dichloromethane. The combined organic extracts are washed with water and brine followed by drying (with sodium sulfate) and concentration. Recrystallization of the residue from dichloromethane/hexanes gives (bis(thiomethylthiocyanate)methylene)-propanedinitrile as fine yellow needles.
The recovered material weighs 3.3 grams and has a melting point of 143° to 146° C. A calculated overall yield of 67 percent is achieved.
The structure identity is confirmed by proton nuclear magnetic resonance spectroscopy ( 1 H), carbon nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR) and gas chromatography/mass spectrometry (GC/MS).
EXAMPLE 2
Preparation of Z-2,3-Bis(thiomethylthiocyanate)-2-Butenedinitrile
To a solution of Z-2,3-dimercapto-2-butenedinitrile-disodium salt, (4.3 grams, 0.023 mol) in dimethyl formamide (40 mL) at 0° C. is added dropwise, chloromethylthiocyanate (5.0 grams, 0.046 mol). The resulting solution is warmed to room temperature and is stirred for 2 hours. The reaction mixture is poured into 150 mL of water, followed by extraction with three 50 mL portions of dichloromethane. The combined organic extracts are washed with water, brine and dried (with sodium sulfate) and then concentrated. Recrystallization from dichloromethane/hexanes gives 2.62 grams (40 percent yield) of Z-2,3-bis(thiomethylthiocyanate)-2-butenedinitrile as tan colored prisms and has a melting point of 90° to 93° C.
ANTIMICROBIAL ACTIVITY
The compounds of this invention are useful as antimicrobial additives to such industrial products as styrene-butadiene latexes used for paper coatings, paints, inks, adhesives, soaps, cutting oils, textiles, and paper and pigment slurries. The compounds are also useful as antimicrobial additives in such personal care products as hand creams, lotions, shampoos, and hand soaps. A further advantage of this invention is its cost-effectiveness for applications which need to have an antimicrobial continuously replenished, such as in cooling towers and pulp and paper mills.
As appreciated in the art, the two compounds disclosed herein are not necessarily active at the same concentrations or against the same microbial species. That is, there is some compound-to-compound variation in antimicrobial potency and spectrum of antimicrobial activity.
The present invention is also directed to a method for inhibiting microorganisms which comprises contacting said microorganisms or habitat thereof with an effective amount of the compound of this invention.
The antimicrobial compounds of this invention may be added directly to aqueous formulations susceptible to microbial growth, either undiluted or dissolved in inert diluents such as organic solvents such as glycols, alcohols, or acetone. They may also be added alone or in combination with other preservatives.
As used herein, the term "microorganism" is meant to refer to bacteria, fungi, viruses, algae, subviral agents and protozoa.
As used herein, the term "antimicrobially-effective amount" refers to that amount of one or a mixture of both the compounds, or of a composition comprising such compound or compounds, of this invention needed to exhibit inhibition of selected microorganisms. Typically, this amount varies from providing about 1 part per million (ppm) to about 5,000 ppm by weight of the compound to a microbial habitat being contacted with the compound. Such amounts typically vary depending upon the particular compound tested and microorganism treated Also, the exact concentration of the compounds to be added in the treatment of industrial and consumer formulations may vary within a product type depending upon the components of the formulation. A preferred effective amount of the compound is from about 1 ppm to about 500 ppm, more preferably from about 1 ppm to about 50 ppm by weight, of a microbial habitat.
The term "microbial habitat" refers to a place or type of site where a microorganism naturally or normally lives or grows. Typically, such a microbial habitat will be an area that comprises a moisture, nutrient, and/or an oxygen source such as, for example, a cooling water tower or an air washing system.
The terms "inhibition", "inhibit" or "inhibiting" refer to the suppression, stasis, kill, or any other interference with the normal life processes of microorganisms that is adverse to such microorganisms, so as to destroy or irreversibly inactivate existing microorganisms and/or prevent or control their future growth and reproduction.
The antimicrobial activity of the compounds of the present invention is demonstrated by the following techniques.
TABLE I______________________________________Identification of Compounds Used inAntimicrobial Activity TestsCompound No. Chemical Identity______________________________________A Bis(thiomethylthiocyanate)methylene- propanedinitrileB Z-2,3-bis(thiomethylthiocyanate)- 2-butenedinitrile______________________________________
The minimum inhibitory concentration (MIC) for the compounds listed in Table I is determined for 9 bacteria, using nutrient agar, and 7 yeast and fungi, using malt yeast agar. A one percent solution of the test compound is prepared in a mixture of acetone and water. Nutrient agar is prepared at pH 6.8, representing a neutral medium, and at pH 8.2, representing an alkaline medium. The nutrient agars are prepared by adding 23 g of nutrient agar to one-liter of deionized water. In addition, the alkaline medium is prepared by adjusting a 0.04 M solution of N-[tris-(hydroxymethyl)methyl]glycine buffered deionized water with concentrated sodium hydroxide to a pH of 8.5. Malt yeast agar is prepared by adding 3 g yeast extract and 45 g malt agar per liter of deionized water. The specific agar is dispensed in 30 ml aliquots into 25×200 mm test tubes, capped and autoclaved for 15 minutes at 115° C. The test tubes containing the agar are cooled in a water bath until the temperature of the agar is 48° C. Then, an appropriate amount of the one percent solution of the test compound is added (except in the controls where no compound is added) to the respective test tubes so that the final concentrations are 500, 250, 100, 50, 25, 10, 5, 2.5, 1.0 and zero parts per million of the test compound in the agar, thus having a known concentration of test compound dispersed therein. The contents of the test tubes are then transferred to respective petri plates. After drying for 24 hours, the petri plates containing nutrient agar are inoculated with bacteria and those containing malt yeast agar are inoculated with yeast and fungi.
The inoculation with bacteria is accomplished by using the following procedure. Twenty-four hour-cultures of each of the bacteria are prepared by incubating the respective bacteria in tubes containing nutrient broth for 24 hours at 30° C. in a shaker. Dilutions of each of the 24 hour-cultures are made so that nine separate suspensions (one for each of the nine test bacteria) are made, each containing 10 8 colony forming units (CFU) per ml of suspension of a particular bacteria. Aliquots of 0.3 ml of each of the bacterial suspensions are used to fill the individual wells of Steer's Replicator. For each microbial suspension, 0.3 ml was used to fill three wells (i.e., three wells of 0.3 ml each) so that for the nine different bacteria, 27 wells are filled. The Steer's Replicator is then used to inoculate both the neutral and alkaline pH nutrient agar petri plates.
The inoculated petri plates are incubated at 30° C. for 48 hours and then read to determine if the test compound which is incorporated into the agar prevented growth of the respective bacteria.
The inoculation with the yeast and fungi is accomplished as follows. Cultures of yeast and fungi are incubated for seven days on malt yeast agar at 30° C. These cultures are used to prepare suspensions by the following procedure. A suspension of each organism is prepared by adding 10 ml of sterile saline and 10 microliters of octylphenoxy polyethoxy ethanol to the agar slant of yeast or fungi. The sterile saline/octylphenoxy polyethoxy ethanol solution is then agitated with a sterile swab to suspend the microorganism grown on the slant. Each resulting suspension is diluted into sterile saline (1 part suspension: 9 parts sterile saline). Aliquots of these dilutions are placed in individual wells of Steer's Replicator and petri plates inoculated as previously described. The petri plates are incubated at 30° C. and read after 48 hours for yeast and 72 hours for fungi.
Table II lists the bacteria, yeast and fungi used in the MIC. test described above along with their respective American Type Culture Collection (ATCC) identification numbers.
TABLE II______________________________________Organisms Used in the MinimumInhibitory Concentration TestOrganism ATCC No.______________________________________BacteriaBacillus subtilis (Bs) 8473Enterobacter aerogenes (Ea) 13048Escherichia coli (Ec) 11229Klebsiella pneumoniae (Kp) 8308Proteus vulgaris (Pv) 881Pseudomonas aeruginosa (Pa) 10145Pseudomonas aeruginosa (PRD-10) 15442Salmonella choleraesuis (Sc) 10708Staphylococcus aureus (Sa) 6538Yeast/FungiAspergillus niger (An) 16404Candida albicans (Ca) 10231Penicillium chrysogenum (Pc) 9480Saccharomyces cerevisiae (Sc) 4105Trichoderma viride (Tv) 8678Aureobasidium pullulan (Ap) 16622Fusarium oxysporum (Fo) 48112______________________________________
In Tables III and IV, the MIC values of the compounds described in Table I as compared to the MIC of a standard commercial preservative (DOWICIL™ 75, a trademark of The Dow Chemical Company, with 1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride as the active agent) are set forth for the nine bacteria organisms and six yeast/fungi organisms which are listed in Table II.
TABLE III__________________________________________________________________________Minimum Inhibitory Concentrations for Test Compoundsin Bacteria Species (in ppm) ORGANISMSCompound Bs Ea Ec Kp Pv PRD Pa Sc Sa__________________________________________________________________________DOWICIL™ 75pH 6.8 50 100 100 50 50 100 100 50 100pH 8.2 250 250 250 250 250 500 >500 100 250(A)pH 6.8 25 25 <10 <10 <10 250 250 <10 25pH 8.2 25 100 50 25 25 >500 >500 25 25(B)pH 6.8 50 250 100 25 100 500 250 50 25pH 8.2 50 250 250 100 250 500 250 250 50__________________________________________________________________________
TABLE IV__________________________________________________________________________Minimum Inhibitory Concentrations for TestCompounds in Yeast/Fungi Species (in ppm) ORGANISMSCOMPOUND An Ca Pc Sc Tv Ap Fo__________________________________________________________________________DOWICIL™ 75 >500 >500 >500 500 >500 >500 >500A 25 100 <10 50 50 50 25B 25 50 10 50 50 25 25__________________________________________________________________________ | Dimercapto-substituted dinitriles are prepared which correspond to the formula: ##STR1## wherein X represents: ##STR2## These compounds have been found to exhibit antimicrobial activity in industrial and commercial applications and compositions containing these compounds are so employed. | 0 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a vehicle passenger detection device and particularly to a vehicle passenger detection device that detects the presence of a passenger upon a seat.
[0003] 2. Background
[0004] Known examples of such a vehicle passenger detection device include, for example, the device taught by Japanese Unexamined Patent Publication No. 2000-258233. With such a vehicle passenger detection device, a strain gage-type weight measurement device 3 is provided between a seat frame 1 (or the lower rail of the seat slide rails) provided in the lower part of the seat and a seat bracket 2 attached to the floor panel.
[0005] This weight measurement device 3 consists of a base member 4 provided with a pin hole 4 a and slot 4 b , an arm 7 pivotally supported upon the base member 4 using a base pin 5 serving as the fulcrum (support axle) and a retainer 6 , a flat spring 10 that is attached to one end of the arm 7 with a bracket pin 8 and retainer 9 , a pin bracket 11 as a load transfer member and a strain gage-type load sensor 12 . In FIG. 1, F indicates the front of the vehicle while R indicates the rear of the vehicle.
[0006] With this device, when the load of the passenger upon the seat is transferred via the pin bracket 11 , flat spring 10 and bracket pin 8 to the end of the arm 7 , this arm 7 is pivotally supported by the base pin 5 , so it rocks about the base pin 5 , the motion of the other end of the arm 7 is transferred to the load sensor 12 and the load of the passenger is detected by the load sensor 12 . With this device, in order to prevent excessive rocking of the arm 7 , bushings are disposed between the arm 7 and base member 4 , and moreover, the base pin 5 on the fulcrum side is pivotally supported in the pin hole 4 a so that backlash does not occur.
[0007] However, with a weight measurement device such as that shown in FIG. 1, mechanical hysteresis occurs.
[0008] Mechanical hysteresis refers to a situation wherein, when the passenger exits the vehicle, the load on the seat is released and the seat returns to its original position, and at the stage when the load on the weight measurement device reaches a very small load of roughly 2 kg, for example, this very small load balances against the mechanical resistance of the moving parts within the weight measurement device, and thus the weight measurement device does not return to the zero position as its original position. As a result, even though the passenger is no longer present upon the seat, a constant load continues to be input to the load measurement device of the vehicle passenger detection device.
[0009] The results of detection by the vehicle passenger detection device are used to control airbag deployment, so the vehicle passenger detection device is required in order to determine the presence of a passenger upon the seat and whether the passenger is an adult or child. With a vehicle passenger detection device as described above, a determination is made among the states of no passenger present or an adult or child passenger present based on the load detected by the weight measurement device and predetermined threshold values.
[0010] Children are light in weight, so the threshold value for distinguishing between the states of no passenger present and a child passenger present is set to a relatively small value. For this reason, in the state in which mechanical hysteresis causes a constant load to be input to the load measurement device of the vehicle passenger detection device, if cargo is placed upon the seat, then the total load of the load due to the mechanical hysteresis and the load due to cargo may exceed the threshold value for distinguishing the state of no passenger present from the state in which a child passenger is present in the load measurement device of the vehicle passenger detection device. As a result, there is a problem in that the vehicle passenger detection device may erroneously determine that a child is sitting on that seat even though no passenger is present.
SUMMARY OF THE INVENTION
[0011] The present invention was accomplished in order to solve this problem and has as its object to provide a vehicle passenger detection device that is able to prevent erroneous determinations arising from mechanical hysteresis.
[0012] The present invention was achieved based on the discovery that although mechanical hysteresis occurs when a load is applied to a seat and this load is returned to zero, this mechanical hysteresis is eliminated when the seat is subjected to a certain amount of vibration.
[0013] The present invention thus provides a vehicle passenger detection device wherein the vehicle passenger detection device comprises: weight measurement means, provided with a weight sensor disposed between a seat and floor of a vehicle, that measures the load applied to the seat; fluctuation amplitude detection means that detects the amplitude of fluctuation in values measured by the weight measurement means; correction means that applies a negative correction to the value measured by the weight measurement means when the fluctuation amplitude is smaller than a stipulated value; and passenger presence determination means that determines the presence of a passenger upon the seat by comparing the value measured by the weight measurement means against a stipulated threshold value.
[0014] With the present invention having such a constitution, when the fluctuation of the value measured by the weight measurement device is determined to be less than a stipulated amplitude, residual hysteresis is assumed to be present, so the conditions for determining the presence of passengers are changed and the determination of the presence of passengers is performed under conditions with the effects of mechanical hysteresis eliminated. Thus, the detection of passengers can be performed accurately even in a range that is easily affected by mechanical hysteresis.
[0015] In a preferred embodiment of the present invention, the weight measurement means comprises a plurality of weight sensors, and the fluctuation amplitude detection means detects the amplitude of fluctuation in the values measured by the various weight sensors and further comprises correction control means that controls the negative correction when the amplitude of fluctuation of the values measured by at least one of the weight sensors is greater than said stipulated value.
[0016] Another embodiment of the present invention comprises: adult passenger determination means that compares the measured value against an adult passenger determination threshold value greater than the threshold value and thus determines if the passenger is an adult or child, and display means that, when the passenger presence determination means determines that a passenger is present and the adult passenger determination means determines that the passenger is a child, disables airbag deployment and activates an indicator that indicates that airbag deployment is disabled.
[0017] Another embodiment of the present invention is a vehicle passenger detection device where the vehicle passenger detection device comprises: weight measurement means, provided with a weight sensor disposed between a seat and floor of a vehicle, that measures the load applied to the seat; fluctuation amplitude detection means that detects the amplitude of fluctuation in values measured by the weight measurement means; and passenger presence determination means that determines the presence of a passenger by comparing the value measured by the weight measurement means against a stipulated threshold value, wherein: if the amplitude of fluctuation is greater than the stipulated value, the passenger presence determination means compares the value measured by the weight measurement means against a first threshold value to determine the presence of a passenger, and if the value measured by the weight measurement means is smaller than a stipulated value, the passenger presence determination means compares the value measured by the weight measurement means against a hysteresis threshold value greater than the first threshold value to determine the presence of a passenger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] [0018]FIG. 1 is a perspective exploded view showing a vehicle passenger detection device according to the background art and a preferred embodiment of the present invention.
[0019] [0019]FIG. 2 is a side view of a seat equipped with the vehicle passenger detection device according to a preferred embodiment of the present invention.
[0020] [0020]FIG. 3 is a block diagram showing the constitution of the vehicle passenger detection device according to a preferred embodiment of the present invention.
[0021] [0021]FIG. 4 is a flowchart showing the content of the passenger detection process performed by the CPU of the vehicle passenger detection device according to Preferred Embodiment 1 of the present invention.
[0022] [0022]FIG. 5 is a flowchart illustrating the airbag control process performed by the CPU of the vehicle passenger detection device according to Preferred Embodiment 1 of the present invention.
[0023] [0023]FIG. 6 is a flowchart illustrating a modification of the airbag control process according to Preferred Embodiment 1 of the present invention.
[0024] [0024]FIG. 7 is a flowchart illustrating the content of the passenger detection process performed by the CPU of the vehicle passenger detection device according to Preferred Embodiment 2 of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Preferred embodiments of the present invention will be explained with reference to the drawings.
[0026] [0026]FIG. 2 is a schematic side view of a vehicle seat 20 incorporating the weight measurement device and other components of the vehicle passenger detection device according to preferred embodiments of the present invention.
[0027] This seat 20 consists of a seat cushion 22 , seat back 24 and headrest 26 , being a passenger seat. Below the seat 20 is disposed a seat bracket 30 secured to the floor panel 28 of the vehicle. To this seat bracket 30 are attached a left/right pair of base members 32 (only one of which is shown) extending toward the front and rear of the vehicle. Each of the base members 32 has the same construction as the base member 4 of FIG. 1. Each of these base members 32 is attached to seat slide rails 34 extending toward the front and rear of the vehicle.
[0028] The seat slide rails 34 consist of an upper rail 34 U secured to the bottom of the seat cushion 22 and a lower rail 34 L secured to the base members 32 . The upper rail 34 U and lower rail 34 L are assembled such that they are able to move relative to each other. With this construction, the seat 20 is mounted such that it is able to move forward and backward with respect to the floor panel 28 via the seat slide rails 34 consisting of an upper rail 34 U and lower rail 34 L.
[0029] As shown in FIG. 2, a load sensor 36 is disposed between the lower rail 34 L and base members 32 . This load sensor 36 is the same as load sensor 12 of FIG. 1, and together with other constituent members (not shown) constitutes the same weight measurement device as the weight measurement device 3 of FIG. 1. Accordingly, this embodiment is constituted such that the load applied to the seat 20 can be measured by means of the weight measurement device including the load sensor 36 . In addition, to one weight measurement device each is attached to the front and back of each of the base members 32 , so a total of four devices are attached to one seat 20 .
[0030] [0030]FIG. 3 is a schematic block diagram showing the constitution of the vehicle passenger detection device according to the present embodiment. In the present embodiment, a CPU 38 constituting the vehicle passenger detection device is constituted such that it is able to perform airbag deployment control in addition to the passenger detection process.
[0031] The CPU 38 is constituted so as to accept inputs from a G sensor (collision sensor) 40 and a buckle switch 42 that detects whether the seat belt is buckled. In addition, to the CPU 38 is connected ROM 44 for storing a passenger presence determination program and airbag deployment program and RAM 46 for storing the required data. The CPU 38 is further constituted such that it can send output signals to an inflator driver 50 that inflates an airbag 48 , a first indicator 52 that indicates the presence of a passenger and a second indicator 54 that indicates that the passenger is a child so the airbag is in the disabled state. In this embodiment, the first and second indicators are constituted such that they are lamps visible to the passenger.
[0032] The content of the processes performed by the CPU 38 of the vehicle passenger detection device of the present embodiment will be described with reference to flowcharts. The process given below is executed immediately upon the ignition switch being turned ON.
[0033] [0033]FIG. 4 is a flowchart showing the content of the passenger detection process performed by the CPU 38 . In Step S 1 , input the seat load W detected by the load sensors 36 and the amplitude of fluctuation of the output value of each load sensor. In the present embodiment, the seat load W is taken to be the sum of the values of the seat loads from each of the four load sensors 36 . In addition, the fluctuation amplitude is taken to be the difference between the maximum value and minimum value of the output of each load sensor during a stipulated period of time, e.g., 750 ms.
[0034] Next, in Step S 2 , input a signal from the buckle switch 42 . Next, in Step S 3 , read from RAM 46 the first threshold value W 1 which is a threshold value for distinguishing between the state in which no passenger is present and the state in which the passenger is a child (the child presence determination threshold value) and, in Step S 4 , read the second threshold value W 2 which is a threshold value for distinguishing whether a passenger is an adult or child (the adult presence determination threshold value). In the present embodiment, W 1 is set to 7 kg and W 2 is set to 35 kg.
[0035] Next, advance to Step S 5 and determine whether or not the seat load W is greater than the second threshold value W 2 . If the result of Step S 5 is YES, advance to Step S 6 where the passenger is determined to be an adult.
[0036] If the result of Step S 5 is NO, advance to Step S 7 and determine whether or not the amplitude of fluctuation in the output value of at least one of the load sensors is greater than a stipulated value (e.g., 2 kg). If the output value of at least one of the load sensors 36 fluctuates by more than the stipulated value, then by this fluctuation it may be assumed that the mechanical hysteresis within the weight measurement device has been eliminated. Accordingly, with the passenger detection device according to the present embodiment, the presence of mechanical hysteresis is assumed based on the amplitude of fluctuation in output values from the load sensor 36 .
[0037] If the result of Step S 7 is NO, or namely the amplitude of fluctuation in the output values from all load sensor 36 is smaller than the stipulated value, residual mechanical hysteresis is assumed to be present, so advance to Step S 8 and apply a negative correction that subtracts from the seat load W a correction value a equivalent to the mechanical hysteresis (e.g., 2 kg).
[0038] If the result of Step S 7 is YES and the processing of Step S 8 is complete, advance to Step S 9 and determine whether or not the seat load W is greater than the first threshold value W 1 used to determine the presence of a child.
[0039] If the result of Step S 9 is NO, advance to Step S 10 and determine whether or not the buckle switch is ON. If the result of Step S 10 is YES, the load on the seat is small but the seat belt is buckled, so a child seat is assumed to be installed. Accordingly, the passenger is determined to be a child in Step S 11 . In addition, if the result of Step S 10 is NO, no passenger is determined to be present in Step S 12 .
[0040] In addition, if the result is YES in Step S 9 , the seat load W is in the range equivalent to the weight of a child, so advance to Step S 11 and the passenger is determined to be a child.
[0041] Next, the airbag control process performed by the CPU 38 will be described with reference to the flowchart shown in FIG. 5.
[0042] In Step S 20 , read the results of determination according to the process of FIG. 4 (adult passenger, child passenger, no passenger) and in Step S 21 read the signal from the G sensor 40 .
[0043] Next, in Step S 22 , determine whether or not no passenger is present upon the seat based on the results read in Step S 20 . If the result of Step S 22 is YES, namely no passenger is present, advance to Step S 23 and turn off first indicator 52 which reports the presence of a passenger.
[0044] If the result of Step S 22 is NO, namely an adult or child passenger is present, advance to Step S 24 and turn on the first indicator. Next, advance to Step S 25 , determine whether or not the passenger upon the seat 20 is an adult, and if YES, namely the passenger is an adult, perform the process of enabling airbag deployment in Step S 26 , and turn off (OFF) the second indicator 54 in Step S 27 .
[0045] Furthermore, advance to Step S 28 and determine whether or not the output value G of the G sensor 40 is greater than the airbag deployment threshold value Go. If the result of Step S 28 is YES, then advance to Step S 29 and deploy the airbag 48 via inflator driver 50 . If the result of Step S 28 is NO, then return to Step S 20 .
[0046] On the other hand, if the result of Step S 25 is NO and the processing of Step S 23 is complete, either no passenger is present or the passenger is a child so advance to Step S 30 , perform the process of disabling airbag deployment and advance to Step S 31 . In Step S 31 , if the passenger is a child, turn on (ON) the second indicator 54 which indicates that airbag deployment is disabled because the passenger is a child and return to Step S 20 . If no passenger is present, do not turn on the second indicator 54 in Step S 31 .
[0047] With the present embodiment, if the amplitude of fluctuation of the output value of one of the load sensors among the plurality of load sensors is greater than the stipulated value, the negative correction is controlled, so it is possible to control wasteful corrections.
[0048] In addition, with this constitution, the state of normal operation of the passenger detection device can be confirmed by means of the first indicator 52 .
[0049] It should be noted that configuration can be adopted wherein the step of reading the signal from the G sensor 40 in Step S 21 is performed immediately before the step of comparing the output value G of the G sensor 40 against the airbag deployment threshold value Go in Step S 28 as shown in the flowchart of FIG. 6.
[0050] A vehicle passenger detection device according to Preferred Embodiment 2 of the present invention will now be described. The basic constitution of this vehicle passenger detection device is the same as that of the vehicle passenger detection device according to Preferred Embodiment 1 above. The differences from Preferred Embodiment 1 lie in the content of the passenger detection process. The passenger detection process of Preferred Embodiment 2 will be described with reference to the flowchart of FIG. 7 which shows the passenger detection process performed by the CPU of Preferred Embodiment 2.
[0051] First, in Step S 40 , input the seat load W detected by the load sensors 36 and the amplitude of fluctuation of the output value of each load sensor. In the present embodiment also, the seat load W is taken to be the sum of the values of the seat loads from each of the four load sensors 36 . In addition, the fluctuation amplitude is taken to be the difference between the maximum value and minimum value of the output of each load sensor during a stipulated period of time, e.g., 750 ms.
[0052] Next, in Step S 41 , input a signal from the buckle switch 42 . Next, in Step S 42 , read from RAM 46 the first threshold value W 1 which is a threshold value for distinguishing between the state in which no passenger is present and the state in which the passenger is a child (the child presence determination threshold value), in Step S 43 read a hysteresis threshold value W h greater than the first threshold value and in Step S 44 read the second threshold value W 2 which is a threshold value for distinguishing whether a passenger is an adult or child (the adult presence determination threshold value), respectively. In the present embodiment, W 1 is set to 7 kg, W h is set to 9 kg and W 2 is set to 35 kg.
[0053] Next, advance to Step S 45 and determine whether or not the seat load W is greater than the second threshold value W 2 . If the result of Step S 45 is YES, advance to Step S 46 where the passenger is determined to be an adult.
[0054] If the result of Step S 45 is NO, advance to Step S 47 and determine whether or not the amplitude of fluctuation in the output value of at least one of the load sensors is greater than a stipulated value (e.g., 2 kg). If the output value of at least one of the load sensors 36 fluctuates by more than the stipulated value, then by this fluctuation it may be assumed that the mechanical hysteresis within the weight measurement device has been eliminated. Accordingly, with the passenger detection device according to the present embodiment, the presence of mechanical hysteresis is assumed based on the amplitude of fluctuation in output values from the load sensor 36 .
[0055] If the result of Step S 47 is NO, or namely the amplitude of fluctuation in the output values from all load sensor 36 is smaller than the stipulated value (e.g., 2 kg), residual mechanical hysteresis is assumed to be present, so advance to Step S 48 and determine whether or not the seat load W is greater than the hysteresis threshold value W h which is greater than the first threshold value W 1 used to determine the presence of a child. If the result of Step S 38 is YES, advance to Step S 49 where the passenger is determined to be a child.
[0056] If the result of Step S 48 is NO, advance to Step S 50 and determine whether or not the buckle switch is ON. If the result of Step S 50 is YES, the load on the seat is small but the seat belt is buckled, so the state in which a child seat is assumed to be installed. Accordingly, advance to Step S 49 where the passenger is determined to be a child.
[0057] If the result of Step S 48 is NO, advance to Step S 50 and determine whether or not the buckle switch is ON. If the result of Step S 50 is YES, the load on the seat is small but the seat belt is buckled, so a child seat is assumed to be installed. Accordingly, advance to Step S 49 and determine the passenger to be a child. In addition, if the result of Step S 50 is NO, advance to Step S 51 and determine no passenger to be present.
[0058] On the other hand, if the result in Step S 47 is YES, advance to Step S 52 and determine whether or not the seat load W is greater than the first threshold value W 1 . If the result in Step S 52 is YES, advance to Step S 49 and determine the passenger to be a child. In addition, if the result in Step S 52 is NO, advance to Step S 50 and determine whether a child is present or no passenger is present based on the buckle switch.
[0059] With this constitution, a hysteresis threshold value W h greater than the first threshold value W 1 used to determine the presence of a child is set, so if hysteresis is assumed to be remaining, the seat load W is compared against the hysteresis threshold value W h to make a determination with the effects of mechanical hysteresis eliminated.
[0060] The invention is not limited to only the constitution of the preferred embodiments described above.
[0061] The first and second indicators in these preferred embodiments are constituted so as to notify the passenger of the indicated content by a lamp being turned on or off, but it is also possible to notify the passenger of the indicated content by turning on lamps of different colors. | The present invention has as its object to provide a vehicle passenger detection device that is able to prevent erroneous determinations arising from mechanical hysteresis. The present invention provides a vehicle passenger detection device comprising: weight measurement means, provided with a weight sensor disposed between a seat and floor of a vehicle, that measures the load applied to the seat; fluctuation amplitude detection means that detects the amplitude of fluctuation in values measured by the weight measurement means; correction means that applies a negative correction to the value measured by the weight measurement means when the fluctuation amplitude is smaller than a stipulated value; and passenger presence determination means that determines the presence of a passenger upon the seat by comparing the value measured by the weight measurement means against a stipulated threshold value. | 1 |
This application claims the benefit of International Application No. PCT/US97/24043, filed Dec. 27, 1997, which claims the benefit of U.S. Provisional Application No. 60/034,799, filed Dec. 31, 1996.
DESCRIPTION
1. Technical Field
The present invention relates generally to a drill string apparatus for use in drilling operations, and more particularly to an apparatus and method for selectively locking an inline swivel to permit rotational movement of the drill string.
2. Background Art
In wireline operations, it is often desirable to selectively allow the drill string to rotate freely while the wireline operator manipulates the wireline.
Previously, if the operator desired to rotate the drill string during wireline operations, the wireline was pulled from the well bore and the entry devices were disengaged from the drill string. The removal of the wireline could be avoided if an inline swivel was placed in the drill string between the wireline device and the rotary table. This arrangement would permit rotation to be accomplished with a wireline in place, but effectively disengaged the top-drive unit from its preferred role of providing both lifting power and rotation to the drill string.
DISCLOSURE OF INVENTION
The invention disclosed herein provides an apparatus which would allow the connection of various wireline devices 106 to be placed in the drill string 100 between the top drive unit 102 and the rotary table 114 of a conventional drilling rig throughout wireline operations. Such devices 106 as the Boyd Borehole Drill Pipe Continuous Side Entry Or Exit Apparatus (such as described in U.S. Reissue Pat. No. 33,150) or applicant's Top Entry Sub Arrangement (as described in U.S. Pat. No. 5,284,210) may both be utilized for various wireline operations.
Referring to FIG. 4 , the invention is a lockable in-line swivel device 110 which is selectively engaged by the operator to permit or inhibit rotational movement provided by a top drive unit 102 to be transmitted through the swivel 110 to the pipe string 112 and to allow disengagement of the locked swivel 110 so that rotation may be accomplished by the rotary table 114 simultaneously with the wireline operations.
Accordingly, it is the primary purpose of the invention disclosed herein to provide an apparatus and method which permits the wireline entry devices 106 described above to be left in the drill string 100 during all operations involving the wireline operation. This avoids the time consuming makeup and disengagement of the entry tools 106 required to safely permit entry of the wireline into the well bore. If rotation and longitudinal movement is desired with the invention disclosed herein, the wireline alone is removed from the wellbore, but the entry tool 106 remains in place and the swivel 110 is locked to provide transmission of all rotation through the swivel 110 into the pipe string 112 .
At other times, the operator using a top-drive unit 102 may desire to pick up the drill string 100 and yet maintain torque which has been put into the pipe string 112 in pipe recovery operations. This is best done by engaging the swivel 110 in locked position and picking up with the top drive unit 102 . As the torque is worked through the drill string 100 , additional wireline operations may be desired. In this eventuality, the operator would set the drill string 100 down, disengage the swivel 110 , continue to rotate with the rotary table 114 and continue the wireline operations.
Using prior conventional technology, the drill pipe was separated and raised high above the rig floor on each run in order to change out tools. Although the pipe can be rotated, the operator could not circulate or reciprocate the pipe during these periods. Circulation was achieved by adding a pump-in sub and another T.I.W. safety valve immediately above the existing T.I.W. valve; which, however, put the disconnect or break point between the upper T.I.W. valve and the swivel several feet above the rig floor creating a safety hazard while operating the rig tongs.
Further, since the tool strings must be stripped in and out beneath the upper assembly, a lubricator or tool protection device could not be used and all tools and explosives were brought onto the rig floor unshielded and unconfined. In the event of an inadvertent detonation of the explosive string shot or perforators, all personnel on the rig floor were totally exposed to this unnecessary life-threatening hazard.
Once rigged-up and going in the hole using conventional technology such as the Boyd side-entry sub, the wireline passed through the acute angle in the side entry sub. This caused excessive wearing of the wireline and creates sever grooving in the sub. The single rubber pack-off, which is commonly used with this system, is very susceptible to leaking and/or line gripping and stoppage during pump-down operations. The system cannot be used when working under surface pressure and with the need to utilize a grease injector and wireline blow out preventers (BOPs).
During pipe recovery operations, both right and left-hand torque must be worked down-hole using the rig tongs. This is a procedure has long been recognized to be one of the greatest safety hazards to be encountered during pipe recovery operations. When using this prior technology, pipe tongs were attached to the drill string and secured to the rig to hold torque that had been put into the drill string from the rotary table or top drive unit. With the present invention, this torque can be maintained while continuing circulation and wireline operation.
These and other objects, features, and advantages of the present invention will become apparent from the drawing and the descriptions given herein.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an sectional view of the tool of the invention.
FIG. 2 is detailed view of the bearing arrangement of the invention encircled by ellipse of FIG. 1 .
FIG. 3A is a cross-sectional view of the upper spline engagement surfaces along line 3 A— 3 A of FIG. 1 .
FIG. 3B is a cross-sectional view of the lower spline engagement surfaces along line 3 B— 3 B of FIG. 1 .
FIG. 4 is a graphical representation of a drill string 100 .
BEST MODE FOR CARRYING OUT THE INVENTION
In FIG. 1 , the locking swivel apparatus 110 comprises a retainer sub 1 which is provided with means 10 for making a threaded connection with standard tubular members, and is threadably engaged with a lower body 3 to retain a locking mandrel 2 . The locking mandrel 2 is provided with splines 16 and splines 18 to engage splined surfaces 20 and 21 respectively formed both in the swivel mandrel 5 and in the lower body 3 for locking the swivel to the lower body to prevent rotation of the pipe string 112 (See FIG. 4 ) which would be connected to threads 10 ′.
The retainer sub 1 , locking mandrel 2 , and lower body 3 of the lockable swivel apparatus 110 engage the top sub 4 of an inline swivel. Brass packing rings 27 and washpipe packing 26 seal swivel mandrel 5 permitting fluid communication through the annulus of the inline swivel apparatus without leakage. Swivel mandrel 5 is secured to the circumferentially spaced brass wear ring 31 , bearing 29 , packing 28 and 30 by a bearing retainer nut 6 , which is threadably engaged on the top sub 4 by threads 33 and 33 ′. As shown in FIG. 2 , the wear ring 31 has seal means 36 , 37 , which contact the bearing retainer nut 6 . The lower body 3 is threadably engaged into the top sub 4 of the inline swivel. The swivel mandrel 5 of the inline swivel is provided with inner splines 21 to engage the outer splines 18 formed on the lower end of the locking mandrel 2 which extends through the lower body 3 and top sub 4 .
Hydraulic fitting ports 40 and 41 provided in the lower body 3 are disposed on either side of a dynamic seal means 17 in a chamber formed between exterior of the locking mandrel 2 and the interior wall 43 of the lower body 3 to move the locking mandrel 2 either up or down and thereby into or out of engagement with the splines 21 on the swivel mandrel 5 and the splines 20 in the lower body 3 . The locking mandrel 2 moves up or down as provided and is stopped by shoulder 15 from moving into retainer sub 1 .
Washpipe packer or seal means 45 and 46 are provided to make a hydraulic seal in chamber 43 ′ to enable an operator on the rig floor 116 to selectively move the locking mandrel 2 into and out of engagement with the swivel mandrel and to thereby control undesired rotation of the pipe string 112 by actuating a hydraulic pump.
In the preferred embodiment, standard hydraulic lines are attached to hydraulic fitting ports 40 and 41 and connected by hydraulic lines to a pump controlled by the operator in a manner well known to those in the industry. The operator switches the flow of hydraulic fluid to port 40 if locking of the swivel is desired, and to port 41 if unlocking of the swivel is desired.
FIG. 2 of the drawings shows the detail of the bearing surfaces disposed around the swivel arrangement. FIGS. 3A and 3B are cross sectional views of the cooperating engagement surfaces or splines of the locking mandrel and the swivel mandrel.
When used in conjunction with wireline services on directional drilling operations, the magnetic or gyro-type tools have direct entry into the pipe string 112 through the top entry sub (a wireline access sub 106 ). Once the tools have been landed in the down-hole-guide sub, or in the wet-connect sub, the pipe string 112 can then be oriented using the rotary table 114 , while maintaining the swivel 110 in the unlocked position. Once the desired orientation has been attained, the pipe can then be held in position by locking the swivel and engaging the back-brake on the top drive unit 102 .
Should minor adjustments in the orientation be required, this can be easily accomplished since the locking mechanism in the swivel 110 incorporates a splined shaft which provides eighty three separate orientations per revolution. Utilization of this package enables drilling two or three joint per connection, depending on rig height, and eliminates holding the back-torque with the rig tongs.
In pipe recovery operations, once the downhole package has been assembled, the wireline tools always have direct entry into the pipe string 112 which eliminates having to separate and re-connect the pipe string 112 each run. Also, the tools can be fully lubricated which minimizes any bending, flexing or jarring of sensitive instrumentation. All explosive devices, such as string shots, cutters, severing tools and perforating guns are contained within the lubricator while in close proximity of the rig floor 116 . This minimizes exposure to potential injury in the event of an inadvertent detonation. The assembly enables operation under surface pressure, while performing pump-down operations, and while employing a grease injector system. Between wireline runs, the operator retains the ability to continue circulation and reciprocation of the pipe string 112 , thus preventing additional subsidence and sticking. During actual operations both make-up and reverse torque can be applied to the pipe string 112 and worked-down without utilizing the rig tongs. Prior to the ability to maintain the torque by setting the swivel 110 in the locked position, torque was maintained on the drill string by attaching pipe tongs to the string and cabling the end of the tong to the drilling structure while the operator reciprocates and manipulates the string. The disengagement of the pipe tong cabling while torque was being applied caused the tongs and cabling to dangerously rotate rapidly around the rig floor.
During pipe recovery operations, the wireline engineer must apply right hand, “make-up,” torque to the pipe string 112 and work it down in order to assure that the entire string is sufficiently tight before applying the left hand, “back off,” torque. With the pipe string 112 setting on the slips in the rotary table 114 , usually at neutral weight, the right hand torque is applied to the pipe string 112 in an amount less than the full make-up torque of the string and then releasing or relaxing the brake on the pipe string 112 . Non-absorbed torque will “come back.” This process is then repeated three to four times, with each iteration providing greater amounts of torque, until a predetermined amount based upon the recommended maximum torque load for the type of pipe and connections has been reached. The drilling engineer also uses the behavior of the pipe string 112 during this process to determine the amount of torque the hole is “trapping” or whether the torque is being distributed evenly through-out the pipe string 112 or encountering premature build up because of angle changes, dog legs, etc.
With the right hand torque being held securely with the rotary back-brake or the rotary lock, the operator switches the manual control valve on the hydraulic pump from the open/unlocked position to the closed/locked position to begin closing the locking mechanism in the swivel 110 . The operator should count the strokes and to observe the sudden pressure increase. If the number of strokes and the pressure change are consistent with the results experienced in the installation phase, the internal lock is completely closed. To assure that the swivel 110 remains in locked position, it is recommended that approximately 500 pounds of back pressure against the lock be maintained.
Referring to FIG. 4 after determining that the back-brake on the top drive unit 102 is securely locked, the operator commences releasing the rotary table 114 back-brake and slowly transfers the pipe torque to the top drive unit 102 . When the torque is being held with the rotary lock, engage the top drive and slowly increase the amperage until the torque is transferred and the rotary lock can be released. Once all the torque has been transferred to the top drive unit 102 , the wireline access port will become shifted approximately 10.8 degrees to the left of true alignment. However, in this procedure the port will not shift if using a single joint but will shift 10.8 degrees to the right if using a lubricator joint 108 . This is predicated on having one round per thousand in the drill pipe and the shifts are directly proportional to the amount of torque that is being transferred from the drill pipe into the assembly joint 104 between the top entry adapter sub (a wireline access sub 106 ) and the top drive unit, or the lubricator joint between the top entry sub and the swivel 110 .
Once satisfied that the pipe string 112 has been sufficiently tightened to the point of accepting left-hand torque without breaking pre-maturely, the pipe string 112 can be placed back on the slips in the rotary table 114 . The back-brake or the lock on the rotary table 114 should then be engaged.
With the weight of the pipe string 112 now resting on the rotary table 114 , the torque being held with the top drive unit 102 can be slowly transferred to the rotary table 114 .
With the torque transferred and the top drive unit 102 disengaged, the operator switches the controls on the hydraulic pump and opens or “unlocks” the swivel 110 . As before, the operator should count the strokes and watch the pressure to assure that the swivel 110 is totally open, or “unlocked.” Again, it is recommended that approximately 500 pounds of back pressure be maintained to assure that swivel 110 remains in the open or “unlocked” position. The wireline access sub 106 should then be realigned with the derrick sheave and the top drive unit 102 relocked. The torque can then be released with the rotary table 114 . At this point, the engineer may elect to reciprocate the pipe string 112 in order to work out any remaining trapped torque prior to running the free point or other services.
The invention also enables rotating, circulating and reciprocating the pipe while running and pumping-down various wireline tools and performing various services, i.e., end-of-hole gyros, “measure-while-drilling” (M-W-D) retrieval tools, pipe recovery service tools, gamma ray logging devices or total “vertical depth” (T.V.D.) devices and other logging or perforating service tools.
Since the package can be assembled in a variety of configurations, customer preference, operating conditions and job requirements, whether involving directional drilling, pump downs, grease injectors, MWD retrieval, coil tubing or pipe recovery, will strongly influence which configuration is most advantageous for the job to be performed.
Once the chosen packages described above have been installed and tightened, the hydraulic hoses should be attached to the locking swivel 110 and the hand pump. The hoses, the swivel and the hand pump have mated quick-connects which assures that the labeling on the hand pump, closed/locked and open/unlocked corresponds correctly with the direction of movement and position of the internal locking mechanism within the swivel 110 .
Lock the rotary table 114 , or attach the back-up rig tongs to the joint of pipe in the rotary table 114 , and the assembly can be tighten to maximum torque allowed using the top drive unit 102 .
Engage the top drive unit 102 and slowly increase the amperage until the maximum foot pounds of torque allowed for the particular drill pipe being used in the upper assembly has been reached. Reduce the amperage to zero and then increase back to maximum allowed amperage at least one or two more times.
Once the assembly has been properly tightened and the top drive amperage reduced to zero, unlock the rotary, or release the back-up tongs, and then open, “unlock”, the swivel.
Use the top drive unit 102 and slowly orient the upper assembly until the wireline access port in the top entry sub (a wireline access sub 106 ) is in perfect alignment with the wireline sheave in the derrick. The top drive unit 102 should then be locked in this alignment and secured so as to prevent inadvertent unlocking.
Upon making one final check and assuring that the top drive unit 102 is locked in the aligned position and the swivel 110 is in the unlocked position, the assembly will be ready to begin operations. | A lockable swivel ( 4 ) for use in drilling applications which allows the operator to selectively engage and disengage the swivel ( 4 ). The lockable swivel ( 4 ) is comprised of a locking mandrel ( 7 ) carried in a body ( 3 ) which engages, upon actuation, splined surfaces ( 20, 21 ) within the swivel mandrel ( 5 ) thereby locking the two together. Various methods for the use of the lockable swivel ( 4 ) in wireline and other drilling operations are demonstrated. | 4 |
This invention relates to a method and apparatus for forming belt loops and transferring the formed loop to a sewing station where the loop may be stitched to the waistband of a pair of trousers. The invention is particularly useful in sewing belt loops onto the waistbands of trousers of the blue jeans type.
BACKGROUND OF THE INVENTION
Forming belt loops and attaching them to the waistband of a pair of trousers is a complex and labor intensive task if performed by hand. For this reason, there has been great interest in automating this operation as much as possible. Apparatus is known for automatically forming belt loops and feeding them to the waistband of a pair of blue jeans, for example. Although various types of this apparatus have been used commercially, they have not been entirely satisfactory. One problem that has arisen with the use of known types of beltloop forming and feeding apparatus is that the folded-under part at the ends of the length of beltloop material are longer than desired. After stitching the beltloop to the trousers, the free ends extend considerably beyond the stitching. It presently is common practice to pre-wash or stone-wash the jeans after completion, but before shipping from the factory. This washing process, and subsequent washings by the wearer, cause the free ends of the belt loops to become floppy and frayed. This is unsightly and undesirable in the very competitive jeans market where the appearance of quality is important.
To overcome the fraying of the beltloop ends, various different approaches have been tried, all requiring additional handling, additional equipment, and further expense. For example, one solution has been to manually cut off the extra lengths at the ends of the stitched beltloop. Some manufacturers dip the beltloop ends in a plastic substance that cures to prevent the ends from fraying. Other manufacturers have included a plastic material in the beltloop material. When the material is cut to desired lengths with a hot knife, the plastic melts in such a manner as to "seal" the ends to prevent fraying. Others have used a special knife that cuts the beltloop ends on the bias in such a manner as to minimize fraying.
An additional problem has arisen in finished jeans because of the way in which the folded-under ends of the belt loops have been formed. Known apparatus for forming the folded-under ends includes two spaced fingers that receive a beltloop end therebetween. One finger is rotated about the other, and in doing so, bends the beltloop material around the stationary finger. Not only does this operation form a folded-under end that is longer than necessary, but it has a tendency to stretch the beltloop material in the direction of its length. Even after stitching of the beltloop to the waistband, the cloth remains in its stretched condition. After washing, the formerly stretched material tends to bulge outwardly and the belt loops will not lie flat against the waistband. This is unsightly and detracts from the image of a quality product.
The apparatus and method of this invention overcome the problems mentioned above by automatically forming and feeding beltloops having shorter folded-under ends that are closely adjacent the stitching. In the prior art beltloop folding apparatus, the folded-under ends ranged in length from 7/16 to 1/2 inch. With my invention, I am able to form belt loops with only approximately 1/4 inch folded-under ends This substantially eliminates the problem of elongated frayed ends of the belt loops. Furthermore, when it is considered that each pair of jeans has seven belt loops, and approximately 450 million pairs of jeans were manufactured this past year, the amount of cloth that can be saved by the use of this invention is substantial.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described by referring to the accompanying drawing wherein:
FIG. 1 is a simplified perspective illustration of the beltloop forming and feeding apparatus of this invention;
FIGS. 2 and 3 are, respectively, simplified front and side illustrations of the apparatus of FIG. 1;
FIGS. 4 and 5 are, respectively, simplified end and top views of the beltloop material feeding mechanism and knife mechanism that is part of the apparatus of FIG. 1;
FIG. 6 is a simplified illustration of the puller clamp assembly that pulls out a desired length of beltloop material from a continuous supply of the material;
FIG. 7 is a simplified illustration of the transfer clamps assembly that is part of the apparatus of FIG. 1;
FIG. 8 is a simplified illustration of one of the loop former devices of the apparatus of FIG. 1;
FIG. 9 is a simplified illustration of the feeder clamps assembly that receives a folded beltloop and feeds it to a sewing station; and
FIGS. 10-22 are simplified illustration that show the relevant apparatus and assemblies of the invention during various stages of the operation of forming a beltloop from a continuous supply of beltloop material and feeding it to a sewing station on the base of a twin-needle sewing machine.
DESCRIPTION OF PREFERRED EMBODIMENT
In the following description, and in the claims, the term "beltloop material" is used. By this term I mean a continuous strip of beltloop that is finished except for cutting to a desired length and forming the folded-under ends prior to stitching onto a waistband. As is known in the art, the continuous strip is formed by splicing together shorter lengths of the beltloop material.
In order to better understand the detailed description that follows, a brief summary of the overall operation of the apparatus of this invention first will be given. Referring to FIG. 2 for this preliminary summary, a beltloop feeder and cutoff subassembly A feeds about 3/8 inch of material toward the open central region of the figure and the puller subassembly B grabs the free end and pulls it out to the left a predetermined distance. The pulled-out beltloop material is clamped by two clamps of the transfer clamps subassembly C and the puller releases the free end. Knife blade 78 of the feeder and cutoff subassembly A cuts off the pulled-out beltloop material to a desired length. The transfer clamps subassembly C then raises up and causes the two loop formers D to fold the free ends of the beltloop under the remainder of the beltloop. Feeder clamps subassembly E picks up the folded beltloop from the loop formers D and feeds it to the sewing station at an adjacent sewing machine.
Continuing now with a detailed description of the various subassemblies of the apparatus of this invention, the various subassembles are mounted on a horizontally extending the base 10. Beltloop material is supplied in a continuous strip that is wound on a reel which is mounted near the bottom of the apparatus, but which is not illustrated in the drawings. As seen in FIGS. 1, 2, and 5, the beltloop material enters the feed and cutoff subassembly A between a ramp 14 on the right end of the subassembly base plate 16 and the hinged end 20 of swing arm 22. The right end of the swing arm pivots on a pivot pin 25 that is supported between the spaced posts 26 that extend upwardly from base plate 16. The beltloop material passes horizontally across the midregion of base plate 16 and under a knurled idler wheel 30 which has single direction roller clutch. As best seen in FIG. 2, knurled wheel 30 is rotatably mounted in bracket 32 by means of axle 31 and the bracket 32 in turn is mounted for free pivotal movement on a pivot pin 34. The right end of leaf spring 36 is fixed to base plate 16 by means of knob 40 that has a stem 42 threaded into base 16. The left end of the spring rides on top of axle 31 and resiliently holds knurled wheel 30 in contact with beltloop material 12.
Beltloop material 12 continues to the left end of base plate 16 and passes between upper grooved idler wheel 50 and driven knurled wheel 52. Grooved wheel 50 is rotatably mounted between the tines 53a and 53b of the forked end of swing arm 22. Driven knurled wheel 52 is mounted on a one-way clutch that permits rotation of wheel 52 in the counterclockwise direction, FIG. 2, but prevents rotation of the wheel in the opposite direction. A suitable one-way clutch is sold under the trademark SURE-LOCK roller clutch, part number NRC-4, by Winfred M. Berg, Inc., East Rockaway, N.Y. This same clutch may be used for idler wheel 30.
Grooved wheel 50 is resiliently held in contact with the top surface of the beltloop material by means of an arrangement that includes an apertured block 54 that is attached to the rear of fork tine 53b. A threaded bolt 55 passes freely through block 54 and is threaded into base plate 16. Bolt 55 retains a helical compression spring 57 between the head of the bolt and the block 54 to resiliently urge the block 54, and thus grooved wheel 50, downwardly.
As best seen in FIGS. 1 and 5, driven axle 56 of knurled wheel 52 is fixedly secured in one end of crank arm 58 and thus is rotated by the crank arm. The opposite end of crank arm 58 is pivotally connected to the fork or clevis 60 that is connected to the end of piston rod 62 of pneumatic cylinder 64. The conventional fluid ports of the cylinder are represented at 66. The right end of cylinder 64 is secured to base plate 16 by a bracket 67.
When rod 62 is withdrawn into cylinder 64, crank arm 58 rotates in the counterclockwise direction and causes driven wheel 52 to rotate in that same direction. The extension of piston rod 62 of cylinder 64 causes crank arm 58 and axle 56 to rotate in the clockwise direction. Because of the one-way clutch on which driven wheel 52 is mounted, wheel 52 does not rotate in the clockwise direction. Because the beltloop material is held between grooved idler wheel 50 and knurled driven wheel 52, the rotation of knurled wheel 52 causes the beltloop material to advance to the left each time piston rod 62 is retracted into cylinder 64.
In practice, cylinder 64 is a double-acting pneumatic cylinder whose timed operation is under control of a programmable control system that may be any one of a plurality of known programmable controllers. I have used a controller known as a Melsec F2-60M, Model F2-60 M2-U, sold by Mitsubishi Electric Corporation, Tokyo, Japan.
The programming and the operation of the control system are conventional and known in the art. Accordingly, because the control system, per se, is not the subject of my invention, I will not describe it in detail except to mention that the steps of the program are usually performed in response to signals that are produced from position sensors or "pick off" devices of known types, such as Hall effect devices and permanent magnets, on relatively moving parts, or reed switches and permanent magnets on relatively moving parts. Also, some programmed steps are produced after a timed delay following a position sensor output signal. Suitable support means may be required to position the position sensor means at desired locations on and/or adjacent the moving parts.
As best seen in FIG. 2, another leaf spring 70 has its right end secured to the back of the forked end of swing arm 22. The spring extends to the left through the reduced diameter portion of grooved wheel 50 and terminates in a downwardly depending foot portion 72 that resiliently contacts the top surface of the beltloop material to hold it flat and straight as the material approaches the cutoff knife blade 78.
Referring now to FIGS. 4 and 5, knife blade 78 is attached to mounting bar 80a by means of screws so that it may be removed for sharpening of replacement. Mounting bar 80a includes a thick, apertured end 80b that receives the end of knife shaft 82. Mounting bar 80a and its end 80b are secured to and rotate with knife shaft 82 by means of set screw 84. Knife shaft 82 is rotatably supported in bushing block 86 that is adjacent the end 80b of the knife mounting block, and the opposite end 88 of knife shaft 82 is rotatably received in a bushing block 90. Bushing block 86 is secured to the base plate 16 of the knife assembly. Collar 92 is secured intermediate the ends of knife shaft 82 by means of set screw 94. Helical spring 96 is coaxial about knife shaft 82 and is retained in compression between collar 92 and the end face of bushing block 86. This arrangement of helical spring 96 urges knife shaft 82 toward the rear of the feed and cutoff subassembly A to bring knife blade 78 into close shearing relationship with the shearing edge 100, FIG. 2.
A pinion gear 104 is secured to knife shaft 82 by means of set screw 106 that is in the hub of the gear. Pinion gear 104 is in engagement with rack 108, FIG. 4, which is attached to the end of a piston shaft 112 that is reciprocated up and down by means of the large flat pneumatic cylinder 114. The actuation of cylinder 114 will raise and lower rack 108 to cause rotation of pinion 104 and knife shaft 82. This motion causes knife blade 78 to come down across the shearing edge 100, FIG. 2, to cut a piece of beltloop material 12 that is extending beyond the shearing edge. Pneumatic cylinder 114 is actuated in its programmed sequence by the programmed controller mentioned above.
As will be explained in more detail below, during the operation of the apparatus of this invention, knife blade 78 cuts beltloop material 12 so that the material's end is at the shearing edge 100, FIG. 2. Cylinder 64 is actuated to cause driven knurled wheel 52 to rotate a given amount to cause a length of approximately 3/8 inch of beltloop material to advance beyond the shearing edge 100. A beltloop puller mechanism B that includes a pair of puller jaws 120,122, FIGS. 1,2, and 6, clamp onto the free end of the beltloop material and pull out a desired length of the material from the feed and cutoff subassembly A. The puller subassembly B includes a mounting base 124 to which upstanding end plates 126, 128 are secured. A pair of spaced slide rails 132, 134 are mounted between the end plates, and a slide assembly comprised of horizontal and vertical blocks 136, 138, respectively, are mounted on the slide rails by means of suitable bushings. A pneumatic cylinder 140 having a piston rod 141 is mounted between end block 128 and vertical block 138. The end of piston rod 141 is secured to block 138 by any suitable means that may include a nut 142, so that when the piston rod is translated horizontally in and out of the cylinder 140 the slide assembly comprised of blocks 136 and 138 is translated back and forth on slide rails 132, 134.
A puller bar 150 is secured to slide block 138 by suitable means, and puller jaws 120, 122 are attached to the outer end of bar 15. As illustrated in FIG. 6, the left end of puller bar 150 has a central bore therein which includes a pneumatic cylinder having an air input line 154 connected at its right end. A piston 156 is disposed in cylinder 152 and is urged toward the right, or inner, end of the cylinder by a compression spring 160. An end cap 162 closes the end of bore 152.
Upper and lower puller jaws 120, 122 are pivotally attached to puller bar 150 by means of a pivot pin 166 that passes through respective apertures in the lever arms of the jaws and through apertures in opposite side walls of the puller bar. A push rod 170 is carried by piston 156 and extends through side slots 172 on both sides of the cylinder body. The opposite ends of push rod 170 are received in respective oppositely inclined slots on the back parts of the lever arms of the two jaws 120, 122. Spring 160 urges piston 156 toward the right so that push rod 170 normally is at the far end of inclined slot 174 in lower jaw 122. This causes lower jaw 122 to pivot about pivot pin 166 in the counterclockwise direction in FIG. 6 to hold jaw 122 in its open position. The slot in upper jaw 120 corresponding to slot 174 is inclined transversly to slot 174 so that push rod 170 causes top jaw 120 to rotate in the clockwise direction when piston 156 and push rod 170 are at their far right positions.
When air is forced into the right end of cylinder 152, piston 156 is translated to the left in FIG. 6, and push rod 170 moves toward the front of inclined slot 174 in the lever arm of bottom jaw 122. This causes bottom jaw 122 to rotate in the clockwise direction about pivot pin 166 to close bottom jaw 122 on the bottom of a beltloop. Because the slot in the lever arm of top jaw 120 is inclined oppositely to slot 174, top jaw 120 pivots in the counterclockwise direction to close toward the lower jaw 122. When increased air pressure on the right side of piston 156 is terminated, spring 160 returns piston 156 to the right end of cylinder 152 and push rod 70 moves to the back ends of the respective slots, and the two jaws open in opposite directions.
In the operation of the puller subassembly B, pneumatic cylinder 140 is actuated at the proper time by the above-mentioned programmed controller and the slide assembly comprised of slide blocks 136, 138 is moved to the right in FIG. 1 to place the open jaws 120,122 over the free end of a piece of beltloop material 12 that is extending beyond the shearing edge 100. Piston 156 in the end of puller rod 150 then is translated toward the outer end of the cylinder to cause jaws 120,122 to close and grip the free end of the beltloop material. With jaws 120, 122 clamped to the free end of the beltloop material 12, cylinder 140 in the puller subassembly is actuated by the control system to retract piston rod 141 within the cylinder and thereby pull the closed jaws 120, 122 away from the feeder and cutoff subassembly A a predetermined distance so that a desired length of beltloop material is beyond knife blade 78.
With the predetermined length of beltloop material 12 pulled out by puller jaws 120, 122, transfer clamp subassembly C is actuated to grasp the beltloop material in the following manner. The transfer clamps subassembly C is illustrated in FIGS. 2, 3 and 7 and includes a pneumatic, double acting horizontal slide 180 that is slidably mounted on rods 182, 184 that are fixed at their opposite ends to end bars 186, 188. End bars 186 and 188 are secured to base plate 10. Air hoses 190, 192 couple double-acting slide 180 to a source of air pressure that is under control of the programmed control system. A base block 196 is secured to the top surface of slide block 180 and a pair of spaced, vertical slide rods 200, 202 is secured to base block 196. A vertical slide 208 having a pair of spaced bushings therein is adapted to slide up and down on slide rods 200, 202. A pneumatic, double acting cylinder 212 is mounted on horizontal slide 180 and has a piston rod 214 that moves vertically when the cylinder is actuated. An angled bracket 218 is secured to the top of piston rod 214 and is secured along its vertical side to vertical slide 208 so that the vertical slide moves up and down with the movement of the piston rod 214.
As illustrated in FIG. 7, a pair of angled clamp mounts 220, 222 are secured by bolts, not illustrated, in spaced relationship on the top of vertical slide 208 and support respective transfer clamps 226 and 228. The exploded view of transfer clamp 228 shows that clamp mount 222 has a pair of spaced posts 230 and 232 that pivotally supports a clamp actuator 234 which includes therein a pair of spaced, independently actuated pistons 240 and 242. A bottom clamp finger 246 is secured, as by screws, to threaded holes 248, 250 in the tops of posts 230 and 232 of clamp mount 222. A top clamp finger 254 is secured to a post 256 on clamp actuator 234. It is seen that clamp actuator 234 extends through aperture 260 in bottom clamp finger 246 and that clamp actuator 234, and thus top clamp finger 254, is pivotable with respect to clamp mount 222.
When bottom piston 242 in clamp actuator 234 is actuated by the control system it moves downwardly against the adjacent surface of clamp mount 222 and raises the back portion of clamp actuator 234 so that the clamp actuator pivots about the pivot pin between posts 230 and 232. This pivoting action causes the outer end of top clamp finger 254 to move downwardly against the outer end of lower clamp finger 246, and thus closes the clamp. When top piston 240 in clamp actuator 234 is actuated by the control system it moves upwardly against the bottom surface of stationary bottom clamp finger 246 and causes clamp actuator 234 to pivot in the clockwise direction around its pivot pin. This causes top clamp finger 254 to move away from the bottom clamp finger 246, and thus opens the clamp.
During a complete cycle of operation of the apparatus of this invention the transfer clamps 226 and 228 move to four different positions. The first position is illustrated in full lines in FIG. 3. The second, a raised position, is illustrated in broken lines in FIG. 3. The third position is the raised position, but horizontal slide 180 is at it's rearmost position designated generally by "T". The fourth position is with the horizontal slide 180 in its rearmost position and the vertical slide 208 in its bottom position.
The loop former subassemblies D of the apparatus of this invention is illustrated in FIGS. 1, 2, and 8. As seen in FIGS. 1 and 2, there are a pair of loop formers 280,282 above and to the sides of transfer clamps 226,228. Each loop former subassembly is supported on a respective angled bracket which is comprised of a vertical plates 290, 292 secured to base plate 10 and horizontal plates 296, 298 secured to respective ones of the vertical plates. The loop formers on the two sides includes two pairs of spring loaded open jaws 284a, 284b and 286a, 286b. Each of the top jaws 284a, 286a is secured to a respective support arm 284c, 286c and each bottom jaw is pivotally joined to its respective support arm. Springs 284d, 286d resiliently bias the open bottom jaws toward the top jaws. It is to be noted that the top and bottom jaws always are open a predetermined distance, as will become apparent from the description below.
Because the two loop formers are substantially identical, the remainder of the detailed description of their construction will refer only to the subassembly 280 illustrated in FIG. 8. Support arm 284c is secured to the underside of slide block 300 that freely slides on a pair of spaced, parallel slide rods 302 that are supported between end blocks 304,306. The end blocks are secured to the under side of horizontal plate 296. A vertical bracket 310 is secured to the forward edge of slide block 300 and passes through an aperture 312 in horizontal plate 296. Two back-to-back pneumatic cylinders 322 and 323 have their respective piston rods 320,321 extending from opposite ends of the two cylinders. That is, piston rod 320 of cylinder 322 extends outwardly to the left in FIG. 8 and is secured to vertical bracket 310 that extends upwardly through aperture 312. Piston rod 321 of cylinder 323 extends to the right in FIG. 8 and is secured to end plate 324 that is in turn secured to horizontal plate 296. In its normal position, pneumatic cylinder 323 has its piston rod 321 withdrawn within the cylinder so that the right end of the cylinder is closely adjacent end plate 324. In its actuated condition, piston rod 321 is extended approximately one-quarter inch. This pushes the back-to-back cylinders 323, 320 to the left in FIG. 8, and pushes vertical block 310, slide block 300, support arm 284c, and loop former jaws 284a, 284b to the left one-fourth inch.
In its normal position, piston rod 320 of pneumatic cylinder 322 is extended as illustrated in FIGS. 2 and 8. In its actuated position, piston rod 320 is withdrawn approximately one inch within cylinder 322 to move vertical block 310, and thus support arm 284c and loop former jaws 284a, 284b, one inch to the right in FIGS. 2 and 8. It thus is seen that the back-to-back cylinders 320,323 may operate in response to the programmed control system to move loop former jaws 284a, 284b between three different horizontal positions.
The actual operation of forming the folded-under loops on the ends of the cut piece of beltloop material will be described in detail below in the explanation of the operation of the apparatus which appears below. For the present discussion, it is assumed that a cut length of beltloop material with loops on each end is held between the two spaced loop formers 280,282, substantially as illustrated in FIG. 16. This beltloop with the ends folded under is clamped and fed to a sewing station by a pair of feeder clamps 342, 344 that are illustrated in FIGS. 1-3, and 9. Because the two feeder clamps are identical, only one will be described. As best seen in FIG. 9, a feeder clamp is comprised of a bottom clamp finger 346 that is secured to the underside of a clamp body 348, and a top clamp finger 352 that is secured to a pivotable clamp actuator 354. Clamp actuator 354 pivots on pivot pin 356 that extends between spaced, parallel posts 358 on clamp body 348. A cover plate 362 is secured to clamp actuator to pivot it with respect to clamp body 348. A cover plate 362 is secured to clamp body 348 and cooperates with pistons 364 and 366 in clamp actuator 354 to pivot the actuator with respect to clamp body 348, thereby to open and close top clamp finger 352 relative to bottom clamp finger 346. This arrangement and operation is substantially the same as that described above in connection with transfer clamps 226, 228 so will not be further described.
Clamp bodies 348 of feeder clamps 342, 344 are attached to a horizontally extending mounting bar 370 that is secured to the ends of a pair of slide rods 372, 374. As seen in FIG. 9, the right ends of slide rods 372,374 are secured to a rigid yoke member 376. The slide rods slide in respective bushings in U-shaped horizontal slide block 380. Horizontal mounting bar 370 is attached to piston rod 384a of pneumatic double-acting cylinder 384. As illustrated, slide block 380 is provided with a clearance hole to permit piston rod 384a to freely slide therethrough. Cylinder 384 is secured between a rear vertical bracket 386 and the transverse portion 380a of slide block 380. Bracket 386 is secured to base plate 10.
A second pneumatic double-acting cylinder 390 is attached to the transverse portion 380a of slide block 380, and its piston rod 390a extends freely through the slide block and terminates in a pusher pad 392 that is adapted to contact the back side of horizontal mounting bar 370. A third double-acting pneumatic cylinder 394 is attached to a transverse strut 396 which is secured to the rear portion of slide block 380. The piston rod 394a extends to the right and its free end, when extended as illustrated in FIG. 9, is positioned to contact the yoke member 376 when slide rods 372, 374 move to the left a predetermined distance which is less than the full stroke of piston rod 384a.
Horizontal slide block 380 and all the described apparatus associated therewith is adapted to be moved up and down between three different heights by means of a pneumatically actuated, bilateral acting, pneumatic actuator block 400. Air ports 400a and a pair of pistons associated therewith actuate a pair of piston rods 402 to raise and lower horizontal slide block 380 between extreme top and bottom positions. A second pair of air ports 400b associated with a second pair of pistons in actuator block 400 independently actuate a second pair of piston rods 404 to move horizontal slide block 380 approximately one-quarter inch.
As illustrated, both pairs of piston rods 402, 404 are attached at their top ends to a mounting bracket 410 which is secured to horizontal slide block 380. The bottom ends of the piston rods are attached to bracket 412 which is secured to the base plate 10.
With the arrangement just described, feeder clamps 342 and 344 can be moved between four horizontal positions and between three vertical positions. All of these motions are controlled by the programmable controller.
Explanation of Operation
Having described the construction of the apparatus of this invention, an explanation of its operation now will be given in connection of the simplified illustrations of FIGS. 10-22. In the initial condition illustrated in FIG. 10, it is assumed that beltloop material 12 is at the shearing edge 100 and that knife blade 78 is in its raised position. Piston rod 141 associated with puller jaws 120, 122 is withdrawn to the left so that vertical plate 138 and puller arm 150 are at their extreme withdrawn positions. In this initial condition, the transfer and feeder clamps all are closed.
In FIG. 11, cylinder 64 is actuated to retract piston rod 62 and cause crank arm 58 to rotate in the counterclockwise direction a sufficient amount to advance beltloop material 12 approximately 3/8 inch beyond the end of shearing edge 100. Next, piston rod 141 is advanced toward the right to cause open puller jaws 120, 122 to be positioned above and below the free end of beltloop material 12. Jaws 120, 122 then close on the end of the beltloop material and piston rod 141 is retracted a predetermined distance by its pneumatic cylinder 140 so that a predetermined length of the continuous beltloop material is drawn beyond the shearing edge 100, as illustrated in FIG. 12. The one-way clutches on idler wheel 30 and driven wheel 52 permit those wheels to rotate while the beltloop material is drawn out by puller jaws 120, 122.
At this point in the operating cycle, transfer clamps 226 and 228 of FIG. 7 are at their lower and rearmost positions. The horizontal slide 180 of the transfer clamps subassembly of FIG. 7 is actuated to move the subassembly forward so that the top and bottom fingers of the open transfer clamps 226,228 extend over and under beltloop material 12. When appropriate position sensors determine that transfer clamps 226, 228 are at their proper horizontal positions, a control signal is generated to cause the fingers of the clamps to clamp onto the beltloop material 12. Puller jaws 120, 122 are caused to open, and after a delay of 2/10 second, the large cylinder 114, FIG. 4, is actuated to raise rack 108 and rotate pinion 104 to thereby cause knife blade 78 to swing downwardly and cut beltloop material 12 at shearing edge 100, FIG. 13.
Vertical cylinder 212 of the transfer subassembly C, FIG. 7, next is actuated to raise the transfer clamps 226, 228 from their lowest position, illustrated in broken lines in FIG. 14, to their highest position which is illustrated in solid lines in FIG. 14. It is seen in FIG. 14 that as the cut beltloop approaches its upper position the free ends contact the lower jaws 284b, 286b of the two loop folders 280, 282 that are adjacent and at substantially the same height as the transfer clamps. This contact causes the free ends of the beltloop to bend downwardly.
In the positions of the loop folders illustrated in FIG. 13, piston rod 321, FIG. 8, is withdrawn within cylinder 321 and piston rod 320 of cylinder 322 is extended one inch from its withdrawn position.
The next step is illustrated in FIG. 15 and involves both loop folders moving inwardly approximately one quarter inch so that the respective top and bottom jaws of the formers move over the outer sides of bottom fingers 246 of the transfer clamps. In so moving, the lower jaws 284b, 286b of the loop formers cause the free ends of the beltloop to fold under their respective bottom fingers 246. It is noted that the outer tips of the top and bottom jaws of the loop formers are inclined toward the beltloop so that they hold the folded beltloop ends substantially along respective line contacts. As described above, each pair of jaws of the loop formers are spring biased against further opening so that they will resiliently clamp the looped ends of the beltloop therebetween.
When the two loop folders reach their innermost positions illustrated in FIG. 15, a signal is generated by a suitable position sensor. The control system responds to this signal to cause the top fingers 254 of the transfer clamps to pivot upwardly and release the beltloop. After a time delay of approximately 1/10 second, the horizontal slide block 180 of the transfer clamp subassembly, FIGS. 3 and 7, is actuated to move the transfer clamps to the rear so that they move from their forward position illustrated in broken lines in FIG. 3 to the rear position represented generally by the location T. Vertically acting cylinder 212 next is actuated to drop the transfer clamps to their lowest positions. They now have completed a cycle of movement. The beltloop with the folded-under ends now is held solely by the loop formers, as illustrated in FIG. 16.
The vertical slide actuator 400 of the feeder subassembly of FIG. 9 next is actuated to lower the feeder clamps 342, 344 from their uppermost positions illustrated by broken lines in FIG. 17 to their lowermost positions. Feeder clamps 342, 344 advance horizontally from their rearmost positions to a position where the lower fingers 346 of the clamps are below the folded ends of the beltloop and the upper fingers 352 are above the beltloops, as illustrated in the solid lines in FIG. 17. It is seen that the lower fingers of the feeder clamps are shaped to accommodate the folded-under ends of the beltloop.
The feeder clamps are now in the second one of their four horizontal positions. Reference will be made to FIG. 9 for an explanation of how this position was reached from their rearmost, or most retracted position. Cylinder 390 is actuated so that it extends its piston rod 390a in the forward direction. Pad 392 on piston rod 390a engages against the rear of mounting bar 370 and pushes it and feeder clamps 342, 344 outwardly a predetermined distance so that the fingers of the feeder clamps can engage the beltloop in the manner illustrated in FIG. 17.
When the feeder clamp assembly E reaches this second horizontal position, a position sensor is activated and upper fingers 352 of the clamps are pivoted downwardly to securely clamp the folded-under ends of the beltloop between the top and bottom fingers of the feeder clamp. Two-tenths of a second later, the pneumatic cylinders 322 of the loop folder subassemblies 280, 280 are actuated and the folder jaws are retracted one inch away from the clamped ends of the beltloop, as illustrated in FIG. 18. The loop formers now are out of the way in anticipation of the forward movement of the feeder clamps.
At this same time in the cycle of operation, pneumatic cylinder 140 of the puller subassembly is actuated to extend puller jaws 120, 122 to the right in FIGS. 1 and 2. And, pneumatic cylinder 64 in the beltloop feeder subassembly is actuated to feed 3/8 inch of beltloop material beyond shearing edge 100, thereby to commence another operation of pulling out from the continuous supply of beltloop material another predetermined length of material. The described operations of actuating the transfer clamps so that they clamp the pulled-out length of beltloop material, and cutting the beltloop at shearing edge 100, continue in sequence on the next length of beltloop material while the feeder clamps are clamping onto the first described beltloop.
Returning to feeder clamps 342, 344 that have the first described beltloop clamped therein, the vertical actuator block 400, FIG. 9, is actuated to raise the feeder clamps to their highest positions. Both cylinders 384 and 394 are actuated to extend their respective piston rods. Piston rod 384a of cylinder 384 moves slide rods 372, 374 and yoke member 376 forward until yoke 376 contacts the end of extended piston rod 394a. This stops the forward motion of slide rods 372, 374 and yoke 376 at a position immediately in front of the sewing station where the beltloop will be stitched to the trouser waistband. This "loop ready position" is illustrated in FIG. 19. The apparatus now rests at this position until the operator actuates a button or foot switch to resume the operation and commence the stitching.
The sewing machine that is partially illustrated in FIG. 19 preferably is a twin needle machine of the type described in U.S. patent application Ser. No. 909,314, filed Sept. 19, 1986 in the name of J. Off, and which is incorporated herein by reference. As illustrated in FIG. 19, presser feet 440 and needles 442 are in their elevated positions when the feeder clamps 342, 344 are in their "loop ready positions". The upper and lower arms 446 and 448 of the sewing machine are only partially shown in FIG. 19. In this embodiment of the invention, presser feet 440 are somewhat U-shaped, i.e., they are open at their front ends that face the feeder clamps.
Assuming that the operator now presses a foot switch to continue the operation, pneumatic cylinder 394 is actuated to withdraw its piston rod 394a into the cylinder, and cylinder 384 still is actuated so that its piston rod 384a extends farther outwardly to move mounting block 370 and feeder clamps 342, 344 into the presser feet 440, see FIG. 20. It is seen that the top fingers 352 advance into the open front ends of the presser feet to position the beltloop 12 under needles 442 ready for stitching to the waistband of the trousers. The folded-under ends of the beltloop are directly under the two needles of the sewing machine. For simplicity of illustration, the trousers are not illustrated in the drawings of FIGS. 19-22.
When the feeder clamps are fully advanced under the raised needles, i.e., at the sewing station, a signal is produced and the control system actuates the second set of piston rods 404 associated with ports 400b of vertical actuator 400 to cause feeder clamps 342 and 344 to be lowered approximately 1/4 inch onto the top surface of the lower arm of the sewing machine. Simultaneously, a signal is coupled to the automatic sewing machine to cause presser feet 440 to be lowered onto the beltloop to hold it firmly in position. After a delay of approximately 1/10 second, a signal is produced to cause the top fingers 352 of feeder clamps 342, 344 to open, see FIG. 21.
At the time that the operator actuated the foot switch to continue the operation on the first beltloop, the transfer clamps 226, 228 having the second length of beltloop material clamped therein is raised up to the loop folders 280,280 and the ends are folded under in the manner described in connection with FIGS. 13-16.
Resuming the explanation of the operation on the first beltloop at the sewing station, the control system next produces a signal to start the needles 442 reciprocating to form desires stitches at the folded-under ends of the beltloops. Simultaneously, cylinder 384 of the feeder clamp subassembly is actuated to retract piston rod 384a and cause feeder clamps 342, 344 to withdraw to their rearmost positions. Vertical slide block 400 immediately is actuated to lower the feeder clamp assembly to its lowest position. The feeder clamps then are moved forward to engage the second described beltloop from the transfer clamps 226, 228 and the operation continues as described above.
It is seen that the apparatus actually is operating on two beltloops at the same time and little time is lost between presenting successive beltloops to the sewing station.
From the above description it is seen that the apparatus forms beltloop with short folded-under ends, and that additional handling and additional apparatus are not required. All of the deficiencies noted in the prior art are overcome. The machinery is fast in operation and presents folded beltloops as fast as the operator can operate the machinery.
In its broader aspects, this invention is not limited to the specific embodiment illustrated and described. Various changes and modifications may be made without departing from the inventive principles herein disclosed. | A method and apparatus for forming belt loops and transferring the formed loop to a sewing station where the loop may be stitched to the waistband of a pair of trousers. The invention is particularly useful in sewing belt loops onto the waistbands of trousers of the blue jeans type. | 3 |
This is a division of application Ser. No. 247,280 filed Mar. 25, 1981.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a tire manufacturing mold and a manufacturing method therefore, and more particularly to a tire manufacturing mold and a manufacturing method, based on discharge machining, in which a contour surface of the mold consisting of a predetermined curved surface corresponding to the outer circumferential surface of a tire being molded and bone portions and blade portions, both protruding on the contour surface, are integrally formed by discharge machining.
2. Description of the Prior Art
In manufacturing a tire manufacturing mold, plate-like protrusions (hereinafter referred to as blades) corresponding to grooves as commonly found of the tread surface of a tire must be formed on the tire mold. It is extremely difficult, however, to machine such blades on a tire metal mold with cutting operation, discharge machining, etc. in such a fashion that the blades are integrally formed with the mold proper. Heretofore, therefore, the following method has been commonly used. That is,
(i) Molds of the same size and shape as the segments obtained by radially dividing a tire being molded are prepared, using gypsum, for example, on the assumption that there exist no grooves on the tire
(ii) Metal pieces, for example, having the same cross-sectional shape as the grooves and a predetermined height are fitted, using adhesive and other appropriate means, on the gypsum models at positions corresponding to those of the grooves on the tire. Using these gypsum models as matrices, n pieces of their reversed molds are prepared with resin, etc.
(iii) Blades, made of stainless steel, etc., of a predetermined height are inserted into all the grooves formed on the reversed molds by the metal pieces. The predetermined height of the blade is such that the height of the blade excluding the portion being inserted into the groove is equal to the height of the blade being provided on the tire mold.
(iv) Gypsum is poured into the reversed molds with the blades and allowed to cure. Thus, gypsum casting molds are obtained by removing the reversed molds. At this time, the blades inserted in the reversed molds are moved to the casting molds with the portion thereof previously inserted in the reversed mold exposed on the casting mold.
(v) The gypsum casting molds thus formed are arranged in a ring shape and used as a matrix for molding the desired tire manufacturing mold with aluminum precision molding, for example.
With this method, the portion of the blade previously exposed on the casting mold is embedded in the tire manufacturing mold with the portion thereof previously embedded in the gypsum casting mold exposed on the tire manufacturing mold.
Another method of providing blades on a tire manufacturing mold is as follows.
Tire manufacturing metal molds without blade portions are first manufactured. And then, grooves corresponding to the cross-sectional shape of the blades are formed on the corresponding positions of the molds by manual metalworking or discharge machining, and prefabricated blades are embedded in these grooves.
These conventional methods, as described above, involve complex manufacturing processes, resulting in increased manufacturing costs. In addition, embedded blades are very likely to become loosened, coming off in some cases.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a tire manufacturing mold manufactured by electrodischarge machining in such a manner that a contour surface, bone portions and blade portions corresponding to the outer circumferential surface of the tire being molded are integrally formed, and the manufacturing method thereof.
It is another object of this invention to provide a tire manufacturing mold manufactured by electrodischarge machining, which can contribute to reduction of manufacturing costs through labor saving in the manufacture of metal molds, and the manufacturing method thereof.
It is still another object of this invention to provide a tire manufacturing mold in which blade portions are integrally formed with the mold proper by electrodischarge machining so as to prevent the blade portions from coming off and thereby to increase the mechanical strength of the mold.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional side elevation of a tire manufacturing mold embodying this invention.
FIG. 2 is a partially enlarged cross-section of the lower half of the mold shown in FIG. 1.
FIG. 3 is a developed plan view taken substantially along the line A--A' in FIG. 2.
FIGS. 4A and 4B are a front view and side view, respectively, of an example of the electrodischarge machining equipment for use in this invention.
FIGS. 5A through 5C are sectional diagrams which are useful in explaining the first-stage discharge machining in the manufacturing process of the tire manufacturing mold of this invention.
FIGS. 6A through 6C are sectional diagrams which are useful in explaining the second-stage electrodischarge machining in the manufacturing process of this invention.
DETAILED DESCRIPTION OF THE INVENTION
An example of the tire manufacturing mold being manufactured by this invention is shown in FIGS. 1 through 3.
In the figures, reference numeral 1 refers to an upper-half mold; 2 to a lower-half mold; 3 to a contour surface corresponding to the tread surface of the tire being molded; 4 to a shoulder portion; 5 through 9 to relatively broad bone portions; 10 and 11 to relatively narrow blade portions; PL to a parting line at which the upper-half mold and the lower-half mold are matched together; and CL to a center line corresponding to the center line of the tread surface of the tire being molded.
Next, an example of the electrodischarge machining equipment used for the manufacture of the tire manufacturing mold of this invention will be described, referring to FIGS. 4A and 4B.
In FIGS. 4A and 4B, numeral 13 refers to a work; 14 to a first machining head for feeding a machining electrode in the direction shown by arrow H in the figure; 14' to a pulse motor of the first machining head 14; 15 to a spindle of the first machining head 14; 16 to a second maching head for feeding a machining head in the direction shown by arrow h in the figure; 16' to a pulse motor of the second machining head 16; 17 to a machining electrode mounting jig; 18 to a machining electrode; 19 to a head support for supporting the first machining head 14; 20 to a head rotating drive unit for rotating the head support 19, together with the first machining head 14 in the direction shown by arrow α in the figure; 21 to a carriage which is supported by a column 23 and can be lifted and lowered by a lead screw 22 in the direction shown by arrow Z in the figure; 24 to a electrolyte tank; 25 to a machining table on which the work 13 is placed; 26 to a table rotating drive unit for rotating (servo-driving) the machining table 25 in the direction shown by arrow θ in the figure by means of, for example a pulse motor or hydraulicdrive unit; 27 to a first table for moving the machining table 25, together with table rotating drive unit 26, in the direction shown by arrow X in the figure; 28 to a second table for moving the first table 27 in the direction shown by arrow Y in the figure; and 29 to a bed, respectively.
In FIGS. 4A and 4B illustrating an example of the electrodischarge machining equipment for use in this invention, the first machining head 14 drives the spindle 15 in the direction shown by arrow H in the figure by means of the pulse motor 14'. At the tip of the spindle 15 is fixed the second machining head 16, which drives the machining electrode 18 in the direction shown by arrow h in the figure by the pulse motor 16' via the electrode mounting jig 17. As the operation of the second machining head 16 will be described later, the description here is based on the assumption that the second machining head is in a still state. The movement of the spindle 15 in the direction H by the pulse motor 14' of the first machining head 14 is controlled in such a manner that the gap between the machining electrode 18 and the work 13 can be maintained constant with the progress of machining in accordance with predetermined machining conditions such as electrode voltage, discharge current, etc. (hereinafter referred to as automatic servo-drive). In place of the pulse motors 14' and 16' for driving the first and second machining heads 14 and 16, a hydraulic servo drive unit and other appropriate automatic servo drive units may be used.
The electrodischarge machining equipment for use in this invention, as shown in FIGS. 4A and 4B, is capable of setting the angle of the first machining head 14 in the direction H, that is, the angle of the machining electrode 18 in the automatic control feed direction with respect to the machining table 25 at a desired angle through the rotation of the head support 19 in the direction α, the lifting and lowering of the carriage 21 in the direction Z, and the rotation in the direction θ and the movement in the directions X and Y of the machining table 25. At the same time, the electrodischarge machining equipment is also capable of setting the machining position of the electrode 18 for discharge machining the work 13 at any desired position. The detailed description of the positioning method of the work 13 and the electrode 18, which has already been proposed by the present inventors in their U.S. Pat. No. 4,409,457 granted Oct. 11, 1983, is omitted here.
Next, this invention will be described, with particular reference to the lower-half mold 2 of the tire manufacturing mold shown in FIGS. 1 through 3.
In general, a tire has on the tread surface thereof a plurality of grooves formed essentially vertically to the tread surface. Consequently, on a metal mold for molding such a tire, for example, the lower-half mold 2 as shown in FIG. 2, is provided with the bone portions 6 and 8 and the blade portions 10 and 11 which protrude virtually vertically to the contour surface thereof, corresponding to the aforementioned grooves.
In discharge machining a mold such as the lower-half mold 2 shown in FIG. 2 the contour surface of which has a plurality of projections formed vertically to the contour surface, the feeding of a machining electrode (not shown) in any direction, for example, in any of the directions shown by arrows a, b and c in FIG. 2 would result in unwanted metal removal on any of the bone portions 6 and 8 and the blade portions 10 and 11.
To overcome such unwanted metal removal, the feeding direction of the machining electrode is made changeable between the direction coinciding with the protruding direction of the bone portion 6 and the blade portion 10 and the direction b coinciding with the protruding direction of the bone portion 8 and the blade portion 11. Thus, the first-stage discharge machining is performed by using different machining electrodes having such profiles as to prevent the aforementioned unwanted metal removal for each discharge machining in the electrode feeding directions a and b. The first-stage discharge machining will be described in the following, referring to FIGS. 5A through 5C. In the figures, numerals 2, 3, 6 through 11, 13 and 17 correspond with like numerals in FIGS. 1 through 4. Numerals 18a and 18b refer to first-stage machining electrodes; 3a and 3b to electrode contour surfaces; 6a through 11a to electrode recesses formed on the machining surface of the first-stage machining electrode 18a; and 6b through 11b to electrode recesses formed on the machining surface of the first-stage machining electrode 18b, respectively.
FIG. 5A is a cross-section of the final profile of the lower-half mold 2 to be manufactured in the invention.
FIG. 5B shows the first-stage machining electrode 18a used for machining in the direction a.
FIG. 5C shows the first-stage machining electrode 18b used for machining in the direction b. The first-stage machining electrode 18a for machining in the direction a has a profile corresponding to that of the lower-half mold shown in FIG. 5A, except for the electrode recesses 8a, 9a and 11a having such profiles as to prevent unwanted metal removal, as shown in FIG. 5b. Similarly, the first-stage machining electrode 18b for machining in the direction b has a profile corresponding to that of the lower-half mold 2 except for the electrode recesses 6b and 10b having such profiles as to prevent unwanted metal removal, as shown in FIG. 5C. The manufacturing method and device of the first-stage machining electrodes 18a and 18b have already proposed by the present inventors in the U.S. Pat. No. 4,409,457,so the detailed description of them is omitted here.
In the first-stage discharge machining according to this invention, the work 13 is first machined into a profile as shown by a dotted line in FIG. 5B by feeding the first-stage machining electrode 18a, positioned at a location shown in the figure, in the direction a. Then, using the first-stage machining electrode 18b in place of the electrode 18a, discharge machining is performed in the direction b to remove the portions shown by dotted line in FIG. 5C, which are left unmachined in the machining process shown in FIG. 5B, on the bone portions 8 and 9 and the blade portions 11. With this process, as shown in FIG. 5C, the desired profile of the lower-half mold 2 shown in FIG. 5A is obtained. The aforementioned first-stage discharge machining process can produce the desired profile of the lower-half mold 2 shown in FIG. 5A without causing unwanted metal removal on projections since the recesses 8a, 9a and 11a of the first-stage machining electrode 18a for use in the a-direction machining and the recesses 6b and 10b of the first-stage machining electrode 18b for use in the b-direction machining are formed into profiles shown in FIGS. 5B and 5C.
In practice, however, it is difficult to obtain the desired profile even with the aforementioned discharge machining process because there are some problems such as the wear of electrode caused with the progress of discharge machining and overcuts caused by secondary discharge by metal chips suspending in the discharge gap between the machining electrode and the work, as shown in FIGS. 6A and 6B. That is, when discharge machining (the first-stage discharge machining as described above) is carried out by feeding the first-stage machining electrode 18a having a profile corresponding to the desired profile as shown by a dotted line in the work 13 in FIG. 6A in the direction shown by arrow H in the figure by means of the first machining head 14 (shown in FIG. 4A), the work 13 will be formed into a profile shown in FIG. 6B. That is, the corners at which the contour surface 3 and each side surface of the bone portion 6 and the blade portion 10 intersect tend to be slightly rounded. This is caused by the fact that the edges of the mouths of the recesses 6a and 10a wear out and becomes rounded since the wear of an electrode occurs most pronouncedly at protrusions or corners on the electrode surface, as is generally known. Furthermore, the blade portion 10 tends to be tapered off toward the end thereof. This is due to the so-called overcut caused by secondary discharge by metal chips in the discharge gap.
It is necessary, therefore, to take into account this point in determining the profile of the recess 10a (shown in FIG. 6A) of the machining electrode 18a used for the first-stage machining. In this invention, the second-stage discharge machining as will be described in the following is performed on the work 13 shown in FIG. 6B after the first-stage discharge machining to obtain the desired profile as shown by a dotted line in FIG. 6A.
FIG. 6C is a diagram which is useful for explaining the second-stage discharge machining. In the figure, numeral 18c refers to a second-stage machining electrode; 6c and 10 c to electrode recesses provided for finish machining the bone portion 6 and the blade portion 10, respectively. The second-stage machining electrode 18c can be obtained by machining the side walls of the recesses 10a and 6a of the first-stage machining electrode 18a shown in FIG. 6B to widen the side walls of the recesses to such an extent that the rounded parts at the corners can be removed. The center lines of the recesses 10c and 6c thus formed are required to align with the center lines of the recesses 10a and 6 a of the first-stage machining electrode 18a. Needless to say, the second-stage machining electrode 18c is not limited to the one obtained by enlarging the widths of the recesses 10a and 6a of the first-stage machining electrode 18a, but may be a separately prepared electrode of the same profile.
By using the second-stage machining electrode 18c which is machined into such a profile to satisfy an equation (T-t=T'-t'), where T and T' are the widths of the openings of the recesses 10c and 6c, and t and t' are the finally finished widths of the blade portion 10 and the bone portion 6 shown by dotted lines in FIGS. 6A and 6C, the blade portion 10 and the bone portion 6 can be finished simultaneously with the second-stage discharge machining, which will be described later.
As shown in FIG. 6C, the second-stage discharge machining is performed in the following manner. The second-stage machining electrode 18c is first fed in the direction H by means of the first machining head 14, and then automatic servo driven by a distance (T-t)/2 in any one of the directions h by means of the second machining head 16 (shown in FIG. 4A). And then, the second-stage machining electrode 18c is automatic servo driven by a distance (T-t) in the other direction of the direction h to remove the metal left unmachined on the other side. As a result, the blade portion 10 and the bone portion 6 of the work 13 can be finished into the desired profile shown by a dotted line in FIG. 6A. The feeding distance of the second-stage machining electrode 18c in the directions H and h during the second-stage discharge machining can be set to a predetermined range by means of, for example, limit switches. That is, the automatic servo driving of the machining electrode 18c in the direction H is effected by the first machining head 14 until a limit switch (not shown) is actuated. When the limit switch is actuated, the feeding of the machining electrode 18c is stopped and the automatic servo driving of the electrode 18c in the direction h is started by the second machining head 16. If the electrode 18c and the work 13 are shortcircuited during the h-direction machining, the machining electrode 18c is immediately retreated by a predetermined distance in the opposite directions to the directions H and h. The retreat distance can also be set by presetting, for example the number of pulses fed to the machining heads 14 and 16. Needless to say, the machining electrode 18c, once retreated, is fed again in the direction H and then in the direction h to continue discharge machining. The retreating operation of the machining electrode 18c may be performed simultaneously in both directions H and h, or first in the direction h and then in the direction H.
In the foregoing, the second-stage discharge machining involving the feeding of the electrode in the direction h has been described. However, the blade portion 10 can be formed in a desired direction by simultaneously performing the automatic servo driving of the machining table 25 (shown in FIGS. 4A and 4B) in the direction θ, or the automatic servo driving of the second machining head 16 in the direction h and the automatic servo driving of the machining table 25 in the direction θ, and by controlling the speeds of the respective automatic servo driving operations in the directions h and θ at the same speed or different speeds, depending on the desired direction. Needless to say, the interlocking operation of the automatic servo driving operation in the direction H and the automatic servo driving operations in the directions h and θ is performed in the same manner as described, referring to FIGS. 6A through 6C.
As described above, this invention makes it possible to manufacture a tire manufacturing mold consisting of a single block in which the contour surface, bone portions and blade portions thereof are integrally formed by first-stage and second-stage discharge machining operations, thus contributing to labor saving and cost reduction in the manufacture of tire manufacturing molds and making it possible to increase the strength of the blade portions of the molds. | A method of making a mold which is utilized to manufacture a tire, the mold having a contour curved surface with broad bone portions and narrow blade portions extending therefrom, comprises a first machining stage utilizing a plurality of electrical discharge machining electrodes for approaching a workpiece used to make the mold, at different angles. Each of the electrodes used in the first machining stage are shaped to avoid the removal of excessive metal from the mold so that both the bone portions and the blade portions can extend normally from the contour curved surface. The method includes a second machining stage utilizing a further electrical discharge machining electrode which has recesses for receiving bone portions and blade portions formed by the first stage electrodes, and is movable laterally of the contour surface to form well-defined edges of the bone and blade portions. | 1 |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to U.S. Provisional Patent Application Ser. No. 60/938,741, filed May 18, 2007.
FIELD OF THE INVENTION
This invention relates in general to diamond earth-boring drill bits and, in particular, to a method of repairing a matrix body diamond bit.
BACKGROUND OF THE INVENTION
Rolling cone bits may have teeth machined from the steel bodies of the cones. Rolling cone bits may also have tungsten carbide inserts press-fit into mating holes in the cones. Hardfacing has been employed on the gage surfaces of both types of rolling cone bits, as well as on portions of steel bit bodies for many years to resist abrasive wear. Hardfacing is also applied to the machined teeth. However, hardfacing is not applied to tungsten carbide inserts.
The hardfacing typically comprises granules of tungsten carbide located within a steel alloy binder. One method of applying the hardfacing to rolling cone bits has been to use an oxy-acetylene torch to melt a hardfacing tube or rod onto the steel. The hardfacing rod is typically a steel tube containing a filler comprising tungsten carbide granules. The temperature to melt the tube and bond the hardfacing to the steel of the bit in a prior art method for rolling cone bits may be in excess of 1500° C.
Another type of bit, often called a diamond bit, has a cast metal-matrix body and polycrystalline diamond cutting elements attached to the body, rather than rolling cones. The metal-matrix material typically comprises tungsten carbide powder and a binder of a metal, such as copper. The metal-matrix material may also contain diamond grit in certain areas. Carbide elements may be attached to the body at various points to resist abrasive wear. Thermally stable polycrystalline (TSP) diamond members may also be attached to the body to resist abrasive wear, such as along the gage surface.
Hardfacing has normally not been applied to matrix body diamond bits. The high temperature for the prior art hardfacing process excessively melts the binder of the bit body metal-matrix material. Also, hardfacing has not typically been employed on diamond bit abrasive elements, such as cemented tungsten carbide inserts or tungsten carbide bricks. The high hardfacing temperature melts the binder of these members, which is typically cobalt, and also can cause the members to crack during cool down. In addition, if natural diamonds and/or diamond grit are employed in the metal-matrix of the body, the high temperatures of iron-based hardfacing causes the natural diamonds and synthetic diamonds to revert to carbon and form a carbon dioxide gas. The carbon dioxide gas creates a poor hardfacing layer. The high temperature for iron-based hardfacing has thus precluded its use as a hardfacing for a crown of a diamond bit.
Diamond bits have complex shapes and are very costly. Normally, after the bits are used in drilling, they become worn and require repair in order to be re-used. This repair might involve replacing any damaged or missing polycrystalline diamond cutting elements as well as replacing missing abrasive elements. The repair process can be time consuming and expensive.
SUMMARY
The present invention provides a method for repairing diamond earth-boring bits whereby hardfacing is applied on the gage surface of bit blades. The gage surface may contain natural diamonds, synthetic diamonds, thermally stable polycrystalline (TSP) diamonds, and/or carbide inserts. As the primary cutters on the bit blades are worn down during drilling, the gage surface of the bit blade is also worn down. A hardfacing is applied to the worn gage surfaces of the bit blade, thereby allowing the bit to drill deeper and longer without requiring replacement. Embodiments of the present invention include a method of applying hardfacing over carbide inserts set in the bit blades.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a diamond bit that is worn.
FIG. 2 is an enlarged perspective view of a portion of the diamond bit of FIG. 1 .
FIG. 3 is a perspective view of the diamond bit of FIG. 1 after repair to a gage area of the bit by hardfacing and grinding the hardfacing to the gage diameter.
FIG. 4 is a perspective view of the diamond bit of FIG. 1 , after some repairs have been done to the bit by hardfacing but before grinding.
FIG. 5 is an enlarged perspective view of a portion of the diamond bit of FIG. 1 illustrating a tungsten carbide insert on the bit that has been repaired by hardfacing.
FIG. 6 is a perspective view of another portion of the diamond bit of FIG. 1 , showing hardfacing applied to the blade for repair but before grinding.
FIG. 7 is a schematic sectional view of a portion of one of the gage areas of the diamond bit of FIG. 1 .
FIG. 8 is a perspective view of a diamond bit that is worn.
FIG. 9 is an enlarged perspective view of a portion of the diamond bit of FIG. 8 .
FIG. 10 is a perspective view of the diamond bit of FIG. 8 after repair to the gage area of the bit by hardfacing and grinding the hardfacing to the gage diameter.
FIG. 11 is a schematic sectional view of a portion of one of the gage areas of the diamond bit of FIG. 8 .
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1 and 2 , bit 11 is an earth-boring bit having a shank 13 , normally formed of steel. Shank 13 has a threaded stem 15 on its end for securing to the drill string (not shown). A crown 17 is formed on the end of shank 13 opposite stem 15 . Crown 17 is typically formed of a tungsten carbide metal-matrix material 18 .
Crown 17 has a plurality of blades 19 formed thereon. Blades 19 are preferably integrally formed with crown 17 and extend over and down the sides of crown 17 , forming a gage surface 20 . Gage surface 20 is an area located at the maximum diameter of each blade 19 and determines the diameter of the borehole being drilled. Junk slots 21 extend between each blade 19 . One or more nozzles (not shown) are located on the bottom of crown 17 between blades 19 for discharging drilling fluid. The drilling fluid, along with cuttings, flows through junk slots 21 and back up the annulus surrounding the drill string.
A number of polycrystalline diamond cutters (PDCs) 23 are mounted on the leading edge of each blade 19 . Some PDC elements 23 may be located on a portion of a blade 19 between the leading and trailing edges, behind those on the leading edges. In some bits, one or more of the PDC elements 23 will be located on the leading edges of part of gage surface 20 of each blade 19 . Each PDC element 23 comprises a disk of polycrystalline diamond bonded to a cylindrical cemented or sintered tungsten carbide base 25 ( FIG. 5 ), which, in turn, is brazed into a hole or receptacle 26 ( FIG. 4 ), which was provided in metal-matrix material 18 of blade 19 while crown 17 was being molded.
Bit 11 has a number of wear-resistant members mounted on it to resist wear of crown 17 . These wear-resistant members are harder and more resistant to abrasive wear than the metal-matrix material 18 of crown 17 . For example, the particular bit 11 shown has an optional cemented or sintered tungsten carbide insert 27 mounted to each blade 19 for resisting wear. Insert 27 is dome-shaped and is located approximately midway between the leading and trailing edges of each blade 19 above gage surface 20 . In this example, insert 27 is located directly rearward from one of the PDC elements 23 mounted at the leading edge of blade 19 .
In this embodiment, as shown in FIG. 2 , other wear-resistant members include natural diamonds 28 mounted on each gage surface 20 . Natural diamonds 28 are normally sufficiently large to be easily visible without magnification. Two vertical rows of natural diamonds 28 are shown on each gage surface 20 , but this arrangement can vary. The exposed faces of natural diamonds 28 are generally flush with the surface of metal-matrix material 18 .
Other abrasion-resistant members include carbide members 29 , typically called “bricks,” which are mounted on gage surface 20 of each blade 19 alongside the rows of natural diamonds 28 . Carbide bricks 29 are of cemented or sintered tungsten carbide, similar to the material used for carbide base 25 and tungsten carbide insert 27 , but are typically rectangular in shape. The exposed face of each brick 29 is generally flush with the surface of metal-matrix material 18 of gage surface 20 . FIG. 7 illustrates one of the carbide bricks 29 embedded within metal-matrix material 18 of crown 17 .
Also, FIG. 7 shows that metal-matrix material 18 in this example also contains diamond grit particles 30 , which are exaggerated in size. Diamond grit particles 30 comprise much smaller diamonds than natural diamonds 28 and are not readily visible without magnification. The individual particles of diamond grit 30 may be coated, and are embedded within metal-matrix material 18 at or near the surface.
In a different embodiment of bit 11 , as shown in FIGS. 8 and 9 , thermally stable polycrystalline (TSP) diamonds 39 are mounted on each gage surface 20 to resist wear of gage surface 20 . TSP diamonds 39 are typically larger than natural diamonds 28 ( FIG. 2 ) and are easily visible without magnification. Four offset vertical rows of TSP diamonds 39 are shown on each gage surface 20 , but this arrangement can vary. The exposed faces of TSP diamonds 39 are generally flush with the surface of metal-matrix material 18 .
Normally, crown 17 is formed in an infiltration process, which is a long cycle, high temperature, atmospheric pressure process. A graphite mold is formed in the shape of crown 17 . Shank 13 is supported by a fixture, and blanks are placed in the mold to define PDC element receptacles 26 ( FIG. 4 ). Tungsten carbide bricks 29 , natural diamonds 28 , TSP diamonds 39 , and tungsten carbide inserts 27 , if employed, are fixed at appropriate places in the mold. A matrix powder, typically tungsten carbide, is placed in the mold and around shank 13 . The powder may also contain diamond grit 30 in certain places. Binder particles, such as a copper alloy, are placed on an upper surface of the tungsten carbide powder within the graphite mold. The heat melts the binder, causing it to infiltrate down through the tungsten carbide powder, bonding the carbide powder, diamond grit 30 , natural diamonds 28 , TSP diamonds 39 , carbide bricks 29 and tungsten carbide inserts 27 . After removal from the furnace, the PDC elements 23 are subsequently brazed into receptacles 26 .
As shown in FIGS. 1 and 2 , after drilling a number of wells, some of the PDC elements 23 may be broken. In addition, some of the carbide bricks 29 may be cracked and broken. Tungsten carbide inserts 27 may be worn or broken. The leading and trailing edges of blades 19 may also become eroded. If the metal-matrix material 18 erodes too deeply, the carbide bases 25 cannot be reinstalled within receptacles 26 ( FIG. 4 ) and the bit 11 will have to be discarded. As shown in FIGS. 8 and 9 , after drilling a number of wells, the TSP gage surface 20 may be worn. If gage surface 20 continues to wear, further exposing TSP diamonds 39 , the bit 11 will eventually be discarded.
In the method comprised by this invention, hardfacing is employed on several areas of a bit that normally would not be feasible. The hardfacing is preferably a nickel or nickel alloy-based hardfacing. The nickel-based hardfacing melts at a much lower temperature than iron-based hardfacing, such as at a temperature less than 1200° C. This lower temperature is not as detrimental to metal-matrix material 18 , natural diamonds 28 , diamond grit 30 , TSP diamonds 39 , tungsten carbide bricks 29 , and tungsten carbide inserts 27 . The lower temperature does not excessively melt the binder from metal-matrix material 18 nor the binder from sintered tungsten carbide bricks 29 and inserts 27 .
One example of a type of suitable alloy is an alloy of nickel, boron, chromium and silicon in the following relative percentages by weight:
carbon .45% chromium 11.0% silicon 2.25% boron 2.5% iron 2.25% nickel balance
This alloy has a hardness of about 38-42 Rockwell C and a melting temperature of about 1100° C. The hard abrasive components may be the same as conventionally used on rolling cone bits with iron-based hardfacing. For example, the hardfacing may include monocrystalline tungsten carbide, sintered tungsten carbide, either crushed or spherical, and cast tungsten carbide, either crushed or spherical. The sizes of the particles and the quantity by weight of the particles to the binder may be the same as conventionally used in iron-based hardfacing, but are in no way limited to these parameters. Preferably, a rod is formed containing the nickel alloy mixed with the hard abrasive particles. The rod may be formed in different manners. One way is by liquid phase sintering of the nickel alloy and abrasive particles. Another way is by an extrusion process of the nickel alloy mixed with the abrasive particles, which results in the extruded product being rolled onto a spool. Alternatively, the nickel alloy could be made into a tube and the abrasive particles placed inside.
To repair bit 11 , normally a technician removes PDC elements 23 from their receptacles 26 before applying hardfacing so as to avoid the heat from damaging PDC elements 23 . They are removed conventionally by applying brazing temperature heat to soften the brazing metal. Once elements 23 are removed, the operator then uses an oxy-acetylene torch to apply the nickel-based hardfacing.
The technician will apply hardfacing to the worn gage surface 20 , as illustrated in FIGS. 4 and 10 and indicated by the numeral 31 . Gage hardfacing layer 31 may be applied completely over the cracked and broken carbide bricks 29 ( FIG. 3 ). As shown in FIGS. 7 and 11 , gage hardfacing layer 31 overlies carbide bricks 29 , metal-matrix material 18 , natural diamonds 28 , TSP diamonds 39 , and exposed diamond grit 30 . Gage hardfacing layer 31 may extend from the leading edge to the trailing edge of each blade 19 and may extend up to the closest PDC element 23 on each blade 19 (not shown). FIG. 5 shows hardfacing layer 35 applied to the exposed portions of tungsten carbide insert 27 ( FIG. 2 ).
After applying the hardfacing, the technician grinds gage surface hardfacing layer 31 to the original gage tolerances ( FIG. 3 ) and grinds the other hardfacing layers where needed. The operator then brazes PDC elements 23 into receptacles 26 ( FIG. 4 ). Tests indicate that the nickel-based hardfacing adheres well to metal-matrix material 18 and is wear resistant. | Hardfacing is applied on gage surfaces of bit blades, the leading and trailing edges of bit blades, and on carbide inserts. The gage surfaces contains natural diamonds, synthetic diamonds, thermally stable polycrystalline (TSP) diamonds and carbide inserts, and the hardfacing is applied over at least a portion of them. As primary cutters on the bit blades are worn down during drilling, the gage surfaces of the bit blades are also worn down. A hardfacing is applied to the worn gage surfaces of the bit blades, thereby allowing the drill bit to drill deeper and longer without requiring replacement. | 4 |
CROSS-REFERENCE OF RELATED APPLICATIONS
This application claims benefit under 35 U.S.C. §119 from Korean Patent Application No. 10-2005-0010636, filed on Feb. 4, 2005, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to a handoff system and method among heterogeneous networks, and to a mobile terminal and operation method thereof using the same, capable of performing seamless handoffs to the most appropriate network in aspect of resources of data-link layers and network layers.
2. Description of the Related Art
Recently, with performance improvements of mobile terminals such as handheld computers and Personal Digital Assistants (PDA's), more users use the wireless internet, and advancements of wireless communication technologies provide the users with various types of network environments.
FIG. 1 is a view for showing environments for heterogeneous networks.
The wireless Internet users can use various types of network environments. As shown in FIG. 1 , heterogeneous network environments can include Institute of Electrical and Electronics Engineers (IEEE) 802.11 20, IEEE 802.16 30, Wideband-CDMA (W-CDMA) 40, and so on, and, in such wireless internet environments, a mobile terminal 10 can frequently move around and change its network connection point.
In order to enable the mobile terminal 10 to communicate over the wireless Internet, even though the mobile terminal 10 moves to a certain network area beyond its current network area, the mobile terminal 10 in the certain network area should receive the same high quality Internet services as in the current network area.
That is, the mobile terminal 10 has to perform seamless communications, so that a handoff concept is applied. The handoff refers to a function of transferring a process for communications from an access node for the current network area to an access node for another network area.
Meanwhile, recently, the developments of Internet technologies generalize real-time multi-media services such as Video On Demand (VOD), Audio On Demand (AOD), videophones, video chatting, and the like. Specifically, the mobile terminal 10 can be used to get real-time multi-media services together with advancements of the wireless Internet technologies and improvements of the data processing capacity of the mobile terminal 10 .
Together with the advancements of the technologies as above, users can be provided with real-time multi-media services through the mobile terminal 10 while moving. Accordingly, lots of studies are continuing on methods enabling effective handoffs to be performed as users roam around.
Heterogeneous networks support different bandwidths one another, but most of the conventional handoff-processing methods for the mobile terminal 10 do not take into consideration the differences among the transmission bandwidths supported by networks to which the mobile terminal 10 is connected before and after the mobile terminal 10 roams around.
For example, if the mobile terminal 10 moves from an area of the Wireless Local Area Network (WLAN) to an area of the 3 Generation Partnership Project (3GPP) network, there exists a transmission bandwidth difference among the two networks since the bandwidth of the WLAN is larger than or equal to 384 Kbps and the bandwidth of the 3GPP network is smaller than 384 Kbps.
As above, if the bandwidth supported by a network before the movement is larger than the bandwidth supported by a network after the movement, the loss of data packets caused by the bandwidth difference cannot be compensated for. Accordingly, there exists a problem of degrading the qualities of real-time multi-media services.
Further, the conventional handoff-processing method for the mobile terminal 10 can be described as below in brief. That is, when the mobile terminal 10 requests a handoff to the access node in a network area to which the mobile terminal 10 moves, the access node allows the handoff if the resources of the network to which the access node belongs are sufficient.
Failing to reserve resources in the network to which the mobile terminal 10 is going to move, the mobile terminal 10 requests again the handoff until finding out another network that has sufficient resources. Thus, there exists a problem that it takes time excessively for retries for resources reservations until the mobile terminal 10 finds out a network having sufficient resources as networks are more overlapped in number.
SUMMARY OF THE INVENTION
Illustrative, non-limiting embodiments of the present invention have been developed in order to solve the above disadvantages and other problems associated with the conventional arrangement. Also, the present invention is not required to overcome the disadvantages described above, and an illustrative, non-limiting embodiment of the present invention may not overcome any of the problems described above. An aspect of the present invention is to provide a handoff system and method among heterogeneous networks, and a mobile terminal using the same and an operating method therefor, capable of seamlessly performing a handoff to the most suitable network in aspect of resources of data-link layers and network layers by detecting all handoff-available heterogeneous networks and performing a handoff to one of the detected networks that has the best wireless communication quality.
According to an aspect of the present invention there is provided a handoff system among heterogeneous networks, comprising: plural access nodes which supports wireless communication; and a crossover node which selects an access node for a handoff among the plural access nodes. In selecting the access node, the crossover node may rely on a predetermined condition comprising at least one of wireless communication quality and a network bandwidth which supports the selected access node.
Preferably, but not necessarily, the mobile terminal is configured to generate a handoff request signal which initiates selecting of the access node, wherein the handoff request signal comprises at least one of an identification (ID) of the mobile terminal and the predetermined condition.
Preferably, but not necessarily, the access node comprises one of an access point and a Base Transceiver System (BTS).
Preferably, but not necessarily, the crossover node selects an access node having best wireless communication quality from an access node list created by the mobile terminal. The access node list comprises accessible access nodes which have been searched for by the mobile terminal.
Preferably, but not necessarily, the access node notifies the crossover node of a resources reservation failure if a resources reservation request has been received from the crossover node and resources of a network to which the access node belongs are insufficient. In here, upon receiving the resources reservation failure from the access node, the crossover node selects another access node from the plural access nodes and reserves resources at the selected other access node.
Another aspect of the present invention is to provide a handoff method among heterogeneous networks comprising plural access nodes which supports wireless communication. The handoff method comprises: selecting an access node for a handoff among the plural access nodes; and selecting another access node for the handoff among the plural access nodes without sending a selection failure notice to the mobile terminal, if the selected access node is determined to be still inappropriate for the handoff. The operation of selecting of the access node may be performed according to a predetermined condition comprising at least one of wireless communication quality and a network bandwidth which supports the selected access node.
Preferably, but not necessarily, the handoff method further comprises generating a handoff request signal by which selecting of the access node is initiated. The handoff signal used in the handoff method may comprise at least one of the identification (ID) of the mobile terminal and the predetermined condition.
Preferably, but not necessarily, the access node used in the handoff method comprises one of an access point and a Base Transceiver System (BTS).
Preferably, but not necessarily, selecting of the access node comprises reserving resources of a network to which the access node belongs after having selected the access node having a best wireless communication quality. Here, the handoff method may further comprise operations of sending a resource reservation request to the access node, and receiving one of a resource reservation success notice if resources of the network are sufficient and a resource reservation failure notice if resources of the network are insufficient.
Preferably, but not necessarily, the handoff method may further comprise operations of selecting another access node out of the plural access nodes for resource reservation if the resource reservation failure notice has been received.
Still another aspect of the present invention is to provide a mobile terminal applied to a handoff system among heterogeneous networks. The mobile terminal comprises an access node search unit which searches for accessible access nodes among plural access nodes; a list-creating unit which creates a list of the searched-for access nodes; and a network interface unit which sends a handoff request signal comprising at least one of an identification (ID) of the mobile terminal, a predetermined condition used in selecting an access node from the access node list, and a handoff request signal.
There is also provided an operation method for a mobile terminal applied to a handoff system among heterogeneous networks, comprising searching plural access nodes for accessible access nodes; creating a list of the searched-for access nodes; and creating a handoff request signal comprising the created access node list; and requesting for a handoff.
BRIEF DESCRIPTION OF THE DRAWINGS
The above aspects and features of the present invention will be more apparent by describing certain embodiments of the present invention with reference to the accompanying drawings, in which:
FIG. 1 is a view for exemplarily showing heterogeneous network environments;
FIG. 2 is a view for explaining a handoff system among heterogeneous networks according to an exemplary embodiment of the present invention;
FIG. 3 is a block diagram for showing a mobile terminal according to an exemplary embodiment of the present invention;
FIG. 4 is a flow chart for explaining a handoff method among heterogeneous networks according to an exemplary embodiment of the present invention; and
FIG. 5 is a flow chart for showing signal flows for performing the handoff method among heterogeneous networks as shown in FIG. 4 .
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
Hereafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 2 is a view for explaining a handoff system among heterogeneous networks according to an exemplary embodiment of the present invention.
In FIG. 2 , a handoff system among heterogeneous networks according to an exemplary embodiment of the present invention has a mobile terminal 300 roaming around heterogeneous networks, that is, roaming from a first network area 100 to a second network area 200 , and a crossover node 600 for connecting the first and second network areas 100 and 200 . Further, the first and second network areas 100 and 200 contain a first access node 400 and a second access node 500 , respectively.
The first and second network areas 100 and 200 are heterogeneous networks supporting different bandwidths respectively. For example, the first network area 100 can be a WLAN area supporting a bandwidth higher than 384 Kbps, and the second network area 200 can be a 3GPP area supporting a bandwidth lower than 384 Kbps.
FIG. 2 shows two accessible heterogeneous networks, but the present invention is not limited to FIG. 2 , but can be applied to all wireless networks of various kinds.
The mobile terminal (MT) 300 performs wireless communications with the first and second access nodes 400 and 500 in the first and second network areas 100 and 200 , and the mobile terminal can be any of diverse terminals such as a handheld computer, a PDA and a mobile phone which are capable of performing wireless communications.
Such a mobile terminal 300 can roam around at any time under wireless Internet environments and change its own network access point. That is, the mobile terminal 300 performs a handoff. To do so, the mobile terminal 300 according to an exemplary embodiment of the present invention searches access nodes, creates an access node list, and sends a handoff request signal. The mobile terminal 300 will be described in detail with reference to FIG. 3 to be later described.
The first access node (AN) 400 provides a wireless communication interface in the first network area 100 , and sends and receives data to and from the crossover node 600 . In here, the first access node 400 can be either an access point (AP) or a Base Transceiver System (BTS).
In the present exemplary embodiment, it is shown that a mobile terminal 300 moves from the first network area 100 to the second network area 200 , so the first access node 400 receives a handoff request signal from the mobile terminal 300 and sends the handoff request signal to the crossover node 600 .
The second access node 500 provides a wireless communication interface in the second network area 200 , and sends and receives data to and from the crossover node 600 . In here, like the first access node 400 , the second access node 500 can be either an access point (AP) or a Base Transceiver System (BTS).
The second access node 500 in the present exemplary embodiment checks whether resources of its network are sufficient, if it receives a resource reservation request from the crossover node 600 . Next, the second access node 500 notifies the crossover node 600 of a resource reservation success, if the resources are sufficient, and notifies the crossover node 600 of a resource reservation failure, if the resources are insufficient.
The crossover node 600 sends and receives data to and from the first and second access nodes 400 and 500 . According to the present exemplary embodiment, upon receiving a handoff request signal from the mobile terminal 300 , the crossover node 600 selects, for resource reservation, an access node from the access node list received together with the handoff request signal.
Preferably, but not necessarily, the crossover node 600 can select an access node belonging to a network having the best wireless communication quality out of plural access nodes contained in the access node list. In here, there can be a method using the strength of a received signal and a method using an amount of power of a received signal for checking the wireless communication quality of a network.
Further, notified of a resource reservation failure by the second access node 500 , the crossover node 600 selects, for resources reservation, different access nodes in order of wireless communication quality from highest to lowest out of plural access nodes contained in the access node list.
FIG. 3 is a block diagram for showing a mobile terminal according to an exemplary embodiment of the present invention.
As shown in FIG. 3 , a mobile terminal 300 according to an exemplary embodiment of the present invention has an access node search unit 310 , a list-creating unit 320 , a network interface unit 340 , and a control unit 330 .
The access node search unit 310 searches an accessible access node among the plural access nodes. Preferably, but not necessarily, the access node search unit 310 can use the scanning of data-link layer L 2 in order to search for the accessible access nodes.
That is, the access node search unit 310 can detect handoff-available networks and catch their L 2 identifiers, such as a Media Access Control (MAC) address and a Cell ID, using the L 2 scanning.
The list-creating unit 320 creates an access node list for the accessible access nodes searched by the access node search unit 310 .
The control unit 330 creates a handoff request signal containing the access node list created by the list-creating unit 320 , and controls the network interface 340 so as to send the created handoff request signal.
In here, the handoff request signal created by-the control unit 330 can further contain the identifier ID of the mobile terminal 300 , that is, its own ID, and a required transmission bandwidth, in addition to the access node list. Preferably, but not necessarily, the access node list can be created in order of wireless communication quality from highest to lowest.
The network interface 340 , according to the control of the control unit 330 , sends the handoff request signal to the crossover node 600 through the access node of the network currently occupied, that is, through the first access node 400 .
FIG. 4 is a flow chart for explaining a handoff method among heterogeneous networks according to an exemplary embodiment of the present invention. In here, description will be made on a handoff method among heterogeneous networks with reference to FIGS. 2 to 4 according to an exemplary embodiment of the present invention.
As shown in FIG. 2 , when a mobile terminal 300 moves from the first network area 100 to the second network area 200 , that is, when in need of performing a handoff, the mobile terminal 300 causes the access node search unit 310 to search the plural access nodes for accessible access nodes (S 700 ).
When the accessible access nodes are completely searched for, the mobile terminal 300 causes the list-creating unit 320 to create an access node list for the accessible access nodes (S 710 ). In FIG. 2 , the access node list contains the ID of the second access node 500 . In here, the mobile terminal 300 preferably, but not necessarily, creates the access node list in order of wireless communication quality from highest to lowest.
The mobile terminal 300 causes the control unit 330 to create a handoff request signal containing an access node list and causes the network interface unit 340 to send the hand off request signal to the first access node 400 , and the first access node 400 sends the handoff request signal received from the mobile terminal 300 to the crossover node 600 (S 720 ).
The crossover node 600 that has received a handoff request signal from the first access node 400 selects, for resources reservation, the second access node 500 which is an access node belonging to a network having the best quality, out of the access node list contained in the received handoff request signal (S 730 ). In here, if the mobile terminal 300 creates the access node list in order of wireless communication quality from highest to lowest, the crossover node 600 reserves resources of an access node first appearing on the access node list.
The second access node 500 that has received a resource reservation request from the crossover node 600 checks whether the resources of the network to which it belongs are sufficient (S 740 ). That is, the second access node 500 checks whether to provide the transmission bandwidth needed for the mobile terminal 300 .
If the second access node 500 decides in the step S 740 that the resources of the network to which it belongs are sufficient for the mobile terminal 300 , the second access node 500 notifies the crossover node 600 of sufficient resources and performs the handoff (S 750 ).
If the second access node 500 decides in the step S 740 that the resources of the network to which it belongs are insufficient for the mobile terminal 300 , the second access node 500 notifies the crossover node 600 of insufficient resources.
Next, the crossover node 600 selects another access node out of the access node list, and reserves resources (S 730 ). These steps are repeated until an access node having sufficient resources is found.
FIG. 5 is a flow chart for showing signal flows for a method performing a handoff among heterogeneous networks of FIG. 4 . In here, description will be made on signal flows for a method performing a handoff among heterogeneous networks with reference to FIGS. 2 to 5 .
However, in here, description will be made on a handoff method for a system having the first access node 400 of the first network 100 area in which the mobile terminal 300 is located and the second access node 500 and third access node of the second network area 200 and the third network area to which the mobile terminal 300 moves.
The mobile terminal 300 searches an accessible access node (AN) among the plural access nodes (S 800 ). In here, the accessible access nodes are the second and third access nodes.
If the accessible access nodes are completely searched for, the mobile terminal 300 creates an access node list (AN_ID List) of the searched accessible access nodes (S 810 ).
The mobile terminal 300 sends a handoff request signal to the first access node 400 , and the first access node 400 sends the handoff request signal to the crossover node 600 (S 820 ). In here, the handoff request signal can contain the identifier of the mobile terminal 300 (MT_ID), that is, its own ID, the access node list (AN_ID List), and a required transmission bandwidth (Required B/W).
The crossover node 600 that has received the handoff request signal selects out of the AN_ID List an access node to which the handoff is requested (S 830 ). In here, the second access node is assumed to have the best wireless communication quality among the access nodes contained in the AN_ID List.
The crossover node 600 sends to the second access node 500 a signal Resource_Reservation_Request for reserving resources (S 840 ). In here, the resource reservation signal can contain the MT_ID and Required B/W.
The second access node 500 receives a resource reservation signal from the crossover node 600 , and checks whether the resources of the network to which it belongs are sufficient. In here, it is assumed that the resources of the network to which the second access node belongs are insufficient (S 850 ).
The second access node 500 sends a signal Resource_Reservation_Fail notifying the crossover node 600 of resources reservation failure (S 860 ). In here, the resources reservation failure notification signal can contain the MT_ID, Required B/W, and a cause of the resources reservation failure.
The crossover node 600 selects out of the AN_ID List the third access node as an access node to perform the handoff, in which the third access node has the wireless communication quality immediately lower in order than the second access node 500 (S 870 ).
If one access node is selected, the crossover node 600 sends again a signal Resource_Reservation_Request for reserving resources to the selected access node, that is, the third access node (S 880 ). In here, the resources reservation signal can also contain the MT_ID and Required B/W.
The third access node that has received a resources reservation signal from the crossover node 600 checks whether the resources of the network to which it belongs are sufficient. In here, the resources of the network to which the third access node belongs are assumed to be sufficient for the handoff of the mobile terminal 300 (S 890 ).
Since the resources of the network to which the third access node belongs are sufficient, the third access node sends a signal Resource_Reservation_Success notifying the crossover node 600 that the resources reservation has been successful (S 892 ). In here, the resources reservation success notification signal can contain the MT_ID, candidate EP, and allocated transmission bandwidth (Allocated B/W).
Next, the crossover node 600 sends a signal Handoff_Success notifying the first access node 400 of the successful handoff, and the first access node 400 sends the mobile terminal 300 the handoff success notification signal received from the crossover node 600 . In here, the handoff success notification signal can contain the MT_ID, selected access node ID, that is, the third access node ID, candidate EP, and allocated transmission bandwidth.
As described in FIG. 4 , the handoff system and method among heterogeneous networks according to an exemplary embodiment of the present invention let the crossover node 600 reserve resources of the third access node automatically if failed to reserve resources of the second access node 500 .
Accordingly, the exemplary embodiment of the present invention can omit a step of sending the first access node 400 and the mobile terminal 300 a signal notifying of resources reservation failure if the resources reservation of the second access node 50 failed. Further, the exemplary embodiment of the present invention can omit a step for the mobile terminal 300 to send again the crossover node 600 a signal requesting for a handoff.
As described above, the handoff system and method among heterogeneous networks and the mobile terminal employing the same and the operation method thereof let a mobile terminal detect all the heterogeneous networks to which a handoff can be performed, and perform the handoff to one of the detected networks which has the best wireless communication quality, bringing out an advantage capable of seamlessly performing a handoff to the most suitable network in aspect of resources of data-link layers and network layers.
Further, as above, the exemplary embodiment of the present invention can reduce the number of times of repeated resource reservation signal transmission for searching for an appropriate wireless heterogeneous network, so it has an advantage capable of remarkably reducing resource reservation time which is likely to increase as the number of heterogeneous networks increases.
The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. Also, the description of exemplary embodiments of the present invention is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art. | Disclosed are a handoff system and a method among heterogeneous networks. The handoff system among heterogeneous networks has plural access nodes which supports wireless communication with a mobile terminal; and a crossover node which selects resources of an access node to which a handoff is made without repetitive communications between access modes and the mobile terminal in selecting an access node. The handoff system performs a handoff to a network if resources of the network are sufficient for wireless communication. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation application of U.S. Non-Provisional application Ser. No. 13/568,807, filed Aug. 7, 2012, now allowed, which is a continuation-in-part application of U.S. Non-Provisional application Ser. No. 13/536,013 filed Jun. 28, 2012, abandoned, which claims priority to U.S. Provisional Application No. 61/502,460 filed Jun. 29, 2011, all three of which are incorporated herein by reference in their entireties.
FIELD OF THE INVENTION
This invention relates generally to the field of pole supports, specifically including, without limitation, precast concrete pole support bases and methods of manufacture, installation and use.
BACKGROUND
A wide variety of poles and posts are used throughout the world, including lighting poles, electrical, telephone and cable supports and numerous other poles of many different types. Some of these poles are installed by placing a portion of the lower end of the pole in a hole in the ground and filling the remaining space in the hole with soil, concrete or another suitable material. Many wooden poles are installed using this method in which a portion of the pole is buried in the ground. Other poles and similar structures are intended for installation with the lower end of the pole resting on a separate base, the top of which may be positioned at ground level or above ground level. Metal lamp posts are but one of many such poles, posts and other structures frequently installed on a separate, typically concrete, base.
Many poles or posts intended for installation on top of a base or support have attached to the bottom of the pole a horizontal square plate or other structure with a “square” arrangement of four holes, with one hole near each of the four corners of the plate or other structure. This provides four fastening holes arranged at the corners of a square so that each hole is equally distant from each of the other two holes adjacent to it. Each of the holes may be located, for instance, in a foot or boss protruding from the side or end of the pole or a plate secured to the lower end of the pole.
Such a pole is typically installed by securing the plate or other pole-terminating structure with four studs, bolts or other fasteners: (a) protruding vertically from the concrete base and up through the plate or other structure or (b) passing down through the holes in the pole base plate or other structure and into the concrete base. Where studs, pins, bolts or the like are positioned to be received in the holes in the pole base plate or other hole-containing structure, the fasteners must be located carefully during preparation of the base or foundation in order to insure that the fastener spacing matches the locations of the holes in the pole plate or other hole-containing structure. Each stud, pin, bolt or the like is usually the upper end of a long rod or is attached to such a rod or other anchor that extends well down into the base or foundation on which the pole is to be installed.
If one or more studs protruding from a concrete base are sheered off, as often happens when a motor vehicle collides with a pole mounted on such a concrete base, replacement of the pole may be difficult because of the difficulty of attaching new studs to the concrete base.
SUMMARY
The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings and each claim.
This invention provides a pole base, which may be a prefabricated concrete pole base, and that may have an adjustable connection or attachment structure and system of use that is simple to manufacture and install, highly versatile and easy to use. This invention can be used in a wide variety of configurations and alternative structures using numerous known materials and additional suitable materials and components that may be developed in the future.
The attachment structure is adapted to accommodate pole base plates or other structure having differing dimensions. In one embodiment, an X-shaped arrangement of U-shaped cross section (or inverted T-shaped slot) channels support and attach to the bottom of a pole.
The channels may be secured to a pole base body that is typically generally cylindrical in shape with generally round, planar top and bottom surfaces. The height may be approximately four times the diameter of the cylindrical body, but many other proportions and shapes are possible. The body may include one or first and second planar recessed regions disposed on opposing sides with inwardly tapered horizontal surfaces on the top and bottom of the recess. Alternate embodiments of the invention may have various proportions of recess depths and sizes and locations. The channels can be embedded in a square or rectangular protrusion from the planar top of the body or can be embedded directly in the top of the body.
The body may also contain one or more electrical wire chase conduits. The conduits usually run continuous from the top central region of the body and extend downward and exit the body in different desired directions at a side or the bottom.
A lifting anchor may be fastened to the concrete form so that a portion of it protrudes from the bottom of the body. This anchor or hook facilitates lifting and moving the base during and after manufacture, particularly if the base is manufactured upside down.
If one or more studs or bolts securing a pole to the concrete base of this invention are sheered or otherwise broken off, as may happen when a motor vehicle collides with a pole mounted on such a concrete base, replacement of the pole may be easy. This is because the sheered stud or bolt can be easily removed from the channel to which it was secure and replaced, and the pole (if undamaged) or a replacement pole can be mounted on the base as described above. Moreover, the pole bases of this invention make it quick and easy to change poles or pole types mounted on the base.
BRIEF DESCRIPTION OF THE DRAWINGS
Illustrative embodiments of the present invention are described in detail below with reference to the following drawing figures:
FIG. 1 is an perspective view of the top and a side of one embodiment of the base of this invention.
FIG. 2 an exploded perspective view of the attachment components incorporated in the base depicted in FIG. 1 , together with the lower portion of a pole and pole base plate of a type that may be installed on the base depicted in FIG. 1 .
FIG. 3 is a side view of the base of FIG. 1 .
FIG. 4 is a top view of the base of FIG. 1 .
FIG. 5 is an “x-ray-like” version of the same a view as FIG. 3 , in which internal structure is visible.
FIG. 6 is a perspective view of the top of the base depicted in FIG. 1 with lifting tackle positioned for insertion.
FIG. 7 is a perspective view of the top of the base depicted in FIG. 1 like FIG. 6 but with lifting tackle inserted for lifting the base.
FIG. 8 is a perspective view similar to FIG. 1 of the top and side an alternative embodiment of the pole base of this invention.
FIG. 9 is a perspective view similar to FIG. 1 of the top and a side of another embodiment of the base of this invention.
FIG. 10 is an exploded elevation view of an alternative channel and fastener subassembly of the pole base of this invention.
DETAILED DESCRIPTION
The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.
One embodiment of this invention is a manufactured or prefabricated, typically concrete pole base with an adjustable connection enabling use of the base to support and stabilize light poles, signs, posts and other monopoles having a range of different sizes of attachment plates or other structures. Other embodiments may not be manufactured or prefabricated remote from the location where used or may have numerous other differences.
The figures depict an exemplary embodiment of the invention in which a generally cylindrical base 10 has a concrete body 11 having a cylindrical wall 12 , a top 14 , a bottom 16 and two recesses 18 and 20 . Recesses 18 and 20 have rectangular, vertical planar portions 22 that intersect the cylindrical wall 12 at vertical arises 24 and 26 , the tops and bottoms of which transition to the cylindrical wall 12 along sloping upper transitions 28 and lower transitions 30 , as depicted in FIG. 9 . Alternatively, recesses 18 and 20 can extend all the way from upper transitions 28 through the bottom 16 of the body, as depicted in FIG. 1 .
As depicted in FIG. 9 , a notch 29 may be cast in the side of body 11 to indicate “grade,” i.e., the depth to which the base 10 is to be buried during installation, where the portion of the body 11 above the notch 29 projects above “grade,” or the level of the ground. Notch 29 can be V-shaped or another shape, and other shapes than a notch may be utilized as such an indicator of grade. Other indicia can also be used, including, for instance and without limitation, a metal piece or other object embedded in and visible in or projecting from the body 11 , and a marking such as paint applied to the base 11 . A recess such as notch 29 formed by mold structure is a practical indicator of grade because it is automatically and accurately incorporated in the body 11 when base 10 is manufactured.
Structure for attaching a pole to the base 10 is provided by anchors 32 easily seen in FIG. 2 . Each anchor 32 may comprise a section of channel 34 positioned in use horizontally on or in the top of body 11 . Structure attached to the undersides 40 of anchors 32 is embedded, together with a portion of the anchor 32 , in the base 10 to secure the anchor in place. Such securing structure in a first exemplary embodiment depicted in the drawings is two vertical plates 38 and two vertical rods 36 , each of which rods 36 is attached to one of the plates 38 and the underside 40 of one of the channels 34 . Many other securing structures may be used such as the coupling 94 and threaded rod 100 shown in FIG. 10 . Coaxial or aligned pairs of anchors 32 are positioned orthogonal to each other so that the channel axes 42 and 44 and the channels 34 form an X-shape, as may be easily seen in FIG. 4 . This permits a pole 46 having a square base plate 48 penetrated by four corner holes 50 to be attached to the base 10 with four bolts, studs or other fasteners 52 typically (but not necessarily) having rectangular heads 54 , one of which heads 54 is received in each of channels 34 . Because the fastener heads 54 can be positioned in the channels 34 anywhere along the length of the channel, base plates 48 of different sizes can be attached to base 10 , provided that the base plate 48 can be positioned so that each of the holes 50 in the base plate 48 is over a portion of one of the channels 34 . The same is true of pole attachment holes in other pole termination structures.
As an alternative to bolts, studs or other fasteners 52 positioned with heads 54 received in the channels 34 , “T-nuts” and other internally threaded fasteners can be positioned in the channels, and bolts or other fasteners 52 can be passed down through the holes 50 in pole base plate 48 , or through other hole-containing structure of pole 46 , and into the T-nuts or other internally threaded fasteners.
The base 10 is formed with the channels 34 of anchors 32 at the top 14 of the body 11 and with rods 36 and plates 38 imbedded in the concrete or other material of which the body 11 is cast or otherwise formed. Concrete or other material of which the body 11 is formed can also be positioned between the channels 34 to form an integral monument-like structure 41 on the top of base 10 , or the channels can be partially or fully embedded in the body 11 .
The X-shaped arrangement of anchors 32 for securing a pole base plate 48 can be attached to other structures such as poured-in-place and prefabricated bases, concrete pads, or building, dam, parking lot, pedestrian walkway, landscaped area, street or road components. Anchors 32 can also be configured as channels secured to other components by bolts, studs or other fasteners passing through or attached to the bottoms 35 or sides 37 of channels 34 .
In addition to the anchors 32 , reinforcing structure 56 , conduits 58 , other desired structures such as an anchor or hook 60 can be imbedded in body 11 to reinforce and strengthen the body 11 , facilitate connection of electrical or other devices in or on the pole 46 to power sources, controls or other devices and provide lifting structure.
Reinforcement 56 (visible in FIG. 5 ) can include vertical rebar 62 and generally horizontal, square rebar stirrups 64 . These vertical and horizontal members can be held together for placement in the concrete mold with rebar tie wires, can be welded or can be separate components.
Conduit 58 can run from the top 14 of the body 11 inside the channels 34 , down the inside of the body 11 and out through a side of the base 10 through cylindrical wall 12 or one of the planar portions 22 or 28 of one of the recesses 18 or 20 . Such positioning of an upper end 68 of conduit 58 in a central location inside the body 11 and channels 34 positions wires or other structures positioned in the conduit 58 to travel directly up the inside of pole 46 . While the conduit 58 can bend inside the base and exit to the side, conduit 58 could also exit the bottom 16 of the base 10 .
Junction boxes or other desirable structures or components can be positioned on or in body 11 as may be desirable to achieve additional or improved functionality.
Base 10 may be manufactured utilizing a concrete form having multiple connected panels that, when connected, define voids in which embedded structures like reinforcement 56 , portions of anchors 32 and conduit 58 are positioned and into which the concrete mixture or other material from which the base is formed is poured. Such a form may be a clam-shell opening form or any other form suitable for manufacturing concrete structures like base 10 .
Alternate embodiments of the invention may have various proportions of recess depths and sizes, thereby allowing for the addition or subtraction of mass and thus weight to the body as needed and to provide roll-resisting structure and for other purposes.
Anchors 32 with fastening channels 34 may be “Halfen,” “Unistrut” or other similar anchoring channels having a generally U-shaped cross section. Lips on the opposed inside ends of the “U,” together with inside walls of the channel form an inverted T-shaped slot and retain appropriately shaped nuts and bolt heads. Such fasteners are sometimes referred to as “Tee-nuts” and Tee-bolts.” Anchors 32 also may be obtained from other suppliers or can be fabricated for this application. Anchors 32 can be a wide variety of different sizes and can have a wide variety of different forms provided that the anchor provides structure for attachment of a nut, bolt, stud or other fastener structure that is securely attached or anchored to the base 10 .
The channels 34 are positioned in horizontal positions at the top of the body 11 in a generally X-shaped arrangement, with the outer ends of the channels at the corners of the protrusion or monument 41 at the top 14 of the body 11 , and the inner ends 35 of channels 34 facing the center of the protrusion 41 . The protrusion 41 is typically square but can also be a rectangle or another shape and can be omitted so that the channels 34 simply sit on top of the body or are partially or fully embedded (as depicted in FIG. 8 ) in the top of body 11 of pole base 15 . If the channels 34 are embedded in the body 11 , the outer ends 39 of channels 34 may be flush with the wall 12 of body 11 as shown in FIG. 8 , but they need not necessarily be flush with the wall 12 .
While it can be beneficial for the outer ends 39 of channels 34 to be open to provide access for positioning or securing fasteners, they need not necessarily be open and can be embedded in the body 11 of base 10 or 15 if either the inner ends of the channels 34 are open so that fasteners can be introduced through the inner ends or if the base 10 or 15 is manufactured with fasteners already positioned in the channels 34 .
The fastening channels 34 each have one or more structures, which can be one or more anchoring bars 36 or plates 38 (see FIG. 2 ) or other shapes (see FIG. 10 ), fastened to the bottom 40 of the channel 34 and extending downward into the body 11 , thereby acting to strengthen the connection between each channel 34 and the body 11 . The fastening hardware (typically tee-head bolts or studs or nuts) used to fasten the base of the pole to the channels may be common hardware used in Halfen, Unistrut or similar anchoring structures.
Such Halfen, Unistrut or similar anchors 32 will typically include a channel 34 having a generally U-shaped cross section with an open top forming an inverted T-shaped slot. The channels 34 need to be open at least one end and may have a length typically somewhat less than half of the radius of the cylindrical base 10 ; however, other anchor structures and dimensions may be used.
Having the center of the “X-shaped” anchor 32 channels 34 open provides an unobstructed region for the conduits 58 to open to the top of the base 10 . However, a complete “X-Shaped” structure could be used by having equal length channels 34 that meet in the middle or by having one longer channel 34 and two shorter channels 34 abutting the longer channel on opposite sides in its middle. If one longer and two shorter channels 34 are used, two of the fasteners 52 will be secured in the longer channel 34 , and one will be secured in each of the shorter channels 34 . Conduits 58 could open to the top of body 11 just to one side of the abutting channels 34 in these alternative configurations.
If abutting channels are welded or otherwise attached to the channel they abut, the desired orientation of the “X-shaped” channels 34 structure can be easily maintained during manufacture of the base 10 . Where the channels 34 do not abut, other means will have to be used to maintain the proper relative orientation of the channels during manufacture of the base 10 or during incorporation of the anchors 32 in another structure.
An alternative channel and fastener structure is depicted in FIG. 10 . In this alternative, channel 76 is similar to channels 34 , but depending sharp or v-shaped lips 78 extend downward from the inward-extending tops 80 of the channel 76 , forming inverted v-shaped recesses 84 between the side walls 82 and the lips 78 . These recesses 84 receive protrusions 86 on square or rectangular washers 88 through which bolts 90 pass into nuts 92 . This arrangement of components and structures can provide especially strong attachment structures, particularly including resistance to force exerted on the fasteners, because, among other reasons, of the engagement between the lips 78 of channel 76 and protrusions 86 of washer washers 88 .
Channel 76 rests on and is welded (e.g. with weld bead 102 ) or otherwise appropriately attached to a threaded coupler 94 . In the embodiment of coupler 94 depicted in FIG. 10 , a plate 96 to which the channel 76 is attached is welded to or otherwise attached to or formed with a threaded collar 98 . Threaded rod 100 seated in collar 98 extends down into the concrete of body 11 . One, two or any other suitable number of threaded couplers 94 and rods 100 may be attached to each channel 76
A lifting anchor 60 visible in FIG. 5 is fastened to the main concrete form (not shown) in a manner so as to dispose it at the bottom 16 of the body 11 , sufficiently inward from the wall 12 of the body 11 to allow a substantial portion of the anchor 60 to be embedded in the body 11 . The lifting anchor 60 may vary in type and size while still performing the intended purpose and function of providing a structure by which base 10 can be lifted.
The reinforcing structure 56 is positioned in the form (not shown) prior to the introduction of concrete mixture or other material of which the body is formed and will serve to reinforce the structural integrity of the base body 11 when the fabrication process is complete. Reinforcement 56 may be comprised of one or a multitude of steel reinforcement members in the form of a single reinforcing member or a framework of multiple reinforcing members that form a structure having a diameter, length, width, and height that are sufficiently less than the diameter, length, width, and height of the interior volume of the body 11 to insure that concrete completely surrounds the reinforcement 56 . Reinforcement structure 56 may be constructed of a variety of different suitable materials including but not limited in use to, metals, polymers, fiberglass, carbon fibers, metal/plastic composites, and other materials that perform the same desired functions.
After positioning of all components within the concrete form, a concrete mixture, typically but not necessarily a high grade concrete mixture, is poured into the main concrete form, surrounding the entirety of the main interior reinforcing components.
Once the concrete is at least partially cured or hardened, the base 10 is removed from the form, is allowed to cure fully and, optionally, is finished by a variety of methods including but not limited to, texturing, staining, etching, polishing, glazing, sealing, color coating, and other finish methods.
Body 11 may be manufactured using concrete of numerous types and composition mixes having various combinations of ingredients such as cement, water, cementitious materials, and chemical and or mineral admixtures or coloring agents. Concrete usable for manufacturing the concrete base of this invention may be regular concrete, including high grade concrete, and it may be polymer concrete or a wide variety of other concrete types, including, without limitation, high strength concrete, high performance concrete, ultra-high-performance concrete, glass concrete, asphalt concrete, rapid strength concrete, geopolymer concrete and green concrete. Other types of concrete and materials other than concrete also may be used, provided that such materials provide appropriate mass, strength and ability to hold the channels and other components required for the poles to be supported and the conditions of the intended installation.
Body 11 and base 10 may be manufactured in a variety of shapes other than cylindrical, including, but not limited to, triangular, square, pentagonal, hexagonal, heptagonal, octagonal, rectangular or any other polygonal shape, or ovoid, elliptical or another rounded shape, as viewed from the top or in cross section. Body 11 and base 10 shapes other than round may resist rotation in situ better than entirely round shapes. Body 11 may be irregular along its length and may have yet other shapes, including, for instance, a truncated cone tapering from its bottom up, as well as other shapes that provide the needed strength, stability and other properties desired or needed for a particular pole base.
This invention is intended to be used for applications including, but not limited to, as a mounting and stabilizing support for light poles, sign posts, sign panels, traffic light poles, flag poles, radar equipment mounting poles, communication equipment mounting poles, solar panel array mounting poles, wind turbine poles, or other applications for mounting, support and stabilization.
The X-shaped configuration of channels (easily seen in FIG. 2 ) can be used in cast-in-place concrete or other structures to provide the attachment structure for a variety or range of base plate 48 sizes and bolt receiving hole 50 spacings.
Pole base 10 may be installed by lifting the base 10 by a lifting harness 72 attached to eye-bolts, Tee-cross section slot-fillers 74 or other hardware temporally attached to one or more of channels 34 , as depicted in FIGS. 6 and 7 . The base 10 is lowered into a previously excavated hole. Soil, concrete or other suitable fill material is then placed in the hole to secure the base in an upright position. If the body 11 has any recesses 18 or 20 , the fill material will occupy such recesses.
A pole having a square arrangement of stud or bolt-receiving mounting holes, such as pole 46 , may be installed on the base 10 by positioning one anchor bolt or stud 52 in each of the four channel sections 34 (as shown in FIGS. 3 and 4 ) with an end of each stud facing upward and positioning the pole base 48 above and near the channel sections 34 . Before or after positioning the pole base 48 near the channel sections, each of studs 52 may be slid into and positioned in the channel 34 within which it is located so that the stud 52 can be received in one of the pole base holes 50 . The pole 46 may then be lowered so that the pole base 48 holes 50 receive the studs 52 with one of the studs 52 positioned in each of the four base structure holes 50 . The fasteners are then tightened so as to hold the pole base 48 securely connected to the channels.
Alternatively, as is generally illustrated in FIG. 10 , the nut and bolt can be turned over so that a bolt shank is passed through the top of a pole base, into a channel and into a nut or washer and nut in the channel.
Furthermore, the base of this invention can be manufactured with channels having numerous other cross-sectional shapes provided that an X-shaped arrangement of channels is provided to accommodate differing sizes and hole or fastener arrangements in pole bases.
Other embodiments of the pole base of this invention may use fastener arrangements that are not adjustable together with other aspects of the invention described and/or depicted herein and in the accompanying drawings.
The ability of the base 10 of this invention to receive and securely hold poles with different sizes of square arrangements of mounting holes, affords versatility in use of the base and permits a first pole mounted on the base to be replaced by a pole with different size hole arrangements. It also permits a damaged pole or a pole secured with damaged or broken studs to be replaced or remounted without replacing or repairing the base.
Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and subcombinations are useful and may be employed without reference to other features and subcombinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications can be made without departing from the scope of the claims below.
For instance, one or both of the recesses 22 can be omitted or can have different proportions and different shapes. Where there are two recesses 22 , they do not have to have the same shape.
“Soil” used to backfill a hole within which a pole base of this invention is positioned can be any fluid, granular or similar material suitable for securing the pole base in a stable, upright position so that the base can resist any uplift or tilting forces exerted on the base or a pole attached to it. Accordingly, “soil” includes earth, dirt, stone or other aggregate, concrete and any other suitable material. Holes within which pole bases of this invention are positioned can be excavate in undisturbed earth (including loose soil, stone, rock and other materials), in fill, in other naturally occurring or human-made structures like parking lots. | A prefabricated concrete pole base and adjustable method of connection and use to receive, support, and stabilize light poles and the like having different hole mounting patterns, securing the pole to the base and facilitating rapid installation of poles while eliminating the need for on-site concrete forms and lengthy concrete cure times. | 4 |
RELATED APPLICATIONS
[0001] This application is a continuation of pending U.S. patent application Ser. No. 13/410,435 filed Mar. 2, 2012 which is a continuation of pending U.S. patent application Ser. No. 12/910,599, filed on Oct. 22, 2010 and now U.S. Pat. No. 8,151,832, which is a continuation of U.S. patent application Ser. No. 11/701,830 filed Jan. 30, 2007, and now U.S. Pat. No. 7,845,375, which is a continuation-in-part of U.S. patent application Ser. No. 10/922,470, filed Aug. 20, 2004, and now U.S. Pat. No. 7,617,850, and U.S. patent application Ser. No. 10/971,486, filed Oct. 22, 2004 (now abandoned), which was a continuation-in-part of U.S. patent application Ser. No. 10/922,470, filed Aug. 20, 2004 (now abandoned), and which claimed priority to U.S. Provisional Patent Application No. 60/513,662, filed Oct. 23, 2003 and U.S. Provisional Patent Application No. 60/518,904, filed Nov. 10, 2003. Each of the foregoing applications is hereby expressly incorporated by reference in its entirety.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] FIG. 1 illustrates a beverage dispensing system according to an embodiment of the invention;
[0003] FIG. 2 illustrates an alternate embodiment of a beverage dispensing system;
[0004] FIG. 3 is a schematic illustration of a beverage dispensing system according to an embodiment of the invention;
[0005] FIG. 4 is a block diagram of the circuitry employed in the dispensing systems of FIGS. 1 and 2 ;
[0006] FIG. 5 a is a transponder attached to a drinking container in accordance with an embodiment of the invention;
[0007] FIG. 5 b is a transponder integrated into a card;
[0008] FIG. 6 is a flow chart representing a customer's interaction with beverage dispensing system.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0009] FIG. 1 is an illustration of a beverage dispensing system 2 according to one embodiment of the invention. Beverage dispensing system 2 includes a dispenser housing 5 having a top surface 6 , side panels 7 and 8 , front face 9 and back surface (not shown). Also shown is a drip tray 12 , valves 15 - 22 , a display screen 20 , and lever actuators 26 - 33 . Valves 15 - 22 are controlled by corresponding dispensing head electronics (not shown). It should be understood that the basic components of the beverage dispensing system are not limited by this description. For example, display screen 20 may be positioned above housing 5 rather than within front face 9 of housing 5 . Actuators may be levers (as shown), buttons, or any other type of actuator known in the art. The dispensing of beverage may alternatively be activated by sensing a cup below one of valves 15 - 22 . Further, the shape and size of the housing may vary according to the needs of the establishment where beverage dispensing system 2 is to be located.
[0010] With reference to FIG. 2 , the beverage dispensing system may be a dispenser for coffee or other hot beverages. The hot beverage dispensing system is generally indicated at reference numeral 2 ′. Hot beverage dispensing system 2 ′ is shown to include a housing 5 ′ having a top surface 6 ′, side panels 7 ′ and 8 ′, front face 9 ′ and back surface (not shown). Also shown is a drip tray 12 ′, actuators 26 ′- 28 ′, a display screen 20 ′. Although not shown, hot beverage is dispensed through valves positioned below actuators 26 ′- 28 ′. The valves are controlled by corresponding dispensing head electronics (not shown). It should be understood that the basic components of the beverage dispensing system are not limited by this description. For example, display. screen 20 ′ may be positioned above housing 5 ′ rather than within front face 9 ′ of housing 5 ′. Further, the shape and size of the housing may vary according to the needs of the establishment where beverage dispensing system 2 ′ is to be located. The remaining description, unless otherwise indicated, will be presented with reference to cold beverage dispensing system 2 ; however, it should be realized that all of the disclosed features of the embodiments of the invention are equally applicable to hot beverage dispensing system 2 ′. It should also be recognized that the following disclosure is not limited to cold and hot beverage dispensers and is equally applicable to frozen beverage dispensers, Frozen Carbonated Beverage Machines or any other type of beverage dispenser.
[0011] As shown in FIG. 3 , Beverage Dispensing System 2 includes a dispenser 40 , central processing unit (CPU) or controller 60 operatively coupled to actuators 26 - 33 (shown in FIG. 1 ), display screen 20 which functions as a user interface. Beverage dispensing system 2 also includes a relay (not shown) coupled to valves 15 - 22 . Components that provide for remote communication with a customer are also provided. In the embodiment of FIG. 3 , beverage dispensing system 2 is equipped with RFID hardware 62 , which includes an RFID tag reader or interrogator 65 and an antenna 68 . Antenna 68 , which allows information to be sent between an RFID tag 70 and reader 65 , can be any shape or size. For example, antenna 68 may be embedded with in drip tray 12 , as shown in FIG. 1 , or antenna 68 may span the entire width of drip tray 12 or protrude in front of drip tray 12 . Reader 65 is the hardware that determines (using software code) what information is sent/received from CPU 60 . Antenna 68 , which includes a transceiver and decoder, may emit a signal for activating RFID tag 70 for reading and writing data. In addition, antenna 68 includes an antenna housing (not shown) which may be formed from plastic. Antenna 68 may be a high frequency (HF) or ultra high frequency (UHF) type antenna. The UHF antenna may be placed in drip tray 12 . In addition, the antenna housing may include an indicator light that is green when an RFID tag is in communication with RFID hardware 62 and red when no tag is detected in the reading field. Reader 65 decodes the data encoded in an integrated circuit (silicon chip) of tag 70 . The data is then passed on to controller 60 , wherein application software processes the data. In one embodiment, beverage dispensing system 2 may include off the shelf ISO certified RFID readers, antennas, and chips to create a software driven system that can be manipulated to create self serve refill cup programs, track inventory of fountain beverage, ice, and cup inventory.
[0012] In one embodiment antenna 68 is located in a vertical plane in the proximity of beverage dispensing system 2 beneath valves 15 - 22 . As discussed above, reader 65 and antenna 68 are operatively coupled with tag 70 for communicating with the tag 70 . In addition, reader 65 is operatively coupled with controller 60 for communicating with controller 60 . As shown in FIG. 3 , reader 65 may send and receive information from controller 60 via USB cable 72 or serial port cable. In another embodiment, a second antenna (not shown) is provided. The second antenna may be positioned in a horizontal plane attached to drip tray 12 of beverage dispensing system 2 for gathering information and sending information back to RFID tag 70 to be stored. In an alternate embodiment two antennas may be positioned on drip tray 12 (horizontal plane) or two antennas may be positioned in a vertical plane.
[0013] FIG. 4 illustrates one embodiment of suitable RFID circuitry for beverage dispensing system 2 . As shown, the circuitry includes an input/output (I/O) board 85 and a host controller board 86 . I/O board 85 includes an off/on switch 87 , a power providing transformer 88 , a rectifier 89 and two regulators 90 and 91 . Also included are an RFID reader board 92 and a modem 93 , which may be an optical radio modem, inputting information to I/O board 85 . Host controller board 86 may include a clock 94 , which may be a real-time clock. Host controller board 86 may also include a flash 95 , an I/O 96 , a SRAM 97 , a CPU 98 and timers 99 . Host controller board 86 provides the overall operation and data storage at dispensing system 2 . The information can be sent via cellular Ethernet (internet), manual collection at the system, or a portable USB port memory storage device. The information can then be downloaded into a main computer for predetermined calculations, as will be discussed in detail below.
[0014] In the embodiment shown in FIG. 1 , beverage dispensing system 2 includes a display screen 20 for communicating messages to customers. Display screen 20 may be a LCD touch sensor screen. In one embodiment, screen 20 includes a touch sensor keypad through which a customer may enter a numeric code or the like. The code may be a four or five digit code. As will be discussed below, a code may be entered to confirm that a cup/beverage has been paid for or for entry of payment information. An RFID tag is not required when the code is used to pour a beverage. Alternatively, a keypad may be provided separate from display screen 20 . Display screen 20 may be used to display advertisements, interactive tutorial videos, payment instructions, etc.
[0015] As shown in FIG. 3 , a Debit/credit card reader 100 may be coupled to beverage dispensing system 2 . Card reader 100 is adapted to be used with cards having a magnetic strip containing information. The card may be a credit card, debit card or other card containing customer information. For example, in one embodiment the card is a hotel room access card or key card. This enables hotel guests to purchase beverages at the beverage dispensing system and charge the cost to their hotel room bill. Card reader 100 is coupled to beverage dispensing system 2 via wires 101 or other suitable connection devices.
[0016] As discussed above, beverage dispensing system 2 is adapted to communicate with an RFID tag 70 . As shown in FIG. 5 a , RFID tag 70 may be attached to a container or cup 105 . Cup 105 may have a generally cylindrical configuration with an inner wall 107 and an outer wall 108 defining an intermediate air space therebetween. Further, cup 105 may include an upper lip 110 , a bottom 111 , and a handle 112 . RFID tag 70 may also be attached to any other type of container, such as a glass, paper, and bottle or, ice bucket as for ice. RFID tag 70 may be attached to the outer surface 108 of cup 105 by, e.g., an adhesive or fasteners or inlay molded into the plastic when the cup is manufactured. Those skilled in the art recognize that there are various techniques for coupling RFID tag 70 to cup 105 . For example, although not illustrated, RFID tag 70 can be attached to the inner surface 107 of cup 105 . Of course, a protective layer or housing can prevent contact between RFID tag 70 and the liquid held within cup 105 . In one embodiment, RFID tag 70 can be embedded within cup 105 . For example, RFID tag 70 can be embedded between inner wall 107 and outer wall 108 . Cup 105 may be formed by molding around RFID tag 70 . The molding process can be a one step or a multi-step process. For example, a first portion of cup 105 can be molded and then tag 70 can be attached to the first portion. An overlay or second portion can then be formed over both the first portion and tag 70 . Of course, tag 70 can have various shapes and sizes. Tag 70 may have a thickness t1 less than then the thickness of t2 of the walls of cup 105 . Those skilled in the art recognize that various techniques can be employed for embedding the RF receiver in cup 105 . Cup 105 can also be a disposable cup. Those skilled in the art recognize that RFID tag 105 can be used in various other applications. For example, as illustrated in FIG. 5 b , RFID tag 70 can be coupled to a card 110 . Of course, RFID tag 70 could also be coupled to a lid or straw for a cup.
[0017] Tag 70 is adapted to store information relating to at least one of the purchase time, the purchase date, the size of the cup, and the amount of beverage being purchase. An ISO 15693 certified read/write 13.56 MHz RFID tag has the ability to read through water, human tissue and plastic. These ISO certified tags are individually numbered giving the system the ability to individually track each cup in the system. The tags also have anti-collision identification protocols within the ISO 15693 readers allowing multiple transponder or tags to be read simultaneously. In some embodiments, the tags will be passive tags, so the tags will not have a battery source, giving the tag a very long shelf-life. Passive RFID tag may be powered up by RFID antenna to read and write information to the tags. In one embodiment, tag 70 is powered up by a first antenna at a cash register and by a second RFID antenna at the dispensing system. Active tags, which use a battery source, may also be used in applications creating a larger read/write field.
[0018] Tag 70 as described in FIG. 5 a includes 96 bits of storage. However, it should be understood that beverage dispensing system 2 may be used with either a high frequency (HF) or ultra-high frequency (UHF) antenna/reader. HF antennas/readers are less expensive, have smaller read fields and use more costly tags. UHF antennas/readers are more expensive, have larger read fields, and use lower cost tags. Tags may store information including: name, point of initial or last sale, initial or last location field (if the last location field is stored, the data of initial location field can be stored in the record of the transaction). Each tag may have a unique ID. For example, in one day, each location has approximately 520,000 unique IDs available. Tags may be manufactured with a pre-set unique Tag ID. In one embodiment, a software program will keep the last 6 digits of the unique pre-set ID. The probability that different cups will be assigned the same ID is minimized. However, if two cups happen to be assigned the same ID, other differences may be used to distinguish the tags (for example “Cup Volume”, “No Of Units Bought”, etc.) and create a unique combination. If a location is defined as, for example, an entire theme park the possibility of two tags having the same ID is more likely. If a location is highly specific, such as “Cash Register X, in store Y, at resort W, at theme park Z” this is much less likely happen. In one embodiment, location IDs are divided by regions. For example, there may be 2,000,000 IDs for each region (i.e. state or city).
[0019] In alternate embodiments, RFID tag 70 may be a read only tag, a WORM (write once, read many) tag, or a read/write tag. As is known in the art, read only RFID tags contain unique information that cannot be changed. WORM tags may be encoded a single time and then locked into a read only state. Read/write tags allow for unlimited updating and transfer of information to the tag. RFID tag 70 may take the form of a thin flexible label or ticket that may be affixed to an object, such as cup 105 . Alternatively, as shown in FIG. 5 b , tag 70 may be embedded in a card or integrated into an object. The tag 70 may also be molded directly into cup 105 .
[0020] Tag 70 may also be an electronic article surveillance (EAS) tag. In general, the EAS tag would be attached to a disposable or non-disposable cup that will be filled at beverage dispensing system 2 only one time. Initially, the EAS tag will have a closed circuit/gate, rendering the tag active. When the EAS tag is placed over an EAS/RF antenna, the closed circuit is broken and the tag is deactivated. The EAS/RF antenna will indicate to controller 60 that an EAS tag has been deactivated and controller 60 will signal the dispensing heads to open until a predetermined number of ounces have been dispensed. The dispensing of a beverage occurs in a manner similar to that described below in connection with an RFID tag. Once the EAS tag's circuit is broken and the tag is deactivated, the tag cannot be reused. If a deactivated tag (broken circuit) is placed on the antenna again it will not send a signal to the dispensing machine to make the dispensing heads active, since the antenna only sends a signal to activate the dispensing heads after a EAS tag's circuit is broken. In one embodiment the EAS tag can be reactivated by purchasing a refill. However, each reactivation only allows for a single transaction since each reading of the EAS tag by the antenna effectively deactivates the tag.
[0021] It should be recognized that the embodiments described are not meant to be limiting and Tag 70 may include any read-only, read-write or a combination of read-only and read-write tags that are known in the art. For example Tag 70 could be any one of programmable identification tags, EEPROMs, smart cards, magnetic strip cards, resonance circuits, or optical cards. The beverage system 2 helps to control the theft of beverages dispensed into containers not associated with dispensing system 2 , calculate the exact amount of ounces and the brand being poured into each cup (e.g., based volumetric flow rate and time) to allow the customer to determine the average ounces poured per cup per program (e.g., for price validation), manage inventory, and determine where the cups were purchased. These and other features will help retailers bill offsite locations for beverages poured at their locations. For example, a first retailer may receive money for the sale of an RFID mug and associated refills, but the customer goes to a second retailer to dispense the refill. Beverage dispensing system 2 allows the second retailer to bill the first retailer for the expense of the refill.
[0022] In one embodiment, a cash register includes RFID hardware capable of reading and writing information to and from RFID tag 70 . RFID hardware at cash register may send information (location, promotion code, date, etc.) to RFID tag 70 . After cup 105 with RFID tag 70 is purchased, the consumer may take cup 105 to dispensing system 2 to dispense a beverage. In one embodiment, antenna 68 is constantly looking for an RFID tag in the reading field. As discussed above, a single antenna (read station) that spans across one or more than one dispensing heads is used. The antenna can be placed in any suitable location, e.g., on the back panel above the drip pan and in front of the drip pan, or in the drip tray. Alternatively, multiple antennas may be used. Once the antenna finds a valid RFID tag it will open all of the heads so a beverage can be dispensed. Once a particular head is activated to dispense a beverage, the other heads will shut down.
[0023] Alternatively, the controller may notify the antenna to search into the reading field to validate a cup only after a lever or push button (on/off switch) is depressed in an attempt to dispense a beverage. In another embodiment, antenna 68 will not read into the reading field to validate a cup until after an infrared proximity sensor(s) sees that a cup is under the dispensing head. The sensor will then notify the dispensing machine to read the field for information. In one embodiment, a cup is time stamped by the host controller board/PCB as it enters the reading field. If multiple cups enter the field, each cup will be time stamped and read for information individually. The first cup that touches a lever has the flow button pushed or is read by the infrared proximity sensor will be “classified” as the first cup into the reading field, and will be matched up with the information received from the cup (RFID tag) that was time stamped first.
[0024] If a consumer attempts to dispense multiple beverages into the same cup during a singe transaction the total ounces of a beverage being poured into each cup is determined using time and flow rate based calculations. As described above, a cup may be time stamped when it enters the reading field or the RFID antenna may be instructed to search for an RFID tag after a cup is sensed by an IR sensor or when a button or lever is depressed. Each of these techniques assists dispensing machine 2 in identifying where cup 105 is located in the reading field. Therefore, time and flow rate based calculations may be performed. Reader 65 and antenna 68 have the ability to locate a tag within approximately a 1 foot grid. However, readers 65 and antennas 68 having a read field as small as inches from antenna 68 may be used.
[0025] Antenna 68 and reader 65 may be retroactively attached to beverage dispensing system 2 . For example, antenna can be plugged into a harness that connects to controller 60 . Controller 60 includes another harness that has a relay switch for each dispensing head. This relay switch (harness) is coupled to each dispensing head. The switch will be always or at least most of the time so that the head will be inactive and inoperable until the gate is closed. The harness that goes to the dispensing heads may also be used, if infrared proximity sensors are not being used, to notify the dispensing system that a cup is under a certain head. If an infrared proximity sensor is used to determine if a cup is under a dispensing head, a separate harness will be used. The harness will go from the host controller board/PCB to the infrared proximity sensors located on the antenna or dispensing machine.
[0026] In one embodiment, a refillable cup having an RFID tag is purchased at a cash register or other transaction area. At the time of purchase information is written to the RFID tag using the write antenna/reader at the register. For example, a customer may purchase a refillable cup and 5 refills of 16 ounces each. The number of refills and ounces per refill is written onto the RFID tag when the cup is purchased. When the customer approaches the beverage dispensing system 2 , cup is placed under the dispensing head and the position of the cup is located, e.g., by an infrared proximity sensor, a lever, or an on/off push button on the dispensing head. When a cup is located, read antenna 72 will read the information on the cup's RFID tag. RFID tag may be prompted by CPU to search for tag 70 or antenna 68 may be constantly searching for an RFID tag. The collected information is used to verify the cups validity. If the cup is valid, a signal is sent from CPU 60 to a dispensing head. The signal may be sent through a harness having a relay switch that is coupled to the dispensing head. The valid signal will close the relay switch gate allowing the beverage to pour. Alternatively, the power to each head is turned on and off. When the power is on the dispensing head will pour, when the power is off the dispensing head will not pour. The head will stop pouring after the cup is moved away from the proximity sensor, the pour lever is released, the on/off push button is released, or the allotted ounce capacity for the cup has been reached.
[0027] FIG. 6 illustrates one embodiment of the basic flow of a customer's interaction with beverage dispensing system 2 . As indicated in block 150 , when a customer approaches system 2 a proximity sensor identifies that a person or object has entered the vicinity of system 2 . For example, the proximity sensor may detect a person or object approximately 2 feet away from the sensor. In one embodiment the proximity sensor is located in the center of the drip tray, such as on the RFID antenna housing, which may be manufactured in plastic, in a horizontal configuration. A signal is then sent from the second proximity sensor to CPU 60 which activates display screen 20 , as indicated in block 155 . Display screen 20 will show an image of a customer placing a cup on or near RFID antenna 68 . The Read/write RFID antenna 68 may include a second proximity sensor, in a vertical configuration, so when a cup is placed on the RFID antenna housing the proximity sensor will read that a cup is in the read/write antenna location. At this point, RF reader 73 will search, either automatically or by command from CPU 60 , for an RFID tag 70 . If an RFID tag is detected by reader 73 , CPU 60 will signal user interface 19 to display a refillable cup screen, as indicated in block 170 . If an RFID tag is not identified, the touch sensor screen will display a disposable cup screen, as indicated in block 175 . The disposable and the refillable screens will show pictures of the cups that are available for refill promotions or disposable cups, respectively, as shown by block 185 . The customer will select and touch a picture of the cup they want to purchase on the touch sensor screen. After the customer has selected the ounce size cup they want to purchase, the screen will go to the payment display screen with the following payment options: Debit card, Credit card, or Paid at the Register verification (see block 190 ). The customer may then select the desired payment option from the screen display.
[0028] If the customer selects the debit card or credit card options, the screen will prompt the following, or similar, questions: How many cups do you wan to purchase?; How many refills do you want to purchase? The customer will select an appropriate response, for example, using a keypad on the screen, images on the screen or by a separate keypad. After these questions are answered the screen will display an image or video of a customer swiping a debit or credit card. The CPU will then prompt the screen to display a request of a customer's pin number or zip code and amount verification, before the transaction is processed. The transaction will then be processed as a normal debit or credit card purchase through a standard phone line or internet. Display screen 20 may also show commercials or other audiovisual presentations when the dispensing of a beverage begins.
[0029] If the customer has prepaid at the cash register, a verification code would have been printed at the time of purchase. The code will be generated through the use of the internal calendar and clock. Therefore, the code represents the time the cup is purchased. When prompted by the screen, the customer would select the “Paid at Register” option. A new screen display will then ask the customer to enter the verification code, which may be a 4-digit numerical code. CPU 60 , by way of controller software, converts the code back into time of purchase data. If the time of purchase is within a predetermined time, such as 1 hour from the time of purchase, dispensing is allowed. The code also conveys information relating to the size of the cup.
[0030] Following payment by a credit/debit card or validation of the code, the dispensing heads will be activated as the dispensing heads are activated as indicated by block 210 of FIG. 6 . At this time, the screen will instruct the customer to start pouring his/her beverage. This can be accomplished with a tutorial video or text display.
[0031] If a confirmed pre-paid RFID Tag was identified at the antenna, as described above, the CPU will prompt the RFID tag reader to read the RFID tag for information as indicated by block 195 . For example, the Cup/RFID tag ISO number or custom number is read from the tag. This allows retailers to use the individual ID number to track inventory of the cups and determine how many ounces have been poured into each ISO numbered or custom numbered cup. The reader may also read information relating to the location where the cup and RFID tag were purchased. In addition, the number of remaining refills or time left on the RFID tag (in the case where the tag is valid for a predetermined time period, e.g. one day). This information is used by the CPU to determine if the tag is valid. The validity of the RFID tag will vary with each promotion and may be based on a calendar date or the number of refills. For example, the tag may include a calendar date/time at which it will be invalidated or a counter for determining when the maximum number of refills has been reached. The tag may also include information specific to the cup size, such as the designated pouring ounces to reach the capacity of the cup.
[0032] Following the reading of the information on the tag and verification of the validity of the tag, the CPU will reduce the number of pre-paid refills available on the RFID tag, assuming such information is stored on the tag. More specifically, RFID reader will read the number of refills available and send a signal to the CPU. The CPU will then reduce that number by one refill. The new counter number will then be written back onto the RFID tag, making the new number 1 less than the number that was originally read, as indicated by block 200 . Information is written back the tag and confirmed before the beverage is poured into the cup in order to avoid inconsistent writing and confirming to the tag. Ice/liquid being poured into the cup may manipulate the RF field. The new counter number will be stored on the cups RFID tag and possibly the CPU. The information stored on the CPU may be used by the retailer to more accurately calculate inventory projections. In another embodiment, such as with HF tags, the HF tag is read and written to when it is placed on the antenna in one step. The read/write field of the HF tag is approximately 2 inches; therefore, the tag must remain with in the two inch field until information is written to the tag. Following the writing of the tag, a 30 second time window will begin to allow the customer to dispense the beverage. Following the writing of information back to tag 70 and the initiation of dispensing, the dispensing heads are activated as indicated by block 210 of FIG. 6 .
[0033] In one embodiment, a read-only antenna is used in connection with dispensing system 2 . The read-only antenna reads the tag's ISO number and sends the number or other relevant information to a central computer system via internet or a phone line. The central computer system validates the information on the cup, subtracting the refill counter number by 1, and sending validation information back to dispensing system 2 . The computer system is capable of storing numerous counter numbers and processing transactions from multiple locations, in many different states, at the same time.
[0034] After the counter number is written to the RFID tag on the cup or the transaction is otherwise validated, the CPU will activate each dispensing head by supplying electrical power or the like. Therefore, all of the dispensing heads are active until a particular activator (lever, button, etc.) is engaged. Following the engagement of an activator, the remaining dispensing heads will be turned “off”. The CPU will then begin counting the ounces being dispensed. The number of ounces may be determined by counting the seconds the beverage is being dispensed. For example, a typical cold fountain machine dispenses 3.5 ounces per second and a typical hot/coffee dispensing machine dispenses 1.8 ounces per second. Therefore, if a cold fountain machine refill is 16 ounces the CPU will begin counting the seconds and shut off the dispensing head after approximately 4.5 second.
[0035] CPU will continue to count the ounces dispensed until the designated maximum capacity (beverage and ice) of the cup has been poured; therefore, a customer will have the ability to switch the type of beverage being dispensed before the maximum amount has been dispensed. If the actuator is disengaged, such as a cup being pulled away from a lever actuator, the dispensing of the beverage will stop. The CPU will then open all of the dispensing heads until another actuator is engaged. The remaining heads will then be deactivated once again. However, if an actuator is not engaged within a predetermined number of seconds, the CPU will stop the transaction and close the dispensing heads. In addition, if the proximity sensor no longer detects a person or object within the vicinity of the dispensing system, indicating that the customer has left the area, the CPU will close the dispensing heads. For example, if a person or object is not detected for ten (10) seconds the heads will shut down. The predetermined time limit for sensing a person may be shorter than the time limit for not engaging an actuator. Therefore, if a person leaves the area the heads will shut down without much delay, but if a customer is in front of the machine making a decision the machine will allow for a longer delay.
[0036] Beverage dispensing system 2 allows for one or more users to dispense beverages simultaneously. However, if more than one actuator per validated code/RFID tag is engaged, all dispensing heads will be deactivated. Dispensing will resume when the correct number of actuators are engaged. The dispensing system may have a maximum user limit, such as two users at a time. For example, when a first customer enters the vicinity of beverage dispenser 2 (in the case of an antenna that automatically reads) or is placed on antenna (in the case where antenna is prompted to read as a result of a proximity sensor) that customer's RFID tag is read and the ISO number on the tag is registered by beverage dispensing system 2 as user 1 . Beverage dispensing system 2 assumes that the first actuator to be engaged is engaged by user 1 . In the case where the antenna automatically searches for an RFID tag, the antenna reads every 1/10 of a second; therefore, the sequence of users will be very accurate. When a second user enters the antenna's read field, the ISO number on the tag will be read and stored as user 2 . The second actuator that is engaged will be assumed to be user 2 . If one of the users disengages the actuator, CPU 60 it will know which user was using that designated dispensing head. The next actuator that is engaged will be assumed to be engaged by the user that pulled away from the previous dispensing head. As described above, CPU calculates the number of ounces poured into each cup; therefore, if the ounce capacity is not reached, the user will be able to continue pouring the same brand or a different brand until the ounce capacity is met.
[0037] In an alternate embodiment, half of the dispensing heads remain activated when a valid RFID tag is detected and an actuator is engaged. For example, if a first tag is validated, all of the dispensing heads are opened. When a customer (with the first tag) engages an actuator, half of the dispensing heads are closed. With reference to FIG. 1 , if actuator 26 is engaged, dispensing heads associated with valves 15 - 18 will remain open and dispensing heads associated with valves 19 - 23 will close. If a second tag is validated while the first customer is dispensing a beverage, the remaining dispensing heads 19 - 23 will be activated. In another embodiment, all dispensing heads will open when a first tag is validated. The heads will close after a lever is pushed. All of the heads will reopen if a second tag is validated. They will then close after a second lever is pushed.
[0038] After the transaction is complete additional information may be written onto tag 74 . This information may include the type of beverage poured, ounces poured, and time of pour. The information is stored under each individual ISO number in the CPU and may be sent to a centralized computer through the use of the internet, phone lines, USB port/memory stick, or an Active RFID chip. This transfer of information may occur at a predetermined time and/or day. The centralized computer will collect and compile the data and manipulate it into useful data, such as the average ounces poured into refillable and disposable cups. The centralized computer is also capable of calculating or determining the true costs between refillable and disposable cups, ounces poured into each cup, the true cost per customer, the brand poured into each cup (i.e. ounces of each brand). This information is useful for tracking the inventory of each brand. Therefore, the manager can be notified and/or inventory can be automatically ordered using an inventory system. The centralized computer system may also identify and report the locations where the RFID tagged cups were refilled, thus allowing retailers to cross-bill to recover their true costs and profits.
[0039] The system may be completely software driven so that promotions are endless. For example, to increase more frequent visits at a store with a cup refill program you have to create loyalty. A way to achieve this is to give cups (and their owners) reward points for using their cups at the store chain. The more times people pour at a certain store chain, the more reward points they receive. Another example is that a customer can be given 5 free cups for every 10 purchased. The customer does not have to worry about a ticket, and the store can actually see true numbers for the number of pours a person actually pours for this type of promotion.
[0040] RFID tag, which is coupled to cup 105 and in communication with a cash register system (not shown) and/or beverage dispenser 40 . The register system 306 and dispenser 40 are in communication with controller 60 . The register system includes a transmitter that communicates with a register. The register could include an integrated transmitter. Alternatively, the system could use a separate transmitter which does not communicate with the register and, for example, includes a separate input device, such as a touch pad. In one embodiment, the register is a cash register that is used to determine the cost of the customer's order. The transmitter can be in communication with the register so that data is exchanged between RFID tag 70 and register when the customer buys a drink and receives the cup 105 .
[0041] The CPU 60 can be in communication with the register system and beverage dispenser 40 . The register system and beverage dispenser 40 have transmitters, and are in communication with controller 60 . For example, controller 60 can receive signals from the transmitter and then can communicate with the beverage dispenser 40 to cause the dispenser 40 to dispense or not dispense liquid when one of actuators 26 - 33 is moved. In one embodiment, when the customer buys a drink, the register sends a signal based on data from the transmitter. Controller 60 can communicate with the transmitter to control the liquid dispensed by dispenser 40 . Alternatively, controller 60 can let the restaurant know, for example, through a signal to the register system and/or a display, that someone is seeking an unauthorized refill. Preferably, the transmitter is proximate to dispenser 40 to ensure proper communication between the transmitter and RFID tag 70 . Although not illustrated, controller 60 can be at various locations on the vendor' premises. For example, controller 60 can be within housing 5 of the dispenser 40 or underneath a counter, preferably not accessible to the public. Of course, the vendor can be a drink seller, such as a fast food restaurant, food court, a concession stand (e.g., at an amusement park), cafeteria, or the like.
[0042] In one embodiment, beverage dispensing system 2 is coupled to a food preparation area such that a customer can order food items without the need to approach a traditional cash register. Screen 20 may include a “Menu” selection option. This will allow a customer to select menu items for purchase at dispensing system 2 by making a sequence of choices, which will be prompted by screen 20 . Once the desired menu items have been selected, the customer may pay for the items using debit/credit card apparatus #, which is coupled to dispensing system 2 . Following the selection and payment of menu items, the order is sent to monitors in a food preparation area (not shown) by wires or other suitable communication means, such as internet or cellular technology. The monitors in the food preparation area will display the order made at beverage dispensing system 2 so that the appropriate personnel can promptly prepare the order. Software for controlling the menu functions of the beverage dispensing system 2 may be coupled to a central cash register within a store via wires or other suitable means. A record of the transaction can be sent to the central cash register for record keeping and inventory purposes.
[0043] With respect to the above description, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. While particular forms of the invention have been described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims. | A beverage dispensing system comprising a dispensing device including a dispensing valve for dispensing a beverage, an actuator for initiating the dispensing of said beverage through said valve, a display screen having a user interface being coupled to said dispensing device, wireless communication electronics coupled to said beverage dispensing system and adapted to communicate with a wireless transponder and a controller functionally connected to said at least one dispensing valve, said display screen and said wireless communication electronics. | 0 |
RELATED APPLICATION
The present application is related to U.S. provisional patent application Ser. No. 61/734,519, filed Dec. 7, 2012, by SATOH et al., which is included by reference herein and for which benefit of the priority date is hereby claimed.
FIELD OF THE INVENTION
The present invention relates to the techniques for fabricating arrays of magnetoresistive random access memory (MRAM) cells such as those including magnetic tunnel junctions (MTJ) memory elements on wafers. The invention relates more particularly to etching processes for fabricating magnetic tunnel junction (MTJ) stacks and the bottom electrode.
BACKGROUND OF THE INVENTION
FIG. 1 illustrates a cross sectional view of a selected stage in the prior art fabrication process of MTJ MRAM arrays after MTJ etching. A memory element of MRAM typically includes of a bottom electrode, a MTJ (Magnetic Tunnel Junction) and a top electrode (TE) 6 . The top electrode layer 6 can be a single layer metal or multi-layer stack consisting of metal and dielectric materials. The MTJ is formed with a barrier layer 4 such as MgO sandwiched between a top magnetic layer 5 and a bottom magnetic layer 3 . At the stage shown in FIG. 1 the MTJ layers have been etched, but the bottom electrode layer 2 has not been etched. The bottom electrode layer 2 has been deposited over the typical CMOS control structures 1 .
Magnetoresistive random access memory (MRAM) cells including magnetic tunnel junctions (MTJ) memory elements can be designed for in-plane or perpendicular magnetization of the MTJ layer structure with respect to the film surface. One of the magnetic layers is designed to serve as a free magnetic layer while the other one has a fixed magnetization direction. The resistivity of the whole MTJ layer stack changes when the magnetization of the free layer changes direction relative to that of the fixed layer, exhibiting a low resistance state when the magnetization orientation of the two ferromagnetic layers is substantially parallel and a high resistance when they are anti-parallel. Therefore, the cells have two stable states that allow the cells to serve as non-volatile memory elements.
The MRAM cells in an array on a chip are connected by metal word and bit lines. Each memory cell is connected to a word line and a bit line. The word lines connect rows of cells, and bit lines connect columns of cells. Typically CMOS structures 1 include a selection transistor which is electrically connected to the MTJ stack through the top or bottom metal contacts. The direction of the current flow is between top and bottom metal electrodes.
FIG. 1 shows a selected stage in the fabrication process after MTJ etching using a conventional mask etching process steps such as lithography and reactive ion etching (RIE). MTJ etching chemistry may create surface damage 7 on sidewall with a depth δ. It should be removed in the next step. The removal process is strongly dependent on the sidewall angle α.
Ion Beam Etching (IBE) has been widely used in various industries for patterning thin films. It is convenient to etch hard materials with chemical etching processes such as RIE (Reactive Ion Etch). It is, however, difficult to find a hard mask material with enough selectivity for use with RIE. Re-deposition of etched material on the sidewall is also a serious concern, because it can make it the device inoperable by forming an electrical short across the barrier layer.
FIG. 2 illustrates a cross sectional view of a selected stage in the prior art fabrication process of bottom electrode etching with normal incidence. A conventional bottom electrode etching process often uses chemistry free etching using Ar, Kr and so on in which the etching products are not volatile. Re-deposition from the top electrode and/or the bottom electrode is a serious concern as illustrated in FIG. 2 . When a conductive material is re-deposited on the MTJ sidewall at the barrier layer, the top and bottom magnetic layers are shorted. The re-deposition depends on sidewall slope.
Etching and re-deposition occur simultaneously. When the deposition rate is larger than the etching rate, re-deposition material accumulates on the sidewall. When the etching rate is higher, the sidewall is cleaned up. In vertical directional etching with etch rate ER, the lateral etch component is estimated by (ER/Tan α), where α is the slope of the sidewall. Shallow slope is helpful for preventing the re-deposition. However, it is not desirable for controlling the MTJ size and its uniformity for scalability. This vertical etching method removes top electrode thickness by (δ×Tan α) in order to remove thickness δ of the damaged sidewall layer 7 . This amount of top electrode thickness loss is not desirable and would make downstream interconnect process difficult.
The higher or more vertical the slope, the more susceptible it is to re-deposition since the lateral component of etch rate in directional etching ambient such as IBE is, in general, less than the vertical component. Using a tilted incident ion beam increases the etching rate of re-reposition material and thus reduces the net re-deposition. It is not desirable to expose MTJ sidewall to atmosphere for wet cleaning. IBE can advantageously clean the sidewall without exposing to atmosphere.
However, IBE is a purely physical etching process, so the etch rate does not vary greatly among various materials. In other words, IBE material selectivity is low. Specifically, IBE etching selectivity of a hard mask layer versus magnetic materials is not as desirable as that of a chemical etch process such as RIE. A very thick hard mask is therefore required for IBE etching through MTJ stack and BE layers. On the other hand, MTJ components are sensitive to being degraded by the chemical etching ambient, which often degrades TMR (tunnel magneto-resistance). It has been found that the etched surface of MTJ, including the sidewall edge, is damaged in plasma ambient. The damaged depth is estimated to be on the order of several nanometers (nm) from the surface. Tilted angle IBE works to remove the damaged layer. IBE is effective to clean sidewalls.
Another issue is the process sequence and complexity. In some fabrication methods, the main body of MTJ stack and bottom electrode are defined separately using two different photo-masks. Specifically, field MRAM requires the MTJ stack and bottom electrode to be patterned separately. However, separate patterning is not mandatory for STT (Spin Transfer Torque) MRAM. While it is less challenging to fabricate the device from etch point of view, there is a trade-off with process complexity, manufacturing cost, as well as extendibility to high density. In addition to the photo-mask required to pattern MTJ stack, an extra mask is needed to define bottom electrode, which complicates the process flow due to required planarization after each photo processing step, overlay margin tolerance, etc. Also a small cell area cannot be achieved with BE size larger than MTJ size, so this limits extendibility.
SUMMARY OF THE INVENTION
Embodiments of the invention include manufacturing methods using Ion Beam Etching (IBE) to fabricate a memory element for an MRAM cell. In embodiments the top electrode and MTJ main body are etched with one mask using reactive etching such as RIE or magnetized inductively coupled plasma (MICP) for improved selectivity, then the bottom electrode is etched using IBE as specified in various embodiments which include selection of incident angles, wafer rotational rate profiles and optional passivation layer deposited prior to the IBE. The IBE according to the invention etches the bottom electrode without the need for an additional mask by using the layer stack created by the first etching phase as the mask. This makes the bottom electrode self-aligned to MTJ. The IBE also achieves MTJ sidewall cleaning without the need for an additional step.
As discussed above there is benefit in defining the MTJ and bottom electrode with one single mask. One photo process and related process such as planarization, cleaning and so on can be eliminated. Since overlay margin is not necessary, cell size can be reduced, which is key for high density arrays. The invention solves the problem of conductive material re-deposition on MTJ sidewall and/or damaging with chemical reaction during MTJ etch and bottom electrode etching that has been preventing the implementation of the one mask process. Embodiments of the invention use an IBE process with adjustable incidence angle to enable sidewall cleaning and bottom electrode removal simultaneously. Several embodiments using IBE will be described.
First set of embodiments: After the MTJ is patterned by a first etching process, IBE is used for bottom electrode etching. This IBE step is to remove the bottom electrode and clean the sidewall simultaneously. The IBE process can use single incident angle or the IBE process can be split into two steps. The first step removes the exposed bottom electrode layer with a first incident angle selected for faster etch rate, and then the second step uses a second incident angle selected to clean the sidewall. More generally, the IBE process can be split into N steps, where N>2 and the incidence angle for each step can be adjusted independently for each step. The MTJ etch can be by RIE. The RIE can include plasma etching using as inert gas such as Ar. The MTJ etch can also be plasma etching only using pure inert gas like Ar, to reduce the chemical damage on MTJ stack.
In an alternative embodiment the MTJ etch starts with RIE, and RIE stops prior to the barrier layer. The remaining MTJ stack and the bottom electrode are etched by IBE. This prevents MTJ damage by the RIE chemistry.
Optionally the IBE etch gas can be something other than Ar, such as Kr, Xe, etc.
Second set of embodiments: MTJ sidewall is protected by depositing dielectric material after MTJ etching and prior to IBE bottom electrode etching. This prevents the barrier layer from incurring plasma damage. In some embodiments, an oxygen free dielectric material is preferred.
Third set of embodiments: During IBE etch, MTJ CD (Critical Dimension) is self-compensated with selected incident angle for the IBE. The etch rate of IBE depends on the incident angle. One source of MTJ CD variation is due to sidewall slope angle variation. CD can be adjusted by optimizing IBE angles according to the invention.
Fourth set of embodiments: These embodiments apply a variable rotation speed profile to the wafer during IBE etch to achieve differential etching of the MTJs at selected angular positions. The rotation speed is varied at different angular positions in the wafer's rotation cycle to increase or decrease the effective etch time so that different amounts of material are removed by the IBE etch from the MTJ sidewall. Lower rotation speed gives a higher material removal rate. The rotation speed profile can be used to correct for differential redeposition and etching rates for the long and short axes of the MTJ pillars. The rotation speed profile can also be used to modify the aspect ratio of the MTJ pillars.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 illustrates a cross sectional view of a selected stage in the prior art fabrication process of MTJ arrays after MTJ etching.
FIG. 2 illustrates a cross sectional view of a selected stage in the prior art fabrication process of bottom electrode etching with normal incidence.
FIG. 3 illustrates a cross sectional view of bottom electrode etch with tilted IBE angle incident according to a first embodiment the invention.
FIGS. 4A and 4B illustrate a cross sectional view of first and second steps of an alternative of the first embodiment.
FIG. 5 illustrates a cross sectional view of alternative embodiment that includes deposition of a passivation layer over the MTJ stack prior to bottom electrode etching.
FIG. 6 illustrates a cross sectional view of an alternative embodiment using two stage MTJ etching using RIE down to the barrier layer, then IBE.
FIG. 7 is a chart showing IBE etch rate as a function of incident angle.
FIG. 8 illustrates a cross sectional view of an embodiment of the invention using IBE angle to control the slope profile of the MTJ.
FIG. 9A is a graph illustrating systematic rotational speed variation for the wafer stage during IBE in an embodiment of the invention.
FIG. 9B illustrates a top view of embodiment of the invention using systematic rotational speed variation for the wafer stage during IBE differentially affect IBE etching for the long and short axes of the MTJs.
DETAILED DESCRIPTION OF THE INVENTION
In the following description of the embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration of the specific embodiments in which the invention may be practiced. It should be noted that the figures discussed herein are not drawn to scale and do not indicate actual or relative sizes. Any hatching in the figures is used to distinguish layers and does not represent the type of material used. A plurality of arrays of magnetoresistive random access memory (MRAM) cells are typically fabricated simultaneously on a single wafer. The figures and description herein reference only one or two cells of the plurality of cells that will be typically be fabricated simultaneously on a single wafer.
FIG. 3 illustrates a cross sectional view of bottom electrode etch with tilted IBE angle incident according to a first embodiment the invention. The IBE angle incident etching begins from the stage of the process shown in FIG. 1 . The previously etching MTJ stacks in effect provide the self-aligned mask for the bottom electrode IBE. The tilted IBE and rotation of the wafer according to a first embodiment of the invention simultaneously etching the exposed bottom electrode layer and cleans the sidewalls of any surface damage caused during the MTJ etching phase. In this embodiment a single fixed IBE angle is selected based on experiment that will remove the exposed bottom electrode layer and clean the sidewalls. The rotation of the wafer can be selected as a uniform rate in this embodiment. In alternative embodiments described below the rotation rate can be systematically varied to achieve certain desirable results.
Tilted incidence angle and wafer rotation provided by IBE are used in embodiments of the invention to address the re-deposition and damage issues described above. Since reactive ion etching (including inductively coupled plasma (ICP) etching) utilizes self-bias generated between parallel plates, the incidence is inherently perpendicular to the wafer surface. Therefore, it cannot be tilted. On the other hand, in the IBE system, a wafer mounting plate and the acceleration field can be manipulated independently. The beam incident angle θ can be tilted as shown in FIG. 3 . Since incident angle is defined with reference to a line perpendicular to the plane of the wafer, the term “normal incidence” refers to 0 degree incident angle. Incident angles closer to 0 degree incident angle will be called “low” angles. Similarly as used herein a “higher” angle of incidence refers to a higher angle θ.
In addition, the wafer is mechanically rotated (as illustrated by the curved arrow) for etching uniformity. The tilted IBE is conventionally applied to sidewall cleaning. In embodiments of the invention, it is also simultaneously applied to bottom electrode 2 ′ etching. This process has the advantage of not needing an extra mask other than that required for MTJ etch. It simplifies the process flow and eliminates cell area penalty due to overlay because the bottom electrode 2 ′ is defined by a self-aligned process.
An alternative of the first embodiment separates the IBE bottom electrode etching into 2 steps as shown in FIGS. 4A & 4B . In FIG. 4A the 1 st step is designed to remove the exposed bottom electrode material with a first angle which is preferably a low angle of incidence (e.g. close to normal) selected to efficiently remove the unneeded bottom electrode material. In some cases, a higher etching angle is effective to remove the bottom electrode but is susceptible to re-deposition. As shown in FIG. 4B , the 2 nd step is to clean the sidewall with a second incident angle, higher than the first angle.
Variations of the first embodiment include etching the MTJ stack with processes with reduced chemical damage including ICP using inert gas such as Ar or Kr, or a mixture of Ar or Kr with other gases such as CH3OH, CO, NH3, etc. This step is followed by the bottom electrode etching with angle IBE for sidewall re-deposition cleaning.
Etch rate of RIE including MICP using inert gas like as Ar or Kr, or pure plasma etching using inert gas like Ar or Kr, is faster than IBE. Thus, the MTJ stack can be relieved from chemical damage of conventional RIE, and achieve better throughput than using pure IBE to etch both MTJ stack and bottom electrode.
A second embodiment of the invention illustrated in FIG. 5 adds to the first embodiment and its alternatives by including MTJ sidewall protection by depositing passivation layer 8 over the etched MTJ layer stacks and the unetched bottom electrode layer 2 prior to commencing the bottom electrode etching process. The passivation layer 8 can be a material such as a nitride. The passivation layer 8 protects the barrier layer from re-deposition during the bottom electrode IBE with incident angles normal or close to normal. The passivation layer 8 in this embodiment avoids the barrier layer exposed to air when vacuum is broken in some embodiments. The passivation layer 8 is consumed during the IBE process.
FIG. 6 illustrates an alternative embodiment in which the MTJ etching is separated into two stages. The first stage proceeds with RIE etching until the barrier layer 4 ′ is exposed as shown in FIG. 6 . At this point angled IBE etching is commenced as shown in FIG. 6 . Remaining MTJ layers in the stack are etched using low angle IBE, i.e. close to normal incidence. The bottom electrode is then etched either by the one-step high angle IBE process or the 2-step IBE process with different incident angles as described above. This alternative embodiment prevents damaging of the barrier layer and bottom magnetic layer with RIE chemistry.
The third embodiment of the invention includes self-adjustment of MTJ CD (Critical Dimension) with angled IBE. Etch rate of IBE depends on the specific materials as well as the incident angle as shown in FIG. 7 . In this example the etch rate is highest at an incident angle of 50 degrees. The etch rate can be separated into vertical and horizontal components which vary with the incident angle of IBE. By varying the incident angle (a 1 , a 2 , a 3 ), the bottom slope of MTJ can be changed as shown in FIG. 8 due to different etch rates. The higher angles, such a 3 , result in greater etching of the lower magnetic layer 3 . The lowest angles, such a 1 in this example, result in relatively less etching of the lower magnetic layer 3 . By selecting an optimal angle, the slope of the bottom of the MTJ can be formed as steep as desired. Control of the slope of the bottom of the MTJ is advantageous for control the CD. A steep side wall makes it easier to control the CD.
FIG. 8 illustrates that the choice of IBE angle affect the slope of the bottom of the MTJ. In an embodiment, the IBE incident angle can be selected as one fixed angle optimized based on experiments. However, because the MTJ is a multi-layered film stack and each film can have a unique IBE angle dependence, using more than one angle of incident may work well.
In the foregoing the ion beam incident angle was the focus of the embodiment. In the fourth embodiment of the invention, the direction of the ion beam as viewed in a top view of the wafer is discussed. The fourth embodiment of the invention, see FIGS. 9A , 9 B, uses variable rotation speed of IBE stage on which the wafer 10 is mounted during the IBE phase. The ion beam direction remains fixed while the stage with the wafer rotates. The MTJs 11 on the wafer are formed with an oval-shape with short axis A and long axis B oriented in the same direction. As the wafer rotates the ion beam direction in relation to the long and short axis of the MTJs sweeps through 360 degrees cycles.
Re-deposition on sidewall of the oval-shaped MTJ 11 is different between short axis A and long axis B. The sidewall slope along long axis is smaller than that of short axis. The amount of re-deposition is more on along the short axis than the long axis. To correct for this difference, the rotation speed in this embodiment is selected to be lower when the shorter A axis is aligned with the IBE direction than when longer B axis is aligned with the IBE direction as shown in FIG. 9B . Each axis will be aligned with the IBE direction twice during a rotation.
As illustrated in FIG. 9A , the rotational speed is systematically changed during each 360 degree rotation. Various profiles or algorithms can be used to change the rotational speed during the cycle and the optimal profile should be determined empirically for a particular IBE system, a given MTJ aspect ratio, the shadowing effects that occur, etc. The B axis direction is more susceptible to shadowing. For example, the rate could be varied on a sinusoidal curve or step changes could be made at selected points. In the particular example of FIG. 9A , the rotational speed is changed on a linear, ramp profile. The rotational speed reaches a maximum at the two angles (90 & 270 degrees) where the B axis is aligned with the IBE direction. The rotational speed reaches a minimum at the two angles (180 & 360 degrees) where the A axis is aligned with the IBE direction.
Another potentially beneficial effect that can optionally be obtained by systematically varying the rotation speed through each rotation is that aspect ratio (AR) of MTJ elements can be adjusted. By differentially slowing the rotation rate in relation to a selected axis, which can be the long or short axis, the etch rate is increased for that axis. For example, if the long axis of the MTJs needs to be shortened to change the AR, then systematically slowing the rotation rate when the ion beam is parallel will cause the ratio of the long axis length to short axis length to decrease.
Although the present invention has been described in terms of specific embodiments, it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art. | Fabrication methods using Ion Beam Etching (IBE) for MRAM cell memory elements are described. In embodiments of the invention the top electrode and MTJ main body are etched with one mask using reactive etching such as RIE or magnetized inductively coupled plasma (MICP) for improved selectivity, then the bottom electrode is etched using IBE as specified in various alternative embodiments which include selection of incident angles, wafer rotational rate profiles and optional passivation layer deposited prior to the IBE. The IBE according to the invention etches the bottom electrode without the need for an additional mask by using the layer stack created by the first etching phase as the mask. This makes the bottom electrode self-aligned to MTJ. The IBE also achieves MTJ sidewall cleaning without the need for an additional step. | 7 |
[0001] The instant invention relates to liquid compositions comprising derivatives of diaminostilbene, binders and divalent metal salts for the optical brightening of substrates suitable for high quality ink jet printing.
BACKGROUND OF THE INVENTION
[0002] Ink jet printing has in recent years become a very important means for recording data and images onto a paper sheet. Low costs, easy production of multicolour images and relatively high speed are some of the advantages of this technology. Ink jet printing does however place great demands on the substrate in order to meet the requirements of short drying time, high print density and sharpness, and reduced colour-to-colour bleed. Furthermore, the substrate should have a high brightness. Plain papers for example are poor at absorbing the water-based anionic dyes or pigments used in ink jet printing; the ink remains for a considerable time on the surface of the paper which allows diffusion of the ink to take place and leads to low print sharpness. One method of achieving a short drying time while providing high print density and sharpness is to use special silica-coated papers. Such papers however are expensive to produce.
[0003] U.S. Pat. No. 6,207,258 provides a partial solution to this problem by disclosing that pigmented ink jet print quality can be improved by treating the substrate surface with an aqueous sizing medium containing a divalent metal salt. Calcium chloride and magnesium chloride are preferred divalent metal salts. The sizing medium may also contain other conventional paper additives used in treating uncoated paper. Included in conventional paper additives are optical brightening agents (OBAs) which arc well known to improve considerably the whiteness of paper and thereby the contrast between the ink jet print and the background. U.S. Pat. No. 6,207,258 offers no examples of the use of optical brightening agents with the invention.
[0004] WO 2007/044228 claims compositions including an alkenyl succinic anhydride sizing agent and/or an alkyl ketene dimmer sizing agent, and incorporating a metallic salt. No reference is made to the use of optical brightening agents with the invention.
[0005] WO 2008/048265 claims a recording sheet for printing comprising a substrate formed from ligno cellulosic fibres of which at least one surface is treated with a water soluble divalent metal salt. The recording sheet exhibits an enhanced image drying time. Optical brighteners are included in a list of optional components of a preferred surface treatment comprising calcium chloride and one or more starches. No examples are provided of the use of optical brighteners with the invention.
[0006] WO 2007/053681 describes a sizing composition that, when applied to an ink jet substrate, improves print density, colour-to-colour bleed, print sharpness and/or image dry time. The sizing composition comprises at least one pigment, preferably either precipitated or ground calcium carbonate, at least one binder, one example of which is a multicomponent system including starch and polyvinyl alcohol, at least one nitrogen containing organic species, preferably a polymer or copolymer of diallyldimethyl ammonium chloride (DADMAC), and at least one inorganic salt. The sizing composition may also contain at least one optical brightening agent, examples of which are Leucophor BCW and Leucophor FTS from Clariant.
[0007] The advantages of using a divalent metal salt, such as calcium chloride, in substrates intended for pigmented ink jet printing can only be fully realized when a compatible water-soluble optical brightener becomes available. It is well-known however that water-soluble optical brighteners are prone to precipitation in high calcium concentrations. (See, for example, page 50 in Tracing Technique in Geohydrology by Werner Kass and Horst Behrens, published by Taylor & Francis, 1998.)
[0008] Accordingly, there is a need for a water-soluble optical brightener which has good compatibility with sizing compositions containing a divalent metal salt.
DESCRIPTION OF THE INVENTION
[0009] It has now been found that optical brighteners of formula (I) have surprisingly good compatibility with sizing compositions containing a divalent metal salt.
[0010] The present invention therefore provides a sizing composition for optical brightening of substrates, preferably paper, which is especially suitable for pigmented ink jet printing, comprising
(a) at least one binder; (b) at least one divalent metal salt, the at least one divalent metal salt being selected from the group consisting of calcium chloride, magnesium chloride, calcium bromide, magnesium bromide, calcium iodide, magnesium iodide, calcium nitrate, magnesium nitrate, calcium formate, magnesium formate, calcium acetate, magnesium acetate, calcium sulphate, magnesium sulphate, calcium thiosulphate or magnesium thiosulphate or mixtures of said compounds; (c) water, and (d) at least one optical brightener of formula (1)
[0000]
[0000] in which
M and X are identical or different and independently from each other selected from the group consisting of hydrogen, an alkali metal cation, ammonium, ammonium which is mono-, di- or trisubstituted by a C1-C4 linear or branched alkyl radical, ammonium which is mono-, di- or trisubstituted by a C1-C4 linear or branched hydroxyalkyl radical, or mixtures of said compounds and n is in the range from 0 to 6.
[0017] Preferred compounds of formula (1) are those in which
M and X are identical or different and independently from each other selected from the group consisting of an alkali metal cation and trisubstituted C1-C4 linear or branched hydroxyalkyl radical, or mixtures of said compounds and n is in the range from 0 to 6.
[0020] More preferred compounds of formula (1) are those in which
M and X are identical or different and independently from each other selected from the group consisting of Li, Na, K and trisubstituted C1-C3 linear or branched hydroxyalkyl radical, or mixtures of said compounds and n is in the range from 0 to 6.
[0022] Especially preferred compounds of formula (1) are those in which
M and X are identical or different and independently from each other selected from the group consisting of Na, K and triethanolamine, or mixtures of said compounds and n is in the range from 0 to 6.
[0025] The concentration of optical brightener in the sizing composition may be between 0.2 and 30 g/l, preferably between 1 and 15 g/l, most preferably between 2 and 12 g/l.
[0026] The binder is typically an enzymatically or chemically modified starch, e.g. oxidized starch, hydroxyethylated starch or acetylated starch. The starch may also be native starch, anionic starch, a cationic starch, or an amphipathic depending on the particular embodiment being practiced. While the starch source may be any, examples of starch sources include corn, wheat, potato, rice, tapioca, and sago. One or more secondary binders e.g. polyvinyl alcohol may also be used.
[0027] The concentration of binder in the sizing composition may be between 1 and 30% by weight, preferably between 2 and 20% by weight, most preferably between 5 and 15% by weight.
[0028] Preferred divalent metal salts are selected from the group consisting of calcium chloride, magnesium chloride, calcium bromide, magnesium bromide, calcium sulphate, magnesium sulphate, calcium thiosulphate or magnesium thiosulphate or mixtures of said compounds.
[0029] Even more preferred divalent metal salts are selected from the group consisting of calcium chloride or magnesium chloride or mixtures of said compounds.
[0030] The concentration of divalent metal salt in the sizing composition may be between 1 and 100 g/l, preferably between 2 and 75 g/l, most preferably between 5 and 50 g/l.
[0031] When the divalent metal salt is a mixture of a calcium salt and a magnesium salt, the amount of calcium salt may be in the range of 0.1 to 99.9%.
[0032] The pH value of the sizing composition is typically in the range of 5-13, preferably 6-11.
[0033] In addition to one or more binders, one or more divalent metal salts, one or more optical brighteners and water, the sizing composition may contain by-products formed during the preparation of the optical brightener as well as other conventional paper additives. Examples of such additives are carriers, defoamers, wax emulsions, dyes, inorganic salts, solubilizing aids, preservatives, complexing agents, surface sizing agents, cross-linkers, pigments, special resins etc.
[0034] In an additional aspect of the invention, the optical brightener may be pre-mixed with polyvinyl alcohol in order to boost the performance of the optical brightener in sizing compositions. The polyvinyl alcohol may have any hydrolysis level including from 60 to 99%. The optical brightener/polyvinyl alcohol mixture may contain any amount of optical brightener and polyvinyl alcohol. Examples of making optical brightener/polyvinyl alcohol mixtures can be found in WO 2008/017623.
[0035] The optical brightener/polyvinyl alcohol mixture may be an aqueous mixture.
[0036] The optical brightener/polyvinyl alcohol mixture may contain any amount of optical brightener including from 10 to 50% by weight of at least one optical brightener. Further, the optical brightener/polyvinyl alcohol mixture may contain any amount of polyvinyl alcohol including from 0.1 to 10% by weight of polyvinyl alcohol.
[0037] The sizing composition may be applied to the surface of a paper substrate by any surface treatment method known in the art. Examples of application methods include size-press applications, calendar size application, tub sizing, coating applications and spraying applications. (See, for example, pages 283-286 in Handbook for Pulp & Paper Technologists by G. A. Smook, 2 nd Edition Angus Wilde Publications, 1992 and US 2007/0277950.) The preferred method of application is at the size-press such as puddle size press or rod-metered size press . A preformed sheet of paper is passed through a two-roll nip which is flooded with the sizing composition. The paper absorbs some of the composition, the remainder being removed in the nip.
[0038] The paper substrate contains a web of cellulose fibres which may he synthetic or sourced from any fibrous plant including woody and nonwoody sources. Preferably the cellulose fibres are sourced from hardwood and/or softwood. The fibres may be either virgin fibres or recycled fibres, or any combination of virgin and recycled fibres.
[0039] The cellulose fibres contained in the paper substrate may be modified by physical and/or chemical methods as described, for example, in Chapters 13 and 15 respectively in Handbook for Pulp & Paper Technologists by G. A. Smook, 2 nd Edition Angus Wilde Publications, 1992. One example of a chemical modification of the cellulose fibre is the addition of an optical brightener as described, for example, in EP 884,312, EP 899,373, WO 02/055646, WO 2006/061399, WO 2007/017336, WO 2007/143182, US 2006-0185808, and US 2007-0193707 .
[0040] The sizing composition is prepared by adding the optical brightener (or optical brightener/polyvinyl alcohol mixture) and the divalent metal salt to a preformed aqueous solution of the binder at a temperature of between 20° C. and 90° C. Preferably the divalent metal salt is added before the optical brightener (or optical brightener/polyvinyl alcohol mixture), and at a temperature of between 50° C. and 70° C.
[0041] The paper substrate containing the sizing composition and of the present invention may have any ISO brightness, including ISO brightness that is at least 80, at least 90 and at least 95.
[0042] The paper substrate of the present invention may have any CIE Whiteness, including at least 130, at least 146, at least 150, and at least 156. The sizing composition has a tendency to enhance the CIE Whiteness of a sheet as compared to conventional sizing compositions containing similar levels of optical brighteners.
[0043] The sizing composition of the present invention has a decreased tendency to green a sheet to which it has been applied as compared to that of conventional sizing compositions containing comparable amounts of optical brighteners. Greening is a phenomenon related to saturation of the sheet such that a sheet does not increase in whiteness even as the amount of optical brightener is increased. The tendency to green is measured is indicated by from the a*-b* diagram, a* and b* being the colour coordinates in the CIE Lab system. Accordingly, the sizing composition of the present invention affords the user the ability to efficiently increase optical brightener concentrations on the paper in the presence of a divalent metal ion without reaching saturation, while at the same time maintaining or enhancing the CIE Whiteness and ISO Brightness of the paper.
[0044] While the paper substrates of the present invention show enhanced properties suitable for inkjet printing, the substrates may also be used for multi-purpose and laserjet printing as well. These applications may include those requiring cut-size paper substrates, as well as paper roll substrates.
[0045] The paper substrate of the present invention may contain an image. The image may be formed on the substrate with any substance including dye, pigment and toner.
[0046] Once the image is formed on the substrate, the print density may be any optical print density including an optical print density that is at least 1.0, at least 1.2, at least 1.4, at least 1.6. Methods of measuring optical print density can be found in EP 1775141.
[0047] The preparation of a compound of formula (1) in which M=Na and n=6 has been described previously in WO 02/060883 and WO 02/077106. No examples have been provided of the preparation of a compound of formula (I) in which M≠X and n<6.
[0048] The compounds of formula (1) are prepared by stepwise reaction of a cyanuric halide with
[0049] a) an amine of formula
[0000]
[0000] in the free acid, partial- or full salt form,
[0050] (b) a diamine of formula
[0000]
in the free acid, partial- or full salt form,
[0052] and
[0053] c) diisopropanolamine of formula
[0000]
[0054] As a cyanuric halide there may be employed the fluoride, chloride or bromide. Cyanuric chloride is preferred.
[0055] Each reaction may be carried out in an aqueous medium, the cyanuric halide being suspended in water, or in an aqueous/organic medium, the cyanuric halide being dissolved in a solvent such as acetone. Each amine may be introduced without dilution, or in the form of an aqueous solution or suspension. The amines can be reacted in any order, although it is preferred to react the aromatic amines first. Each amine may be reacted stoichiometrically, or in excess. Typically, the aromatic amines are reacted stoichimetrically, or in slight excess; diisopropanolamine is generally employed in an excess of 5-30% over stoichiometry.
[0056] For substitution of the first halogen of the cyanuric halide, it is preferred to operate at a temperature in the range of 0 to 20° C., and under acidic to neutral pH conditions, preferably in the pH range of 2 to 7. For substitution of the second halogen of the cyanuric halide, it is preferred to operate at a temperature in the range of 20 to 60° C., and under weakly acidic to weakly alkaline conditions, preferably at a pH in the range of 4 to 8. For substitution of the third halogen of the cyanuric halide, it is preferred to operate at a temperature in the range of 60 to 102° C., and under weakly acidic to alkaline conditions, preferably at a pH in the range of 7 to 10.
[0057] The pH of each reaction is generally controlled by addition of a suitable base, the choice of base being dictated by the desired product composition. Preferred bases are, for example, alkali metal (e.g., lithium, sodium or potassium) hydroxides, carbonates or bicarbonates, or aliphatic tertiary amines e.g. triethanolamine or triisopropanolamine. Where a combination of two or more different bases is used, the bases may be added in any order, or at the same time.
[0058] Where it is necessary to adjust the reaction pH using acid, examples of acids that may be used include hydrochloric acid, sulphuric acid, formic acid and acetic acid.
[0059] Aqueous solutions containing one or more compounds of general formula (1) may optionally be desalinated either by membrane filtration or by a sequence of precipitation followed by solution using an appropriate base.
[0060] The preferred membrane filtration process is that of ultrafiltration using, e.g., polysulphone, polyvinylidenefluoride, cellulose acetate or thin-film membranes.
EXAMPLES
[0061] The following examples shall demonstrate the instant invention in more details. If not indicated otherwise, “parts” means “parts by weight” and “%” means “% by weight”.
Example 1
[0062] Stage 1: 31.4 parts of aniline-2,5-disulphonic acid monosodium salt are added to 150 parts of water and dissolved with the aid of an approx. 30% sodium hydroxide solution at approx. 25° C. and a pH value of approx. 8-9. The obtained solution is added over a period of approx. 30 minutes to 18.8 parts of cyanuric chloride dispersed in 30 parts of water, 70 parts of ice and 0.1 part of an antifoaming agent. The temperature is kept below 5° C. using an ice/water bath and if necessary by adding ice into the reaction mixture. The pH is maintained at approx. 4-5 using an approx. 20% sodium carbonate solution. At the end of the addition, the pH is increased to approx. 6 using an approx. 20% sodium carbonate solution and stirring is continued at approx. 0-5° C. until completion of the reaction (3-4 hours).
[0063] Stage 2: 8.8 parts of sodium bicarbonate are added to the reaction mixture. An aqueous solution, obtained by dissolving under nitrogen 18.5 parts of 4,4′-diaminostilbene-2,2′-disulphonic acid in 80 parts of water with the aid of an approx. 30% sodium hydroxide solution at approx. 45-50° C. and a pH value of approx. 8-9, is dropped into the reaction mixture. The resulting mixture is heated at approx. 45-50° C. until completion of the reaction (3-4 hours).
[0064] Stage 3: 17.7 parts of Diisopropanolamine are then added and the temperature is gradually raised to approx. 85-90° C. and maintained at this temperature until completion of the reaction (2-3 hours) while keeping the pH at approx. 8-9 using an approx. 30% sodium hydroxide solution. The temperature is then decreased to 50° C. and the reaction mixture is filtered and cooled down to room temperature. The solution is adjusted to strength to give an aqueous solution of a compound of formula (1) in which M=X═Na and n=6 (0.125 mol/kg, 17.8%).
Example 2
[0065] An aqueous solution of a compound of formula (1) in which M=Na, X═K and 4.5≦n≦5.5 (0.125mol/kg, approx. 18.0%) is obtained following the same procedure as in Example 1 with the sole difference that an approx. 30% potassium hydroxide solution is used instead of an approx. 30% sodium hydroxide solution in Stage 3.
Example 3
[0066] An aqueous solution of a compound of formula (1) in which M=Na, X═K and 2.5≦n≦4.5 (0.125 mol/kg, approx. 18.3%) is obtained following the same procedure as in Example 1 with the sole differences that 10 parts of potassium bicarbonate are used instead of 8.8 parts of sodium bicarbonate in Stage 2 and an approx. 30% potassium hydroxide solution is used instead of an approx. 30% sodium hydroxide solution in Stages 2 and 3.
Example 4
[0067] An aqueous solution of a compound of formula (1) in which M=Na, X═K and 0≦n≦2.5 (0.125 mol/kg, approx. 18.8%) is obtained following the same procedure as in Example 1 with the sole differences that an approx. 30% potassium hydroxide solution is used in place of an approx. 30% sodium hydroxide solution in Stages 1, 2 and 3, an approx. 20% potassium carbonate solution is used instead of an approx. 20% sodium carbonate solution in Stage 1, and 10 parts of potassium bicarbonate are used instead of 8.8 parts of sodium bicarbonate in Stage 2.
Example 5
[0068] An aqueous solution of a compound of formula (1) in which M=Na, X═Li and 4.5≦n≦5.9 (0.125 mol/kg, approx. 17.7%) is obtained following the same procedure as in Example 1 with the sole difference that an approx. 10% lithium hydroxide solution is used instead of an approx. 30% sodium hydroxide solution in Stage 3.
Example 6
[0069] An aqueous solution of a compound of formula (1) in which M=Na, X═Li and 2.5≦n≦4.5 (0.125 mol/kg, approx. 17.3%) is obtained following the same procedure as in Example 1 with the sole differences that 3.7 parts of lithium carbonate are used instead of 8.8 parts of sodium bicarbonate in Stage 2 and an approx. 10% lithium hydroxide solution is used instead of an approx. 30% sodium hydroxide solution in Stages 2 and 3.
Example 7
[0070] A compound of formula (1) in which M=H is isolated by precipitation with concentrated hydrochloric acid of the concentrated solution of the compound of formula (1) obtained in Example 1, followed by filtration. The presscake is then dissolved in an aqueous solution of 7 equivalents of triethanolamine to give an aqueous solution of a compound of formula (1) in which M=Na, X=triethanolammonium and 1≦n≦3 (0.125 mol/kg, approx. 24.2%).
Example 8
[0071] Optical brightening solution 8 is produced by stirring together
an aqueous solution containing compound of formula (1) in which M=Na, X═K and 0≦n≦2.5 prepared according to example 4, a polyvinyl alcohol having a degree of hydrolysis of 85% and a Brookfield viscosity of 3.4-4.0 mPa.s and water
while heating to 90-95° C., until a clear solution is obtained that remains stable after cooling to room temperature.
[0075] The parts of each component are selected in order to get a final aqueous solution 8 comprising a compound of formula (1) in which M=Na, X═K and 0≦n≦2.5 prepared according to example 4 at a concentration of 0.125 mol/kg and 2.5% of a polyvinyl alcohol having a degree of hydrolysis of 85% and a Brookfield viscosity of 3.4-4.0 mPa.s. The pH of solution 8 is in the range 8-9.
Application Examples 1 to 8
[0076] Sizing compositions are prepared by adding an aqueous solution of a compound of formula (1) prepared according to Examples 1 to 8 at a range of concentrations from 0 to 50 g/l (from 0 to approx. 12.5 g/l of optical brightener) to a stirred, aqueous solution of calcium chloride (35 g/l) and an anionic starch (50 g/l) (Penford Starch 260) at 60° C. The sizing solution is allowed to cool, then poured between the moving rollers of a laboratory size-press and applied to a commercial 75 g/m 2 AKD (alkyl ketene dimer) sized, bleached paper base sheet. The treated paper is dried for 5 minutes at 70° C. in a flat bed drier.
[0077] The dried paper is allowed to condition, and then measured for CIE whiteness on a calibrated Auto Elrepho spectrophotometer. The results are shown in Table 1.
Comparative Example 1
[0078] Sizing compositions are prepared by adding an aqueous solution of the Hexasulfo-compound disclosed in the table on page 8 of the US 2005/0124755 A 1 at a range of concentrations from 0 to 50 g/l (from 0 to approx. 12.5 g/l of optical brightener) to a stirred, aqueous solution of calcium chloride (35 g/l) and an anionic starch (50 g/l) (Penford Starch 260) at 60° C. The sizing solution is allowed to cool, then poured between the moving rollers of a laboratory size-press and applied to a commercial 75 g/m 2 AKD (alkyl ketene dimer) sized, bleached paper base sheet. The treated paper is dried for 5 minutes at 70 ° C. in a flat bed drier.
[0079] The dried paper is allowed to condition, and then measured for CIE whiteness on a calibrated Auto Elrepho spectrophotometer. The results are shown in Table 1.
[0000]
TABLE 1
CIE Whiteness
Com-
Conc.
Application example
parative
g/l
1
2
3
4
5
6
7
8
1
0
103.7
103.7
103.7
103.7
103.7
103.7
103.7
103.7
103.7
20
130.3
131.4
131.7
131.9
131.4
131.7
132.0
132.2
129.0
30
134.7
135.0
135.4
135.8
134.7
135.1
135.9
136.5
132.5
40
137.3
137.8
138.0
138.3
137.1
137.2
138.5
139.8
134.6
50
140.3
140.7
141.2
141.7
139.8
140.4
142.0
143.0
138.0
[0080] The results in Table 1 clearly demonstrate the excellent whitening effect afforded by the compositions of the invention.
[0081] Printability evaluation was done with a black pigment ink applied to the paper using a draw down rod and allowed to dry.
[0082] Optical density was measured using an Ihara Optical Densitometer R710, The results are shown in Table 2.
[0000]
TABLE 2
Optical Density
Paper sheet treated
2
1.02
according to application
4
1.12
example
7
1.06
Paper sheet treated
1
1.02
according to comparative
example
[0000] Optical Density=log 10 1/ R Where R =Reflectance
[0083] The results in Table 2 show that the composition of the invention has no adverse effect on ink print density. | The instant invention relates to liquid compositions comprising derivatives of diaminostilbene, binders and ink fixing agents such as divalent metal salts for the optical brightening of substrates suitable for high quality ink jet printing. | 3 |
PRIORITY CLAIM
The present application is a continuation of U.S. application Ser. No. 10/347,085 filed Jan. 17, 2003, and issued as U.S. Pat No. 7,410,615 which claims priority from U.S. Provisional Application No. 60/351,700 filed Jan. 24, 2002, and entitled “PRECISION LIQUID DISPENSING SYSTEM.”
BACKGROUND OF THE INVENTION
The invention relates generally to systems for depositing small amounts of liquid having volumes in the range of about 0.5 μL to 2 mL. Although there are various end uses for such systems, they are particularly useful in connection with microscale chemical and biological analyses. Frequently, the microdispensing system will be used to dispense reagent into a microplate having an array of small wells which hold liquid. A common size is a 96 well plate, measuring about 80 by 120 mm and having round sample wells having a diameter of about 6.5 mm. More recently, plates having 384 and 1536 wells have become available, and the wells in such plates are correspondingly smaller. Thus, reagents must be dispensed in extremely small quantities, and achieving dispensing accuracy and repeatability becomes increasingly difficult.
Depositing small droplets of liquid for various purposes, including ink jet printing has been of interest in recent years. For example, in U.S. Pat. No. 5,743,960 a system using a solenoid valve is employed. The system features the use of a positive displacement pump to provide the needed flow while the solenoid valve is opened and closed to form the desired droplet size, said to be in the range of 1-4 nanoliters (1-4 mL). Substitution of a piezoelectric dispenser for the solenoid valve dispenser was suggested. The volume of liquid deposited was intended to be in the range of 0.42×10 −9 to 2×10 −6 liters (0.42 mL to 2 μL).
Another patent disclosing the use of a positive displacement pump to supply a piezoelectric dispensing nozzle is U.S. Pat. No. 6,203,759. In an alternative system, a reservoir containing a liquid is maintained at a desired pressure. In both types of dispensing systems a sample typically is aspirated into the piezoelectric nozzle and then dispensed, using a liquid different from that being dispensed.
SUMMARY OF THE INVENTION
In accordance with the present invention, a system is provided for dispensing microdrops of reagent in small, precisely metered quantities from a reagent reservoir containing a fluid reagent to be dispensed. The reagent in the reservoir is maintained under a controlled pressure, and is supplied to multiple nozzles for dispensing microdrops of the reagent. Multiple solenoid-actuated valves are connected between the reservoir and the nozzles for controlling the flow of the reagent from the reservoir to the nozzles, with each valve being connected to one of the nozzles. Electrical pulses are supplied separately to each of the solenoid valves to separately control the opening and closing of each valve to dispense predetermined quantities of the reagent through each nozzle at predetermined times.
In a preferred embodiment of the invention, the reagent in the reservoir is maintained under a controlled pressure by an air pump that supplies pressurized air to the reservoir. An electrical control signal is supplied to the pump to control the pressure of the air supplied by the pump to the reservoir. A transducer senses the pressure within the reservoir and produces a signal representing that pressure. A closed-loop control system uses the transducer signal in a PID algorithm to maintain the desired pressure in the reservoir by regulating the electrical control signal supplied to the pump.
A preferred arrangement for controlling the solenoid valves permits selection of the desired volume of reagent to be dispensed from each nozzle, and a calibration table that specifies the widths of the electrical pulses required to dispense specified volumes of the reagent. When a desired volume not specified in the table is selected, a required pulse width is calculated from the pulse widths specified in the table for the two specified volumes closest to the selected desired volume. The calculation is preferably performed using linear interpolation between the two closest values in the table.
The invention provides improved accuracy and repeatability of dispensing, with the option of dispensing smaller volumes not currently available in commercial products utilizing solenoid valves. The invention allows dispensing in low volumes, e.g., from 0.5 μL to 2 mL, with full chemical compatibility with common chemical reagents used in biotechnology and chemical laboratories.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a block diagram of an eight-nozzle precision reagent-dispensing system embodying the invention; and
FIG. 2 is a block diagram of a 32-nozzle precision reagent-dispensing system embodying the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Although the invention will be described in connection with certain preferred embodiments, it will be understood that the invention is not limited to those particular embodiments. On the contrary, the invention is intended to include all alternatives, modifications and equivalent arrangements as may be included within the spirit and scope of the invention as defined by the appended claims.
Turning now to the drawings, and referring first to FIG. 1 , the reagent to be dispensed is contained in a reservoir 10 (preferably a glass container) having a pressurized headspace at the top of the reservoir. An output line 11 leads from a supply line 12 near the bottom of the reservoir 10 to a manifold 13 having eight output lines 14 a - 14 h leading to eight high-speed, solenoid-actuated valves 15 a - 15 h . Each valve 15 carries a dispensing nozzle 16 . Whenever one or more of the valves 15 is open, the pressure in the reservoir 10 forces reagent from the reservoir through the line 11 and the manifold 13 . Manifold 13 is designed to allow equal flow distribution from the single output line 11 to the eight output line 14 a - h and to the open valve(s) 15 is to the corresponding dispensing nozzle(s) 16 . In a preferred embodiment, the manifold 13 is equipped with a bottom seal fitting 13 a , has a fully swept internal liquid path to reduce the possibility of trapping air and is made of a polyaryletherketone (“PEEK”) resin which provides good mechanical properties in combination with good resistance to the types of reagents commonly used in this type of equipment. The line 11 leading to the manifold 13 is preferably 0.125″ ID, 0.1875″ OD PFA Teflon® tubing, and the lines 14 a - 14 h connecting the manifold 13 to the valves 15 a - 15 h are preferably 0.040″ ID, 0.0625″ OD Tefzel® tubing. Lines 14 a - 14 h and line 11 are coupled to the internals of manifold 13 in a manner that avoids unequal flow distribution, additional restrictions in metering, or trapping of air, all of which cause degradation of target dispense accuracy and precision.
The pressure within the reservoir 10 is controlled by an air pump 20 that supplies pressurized air to the reservoir via line 21 at a controlled pressure, e.g., about 5 psig (34.5 kPa gauge). The pump 20 preferably includes a brushless DC motor (with a three-wire control option) that is controlled by a system controller 22 via electrical line 23 . The system controller 22 includes a microprocessor that receives a feedback signal from a transducer 24 sensing the pressure within the reservoir 10 . The transducer 24 is connected to a pressure tap line 25 that comes off of the reservoir 10 , and generates an electrical signal on line 26 corresponding to the pressure sensed by the transducer in the tap line 25 . The pressure supply line 21 , the pressure sensor tap line 25 , and the reagent supply line 11 enter/exit the reagent reservoir 10 through a cap 10 a . The lines 21 and 25 are attached to the cap 10 a via barb fittings, while the liquid supply line 11 passes through the cap and is captured by a flangeless fitting 11 a . The lines 21 and 25 are preferably 0.125″ ID, 0.25″ OD Tygon® tubing.
The microprocessor in the system controller 22 uses the signal from the transducer 24 in a standard PID (proportional, integral, derivative) control algorithm, to produce an output signal on line 23 to control the pressure within the reagent reservoir, preferably to within 0.02 psi. That is, the microprocessor continually compares the actual reservoir pressure, represented by the transducer signal on line 26 , with the desired or “set point” pressure, e.g., 5 psig (34.5 kPa gauge), using the PID algorithm to produce the requisite output signal for maintaining the desired pressure in the reservoir 10 . The pressure is maintained within a variation of about ±0.5%. A preferred minimum flow rate for the pump 20 is 500 ml/min. at a pressure of 5 psig.
The system controller 22 also produces the electrical pulses that control the times at which each of the valves 15 a - 15 h is opened and closed. These pulses are generated on any of eight different output lines 30 a - 30 h , each of which is connected to one of the solenoid-actuated valves 15 a - 15 h . Each pulse rises from a differential voltage of zero to 24 DC volts spike pulse for 2 milliseconds, then reduces to a differential of 5 volts to hold open the valve 15 receiving that pulse, remains at the 5-volt level for a time period sufficient to dispense the selected volume of reagent through the opened valve, and then drops to a differential voltage of zero volts at the end of that time period to close the valve.
The desired volume of reagent to be dispensed from each nozzle 16 is selected by the user via a keypad or other manual input device on the front of a control panel (not shown). This manual input provides the microprocessor with a signal representing the selected volume. A memory associated with the microprocessor stores a calibration table that specifies the widths of the electrical pulses required to dispense specified volumes of the reagent. When a volume not specified in the table is selected, the microprocessor calculates a required pulse width from the pulse widths specified in the table for the two specified volumes closest to the selected volume. This calculation is preferably performed using linear interpolation between the two closest values in the table.
The calibration table is generated initially by supplying one of the solenoid-actuated valves with a succession of pulses of progressively increasing width, and measuring the actual volume of reagent dispensed through the nozzle connected to that valve. These measured volumes are stored in the table, along with the pulse width that produced each volume. Then when the user selects a desired volume, the microprocessor finds either that volume, or the two closest volumes in the table. If the exact value of the selected volume is in the table, the microprocessor generates a pulse having the width specified for that volume in the table. If the exact value is not in the table, then the microprocessor uses the two closest volume values, and their corresponding pulse widths, to calculate the pulse width required to dispense the volume selected by the user. Linear interpolation may be used for the calculation.
The solenoid-actuated valves used in the dispensing system may be selected on the basis of the specified minimum volume to be dispensed by the system. For example, if the specified minimum volume to be dispensed is 0.5 μL, a valve capable of dispensing a volume of approximately 0.125 μL is preferably selected, to allow for a four to one safety factor.
FIG. 2 illustrates four dispensing systems of the type illustrated in FIG. 1 arranged in parallel to provide simultaneous dispensing of reagent from 32 nozzles 40 a - 40 h , 41 a - 41 h , 42 a - 42 h and 43 a - 43 h . This arrangement allows rapid filling of multiple wells in microplates having large numbers of wells.
In a test of the invention, a sample plate having 96 wells was used, each row of eight wells received sample liquid simultaneously. After each row received samples, the next row of wells received samples of the liquid and so on until all 96 wells had been sampled. Each of the eight valves (Lee Valve Company) opened for 5.0 milliseconds and dispensed 0.5 μL of the sample liquid into a well which had been primed with 199.5 μL of deionized water. After each plate had received 96 samples, the liquid delivery system was flushed and re-primed to simulate commercial practice and thus, to introduce potential variation in the amounts of liquid delivered to each well associated with changing or replenishing the dispensed liquid.
The liquid dispensed was a 5 g/L solution of a tartrazine yellow dye in deionized water, contained in a 1000 mL bottle, which was pressured to 5 psig ±0.02 (34.5 kPa). The arrangement of the tubing supplying liquid to each valve was made as uniform as possible. Measurement of the amount of liquid dispensed was done indirectly by reading the optical density of the liquid with a Spectracount® photometer (Packard Instrument Company). Values for the ten sample plates are shown in the following table.
Plate No.
Mean Optical Density Reading
Coeff. Of Variation, %
1
0.3738
1.23
2
0.3729
1.42
3
0.3725
1.32
4
0.3674
1.62
5
0.3723
1.44
6
0.3711
1.32
7
0.3676
1.61
8
0.3644
1.69
9
0.3698
1.50
10
0.3680
1.48
The mean value of the optical density measurements was 0.370 over all the 10 sample plates, with a standard deviation of 0.003 or coefficient of variation of 0.823%. Within individual sample plates, the minimum coefficient of variation was 1.231% on plate 1 , while the maximum coefficient of variation was 1.686% on plate 8 . The total variation from the mean optical density reading was about 1.25% across all the 10 sample plates. It should be evident that the system of the invention is capable of depositing the very precise and repeatable samples of liquids required for the tests typically carried out in such sample plates.
In one application of the dispensing system, the nozzles are mounted on a moveable support and moved in the Y plane into a location where the nozzle tips are aligned with the well of a microplate into which microdrops of the reagent are dispensed. The microplate is moved by a separate plate holder and displaced horizontally in the X plane. Thus, the nozzles are moved within the Y axis while the microplate that receives the microdrops moves in the X-axis directly and precisely under the nozzles. Alternatively, the nozzles may be stationary and the microplate moved under the nozzles. It is of course possible to move both the nozzles and the microplate for maximum flexibility and speed of operation.
In practice, it is not desirable to carry out such movements manually, using visual observation by the operator. To assure accuracy in repetitive steps of dispensing reagent into multiple wells, computer control of the movements of the nozzles and/or the microplate generally will be provided. The operator of the apparatus will instruct the instrument via a graphical user interface or by a separately linked computer to carry out a series of movements intended to transfer reagent from the reservoir to the microplate. It will be appreciated that such a sequence of movements may take place in three dimensions, usually called X and Y defining the position in a horizontal plane and Z defining the position in the vertical direction.
While the present invention has been described with reference to one or more embodiments, those skilled in the art will recognize that many changes may be made there to without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof are contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims. | A system for dispensing microdrops of reagent in small, precisely metered quantities maintains the fluid reagent to be dispensed in a reservoir under a controlled pressure. The reagent is dispensed through multiple nozzles connected to solenoid-actuated valves that control the flow of the reagent from the reservoir to the nozzles. Each valve is connected to one of the nozzles and electrical pulses are supplied separately to each of the valves to separately control the opening and closing of each valve to dispense predetermined quantities of the reagent through each nozzle at predetermined times. | 8 |
FIELD OF THE INVENTION
The present invention is directed to modification processes and modified articles. More specifically, the present invention is directed to modification processes for an increased stress area in a turbine component and modified turbine components.
BACKGROUND OF THE INVENTION
Turbine components such as airfoils experience extreme stresses during operation. Some of those stresses include increased pressure and temperature which may be concentrated on specific areas of the turbine component. One specific area is under the suction side leading edge tip shroud fillet of an airfoil, where increased stress may lead to a creep rupture or cracking
Stresses of this type can lead to early removal, discard and replacement of the expensive airfoil. This reduces the expected operational lifetime of the airfoil, increasing maintenance costs and operational costs of a system.
One modification method includes weld build ups over an increased stress area, followed by machining The weld build ups reduce material properties and increase the risk of stressing additional areas at the weld interface with the blade and in the weld metal. Additionally, current modification processes do not sufficiently increase material properties of the increased stress areas of the airfoil to provide a usable modified article.
A modification process to remove increased stress areas and increase material properties, as well as a modified article that do not suffer from one or more of the above drawbacks would be desirable in the art.
BRIEF DESCRIPTION OF THE INVENTION
In an exemplary embodiment, a modification process includes locating an area in an article, removing the area by machining to form a machined region, inserting a modification material into the machined region, securing the modification material to the article, machining the modification material flush with a geometry of the article, and applying a coating over at least a portion of the article.
In another exemplary embodiment, a modification process includes locating an area under a suction side leading edge tip shroud fillet of an airfoil, removing the area by machining to form a hole in the airfoil, inserting a modification material into the hole, the modification material having improved material properties as compared to an original base material, securing the modification material in place, machining the modification material and the airfoil to form a new contour of the fillet, and applying a coating over at least a portion of the airfoil.
In another exemplary embodiment, a modified article includes a turbine component, and a modification material secured within the turbine component at a location previous occupied by an original base material subject to increased stress. The modification material has improved material properties as compared to the original base material, the improved material properties increasing stress tolerance of the turbine component.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow chart of a modification process according to an embodiment of the disclosure.
FIG. 2 is a perspective side view of an increased stress area of a turbine blade according to an embodiment of the disclosure.
FIG. 3 is a perspective side view of a machined region of a turbine blade according to an embodiment of the disclosure.
FIG. 4 is a perspective view of a modification material in a machined region of a turbine blade according to an embodiment of the disclosure.
FIG. 5 is a perspective view of a modified turbine blade according to an embodiment of the disclosure.
Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.
DETAILED DESCRIPTION OF THE INVENTION
Provided are an exemplary modification process and modified article. Embodiments of the present disclosure, in comparison to processes and articles not using one or more of the features disclosed herein, increase operational life of a turbine component, increase efficiency of turbine component repair, reduce scrappage of turbine components, decrease stress during modification, improve material properties of a modified article, increase stress resistance of turbine components, reduce or eliminate creep rupture stress, or a combination thereof
Referring to FIG. 1 - FIG. 5 , in one embodiment, a modification process 100 removes an area 105 of an article 101 , and replaces the area 105 with a modification material 124 to increase an operational life of the article 101 . The article 101 is any suitable article such as, but not limited to, a turbine component. The modification process 100 includes removing a coating 108 (step 110 ) from the article 101 , locating (step 120 ) the area 105 in the article 101 , removing the area 105 (step 130 ) by machining while forming a machined region 115 , inserting (step 140 ) a modification material 124 into the machined region 115 , securing (step 150 ) the modification material 124 within the article 101 , machining (step 160 ) the modification material 124 to be flush with an existing geometry of the article 101 , inspecting (step 170 ) a modified portion, and re-applying (step 180 ) the coating 108 over the modified portion. In another embodiment, the modification process 100 includes drilling (step 190 ) internal cooling holes.
The article 101 may be any suitable article such as, but not limited to a turbine component, an airfoil, (such as a turbine airfoil identified as a General Electric Company 7 FA or a S 2 B), a bucket 102 , a shroud 103 , a nozzle, a hot gas path component, or a combination thereof The area 105 may be any portion of the article 101 that is subject to various increased stresses including, but not limited to, stress-rupture, increased temperature, alternating stresses, fatigue, and/or pressure. In one embodiment, the area 105 includes a section of distressed material such as, a pit, a crack, erosion, or a combination thereof. In another embodiment, the distressed material may be formed from any one of a number of sources, the modification process 100 being directed to the removal of the distressed material (step 130 ) after location (step 120 ) of the area 105 through any suitable means of inspection. Suitable means of inspection include, but are not limited to visual inspection, magnetic particle inspection (for ferrous alloys), eddy current, acoustic emission, pulsed laser, infrared, ultrasonic, radiographic, fluorescent penetrant inspection (FPI), or a combination thereof.
In one embodiment, the coating 108 is removed (step 110 ) from the base material 109 of the article 101 prior to locating (step 120 ) the area 105 . However, depending upon the inspection technique utilized, the area 105 may be located prior to removal of the coating 108 , so that the sequence of these steps may be interchangeable. The coating 108 is removed (step 110 ) by any suitable method capable of exposing the base material 109 . Suitable methods of removing (step 110 ) the coating 108 include, but are not limited to, water jet processes, chemical stripping, mechanical stripping, or a combination thereof. In one embodiment, the area 105 is located (step 120 ) without removing the coating 108 (step 110 ), after which removing the area 105 (step 130 ) by machining also removes the coating 108 , eliminating the need for a separate step.
Removing the area 105 (step 130 ) by machining forms the machined region 115 having any suitable geometry, the size of the machined region 115 being dependent on the size of the area 105 . A suitable geometry of the machined region 115 includes, but is not limited to, extending partially through the article 101 , extending fully through the article 101 , a hole, a cylinder, a cone, an oval, a portion of a sphere, a channel, a recess, or a combination thereof. In one embodiment, removing the area 105 (step 130 ) includes conventional machining or non-conventional machining, such as, but not limited to, thermal energy machining, chemical energy machining, laser machining, electrical energy machining (i.e. electrical discharge machining (EDM)), or a combination thereof. When removing the area 105 (step 130 ), the machining method preferably also removes any distressed material surrounding the area 105 . In one embodiment, a plurality of the areas 105 are removed (step 130 ) by machining, forming a plurality of the machined regions 115 .
Upon removing the area 105 (step 130 ) by machining, the modification material 124 is inserted (step 140 ) into the machined region 115 by any suitable method such as, but not limited to, laser deposition, layer by layer deposition, physical placement of the modification material 124 within the machined region 115 , or a combination thereof. The modification material 124 may have any suitable composition including, but not limited to, the same composition as a base material 109 of the article 101 , a composition substantially similar to the base material 109 , a composition having superior material properties as compared to the base material 109 , or a combination thereof. Superior material properties, as used herein, refers to an increased material strength, an increased ability to withstand stress, an increased ability to withstand strain, a decreased occurrence of distressed material formation, or a combination thereof. It is necessary to identify the material comprising the base material 109 in order to select the proper replacement material for the modification material 124 .
For example, in one embodiment, the modification material 124 is a single crystal grain structure composition, characterized by a nominal weight percentage of about 7.5% cobalt, about 7.5% chromium, about 6.5% tantalum, about 6.2% aluminum, about 5.0% tungsten, about 3.0% rhenium, about 1.5% molybdenum, about 0.15% hafnium, about 0.05% carbon, about 0.004% boron, between about 0.002% and about 0.03% yttrium, and a balance of nickel.
In another example, the modification material 124 is an equiaxed grain structure composition, characterized by a nominal weight percentage of between about 8.0% and about 8.7% Cr, between about 9% and about 10% Co, between about 5.25% and about 5.75% Al, up to about 0.9% Ti (for example, between about 0.6% and about 0.9%), between about 9.3% and about 9.7% W, up to about 0.6% Mo (for example, between about 0.4% and about 0.6%), between about 2.8% and about 3.3% Ta, between about 1.3% and about 1.7% Hf, up to about 0.1% C (for example, between about 0.07% and about 0.1%), up to about 0.02% Zr (for example, between about 0.005% and about 0.02%), up to about 0.02% B (for example, between about 0.01% and about 0.02%), up to about 0.2% Fe, up to about 0.12% Si, up to about 0.1% Mn, up to about 0.1% Cu, up to about 0.01% P, up to about 0.004% S, up to about 0.1% Nb, and a balance of nickel.
Following insertion (step 140 ) of the modification material 124 into the machined region 115 , the modification material 124 is secured (step 150 ) within the article 101 . The securing (step 150 ) of the modification material 124 includes, but is not limited to, brazing, welding, friction welding, laser welding, or a combination thereof. In one embodiment, brazing includes positioning any suitable filler material in the machined region 115 between the modification material 124 and the article 101 and heating the article 101 and the modification material 124 to a temperature above the melting temperature of the filler material, but below the melting point of the base material 109 . In another embodiment, the filler material has a composition, by weight, of about 14% Cr, about 9% Co, about 4% Al, about 2.5% B, and a balance of nickel. In one embodiment, the filler material has a composition, by weight, between about 13% and about 15% Cr, between about 9% and about 11% Co, between about 3.2% and about 3.8% Al, between about 2.2% and about 2.8% Ta, between about 2.5% and about 3.0% B, up to about 0.10 Y (with or without being present), incidental impurities, and a balance Ni. In another embodiment, the brazing is performed in a vacuum and includes heating at between about 2125° F. and about 2175° F. for between about 15 minutes and about 30 minutes, then diffusing at between about 1975° F. and about 2025° F. for between about 2 hours and about 4 hours. These materials are exemplary. It will be understood that the selection of the filler material will be dependent upon the base material 109 , which in turn will dictate brazing parameters for the substrate material/base material combination.
In one embodiment, the modification material 124 is a plug 125 having a geometry corresponding to the machined region 115 . For example, in another embodiment, the plug 125 has a conical geometry corresponding to conical geometry of the machined region 115 . The machined region 115 having the conical geometry provides superior mechanical retention of the plug 125 having the corresponding geometry. In one embodiment, the plug 125 is friction welded within the machined region 115 . The friction welding includes rotating the plug 125 with respect to the article 101 to generate a heat that secures the plug 125 (step 150 ) within the article 101 . During friction welding, the machined region 115 having a conical geometry reduces a heat input as compared to the cylindrical geometry.
After the securing (step 150 ) of the modification material 124 , the machining of the modification material 124 (step 160 ) forms a surface flush with an existing geometry of the article 101 or re-contours the modification material 124 and a portion of the article 101 . For the article 101 , this restores aerodynamics to the modified component. The article 101 is then inspected (step 170 ) and the coating 108 is then re-applied (step 180 ) over the base material 109 .
The coating 108 is re-applied (step 180 ) using any suitable coating method including, but not limited to, vapor deposition, slurry deposition, or any thermal spray process including high velocity oxygen fuel spraying (HVOF), high velocity air fuel spraying (HVAF), vacuum plasma spray (VPS), air plasma spray (APS), ion plasma deposition (IPD), electron-beam physical vapor deposition (EBPVD), cold spray, or a combination thereof. The coating 108 is any suitable material, such as but not limited to MCrAlX, NiAl, PtAl, PtNiAl, or a combination thereof. MCrAlX is an alloy having M selected from one or a combination of iron, nickel, cobalt, and combinations thereof; and Cr is chromium, Al is aluminum, and X is an element selected from the group of solid solution strengtheners and gamma prime formers consisting of Y, Tc, Ta, Re, Mo, and W and grain boundary strengtheners consisting of B, C, Hf, Zr, and combinations thereof.
In one embodiment, removing the areas 105 (step 130 ) by machining exposes the internal cooling holes extending within the article 101 . In another embodiment, the inserting (step 140 ) and the securing (step 150 ) of the modification material 124 within the machined region 115 may cover and/or close off the internal cooling holes. In a further embodiment, the internal cooling holes are restored by drilling (step 190 ) through the modification material 124 permitting cooling air to flow through the internal cooling holes that were covered and/or closed off by the securing of the plug 125 (step 150 ), and restoring a cooling airflow to the modified portion of the article 101 . The drilling (step 190 ) includes, but is not limited to, a shaped-tube electrochemical machining (STEM), an electron discharge machining (EDM), or a combination thereof. The drilling (step 190 ) is done either before or after the coating 108 is re-applied. In one embodiment, the article 101 does not include the internal cooling holes and the drilling (step 190 ) is not performed.
In one embodiment, the area 105 is an increased stress area of the article 101 . The increased stress area is exposed to stresses such as, but not limited to, increased temperatures, increased pressures, damaging airborne particles, or a combination thereof. For example, in one embodiment, the area 105 is located in a fillet 106 between the bucket 102 and the shroud 103 on a suction side 108 of the airfoil. The fillet 106 attaches the shroud 103 to the bucket 102 , and includes weld material or heat affected zone (HAZ) material which may experience further increased damage as compared to the airfoil since this material may have different properties. In another embodiment, when the area 105 is located in the fillet 106 , the machining of the modification material 124 (step 160 ) includes a machining of the fillet 106 , which re-contours the fillet 106 and forms a flush surface between the fillet 106 and the modification material 124 . In a further embodiment, the re-contouring of the fillet 106 may increase the radius of the fillet 106 . The increased radius of the fillet 106 may improve a stress resistance of the article 101 . Stress resistance, as used herein, refers to an increased ability to withstand stress without forming increased stress areas.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. | A modification process and modified article are disclosed. The modification process includes locating an area in an article, removing the area by machining to form a machined region, inserting a modification material into the machined region, securing the modification material to the article, machining the modification material flush with a geometry of the article, and applying a coating over at least a portion of the article. Another modification process includes locating an area under a suction side leading edge tip shroud fillet of an airfoil, removing the area by machining to form a hole, inserting a modification material having improved material properties as compared to an original base material into the hole, securing the modification material in place, machining the modification material and the airfoil to form a new fillet contour, and applying a coating over at least a portion of the airfoil. Also disclosed is the modified article. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a dishwasher and more particularly, to a system for supplying heat energy for heating wash liquid in a dishwasher in response to the soil load in the dishwasher.
2. Description of Related Art
Domestic dishwashers in use today draw wash liquid from a sump at the bottom of a wash tub and spray the wash liquid within the wash tub to remove soils from dishes located on racks in the tub. It is well known that the removal of soils from the recirculating wash liquid positively impacts the wash performance of the dishwasher. Accordingly, to improve performance and efficiency, some dishwashers employ a system for separating soil out of the recirculating wash liquid wherein the soils are retained in a collection chamber.
Wash performance in a dishwasher is also related to the temperature of the dishwashing liquid. It is known that hot water is more effective for washing than cold water, particularly for oily soils which melt at higher wash liquid temperatures. Accordingly, dishwashers are commonly connected to a hot water supply such that the fill water supplied into the dishwasher has a relatively high temperature. To further improve performance, some dishwashers allow users to select a heavy wash cycle (sometimes referred to as a Pots & Pans cycle) which provides for the addition of heat energy to raise the temperature of wash liquid during portions of the wash cycle. Such thermal inputs during the dishwasher cycle typically occur during a thermal hold wherein the cycle of operation is interrupted while a heater is energized until a thermostat is satisfied or a maximum default time limit elapses.
Unfortunately, the addition of heat energy to raise the temperature of the wash liquid in a dishwasher only occurs when the user selects a heavy wash cycle, and once selected, thermal energy is added to the wash liquid regardless of actual soil load on the dishes. Accordingly, in some circumstances, heavily soiled dishes do not receive any additional thermal energy input because the operator fails to select a heavy wash cycle. This results in poor wash performance. In other circumstances, dishes which are relatively lightly soiled and do not require additional thermal input are subject to a wash cycle including additional heat energy inputs because the dishwasher operator erroneously selected a heavy wash cycle. This results in unnecessary energy usage.
Accordingly, it would be an improvement in the art if a dishwasher wash system was provided which automatically added heat energy into a dishwasher in response to the soil level of the dishes.
SUMMARY OF THE INVENTION
A thermal input system is provided for a dishwasher having an interior wash chamber receiving soiled dishes and wash liquid. A heater is disposed within a sump region of the wash chamber along with a wash pump which operates to recirculate wash liquid through the wash chamber. A soil collection chamber receives a portion of recirculating wash liquid from the wash pump wherein soils entrained in the wash liquid are captured within the soil collection chamber. A pressure sensor is provided for sensing fluid pressure within the soil S collection chamber. Control means energize the heater during a thermal hold period in response to the pressure within the soil collection chamber exceeding a predetermined limit pressure. In particular, the control means operates to sequence the dishwasher through a predetermined cycle of operation but bypasses the thermal hold period when the pressure within the soil collector does not exceed the predetermined limit pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a dishwasher including an automatic thermal input system in accordance with the present invention.
FIG. 2 is a diametric sectional view of a dishwasher pump used in the dishwashing system illustrated in FIG. 1.
FIG. 3 is a block diagram showing an electrical arrangement of the dishwasher of FIG. 1.
FIG. 4 is a flow chart shown the operation of a dishwasher according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The basic constructional features of the soil separator and pump system of the present invention are disclosed in U.S. Pat. No. 5,165,433, entitled "Soil Separator for a Domestic Dishwasher", herein incorporated by reference. In the '433 patent, the operation of a centrifugal soil separator and the construction of a soil separator and collector are fully explained.
In accordance with the invention as shown in the drawings, and particularly as shown in FIG. 1, an automatic dishwasher generally designated 10 includes an interior tub 12 forming an interior wash chamber or dishwashing space 14. The tub 12 includes a sloped bottom wall 16 which defines a lower tub region or sump 18 (FIG. 2) of the tub. A soil separator and pump assembly 20 is centrally located in the bottom wall 16 and has a lower wash arm assembly 21 extending from an upper portion thereof. Wash liquid may also be supplied to an upper spray arm (not shown). A heating element 22 is disposed within the lower portion of the dishwashing space 14 and may be operated to heat wash liquid within the dishwasher.
Turning to FIG. 2, the soil separator and pump assembly 20 includes a motor 24 suspended below a base plate 28. The motor has an output shaft 26 which extends up through the base plate 28. A drain impeller 30 is fixed to the output shaft 28 and supported within a drain impeller chamber 32 defined by the base plate 28 and a drain cover 36. A wash impeller 38 is drivingly connected to the output shaft 26 and is supported within a pump chamber 40 defined by a pump housing 42 and pump cover 44. An annular soil collection chamber 46 is disposed about the pump chamber 40.
The motor 24 is a reversing motor which normally rotates in a clockwise direction for operating the pump in a recirculation or wash mode. During the wash mode, the wash impeller 38, driven by motor 24, draws wash liquid from the sump 18 through a pump inlet 45, provided between the pump housing 42 and the base plate 28, and pressurizes the wash liquid within the pump chamber 40. The majority of the pressurized wash liquid is directed by diffuser vanes 50 through the pump outlet and is divided between flow to the lower spray arm 21 and flow to an upper spray arm supply tube 52. A portion of wash liquid swirling within the pump chamber 40 and having a high concentration of entrained soils is directed into an annular guide channel 54 and from there into the soil collection chamber 46.
The soil collection chamber 46 is generally defined by the walls 42a and 42b of the pump housing 42 and an upper housing member 47. As wash liquid flows from the annular guide channel 54 into the soil collection chamber 46, the liquid level within the soil collection chamber 46 rises until reaching the member 47. Fine mesh filter segments 56 in the member 47 permit flow of cleansed wash liquid to exit from the soil collection chamber 46 and return to the dishwasher sump region 18. Heavy soils settle within the soil collection chamber and lighter soils are captured by the filter segments 56 such that both heavy and light soils are captured within the soil collection chamber 46.
During the wash cycle, the filter segments 56 are repeatedly backflushed. As the lower wash arm 22 rotates, pressurized wash liquid is emitted from downwardly directed backflush nozzles. Means may be provided for forming a fan-shaped spray from the flow of wash liquid through the backflush nozzles. As the lower wash arm rotates, this fan shaped spray sweeps across the filter segments 56 providing a backwashing action to keep the screen clear of soil particles which may impede the flow of cleansed wash liquid into the sump 18.
In spite of backflushing, in conditions of a heavy soil load, the filter screen segments 56 may become clogged with food soils. When this occurs, pressure within the soil collection chamber 46 increases. This pressure increase is sensed by a pressure sensor 60 which is connected to a pressure dome or chamber 62 via a pressure tap tube 64. As the pressure within the soil collection chamber 46 rises, the air within the pressure dome 62 is compressed and this increase in air pressure is sensed by the pressure sensor 60. The pressure sensor 60 may be a single-pole, double throw pressure switch which is designed to trip or actuate at a predetermined limit pressure P L . The pressure sensor 60 may be mounted to any suitable structure beneath the bottom wall 16 of the dishwasher.
When the actual pressure P A in the soil collection chamber exceeds the predetermined limit pressure P L , indicative of a clogged screen mesh 48, the motor 24 can be reversed from rotating in a clockwise direction to rotating in a counter-clockwise direction. In this reversed direction, the drain impeller 30 operates to drain wash liquid from the dishwasher thereby clearing the soil collection chamber 46 of soils and cleaning the filter screen segments 46. Adrain pump 54 is energized to clear the screen mesh. In response to the pressure within the soil collection chamber 46 exceeding the predetermined limit pressure P L the dishwasher may be completely drained of wash liquid or just partially drained of wash liquid. If only partially drained, the amount of wash liquid drained may be controlled by time or by other means such as draining until the pressure within the soil collection chamber 46 drops below the predetermined pressure limit P L .
Monitoring the pressure within the soil collection chamber 46 may also be beneficially used to control the thermal input into the dishwasher. As described above, it is well known that wash performance is improved by using warm or hot water. It is particularly desirable, therefore, to add heat to the wash liquid within the dishwasher when the dishes being washed are heavily soiled. Accordingly, the present invention provides for adjusting the dishwasher cycle and the addition of heat to the wash liquid in response to the pressure within the soil collection chamber 46 exceeding the predetermined limit pressure.
FIG. 3 illustrates a block diagram of a control system for implementing a thermal hold in response to the soil level of dishes in a dishwasher. A controller 70 is provided comprising of a comparator 72 and memory means 74. The controller 70 is connected to operation switches 76 such that the dishwasher operator can input cycle selections. The controller 70 also receives input from the pressure sensor 60 and from a temperature sensor 78 which may be mounted adjacent the bottom wall 16 for sensing the temperature of wash liquid within the dishwasher (see FIG. 2). Alternatively, and as preferably contemplated, the temperature sensor may be attached to the base plate 28 and have a sensing portion protruding through a hole in the base plate for directly sensing the temperature of the wash water in the dishwasher sump 18. The temperature sensor may be a thermistor or a thermostat. A water valve 80 for supplying water into the dishwasher, the pump motor 24 and the heater 22 are connected to the controller 70 through a driver 82 such that these components can be selectively energized by the controller 70.
Turning now to FIG. 4, the operation of the dishwasher can be explained. Step 84 represents a conventional fill period wherein the fill valve 80 is energized for supplying water into the dishwasher. After water is added to the dishwasher, the motor 24 is energized for recirculating wash liquid throughout the dishwasher in a wash mode as shown in step 86. During this first wash period, a first sensing period, represented by steps 88 and 92, is initiated wherein the controller 70 monitors the pressure sensor 60 to determine whether the actual pressure P A exceeds the predetermined limit pressure P L . In this manner, the pressure within the soil collection chamber 46 is monitored to determine if an excessive quantity of soil is present. During this and subsequent sensing periods, an indicator light 94 (FIG. 3), such as an LED, is energized to provide feedback to the consumer that a soil sensing operation is being executed.
If during this sensing period, the actual pressure P A within the soil collection chamber 46 exceeds the predetermined pressure limit P L , the dishwasher is immediately drained, step 96, followed by a second fill and the initiation of a second wash step, shown at 98 and 100, respectively. During this second wash period, a second sensing period, represented by steps 102 and 106, is initiated wherein the pressure sensor 60 is monitored to determine if the pressure in the soil collection chamber 46 exceeds the predetermined limit pressure P L . If the predetermined limit pressure P L is exceeded, the dishwasher is again immediately drained, step 108, followed by a third fill and the initiation of a third wash step, shown at 110 and 112, respectively.
During the third wash period, a thermal hold step 114 is initiated. During the thermal hold, the heater 22 is energized to heat the wash liquid within the dishwasher. Assuming the temperature sensor to be a thermistor, the output T M of the temperature sensor 78 is compared by comparator 72 with a predetermined setpoint temperature T SP , typically 130° F. to 140° F., stored in memory 74. The dishwasher remains in the thermal hold period until the wash liquid temperature equals the set point temperature T SP or until a default time limit is exceeded. If the temperature sensor is a thermostat, the controller 70 monitors the thermostat during the thermal hold for sensing when the wash liquid temperature is raised to the set point temperature T SP . During the thermal hold period, the pump system 20 continues to recirculate wash liquid over the dishes.
Upon completion of the thermal hold cycle, the dishwasher is drained 116. Subsequently, the dishwasher executes a plurality of fill, recirculate (rinse) and drain steps, shown at 118, to rinse the dishes.
Accordingly, it can be understood that the above described dishwasher operation provides a thermal hold cycle only when a heavy soil load is sensed. Specifically, if during the first sensing period 88 92, the pressure with the soil collection chamber 46 never exceeds the predetermined pressure limit P L , then two fill steps are avoided and the thermal hold period is bypassed. However, if during the first sensing period 88 92, the pressure in the soil collection chamber 46 exceeds the predetermined pressure limit P L , then the thermal hold step is not bypassed. In this manner, heat energy is not added to the wash liquid when the dishes are only lightly soiled.
While the above description includes two sensing periods, it can be readily understood that the present invention is not limited to two sensing periods. The dishwasher cycle could be configured having more than two sensing periods or less than two sensing periods. Specifically, the present invention contemplates a dishwasher cycle having only a single pressure sensing period and wherein a thermal hold is initiated if soils are sensed during that sensing period.
It can be seen, therefore, that the present invention provides a system for bypassing the addition of thermal energy into a dishwasher when the dishes being washed are only lightly soiled. In this manner, the thermal input to the dishwasher is responsive to the soil level of the dishes such that energy is not used unnecessarily. While the present invention has been described with reference to the above described embodiments, those of skill in the Art will recognize that changes may be made thereto without departing from the scope of the invention as set forth in the appended claims. | A thermal input system is provided for a dishwasher having an interior wash chamber receiving soiled dishes and wash liquid. A heater is disposed in a sump region of the wash chamber along with a wash pump which operates to recirculate wash liquid through out the wash chamber. A soil collection chamber receives a portion of recirculating wash liquid from the wash pump wherein soils entrained in the wash liquid are captured within the soil collection chamber. A pressure sensor senses fluid pressure within the soil collection chamber. Control means are provided for energizing the heater during a thermal hold period in response to the pressure within the soil collector exceeding a predetermined limit pressure. In particular, the control means operates to sequence the dishwasher through a predetermined period of operation but bypasses the thermal hold cycle when the pressure within the soil collector does not exceed the predetermined limit pressure. | 0 |
CROSS REFERENCE TO PRIOR ART
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62/029,405, filed Jul. 25, 2014.
TECHNICAL FIELD
[0002] The field discussed herein generally relates to anti-theft devices using Radio Frequency Identification (“RFID”).
BACKGROUND
[0003] Retailers suffer substantial losses related to the theft of consumer goods composed of fluids. Currently, most retailers rely on anti-theft devices to secure these goods, most using RFID that employ RFID-Tags that are affixed to the consumer goods. Upon activation the embedded microchip emits and receives radio frequencies, which are transmitted to and from antennae situated at the entrance and exit of a store. If a thief attempts to asport the goods out of the store, the RFID-Tag's embedded microchip determines a differential in the radio frequencies and relays a signal to the antenna sounding an alarm.
[0004] However, retailers find the efficacy of RFID limited, as thieves increasingly use booster bags to stifle the technology. When a thief places the consumer goods equipped with an RFID-Tag in a booster bag, the bag's aluminum lining prevents the RFID-Tag's embedded microchip from emitting and receiving radio frequencies and thus sounding the alarm. Given the ease with which thieves can use booster bags to steal these goods, and the ease by which thieves can then resell them as they still are usable, thefts remain rampant.
[0005] Instead, retailers have been forced to dilute the retail experience by employing physical barriers, which prevent customers and thieves alike from accessing these goods, like glass cases that are locked. To solve this problem, most innovation in anti-theft technology has focused circumspectly on empowering retailers to detect thieves with booster bags using booster bag detecting scanners stationed adjacent to the antennae at the entrance and exit, rather than deterring thieves from using booster bags in the first place by making the goods they might otherwise be able to steal using the bags unusable when asported.
[0006] The foregoing examples of the related art and limitations inherent therein are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent upon a reading of the specification and a study of the drawings.
SUMMARY
[0007] The following examples and aspects thereof are described and illustrated in conjunction with systems, tools, and methods that are meant to be exemplary and illustrative, not limiting in scope. In various examples, one or more of the above-described problems have been reduced or eliminated, while other examples are directed to other improvements.
[0008] As discussed herein, retailers may benefit from consumer goods composed of fluids with a RFID Tag with Neutralizing Actuator(s) that is discreetly inserted into the product and when armed and signaled, releases a neutralizing agent that renders component fluids unusable.
[0009] The RFID Tag with Neutralizing Actuator(s), including advancements disclosed herein, enjoys a discreet design, allowing it to be placed within consumer goods without affecting presentation but that is innovatively equipped to receive a signal that releases a neutralizing agent into the good's component fluid to make it unusable if asported.
[0010] Herein is described a RFID Tag with Neutralizing Actuator(s) consisting of a RFID-Tag, Hardwired Logic Circuit with specific logic, a battery, neutralizing agent, actuator(s) and other components.
[0011] The embodiment of the RFID Tag with Neutralizing Actuator(s) encompasses a compartment, which may be cylindrical, with a closed vertical space through the center in which the RFID-Tag, Hardwired Logic Circuit, the battery, neutralizing agent, actuator(s) and other components are affixed. Advantageously, this provides a novel way for it to be to discreetly attach it to consumer goods, by placing it in a container with a fluid dispenser that is inserted directly into the fluids
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1A-C depicts a retail store where consumer goods have been affixed with RFID Tags with Neutralizing Actuator(s), which are armed or disarmed by a hand-held scanner to correspond with antennae at the entrance/exit.
[0013] FIG. 2 depicts a consumer good composed of fluid, housed in a bottle with a fluid dispenser, affixed with the RFID Tags with Neutralizing Actuator(s).
[0014] FIGS. 3A-B depicts the RFID Tags with Neutralizing Actuator(s), and its components.
[0015] FIG. 3C depicts how the RFID-Tag and Hardwired Logic Circuit relates to the actuators and pin switch.
[0016] FIG. 4 is a schematic of the Hardwired Logic Circuit logic.
DETAILED DESCRIPTION
[0017] In the following description, details are presented to provide a thorough understanding of the invention. One skilled in the relevant art will recognize, however, that the concepts and techniques disclosed herein can be practiced without one or more of the specific details, or in combination with other components, etc. In other instances, well-known implementations or operations are not shown or described in detail to avoid obscuring aspects of various examples disclosed herein.
[0018] “Above” means in a higher place than the compartment, which houses the RFID-Tag.
[0019] “Armed” means the state of the RFID-Tag in which the Hardwired Logic Circuit will permit execution of an initiate release signal.
[0020] “Adjacent” means contiguous to the antennae located in the store.
[0021] “Affix” means to fasten or attach.
[0022] “Alarm” means an automated sound that serves to signal the retailer to a theft or call attention to a theft.
[0023] “Antennae” mean conductors by which electromagnetic waves or radio frequencies are sent out or received.
[0024] “Anti-theft Device” means any contrivance designed to prevent theft.
[0025] “Asport” means to take the property of a retailer without permission with the intent to deprive the retailer of dominion.
[0026] “Authentication Protocol” means the rules designed to ensure the genuineness of a signal.
[0027] “Battery” means a combination of two or more cells electronically connected to work together to produce electrical energy.
[0028] “Booster Bag” means a bag used by thieves, with an aluminum lining that prevents consumer goods equipped with a RFID-Tag inside from sending or receiving signals.
[0029] “Ceiling” means the overhead interior non-conductive filler surface of the compartment which houses the RFID-Tag.
[0030] “Circuitry Lead” means an electrical connection consisting of a length of wire or metal pad used as physical support to transfer power to the RFID-Tag's circuits.
[0031] “Circular” means having the form of a circle or round.
[0032] “Closed” means having or forming a boundary or barrier.
[0033] “Compartment” means the closed partitioned space that houses the RFID-Tag.
[0034] “Component” means a constituent part of the consumer good.
[0035] “Concentric” means having a common center.
[0036] “Consumer Good” means goods that are ready for consumption by humans that are composed of fluids.
[0037] “Convey” means to communicate with.
[0038] “Disarmed” means the state of the RFID-Tag in which the Hardwired Logic Circuit will not permit execution of an initiate release signal.
[0039] “Deactivate” means to cause to be inactive by rendering a signal.
[0040] “Embedded” means affixed to the circuit or fastened to it or programmed within it.
[0041] “Enclosed” means closed in all sides.
[0042] “Entrance” means a point or place of entering.
[0043] “Exit” means a way or passage out.
[0044] “Externally” means of or pertaining to the outside of the compartment in which the RFID-Tag is housed.
[0045] “Floor” means the bottom level of the compartment housing the RFID-Tag.
[0046] “Fluid” means a substance, as a liquid, that is capable of flowing and that changes shape at a steady rate when acted upon by a force tending to change its shape.
[0047] “Glued” means joined or fastened with glue.
[0048] “Groove” means a long, narrow indentation in the surface.
[0049] “Hand-held Scanner” means a device held by hand used to read information off or send commands, such as arm and disarm, to the RFID Tag with Neutralizing Actuator(s).
[0050] “Hardwired Logic Circuit” means a circuit that does a logic check such as a microchip, microprocessor, microcontroller, Application Specific Integrated Circuit (“ASIC”) and Field-Programmable Gate Array (“FPGA”) which is integrated within the RFID-Tag or externally coupled with the RFID-Tag.
[0051] “Hole” means an opening through something, such as a gasket.
[0052] “Instructions” means information imparted to the RFID-Tag about what it should transmit.
[0053] “Instruct” means to furnish with orders or directions.
[0054] “Interior” means the portion of the compartment housing the RFID-Tag that is within.
[0055] “Lateral” means of or pertaining to the side.
[0056] “Lead” means a structure to provide physical support by delivering electrical currents to a device.
[0057] “Liquid Proof Coating” means a coating added to the shape memory alloys to make them liquid resistant.
[0058] “Logic” means the system or principles of reasoning applicable to the Hardwired Logic Circuit and how it functions.
[0059] “Logic Check” means the process by which the Hardwired Logic Circuit applies a system or principles of reasoning to check for specific filters.
[0060] “Modified” means significantly changed.
[0061] “Neutralizing Agent” means the substance that is released to make the consumer good's component fluid unusable.
[0062] “Non-conductive Filler Substance” means a substance that does not conduct electrical currents and is used to fill any gaps between the ceiling and floor of the compartment that houses the RFID-Tag and the rest of the compartment.
[0063] “Emit” means to send a signal.
[0064] “Opening” means a void or gap in space.
[0065] “Past” means to be located behind something.
[0066] “Pin Switch” means a switch that causes a temporary change in the state of the switch circuit only while the switch is manually actuated.
[0067] “Protrude” means to project outward from the interior of the compartment that houses the RFID-Tag.
[0068] “Radio Frequency Identification (“RFID”)” means the technologies that use radio waves to automatically identify objects or people.
[0069] “RFID-Tag” means an electronic device composed of a microchip that communicates via radio frequencies with an antenna.
[0070] “Radio Frequency” means the frequency of transmitting waves of a given radio transmission.
[0071] “Receive” means to take in a signal.
[0072] “Release” means to emit the neutralizing agent.
[0073] “Space” means an area in two dimensions of a particular extent of surface.
[0074] “Fluid dispenser” means a complex instrument designed to scatter the fluids into the air in the form of fine particles or otherwise dispense of the liquid from the container.
[0075] “Dispenser cap” means a close-fitting covering of the fluid dispenser.
[0076] “Transmit” means to send a signal.
[0077] “Tubing” means a hollow cylindrical body of material used to channel fluids which is attached to the dispenser cap.
[0078] “Unusable” means serving no purpose to the thief.
[0079] “Validate” means logical confirmation of filtered information using established system and protocols of logical reasoning.
[0080] “Vertical” means being in a position perpendicular to the plane of the horizon.
[0081] “Wall” means the permanent upright sides of the compartment housing the RFID-Tag.
[0082] As affixed to consumer goods made with fluids, a modified RFID-Tag when activated, and when signaled or asported, releases a neutralizing agent that renders component fluids unusable, is realized by enveloping a series of actuator(s). A RFID-Tag with a Hardwired Logic Circuit with the teachings provided herein can be used to exploit actuator(s) to facilitate the release of a neutralizing agent into the fluid portion of the consumer good.
[0083] Shown in FIG. 1A is a retail store where consumer goods have been affixed with RFID Tags with Neutralizing Actuator(s). The retailer is holding a hand-held scanner ( 102 ); all of the consumer goods have been affixed with RFID Tags with Neutralizing Actuator(s) ( 108 ). The RFID-Tags emit and receive radio frequencies to and from the antennae ( 106 ) located at the entrance/exit.
[0084] FIG. 1B depicts a consumer good composed of fluid, housed in a bottle with a fluid dispenser, affixed with a compartment that houses a RFID-Tag with Neutralizing Actuator(s) ( 208 ). The retailer uses a hand-held scanner ( 202 ) to transmit an authentication protocol to the RFID-Tag; the RFID-Tag receives the authentication protocol and conveys it to the Hardwired Logic Circuit, which uses embedded logic to confirm it and convey a signal back that it is ready to receive instructions. The retailer then uses the hand-held scanner to transmit instructions to the RFID-Tag. The retailer can transmit a signal to the RFID-Tag to either arm or disarm it. If the RFID-Tag is armed, when a thief attempts to asport the consumer good to which it is attached, when the consumer good comes within range of antennae the RFID-Tag will receive an initiate release signal. When the RFID-Tag receives the signal, its Hardwired Logic Circuit validates the signal and then initiates a countdown that if completed will trigger a release of the compartment bottom half into the consumer good's component's fluids, rendering the fluid unusable. If the retailer disarms the RFID-Tag, it will deny initiate release signals from the antennae. The retailer can also transmit a signal to the RFID-Tag requesting information about the consumer good to which it is attached, such as (1) when the consumer good was manufactured, (2) where the consumer good was manufactured, or (3) what the good's transactional history has been.
[0085] FIG. 1C shows what happens at the retail store when a thief asports the consumer good ( 308 ) affixed with the RFID-Tag with Neutralizing Actuator(s) that has been armed by a retailer with a hand-held scanner ( 302 ) past the antennae at the entrance/exit. The RFID-Tag receives an initiate release signal from the antennae ( 306 ) when the RFID-Tag comes within proximity of the antennae. When the RFID-Tag receives the signal, its Hardwired Logic Circuit validates the signal and then initiates a countdown that if completed will trigger a release of the compartment bottom half into the consumer good's component's fluids, rendering it unusable.
[0086] FIG. 2 shows a consumer good composed of fluid, housed in a bottle ( 410 ). The bottle has a fluid dispenser comprised of a dispenser cap at the top ( 414 ) which is attached to tubing that may be cylindrical that extends downward into the fluid ( 412 ). The tubing passes through a RFID Tag with Neutralizing Actuator(s) ( 408 ) via a lateral circular opening. The dispenser cap dispenses the fluid after it is pumped to the cap through the tubing.
[0087] The consumer good when housed in a bottle has a fluid dispenser whose tubing can be easily run through a compartment that may be cylindrical with an enclosed vertical center. FIGS. 3A-B depicts the compartment that houses the RFID-Tag with Neutralizing Actuator(s) and its components.
[0088] FIG. 3A shows the compartment ( 508 ) with an enclosed vertical center ( 548 ), RFID-Tag ( 518 ), Hardwired Logic Circuit ( 516 ), pin switch ( 526 ), insert ( 536 ), and a battery ( 520 ). The bottom face of the insert ( 536 ) rests in a notch above a hole in the base of the compartment ( 508 ). Located on the compartment's interior wall, the RFID-Tag ( 518 ), Hardwired Logic Circuit ( 516 ), battery ( 520 ), and pin switch ( 526 ) and are all connected to each other by electrical wires ( 1072 ) and are glued to the wall and covered by non-conductive filler substance. The piston of the pin switch ( 526 ) protrudes above the top of the compartment and is connected to the dispenser cap ( 414 ).
[0089] FIG. 3B shows the insert ( 536 ) comprising the top cap ( 660 ), top tube ( 662 ), firebreak ( 664 ), capsule holder ( 666 ), shape memory alloys ( 670 ), and two electrical wires ( 672 ). The top tube ( 662 ) is a hollow cylinder. The top cap ( 660 ) is a thin cylindrical lid that covers the top tube ( 662 ) and secured together by glue. The top tube ( 662 ) is notched to allow the two electrical wires ( 672 ) to run through it. The firebreak ( 664 ) is a thick cylindrical lid that has small vertical slits ( 674 ) within it that allow for the shape memory alloys ( 670 ) to pass through it and is secured to the bottom of the top tube ( 662 ) by glue. The capsule ( 680 ) that is cup shaped is connected to the interior of the capsule holder ( 666 ), which is hollow and cylindrical in shape, by tabs ( 682 ). Above the capsule holder ( 666 ) and vertically aligned with the tabs ( 682 ) are an equal number of slits ( 674 ) in the firebreak ( 664 ). Two electrical wires ( 672 ) runs through the notches of the top tube ( 662 ). Length(s) of shape memory alloys ( 670 ) run from one electrical wire ( 672 ) down through the slits in firebreak ( 664 ) and around its respective tab ( 682 ) and back up to the other electrical wire ( 672 ). The capsule holder ( 680 ) is secured to the bottom of the firebreak ( 674 ) by glue. The open face of the capsule ( 680 ) within the capsule holder ( 666 ) is flush with the bottom of the firebreak ( 664 ), which seals the encapsulated neutralizing agent.
[0090] When the fluid dispenser is depressed by pressing the dispenser cap, the pin switch ( 526 ) is also depressed, thus completing the switch circuit. Upon such manual activation of the pin switch ( 526 ), the Hardwired Logic Circuit ( 516 ) does a logic check.
[0091] As reflected in FIG. 3A but shown in more detail in FIG. 3C , extending from the Hardwired Logic Circuit ( 1016 ) are pins ( 1090 ); some of the pins connect to the pin switch ( 1026 ), some of the pins connect to shape memory alloys ( 1070 ), while the other pins connect to the RFID-Tag ( 1018 ) and the battery ( 1020 ).
[0092] FIG. 4 shows the Hardwired Logic Circuit logic. If the RFID-Tag ( 518 ) is armed, then the Hardwired Logic Circuit logic will determine if there is any initiate release signal. If the RFID-Tag receives an initiate release signal from either (i) antennae, such as those at the store's entrance or exit, or (ii) the switch circuit, upon manual activation when the pin switch ( 526 ) is depressed and the switch circuit is complete, then the Hardwired Logic Circuit does a logic check. If the initiate release signal originated from the antenna, then the Hardwired Logic Circuit logic will determine if a valid release instruction has occurred, and a timer will begin counting down ( 956 ); when the timer reaches zero (0), the logic determines that a release is authorized. The bottom compartment is released when the Hardwired Logic Circuit logic permits the battery to send an electrical current into the shape memory alloys. When an electric current is applied to the shape memory alloys ( 670 ) by way of the electrical wires ( 672 ), the shape memory alloys ( 670 ) contract upwards. The tabs ( 682 ) are broken by the force of the contraction of the shape memory alloys ( 670 ). However, the firebreak ( 664 ) prevents the shape memory alloys ( 670 ) from breaking other parts of the insert ( 536 ). When the tabs ( 682 ) break, the capsule ( 680 ) drops into the fluid ( 412 ).
[0093] Upon dropping into the liquid product, the neutralizing agent contained in the capsule then mingles with the liquid product until it is rendered unusable. If the RFID-Tag receives a terminate release signal, such as from a hand-held scanner, the Hardwired Logic Circuit resets the device to armed state default. If the initiate release signal originated from manual activation of the RFID-Tag's switch circuit, the battery sends an electrical current into electrical current into the shape memory alloys. Upon dropping into the liquid product, the neutralizing agent contained in the contained in the capsule then mingles with the liquid product until it is rendered unusable. If the device is disarmed, then the Hardwired Logic Circuit will deny any initiate release signal. The result is that the tabs connecting the capsule to the capsule holder remains intact and the capsule remains locked in the insert.
[0094] It will be appreciated to those skilled in the art that the preceding examples and embodiments are exemplary and not limiting to the scope of the present invention. It is intended that all permutations, enhancements, equivalents, and improvements thereto that are apparent to those skilled in the art upon a reading of the specification and a study of the drawings are included within the true spirit and scope of the present invention. It is therefore intended that the following appended claims include all such modifications, permutations and equivalents as fall within the true spirit and scope of the present invention. | By modifying a RFID-Tag, with a Hardwired Logic Circuit and by incorporating actuator(s), its efficacy for preventing theft of consumer goods composed of fluids is improved by bypassing efforts made by thieves to deter RFID detection and making the consumer goods they may otherwise take unusable by neutralizing the component fluids. | 6 |
[0001] This application claims the benefit of our U.S. provisional patent application with the Ser. No. 60/694,024, which was filed Jun. 23, 2005.
FIELD OF THE INVENTION
[0002] The field of the invention relates to the transmission of power by gears.
BACKGROUND OF THE INVENTION
[0003] When gas turbine or turboshaft engines are employed to drive a plant, machinery, or a vehicle, a high numerical reduction ratio is frequently needed because of the output speed of the turbine. In addition, power transmission of several thousands of horsepower is encountered in many applications. In the case of a stationary plant, or for marine applications, mechanical reliability can be readily achieved if the weight of the gearbox is not important. However, with propeller drives for aircraft or rotor drives for helicopters, weight of the gearbox is critically important. This requirement led to the widespread adoption of planetary or epicyclic gearboxes in flight applications. Planetary gearboxes achieve their weight advantage over simple gear trains of the same ratio by virtue of increasing the number of mesh points, and hence load-carrying gear engagements, in a given circumferential length of gearing.
[0004] With increasing scale and power transmission capacity, the weight of a gearbox increases approximately as a cube function of linear size because the steel elements of the gears span the entire radial distance from the center of rotation to the periphery of the largest gear, usually a ring gear. The tangential force resisting a torque is inversely proportional to the distance from the center of rotation, thus it is clear that whilst gear tooth loading from tangential force decreases with radius, weight increases disproportionately.
[0005] Efforts to improve the weight to torque/speed ratio are illustrated by the trend lines for the world population of aircraft and rotorcraft gearboxes in FIG. 10 , in which weight on the vertical axis is plotted against a torque-speed equation on the horizontal axis. Here, the data were taken from approximately 70 different helicopters for a linear fit and included transmissions, rotor shaft(s), lubrication, and rotor brake. When corrected by a calendar year ‘technology factor’, the trend lines are remarkably linear (the technology factor takes into account the material, manufacturing, and lubricant improvements over a time span). For example, the top line in the graph of FIG. 10 is the trend for 1980 technology, while the middle line represents the corresponding trendline at a time 10 years later (i.e., for the year 2000 technology). A projected trendline for the year 2010 is depicted as the bottom line in FIG. 10 . Therefore, desirable gearboxes will advantageously be situated below the 2000, and more preferably below the 2010 trendline with respect to their weight to torque/speed ratio. The performance of an aircraft, equipped with such gearbox, will therefore benefit by increased range or payload from the reduction of the empty weight fraction achieved by a lighter gear box arrangement.
[0006] Therefore, it should be readily apparent that the problem of gearbox specific weight per horsepower constantly recurs in aircraft designs and hence requires a solution. Consequently, there is still a need to provide improved gearboxes, and especially light-weight gearboxes for airplanes and other weight-critical uses.
SUMMARY OF THE INVENTION
[0007] The inventive subject matter provides devices and methods in which gearboxes combine a high numerical reduction ratio with the capability of transmitting power at a power-to-weight ratio previously unattainable with existing designs. A significant advantage is that such devices and methods lessen the importance of compactness or space savings.
[0008] These objectives are achieved with a compound star planetary gearbox which is radially expanded by using hollow driveshafts to link the planet gears. A compound planetary gear arrangement is defined as one where planets of different diameter are torsionally connected to each other, or mesh with each other. The star arrangement refers to the fact that the input and output gears (the sun and ring gear respectively) counter-rotate while the planets rotate in bearings anchored to a static casing. This distinction between star and conventional planetary sets is important as the described approach is based on the principle of radially expanding the planets and supporting them by bearings in machine structure. In contrast, in heretofore known planetary gear arrangements, the planet axes are parallel to the input and output shafts and the planet gear pairs are co-joined or made of common material.
[0009] In the contemplated methods and devices, the planet axes are disposed radially outwards at an angle to the common axis of the input and output shafts, and the individual planet gears are separated by a distance and connected by tubular shafting. The torque carrying capacity of thin wall, tubular, high-strength materials is well known. Torque, and hence the tangential force applied to the ring gear (the output), is transferred to a large radius by means of the radially-located tubular shafts. The result is a high numerical ratio between the small diameter planets and the large ring gear. This large ring gear can be configured with the teeth on the inside or outside of the ring. In either case the result is very high power transmission capacity because of the large radius of application of relatively modest tangential forces.
[0010] This arrangement is especially suited to the driving of large propellers for turboshaft aircraft, or the rotors of large helicopters, because the space or volume constrains are of lesser importance than the weight of the assembled unit. A full assembly consists of a dividing gear set, which is the sun gear and first planets of the compound planet arrangement, and a combining gearbox which consists of the second planets and the output ring gear. In small scale, the dividing and combining gearbox sections and the interconnecting shafts could be co-located in a single housing, but in large scale aircraft or helicopters the separation of the two basic assemblies provides further advantages regarding immunity to structural deflections, drive redundancy, damage tolerance, access improvement, serviceability and weight reduction which are further discussed in detail.
[0011] Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWING
[0012] FIG. 1 is a schematic of arrangements with two (or alternatively three) distributing shafts and two (or alternatively three) pinions, and either an internally- or externally-toothed ring gear.
[0013] FIG. 2 is a schematic of arrangements with two and three distributing shafts, and four and six compounded pinions, and either an internally- or externally-toothed ring.
[0014] FIG. 3 is a schematic of an arrangement with a non-meshing torque divider between two input sun gears, six distributing shafts, and 12 compounded pinions.
[0015] FIG. 4 is an axial cross-section of a single distributing shaft that would be used in accordance with the gearbox of FIG. 1 .
[0016] FIG. 5 is an axial cross-section of a single distributing shaft that would be used in accordance with the gearbox of FIG. 2 .
[0017] FIG. 6 is an axial view showing the driving planet of FIG. 2 in force balance between two driven face gears.
[0018] FIG. 7 is an axial view showing the driving sun gear of FIG. 2 in force balance among three driven face gears.
[0019] FIG. 8 is a cross-section of the mutual support bearing arrangement between the output pinion and the output ring gear.
[0020] FIG. 9 is a partial perspective end view of a possible connection between an output ring gear and the load (or input device) consisting of a series of tangential links.
[0021] FIG. 10 is a graph depicting trendlines for weight to torque/speed ratio for various time periods.
DETAILED DESCRIPTION
[0022] In the figures, the input sun gear is a parallel pinion, axially and radially located at a point remote from the operating plane of the pinion, but with angular freedom such that the pinion can occupy the precise position whereby it is in balance between the tooth contact forces.
[0023] In FIG. 1 , a reduction gearbox 100 generally comprises a radially expanded compound planetary gear set 110 in a casing 115 , that has a distributor portion 120 and a combining portion 130 . The distributor portion 120 generally comprises a sun gear 121 and several planet gears 122 . The combining portion 130 generally comprises a driven ring gear 131 a further set of driving pinions 132 . Connecting the distributor portion 120 and the combining portion 130 is an arrangement of multiple shafts 140 held in bearings 149 .
[0024] Inclination 150 of the connecting shafts 140 relative to the principal axis of an input is a design choice. A larger angle (>45 deg.) results in relatively short assembly, however, this also provides relatively unfavorable gear proportions. Conversely, a shallow angle of inclination lengthens the gearbox, but provides relatively more favorable gear proportions. The same is true of the embodiment in FIG. 2 below. Most preferably, the axes of rotation are fixed relative to the casing.
[0025] FIG. 2 shows an embodiment of a gearbox 200 having a further division of torque by arranging two output planets 242 per drive shaft 240 . By analogy with elements of FIG. 1 , the gearbox 200 generally comprises a radially expanded compound planetary gear set 210 that has a distributor portion 220 and a combining portion 230 . The distributor portion 220 generally comprises a sun gear 221 and several planet gears 222 . The combining portion 230 generally comprises a driven ring gear 231 a further set of driving planets 232 . Connecting the distributor portion 220 and the combining portion 230 is an arrangement of multiple shafts 240 . The arrangement in FIG. 2 uses the load sharing principle of one pinion 241 in force balance between two planets 242 , and therefore the pinions 241 do not require bearing support.
[0026] In FIG. 3 , a reduction gearbox 300 generally comprises a radially expanded compound planetary gear set 310 that has a distributor portion 320 and a combining portion 330 . The distributor portion 320 generally comprises two sun gears 321 A, 321 B that mesh with a first set of several planet gears 322 A, and a second set of planetary gear 322 B, respectively. The combining portions are as shown in figure two, except the quantity is doubled. There is now a first combining portion 330 A which generally comprises a driven ring gear 331 and driving planets 332 A, and a second combining portion 330 B which generally comprises the same driven ring gear 331 and driving planets 332 B. Connecting the distributor portion 320 and the combining portion 330 is an arrangement of multiple shafts 340 .
[0027] Those skilled in the art will, of course appreciate that the arrangements of FIGS. 1 , 2 , and 3 can be driven in reverse. Thus, instead of the gearbox being used to achieve a speed reduction, the gearbox could be used in reverse to achieve a speed increase. Speed increases, for example, can be useful in transferring energy from a low speed windmill to a high speed generator. It is still further generally preferred that the sun and ring gears are configured to achieve a multiplication of at least 10, more typically at least 30, and most typically at least 50.
[0028] Whereas gears and bearings are traditionally fabricated from high strength steel, the connecting shaft 140 in FIG. 4 , is preferably constructed of a carbon fiber filament or tape with a resin binder, in a thin walled tubular configuration. Also shown are pinion bearings 149 , and the driving planets 132 . Interconnection member 148 is joins the tubular shaft 140 to driving pinion 132 . The connecting shaft 240 of FIG. 5 is also advantageously comprised of a carbon fiber filament or tape with a resin binder, in a thin walled tubular configuration. Here, however, instead of pinion bearings at both ends, the shaft is mutually supported by the driven planetary gears 332 A at one end, and pinion bearings 149 at the other end. In both FIGS. 4 and 5 , the shaft length and other dimensions are determined by installation requirements, and is also dependent upon the angle of inclination 150 . Flexible bellows 249 allows gear 232 to adopt its force-balanced running position.
[0029] In FIG. 6 , an end of a driving planet 234 is shown meshing with driven face gears (planets) 233 and is in force balance. The face gears 233 are preferably identical to each other to equally divide the torque.
[0030] In FIG. 7 , an end of a driving sun gear 221 is shown meshing with three driven face gears (planets) 222 and is in force balance. Here again, the face gears 222 are preferably identical to each other to equally divide the torque.
[0031] In FIG. 8 , a bearing connection arrangement 800 generally comprises a caliper 810 , a pinion 830 , pinion bearings 839 , a ring gear 840 , and ring gear bearings 819 . Those skilled in the art will appreciate that the caliper 810 should provide a rigid connection between the bearings 839 and 819 . In other respects, namely the relationship between the dividing and combining portions, this is a deflection-tolerant gearbox.
[0032] In FIG. 9 , output ring gear 840 is coupled to the load (or input device) 850 by a series of links 860 . Links ends preferably comprise compliant connections allowing angular deflection to occur between members 850 and 860 . As is commonly configured with flexible links, links 860 are preferably terminated with an integral clevis connected to ball 862 . Flexibility in the connection is advantageous because it isolates the torque from any externally applied forces.
[0033] Meshing with the input sun gear are three face gears, otherwise referred to as the first compound planet gears. These are supported in bearings mounted in gearcase structure, and are connected to radial driveshafts, which are preferably of tubular construction. The radially-outboard end of the driveshaft is connected to a further parallel pinion, referred to as the second compound planet gear. This either drives the ring gear directly, ( FIG. 1 ) in which case the pinion is supported in bearings, or, drives the ring gear through further compounding using two face gears and two further pinions. ( FIG. 2 ) In such arrangement, the second compound pinion is free to occupy the precise position whereby it is in force balance. The driveshafts, which are intended to run in a dry environment in the larger scale gearboxes, operate within containment tubes designed to protect the shafts from outside impact events, or minimize collateral damage in the event of shaft failure.
[0034] The large-diameter ring gear, being conical, is a face gear and because it is internally toothed, produces a mesh geometry exhibiting a high contact ratio which is beneficial for stress reduction. The ring gear rotates in an annular housing and is supported on rolling element bearings, or, in an alternative arrangement, rotates in plain bearings. The stationary housing is mounted on and reacts torque to the machine structure. The output drive is transmitted from the ring gear to the load by multiple points of connection, preferably at a large radius from the center of rotation in order to minimize tangential forces. It will be seen from FIG. 1-3 that the output ring gear is a true annulus, which allows structure or other machine elements, to pass through the center. The gear lubricating oil is contained using lip seals, contacting both the internal and external surfaces of the annular gear.
[0035] As the gearbox size and transmitted power increase, the number of driveshafts is likely to increase from three to six, with two input sun gears being employed, the first with three first compound planets arranged symmetrically at 120 Deg. intervals and the second similar arrangement displaced 60 Deg. to the first so the driveshafts are positioned with operating clearance from the rims of the first planet gears ( FIG. 3 ). Note that the axes of all radial shafts converge at the same intersection point on the input/output center line of rotation. This geometry is beneficial in that it allows a set of identical combining gear arrangements at the ring gear perimeter housing with consequent common components and dimensions.
[0036] A feature common to all preferred embodiments is that input torque is distributed to and divided equally between the final pinion-to-ring gear mesh points. This allows accurate prediction of the gear and bearing loading cases with subsequent confidence in the life and reliability calculations.
[0037] Another feature of great importance when the design is integrated into lightweight aircraft structure is the gearbox tolerance to load-induced deflections. It will be seen from FIG. 1-3 that the distributing and combining sections of the arrangement are independently sealed, separately-mounted, rigid sub-assemblies containing independent lubrication supplies. This is important when considering the redundancy opportunities, the fail-operational characteristics and tolerance to damage from ballistic impact.
[0038] FIG. 3 shows a particular feature providing drive redundancy. The non-meshing torque divider will provide free balance of power between both input sun gears, yet if drive is lost in one “branch” of the connected system such as would be caused by a shaft, gear or bearing failure or by externally-caused damage, the divider locks into one of two end default positions and drive through the active branch is maintained.
[0039] The diverging driveshafts each occupy a radial locus on the surface of a cone whose angle to the input/output centerline lies between a shallow and steep limit of approximately 20 and 50 Deg. respectively. If shallow, the driveshafts are long and heavier, but the face gears can alternatively be built with more face width (for more torque capacity) or less ratio (for higher speed and hence lighter driveshafts). If the cone angle is steep, the overall dimensions of the transmission are reduced, but the gear face decreases and the pinion/face gear pairs have to be run with more ratio in order to mesh correctly, thus slowing down the driveshafts and increasing their weight. These variables can be adjusted by mathematical analysis to produce a balanced design with optimum power to weight performance.
[0040] High strength tubular driveshafts constructed in composite materials offer an optimum torque-to-weight relationship. Because these lightweight members are the torque transfer medium to the large diameter ring gear, the steel content of the overall gearbox components, when expressed against outside dimensions and torque capacity, is much reduced compared with prior-art planetary and load-sharing gearboxes. This result has useful life and reliability implications. Some of the potential weight saving can be re-invested in the actual gear tooth sections and face widths and in the bearing proportions, reducing the loads and extending the gearbox life. This gearbox configuration would therefore find application in man-rated aircraft and helicopter applications, where extreme reliability is called for. The table below indicates the expected correlation between ring gear diameter and torque in contemplated devices and methods, wherein the devices will consistently and reliably transfer torque. In low-torque devices (e.g., unmanned aircraft), it is generally contemplated that torque is less than 5,000 ft-lb, while in manned aircraft, torque is preferably at least 50,000, more preferably at least 100,000, and in some cases even more than 500,000 ft-lb.
[0000]
torque (ft-lb)
5000
50,000
100,000
500,000
ring gear dia.
12
30
45
68
(in)
[0041] Therefore, it should be appreciated that various advantages of contemplated devices and methods are achieved by radially expanding a compound star planetary gearbox by extending the torque-carrying connection between the planet gears. Moreover, by separating the dividing and combining elements of the gearbox, deflection-tolerance can be substantially improved. Still further, it should be appreciated that dividing the power transmission paths provides redundancy and hence fail-operational ability. In a yet further advantageous aspects, minimum-weight connection is achieved by attaching the driven load to the ring gear near gearbox outer diameter by multiple links. Using such and other torsionally stiff and weight efficient connections, the inventor calculated that contemplated devices exhibit a torque to weight ratio of greater than a projected 2010 parametric norm for lightweight high torque gearboxes (i.e., will be positioned below the bottom line of the graph in FIG. 10 ).
[0042] Thus, specific embodiments and applications of light-weight gearboxes, and especially light-weight reduction gearboxes have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. | Contemplated gearboxes combine a high numerical reduction ratio with the capability of transmitting power at a superior power-to-weight ratio using a compound star planetary gearbox configuration that is radially expanded using hollow driveshafts to link the planet gears. In most preferred compound planetary gear arrangements, planets of different diameter are torsionally connected to each other, or mesh with each other. Input and output gears counter-rotate while the planets rotate in bearings anchored to a static casing. | 1 |
BACKGROUND OF THE INVENTION
Field of the Invention
This application relates generally to the field of solid rocket propellants. More particularly, the invention pertains to the reduction of halogen acids in the combustion exhaust plume from solid rocket propellants containing ammonium perchlorate or other halogen containing materials.
State of the Art
Solid rocket propellants containing ammonium perchlorate or other halogenic components may produce large quantities of acids, e.g. hydrochloric acid, which appear in the exhaust plume. For example, each space shuttle flight has consumed about 773 tons of an oxidizer ammonium perchlorate in the booster rockets. Approximately 230 tons of free hydrochloric acid (HCl) immediately appears in the exhaust from such flights. Thus, about 95 percent of the total quantity of perchlorate is converted to HCl, and the products of combustion comprise nearly 20 percent HCl by weight. Some of the hydrochloric acid is subsequently converted to non-acid forms, e.g. aluminum chloride, but about 55+ percent remains as acid.
The acid produced is a serious hazard to the health of persons in the immediate vicinity and downwind from the launch site. In addition, the acid is extremely corrosive and produces rapid deterioration of the launch facilities and other structures which are downwind. Long-term harmful effects are also produced in the indigenous plant and animal life of the area.
Recognizing the deleterious environmental and health effects of the acidic plume, the government has proposed that non-halogen containing oxidizers be developed for use in large rocket systems replacing the ammonium perchlorate (AP). All substitutes to date have been unsatisfactory from the standpoints of mechanical properties, ballistic properties, ease of production, and/or safety. Desirably, the new propellant will (a) result in halogenic plume acids less than 5 percent of that produced by current generation motors; (b) be no more difficult to prepare, mold and cure than currently used space shuttle solid rocket propellants; (c) perform ballistically as well as or better than current propellants in terms of specific impulse Isp, burn rate and efficiency; (d) have the required structural properties for consistent combustion and safety; (e) be capable of having its burn rate readily tailored over a wide range; (f) have ignition characteristics of a Class 1.3 hazard, i.e. a 0-card goal; and (g) be low in cost. In addition, long-term stability of the propellant is required.
The current state-of-the-art reduced acid propellant uses sodium nitrate as a halogen scavenger. Although removal of the halogen acid may be generally high, the propellant has several drawbacks including low burn rates R, a low specific impulse Isp and difficulties in processing. In addition, the range of burn rates is generally constricted to the narrow limits of about 0.32 to 0.42 inches per second.
New propellants have been devised for reducing or eliminating the halogen acids. Such propellants use a halogen free material in combination with ammonium nitrate as the oxidizer, but the burn rates, specific impulse and strain capability are unacceptably low. In addition, the propellant cost is prohibitive.
The need remains for an inexpensive, readily prepared and high performing propellant system in which halogenic acids do not appear in the exhaust gases or are scavenged from the exhaust plume shortly after discharge from the nozzle, either quantitatively or to a very low level.
SUMMARY OF THE INVENTION
This invention comprises a method for eliminating or greatly reducing halogenic acids such as hydrochloric acid from composite solid-grain rocket motor exhaust. In this invention, all elemental metal components of the propellant are eliminated except for one or more of magnesium, lithium, calcium or strontium. Thus, the magnesium, lithium, calcium and/or strontium is essentially the sole metallic component of the fuel and acts both as a primary fuel and as a halogen scavenger. The aluminum currently used in most solid rocket motors is preferably eliminated completely. It is desirable that metals other than Mg, Li, Ca and Sr are limited to less than about 3.0 percent of the propellant formulation.
Preferably, the metal is added to the propellant composition on an equivalence basis of about 2.5 to 4.0 equivalents metal per equivalent of halogen in the formulation. Thus, for a propellant formulation containing 70 percent ammonium perchlorate, the preferred concentration of magnesium, for example, is about 19 to 27 percent by weight of the formulation. More preferably, the metal is added at an equivalence basis of about 2.8 to 3.6.
While lithium, calcium and strontium may be used as complete substitutes for aluminum, they have mechanical and ballistic properties, and/or cost which make them unattractive. The preferred metal for use in this invention is magnesium, which has been found to provide good mechanical and ballistic properties, high acid removal, processing ease, safety and relatively low cost.
Propellants currently used in such programs as the space shuttle solid rocket booster use aluminum as the metallic fuel component and ammonium perchlorate (AP) as the oxidizer. The AP content of the propellant is typically about 60 to 70 percent. Thus, the chloride in the oxidizer ammonium perchlorate comprises about 18 to 21 percent of the total propellant weight. Upon combustion, it appears largely in the exhaust as hydrochloric acid. In space shuttle flights, the free hydrochloric acid content of the plume is known to comprise about 21 percent of the combustion products. The substitution of magnesium for aluminum in the formulation results in an exhaust cloud from which the chloride ion is essentially quantitatively scavenged by the metal to produce the benign solid metallic chloride, i.e. magnesium chloride MgCl 2 . Differing scavenging reactions take place both within the rocket combustion chamber and in the exhaust plume itself. The major reactions which remove the acid are dependent upon the presence of condensed water in the plume. The water present in the plume is a combustion product arising principally from hydrogen liberated from the organic binder materials.
Use of magnesium as a fuel/scavenger in the ammonium perchlorate based propellants has been found to enable the burn rate to be tailored over a wide range with the use of small quantities of iron oxide, e.g. ferric oxide.
Propellants which utilize magnesium as the sole metallic component have been found to be very similar to current space shuttle booster motor propellant in processability and mechanical properties.
DESCRIPTION OF THE DRAWINGS
In the drawings of the figures:
FIG. 1 is a schematic view of a solid rocket motor showing the chemical reactions taking place within the combustion chamber and in the external plume in accordance with the invention;
FIG. 2 is a graph of the results of tests showing the effect of magnesium content and aluminum content upon the removal of hydrochloric acid from rocket motor exhaust;
FIG. 3 is a graphical representation of the effect of iron oxide upon the burn rate of the propellant of the invention; and
FIG. 4 is a graphical comparison of the time degradation of HCl content in the exhaust plumes from a magnesium based propellant of the invention and the current space shuttle booster propellant.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The two stage chemical mechanism for hydrochloric acid scavenging from a rocket motor exhaust is depicted in FIG. 1. Solid propellant rocket motor 10 includes a casing 12 containing a solid propellant grain 14 and an integral combustion chamber 18. Nozzle 16 is attached to the casing 12 for the ejection of combustion products to form plume 22.
Many chemical reactions take place in the combustion chamber 18. The combustion products include magnesium oxide, carbon dioxide, hydrochloric acid, nitrogen, nitrogen oxides, water vapor and various ionic species. The reactions relating particularly to the formation of hydrochloric acid and to the scavenging of the acid by means of the invention, are as follows:
Combustion within the chamber 18 includes simplified reaction 20 by which magnesium Mg and ammonium perchlorate AP form magnesium oxide MgO, hydrochloric acid HCl, a relatively small quantity of magnesium chloride MgCl 2 , and other products not shown. Thus, a small amount of internal scavenging by magnesium occurs at the high combustion temperatures and pressures, typically up to about 1000 psi at 2000 to 6000 degrees F.
Combustion products 28 discharged from the rocket 10 include not only the species listed but hydrogen H 2 as well. The latter is a combustion product primarily of the organic polymeric binder material and is believed to be a prerequisite for complete conversion of the halogen acid to innocuous magnesium chloride in the plume 22.
Commonly used, halide-free propellant binders which are useful in the invention include hydroxyl-terminated polybutadiene (HTPB), polybutadiene acrylonitrile acrylic acid terpolymer (PBAN) and carboxy-terminated polybutadiene (CTPB). These binder materials may be used separately or in combination.
In plume 22, cooling and condensation of the combustion products occurs. As theorized in reaction 24, hydrogen H 2 is oxidized to water. Magnesium oxide reacts with the condensed water to form magnesium hydroxide Mg(OH) 2 which further reacts with the halogen acid in reaction 26 to form magnesium chloride. As shown in the examples infra, the hydrochloric acid may be removed quantitatively or nearly so by the use of magnesium as the sole metal in an AP based propellant.
Preferably, the magnesium is combined in the propellant batch as a particulate material in which the major weight portion has particle sizes in the range of between about 90 microns and 1.0 millimeter.
In a preferred form of the invention, the ammonium perchlorate particle size distribution is bimodal. The majority of the oxidizer has particle sizes in the 15-100 micron range and in the 150-400 micron range. Preferably, at least 80 weight percent of the particles fall into those size ranges.
More particularly, the bimodal peak concentrations fall within the 15-45 micron range and 150-250 micron range.
For the purposes of the invention, ammonium perchlorate represents any halogen-containing propellant component, and magnesium represents any of the metals magnesium, calcium, lithium, and strontium. Magnesium is the preferred metal, but any of these metals or combinations thereof may be used.
The requirements for a practical acid-scavenging rocket propellant not only include effective acid removal and the satisfactory ballistic performance factors, but also ease of production, safety, tailorability of burn rate, low cost, and other considerations. The propellant of the invention is shown in the following examples to excel in each of these areas.
EXAMPLE 1
The incorporation of metallic magnesium as a halide acid scavenging agent in an ammonium perchlorate (AP) based propellant was evaluated in small scale tests. The aluminum fuel was partially or wholly replaced by magnesium. Comparisons were made with the state-of-the-art, low-acid propellant which uses sodium nitrate as an acid scavenger. In all tests, the propellant included 12 percent total of an HTPB/IPDI binder and bonding agent. Small, i.e. one-gallon, batches of propellant were made according to the formulations A through F of the table below. One to five gram samples of the cured propellants were combusted in a closed combustion bomb containing 250 ml water. The combustion products entrained in the water were analyzed for chloride ion and free HCl. The specific impulse Isp, burn rate R, and burn rate pressure exponent n were also determined or calculated for each propellant sample. The test results were as indicated in the following table, columns A through F. Column G indicates the composition and typical burning characteristics of the currently used space shuttle booster solid propellant. A propellant formulation of the invention could be used to replace the current space shuttle formulation of column G in order to eliminate the hydrochloric acid in the exhaust plume.
______________________________________Propellant A B C D E F G______________________________________% AP 38.65 65.5 38.4 62.5 67.0 19.5 69.75% Al 21.0 0.0 18.0 15.0 10.0 18.0 16.0% Mg 0.0 22.0 3.0 10.0 11.0 3.0 0.0% NaNO.sub.3 28.1 0.0 28.1 0.0 0.0 25.0 0.0% AN 0.0 0.0 0.0 0.0 0.0 25.0 0.0% Fe.sub.2 O.sub.3 0.25 0.5 0.5 0.5 0.0 0.5 0.2Equiv. Mg/ 0.00 3.25 0.76 1.54 1.58 1.50 0.00Equiv. ClIsp, seconds 259.9 274.3 258.9 275.7 274.9 269.9 278.4Density, 0.068 0.061 0.067 0.064 0.063 0.064 0.064lb./in..sup.3Burn rate, ips 0.350 0.574 0.365 0.474 0.424 0.278 0.43Pressure exponent, 0.42 0.43 0.38 0.35 0.46 0.47 0.35% chloride 11.08 18.92 10.79 17.69 18.90 8.01 21.00ions in exhaustproducts% acid (as HCl) 3.5 0.0 2.58 10.10 6.75 3.83 20.00in exhaustproducts% acid removed 69.3 100.0 76.7 44.5 65.3 53.5 <5______________________________________
Propellant A is a state-of-the-art low-acid formulation which uses sodium nitrate as a halogen scavenger. The resulting acid removal was low, i.e. less than 70 percent. In addition, the specific impulse Isp was low.
Propellant B is a propellant formulation, according to the present invention, in which all metallic aluminum is replaced with magnesium. No sodium nitrate was used. Quantitative acid removal was achieved, and a high specific impulse resulted. The burn rate was considerably higher than that of baseline propellant A.
In propellants C, D, E and F, aluminum was partially replaced with magnesium. The presence of aluminum hindered acid scavenging even when a large quantity of sodium nitrate was included (propellants C and F) and when AP was largely replaced by energetic material ammonium nitrate (propellant F).
The results are plotted in FIG. 2 and indicate that aluminum in the propellant hinders removal of HCl from the plume.
Comparison of propellant B with the current shuttle booster propellant G shows that the acid scavenging formulation B provides specific impulse which is slightly below that of propellant G. The burn rate R is higher, and the pressure exponent n is also higher in propellant B.
EXAMPLE 2
Propellants having the following compositions were prepared in five, one-gallon mixes:
______________________________________Component Weight Percent______________________________________Binder 15.0OxidizerAP (nominal 200 micron) 39.9AP (nominal 20 micron) 23.0Total 62.9Fuel 22.0MagnesiumCatalyst 0.05, 0.10 and 0.15Fe.sub.2 O.sub.3______________________________________
Center perforated 70-gram motors were cast, cured for seven days at 135° and fired. The results are plotted in FIG. 3 and show a good correlation between catalyst concentration and burn rate R at 1000 psi. Regression analysis yielded a straight line relationship of:
Rate R=0.37278+0.42000 (Fe.sub.2 O.sub.3)
with a statistical variance of 0.003. Thus, the burn rate is readily and accurately controllable over a wide range using ferric oxide.
The burn rate is affected by various factors, particularly by variations in the concentrations of constituents in the formulation. Thus, the ferric oxide concentration required to obtain a particular burn rate may vary from as little as 0.0001 percent to as much as about 1.0 percent by weight. For most useful formulations, about 0.001 to 1.0 percent ferric oxide will be found useful.
EXAMPLE 3
Propellant formulations of the following compositions were prepared and manufactured in 70 gram motors. The hydrochloric acid content of the exhaust was evaluated for each 70 gram motor and compared to space shuttle propellant.
______________________________________In- Space NaNO.sub.3gredient Shuttle Mg/6% Al #1 NaNO.sub.3 #2 Mg/No Al______________________________________AP 69.75 62.5 38.5 39.5 62.5NaNO.sub.3 -- -- 28.0 29.0 --Al 16.00 6.0 21.0 19.0 --Mg -- 16.0 -- -- 22.0Fe.sub.2 O.sub.3 0.25 0.5 0.5 0.5 0.5______________________________________
Each propellant was fired as a 70-gram center perforated motor at 1000±100 psi. The exhaust was captured in a plume sampling device 10 feet from the nozzle exit plane. The sampling device was placed in the stream of the motor plume to capture exhaust in polyethylene bags.
The captured exhaust samples were analyzed for HCl with increasing time after the firing. HCl-specific Drager tubes were inserted into the polyethylene bags for visually reading the acid value.
In FIG. 4, data points from all of the test firings are shown as well as comparative data from current shuttle booster propellant batches. In all tests, the halide content of the shuttle booster propellant, expressed as maximum potential HCl in the exhaust, was 21.0 percent.
The results in FIG. 4 illustrate the effectiveness of magnesium as a scavenger for hydrochloric acid. The HCl in the exhaust plume immediately after firing was significantly reduced and declined to a negligible value with increasing time.
The theoretical HCl content of the plume gas at zero time at the nozzle exit plane for the magnesium based propellant was determined from the NASA Lewis thermochemistry code to be 13.8 percent. This is much higher than the actual data collected just after zero time. This may be attributed to either or both of the following:
(a) The magnesium initially scavenges the HCl to a much greater degree than theoretically calculated and/or.
(b) Extremely rapid scavenging occurs in the first two minutes after the end of motor burn.
As shown previously (FIG. 2), the partial replacement of Mg metal with Al metal inhibits the acid scavenging. FIG. 4 illustrates that the HCl scavenging efficiency of the Mg metal is diminished with the addition of 6% Al relative to the composition with no Al.
There appears to be some scatter in the analyses. This scatter is attributable in part to varying atmospheric conditions and inherent variability in visually reading the acid concentration from the Drager tube.
It is evident that considerable acid scavenging of HCl from the combustion products occurs prior to exit from the nozzle. The scavenging rapidly continues in the plume, however, until the HCl content is neutralized to a negligible or zero value.
Reference herein to details of the particular embodiments is not intended to restrict the scope of the appended claims which themselves recite those features regarded as important to the invention. | Scavenging and neutralization of HCl from the exhaust plume of a solid grain rocket motor is achieved by including elemental magnesium as the sole metallic component. The magnesium acts both as a propellant fuel and as a scavenger of halogen acids derived form the halogenic oxidizer. Combustion of the high energy propellant produces an exhaust plume from which the halogen acids are scavenged. | 2 |
[0001] This application claims the benefit of U.S. provisional patent application Ser. No. 60/899,314, filed Feb. 2, 2007, the disclosure of which is incorporated in full herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to pressurized containers and to methods for pressurizing and filling them. In accordance with a first aspect of the invention, the containers are completed by the container manufacturer and shipped ready to be filled. In a preferred embodiment a propellant is introduced into the completed container by the manufacturer before the container is shipped to a filler to be filled with product. According to a second aspect of the invention the container is pressurized and filled in a way to ensure that the container is not excessively pressurized during filling and an adequate pressure is maintained in the container until all or substantially all of the product is depleted during use.
[0004] 2. Prior Art
[0005] Pressurized containers are used to dispense a variety of products, including paint, lubricants, cleaning products, food items, personal care products such as hair spray, and the like. Pressure for dispensing these products is provided by a propellant placed in the container. In some prior art systems the product and propellant are stored separately in the container, i.e., separated by a barrier, e.g. a piston or bag, commonly referred as a barrier pack system. In other systems the product and propellant are stored together under pressure in the container. Dispensing of the product occurs when a discharge valve or nozzle is opened, permitting the pressurized product to be forced out through the nozzle, usually as a spray, stream, or foam. As product is depleted from the container, the pressure exerted by the propellant decreases, especially evident when compressed gases are used as the propellant, and the propellant pressure may become diminished to the extent that all of the product cannot be dispensed from the container, or a desired characteristic, e.g., atomization, is not achieved.
[0006] In addition to the propellant component, many products, e.g., hair spray, require a carrier, e.g., alcohol, or combinations of alcohol with water or other volatile solvents that dry quickly upon discharge from the container. Other volatile solvents or propellants that can be used in these systems include volatile organic compounds (VOCs) such as propane, isobutane, dimethyl ether, and the like, but their use is limited due to environmental concerns. For instance, under some current regulations no more than 55% of the contents of the container can comprise a VOC. In an aerosol dispenser, as much as 25% of the VOC could be required for use as a propellant, leaving about 30% VOC in the product. The balance of the product would be the active ingredients and water, which does not dry as quickly as the VOC, resulting in a “wet” product when used.
[0007] Carbon dioxide (CO 2 ) is useful as an aerosol propellant, but its use has been limited due to the fact that it is normally placed in the container as a pressurized or compressed gas, and in conventional systems the drop-off in pressure is excessive as the product is depleted and the volume occupied by the propellant increases. For example, in a typical situation the starting pressure might be 90-125 psig and the finishing pressure only 20 or 30 psig.
[0008] Conventional barrier pack systems typically comprise a can made of aluminum, steel, plastic, or other suitable material, with a barrier in the can between the product and the propellant. The barrier normally comprises a piston reciprocable in the can, or a collapsible bag in which the product is contained. In accordance with conventional practice, barrier pack cans are shipped empty from the manufacturer to a location where the can is to be filled, either with a piston in place in the can or a bag attached to the valve or the dome closing the end of the can. The filler adds the product, crimps and seals the valve in place in the opening provided for that purpose in the domed top of the can, and then injects the propellant.
[0009] If the barrier pack is of the type having a piston, the filler normally introduces product, e.g., a gel, through the opening in the domed top and into the can above the piston. The aerosol valve is then fitted and sealed to the can, and a propellant such as, e.g., isobutane, a VOC, is introduced under a predetermined pressure into the can beneath the piston through a sealing plug in the bottom of the can. If a liquefied propellant is used, some of it vaporizes until an equilibrium pressure is reached. The pressurizing propellant forces the piston up, placing pressure on the product so that it is discharged through the valve when the valve is opened.
[0010] In barrier packs utilizing a bag wherein the bag is affixed to the valve body on the bottom side of the valve cup with an undercup gasser, the filler introduces a propellant around the valve and into the can outside the bag, crimps the can, and then introduces product into the bag through the valve. Alternatively, a second method utilizes a plastic bag that is pre-inserted into the can and that has a formed one-inch neck shaped to fit the curl of the can, which allows product to be filled before the valve is applied and sealed. Propellant is then added through the sealing plug in the bottom of the can. The propellant exerts pressure on the bag, forcing product out through the valve when the valve is opened.
[0011] In those conventional systems wherein the propellant is mixed in the container with the product, the can manufacturer ships an empty container to the filler, who then places a desired quantity of product into the container, attaches and seals the valve, and then injects propellant through the valve to pressurize the product.
[0012] Prior systems have attempted to alleviate this problem by shaking the container in order to promote dissolution of the propellant into the product as the propellant is being introduced, thereby reducing the pressure spike or over-pressurization that occurs when the propellant is first charged into the container and thus avoiding deformation of the can. However, these prior art systems have not been entirely satisfactory because of slower gassing and the shaking required.
[0013] Various other systems have been developed in the prior art for storing a reserve supply of propellant and adding it to the container as product is depleted, so that propellant pressure is maintained at a desirable level until a suitable amount of the product is dispensed from the container. Examples of such systems are described in applicant's prior issued U.S. Pat. Nos. 6,708,844 and 7,185,786, and applicant's prior copending U.S. application Ser. No. 11/250,235, filed Oct. 14, 2005, all of which are incorporated in full herein by reference.
[0014] Common to the foregoing systems is the need for the filler to provide machinery for completing manufacture and/or assembly of the final product, and in the case of pressurized aerosol dispensers to inventory propellants and solvents in addition to the product. For many small fillers, in particular, this is a burdensome requirement due to the cost of the necessary machinery to complete manufacture of the containers and to store propellant gases, and when applicable the cost of carrying insurance and maintaining appropriate storage facilities for required propellants and solvents.
[0015] It would be advantageous to have an economical, efficient, and environmentally safe system and method for filling and pressurizing containers, wherein completed containers are shipped by the container manufacturer to the filler so that the filler does not require the necessary equipment to complete the vacuum crimping, propellant gas injection, gas storage tanks, and pumping equipment to complete the manufacture of the pressurized product, and does not need to incur the cost of carrying insurance and maintaining manufacturing and appropriate storage facilities for required propellants. Moreover, it would be advantageous to have a system and method for filling and pressurizing containers wherein the initial starting pressure is not excessive and satisfactory pressure is maintained throughout the useful life of the container.
SUMMARY OF THE INVENTION
[0016] According to a first aspect of the invention, a system and method is provided wherein the container manufacturer completes manufacture of a container before shipping it to the filler by attaching the valve and sealing the can so that the filler does not have to purchase the machinery necessary to complete manufacture of the containers. Preferably, and especially for pressurized aerosol dispensers, the manufacturer pre-charges the completed container with a desired quantity of propellant prior to shipping it to the filler, whereby the filler does not need to incur the cost of carrying insurance and maintaining appropriate storage facilities for the various propellants and solvents, requiring only product injectors.
[0017] According to a second aspect of the invention, a system and method is provided for filling and pressurizing containers, wherein a propellant is first charged into the container and product is then introduced in a way to ensure that the initial starting pressure is not too great and satisfactory pressure is maintained until substantially all product has been dispensed. This aspect of the invention could be practiced independently of the first aspect, i.e., the can manufacturer could ship a can empty to the filler, who would then introduce both the propellant and the product into the container, or in conjunction with it.
[0018] In this second aspect, the pressure of the compressed gas propellant pre-charged into the container typically is from about 40 psig to about 150 psig, and the line pressure of the product in the filling machine typically is in the range of about 600 psig. The desired quantity of product is charged into the container very quickly, typically over a time interval of only about 0.5 to 1.0 second. However, the restriction imposed by the container valve through which the product is introduced substantially reduces the pressure of the product from its line pressure, and some of the gaseous propellant is dissolved into the product as it is being violently introduced into the container, whereby the initial pressure in the container does not exceed about 160 psig as it is being filled. This pressure is well within acceptable limits. Applicant has determined that by filling and pressurizing the container in this way, enough propellant gas is in the container to obtain a satisfactory discharge pressure until substantially all the product has been dispensed, and the initial pressurization of the container during filling is kept within acceptable limits.
[0019] In a preferred embodiment, the product is chilled to a temperature of from about 34° F. to about 40° F. before it is introduced into the container. This promotes more rapid dissolution of compressed gaseous propellant into the product, helping to minimize or eliminate the pressure spike that might otherwise occur when the product is charged into the previously pressurized container.
[0020] In a further preferred embodiment, the product is introduced into the container in multiple steps, with only a portion of the product being introduced in each step. This also promotes dissolution of some of the propellant into the product, and provides more time for such dissolution to occur, further improving the ability of the invention to reduce or eliminate sharp increases in pressure in the container as it is being filled.
[0021] In another preferred embodiment, a predetermined quantity of dry ice (CO 2 in solid form) is placed in the container prior to the top of the container being applied and sealed as the container moves along the filling line. During the relatively short span of time between adding the dry ice and applying the top some of the CO 2 gases off, purging the container and thereby eliminating the need to purge the container in a separate step. The desired quantity of product is then injected into the container, and since most of the CO 2 is still in the form of dry ice the pressure in the container is relatively low. Thus, the increase in pressure caused in the container as the product is injected is minimal and well below an acceptable level. Thereafter, the CO 2 continues to gas off until an equilibrium pressure is reached, which typically is in the range of from about 90 psig to about 130 psig.
[0022] In yet another preferred embodiment, a material in which CO 2 readily and rapidly dissolves can be added to the product before the product is injected into the container. This will increase the speed with which CO 2 is dissolved in the product, helping to minimize any pressure spike that might occur when the product is injected into the container. Such materials may include acetone and comparable materials, depending upon their suitability for use in the product being packaged. Moreover, as part of their normal formulation many products contain a material in which CO 2 readily dissolves. Alcohol is an example.
[0023] In a still further preferred embodiment, a quantity of gas adsorption material is placed in the container to adsorb and store gaseous propellant. This material quickly adsorbs gaseous propellant when it is subsequently charged into the container, thereby substantially reducing the volume of propellant gas present in the container and thus minimizing the spike in pressure that would otherwise occur when the product is injected into the container. After the container is sealed and filled, the sorbed gas is slowly released from the sorbent material until equilibrium pressure is reached in the container, and continues to be released to maintain a desirable pressure as product is depleted from the container during use. The quick adsorption of the propellant gas into the sorbent material during pressurization, and its subsequent slow release until equilibrium pressure is reached avoids distortion of the can during pressurization. A preferred sorbent material is zeolite, and a preferred propellant gas is carbon dioxide, but other sorbents and/or gases may be used, as more fully described in applicant's copending application Ser. No. 11/250,235, filed Oct. 14, 2005, the disclosure of which is incorporated herein in its entirety by reference. As disclosed in that application, a preferred sorbent material is activated carbon, or a carbon fiber composite molecular sieve (CFCMS) as disclosed, for example, in U.S. Pat. Nos. 5,912,424 and 6,030,698, the disclosures of which are incorporated in full herein. Other materials, such as natural or synthetic zeolite, starch-based polymers, alumina—preferably activated alumina, silica gel, and sodium bicarbonate, or mixtures thereof, may be used to adsorb and store a quantity of a desired gas, although they generally are not as effective as activated carbon. Zeolite is particularly effective at adsorbing and desorbing CO 2 , especially if calcium hydroxide is added to the zeolite during its manufacture. Other base materials, such as potassium or sodium hydroxide, or lithium hydroxide or sodium carbonate, for example, could be used in lieu of calcium hydroxide.
[0024] The sorbent material may be in the form of a cohesive body, such as a ball, tube, cube or rod, or sheet or screen which may be flat or curved or folded into various shapes, such as, for example, an accordion-like fold. Alternatively, the sorbent material may be granular or powdered and enclosed in a membrane or pouch that is porous to the gaseous propellant and/or to the product in the container.
[0025] All or any number of the above approaches could be combined in a single process to obtain the combined benefits of each.
[0026] In accordance with a specific process for manufacturing, filling and pressurizing aerosol dispensers according to the second aspect of the invention, the discharge valve is crimped and sealed on a can, preferably by the can manufacturer in accordance with the first aspect of the invention, but the second aspect is applicable whether this is done by the can manufacturer or by the filler. A vacuum is then applied to the can to evacuate it. A measured amount of propellant, and in some cases solvent, is then charged into the container using suitable conventional equipment, either by equilibrium pressure (balance between pressure in the container and pressure in the gas supply line, typically about 125 psig) or a metering piston (gas cylinder injector) that injects a measured quantity of gas. A measured quantity of product, chilled to from about 34° F. to about 40° F., is then injected into the container with a metering piston.
[0027] Suitable propellants and/or solvents may include, but are not necessarily limited to: carbon dioxide; nitrogen; acetone; alcohol; argon (a preservative); propane; n-butane; isobutane (2-methylpropane); dimethyl ether; HFC-152a (1,1-difluoroethane); HFC-134a (1,2,2,2-tetrafluoroethane); nitrous oxide; ethyl fluoride (CH 3 —CH 2 F); fluoro-ethers (e.g., CHF 2 —O—CH 3 ); and compressed air; or combinations of these.
[0028] It should be understood that the size of the container, the formulation and quantity of the product, and the initial starting pressure of the propellant in the container can vary within the scope of the invention. Also, the amounts or proportions of the propellants can be varied to suit particular needs.
[0029] It is contemplated that by practicing the invention the amount of VOCs in various products could gradually be reduced over a period of time. That is, ever increasing amounts of an inert and/or environmentally friendly propellant and/or solvent could gradually be substituted for the VOCs in succeeding generations of containers.
[0030] It should be understood that the invention is applicable to cans made of aluminum, steel, or other material and is not limited to cans made of any particular material, and applies to cans made of one piece, two pieces, three pieces, or other constructions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The foregoing, as well as other objects and advantages of the invention, will become apparent from the following detailed description when considered in conjunction with the accompanying drawings, wherein like reference characters designate like parts throughout the several views, and wherein:
[0032] FIG. 1A is a longitudinal sectional view of a can shell for a pressurized dispenser, wherein the can shell and bottom are made in one piece, typically of aluminum.
[0033] FIG. 1B is a longitudinal sectional view of a can produced by applying a domed end to the open end of the shell of FIG. 1A .
[0034] FIGS. 2A , 2 B and 2 C are longitudinal sectional views of the can of FIG. 1B , showing the different stages performed by a filler in completing the product, including attaching the valve to the can, filling the can it with product, and pressurizing it according to conventional practice.
[0035] FIG. 3 is a longitudinal sectional view of a can for a pressurized dispenser as manufactured in accordance with the invention, wherein manufacture of the can is completed and propellant is charged into the can prior to shipment to a filler.
[0036] FIG. 4 depicts the step of filling the container of FIG. 3 with product, as performed by the filler.
[0037] FIG. 5 is a longitudinal sectional view of a pressurized dispensing container.
[0038] FIG. 6 is a somewhat schematic longitudinal sectional view showing a sealed container with a discharge valve and dip tube applied to the domed end.
[0039] FIG. 7 is a view similar to FIG. 6 , showing a vacuum being drawn on the container to remove air.
[0040] FIG. 8 is a view similar to FIG. 6 , showing a propellant gas being charged into the container through the valve assembly at the top.
[0041] FIG. 9 is a view similar to FIG. 6 , showing product being introduced into the container in a single step and depicting how the product swirls around the interior of the container as it is introduced.
[0042] FIGS. 10 and 11 are views showing the product being introduced into the container in two steps, with approximately half the product being introduced in FIG. 10 , and the balance being introduced in FIG. 11 .
[0043] FIGS. 12 , 13 and 14 are views showing the product being introduced into the container in three steps, with approximately one-third the product being introduced in FIG. 12 , one-third being introduced in FIG. 13 , and the balance being introduced in FIG. 14 .
[0044] FIG. 15 shows a container prior to the valve being applied to the opening through the domed top, and depicting a quantity of dry ice being placed in the container through the opening.
[0045] FIG. 16 shows the container of FIG. 15 after the valve has been applied.
[0046] FIG. 17 shows a subsequent stage during which product is injected into the container.
[0047] FIG. 18 shows the completed and filled container.
[0048] FIG. 19 is a view similar to FIG. 15 , but showing a quantity of sorbent material being placed in the container before the valve is applied and the container sealed.
[0049] FIG. 20 shows the gaseous propellant being charged into the container of FIG. 19 after the valve has been attached and sealed to the container body and a vacuum has been applied to remove air.
[0050] FIG. 21 depicts the step of injecting product into the container.
[0051] FIG. 22 shows the sealed and filled container, with the sorbent material disposed in the product.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0052] A can shell from which a typical pressurized aerosol dispenser is made is indicated generally at 10 in FIG. 1A . In the particular example shown, the shell comprises a one-piece body normally made of aluminum, and has a cylindrical side wall 11 with an open top 12 and an integrally formed bottom 13 . As shown in FIG. 1B , a domed top 14 with an opening 14 ′ through its center is crimped and sealed to the open top 12 to form a can. The can shown in FIG. 1B is what the manufacturer produces and ships to a filler, who fills the can with product, attaches and seals the valve in the opening 14 ′, and pressurizes the can with propellant, as depicted in FIGS. 2A-2C . In FIG. 2A the discharge valve assembly 15 and dip tube 16 are being assembled to the top 14 to produce a completed aerosol can with top and discharge valve, as indicated generally at 17 in FIG. 2B . The filler then performs the steps shown in FIGS. 2B and 2C . FIG. 2B depicts the product P 1 being added by injecting it through the valve 15 , and in FIG. 2C the propellant P 2 is being added.
[0053] In accordance with the first aspect of the invention, as illustrated in FIGS. 3 and 4 , the can manufacturer completes assembly of the can 17 by crimping and sealing the valve assembly 15 in place, and also adding propellant P 2 , all as shown in FIG. 3 . The completed can 17 , pre-charged with propellant, is then shipped to the filler where it is necessary only to add product, as depicted in FIG. 4 . The product may be added in accordance with the second aspect of the invention, as described more fully hereinafter and as illustrated in FIGS. 5-22 .
[0054] A typical aerosol dispenser is indicated generally at 30 in FIG. 5 . The dispenser includes a container 31 made of metal or other suitable material, having a bottom 32 and a top 33 . A discharge valve assembly 15 is mounted on the top and includes a nozzle 34 that may be manually depressed to open and permit product P to be dispensed from the container through the nozzle. A dip tube 16 extends from the bottom of the container to the discharge nozzle assembly. As seen in FIG. 5 , the level of product in the container does not occupy the entire volume of the container, and the space above the product level is filled with a pressurized propellant gas to exert pressure on the product and force it through the dip tube and nozzle when the nozzle is depressed. The foregoing structure and operation are conventional, and further detailed description of these basic components and their operation is not believed necessary.
[0055] In accordance with the second aspect of the invention, the valve assembly 15 and dip tube 16 are applied and the container 31 is sealed, as depicted in FIG. 6 . Air is then evacuated from the container by applying a vacuum to it, as shown at 35 in FIG. 7 . A predetermined quantity of gaseous propellant P 2 is then charged into the container as indicated in FIG. 8 . The propellant may be introduced using conventional equipment, such as by pressure equilibrium, wherein the gas is charged into the container until the pressure in the container equals the pressure in the gas supply line 36 , typically about 125 psig, or by injecting a metered quantity of the propellant using a metering piston or gas cylinder injector (not shown).
[0056] A metered quantity of product P 1 is then introduced into the container using conventional equipment such as, for example, a piston injector (not shown). As depicted in FIG. 9 , the product may be injected in a single step. The pressure in the product supply line 37 typically is in the range of about 600 psig and it takes only about 0.5 to 1.0 second to inject the desired quantity into the container, whereby the product is relatively violently introduced into the container. The pressure of the product entering the container is substantially less than the line pressure, but immediately upon the product being introduced into the container, some spike or transitory increase in pressure might be expected, although this transitory increase is only about 160 psig and is well below acceptable limits. Whether this occurs, the pressure is sufficient to induce considerable swirling and agitation of the product, as illustrated by the arrows “A”. This movement of the product as it is being introduced into the container results in thorough mixing and intermingling of the product and propellant, enhancing the speed with which some of the gaseous propellant is dissolved in the liquid product. The propellant not dissolved in the product quickly moves to the top of the container, filling the head space between the product level “L” and the domed container top, applying a pressure of about 125 psig on the product. In this regard, it should be understood that the initial or starting pressure in the container may have other values, depending upon the desired result.
[0057] FIGS. 10 and 11 depict an alternate filling method, wherein the product is injected into the container in two steps, each step involving a smaller quantity of product than is injected in the single step approach of FIG. 9 . Thus, as shown in FIG. 10 , a first quantity of product P 1 - 1 equal to approximately one half of the final desired amount of product to be placed in the container is introduced in a first step, and as shown in FIG. 11 a second quantity P 1 - 2 , or the balance of the desired amount to fill the container, is introduced in a second step. This approach reduces any transitory pressure spike caused by injection of the product into the container since less product is being introduced and the product takes up a commensurately smaller volume at each injection stage. The delay between the first and second stages, although very small, provides more time for propellant gas to be dissolved in the product.
[0058] FIGS. 12 , 13 and 14 depict a further method, wherein the product is injected into the container in three steps or stages. Thus, as shown in FIG. 15 , a first quantity of product P 1 - 1 ′ equal to about one-third the final amount of product desired in the container is injected in a first step, and second and third quantities P 1 - 2 ′ and P 1 - 3 are injected in respective succeeding steps.
[0059] In an alternative method as depicted in FIGS. 15-18 , a quantity of dry ice 40 is placed in the container through the opening 14 ′ before the valve assembly 15 is attached and sealed. As the container moves to the next station in the filling line, the dry ice begins vaporizing and the CO 2 given off floods the interior of the container, purging it. The valve assembly 15 is then attached and sealed to the body as depicted in FIG. 16 . This is followed by injection of product P 1 , as previously described, and as shown in FIG. 17 . The dry ice continues to vaporize until a starting equilibrium pressure is reached in the container, typically from about 90 psig to about 130 psig. The magnitude of this starting equilibrium pressure can be varied as desired, and depends to a primary extent on the quantity of dry ice placed in the container. At this point some of the dry ice may still remain, as shown in FIG. 22 , providing a small reserve supply of CO 2 .
[0060] A material in which CO 2 readily and rapidly dissolves can be added to the product before the product is injected into the container in any of the previously described forms of the invention. This will increase the speed with which CO 2 is dissolved in the product, helping to minimize any pressure spike that might occur when the product is injected into the container. Such materials may include acetone and comparable materials, depending upon their suitability for use in the product being packaged. Moreover, as part of their normal formulation many products contain a material in which CO 2 readily dissolves. Alcohol is an example.
[0061] To further enhance rapid dissolving of propellant gas in the liquid product, the product preferably is chilled to a temperature of from about 34° F. to about 40° F. before it is introduced into the container.
[0062] FIGS. 19-22 depict another alternate embodiment, wherein a predetermined quantity of adsorbent material 50 is placed in the container 31 through the opening 14 ′ before the valve 15 is attached. The adsorbent material preferably comprises natural or synthetic zeolite, and may be in the form of a cohesive body, or granulated or powdered and confined in a pouch or membrane that permits fluid contact between the product and the sorbent. FIG. 20 depicts the container after it has been closed and sealed, and shows the gaseous propellant P 2 being charged under pressure into the container from supply line 36 . A substantial portion of the gaseous propellant is quickly adsorbed into the sorbent material, reducing the volume of gaseous propellant free in the container. A predetermined quantity of product P 1 is then injected into the container from supply line 37 . If the pressure in the container is not at the designed equilibrium pressure after it is filled with the desired quantity of product, some of the gaseous propellant is desorbed from the sorbent material until the equilibrium pressure is reached.
[0063] All or any number of the above approaches could be combined in a single process to obtain the combined benefits of each.
[0064] Pressurized dispensing containers filled in accordance with the invention have adequate pressure throughout their useful life (typically about 50 psig remaining when the container is empty of product) without requiring excess propellant to be initially charged into the container, and without incurring an unacceptable pressure spike during filling. The invention may be practiced with conventional equipment.
[0065] While particular embodiments of the invention have been illustrated and described in detail herein, it should be understood that various changes and modifications may be made to without departing from the spirit and intent of the invention. | According to a first aspect of the invention a can manufacturer completes manufacture of a can and then ships it to a filler, who needs only to fill the can with product. In a preferred embodiment the manufacturer pre-charges the container with a propellant. In accordance with a second aspect of the invention a desired quantity of gaseous propellant is first charged into a container, and a desired quantity of product is then injected into the container. A container filled in accordance with the invention maintains a predetermined pressure in the container as product is depleted from the container, and unacceptable pressure spikes are avoided as the container is being filled. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser. No. 13/015,722, filed Jan. 28, 2011 and now issued as U.S. Pat. No. ______, which is a continuation of U.S. application Ser. No. 11/601,957, filed Nov. 20, 2006 and now issued as U.S. Pat. No. 7,904,939, which is a continuation of U.S. application Ser. No. 09/752,267, filed Dec. 29, 2000 and issued as U.S. Pat. No. 7,140,033, with all applications incorporated herein by reference in their entireties. This application also claims the benefit of U.S. Provisional Patent Application No. 60/213,058, filed Jun. 21, 2000, and incorporated herein by reference in its entirety. This application also claims the benefit of U.S. Provisional Patent Application No. 60/214,529, filed Jun. 27, 2000, and incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] This invention deals with methods and systems for delivering and executing at a Set Top Box (“STB”) or other consumer electronic device, control or program data, whereby the STB interfaces with various external devices for sending or receiving instructions or information to those devices. Exemplary embodiments are illustrated, including methods and systems for supplementing delivered programming with Internet programming via a PC or Internet appliance coupled to the STB, controlling environmental equipment such as home theatre equipment, and managing programming scheduling via interface with a personal digital assistant (“PDA”).
BACKGROUND OF INVENTION
[0003] Modern cable, satellite, wireless or other communications networks deliver a host of programming content and other data to viewers' premises, each of which generally is outfitted with a STB or Consumer Electronics device (“CE device”) for decoding and displaying the programming. STBs are usually low-cost devices and, due to engineering constrains, presently lack the necessary processor speed, memory and components to support Internet applications or advanced data gathering capabilities. However, many STBs do have the capability to communicate with an external device through one of several communication mechanisms, such as an IR blaster, serial port, modem, or expansion bus peripheral. These communication devices have not in the past been used for much more than entering typical scheduling and control data into the STB, however.
[0004] Scheduling has been made easier because part of the programming delivered to STBs are Electronic Program Guides (“EPGs”). These guides provide a viewer with program scheduling information, e.g. a program's channel or other characteristics of the program such as whether the program supports particular protocols like Dolby AC-3 sound, etc. EPGs also can be used to accomplish other useful tasks, such as instructing a STB to tune to a program based on user preferences or instructing a VCR to record a program. Indeed, some EPGs offer the ability to create reminders for program start times. These reminders usually appear as visual alerts on the television screen when the program is about to begin. However, if the user is not watching television at the time these alerts occur, they are of little value.
SUMMARY OF THE INVENTION
[0005] Certain terms used in this section are described more fully below, particularly in the “Terminology” session. This invention aims to provide systems and methods to leverage existing technologies located at a viewer's premises, e.g., the viewer's PC, existing PC Internet connection, STB, and existing EPG data delivery format, to deliver, receive and act upon information and instructions for certain external devices. Exemplary implementations are described where: (1) an STB is connected to a viewer's PC and an application, residing on the STB, retrieves data from the PC using special tags embedded in EPG program data or accesses a host of special Internet related applications while viewing other programming; (2) an STB makes use of information added to or already included in EPG program data to control aspects of the user's home theater environment during a TV program; (3) an STB communicates with an application on a Personal Digital Assistant (PDA) to set reminders about programming, for example, start times, etc. or download program information to the PDA for storage and display, etc.
[0006] Program Supplementation:
[0007] In one embodiment, control tags are inserted into the data stream that provides STBs with the EPG data. An application residing on the STB identifies the control tags, strips them out and processes the instructions therein. The instructions may cause the STB to communicate with a PC, Internet appliance or other computing device that has been coupled to the STB via any of various known communication mechanisms. The STB thereby can take advantage of the functionality, processing power and display capabilities of the computing device. Using this capability, an STB can supplement its limited capabilities by using the processing power of the PC and the information gathering ability of a PC connected to the Internet. By way of example, tags delivered to the STB may cause it to retrieve Internet data via the user's PC or Internet appliance. That Internet data can be used to supplement EPG data on the STB or display data synchronized to a currently playing event. Alternatively, retrieved Internet data may be stored on the PC for immediate or later viewing.
[0008] Environmental Control:
[0009] In another embodiment, the tags embedded in the EPG data stream (or the programming itself) comprise certain control data that correlate to a particular program or event. The control data describes how the user's home theater equipment (e.g., stereo, wall-screen TV, thumpers, scent extractors, etc.) should be optimally controlled during the program presentation. Control data can be used to do such things as configure home audio equipment to best accommodate a program's soundtrack, adjust TV picture settings, automate room lighting, mute commercials, or even “censor” portions of a TV program.
[0010] PDA Interfacing:
[0011] Many people now carry PDAs, which provide scheduling and task management capabilities. This invention also provides methods for allowing external devices like PDAs to interface with the STB in order to display alerts or other information concerning programming using the PDA unit's built-in calendar and alarm capabilities. Similarly, the PDA may be configured to send information to the STB application, for example, instructing it to set reminders for programs or to automatically record programs on a VCR, DVR or other storage medium.
[0012] This invention aims to achieve one, combinations, or all of the following objectives:
To formulate program control data associated with discrete portions of programming, which contain information related to controlling presentation of the programming by controlling the manner in which various home theatre or other display and audio devices should be controlled; To provide an STB that receives and processes control data and communicates instructions therefrom to external devices coupled to the STB; To formulate control data that describes when and how to access supplemental program data, such as data from an Internet Website, via a user's PC, Internet appliance or other computing device; To provide methods for coupling an STB to a user's PC, Internet appliance or other computing device in order to exchange information and instructions.
Other objects, advantages and features of this invention will be apparent from review of the remainder of this document, including the drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a diagram illustrating an embodiment of a system for controlling a home automated network using EPG tag information according to the present invention.
[0018] FIGS. 2A-C are diagrams illustrating methods of connecting the STB to the home automated network described in FIG. 1 .
[0019] FIG. 3 is a diagram illustrating an embodiment of a system for facilitating communications between a STB and a PDA according to the present invention.
[0020] FIGS. 4A-C are diagrams illustrating methods of connecting the STB to the PDA described in FIG. 3 .
[0021] FIG. 5 is a diagram illustrating a networked control system, including a PC, according to the present invention.
[0022] FIGS. 6A-E are diagrams illustrating methods for connecting the STB to the PC described in FIG. 5 .
DETAILED DESCRIPTION
I. Terminology
[0023] Before further describing a particular implementation of the present invention that is shown in the drawings, the following terms are explained, although more thorough understanding of the terms can be reached by resorting to this entire document. These term explanations are not intended to be conclusive, as technology will change and skilled persons will recognize other ways to implement the same functionality.
“Communications network” includes any network or infrastructure that supports communications between multiple devices, including broadband distribution networks, public or private packet-switched or other data networks, including the Internet, or circuit-switched networks such as the public switched telephone network and wireless networks. “Consumer electronics device” or “CE device” is any electronic device or combination of devices capable of receiving, displaying, playing, presenting, recording, deleting, editing, substituting, or disabling audio and/or video content. Exemplary CE devices include: televisions, personal computers, cable set-top boxes, video cassette recorders, digital video recorders, digital video disc players, compact disc players, and personal computers. “Content data” is any information corresponding to at least a portion of a program and related to the content of the program, including content ratings and content attributes, traits, or characteristics. “Control data” is any information corresponding to at least a portion of a program and related to the manner in which the portion may be disabled, modified, replaced, deleted, edited, or otherwise modified by a consumer electronics device, set top box or the like. “Program” or “Programming” is any electronic presentation of information, such as text, audio, video, graphics, or any other form of multimedia, over a communications network. Exemplary programming includes: Internet programming, television broadcasts, cable television programming, pay-per-view programming, video-on-demand, interactive television programming, satellite programming, and multimedia presentations. “Program data” means content or control data or other data associated with or describing the content or manner of presentation of programming. “Service provider” is any entity that delivers programs to a program viewer, including cable providers, television broadcasters, satellite providers, and entities supporting Internet World Wide Web (“Web”) sites.
II. System Overview
EPG Environmental Control
[0031] Briefly, FIGS. 1 , 3 and 5 show system components for delivering data that controls various devices that assist in the optimal presentation of programming. In the subscriber's premises, a Set-Top Box 3 connects through a distribution network 2 to a headend 1 . Set-Top Box 3 also connects to the subscriber's consumer electronic (CE) device 4 , for example a VCR, stereo, computer, etc. and/or home automation network 5 . The CE device 4 is in turn connected to the Internet through an Internet service provider. As skilled persons will acknowledge, instead of STB 3 , the invention could be implemented using software and hardware associated with a CE Device, such as a TV 8 .
[0032] A. STB—CE Device Connection
[0033] Set-Top Box 3 can be connected to CE device 4 and/or home automation network 5 through a variety of means. Some detailed examples are listed below. The hardware details of the STB-home theater connection are provided here for technical reference only and the invention is not limited to such details.
1) Using an IR blaster connected to the STB's IR blaster port, the STB may use IR signals to communicate with consumer electronic devices such as a stereo amplifier or a home automation network. ( FIG. 2A ) 2) Using the STB's serial port, the STB may connect to a peripheral that converts the RS-232 signals used by the STB into a standard signal used by CE devices and home automation networks. Such signals include signals in the IEEE 1394 (aka: Firewire) or CEBus ( FIG. 2B ) formats. 3) Using the STB's expansion bus, the STB could be connected to the peripheral described above, as shown in ( FIG. 2C ).
[0037] B. Data Tags
[0038] Headend 1 houses an EPG Data Server 6 that collects program data from a data provider. The program data includes information on each TV program such as the program title, start time, duration and description. EPG Data Server 6 sends the program data through distribution network 2 to Set-Top Box 3 located in the subscriber premises. Some of the applications listed in the next section may be accomplished by using information already contained within the EPG data, such as a program's start time and Dolby AC-3 indicator. However, specific control by the EPG must be carried out using special data referred to as “tags,” which according to this invention are added to EPG program data to provide more detailed information on controlling the user's home theater environment. The tags instruct the STB application to send control information to specific CE devices and/or home automation networks during the course of a program. For instance, a tag may instruct the STB to configure a stereo amplifier, adjust the TV picture, and dim the lights at the start of a program. A tag may also indicate times at which commercials or possibly objectionable content occurred during a program and send instruction to a TV to mute or blank those portions of the program.
[0039] The tags may be added to the EPG data by the EPG data provider or could be added by an optional device in headend 1 referred to as the “Home Control Tag Server” 7 . In this latter case, the EPG Data Server 6 sends the EPG data to the Home Control Tag Server 7 , which in turn inserts special data referred to as “tags” into the program data for particular TV programs.
[0040] Tags may be classified as fixed or variable tags; “Fixed Tags” specify a parameter for the entire length of a program while “Variable Tags” vary a parameter at different times during a program. An example of a variable tag would be one that mutes TV commercials.
[0041] The tag would be encoded as a special ASCII string and could include the following elements:
1) Command. A command may be an instruction that an applet on the STB send control instructions to specific CE devices and/or a home automation network. For instance, the command could be “Switch Tuner to Dolby Surround Sound.” 2) Parameters. Each command could have one or more parameters associated with it. For instance, “raise Dolby sound to level 5.” 3) Start Offset and Duration. A command could have a start offset and duration associated with it to indicate when the command becomes active during the course of a program. (A negative start offset could be used to indicate that the command becomes active before a program begins.) More than one start offset and duration could be provided to make a command active during different portions of a program (e.g. mute commercials).
[0045] A detailed example of a possible tag format follows, although many different tag formats and instructions are possible:
[0000] <command [param1, param2,...] > -or- <OFFSET start1;duration1, [start2;duration2, start3;duration3 ...] > <command [param1, param2,...] > </OFFSET>
In this example,
“< >” indicates the beginning and end of a tag. “Command” indicates an instruction to the STB application. “Param” indicates a parameter associated with the command. “OFFSET” and “/OFFSET” is used to indicate that the enclosed command(s) begin at some offset from the beginning of the program. “Start” is the starting offset from the beginning of the program. “Duration” is the length of time the command is valid from the specified “Start” offset. If Duration is not specified, the command remains in effect until the end of the program or until some other event occurs.
[0052] Here are some examples of how this tag format could be used to instruct the STB to configure home audio equipment and lighting for a Pay-Per-View event:
PPV Command: <LT1 50%> <ST_VOL 20%> <ST_EQU 80 , 50 , 60 , 65 , 70 > <ST_SUR AC3>
In the PPV Command:
[0000]
“LT1”, “ST_VOL”, “ST_EQU”, and “ST_SUR” are instructions to set room lighting, stereo volume, stereo equalization, and stereo surround sound, respectively when the program begins.
“50%”, “20%”, “80,50,60,60,70”, and “AC3” are parameters used by each of the above instructions.
Block Command: <OFFSET 00:05:13; 5, 00:19:32; 20> <BLOCK-MUTE PG-13> </OFFSET>
In the Block Command:
[0000]
“BLOCK-MUTE” is a command to mute objectionable portions of a program if the user has the option activated.
“PG-13” is the rating level the user's STB setting would have to match or exceed in order for the muting to take place.
“00:05:13; 5, 00:19:32; 20” are two different start offset and duration pairs, meaning that the command will be active at two different times during the program.
[0060] Tags may be inserted into a variety of places in the program data. A new data field could be created to accommodate the tags or the tags could be added to an existing EPG data field such as the program description. The latter option is optimal since it can use existing EPG data formats such as DVB-SI.
[0061] For instance, the tag could be encoded as an ASCII text string and added to the end of a program's description. The STB application would recognize the tag and act on its instructions. However, the STB application would not display the actual tag string to the subscriber when the subscriber displays the program description.
[0062] C. System Capabilities
[0063] Using the system described above, a number of control capabilities may be programmed into the EPG data allowing a broadcast provider to offer new and enhanced programming and supplemental products. In addition, users are able to optimize and enhance their television programming. For example, the user could have the ability to adjust, enable or disable any aspect of any application listed below. For instance, the user could disable automatic stereo control for all programs or make it active only for purchased IPPV programs. The following is a listing of some of the enhanced capabilities of the present invention:
Stereo Amplifier Control. The STB application may use existing EPG data or special tags embedded in the program data to adjust a stereo amplifier. For instance, existing EPG data such as a program's AC-3 indicator could be used by the STB application to put the stereo into AC-3 mode during a program. Special tags could be added to program data to do such things as adjust the stereo volume, stereo equalizer, or speaker levels. At the end of the program, stereo settings could be restored to their original or default settings. TV Control. The STB application could use tags embedded in the program data to adjust different aspects of a television set. For instance, tags could adjust picture or sound settings to best accommodate a particular program. At the end of the program, picture or sound settings could be restored to their original or default settings. Lighting Control. The STB application could use existing EPG data such as a program's start and end times or special tags embedded in the program data to control room lighting. For instance, room lights could be set to automatically dim at the start of a purchased IPPV program and then brighten at the end of the program. Also, special tags could instruct the STB application to brighten room lights during TV commercials, allowing the user to find their way to the kitchen. Other Home Automation Control. The STB application could use existing EPG data such as a program's start and end times or special tags embedded in the program data to control other parts of a home automation network. For example, at the start of a program, the STB application could automatically mute a telephone ringer, adjust window shades, adjust room temperature, or activate a popcorn popper. Commercial Mute/Replace. The STB application could use tags embedded in the program data to mute volume, or tune to a special channel or video input during TV commercials. Dynamic Parental Controls. The STB application could use tags embedded in the program data to mute or blank portions of a program that exceed a certain parental control rating. On-Screen Graphics and PIP Display. The STB application could use tags embedded in the program data to enable or disable on-screen displays generated by the STB or some other consumer electronics device. Also, tags could be used to automatically enable, disable or configure a Picture-in-Picture (PIP) display. Motion Simulator. The STB application could use tags embedded in the program data to control a motion simulator or a feedback device such as a chair that vibrates. Aroma Generator. The STB application could use tags embedded in the program data to control an aroma generator. The aroma generator could generate aromas that correspond to the content of a program.
III. System Overview
PDA Reminder Exchange
[0073] FIG. 3 shows system components for connecting the STB to a PDA. In the subscriber's premises, a Set-Top Box 3 is connected through a distribution network 2 to a Headend or Transmission Facility 1 . Set-Top Box 3 is also connected to the subscriber's Personal Digital Assistant(PDA) 4 . An EPG Data Server 5 in the Headend or Transmission Facility 1 provides Set-Top Box 3 with program information on each TV program such as program title, start time, duration and description.
[0074] A. STB—PDA Connection
[0075] Set-Top Box 3 can be connected to a Personal Digital Assistant 4 through a variety of means. Some detailed examples are listed below. Note that the hardware details of the STB-PDA connection are not the main focus of this invention, which may be implemented over a number of platforms.
1) Using an IR blaster connected to the STB's IR blaster port, the STB could send IR signals to a PDA with a built-in IR receiver. Also, the PDA's built-in IR transmitter could be used to send IR signals to the existing IR receiver on the STB for two-way communications. ( FIG. 4A ) 2) Using the STB's serial port, the STB could be connected to a data communications port on the PDA. This means of communication would offer two-way data transmission. ( FIG. 4B ) 3) Using a peripheral connected to the STB's expansion bus (e.g. an Ethernet card), the STB could be connected to a data communications port on the PDA. This means of communication would offer two-way data transmission. ( FIG. 4C )
[0079] B. System Capabilities
[0080] A STB application such as an Electronic Program Guide (EPG) would be enhanced to send and receive information to and from a PDA using the system described above. In this embodiment, the following applications could be supported.
1) Set PDA Reminders. While watching television, the user sets reminders for current or future programming using the enhanced EPG application running on the STB. After program reminders are set, the user positions the PDA in front of the STB's IR blaster (or connects the PDA to the STB via some other hardware configuration, as shown in FIGS. 4A-C , and the enhanced EPG application communicates these reminders to a special application residing on the PDA. The special PDA application adds the program reminder as an entry in the PDA's built-in calendar application. It also configures the calendar application to notify the user with a visual and/or audible alarm before the start of the program. Of course, instead of using the PDA's built-in calendar application, the special PDA application may be designed to perform these functions on its own. 2) Display EPG Info from the STB on the PDA. The enhanced EPG application residing on the STB sends EPG program data to software residing on the PDA for storage and display. 3) Schedule EPG Reminders or Recordings. After EPG program data has been sent to the PDA, the user sets program reminders and/or schedules program recordings on software residing on the PDA. At some point later in time, the PDA transmits the settings to the enhanced EPG application residing on the STB, which in turn sets program reminders and schedules program recordings within the EPG application.
IV. System Overview
PC InterLink
[0084] Briefly, FIG. 5 shows a variety of system components for connecting and communicating between a STB and a PC. In the subscriber's premises, Set-Top Box 3 is connected through distribution network 2 to Headend or Transmission Facility 1 . Set-Top Box 3 is also connected to the subscriber's Personal Computer (PC) 4 . PC 4 is connected to the Internet through an Internet service provider. Of course, instead of STB 3 , the invention could be implemented using software and hardware associated with some other CE Device such as a TV, VCR, or DVD Player.
[0085] A. STB—PC Connection
[0086] Set-Top Box 3 can be connected to Personal Computer 4 , in FIG. 5 , through a variety of means. Some detailed examples are listed below.
1) Using the IR blaster port, the STB could communicate with a PC using one of the following two means. These means of communication offer only one-way data transmission at slow speeds.
(a) An IR blaster connected to the STB's IR blaster port could send IR signals to an IR receiver peripheral connected to a standard port on a PC. ( FIG. 6A ) (b) The STB's IR blaster port could send electrical signals directly to a peripheral connected to a standard port on a PC. The peripheral would translate the electrical signals sent out via the STB's IR blaster port into signals understood by one of the PC's standard ports. ( FIG. 6B )
2) Using the STB's serial port, the STB could be connected to the PC's serial port. This means of communication would offer two-way data transmission at moderate speeds. ( FIG. 6C ) 3) Using a peripheral connected to the STB's expansion bus (e.g. an Ethernet card), the STB could be connected to a standard port on a PC. This means of communication would offer two-way data transmission. ( FIG. 6D ) 4) Using the STB's modem phone port, the STB could communicate with a modem connected to the PC. This means of communication would offer two-way data transmission. ( FIG. 6E )
[0093] B. Data Tags
[0094] Referring to FIG. 5 , Headend or Transmission Facility 1 houses an EPG Data Server 6 that collects program data from a data provider. The program data includes information on each TV program such as the program title, start time, duration and description. The EPG Data Server sends the program data to an “Internet Tag Server” 7 that inserts special data referred to as “tags” into the program data for particular TV programs.
[0095] The tags act as instructions to a STB application to retrieve Internet data from a PC. Before retrieving this data, the tag could include instructions for presenting the subscriber with different data retrieval options. For instance, a tag in the program data for a baseball game could instruct the STB to display options on the TV screen called “Batter Statistics” and “Pitcher Statistics.” If the subscriber selects the “Batter Statistics” option, the tag instructs the STB to retrieve statistics on the current batter from a PC connected to the Internet and display them on the TV screen.
[0096] A tag may include the following elements:
1) Command. A tag would include a command such as “fetch Internet data from a PC” or “display a menu of data retrieval options to the subscriber.” Also, in addition to retrieving Internet data, commands could do other things such as “bookmark a web site on the subscriber's PC.” See the “System Capabilities” section below for further examples. 2) Command URL. A command could have a URL associated with it. The URL could be a normal Internet URL such as “www.bellsouth.com” or, to save memory, the URL could be represented in some shorthand notation, e.g. “wbls”, understood by the STB or PC applications. 3) Command Parameters. A tag command could have one or more parameters associated with it. For example, the command to display a menu of data retrieval options to the subscriber could have a parameter that indicates the format that the menu options are to be displayed in. Another parameter might indicate when the menu should be displayed. For instance, a menu could be displayed while the subscriber is watching the TV program or when the subscriber calls up EPG information on the program. 4) Menu Option Names. A tag could list the names of menu options to be displayed to the subscriber. 5) Menu Option Actions. A tag could include instructions on what to do if the subscriber selects a particular menu option. For instance, an action might be to retrieve and display a specific type of data from an Internet site. 6) Menu Option Parameters. A tag could include parameters for a menu option. For instance, a parameter could instruct the STB application on how to display results when a menu option is selected.
A detailed example of a possible tag format follows, although many different tag formats and instructions are possible.
[0000]
<command URL [param1, param2,...] >
[<menuoption1 action1 [param1, param2,...]>,
< menuoption2 action2 [param1, param2,...]>
...
</command>]
[0103] Here is an example of how the tag format could be used to present the subscriber with menu options and retrieve supplemental EPG data for the movie “The Matrix”. The following represents an embedded command for that movie:
[0000] <DISPMENU wbls/matrix descript,buttons1> <”Director Bio” DispData=director box1> <”Cast Notes” DispData=cast box1> </DISPMENU>
In this example,
“DISPMENU” is a command to display menu options for the program “wbls/matrix” is shorthand notation for a special web URL setup to provide data for the program. In this example, “wbls/matrix” is shorthand notation for the web URL “www.bellsouthmovies.com/matrix”. “descript,buttons1” are command parameters. In this example, “descript” indicates that the menu should be displayed when the subscriber calls up the program's description box, and “buttons1” indicates a standard format in which to display the menu options. “Director Bio” and “Cast Notes” are the names of the menu options to display to the subscriber. “DispData=director” and “DispData=cast” are the actions the STB application should take when the subscriber selects the menu options. In these cases, the STB application will retrieve data on the director or cast notes from the web URL “wbls/matrix” (“www.bellsouthmovies.com/matrix”). “box1” indicates the format in which to display the resulting data.
[0110] Tags can be inserted into a variety of places in the program data. A new data field could be created to accommodate the tags or the tags could be added to an existing EPG data field such as the program description. The latter option is optimal since it can use existing EPG data formats such as DVB-SI. For instance, the tag could be encoded as an ASCII text string and added to the end of a program's description. The STB application would recognize the tag and act on its instructions. However, the STB application would not display the actual tag string to the subscriber when the subscriber displays the program description.
[0111] C. System Capabilities
[0112] Using the system described above, the following capabilities could be supported:
1) Supplemental program information. Existing EPG data for a current or future event is supplemented by data retrieved from a PC attached to the Internet. The additional data can be displayed on the TV screen as part of the EPG data or displayed on the PC screen in a special window. Multiple options may be presented. For example, the STB application may display a menu giving the subscriber the ability to retrieve data on a show's cast or call up trivia on the particular episode. 2) Real-time data. Data is synchronized to a currently playing event. For instance, current pitcher and batter statistics could be provided during a baseball game. The STB application could present a menu in the bottom corner of the screen allowing the subscriber to display statistics on either the pitcher or batter. If the subscriber selects an option, the STB application requests the information from the PC. The PC, in turn, visits a special web site that provides data that is specially formatted and synchronized to a TV channel being viewed. The statistics on the current pitcher or batter are then displayed in a window (e.g., a picture in picture or PIP window) on the TV screen. 3) PC browsing. The STB application allows the subscriber to display related data on a current or future event on the subscriber's PC. The data could be displayed on the PC in several different ways. For instance, the data could be part of a web page that is automatically called up in a web browser such as Netscape. The data could also be stored on the PC for later viewing. 4) Automated bookmarks. Instead of going ahead and displaying a related web page on the PC, the STB application could instruct the PC to store a web page as a bookmark for later viewing. 5) Purchasing. The STB application allows the subscriber to purchase products related to a current or future event over the Internet. While the STB application would initiate the purchase, the complete purchase process could take place on the STB or the PC. 6) Calendar reminder. The STB application could instruct the PC to add the name and start time of an event to a calendar application on the PC. The calendar application would alert the subscriber to when an event begins. The calendar application could interface with a personal digital assistant such as a Palm Pilot, etc. by downloading information when the PDA is synchronized with the calendar function on the PC. 7) Printing. The STB application could send event information to a PC and instruct the PC to print the event information on a printer. 8) Screen capture. The STB application could send a screen capture to the PC for use in a variety of PC applications. 9) Bill review. The STB application could instruct the PC to retrieve the subscriber's billing information from the Internet for display on the TV or PC. 10) Interactive help. The STB application could instruct the PC to retrieve interactive help from the Internet for display on the TV or PC.
[0123] While this invention has been described in conjunction with specific embodiments, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the present invention that are here described are intended to be illustrative and not limiting. Various changes may be made without departing from the true spirit and full scope of the invention as defined in the following claims. | Methods, systems, and products control external devices during presentation of multimedia content. When a description of the multimedia content is received, the description includes control data for controlling an external device. The control data is stripped therefrom and sent to the external device to alter a presentation of the multimedia content | 7 |
TECHNICAL FIELD
[0001] The present invention relates to an improvement of a chemical/physical phenomenon detecting device.
BACKGROUND ART
[0002] As a chemical/physical phenomenon detecting device, a cumulative chemical/physical phenomenon detecting device disclosed in Patent Document 1 is known.
[0003] This detection device is used as, for example, a pH sensor, and removes the influence of remaining charges due to a potential barrier (so-called “bump” of potential). The remaining charges can be a factor of generating a false signal so that the charges should be removed to perform high-sensitivity detection.
[0004] In a prior chemical/physical phenomenon detection device, this potential barrier is formed at a position adjacent to the first charge control electrode which defines the potential of an Input Charge Control (ICG) region. That is, a silicon nitride film defining the sensing region on the substrate inherently covers the first charge control electrode according to the manufacturing process of the device, so that the silicon nitride film becomes thick on the side surface of the first charge control electrode. Hence, the external environment is not sufficiently reflected in the potential change of the substrate.
[0005] As a method for removing the influence of the remaining charges due to the potential barrier, a charge removal well is provided between the input charge control region and the sensing region. By controlling the potential of this removal well, the remaining charges in the sensing region is forcedly attracted to this removal well, thereby preventing the generation of the false signal.
PRIOR ART DOCUMENT
Patent Document
[0006] Patent Document 1: Japanese Patent No. 4171820
[0007] Patent Document 2: Published Japanese Translation No. 2010-525360
SUMMARY OF THE INVENTION
Problems to be Solved by the Present Invention
[0008] A second charge control electrode is disposed at a position corresponding to the removal well in addition to the first charge control electrode for controlling the potential of the removal well formed between the sensing region and the input charge control region.
[0009] On the other hand, techniques for two-dimensionally measuring changes in the external environment such as pH by integrating the chemical/physical phenomena detection devices are being developed, and in this development, a higher density of integration of the devices is required.
[0010] A chemical/physical phenomenon detection device disclosed in Patent Document 1 adopting a structure in which a second charge control electrode and a wiring for driving the second charge control electrode are added is not preferable from the viewpoint of high integration thereof.
[0011] Of course, it is needless to say that a higher sensitivity is required for a chemical/physical phenomenon detection device, so the influence of the false signal caused by the potential barrier must be eliminated.
[0012] In view of the above, it is an object of the present invention to provide a chemical/physical phenomenon detecting device suitable for high integration while eliminating a potential barrier.
Means to Solve the Problems
[0013] As a result of intensive studies to achieve such object, the present inventors have conceived the chemical/physical phenomenon detecting device of the first aspect. That is, A chemical/physical phenomenon detection device comprising;
[0014] a sensing region in which the potential of the sensing region changes in accordance with a change in an external environment,
[0015] a charge input region for supplying charges to the sensing region,
[0016] an input charge control region interposed between the sensing region and the charge input region, and
[0017] a charge accumulation region for accumulating charges transferred from the sensing region, wherein a diffusion layer is formed between the input charge control region and the sensing region on an substrate, and dopants for generating charges having the same polarity as that of the charges supplied from the charge input region are diffused in the diffusion layer.
[0018] According to the chemical/physical phenomenon detecting device of the first aspect defined as above, in the diffusion layer formed between the input charge control region and the sensing region, the potential in a neutral state of the diffusion layer is depart form or got off the potential of the sensing region. Here, the neutral state means a state in which no charge is present in the diffusion layer, and in this state, the potential of the sensing region is differ from the potential of the diffusion layer. That is, when electrons are adopted as the charges to be input, the potential of the diffusion layer is always higher than the potential of the sensing region. As a result of the doped diffusion layer, no potential barrier is formed between the charge supply control region and the sensing region.
[0019] According to the chemical/physical phenomenon detecting device defined in the first aspect, the electrode for controlling the potential of the charge removal well and wiring therefor are not required so that it is suitable for the requirement of high density integration in comparison with the conventional chemical/physical phenomena detecting device in which a charge removal well is formed to remove the potential barrier.
[0020] In the chemical/physical phenomenon detection device defined in the first aspect, the charge input (ID) region is also doped to be the same semiconductor type as the diffusion layer. For example, when the charges supplied from the charge input region are electrons, the charge input region and the diffusion layer are doped n-type to the semiconductor substrate. Therefore, in order to simplify the manufacturing process of the chemical/physical phenomenon detection device, it is preferable to dope the charge input region, the diffusion layer, and the charge accumulation region also using the same mask.
[0021] As a result, the chemistry/physical phenomenon detection device according to the second aspect of the present invention is defined as follows.
[0022] The chemical/physical phenomenon detection device according to claim 1 , wherein the same dopant is diffused into the diffusion layer and the charge input region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a cross-sectional view showing a configuration of a pH sensor according to a first embodiment of the present invention.
[0024] FIG. 2 is a schematic diagram showing a potential barrier formed when the diffusion layer is omitted from the pH sensor of the first embodiment.
[0025] FIG. 3 shows a planar structure of a pH sensor as well.
[0026] FIG. 4 shows the operation of the pH sensor of the first embodiment.
[0027] FIG. 5 is a cross-sectional view showing a configuration of a pH sensor according to a second embodiment of the present invention.
[0028] FIG. 6 is a schematic diagram showing a potential barrier formed when the diffusion layer is omitted from the pH sensor of the second embodiment.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
[0029] FIG. 1 shows the principle configuration of the chemical/physical phenomenon detection device 1 according to the first embodiment of the present invention.
[0030] The chemical/physical phenomenon detection device 1 is comprised of a silicon substrate 10 and a structure stacked on the silicon substrate 10 .
[0031] On the silicon substrate 10 , a charge input (ID) region 2 form which charges are input or supplied, an input charge control (ICG) region 3 , a diffusion layer 4 , a sensing region 5 , a charge transfer control (TG) region 6 , and a charge accumulation (FD) region 7 are partitioned in series. In the example of FIG. 3 , a rectangular sensing region is adopted and a diffusion layer 4 —input charge control region 3 —charge input region 2 are formed in order from a side of the sensing region as well as the charge transfer control region 6 and the charge accumulation region 7 are formed in order from another side of the sensing region 5 . All of regions can be aligned linearly. The section of each region is defined by the difference in semiconductor type on the surface of the semiconductor substrate 10 . For example, when electrons are used as charges, the charge input (ID) region 2 , the diffusion layer 4 and the charge accumulation (FD) region 7 are n+type regions, and the input charge control (ICG) region 3 and the sensing region 5 are p-type regions.
[0032] In the charge accumulation region 7 , a reset unit 8 for discharging the charges accumulated in the charge accumulation region 7 and a charge amount detection unit 9 for detecting an amount of charges in the charge accumulation region. A well-known conventional circuit is adopted for the reset unit 8 and the charge amount detection unit 9 .
[0033] A silicon oxide insulating layer 11 is stacked on the surface of the substrate 10 , on the layer 11 , an ICG electrode 15 is mounted at a position opposed to the input charge control region 3 and the potential of the input charge control region 3 is controlled by the ICG electrode 15 . A TG electrode 16 for controlling the potential of the charge transfer control region 6 is formed as well at a position opposed to the region 6 . In a portion corresponding to the sensing region 5 , a silicon nitride layer 13 is stacked as a sensitive layer. Since the silicon nitride layer 13 is formed after the ICG electrode 15 and the TG electrode 16 , the silicon nitride layer 13 also covers these electrodes.
[0034] An area and planar shape of each region, the amount of dopant introduced, and the material of the sensitive film can be arbitrarily designed in consideration of the object to be measured, measurement conditions, required sensitivity and the like.
[0035] Both the charge input region 2 , the diffusion layer 4 and the charge accumulation region 7 are doped with an n-type dopant. Before forming the insulating layer 11 , the dope is performed by masking the surface of the substrate 10 and implanting an n-type dopant. From the viewpoint of minimizing the number of times of mask processing, it is preferable to make the doping conditions be the same of the charge input region 2 , the diffusion layer 4 and the charge accumulation region 7 . As a result, the same dopant is introduced into these three regions at the same concentration by one doping treatment.
[0036] According to the chemical/physical phenomenon detecting device 1 shown in FIG. 1 , even if the silicon nitride layer 13 exists on the side surface of the ICG electrode 15 , the region of the substrate opposing thereto exists as the diffusion layer 4 . Since the dopant for increasing the potential of the diffusion layer 4 is diffused therein, the formation of the potential barrier is prevented.
[0037] FIG. 2 shows the potential of each region when the diffusion layer 4 is omitted. In FIG. 2 , reference numeral 20 denotes a potential barrier. In the example of FIG. 1 , since the diffusion layer 4 having a potential higher than that of the sensing region 5 is formed at the position where the potential barrier 20 is formed, the potential barrier 20 is buried therein and disappears. When holes are used as charges, the diffusion layer 4 has a potential lower than that of the sensing region 5 . In other words, the potential of the diffusion layer 4 is far from the potential of the sensing region 5 when viewed from the neutral state of the diffusion layer 4 .
[0038] As to the diffusion layer 4 , when the silicon nitride layer 13 covering the side surface of the ICG electrode 15 on the side of the sensing region 5 is projected onto the diffusion layer 4 below in FIG. 1 , the projected silicon nitride layer 13 is contained in the diffusion layer 4 .
[0039] FIG. 3 shows the plan structure of the chemical/physical phenomenon detection device 1 . As shown in FIG. 3 , the diffusion layer 4 is formed between the ICG region 3 and the sensing region 5 . Note that FIG. 1 is a cross-sectional structure taken along line I-I in FIG. 3 .
[0040] The width of the diffusion layer 4 can be arbitrarily set in consideration of etching conversion difference and mask shift. In this embodiment, the width of the diffusion layer 4 is set to 1.20 μm in the 2.0 μm process (that is, the minimum channel length is 2.0 μm).
[0041] Next, the operation of the chemical/physical phenomenon detection device 1 will be described with reference to FIG. 4 .
[0042] FIG. 4 ( a ) shows a reset step. In this reset step, the reset gate RG of the reset unit 8 is at a high potential, and the charges in the charge accumulation (FD) region (hereinafter may be simply referred to as “FD region”) 7 are discharged to the outside of the device.
[0043] FIG. 4 ( b ) shows a standby step. In this standby step, the reset gate RG of the reset section 8 becomes a low potential, so that charges can be accumulated in the FD region 7 .
[0044] FIGS. 4 ( c ) and ( d ) show the measurement step. As a premise of this step, the potential of the sensing region 5 varies depending on the external environment (the pH of the measurement object). First, as shown in FIG. 4 ( c ) , charges (in this case, electrons) are injected from the charge input (ID) region (hereinafter sometimes simply referred to as “ID region”) 2 and then charges go over an input charge control (hereinafter simply referred to “ICG region”) 3 and arrive or get into the sensing region 5 . After that, as shown in FIG. 4 ( d ) , when the charge supply from the ID region 2 is stopped, charges above the sensing region 5 are leveled by the ICG region 3 . At this time, the potential deference between the ICG region 3 and the sensing region 5 depends on the pH of the object to be measured, and an amount of charge corresponding to the potential difference remains on the sensing region 5 .
[0045] Since the potential of the diffusion layer 4 is set to be sufficiently higher than the potential of the sensing region 5 , no potential barrier is formed between the ICG region 3 and the sensing region 5 .
[0046] In the measurement step shown in FIG. 4 ( d ) , charges are also existed in the diffusion layer 4 , and the input charges remain on the layer 4 . An amount of charges, including the remaining charges on the diffusion layer, depending on the potential difference between the ICG region 3 and the sensing region 5 defines the pH value of the object to be measured. In other words, the charges existing in the charge well due to the diffusion layer 4 has no influence on the amount of charges that can define the pH value.
[0047] FIGS. 4 ( e ) and 4 ( f ) show the charge transfer step. The potential of the charge transfer control (TG) region 6 is raised and the charges remaining in the step of FIG. 4 ( d ) are transferred to and in the charge accumulation (FD) region 7 . Hereinafter the charge transfer (TG) region may be simply referred as TG region, and the charge accumulation (FD) region may be simply referred as FD region.
[0048] By repeating the steps in FIGS. 4 ( c ) to 4 ( f ), a small change in pH can be converted to a large change in charge amount.
[0049] In FIG. 4 ( g ) , the amount of charges in the FD region 7 is converted to an electric signal by the charge detection section 9 . This makes it possible to specify the pH value.
[0050] Hereinafter, the steps of FIG. 4 ( a ) to FIG. 4 ( g ) are repeated.
[0051] FIG. 5 shows an extended type chemical/physical phenomenon detecting device 101 . The same elements as those in FIG. 1 are denoted by the same reference numerals, and a description thereof will be partially omitted.
[0052] The chemical/physical phenomenon detection device 1 of the direct type in FIG. 1 and the chemical/physical phenomenon detection device 101 in FIG. 5 adopt the same configuration in the substrate 10 , and they are different in structure with regard to stacked layers formed on the silicon oxide insulating layer 11 on the substrate.
[0053] In the chemical/physical phenomenon detecting device 101 shown in FIG. 5 , a silicon oxide layer 102 is stacked on the entire surface of the insulating layer 11 , and a silicon nitride layer 113 as a sensitive layer is stacked on the surface of the silicon oxide layer 102 . The potential change of the silicon nitride layer 113 is transmitted to the sensing region defining electrode 123 via the conductive layers 115 , 116 , and 117 made of a metal material or the like buried in the silicon oxide layer 102 .
[0054] As a result, the potential of the silicon nitride layer 113 corresponding to the pH of the measurement object is reflected on the potential of the sensing region 5 .
[0055] It is to be noted that the extended type chemical/physical phenomenon detecting device 101 shown in FIG. 5 can be made by a conventional process and, of course, the silicon oxide layer can be formed in multiple layers (see Published Japanese Translation No. 2010-535360 The description of the literature is incorporated as part of this specification by reference.).
[0056] Even with the chemical/physical phenomenon detecting device 101 shown in FIG. 5 , unless the diffusion layer 4 is formed between the ICG region 3 and the sensing region 5 in the substrate 10 , as shown in FIG. 6 , the potential barrier 120 is formed to remain the charges on the sensing region and the charges thus remained may cause a false signal.
[0057] On the other hand, as shown in FIG. 5 , by forming the diffusion layer 4 between the ICG layer 3 and the sensing region 5 , the potential barrier 120 is not formed.
[0058] The chemical/physical phenomenon detecting device 101 also operates in the same manner as the chemistry/physical phenomenon detecting device in FIG. 1 (see FIG. 4 ).
[0059] The present invention is not limited to the description of the embodiment and examples of the invention at all. Various modifications are also included in the present invention as long as they can be easily conceived by those skilled in the art without departing from the spirit of the scope of claims.
EXPLANATION OF NUMERAL NUMBERS IN FIGS
[0000]
1 101 chemical/physical phenomena detection device
2 charge input (ID) region
3 input charge control (ICG) region
4 diffusion layer
5 sensing region
6 charge transfer control (TG) region
7 charge accumulation (FD) region
8 reset unit
9 charge amount detection unit
10 substrate
15 ICG electrode
16 TG electrode
115 , 116 , 117 conductive layer
123 sensing region defining electrode | Provided is a charge-transfer-type sensor suitable for high integration while eliminating a potential barrier. A sensor provided with a semiconductor substrate 10 partitioned into a sensing region 5 in which a potential varies in corresponding fashion to a variation in the external environment, a charge input region 2 for supplying charges to the sensing region 5 , an input charge control region 3 interposed between the sensing region 5 and the charge input region 2 , and a charge accumulation region 7 for accumulating electric charges transported from the sensing region 5 , the sensor for detecting the amount of electric charges accumulated in the charge accumulation region 7 , wherein a diffusion layer 4 is formed between the input charge control region 3 and the sensing region 5 of the substrate 10 , and dopants for producing charges having the same polarity as the charges supplied from the charge input region 2 are diffused in the diffusion layer 4. | 6 |
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure relates to an air duct device that can dissipate heat in a device.
[0003] 2. Description of Related Art
[0004] Electronic devices, such as computers, use heat dissipation assemblies for dissipating heat generated by components therein, thus preventing the components from becoming overheated. An air duct device is often used in a computer with a fan to assist in heat dissipation by guiding airflow. However, different sizes of electronic devices need different sizes of air duct devices, creating a need for a flexible air duct device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, all the views are schematic, and like reference numerals designate corresponding parts throughout the several views.
[0006] FIG. 1 is an exploded, isometric view of an exemplary embodiment of an air duct device, together with a cooling member.
[0007] FIG. 2 is an inverted view of FIG. 1 .
[0008] FIG. 3 is an assembled, isometric view of FIG. 1 .
[0009] FIGS. 4 to 5 are cross-sectional views of FIG. 3 , showing different states of use of the air duct device.
DETAILED DESCRIPTION
[0010] The present disclosure, including the accompanying drawings, is illustrated by way of examples and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.
[0011] Referring to FIGS. 1 and 2 , an exemplary embodiment of an air duct device is provided to conduct airflow for a cooling member 10 mounted in an electronic device (not shown). The air duct device includes a first air duct 30 and a second air duct 40 .
[0012] The cooling member 10 includes a fan 12 and a heat sink 14 . The fan 12 includes a first frame 122 and a second frame 124 opposite to the first frame 122 . Four substantially triangular tabs 126 respectively extend from four corners of each of the first and second frames 122 and 124 . A plurality of fasteners, such as screws, extends through the tabs 126 of the first frame 122 and engages with the heat sink 14 to fasten the fan 12 to a first end of the heat sink 14 . A mounting seat 18 fastened to a second end of the heat sink 14 opposite to the first end, is provided to fasten the cooling member 10 in the electronic device.
[0013] The first air duct 30 includes a substantially cylinder-shaped first main body 32 . The first main body 32 defines a passage 33 along an axis of the first main body 32 . The first main body 32 further defines two slide slots 320 opposite to each other and two rows of latching slots 324 opposite to each other along the axis of the main body 32 in a sidewall of the first main body 32 . Four substantially triangular tabs 34 equidistantly extend from a first end of the sidewall of the first main body 32 . A hook 36 extends down from each of the tabs 34 .
[0014] The second air duct 40 includes a substantially cylinder-shaped second main body 42 . The second main body 42 defines a passage 43 along an axis of the second main body 42 . A trumpet-shaped flange 44 slantingly extends up from a first end of the second main body 42 for increasing airflow of the passage 43 . The second main body 42 further equidistantly defines four substantially U-shaped through slots 420 in a sidewall of the second main body 42 . Two elastic latching hooks 424 opposite to each other are surrounded by two opposite through slots 420 of the four through slots 420 . The latching hooks 424 direct to a second end of the second main body 42 opposite to the first end. Two elastic guiding blocks 426 opposite to each other are surrounded by the other two opposite through slots 420 . The guiding blocks 426 direct to the first end of the second main body 42 .
[0015] Referring to FIGS. 3 to 5 , in assembly, the second main body 42 of the second air duct 40 is fit about the first main body 32 of the first air duct 30 through the passage 43 . An outer surface of the sidewall of the first main body 32 resists against an inner surface of the sidewall of the second main body 42 . The guiding blocks 426 of the second air duct 40 are slidably engaged in the corresponding slide slots 320 of the first air duct 30 , to make the second air duct 40 capable of sliding relative to the first air duct 30 along the slide slots 320 . The latching hooks 424 are latched to two corresponding opposite latching slots 324 , to fasten the second air duct 40 to the first air duct 30 . The tabs 34 of the first air duct 30 resist against the tabs 126 of the second frame 124 of the fan 12 . The hooks 36 of the first air duct 30 are latched to bottoms of the tabs 126 of the second frame 124 to fasten the first air duct 30 to the fan 12 .
[0016] In use, the latching hooks 424 are selectively latched to different two corresponding opposite latching slots 324 to adjust a length of the first air duct 30 exposed from the second air duct 40 , thereby changing the size of the air duct device, making it a universal duct system adaptable to many different size electronic devices.
[0017] In other embodiments, each tab 34 of the first air duct 30 defines a through hole, and correspondingly each tab 126 of the second frame 124 defines a fastening hole. A plurality of fasteners, such as screws, extends through the through holes of the first air duct 30 and engages in the fastening holes of the second frame 124 to fasten the first air duct 30 to the fan 12 .
[0018] It is to be understood, however, that even though numerous characteristics and advantages of the embodiments have been set forth in the foregoing description, together with details of the structure and function of the embodiments, the present disclosure is illustrative only, and changes may be made in details, especially in matters of shape, size, and arrangement of parts within the principles of the embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. | An air duct device includes a first air duct, and a second air duct slidably fitting about the first duct. The first air duct axially defines a first passage and defines a row of latching slots along an extending direction of the first passage. The second air axially defines a second passage. A latching hook is formed on the second air duct to be selectively latched to one of the latching slots. | 7 |
BACKGROUND OF THE INVENTION
This invention relates to a process for reducing residual monomers, diluents, solvents and other residues, particularly styrene and acrylonitrile monomers in styrenic polymers and more particularly to products such as packaging materials shaped from the melted polymer wherein free styrene and acrylonitrile monomers therein are reduced.
Thermoplastic polymer compositions, particularly those containing polymerized styrene, can be shaped into a wide variety of useful articles by conventional techniques such as extrusion, milling, molding, drawing, blowing, etc. Applications for such shaped articles are widespread and include structural units where properties such as low thermal deformation impact resistance (when a rubber component such as a butadiene polymer or copolymer is present) and high gloss are required. When acrylonitrile is present with styrene in a copolymer, the compositions uniquely exhibit excellent solvent resistance and low permeability to liquids and gases which make them especially useful as a lightweight substitute for glass in packaging and particularly in the manufacture of bottles, film, sheet, tubs, cups, trays and other containers for liquids and solids.
In manufacturing such polymer compositions, it is well known that free, unconverted, styrene monomer remains absorbed within the polymer particles when polymerization is not 100 percent complete and which is therefore present in products formed therefrom. Additionally present are small amounts of other monomers, solvents, oligomers, catalyst or volatile condensation products which may include for example acrylonitrile, ethylbenzene, toluene, etc. These materials may be detrimental to the ultimate product by reason of off-taste, toxicity, or downgrading of polymer properties via plasticization, depolymerization, etc. Also, government regulatory agencies are moving toward establishing maximum permissible levels of various monomers in the environment on grounds that excess levels may constitute a health hazard, and particularly regulations have been applied to packaging materials intended to contact food, beverages, pharmaceuticals, cosmetics and the like for which application of styrenic copolymers are especially suited.
Even though previously employed processes for vacuum stripping of polymer melts or solvent extracting finished polymer, as for example with alcohols or water, does reduce residual monomers, it has been found that free styrene and acrylonitrile monomers are thermally regenerated during subsequent high temperature operations such as melt processing. Depending on the level of monomers present in the polymer before melting, such an increase of regenerated monomer could lead to monomer leaching into foodstuffs which themselves simulate solvents and/or having the monomers released into the atmosphere around melt processing equipment.
Attempted alternatives to stripping the polymers have included for example chemically reducing various monomers with scavenger compounds. One example of such a prior art process may be found in U.S. Pat. No. 4,274,984.
It is undesirable in many food packaging applications to introduce scavenging compounds because they may not be inert to the other constituents of the polymer melt or may come in contact with the packaged food product. Furthermore, the prior art processes have been ineffective in reducing other residuals of the melt such as acrylonitrile and ethylbenzene to acceptable levels. Additionally, the prior art methods are relatively time consuming and fail to improve any property of the polymer other than residue reduction.
SUMMARY OF THE INVENTION
Now, however, a process has been developed to minimize such prior art shortcomings.
Accordingly, a principle object of this invention is to minimize generation of free styrene and acrylonitrile monomers during the conversion into melt-form of a polymer composition containing polymerized styrene.
Additionally, it is an object of this invention to negate the need for chemical scavengers in reducing residual free monomers in thermoplastic polymer packaging materials.
Another object is to reduce to extremely low levels the residual solvents, oligomers, catalyst or volatile condensation products that may be present particularly in styrenic polymer materials.
It is a still further object of the present invention to enhance the molecular weight distribution of the polymers and to do so more rapidly than by use of prior art methods.
These and other objects are accomplished by bringing the polymerizate, either in the solid or the molten state, into contact with carefully selected gases at or near the supercritical state.
From a product standpoint, a shaped article is provided which is formed of a thermoplastic polymer comprising in polymerized forms styrene and acrylonitrile containing reduced free styrene monomer, less than 0.3 ppm free acrylonitrile, and reduced ethylbenzene. By the term "reduced" is meant that amounts less than those attained by vacuum stripping, solvent extraction, or introduction of chemical scavengers into the same polymer are attained.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Polymers useful in the present invention may constitute either homopolymers or copolymers. It is particularly preferred that the polymers are ones which customarily generate free styrene monomer and contain at least about 10 percent by weight of polymerized styrene together with one or more copolymerized comonomers, as for example Acrylonitrile-Butadiene-Styrene, Styrene Acrylonitrile, Polystyrene, and High Impact Polystyrene. Other monomers may include:
(a) monovinylidene aromatic hydrocarbon monomers other than styrene of the formula: ##STR1## wherein R 1 is hydrogen, chlorine or methyl and R 2 is an aryl group of 6 to 10 carbon atoms and may also contain substituents such as halogen as well as alkyl groups attached to the aromatic nucleus, e.g. alpha methylstyrene, vinyl toluene, alpha chlorostyrene, ortho chlorostyrene, para methylstyrene, ethyl styrene, isopropyl styrene, dichlorostyrene, vinyl naphthalene, etc.;
(b) lower alpha olefins of from 2 to 8 carbon atoms, e.g. ethylene, propylene, isobutylene, butene-1, pentene-1 and their halogen and aliphatic substituted derivatives, e.g. vinyl chloride, vinylidene chloride, etc.;
(c) acrylic acid and methacrylic acid and the corresponding acrylate and methacrylate esters where the alkyl group contains from 1 to 4 carbon atoms, e.g. methyl acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, etc.;
(d) vinyl esters of the formula: ##STR2## wherein R 3 is hydrogen, an alkyl group of from 1 to 10 carbon atoms, an aryl group of 6 to 10 carbon atoms, e.g. vinyl formate, vinyl acetate, vinyl propionate, vinyl benzoate, etc.;
(e) vinyl ether monomers of the formula: H 2 C═CH--O--R 4 wherein R 4 is an alkyl group of from 1 to 8 carbon atoms, an aryl group of from 6 to 10 carbon atoms, an aryl group of from 6 to 10 carbon atoms or a monovalent aliphatic radical of from 2 to 10 carbon atoms, which aliphatic radical may be hydrocarbons or oxygen-containing, i.e. an aliphatic radical with ether linkages and may also contain other substituents such as halogen, carbonyl, etc. Examples of these monomeric vinyl ethers include vinyl methyl ether, vinyl ethyl ether, vinyl n-butyl ether, vinyl 2-chloroethyl ether, vinyl phenyl ether, vinyl cyclohexyl ether, 4-butyl cyclohexyl ether, and vinyl p-chlorophenylene glycol ether, etc.;
(f) olefinically unsaturated mononitriles having the formula: ##STR3## wherein R 5 is hydrogen, an alkyl group having 1 to 4 carbon atoms or a halogen. Such compounds include acrylonitrile, methacrylonitrile, ethacrylonitrile; propioacrylonitrile, alpha chloroacrylonitrile, etc.
Additional comonomers useful in the practice of this invention are those containing a mono- or di-nitrile function. Examples of these include methylene glutaronitrile, 2,4-dicyanobutene-1, vinylidene cyanide, crotonitrile, fumaronitrile, maleonitrile.
Preferred comonomers are the olefinically unsaturated mononitriles, monovinylidenes, aromatic hydrocarbons, lower alpha olefins, acrylic and methacrylic acid and the corresponding acrylate and methacrylate esters, with the olefinically unsaturated mononitrile hydrocarbons being more particularly preferred. Most specially preferred is acrylonitrile and alpha methylstyrene.
In styrenic compositions, the amount of comonomer can vary up to about 90% by weight based on the total weight of the styrenic polymer composition. Preferred styrenic compositions of this invention, for packaging applications requiring excellent oxygen and water vapor barrier properties in the packaging materials contain from about 10 to about 90% by weight of polymerized styrene monomer and from about 90 to about 10% by weight of polymerized acrylonitrile comonomer and more preferably from about 15 to about 45% by weight of styrene monomer and from about 85 to about 55% by weight of acrylonitrile monomer, all based on total polymer weight.
Styrenic polymers within the scope of this invention may also contain an elastomer in the form of a synthetic or natural rubber component such as polybutadiene, polyisoprene, neoprene, nitrile rubbers, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, chlorinated rubbers, etc. which are used to strengthen or toughen products such as shaped packaging materials. This rubber component may be incorporated into the styrene polymer by any of the methods well known to those skilled in the art, e.g. solution, mass or emulsion graft polymerization of at least some of the monomers of the styrene polymer in the presence of the rubber and subsequent blending of the grafted rubber and optionally additional matrix polymer by solution or melt blending techniques; or merely blending by such techniques the rubber and the styrene polymer. Especially preferred are polyblends derived by the first technique. Generally, the rubber component may comprise from 0 to about 25% and preferably from 5 to about 10% by weight of the styrenic polymer composition.
In the process of this invention, it has been discovered that selection of particular solvent gases at near critical to supercritical conditions drastically improves extraction while inhibiting depolymerization and decomposition of residual monomers. Suitable gases are those which are supercritical below the glass transition temperature (for solid extraction) of the polymers and which exhibit sufficient solvation of the key monomers. More specifically, the solvent gas should have a critical temperature in the range of +20° C. to -100° C. of the process temperature, more preferably -10° C. to -30° C. except in the case of CO 2 where the critical temperature may be as low as 210° C. below the process temperature if desired. The extraction temperature used in the process for molten polymers is largely determined by the supercritical temperature of the gas to be employed and may be adjusted according to other parameters well known to those skilled in the art such as desired polymer viscosity, polymer stability, safe operating pressures, etc. For solid state extraction, the critical temperature of the selected gas is desirably near room temperature but below the glass transition temperature of the polymer. The extraction temperature may vary from about 0° to 80° C., and preferably 10° C. to 30° C. above the critical temperature of the particular solvent gas chosen.
It is particularly preferred to employ the gases carbon dioxide (CO 2 ) and/or sulfur hexafluoride (SF 6 ) with the styrenic homopolymers and copolymers. The gases substantially reduce not only free styrene monomer, but also acrylonitrile, ethylbenzene and other low molecular weight constituents of the polymer to extremely low levels. Of additional advantage is the capacity of these solvent gases under supercritical conditions to effectively extract either polymer melts or the polymer in solid state.
When extracting non-styrenic polymers such as polyvinyl chloride, polyvinylidene chloride, polyesters, etc. it is especially preferred that the supercritical solvent gas be a halogenated hydrocarbon of 1 to 2 carbons, especially a fluorocarbon or fluorochlorocarbon such as the freons F-11, F-12, F-113 and F-21, i.e. CH 3 F, CCl 2 F 2 , CCl 2 FCCl 2 F, and CHCl 2 F, which have also been found to be equally effective on polymers in either solid or molten state. Also of use with such non-styrenic polymers are C 2-5 alkane or alkylene supercritical solvents, e.g. isopentane, pentane, butane, propane, propylene, ethylene, etc. Care should be exercised during the solid state extraction to select appropriate operating conditions correlated to temperatures as high as possible without softening or plasticizing the polymers being extracted. As a general rule, the extraction temperature should be as high as is practical in order to achieve minimum mixing viscosity and highest volatility of residues to be extracted. Temperatures must also remain below the depolymerization and decomposition temperatures of the polymers while optimizing the energy expended in the operation.
The pressure during extraction is subject to the temperature chosen for the extraction and further subject to equipment cost-effectiveness and safety. It is preferred that the operating pressure range from that of the critical pressure (P c ) of the solvent gas to that of 5 times the critical pressure (P c ) of such solvent gas, but more preferably from 1.2 P c to 3 P c .
The duration of the extraction may vary depending upon the degree of residue removal desired and the proximity of the extraction temperature to the decomposition temperature. Moreover, in said extractions, the particle size of the polymer being subjected to extraction will affect the time required for extraction. In normal operation, effective removal of residues from styrenic polymers is achieved in from about one to about 60 minutes.
Entrainers such as water, alcohols, N 2 O, C 2 H 4 , etc. may be used in amounts as low as 2-30%, preferably 5-15% of the weight of the solvent gas to enhance the extraction.
In addition to the removal of undesirable residues from the polymer, the present invention has the advantage of enhancing the molecular weight distribution of the polymer and so rapidly that the need for extraneous process techniques to accomplish this end are substantially negated. The resulting product usually contains substantially reduced amounts of low molecular weight components especially dimers or trimers and provides a relatively narrow molecular weight distribution product.
The process of this invention may be conducted by bubbling or sparging the gas through the polymerizate contained in a pressure vessel or if desired, an extruder. In one preferred embodiment of this invention, the supercritical solvent is passed through a battery of extractors containing polymer granules. The extracted residue is absorbed on adsorbents such as activated charcoal in a separate column. The remaining solvent is recirculated, and when the adsorbent approaches saturation, the adsorbent column is isolated and the residue desorbed thermally. The volatile residue containing extracted components may then be condensed in a cooler.
In one particularly preferred embodiment of the invention, the supercritical solvent is first added to the polymer melt in an extruder and mixed. The mixture is flashed or devolatilized to separate the residue and solvent from the polymer.
The forming operations used to prepare products within the scope of this invention such as the preferred polymeric packaging materials, e.g. sheet, tubs, trays, containers such as bottles, cans jars, etc., preforms for forming same and the like are procedures known in the the prior art. Examples of forming operations used to prepare shaped polymeric packaging materials include pelletizing, extrusion, blow molding, injection molding, compression molding, mill rolling, vacuum forming, plug assist thermoforming from sheet material, combinations of the foregoing and the like.
The present invention also contemplates the use of additives and ingredients in the polymeric compositions to provide desired modified properties. Examples of these ingredients include thermal stabilizers, light stabilizers, dyes, pigments, plasticizers, fillers, antioxidants, lubricants, extrusion aids, etc. If unaffected by supercritical extraction according to the invention, such additives may be added prior to the extraction step or more generally, afterwards.
The following examples are set forth in illustration of the invention and should not be construed as limitations thereof. All parts and percentages are by weight unless otherwise specified.
EXAMPLE I
Styrenic copolymers in granular form containing 76% polymerized styrene, 17% polymerized acrylonitrile and 7% butadiene having a melt flow index of 5.5 gm/10 minutes prepared by conventional polymerization methods were passed through a battery of five extractors, extracted under various conditions, and the residue analyzed. Results of the analysis appear in Table I.
TABLE I__________________________________________________________________________ Sample 1 2 3 4 5 6 7 8 9 10 11__________________________________________________________________________Solvent Carbon Dioxide Sulfur HexafluorideParticle Size, mesh 7 12 16 7 12 16 12 16 7 12 16Temperature, °C. 61 61 61 36 40 40 60 60 66Pressure, psi 1500 1500 1500 1520 1525 1525 1500 1500 1230Extraction Time, Min. 30 30 30 60 60 60 120 120 60Initial Residues, ppmAcrylonitrile (AN) 11 11Ethylbenzene (EB) 830 1030Styrene (St) 1540 1900Final Residues, ppmAN 8.5 1.0 0.7 4.5 1.4 0.7 0.1 <0.1 10.4 4.6 3.4EB 600 470 390 750 440 270 260 190 960 900 700St 1300 960 900 1500 810 600 400 160 1800 1700 1500__________________________________________________________________________
EXAMPLE II
Styrenic copolymers in granular form containing 75% polymerized styrene and 25% polymerized acrylonitrile having a melt flow index of 9.5 gm/10 minutes were prepared by conventional emulsion polymerization methods. The granules were passed through a battery of five extractors extracted under various supercritical conditions with carbon dioxide, and the residue was analyzed. The results of the analysis appear in Table II.
TABLE II__________________________________________________________________________ Sample 1 2 3 4 5 6 7 8 9__________________________________________________________________________Sovlent Carbon DioxideParticle Size, mesh 7 12 16 7 12 16 7 12 16Temperature, °C. 24 24 24 23 23 23 67 39.5 39.5Pressure, psi 200 200 200 860 860 860 1650 1525 1525Time, minutes 60 60 60 60 60 60 60 60 60Initial Residues, ppm AN = 17; EB = 500; St = 2000Final Residues, ppmAN 15 12 12 14 8.9 7.5 13.5 3.4 1.8EB 250 230 200 370 -- 180 260 160 110St 970 970 930 -- 810 790 840 560 500__________________________________________________________________________ | Bringing polymerizates, particularly those comprising styrene polymerized with an equal amount or more acrylonitrile and containing free styrene and acrylonitrile monomers, into contact with carefully selected gases in the near-critical to supercritical state substantially inhibits depolymerization and decomposition while substantially improving residue extraction. | 1 |
BACKGROUND OF THE INVENTION
The manufacture and repair of screens extending about the lower periphery of the main cylinder of a carding machine is a time consuming procedure requiring the talents of skilled craftsmen. The screen extends about 40 to 45 inches across the carding machine parallel with the axis of the main cylinder and the combined length of the front and rear portions of the card screen ranges from 50 to 64 inches. Each of the front and rear sections are formed in an arc when viewed from the side and the two sections include means for connecting them together beneath the axis of the main cylinder in conforming relation to the curvature of the main cylinder. The card screen comprising the front and rear sections is spaced a predetermined distance measured in thousandths of an inch from the lower periphery of the main cyclinder. As the main cyclinder rotates at speeds approximating thirty five to fifty miles per hour trash and non-spinable fibers are thrown from the lap and passed through the air space between adjacent grid bars in the card screen.
The front and back screens each comprise side ribs extending along opposite sides of the screen and transverse blanks extending between the side ribs adjacent the doffer and the lickerin. End bars are provided in the proximal ends of the front and rear screen portions adjacent their juncture beneath the axis of the main cylinder. The end bars are formed of sturdy stock to effectively brace and strengthen the screen at its center. A plurality of grid bars extend transversely of the screen in parallel relation to the end bars. The grid bars are spaced from each other a predetermined distance longitudinally of the screen and the number of grid bars varies from screen to screen and is dependent on the length of the screen the width and spacing of the bars and the air space between adjacent bars. There may be as many as 82 bars in a card screen. Each of these bars, according to the prior art, is soldered to the side ribs and to a central rib, if one is provided. The grid bars may be spaced from each other along the length of the card screen about 3/16s of an inch and there is an approximate equal spacing between the grid bars and the proximate blank and end bar.
It is important to satisfactory carding that the spacing be uniform and this requirement of careful spacing and the need for skilled soldering of each rib causes the manufacture and repair of card screens to be a time consuming process requiring the services of skilled craftsmen. Another factor contributing to the time and skill required in the conventional manufacture and repair of card screens is the need to straighten the screen to it's predetermined configuration after the screen has been distorted by heat from the soldering operation. The completed screen must have a smooth surface in order to prevent tagging by the fibers as they pass the screen and this need for a smooth surface requires the removal of excess solder by grinding and polishing, thereby adding to the time and skill required in the manufacture and repair of screens for carding machines. The extensive use made of solder in the manufacture and repair of card screens according to the prior art undesirably exposes the workers to lead molecules which are hazardous to the worker's health.
Card screens frequently require repair because a "choke" or large clump of fibers passes between the main cyclinder and the card screen. The resulting pressure frequently causes some of the grid bars to become bent and/or disconnected from the supporting side ribs and, if provided, the central rib. Because of the skill required in assembling the components of a card screen to the close tolerances needed for effective carding the damaged screens are generally returned to the same skilled craftsmen who manufactured the original screen. Repair is accomplished by the same time consuming alignment, soldering, straightening and polishing techniques as were required in the initial manufacture of the screen.
SUMMARY OF THE INVENTION
According the present invention, the grid bars are connected to the side ribs and the central ribs, if provided, by pins and without the need of solder. The ribs are prepunched to accommodate the supporting pins in a predetermined spacing so that the grid bars are automatically desirably spaced when the screen is assembled, thereby eliminating the prior art need for carefully spacing the bars relative to each other during assembly to acquire the proper air space between bars.
More specifically, the grid bars are equipped with sockets at their ends adjacent the side ribs and pins are passed through corresponding holes prepunched in the side ribs and the pins are received withing the sockets to support the grid bars. In card screens equipped with a center rib the ends of the grid bars on one side of the center rib are equipped with axially extending pins and the grid bars on the other side of the central rib are equipped with sockets to receive the pins on the first group of grid bars after the pins have penetrated a corresponding hole through the central rib.
By providing predetermined desirably spaced openings along the longitudinal extent of the side and central ribs, the bars are automatically spaced the desired distance from each other and aligned with the bars on the other side of the central rib, when assembled.
The end bars may be equipped at their outer ends with sockets like those in the grid bars and the side ribs may be prepunched to register with the sockets in the end bars. Similarly, if a center rib is used the central rib may be prepunched and the end bars on one side of the central rib may be equipped with pins to penetrate the opening in the central rib while the end bars on the other side of the central rib are equipped with sockets to receive the pin from the aligned end bar on the other side of the central rib.
Some card screens do not have central ribs and in those screens the grid bars and end bars extend uninterruptedly between the side ribs and there is no need for providing pins on some of the bars, assuming it is desired to use sockets at the ends of the bars to register with openings prepunched in the side ribs.
It is therefore an object of this invention to provide a novel arrangement which permits the bars and the side and center ribs of a card screen to be united in a more economical and reliable manner than has heretofore been possible.
It is another object of the invention to provide a card screen comprising component parts which may be assembled by unskilled labor.
It is a still further object of the invention to provide a novel method of assembling a card screen in a shorter time than has heretofore been possible.
A still further object of the invention is to provide a card screen and method of assembly which results in a more reliably united card screen than has heretofore been possible.
It is a more specific object of the invention to provide a card screen of the type described wherein the supporting side ribs and central rib, if used, are prepunched prior to assembly of the screen, the prepunching of the ribs defining desirably spaced groups of openings, an alternatively providing sockets or pins in the ends of the grid bars proximate to the side ribs, and, if sockets are provided, providing pins registrable with the prepunched openings in the side ribs and with the sockets in the grid bars.
It is another object of the invention to provide a method of assembling a card screen which significantly reduces the amount of soldering heretofore required in assembling card screens, thereby keeping the configuration of the screen within tolerance and not requiring as much straightening time after the screen is assembled.
It is further object of the invention to provide a method of assembling card screens which reduces the time heretofore required in grinding and polishing the completed screen to remove excess solder and make the screen desirably smooth for it's intended function.
A still further object of the invention is to provide a method and means for repairing card screens more accurately and in less time than has heretofore been possible.
Another object of the invention is to provide a method of manufacturing and repairing card screens which reduces the amount of solder required to assemble the screen and thereby reduces the exposure of the workers to lead molecules.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary side view of a carding machine with parts broken away and showing the relationship of a carding screen with the main cylinder;
FIG. 2 is a top plan view of the front and back card screen sections removed from the carding machine;
FIG. 3 is a fragmentary exploded schematic view perspectively illustrating the attachment of a pair of axially aligned grid bars to the side and center ribs of the screen;
FIG. 4 is a perspective view of a first female insert removed from one end of a grid bar;
FIG. 5 is a perspective view of a second female insert removed from the other end of the grid bar;
FIG. 6 is a perspective view of a male insert removed from an end of a grid bar;
FIG. 7 is a horizontal sectional view taken substantially along the lines 7--7 in FIG. 4;
FIG. 8 is an inverted end view of the first female insert looking at the end opposite that shown in FIG. 4;
FIG. 9 is a vertical sectional view taken substantially along the line 9--9 in FIG. 5;
FIG. 10 is an inverted end view of the second female insert looking at the end opposite that shown in FIG. 5;
FIG. 11 is a side view of the male insert shown in FIG. 6;
FIG. 12 is an inverted end view of the male insert looking at the end opposite that shown in FIG. 6;
FIG. 13 is a fragmentary exploded elevation illustrating the self alignment of opposed bars when the pin of the male insert penetrates the opening in the center rib and seats in the socket of an opposed second female insert during assembly of the screen;
FIG. 14 is a fragmentary exploded perspective view of an alternate form of the invention;
FIG. 15 is a fragmentary exploded schematic view perspectively illustrating the use of inserts to connect the end bars to the supporting side and center ribs;
FIG. 16 is a plan view of a carding screen without a central rib;
FIG. 17 is a fragmentary perspective view with parts broken away illustrating the use of prepunched side ribs and supporting pins to assemble grid bars and end bars in a carding screen without a central rib;
FIG. 18 is a fragmentary exploded perspective view of a modified form of the invention illustrating a grid bar with pins and sockets molded directly into the open ends of the bar; and
FIG. 18a is a transverse sectional view through an end portion of the grid bar shown in FIG. 18.
DETAILED DESCRIPTION OF THE INVENTION
Referring more specifically to the drawings, as best shown in FIG. 1, the numeral 10 broadly indicates a frame of a carding machine, only so much of the framework of the carding machine being shown as will be necessary to illustrate the essential features of the invention. The lickerin, main cylinder and doffer are schematically indicated at 11, 12 and 13, respectively. The main cylinder screen is broadly indicated at 14 and includes a front screen portion 14a and a back screen portion 14b. The screen, as best shown in FIG. 2, includes longitudinal side ribs 15 and 16 and transverse blanks 17 and 18 between which extends a longitudinal central rib 19.
A first group of longitudinally spaced bars 20 extend transversely from the side rib 15 to the central rib 19 and a second group of longitudinally spaced bars 21 extend transversely from the side rib 16 to the central rib 19. The bars 20 and the bars 21 are alike and are of any desired cross-sectional configuration; but in the embodiment illustrated, they are triangular in cross-section, as best shown in FIG. 3 and include opposed sides 22 and 23 which merge to define a pointed edge 24. The third side or face 25 of each bar 20 is opposite the pointed edge 24 and is desirably spaced from the main cylinder of the carding machine to separate foreign matter, lint and the like, from the fibers remaining on the main cylinder during the carding operation. The side 23 of each bar 20 and 21 is illustrated as including a seam 26 defined by overlapped ends of the material from which the bar is formed.
The bars 20 and 21 may be of a uniform dimension throughout their respective lengths and extend in uniformly spaced parallel relation to each other transversely of the screen to define a space of approximately 4.8 mm (3/16") bettween adjacent bars. This distance may be varied as desired. Alternatively, the bars 20 and 21 may be tapered inwardly from their respective junctures with the side frames toward their junctures with the center bar as described in U.S. Pat. No. 3,348,268 issued Oct. 24, 1967. End bars 27 extend transversely of the screen between side rib 15 and center rib 19. The end bars are positioned at the center of the screen in FIG. 2 and are proximate to each other when the front screen portion 14a and back screen portion 14b are assembled to form the complete screen. End bars 28 are aligned with the end bars 27 and extent between side rib 16 and center rib 19. The end bars are of tubular triangular configuration like the bars 20, 21, but the end bars 27, 28 are of sturdier stock and do not include a seam such as indicated at 26 on the grid bars 20, 21. The end bars are conventionally soldered to the side ribs 15, 16 and center rib 19 and effectively brace the center of the screen.
The structure of the screen thus far described is conventional and the invention resides in providing improved means for effectively joining the ends of the grid bars 20 and 21 and end bars 27, 28 to the side ribs 15, 16 and the center rib 19, if used.
As best seen in FIG. 3, each of the grid bars in the first group of bars 20 and each of the bars in the second group of bars 21 is of a triangular, tubular configuration and is open, as at 27, at each end. A first female insert broadly indicated at 30 is inserted in the open end 27 of each bar in the first group of bars 20 and in the open end 27 of each bar in the second group of bars 21 adjacent their respective junctures with side ribs 15 and 16.
Each insert 30 includes a generally T-shaped supporting frame broadly indicated at 31 shaped to conform to the configuration of and be received within the opening 27 in the ends of the bars 20, 21 adjacent the side ribs 15, 16. The frame 31 includes a top wall 32 which is parallel with and seated beneath the face 25 of a bar 20 or 21 when assembled. The top wall 32 forms the top of the T and merges with a perpendicular leg 33 at the medial portion of top wall 32. The leg 33 extends toward the pointed edge 24 of it's bar 20 or 21 when assembled. The first female insert 30 also includes a triangularly shaped head 34 including an upper edge portion 35 spaced outwardly in overhanging relation from the top wall 32 of frame 31 FIGS. 4 and 7). The head 34 tapers downwardly and inwardly from the upper edge portion 35 to a pointed end 36 spaced outwardly beyond the end of leg 33 remote from top wall 32. The leg 33 has a pair of circular bores or sockets 37 which also penetrate the head 34. The sockets are spaced along the leg 33 with one socket adjacent the top wall 32 and other socket about midway between the top wall 32 and the opposite end of leg 33. When the inserts 30 are assembled in the distal ends of respective bars 20, 21 the seams 26 on the bars 20, 21 fit in the space between the walls of the sockets 37. The ends of the top walls 32 of these inserts bear against the proximal inner surfaces of the grid bars 20, 21 and the opposite ends of the legs 33 bear against the inner surfaces of pointed edges 24 on the grid bars 20, 21 to frictionally retain the inserts in the grid bars with their heads 34 protruding beyond the bars in overlapping relation to the distal ends of the bars. The length of the supporting frames 31 from heads 34 is not critical except that they extend within the bars sufficiently to provide a stable frictional connection of the insert to the bar. The heads 34, of course, limit inward movement of the inserts 30 relative to respective bars.
Each side rib 15 and 16 includes equally spaced groups of transverse openings 38 arranged longitudinally along the side ribs and dimensioned to register with sockets 37 and receive pins 39 which are preferably annularly grooved as at G (FIG. 3) to increase frictional resistance. It is contemplated that in some instances the inserts 30 may include only a single socket 37 and the side ribs 15, 16 will include a like number of openings 38 to register with the sockets 37 in inserts 30. The term "group" refers to one or more openings in the ribs registrable with a like number of sockets in the inserts 30.
The inner end of each grid bar in the first group of bars 20 extends toward the center rib 19 and its open end 27 receives a second female insert 40. Each insert 40 includes an inner support frame 41 comprising top wall 42 and leg 33. Frame 41 is a substantial duplicate of the T-shaped frame 31 of the insert 30. The inner frame 41 fits within the open ends 27 of the bars 20 adjacent the center rib 19 and are frictionally retained therein by the engagement of the inner frames with the inner surfaces of the bars 20.
The second female inserts 40 differ from the first female inserts 30 only in that legs 43 have only a single relatively large diameter socket 47 which is located closely adjacent top wall 42 and extends through head 44 for registry with a selected one of a plurality of transverse openings 48 arranged along the length of central rib 19. The wall of the socket 47 frictionally engages the seam 26 on its bar 20 to help retain the frame 41 within the bar 20.
It is contemplated that one or more sockets 47 may be in the inserts 40 and a like number of openings 48 will be provided in the central rib for registry with the sockets 47. See FIG. 14. The openings 48 in the central rib 19 are referred to as groups of openings for each insert 40 even though in the illustrated form of invention each such group contains only one opening.
Each grid bar in the group of bars 21 has an insert generally indicated at 50 inserted in its open and 27 adjacent the center rib 19 and opposite first female insert 30. The inserts 50 include an inner support frame 51 which is like the frames 31 and 41 except the frame 51 does not have any cavity. It's leg 53 is preferably with a circular boss 57 for strengthening and for frictional engagement with the seam 26 on the bars to help retain the frame 51 within bar 21. A head 54 overlies the proximal end of frame 51 and a pin or pins 58 extend outwardly for registry with a corresponding group of openings 48 in central rib 19 and for reception in a corresponding number of sockets 47 in the inserts 40 (FIGS. 3 and 14).
METHOD OF ASSEMBLY
The end bars 27, 28 are identical to each other and may be equipped with properly dimensioned inserts like the inserts 30, 40 and 50 for registry with corresponding groups of openings in the side and center ribs. An end bar 27 is shown in FIGS. 15 and 17 being of heavier gauge material than the grid bars 20, 21 and the end portions 29 and 29' are simply overlapped instead of being turned on themselves to form a seam as are the end portions of the grid bars 20, 21. The overlapping end portion 29 rests against the inner frame of the corresponding insert 30, 40 or 50 like the seam 26 on the grid bars.
It is conventional practice to make some card screens without the center rib and such a card screen is illustrated at 14' in FIGS. 16 and 17. The card screen 14' includes the conventional side ribs 15', 16' and the conventional blanks 17' and 18', the blank 17' being omitted from the fragmentary view of FIG. 16. The screen 14' also includes the usual grid bars and end bars shown at 21' and 28' respectively in FIG. 16. The construction of the grid bars and end bars 21', 28' is like that of the grid bars 20, 21 and end bar 27 previously described.
The components of the screen 14' are assembled by use of inserts 30 at the ends of the grid and end bars to receive pins 39' extending through the side ribs 15', 16' in the manner previously described in connection with the first described embodiment of the invention.
A further modified form of the invention is illustrated in FIGS. 18 and 18a, wherein the inserts 30, 40 and 50 may be formed integral with the grid bars and end bars. The integral bars and inserts may be used in making the screen with the center rib 19 as illustrated in FIGS. 16 and 17, and reference is made to the screen components in FIGS. 18 and 18a with the same reference numbers as used to describe corresponding components in the first embodiment of the invention. The parts are assembled in the same way and no further description is deemed necessary to describe the assembly of the components with the integrated inserts and bars. Referring to FIG. 18a, it will be noted that the integrated insert 40' completely fills the tubular opening in the grid bar 21 and does not have the T-shaped inner frame of the insert 40.
After the components of the screen 14 comprising the side frames with their longitudinally spaced groups of openings 48, triangularly shaped tubular bars 20, 21, with their open ends 27 and the inserts 30, 40 and 50 have each been fabricated, the screen 14 is assembled by arranging successive pairs of bars 20 and 21 on opposite sides of the central rib 19, with the pins 58 on inserts 50 (FIGS. 3 and 14) aligned with openings 48 in the rib 19 and with the sockets 47 in the inserts 40 in registry with corresponding openings 48 in the central rib 19. The next step is to pass the pins 58 through the openings 48 and into the sockets 47 to connect the aligned pairs of bars 20, 21 in axial alignment with each other. Next, the sockets 37 in the distal ends of the aligned pair of bars 20, 21 are placed in registry with opposed openings 38 in side ribs 15, 16 and the pins 39 are passed through their respective side ribs and fastened in the sockets 37 to provide a stable connection of the pairs of aligned bars 20, 21 to side ribs and central rib.
The spacing of the groups of openings in the center rib 19 automatically aligns the bars and insures that they are arranged parallel to one another with the proper spacing between the bars on each side of the central rib, while at the same time insuring that the group of bars 20 on one side of the central rib 19 are axially aligned with their corresponding bars 21 on the other side of the central rib.
There is thus provided a novel arrangement for assembling the bars of a screen to the supporting frame which enables the screen to be formed more quickly with less skilled labor and which at the same time assures proper spacing and alignment of the bars relative to each other and to the frame of the screen. The automatic self-alignment and spacing is provided by the longitudinally spaced openings 38 in the side ribs 15 and 16 by the longitudinally spaced groups of openings 48 in the center rib. The sequential alignment of the bars with these openings and the placement of the pins through the openings automatically aligns and spaces the end bars and grid bars as they are attached to the ribs to form the screen. | A card screen with side frames and central rib penetrated with longitudinally spaced transverse openings and transverse bars equipped with pins and sockets supported in the transverse openings to secure the screen together without solder. | 3 |
BACKGROUND
Field of the Disclosure
This disclosure relates generally to a wall mount that allows the display of a football.
American football is one of several sports that uses a ball that is best described as a prolate spheroid which may defined as a spheroid with a polar axis (distance between the two tips of the ball) is greater than the equatorial diameter (diameter midway between the two tips). Sports that use a prolate spheroid shaped ball including American Football, Arena Football, Canadian Football, Rugby, and Australian Rules Football, among others. These balls are distinct from the ball known as a soccer ball in the United States which is a truncated icosahedron and not a prolate spheroid. While footballs used at the highest level of play and for commemorative purposes are made of a leather type material with separate lace material, there are also footballs made of a polymer (often called rubber) that are cast with the laces being protrusions in the cast surface rather than one or more components distinct from the leather panels.
FIG. 1 shows an American football such as the type used in the National Football League. The football 100 has a first pole 104 and a second pole 108 . The football has four panels 116 that are separated by seams 112 . The football 100 has a set of laces 150 that are gripped by the person throwing the football 100 . The set of laces 150 has one or more longitudinal laces 154 which straddle the equator of the football. The equator 120 on the football would be the latitude that is halfway between the poles 104 and 108 . A set of latitudinal laces 158 cross the longitudinal laces 150 at the ends and at several places along the longitudinal laces 154 . The latitudinal laces 158 are substantially orthogonal with the longitudinal laces 154
To provide context for this disclosure, it is useful to give an approximate size and weight for a football. According to the NFL Rule 2, section 1, the ball must be from a specified supplier and bear the signature of the commissioner of the NFL, but more relevant to this application the football must be an inflated 12½ to 13½ pound urethane bladder enclosed in a pebble grained, leather case (natural tan color) without corrugations of any kind. It shall have the form of a prolate spheroid and the size and weight shall be:
long axis: 11 to 11¼ inches; long circumference: 28 to 28½ inches; short circumference: 21 to 21¼ inches. weight: 14 to 15 ounces.
Regulation sized footballs used in an NCAA-regulated college football game are roughly:
long axis: 10½ to 11½ inches; long circumference: approximately 28 inches; and short circumference: approximately 21 inches.
The average is approximately 11.5 inches long by 6.7 inches in diameter. An NCAA football differs from the NFL ball in that it has two 1-inch white stripes that are three to three and one-quarter inches from either end of the ball and located only on the two panels adjacent to the laces. It can be up to one-half inch shorter along the long axis, but only slightly narrower than NFL balls.
There may be special commemorative balls that are of a different size, or balls intended for younger players that are smaller than the NCAA or NFL footballs. Footballs used in other types of football may have different aspect ratios (length to diameter).
There are a number of reasons why a person may wish to display a football rather than to simply store it with other outside gear. The football may have been the specific football used in an event of some significance such as a ball that was the 200 th catch by a particular receiver, or the game ball awarded to a star player in a college game.
Frequently, the football is not in compliance with all the rules to be a game ball but is instead a commemorative football. Many of these commemorative balls are regulation size but are provided with coloring, text, or emblems not found on a regulation ball. There are many different types of commemorative footballs. The football may be a special commemorative ball noting a special event such as a bowl game appearance. The football may have special coloring or other markings that notes that it is a football associated with a particular college (NCAA) or professional (NFL) team.
The football (commemorative or regulation ball) may be signed by a player or football coach and thus have significance much like any other autograph from a famous person.
SUMMARY OF THE DISCLOSURE
Aspects of the teachings contained within this disclosure are addressed in the claims submitted with this application upon filing. Rather than adding redundant restatements of the contents of the claims, these claims should be considered incorporated by reference into this summary.
This summary is meant to provide an introduction to the concepts that are disclosed within the specification without being an exhaustive list of the many teachings and variations upon those teachings that are provided in the extended discussion within this disclosure. Thus, the contents of this summary should not be used to limit the scope of the claims that follow.
Inventive concepts are illustrated in a series of examples, some examples showing more than one inventive concept. Individual inventive concepts can be implemented without implementing all details provided in a particular example. It is not necessary to provide examples of every possible combination of the inventive concepts provide below as one of skill in the art will recognize that inventive concepts illustrated in various examples can be combined together in order to address a specific application.
Other systems, methods, features and advantages of the disclosed teachings will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within the scope of and be protected by the accompanying claims.
BRIEF DESCRIPTION OF THE FIGURES
The disclosure can be better understood with reference to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosure. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.
FIG. 1 shows an American football such as the type used in the National Football League.
FIG. 2 shows a rear perspective view of a wall mount assembly 200 with a wall mount component 204 and a lace engagement component 304 .
FIG. 3 shows a front perspective view of the wall mount component 204 and the lace engagement component 304 .
FIG. 4 is a rear side perspective view of lace engagement component 304 .
FIG. 5 is a bottom side perspective view of lace engagement component 304 .
FIG. 6 is a top view of a football 100 engaged with a wall mount assembly 200 before the wall mount assembly 200 is placed over fastener heads protruding from a prepared wall.
FIG. 7 shows an observer 170 looking at a football 100 that is engaged with a wall mount assembly 200 .
FIG. 8 shows an alternative lace engagement component designed to display an autographed or otherwise annotated football.
FIG. 9 shows a back view of short wire lace engagement component.
FIG. 10 shows a side view of short wire lace engagement component.
DETAILED DESCRIPTION
FIG. 2 shows a rear perspective view of a wall mount assembly 200 with a wall mount component 204 and a lace engagement component 304 . The wall mount component 204 has a wall-facing side 208 to allow the wall mount component 204 to be placed flush against the wall. The wall mount component 204 may have one or more fastener engaging slots 212 that allow the wall mount component 204 and a football engaged with the lace engagement component 304 to fit over the head of a fastener (such as a screw head).
Frequently the smaller portion 216 of the one or more fastener engaging slots 212 is placed directly above the larger portion 220 of the fastener engaging slots 212 , but the orientation of the smaller portion 216 to the larger portion 220 may deviate plus or minus a small amount degrees from purely vertical alignment. Given the engagement of the lace engagement component 304 with the wall mount component 204 , the angle of the longitudinal centerline which runs internal to the football from the first pole 104 to the second pole 108 will be substantially orthogonal with the axis of the smaller portion 216 to larger portion 220 .
The wall mount component 204 has a ball facing side 240 (better seen in other figures) that is on the opposite side of the wall mount component 204 relative to the wall facing side 208 . The ball facing side 240 may be in a variety of configurations but is preferably adapted to nestle the curved surface of the football near the equator 120 of the football 100 .
One configuration for the ball facing side 240 is to have a set of fingers 244 extend outwards. While four fingers 244 are shown in FIG. 2 , different numbers of fingers could be used. Using two fingers may be adequate, but most configurations are going to use three or more fingers for stability. The fingers may have finger tips that are partial hemispheres. Appropriate choices for the geometry of the ball facing side 240 may allow for footballs from more than one regulation size to be used with a particular wall mount assembly. For example, a football mount may be used with either an NFL regulation sized football or an NCAA regulation sized football. Other mount assemblies adapted for other types of footballs such as balls used in Rugby or reduced sized commemorative balls may have different geometries as it is not essential that any one mount assembly must accommodate all possible prolate spheroid balls.
FIG. 3 shows a front perspective view of the wall mount component 204 and the lace engagement component 304 . The ball facing side 240 with four fingers 244 , and four finger tips 248 are visible. A cavity 252 within the ball facing side 240 may be covered with a cavity cover (not shown here). The cavity may be used to store a set of batteries and electronics for use in providing sound or LED illumination to add another aspect to the display.
One of skill in the art will recognize that the activation of a light may be done by a switch or via alternatives such as sound activation, wireless controller, light sensor (so a flashlight beam toggles the light on and off) or other activation tools known in the art. Deactivation could be achieved in the same manner as activation. For a process that plays a college fight sound or some other sound upon activation, deactivation may not be necessary as the sound may automatically terminate after the end of a set duration.
A printed circuit board with some or all of the relevant electronics could serve as the cavity cover. This printed circuit board may extend beyond the perimeter of the cavity wall.
FIG. 4 and FIG. 5 show views of a lace engagement component 304 . FIG. 4 is a rear side perspective view of lace engagement component 304 . FIG. 5 is a bottom side perspective view of lace engagement component 304 . The lace engagement component may be described as having a wall mount engagement 308 , a set of one or more lace engaging fingers 312 , 316 to engage one or more laces, and a set of spring portions 320 between the fingers 312 , 316 and the wall mount engagement 308 .
The lace engagement component 304 may be made from a range of suitable materials, preferably a material that will not oxidize or otherwise discolor the football 100 or laces 150 . Stainless steel such as T302 tempered stainless steel is one suitable material.
Those of skill in the art will recognize that a variety of wire stock may be used although the choice of wire stock may influence other aspects of the design. Here are the qualities of one wire stock (Inter Wire Group of Armonk N.Y. item number 0800SSCL) that has provided suitable results.
Description: 0.080 T302 S/S CL. Specification 1: ASTM-A313-08. Specification 2: SAE-J230-94. TENS STR MAX PSI—257,000. TENS STR MIN PSI—249,000.
FIG. 6 is a top view of a football 100 engaged with a wall mount assembly 200 before the wall mount assembly 200 is placed over fastener heads protruding from a prepared wall. A first seam 112 is essentially on the top of the football 100 as mounted. The a second seam, essentially 90 degrees offset from the first seam 112 runs among the fingers 244 extending from the ball-facing side 240 of the wall mount component 204 . One of skill in the art will recognize that the weight of the football 100 will cause the football 100 to drop both the football 100 and the distal end of the lace engagement component 304 after the user releases an engaged football 100 after engagement with the wall mount. The lace engaging fingers 312 and 316 are shown engaged to two latitudinal laces 158 per lace engaging finger. To engage a lace engaging finger 312 or 316 with one or more latitudinal laces 158 , the lace engaging finger 312 or 316 is moved by bending spring 320 and placing the tip 324 or 330 ( FIG. 4 ) under the one or more latitudinal laces 158 to be engaged. Releasing spring 320 provides sustained engagement with the one or more latitudinal laces 158 as one would need to work against the spring 320 in order to disengage the lace engaging finger 312 or 316 from the engaged latitudinal laces 158 .
FIG. 7 shows an observer 170 looking at a football 100 that is engaged with a wall mount assembly 200 with wall mount component 204 and lace engagement component 304 engaging a set of laces 150 on the top of the football 100 . Fasteners 178 connected to wall 182 engage with the wall mount component 204 to suspend the football 100 in a manner that is not visible to observer 170 as the football 100 is between the observer 170 and the wall mount component 204 in this head on line of vision 174 . The lace engaging fingers 312 and 316 may be set to engage latitudinal laces 158 on the wall side of the longitudinal laces 154 and thus should be obscured except when the observer 170 stands on a stool close to the wall 182 so that the observer 170 may view the football panel 116 located between the top of the football 100 and the wall 182 . Even when the observer 170 is in such a position, the lace engagement component 304 is not very noticeable. The lace engagement component 304 may optionally be made with lace colored lace engaging fingers 312 and 316 and spring section 320 made to blend with brown leather or whatever color is used for a commemorative football. The football 100 shown in FIG. 6 has the NCAA white stripes on two panels as discussed above.
Process of Mounting the Football.
Step 1. Find a desired location where you would want to mount the football 100 on the wall 182 .
Step 2. Place the wall mount component 204 against the wall 182 at the desired position including desired height from floor. Please note that the wall mount component 204 must be facing in the “UP” direction as noted on the wall mount component. Optionally, a stud sensor may be used to locate a wood stud to reduce the need for a dry wall anchor.
Step 3. Mark holes with a pencil through the smaller portion 216 of the fastener engaging slots 212 . Remove the wall mount component 204 from the wall 182 .
Step 4. Using a power drill and a 9/32″ drill bit, drill holes into wall 182 through marks made in Step 3. Add wall anchors to dry wall if you did not drill into a wood stud.
Step 5. Using a power drill or screwdriver, drive provided screws into studs (or drywall anchors) wall mount component 204 to the wall 182 . DO NOT tighten the screws to leave the wall mount component 204 easily removable from the wall 182 by using the fastener engaging slots 212 and sliding the wall mount component 204 upward releasing wall mount component 204 from the wall 182 .
Step 6. Remove the sliding the wall mount component 204 upward releasing wall mount component 204 from the wall 182 .
Step 7. Bend the spring portion 320 of the lace engagement component 304 as needed to guide the lace engaging fingers 312 and 316 through the latitudinal lace 158 as shown in FIG. 6 . For a football 100 such as shown in FIG. 6 , it may be desirable to engage the middle two latitudinal laces 158 in the four latitudinal on either side of the equator 120 . Release spring portion 320 .
Step 8. After engaging latitudinal laces 158 with the lace engaging fingers 312 and 316 of the lace engagement component 304 , engage the wall mount engagement 308 of the lace engagement component 304 with the wall mount component 204 by guiding the wall mount engagement 308 into a slot 280 in the wall facing side 208 the wall mount component 204 .
Step 9. Rotate the football 100 to allow viewing of the fastener engaging slots 212 with the screw heads protruding from the wall 182 . After engaging the screw heads, slide the wall mount component 204 downward to secure the wall mount component 204 to the wall 182 .
Step 10. Rotate the football 100 down allowing the football 100 to come to rest against the finger tips 248 of the wall mount component 204 .
NOTE: It is possible that the football 100 will not make contact with all four finger tips 248 of the wall mount component 204 after mounting as the rigidity of the wire in the lace engagement component 304 support the weight of the football 100 to hold the football 100 in a proper vertical orientation. Depending on the stiffness of the lace engagement component 304 , the football 100 may make contact with all, some, or none of the finger tips 248 of the wall mount component 204 . Thus, a designer may choose to have a wall mount component that lacks fingers 244 and rely on the stiffness of the lace engagement component 304 to hold the football 100 out from the wall.
Step 11. Step back and enjoy viewing the collectible football 100 that now appears to be suspended without support near the wall 182 as the wall mount component 204 is hidden from view by the football 100 .
Alternatives and Variations.
Short Wire for Autographed Footballs
FIG. 8 shows a computer aided drafting image of a football 1100 (without laces in this model) engaged with an alternative to lace engagement component 304 discussed above. This short wire lace engagement component 1304 is designed to engage laces not at the top of the football as discussed above but partially rotated towards the wall. This rotation allows panel 1404 which would typically have the insignia for the NFL, NCAA, or other relevant insignia for this football 1100 and panel 1408 which is typically unadorned when manufactured. This panel 1408 provides a place for a signature or other markings (such as Game Ball 2012 Champion Game) or other annotations. Rotating the laces towards the wall mount 204 to display the signature or other annotations on panel 1408 may be desired by some users for some footballs 1100 . Thus, a portion of the seam 1412 on the top side of panel 1408 is well above the longitudinal axis of the football 1100 that runs from pole 1104 to the opposite pole (not seen in FIG. 8 ).
FIG. 9 shows a view of short wire lace engagement component 1304 as viewed from the wall looking towards an engaged football 100 . FIG. 9 provides a side view of the same short wire lace engagement component. Visible in FIG. 9 and FIG. 10 are: the wall mount engagement section 1308 , lace engaging fingers 1312 and 1316 with tips 1324 and 1330 , and spring section 1320 . The geometry of the wall mount engagement section 1308 will need to cooperate with the wall mount component 204 .
Kits.
It is advantageous to sell a single wall mount component 204 with a set of two or more lace engagement components (such as 304 or 1304) that have the capacity to work with the one wall mount component 204 . This allows a purchaser of the wall mount kit to use the wall mount assembly to display a football 100 with the laces 150 on the top of the football 100 as shown in FIG. 7 or with the laces 150 rotated towards the wall mount component 204 to prominently display a lower panel with a signature or other notation.
A kit may include lace engagement components that are adapted for a football that has a different girth than found in the NCAA or NFL footballs, such as a rugby football or a smaller commemorative football. A kit may include screws and dry wall anchors.
Alternative Engagements with Laces
While the figures discussed above had lace engagement finger 312 engaged with different latitudinal laces 158 than were engaged by lace engagement finger 316 , this is not a requirement in order to use the teachings of the present disclosure. As one of skill in the art will appreciate, the lace engagement component 304 could be designed to allow lace engagement finger 316 to engage latitudinal laces 160 and 164 ( FIG. 6 ) and extend towards first pole 104 and allow lace engagement finger 312 to also engage latitudinal laces 160 and 164 and extend towards second pole 108 .
One of skill in the art will appreciate that an alternative lace engagement component 304 could be implemented to engage the longitudinal lace 154 in addition to or instead of engaging with one or more latitudinal lace 158 . For example the lace engaging fingers 312 and 316 that are adapted to engage one or more of the latitudinal laces 158 could be replaced with hooks (not shown) which may be substantially “U” shaped, that would engage one or more of the longitudinal laces 154 . However, the best use of the longitudinal laces 154 may be to help conceal lace engaging fingers 312 and 316 by routing the fingers under one or more of the longitudinal laces 154 . In most instances, engaging with the latitudinal laces 158 provides the best resistance to gravity and keeps the football 100 secured better than alternative engagements with the longitudinal laces 154 .
One of skill in the art will recognize that some of the alternative implementations set forth above are not universally mutually exclusive and that in some cases additional implementations can be created that employ aspects of two or more of the variations described above. Likewise, the present disclosure is not limited to the specific examples or particular embodiments provided to promote understanding of the various teachings of the present disclosure. Moreover, the scope of the claims which follow covers the range of variations, modifications, and substitutes for the components described herein as would be known to those of skill in the art.
The legal limitations of the scope of the claimed invention are set forth in the claims that follow and extend to cover their legal equivalents. Those unfamiliar with the legal tests for equivalency should consult a person registered to practice before the patent authority which granted this patent such as the United States Patent and Trademark Office or its counterpart. | A wall mount assembly for suspending a football near a wall to provide the illusion that the football is floating without support. The wall mount assembly having a lace engagement component for engaging with the laces of the football to hold the football to a wall engagement portion of the wall mount assembly. Lace engagement components can be selected to rotate the position of the laces from the top of the mounted football to closer to the wall behind the football if desired to display a signature on a football panel not adjacent to the laces. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates broadly to sculptured articles of manufacture and methods for making them. More particularly, this invention relates to turned figures based on a profile or a stylized representation of a figure. In addition, the invention relates to arrangements of said sculptured articles.
2. State of the Art
Decorative representations and methods for creating them have been granted utility patent protection since at least the nineteenth century. U.S. Pat. No. 629,312 to Beidler (issued in 1899) discloses a campaign torch with a three dimensional representation of two human heads, presumably candidates. U.S. Pat. No. 1,555,644 to Duncan (issued in 1925) discloses a multiple face doll, as does U.S. Pat. No. 1,618,772 to Merseburger (issued in 1927). U.S. Pat. No. 2,197,577 discloses a three dimensional ornament for use on a Christmas tree as well as a method for making it. In 1973 U.S. Pat. No. 3,762,084 issued to Jones for a fish mobile and a method for making the fish.
In 1980 DiMatteo was granted U.S. Pat. No. 4,180,930 for a reflected three dimensional display wherein half of two symmetrical portions of an object is cut or embedded in one surface of a block of transparent material with a reflective surface such that the cut or embedded image is reflected to give the appearance of the complete object.
U.S. Pat. No. 4,858,425 to Cheredaryk et al. (issued in 1989) discloses a reflecting ornament string in which a plurality of reflecting members are connected with a thin cord so as to permit free rotation of each member relative to others.
More recently, U.S. Pat. No. 6,858,422 to Spaar discloses a three dimensional hanging decoration which is made from a flat, lightweight sheet of flexible material.
It is therefore clear from the foregoing that art and technology have combined many times to produce something ornamental or artistic.
The history of the art of sculpture dates from the stone age when small statues were made of soft stone, ivory, or clay. These statues have been found and dated by archeologists. As the art progressed, different materials were employed including metals such as copper, gold and silver. Different methods of making sculptured articles were employed depending on the material used and the size of the sculpture. The sphinx was carved out of living rock whereas the Mount Rushmore sculpture was created with the aid of explosives. The most common methods of sculpture today include carving, casting, and molding. However, some metal sculpture is created by torch cutting and welding or by assembly with fasteners such as screws or rivets.
In 2004, a Colorado craftsman named Tom Beshara created a wooden object which is turned on a lathe. The object is a solid artifact which resembles an urn or a table leg or a candle holder. However, it creates, in negative space, on opposite sides of the artifact two identical two-dimensional profiles facing each other. The effect is based on an old optical illusion which requires you to look not at the object but to look at the negative space surrounding it. Thus, it is not really a sculpture of any thing. It is an object which defines a negative space wherein a human profile can be perceived.
For many years, the present inventor has been creating different art forms that express human identity. In recent years, the present inventor began to contemplate turned figures illustrating human identity. Before learning about Mr. Beshra's products, the present inventor conceived of the invention described and claimed herein.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide new methods for creating sculptured articles.
It is another object of the invention to provide artistic displays utilizing these new methods.
It is a further object of the invention to create sculptured articles which represent or suggest human identity.
In accord with these objects, which will be discussed in detail below, the methods of the invention include first creating a profile, either manually by drawing it or with the aid of backlit photography. The profile may be a realistic representation or an impressionistic representation. The profile is then used to create a solid sculpture which is a positive rotation of the profile about an axis. The resulting sculpture shows the profile on its three dimensional surface not in negative space. According to one method of the invention, the profile is used to create a CNC (computer numeric control) file which is used to operate a CNC equipped lathe. Suitable materials for use with the lathe include stone, metal, or wood depending on the cutting tool used in the lathe. The resulting article is a three dimensional object having a generally convex profile revolved about a longitudinal axis. When viewed, the profile can be seen in positive space over the entire surface of the object. According to another method of the invention, the profile is used to create a 3D printer file and a 3D printer is used to build an acrylic photopolymer sculpture. The resulting article is a three dimensional object having a generally convex profile revolved about a longitudinal axis. When viewed, the profile can be seen in positive space over the entire surface of the object.
In a first embodiment, a realistic profile of a human face is used and the resulting article resembles a bust but with only the features of the profile which are seen in positive space over the entire surface of the object. According to a second embodiment, a plurality of realistic human face profiles are acquired and connected to each other so that when the sculpture is complete one profile is atop the other somewhat like a totem pole. According to a preferred aspect of this embodiment, each of the faces are from members of the same family and the product is called the Family Totem™ or Revolutionary Family Toten™.
According to a third embodiment, a profile is obtained and a sculpture is created according to one of the methods described above. A plurality of objects are created in this manner and are suspended in a three dimensional field defined by a frame. According to a preferred aspect of this embodiment, the profiles are impressionistic profiles of nude female figures.
According to other embodiments of the invention, other profiles depicting or suggesting human identity are created and turned into solid objects according to one of the methods of the invention. Examples of profiles which depict or suggest human identity include, a profile of a city skyline (of the city where the person lives), a profile of a person's automobile, a profile of a person's hands, a profile of a person's pet, etc.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified flowchart showing a first method according to the invention;
FIG. 2 is a profile of a subject for a sculpture according to the invention;
FIG. 3 is a schematic illustration of a backlit photo of the subject of FIG. 2 ;
FIG. 4 is an illustration of the back lit profile with the rear of the head profile removed;
FIG. 5 is an illustration of the profile of FIG. 4 duplicated and the duplicate flipped;
FIG. 6 is an illustration of the two copies of the profile joined and a suitable base below them;
FIG. 7 is an illustration of the two copies of the profile and base all joined together providing a two dimensional representation of how the finished sculpture will appear;
FIG. 8 is an illustration of the profile which will be used to generate an appropriate computer file to complete the sculpture either with a printer or a lathe;
FIG. 9 is an illustration of a finished sculpture according to the invention where the shading illustrates shadow;
FIG. 10 is a simplified flow chart illustrating another method for making the sculpture of FIG. 9 ;
FIGS. 11 through 13 illustrate some of the steps in the process of making a totem sculpture according to the invention;
FIGS. 14 through 16 are computer generated images which illustrate impressionistic turned figures based on the human female body;
FIG. 17 is a photograph which illustrates a plurality of impressionistic figures arranged in a three dimensional space defined by a metal frame with the figures suspended by thin transparent filaments;
FIG. 18 is a two dimensional representation of a sculpture according to the invention of the profile of a city skyline;
FIG. 19 is a two dimensional representation of a sculpture according to the invention of the profile of a dog's head;
FIG. 20 is a two dimensional representation of a sculpture according to the invention of the profile of a penguin;
FIG. 21 is a two dimensional representation of a sculpture according to the invention of the profile of a horse head;
FIG. 22 is a three dimensional computer rendering of the expected appearance of a finished sculpture according to the invention; and
FIG. 23 is a photograph of three marble sculptures according to the invention.
DETAILED DESCRIPTION
Turning now to FIG. 1 and with reference to FIGS. 2 through 9 , a method of making a sculpture begins with obtaining a profile. One way of doing this is to obtain a backlit photograph of the subject as indicated at 10 in FIG. 1 . FIG. 2 illustrates a person's head and FIG. 3 schematically illustrates what a backlit photograph of the head looks like, i.e. no detail of the hairline, eye, ear, nose or mouth, just the outline or “profile”. FIG. 3 is schematic because in a backlit photograph the profile would be filled with black. According to presently preferred methods, the photograph is either digital or digitized with a scanner and processed with image editing software such as Adobe® Photoshop® from Adobe Systems, Incorporated. This is indicated at 12 in FIG. 1 . The processing steps include removing the black fill from the photo to obtain an image that looks like FIG. 3 . Alternatively, the black filled profile can be traced in a separate layer. In either case, the back of the profile is removed to create an image like that shown in FIG. 4 . The image of FIG. 4 is then copied and the copy is flipped horizontally as illustrated in FIG. 5 . The two copies are joined and an aesthetically suitable base is drawn as shown in FIG. 6 . The base is joined to the joined profiles as illustrated in FIG. 7 . FIG. 7 is a two dimensional approximation of what the final product will look like.
According to the invention, the profile will be revolved about an axis. Therefore, only half the profile is needed and thus, half may be removed leaving the profile of the head and base as shown in FIG. 8 . Those skilled in the arts of computer graphics and computer aided manufacturing (CAM) will appreciate that image editing software such as Adobe® Photoshop® create and manipulate “bitmap” images and that CAM machines work with “vector” images or numeric representations of an image. The bitmap image of FIG. 8 is thus converted to a vector image. This can be accomplished by importing it into a vector drawing program such as Adobe® Illustrator®. This step in the method is indicated at 14 in FIG. 1 .
A vector image such as an Adobe® Illustrator® file can then be imported into a 3D graphic modeling program such as Rhino™ from the McNeel Company. Thus, the vectorized image of FIG. 8 is imported into Rhino 3D as indicated at 16 in FIG. 1 . Using the vector information, the 3D modeling program can be given a command and will “render” an image on the computer screen that appears three dimensional. In this case, the command is “revolve” and the resulting image looks like FIG. 9 . The application of the revolve command is indicated at 18 in FIG. 1 . This step in the method will show the artist an approximation of what the finished product will look like at this point, the artist can go back and alter the profile in the vector drawing program to alter the look of the sculpture if desired.
Many 3D modeling programs allow for the creation of a CAM file such as an .stl (stereo lithography) file which can be used by a 3D printer. Thus, such a file is created as indicated at 20 in FIG. 1 .
According to the method illustrated in FIG. 1 , a rapid prototyping and manufacturing (RP&M) program, such as Magics X from Materialize, Leuven, Belgium, is used to control a 3D printer, such as the InVision™ 3-D Printers from 3D Systems, Inc. Thus, the file created at 20 in FIG. 1 is opened at 22 with Magics and sent to the 3D printer at 24 . These printers typically build acrylic photopolymer on a support to create the three dimensional article described by the computer file as indicated at 26 in FIG. 1 . When the printing is complete, the support is removed as indicated at 28 in FIG. 1 .
The method described with reference to FIG. 1 will produce an acrylic three dimensional object. However, the invention aims to create sculpture in different types of media and not just acrylic polymer. Thus, a second similar method is described in FIG. 10 which utilizes a CNC Lathe such as those available from Mori Seki Co. Ltd. and Nakamura-Tome Co. The method is substantially the same as that illustrated in FIG. 1 for method steps 110 through 118 . The method differs starting at 120 where a step file (.stp) is created and optionally converted at 122 to an ASCII G code file. The G code (or the .stp file) is sent to a CNC lathe at 124 which uses it to cut a block of spinning material at 126 . When the code is completed, the finished piece is removed at 128 . CNC lathes can be used to cut metal, wood, marble, and stone. Thus, the method of FIG. 10 provides a wider choice of materials for the sculptures.
FIGS. 11 through 13 illustrate some of the steps used to create a Family Totem™ according to the invention. The process described above with reference steps 10 and 12 in FIG. 1 are repeated for several profiles shown in FIG. 11 and the profiles are joined together and vectorized as shown in FIG. 12 . The vectorized image of FIG. 12 is then used in the process of either FIG. 1 or FIG. 10 to produce a solid turned sculpture as shown in FIG. 13 which is similar in some respects to a totem pole. According to the presently preferred embodiment, the totem comprises the profiles of several family members. Those skilled in the art may appreciate that the interface between the neck/shoulder/chest of one profile with the head of the profile below it may need to be “finessed” to achieve an aesthetically pleasing result.
Turning now to FIGS. 14-17 , another embodiment of the invention involves impressionistic profiles and a three dimensional arrangement of a plurality of sculptures. The turned sculptures shown in FIGS. 14-16 are based on an impressionistic representation of human female nude figures. As such, they are preferably drawn by hand rather than captured with digital photography. Alternatively, they may be captured with digital photography and then, after vectorizing, manipulated substantially. Because these figures lack a base, they are preferably displayed by suspending them. It is conceivable that a single such figure could be suspended or provided with a base, but an aspect of the invention shows a plurality of figures suspended in a three dimensional space which is defined by a frame as shown in FIG. 17 . It is not necessary that all of the figures be unique, nor is it necessary that they all be made of the same material or be the same color. Other sculpture made according to the methods of the invention may also benefit from a suspended display such as that shown in FIG. 17 .
FIG. 18 shows a two dimensional representation of a sculpture made according to the methods of the invention which is based on a city skyline. This can be more readily seen by viewing the sculpture with its axis or rotation aligned horizontally. Those familiar with the city will appreciate that the sculpture of FIG. 18 is based on the skyline of mid-town Manhattan, NYC. The sculpture of FIG. 18 is not shown with a base. A base may be provided or the sculpture may be suspended or it may be suspended in a three dimensional array with other related sculptures.
FIG. 19 shows a two dimensional representation of a sculpture made according to the methods of the invention which is based on a dog's profile. This sculpture could be provided with a base or made part of a totem.
FIG. 20 shows a two dimensional representation of a sculpture made according to the methods of the invention which is based on the profile of a penguin. This could identify a person who lives or has lived where penguins live.
FIG. 21 shows a two dimensional representation of a sculpture made according to the methods of the invention which is based on a horse's head.
FIG. 22 is a computer generated image such as the image generated at step 18 in FIG. 1 .
FIG. 23 is a photograph of three marble sculptures made according to the methods of the invention. Here the three “busts” are of family members
There have been described and illustrated herein several embodiments of methods for creating sculptures and sculptures created according to the methods. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as claimed. | A method for creating a sculpture includes obtaining a profile of a person or thing, using the profile to create a three dimensional object in which the profile is revolved about an axis. The resulting sculpture shows the profile in positive space over its entire surface. Exemplary apparatus for carrying out the method include 3D printers and CNC lathes. | 1 |
FIELD OF THE INVENTION
[0001] The present invention relates to novel tricarbocyanine-cyclodextrin(s) conjugates, and use thereof as diagnostic agents for kidney diseases.
BACKGROUND OF THE INVENTION
[0002] Fructans are used as markers in kidney diagnostics and in particular to determine the glomerular filtration rate (GFR) as a test for kidney function.
[0003] Fructans are straight or branched chain oligosaccharides and polysaccharides with an sucrose terminal end. Fructans can have different physical properties, such as water solubility depending on the degree of branching and polymerization. Fructans occur in plants as carbohydrate reserves. As a natural product the fructans have an unpredictable length.
[0004] The fructans inulin and sinistrin are used in particular as markers in kidney function tests. Inulin and sinistrin are composed of 10 to 40 fructose units with a corresponding molecular weight of 1600 to 6500 Da. After intravenous injection, inulin and sinistrin are neither changed nor stored in the organism, but they are filtered out by the kidney glomeruli and are not reabsorbed again in the tubuli. The filtration of the fructans may vary according to their size.
[0005] In order to assess kidney function, it is usual to determine the time variation of the concentration of the marker in the blood after intravenous injection of said marker. To do so, blood samples have to be drawn. The concentration marker in the blood may, for example, be determined by enzymatic methods, as described in Kuehnle et al., Nephron, 62, 104-107 (1992). This method is time consuming, very cumbersome and of limited use.
[0006] A simpler alternative, based on fluorescein isothiocyanate labelled inulin (FITC-inulin) was described (M. Sohtell et al., Acta Physiol. Scand 119, 313-316 (1983); J. N. Lorenz and E. Gruenstein, Am. J. Physiol. (Renal Physiol. 45) 276, F172-F177 (1999). With this approach, also, blood is sampled and the fluorescein label of the FITC-Inulin is determined in the plasma. A very serious problem with this approach is that hemolysis, occurring during blood sampling, affects the determination of the concentration. Moreover, hemoglobin absorbs the excitation light at 480 nm very well, so less light is emitted and the apparent concentration is lower than in reality.
[0007] A disadvantage of inulin and FITC-inulin for the clinical routine analyses is their very low solubility in water. Hence the preparations containing insulin and FITC-insulin have to be heated to 90° C. until complete dissolution (Rieg, T. A High-throughput Method for Measurement of Glomerular Filtration Rate in Conscious Mice. J. Vis. Exp. (75), e50330, doi:10.3791/50330 (2013)), as their aqueous solutions tend to crystallize during storage. Unfortunately, this causes a partial degradation of inulin to fructose. Furthermore, the solution has to be then dialysed for 24 hr at room temperature. This step is especially important to FITC-inulin in order to remove unconjugated FITC, but also the byproducts generated by the heating procedure. Dialysis substantially decreases the concentration of FITC-inulin. In addition, the low solubility of inulin and FITC-inulin makes it difficult to achieve a well defined concentration and to handle the marker during the injection.
[0008] Recently, a Cy5.5-inulin conjugate has been introduced by Perkin-Elmer (GFR-Vivo; application note by Peterson, J. D, Perkin-Elmer Corporation). An advantage of Cy5.5-inulin conjugate over FITC-inulin is related to the excitation/emission wavelengths of Cy5.5 (675/705 nm). The longer wavelength of Cy5.5 allows a deeper tissue penetration, but its use with a small animal imager requires the animals being anesthetized. Anesthesia, however, has an unpredictable impact on blood pressure (initial rise, decrease during the major phase of anesthesia, followed by a rise at the ending phase). Kidney perfusion and thus GFR are highly sensitive to blood pressure, with low blood pressure values resulting in low GFR values. Thus, a meaningful/reproducible GFR measurement is not possible under anesthesia.
[0009] A substantial improvement over the previous art was the introduction of a FITC-sinistrin conjugate as described in U.S. Pat. No. 6,995,019. This marker is much more water soluble than FITC-inulin and, in addition, no undesired circulatory reactions have been observed when using FITC-sinistrin. Furthermore its concentration change over time can be measured transcutaneously. There is, however, still the problem of the penetration depth into the skin at a given wave length (480 nm allow a depth of only a few mm) and thus the dosage of the marker has to be fairly high to obtain a clear (measurement) signal. Another problem of the transcutaneous measurement is skin pigmentation, as melanin in the skin absorbs light quite efficiently at 480 nm.
[0010] A major disadvantage of inulin and also sinistrin is that they are natural products; their composition is quite variable even within the same batch, and even more in different batches. For Regulatory Affairs this is not acceptable.
OBJECT AND SUMMARY OF THE INVENTION
[0011] The object of the present invention is to provide a novel substance which can be used as marker in a kidney function test which overcome the disadvantages of the markers known in the prior art.
[0012] According to the invention, the above object is achieved thanks to the matter specified in the ensuing claims, which are understood as forming an integral part of the present invention.
[0013] The invention relates to fluorescent tricarbocyanine-cyclodextrin(s) conjugates as markers for kidney function tests in mammals.
[0014] An embodiment of the present invention relates to a fluorescent compound of formula (I)
[0000] F-L n -CD n (I)
[0015] wherein
[0016] F is a tricarbocyanine residue of formula (II)
[0000]
[0017] wherein
[0018] R 1 and R 2 are independently selected from H, SO 3 H, CO 2 H, SO 2 NH 2 , CH 2 COOH, NH 2 , NHCOCH 2 I, NO 2 , Br, Cl, CH 3 ;
[0019] R 3 and R 4 are independently selected from C 1-4 alkyl, (CH 2 ) 3 C≡CH, (CH 2 ) 4 C≡CH (CH 2 ) 5 COOH, (CH 2 ) 3 SO 3 H, (CH 2 ) 4 SO 3 H, (CH 2 ) 3 NH 2 , (CH 2 ) 4 NH 2 , (CH 2 ) 3 N + (CH 3 ) 3 , (CH 2 ) 5 N + (CH 3 ) 3 , (CH 2 ) 3 N 3 , (CH 2 ) 4 N 3 , (CH 2 ) 3 NHCOCH 2 I, (CH 2 ) 4 NHCOCH 2 I; (CH 2 CH 2 O) 2 CH 3 , (CH 2 CH 2 O) 3 CH 3 (CH 2 CH 2 O) 4 CH 3 ;
[0020] R 5 , is H, Cl, or
[0000]
[0021] wherein
[0022] X is selected from NH, O, S;
[0023] j is an integer from 1 to 4;
[0024] k is an integer from 1 to 4;
[0025] CD is a cyclodextrin residue of formula (III)
[0000]
[0026] wherein
[0027] m is and integer equal to 6, 7 or 8,
[0028] R′, R″, R′″ are independently selected from OH, OCH 3 , OCH 2 CH 3 , OCH 2 CHOHCH 3 , OCHOHCH 3 , OCH 2 COOH, O(CH 2 ) 4 SO 3 H, N 3 , NH 2 , NHCOCH 3 , OCH 2 C≡CH, SH;
[0029] L is a linker group resulting from the coupling of the tricarbocyanine of formula (II) to the cyclodextrin(s) of formula (III) according to the following Table 1:
[0000]
Functional group of
Functional group
the tricarbocyanine
of the cyclodextrin
(F) in any
(CD) in any
of the groups
of the groups
R 3 , R 4 or R 5
R′, R″ or R′′′
Linker group (L)
COOH
OH
—C(O)O—
COOH
NH 2
—C(O)NH—
NCS
OH
—NC(S)O—
NCS
NH 2
—NC(S)NH—
NH 2
COOH
—NHC(O)—
NHCOCH 2 I
SH
NHC(O)CH 2 S—
C≡CH
N 3
N 3
C≡CH
dichlorotriazine
OH
dichlorotriazine
OH, OH
dichlorotriazine
OH, NH 2
[0030] n is an integer from 1 to 4,
[0031] and salts thereof.
[0032] A further embodiment of the present invention relates to a diagnostic formulation comprising at least one fluorescent compound of formula (I) for use in diagnostic tests for determining the kidney function parameters, preferably the glomerular filtration rate (GFR), of a mammal.
[0033] A still further embodiment of the present invention relates to a diagnostic method for determining whether a mammal suffers from chronic kidney diseases, wherein the method comprises i) administering at least one fluorescent compound of formula (I) or a diagnostic formulation comprising at least one compound of formula (I) to the mammal, and ii) detecting and measuring the fluorescence emitted by the fluorescent compound, wherein the measured fluorescence directly correlates (i.e. correlates in a proportional way) with the kidney function, particularly the glomerular filtration rate (GFR), of the mammal.
[0034] A further embodiment of the present invention relates to a method for screening pharmaceutical compounds suitable for treatment of chronic kidney diseases, wherein the method comprises:
[0035] i) administering to an animal model of chronic kidney disease a pharmaceutical compound and at least one fluorescent compound of formula (I), wherein the fluorescent compound is administered subsequently to the pharmaceutical compound;
[0036] ii) measuring the glomerular filtration rate by detecting and measuring the fluorescence emission of the at least one fluorescent compound of formula (I), wherein the detection and the measurement of the fluorescence comprises the detection and the measurement of the fluorescent emission emerging from the skin of the animal model in response to excitation with a red light or near infrared light source; and
[0037] iii) selecting the pharmaceutical compound that increases glomerular filtration rate (GFR).
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The invention will now be described, by way of example only, with reference to the enclosed figures of drawing, wherein:
[0039] FIG. 1 : Structural formula of 2-hydroxypropyl-β-cyclodextrin (HβCD).
[0040] FIG. 2 : Absorption spectrum of ABZWCY-HβCD in methanol.
[0041] FIG. 3 : Emission spectrum of ABZWCY-HβCD in methanol.
[0042] FIG. 4 : Schematic diagram of the transcutaneous measuring device.
[0043] FIG. 5 : Application to a rat of the transcutaneous measuring device.
[0044] FIG. 6 : Plasma clearance kinetics of ABZWCY-HβCD: (a) 1 exponential fitting (1e); 3 exponential fitting (3e).
[0045] FIG. 7 : Plasma clearance kinetics of ABZWCY-HβCD in the presence of Probenecid: (a) 1 exponential fitting (1e); 3 exponential fitting (3e).
DETAILED DESCRIPTION OF THE INVENTION
[0046] In the following description, numerous specific details are given to provide a thorough understanding of embodiments. The embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the embodiments.
[0047] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0048] The headings provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0049] The invention relates to fluorescent tricarbocyanine-cyclodextrin(s) conjugates as markers for kidney function tests.
[0050] These fluorescent conjugates, that are the object of the present invention, are represented by the general formula (I)
[0000] F-L n -CD n (I)
[0051] wherein
[0052] F is a tricarbocyanine residue of formula (II)
[0000]
[0053] wherein
[0054] R 1 and R 2 are independently selected from H, SO 3 H, CO 2 H, SO 2 NH 2 , CH 2 COOH, NH 2 , NHCOCH 2 I, NO 2 , Br, Cl, CH 3 ;
[0055] R 3 and R 4 are independently selected from C 1-4 alkyl, (CH 2 ) 3 C≡CH, (CH 2 ) 4 C≡CH (CH 2 ) 5 COOH, (CH 2 ) 3 SO 3 H, (CH 2 ) 4 SO 3 H, (CH 2 ) 3 NH 2 , (CH 2 ) 4 NH 2 , (CH 2 ) 3 N + (CH 3 ) 3 , (CH 2 ) 5 N + (CH 3 ) 3 , (CH 2 ) 3 N 3 , (CH 2 ) 4 N 3 , (CH 2 ) 3 NHCOCH 2 I, (CH 2 ) 4 NHCOCH 2 I; (CH 2 CH 2 O) 2 CH 3 , (CH 2 CH 2 O) 3 CH 3 (CH 2 CH 2 O) 4 CH 3 ;
[0056] R 5 , is H, Cl, or
[0000]
[0057] wherein
[0058] X is selected from NH, O, S;
[0059] j is an integer from 1 to 4;
[0060] k is an integer from 1 to 4;
[0061] CD is a cyclodextrin residue of formula (III)
[0000]
[0062] wherein
[0063] m is and integer equal to 6, 7 or 8,
[0064] R′, R″, R′″ are independently selected from OH, OCH 3 , OCH 2 CH 3 , OCH 2 CHOHCH 3 , OCHOHCH 3 , OCH 2 COOH, O(CH 2 ) 4 SO 3 H, N 3 , NH 2 , NHCOCH 3 , OCH 2 C≡CH, SH;
[0065] L is a linker group resulting from the coupling of the tricarbocyanine of formula (II) to the cyclodextrin(s) of formula (III) according to the following Table 1:
[0000]
Functional group of
Functional group
the tricarbocyanine
of the cyclodextrin
(F) in any
(CD) in any
of the groups
of the groups
R 3 , R 4 or R 5
R′, R″ or R′′′
Linker group (L)
COOH
OH
—C(O)O—
COOH
NH 2
—C(O)NH—
NCS
OH
—NC(S)O—
NCS
NH 2
—NC(S)NH—
NH 2
COOH
—NHC(O)—
NHCOCH 2 I
SH
NHC(O)CH 2 S—
C≡CH
N 3
N 3
C≡CH
dichlorotriazine
OH
dichlorotriazine
OH, OH
dichlorotriazine
OH, NH 2
[0066] n is an integer from 1 to 4,
[0067] and salts thereof.
[0068] Dyes belonging to the class of cyanines have already found some use in clinical diagnostics; in particular, Indocyanine Green has been used for kidney function test and fluorescence angiography for more than 30 years.
[0069] Tricarbocyanine dyes absorb and emit light in the near-infrared region (NIR) (650-900 nm). Tricarbocyanine dyes are especially suitable for in vivo imaging, diagnostics and even therapeutics, since biological tissues are relatively poor absorbers in the near-infrared spectral region, and infrared light can penetrate deeply in such tissues; in addition, these dyes do not give origin (or at very low amount) to auto-fluorescence in the near-infrared spectral region.
[0070] Cyclodextrins (CD) are cyclic oligosaccharides produced by the enzymatic degradation of starch. Depending on reaction conditions, three main CDs can be obtained α, β and γ; they consist of 6, 7 or 8 glucopyranose units. They are shaped as a truncated cone, with hydroxyl groups on each side. Their cavity is constituted by the glucosidal moieties. These three dimensional structures result in a high external hydrophilicity and internal hydrophobicity.
[0071] In one embodiment, CDs are selected from β- and γ-cyclodextrins, that is, CD in which m parameter of formula (III) has a value about of 7 (β-cyclodextrin) or 8 (γ-cyclodextrin), respectively.
[0072] While the water solubility of natural CDs is limited, chemical substitution at the 2-, 3- and 6-hydroxyl sites (i.e., when R′, R″ and R′″ are OH) greatly increases solubility. Most of cyclodextrins modified in this way, are able to achieve a 50% (w/v) concentration in water.
[0073] In one embodiment, at least one of the groups R′, R″, R′″ of formula (III) is selected from OCH 3 , OCH 2 CH 3 , OCH 2 CHOHCH 3 , provided that at least one group R′, R″, R′″ is OH.
[0074] In a preferred embodiment, R′ and R″ are OH, R′″ is selected from OCH 3 , OCH 2 CH 3 , OCH 2 CHOHCH 3 , preferably is OCH 2 CHOHCH 3 , in which the substitution degree of R′″ is between 0.5 and 1.5 per unit of formula (III).
[0075] It is known to the skilled technician that the substitution of the groups R′, R″, R′″ of a cyclodextrin molecule, for example with groups OCH 3 , OCH 2 CH 3 , OCH 2 CHOHCH 3 , is partial, i.e. it that takes place only in some of the m structures of formula (III) constituting the cyclodextrin with a substitution degree between 0.5 and 1.5 substituents per unit of formula (III); in other words, some groups R′, R″, R′″ in some of the m structures of formula (III) are not replaced, or are OH groups, and are the ones predominantly, though not exclusively, involved in the conjugation with tricarbocyanine molecules of formula (II).
[0076] In a further preferred embodiment, cyclodextrins of formula (III) are selected from 2-hydroxypropyl cyclodextrins (HCD), and in particular 2-hydroxypropyl-3-cyclodextrin (HβCD, whose chemical structure is shown in FIG. 2 , and 2-hydroxypropyl-γ-cyclodextrin (HγCD).
[0077] HβCD and HγCD have been found to be non-toxic in mice and rabbits [Pitha, J. “Amorphous water soluble derivatives of cyclodextrins: non toxic dissolution enhancing excipients.” J. Pharm. Sci. 1985, 74, 987]. HβCD and HγCD are widely used to improve the water solubility of drugs.
[0078] HβCD and HγCD represent advantageous substitutes of fructans, such as inulin and sinistrin, as components of fluorescent markers for the determination of GFR, as they are relatively inexpensive, non-toxic, structurally well-defined, synthetic products, with a strong solubilizing power.
[0079] In an embodiment, the conjugate of formula (I) presents from 1 to 4 linker groups L to allow conjugation of 1 to 4 cyclodextrin molecules to one tricarbocyanine molecule.
[0080] In a preferred embodiment, R 1 and R 2 groups are independently selected from H, SO 3 H, CO 2 H.
[0081] In a preferred embodiment, R 3 and R 4 groups are independently selected from methyl, ethyl, (CH 2 ) 5 COOH, (CH 2 ) 4 SO 3 H, (CH 2 ) 3 N + (CH 3 ) 3 .
[0082] In a preferred embodiment, R 5 group is selected from H, Cl, or
[0000]
[0083] In a preferred embodiment, the linker group L is selected from an ester, an ether, an amide, a thiocarbamate, a thiourea, a thioether, a 1,2,3-triazole, or
[0000]
[0084] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (IV):
[0000]
[0000] wherein CD is 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linker L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 1) is an ester bond formed in the coupling reaction of the carboxyl group of the tricarbocyanine (corresponding to carboxyl group of R 5 group=
[0000]
[0000] with a residue group R′″═OH of CD.
[0085] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (V):
[0000]
[0000] wherein CD is 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linker L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 1) is an ester bond formed in the coupling reaction of the carboxyl group of the tricarbocyanine (corresponding to carboxyl group of R 5 group=
[0000]
[0000] with a residue group R′″═OH of CD.
[0086] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (VI):
[0000]
[0000] wherein CD is 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linker L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 1) is an ester bond formed in the coupling reaction of the carboxyl group of the tricarbocyanine (corresponding to the carboxyl group of R 5 group=
[0000]
[0000] with a residue group R′″═OH of CD.
[0087] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (VII):
[0000]
[0000] wherein CD 1 and CD 2 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 2) are ether bonds formed in the coupling reaction of the R 5 group=dichlorotriazine of the tricarbocyanine with a residue group R′″═OH of CD 1 and CD 2 , respectively.
[0088] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (VIII):
[0000]
[0000] wherein CD 1 and CD 2 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 2) are ester bonds formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl group of the R 3 and R 4 groups=(CH 2 ) 5 COOH) with a residue group R′″═OH of CD 1 and CD 2 , respectively.
[0089] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (IX):
[0000]
[0000] wherein CD 1 and CD 2 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 2) are ester bonds formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl group of the R 3 and R 4 groups=(CH 2 ) 5 COOH), with a residue group R′″═OH of CD 1 and CD 2 , respectively.
[0090] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (X):
[0000]
[0000] wherein CD 1 , CD 2 and CD 3 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 3) are ester bonds formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl group of the R 3 and R 4 groups=(CH 2 ) 5 COOH and the carboxyl group of the
[0000]
[0000] with a residue group R′″═OH of CD 1 , CD 2 , and CD 3 , respectively.
[0091] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (XI):
[0000]
[0000] wherein CD 1 , CD 2 and CD 3 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 3) are ester bonds formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl group of the R 3 and R 4 groups=(CH 2 ) 5 COOH) and the carboxyl group of
[0000]
[0000] with a residue group R′″═OH of CD 1 CD 2 and CD 3 . respectively.
[0092] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (XII):
[0000]
[0000] wherein CD 1 and CD 2 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 2) are ester bonds formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl group of the R 3 and R 4 groups (CH 2 ) 5 COOH) with a residue group R′″═OH of CD 1 and CD 2 , respectively
[0093] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (XIII):
[0000]
[0000] wherein CD 1 and CD 2 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 2) are ester bonds formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl group of the
[0000]
[0000] with a residue group R′″═OH of CD 1 and CD 2 , respectively.
[0094] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (XIV):
[0000]
[0000] wherein CD 1 , CD 2 , CD 3 and CD 4 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 4) are ester bonds formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl group of the
[0000]
[0000] with a residue group R′″═OH of CD 1 and CD 2 , CD 3 and CD 4 , respectively.
[0095] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (XV):
[0000]
[0000] wherein CD 1 and CD 2 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 2) are ester bonds formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl groups of the
[0000]
[0000] with a residue group R′″═OH of CD 1 and CD 2 , respectively
[0096] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (XVI):
[0000]
[0000] wherein CD 1 and CD 2 are, independently, 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linkers L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 2) are ester bonds formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl groups of the
[0000]
[0000] with a residue group R′″═OH of, CD 1 and CD 2 . respectively.
[0097] In a preferred embodiment, the fluorescent tricarbocyanine-cyclodextrin conjugate is a compound of formula (XVII):
[0000]
[0000] wherein CD is a 2-hydroxypropyl-β-cyclodextrin (HβCD) or 2-hydroxypropyl-γ-cyclodextrin (HγCD) and the linker L of Formula (I) (corresponding to the value of the n parameter of formula (I) equal to 1) is an ester bond formed in the respective coupling reaction of a carboxyl group of the tricarbocyanine (corresponding to the carboxyl group of the
[0000]
[0000] with a residue group R′″═OH of CD.
[0098] In a further embodiment, the present invention relates to the use of at least one fluorescent compound of formula (I) or a diagnostic formulation comprising at least one fluorescent compound of formula (I) in kidney diagnostics, preferably in measuring the glomerular filtration rate (GFR), in a mammal.
[0099] In an embodiment, the mammal is a mouse, a rat, a guinea pig, a cat, a dog, a sheep, a goat, a pig, a cow, a horse, a primate.
[0100] In a still further embodiment, the present disclosure relates to a method of diagnosing the glomerular filtration rate of a mammal, preferably the glomerular filtration rate (GFR), wherein at least one compound of formula (I) or a diagnostic formulation comprising at last a compound of formula (I) is administered to a mammal and the fluorescent signal emitted from the dye of compound of formula (I) is detected and measured.
[0101] Preferably, the at least one compound of formula (I) or the diagnostic formulation comprising at least one compound of formula (I) is administered to the mammal via a parenteral route.
[0102] The diagnostic method herein disclosed is non-invasive, because the detection and measurement of the fluorescence emitted from the at least one compound of formula (I) are realized by detecting and measuring the fluorescent emission emerging from the skin of the mammal in response to excitation with a red light or near infrared light source, preferably by means of a sensor device placed onto the mammal skin. The method is accomplished in a clinically relevant period of time. That is, that period of time is such to allow the absorption of the compound of formula (I) in the blood of the mammal and the following secretion by the kidney system.
[0103] In a further embodiment, a compound of formula (I) can be used for screening pharmaceutical compounds (test agents) suitable for treatment of chronic kidney diseases.
[0104] The screening method comprises:
[0105] i) administering to an animal model of chronic kidney diseases the test agent and at least one fluorescent compound of formula (I), wherein the fluorescent compound is administered subsequently to test agent;
[0106] ii) measuring the glomerular filtration rate by detecting and measuring the fluorescence emission of the at least one fluorescent compound, wherein the detection and the measurement of the fluorescence comprises the detection and the measurement of the fluorescent emission emerging from the skin of the animal model in response to excitation with a red light or near infrared light source;
[0107] iii) selecting the test agent that increases glomerular filtration rate.
[0108] Mammalian models of chronic kidney diseases in, for example, mice, rats, guinea pigs, cats, dogs, sheep, goats, pigs, cows, horses, and primates, may be created by causing an appropriate direct or indirect injury to the kidney tissue of the animal. Animal models of acute kidney failure may, for example, be created by inducing in the animal the conditions or diseases such as acute interstitial nephritis or acute tubular necrosis, for example by the controlled administration of nephrotoxic agents (e.g., antibiotics, aminoglycoside drugs, heavy metals).
[0109] Other mammalian models of chronic kidney disease are disclosed in Vukicevic, et al. (1987), J. Bone Mineral Res. 2:533; and EP-B-0 914 146; animal models have been described in detail in a handbook Experimental and genetic rat models of chronic renal failure , Gretz, N.; Strauch, M.; Karger (Basel and New York); 1993; pp 343; (ISBN 3805554990). Rat models of autosomal dominant polycystic kidney disease have been described in Gretz N, Kränzlin B, Pey R, Schieren G, Bach J, Obermüller N, Ceccherini I, Klöting I, Rohmeiss P, Bachmann S, Hafner M. Nephrol Dial Transplant. 1996; 11 Suppl 6:46-51. Review; murine models of polycystic kidney disease have been described in Schieren G, Pey R, Bach J, Hafner M, Gretz N. Nephrol Dial Transplant . 1996; 11 Suppl 6:38-45. Review.
[0110] The following examples are intended to illustrate particular aspects of the present invention and should not be construed as limiting the scope thereof as defined by the claims.
[0111] The following examples provide a detailed description of the synthesis of the tricarbocyanine named 2-((E)-2-((E)-2-((4-(2-carboxyethyl)phenyl)amino)-3-((E)-2-(3,3-dimethyl-5-sulfonate-1-(3-trimethylammonium)propyl)indolin-2-ylidene)ethylidene)cyclohex-1-en-1-yl)vinyl)-3,3-dimethyl-1-(3-(trimethylammonium)propyl)-3H-indol-1-ium-5-sulfonate bromide (named ABZWCY), its conjugation to a cyclodextrin molecule and its use in a diagnostic method for determining GFR in a rat.
[0112] A fluorescent tricarbocyanine dye ABZWCY (4) was synthesized and linked to HβCD, according to Example 1 and Reaction Schemes 1-4.
[0113] The resulting ABZWCY-HβCD conjugate exhibited excellent water solubility with concentrations reaching more than 100 mg/mL. In addition it showed a low plasma protein binding (PPB), i.e. less than 10%, which is a lower value than 125 I-iothalamate, one of the golden standard agent for the GFR measurement [Levey, A. S. et al. J. Am. Soc. Nephrol . 1993 4(5), 1159-1177].
[0114] The noninvasive real-time monitoring of plasma clearance resulted in a half-life of approximately 17±2 min. Moreover, the tricarbocyanine-cyclodextrin marker did not exhibit significant differences in plasma clearance half time in the absence and presence of a compound able to inhibit tubular secretion. This means that kidney tubular secretion is not a significant elimination pathway for these markers in a mammal. The present marker was exclusively cleared by the kidneys, with no appreciable nonspecific background signal in all the tissues and organs and only fluorescence signal remaining in the bladder 2 h post injection. In conclusion, such a fluorescent compound is highly suitable as exogenous fluorescent tracer for monitoring GFR.
Example 1
Preparation of ABZWCY-HβCD
a) Preparation of 2,3,3-Trimethyl-1-[3-(trimethylammonium)propyl]-3H-indolinium sulfonate bromide (1)
[0115] The reaction was carried out according to Scheme 1.
[0000]
[0116] A mixture of 2,3,3-trimethyl-3H-indole-5-sulfonic acid (1.54 g, 6.5 mmol; (prepared according to Mujumdar et al., Bioconjugate Chemistry (1993), 4/2, 106) and (3-bromopropyl)trimethyl ammonium bromide (2.51 g, 9.5 mmol) in 1,2-dichlorobenzene (16 mL) was heated at 130° C. for 72 hours under argon flow. The reaction mixture was cooled to room temperature and the solvent was decanted. The crude product was washed with CH 2 Cl 2 , dissolved in acetone and reprecipitated into a large volume of ethyl acetate to afford a solid 1, which was used in the next step without further purification.
b) Preparation of 2-((E)-2-((E)-2-chloro-3-((E)-2-(3,3′-dimethyl-5-sulfonate-1-(3-(trimethylammonium)propyl)-indo-lin-2-ylidene)cyclohex-1-enyl)-3,3-dimethyl-1-(3-(trimethylammonium)-propyl)-3H-indolium-5-sulfonate bromide (3)
[0117] The reaction was carried out according to Scheme 2.
[0000]
[0118] A mixture of bromide salt 1 (0.5 g, 1.48 mmol), Vilsmeier-Haack reagent 2 (0.265 g, 0.73 mmol; prepared according to Makin S. M.; Boiko, L. I.; Shavrigina, O. A. Zh. Org. Khim . 1977, 13, 1189) and anhydrous sodium acetate (0.246 g, 3 mmol) was refluxed in 10 ml of absolute ethanol for 6 h under argon flow. The reaction mixture was cooled to room temperature, and then concentrated under reduced pressure to yield a brown-green residue. The crude product was washed with dichloromethane and the residue was suspended in methanol/dichloromethane (1/4, 100 mL), filtered and dried in vacuo to yield a golden-green solid (3) 505 mg, yield=84.9%.
[0119] 1 HNMR (400 MHz, DMSO-d 6 ) δ 1.72 (s, 12H), 1.88 (m, 2H), 2.18 (m, 4H), 2.76 (m, 4H), 3.08 (s, 18H), 3.49 (m, 4H), 4.18 (m, 4H) m 6.36 (d), 7.45 (d) 7.85 (s, 2H), 8.31 (d, 2H). Absorption max (MeOH) 777 nm (methanol). Emission max (MeOH): 810 nm.
c) Preparation of 2-((E)-2-((E)-2-((4-(2-carboxyethyl)phenyl)amino)-3-((E)-2-(3,3-dimethyl-5-sulfonate-1-(3-trimethylammonium)propyl)indolin-2-ylidene)ethylidene)-cyclohex-1-en-1-yl)vinyl)-3,3-dimethyl-1-(3-(trimethylammonium)propyl)-3H-indol-1-ium-5-sulfonate bromide (ABZWCY, 4)
[0120] The reaction was carried out according to Scheme 3.
[0000]
[0121] A mixture of 3 (220 mg, 0.27 mmol) and 3-(4-aminophenyl)propanoic acid (178 mg, 1.08 mmol) in DMSO was heated at 65° C. overnight. The reaction mixture was cooled to room temperature and precipitated in dichloromethane. The crude product was purified by RP C18 chromatography to yield a blue solid 130 mg.
[0122] FW for C 51 H 68 N 5 O 8 S 2 Br: 1023.15; exact mass of cation 942.45.
d) Preparation of ABZWCY-HβCD (5)
[0123] Materials:
[0124] 2-hydroxypropyl-β-cyclodextrin (HβCD) was purchased from Sigma-Aldrich (Product No. H-107 of molecular formula (C 6 H 9 O 5 ) 7 (C 3 H 7 O) 4.5 ; average molecular weight; 1396 (anhyd.) water solubility 45 g/100 mL).
[0125] The reaction was carried out according to Scheme 4.
[0000]
[0126] A mixture of dye 4 (40 mg), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (20 mg), 4-dimethylaminopyridine (10 mg) and (2-hydroxypropyl)-β-cyclodextrin (550 mg) and DMSO (6 mL) was stirred under room temperature for 12 hours. The reaction mixture was then precipitated in dichloromethane. The obtained crude product was further purified by Sephadex G-10 gel filtration to yield blue solid (5), 350 mg.
[0127] MS (ESI) m/z=cluster of peaks between 2200-2470, average 2335; estimated average m/z for ABZWCY-HβCD: 2338 (943 (ABZWCY)+1396 (HβCD, as indicated by producer).
[0128] Absorption max=700 nm; Emission max=791 nm. Absorption and emission spectra are shown in FIGS. 3 and 4 .
[0129] Water solubility >100 mg/mL.
Example 2
Plasma protein binding (PPB) for ABZWCY-HβCD
[0130] Stock Solution Preparation.
[0131] An ABZWCY-HβCD/plasma stock solution was prepared by incubation of 500 μg/ml ABZWCY-HβCD (in PBS solution) with rat plasma protein at 37° C. for 1 hour.
[0132] Equilibrium Dialysis.
[0133] Plasma protein binding measurements were performed by equilibrium dialysis technique using a two-chamber dialysis set up. 400 μl of the stock solution (see above) was placed into one side of two-chamber dialysis apparatus, another side was filled with 400 μl distilled water, and the marker-protein solution was dialyzed. At 18 and 36 hours, the concentration of the free marker in the water side and plasma side of the cell was determined by absorption spectroscopy and calculated on the basis of Beer's law.
[0134] Calculations:
[0000] PPB %= C marker bound to plasma /C marker dye ×100
[0000] PPB %=( C P −C W )/( C P +C W )×100
[0000] PPB %=( A P −A W )/( A P +A W )×100
[0000] wherein
A P represents the absorbance in the plasma side of the cell after dialysis,
A W represents the absorbance in water side of the cell after dialysis.
[0135] PPB % was calculated to be 8.4% (average of 3 experiments).
Example 3
Plasma Clearance Half-Life for ABZWCY-HβCD
[0136] Plasma clearance half-life was analysed in combination with an electronic near infrared device for the transcutaneous fluorescence detection in rat models.
[0137] Animal:
[0138] female Sprague-Dawley rats.
[0139] Substance:
[0140] ABZWCY-HβCD Dosage:
[0141] ABZWCY-HβCD: 5 mg/100 g body weight Electronic Near Infrared Device for Transcutaneous Fluorescence Detection.
[0142] This device (sensor plaster), described in detail in US2011230739A1, “Transcutaneous Organ Function Measurement”, consists of (a) a plaster which can be stuck onto the skin surface; (b) a near infrared emitting diode; (c) a radiation detector. The adhesive surface of the sensor plaster laterally encloses the detector to prevent ambient light from being able to pass to the detector. The near infrared radiation (peak at about 680 nm) is partially absorbed by the marker; the response radiation is detected at about 800 nm. The sensor plaster is electrically connected to an electronic device comprising a microcontroller and a battery, for data acquisition and their RFID transmission to an external computer ( FIGS. 5 and 6 ).
[0143] Procedure.
[0144] SD rats are anesthetized with isoflurane, shaved on the back, then the electronic near infrared device is attached. ABZWCY-HβCD is administered (5 mg/100 g, body weight) via intravenous injection. Transcutaneous measurement usually last 2 h.
[0145] Stock Solution Preparation.
[0146] An ABZWCY-HβCD/plasma stock solution is prepared by incubation of 500 μg/ml ABZWCY-HβCD (in PBS solution) with rat plasma protein at 37° C. for 1 hour.
[0147] Plasma clearance kinetics for ABZWCY-HβCD is shown in FIG. 6 : (a) 1 exponential fitting (1e); (b) 3 exponential fitting (3e).
Example 4
Plasma Clearance Half-Life for ABZWCY-HβCD in the Presence of Probenecid
[0148] In order to determine whether kidney tubular secretion had any effect on the clearance of these markers, separate pharmacokinetic experiments involving blockage of tubular secretion using Probenecid [p-(dipropyl-sulfamoyl)benzoic acid] were carried out.
[0149] The experimental protocol was approved and conducted in accordance with the German Ministry of Health and according to the The National Animal Protection Guidelines.
[0150] Animal:
[0151] female Sprague-Dawley rats.
[0152] Substances:
[0153] ABZWCY-HβCD.
[0154] Dosage:
[0155] ABZWCY-HβCD: 5 mg/100 g body weight; Probenecid: 50 mg/kg body weight.
[0156] Electronic Near Infrared Device for Transcutaneous Fluorescence Detection.
[0157] As described above.
[0158] Procedure:
[0159] SD rats are anesthetized with isoflurane, shaved on the back, then the electronic near infrared detector device is attached. ABZWCY-HβCD is administered (5 mg/100 g, body weight) via intravenous injection. Rats are previously treated (30 min. before measurement) with Probenecid (50 mg/kg body weight in 0.9% Saline, intraperitoneally). The transcutaneous measurement lasts approximately 2 h.
[0160] Plasma clearance kinetics for ABZWCY-HβCD in the presence of Probenecid is shown in FIG. 7 : (a) 1 exponential fitting (1e); (b) 3 exponential fitting (3e).
[0161] Plasma clearance half-life values measured in Examples 3 and 4 are summarized in Table 2.
[0000]
TABLE 2
Clearance half-life (minutes)
Mean ± SD
Conjugate
1-parameter fitting
3-parameter fitting
ABZWCY-HβCD (n = 6)
17.7 ± 3.3
16.9 ± 4.7
ABZWCY-HβCD +
18.5 ± 6.6
15.9 ± 5.5
Probenecid (n = 5) | The present invention relates to novel tricarbocyanine-cyclodextrin(s) conjugates useful as markers in the diagnosis of kidney diseases, a diagnostic composition comprising said conjugates, their use and their production. | 2 |
FIELD OF THE INVENTION
[0001] Embodiments of the invention relate to diabetes management systems and, more particularly, to securing a fluid reservoir within a portable infusion device.
BACKGROUND OF THE INVENTION
[0002] Infusion devices and glucose monitoring systems are relatively well known in the medical arts, particularly for use monitoring blood glucose levels and delivering or dispensing a prescribed medication to a user. In many cases, the user suffers from diabetes—a disease in which the body does not produce or properly use insulin. Approximately 13 million people in the United States have been diagnosed with some form of diabetes. Type 1 diabetes results from the body's failure to produce insulin. Type 2 diabetes results from insulin resistance in which the body fails to properly use insulin. In order to effectively manage and/or control the disease, diabetics must closely monitor and manage their blood glucose levels through exercise, diet and medications in addition to supplying their body with appropriate amounts of insulin based on daily routines. In particular, both Type 1 and Type 2 diabetics rely on insulin delivery and blood glucose monitoring systems to control diabetes.
[0003] External infusion devices have been used to deliver medication to a patient as generally described in U.S. Pat. Nos. 4,562,751; 4,678,408; 4,685,903; 6,554,798, and 6,551,276 which are specifically incorporated by reference herein. In recent years, continuous glucose monitoring systems have been developed utilizing the latest sensor technologies incorporating both implantable and external sensors, as generally described in U.S. Pat. No. 5,391,250 entitled “Method of Fabricating Thin Film Sensors”, U.S. Pat. No. 6,484,046 entitled “Electrochemical Analyte Sensor,” and U.S. Pat. Nos. 5,390,671, 5,568,806 and 5,586,553, entitled “Transcutaneous Sensor Insertion Set,” all of which are specifically incorporated by reference herein. Newer systems deliver the preciseness of finger stick measurements coupled with the convenience of not having to repeatedly prick the skin to obtain glucose measurements. These newer systems provide the equivalent of over 200 finger stick readings per day. Additionally, continuous glucose monitoring systems allow physicians and patients to monitor blood glucose trends of their body and suggest and deliver insulin based on each patient's particular needs. Accordingly, physicians and medical device companies are always searching for more convenient ways to keep diabetic patients aware of their blood glucose levels throughout the day.
[0004] Diabetic patients utilizing infusion therapy and continuous glucose monitoring systems depend on extremely precise and accurate systems to assure appropriate blood glucose readings and insulin delivery amounts. Furthermore, as younger diabetic patients and diabetic patients with active lifestyles embrace infusion therapy it is imperative to ensure the infusion devices and sensors are robust and reliable.
SUMMARY OF THE DISCLOSURE
[0005] In one embodiment a fluid infusion system is disclosed. The fluid infusion system includes a pump housing that has a reservoir cavity and is designed to be pocketable. The reservoir cavity has a rim and helical coupling features formed on an interior face of the reservoir cavity. The fluid infusion system further has a reservoir that is removable from the reservoir cavity and the reservoir also has an open end. A removable cap coupled to the pump housing is also included in the fluid infusion system. The cap has corresponding coupling features, an exterior surface and a tab. The corresponding coupling features are defined to couple the cap to the pump housing while the tab is defined as a ridge that extends away from the exterior surface. The tab further has a port to accommodate fluid flow from the reservoir where the port defines an axis of rotation such that torque applied to the tab about the axis of rotation disengages the coupling between the cap and the pump housing. Further included in the infusion system is a guard that is removably coupled to the pump housing. The guard has a slot defined to immobilize rotation of the tab about the axis of rotation.
[0006] In another embodiment a system to retain a fluid medication reservoir within a medication pump housing is disclosed. The system includes a pump housing that is pocketable having a reservoir cavity that has a rim and helical coupling features. The helical coupling features formed on an interior face of the reservoir cavity and having a dimple formed on the rim. The system further includes a reservoir that has an open end and is removable from the reservoir cavity. A cap that is removably coupled to the pump housing is also included in the system. The cap has corresponding coupling features, an exterior surface, and a tab. The corresponding coupling features are defined to couple the cap to the pump housing, and include a snap defined on an edge of the cap that removably interfaces with the dimple on the pump housing. The tab is defined as a ridge that extends away from the exterior surface and the tab has a port to accommodate fluid flow from the reservoir. The port through the tab defines an axis of rotation such that torque applied to the tab about the axis of rotation disengages the coupling between the cap and the pump housing. The system further includes a guard that is removably coupled to the pump housing. The guard has a slot that is defined to immobilize rotation of the tab about the axis of rotation. Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, various features of embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] A detailed description of embodiments of the invention will be made with reference to the accompanying drawings, where like numerals designate corresponding parts or cross-sections in the several figures.
[0008] FIG. 1 is an exemplary illustration of a fluid infusion system that includes a pump, an insertion set and a sensor, in accordance with embodiments of the present invention.
[0009] FIGS. 2A and 2B are exemplary perspective views of a portion of the pump housing, with guard installed and removed respectively, in accordance with embodiments of the present invention.
[0010] FIG. 2C is a top view illustration of a portion of the pump housing with a guard installed over the cap, in accordance with embodiments of the present invention.
[0011] FIG. 3 is a perspective view of the pump illustrating features on the pump housing that are engaged by the guard, in accordance with embodiments of the present invention.
[0012] FIGS. 4A and 4B are close-up perspective views illustrating features of the pump housing and the guard, in accordance with embodiments of the present invention.
[0013] FIGS. 5A-5D are additional views of the pump housing and the guard, in accordance with embodiments of the present invention.
[0014] FIGS. 6A and 6B are exemplary perspective illustration showing features that prevent the guard from being installed onto the pump in a reverse orientation, in accordance with embodiments of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] FIG. 1 is an exemplary illustration of a fluid infusion system 10 that includes a pump 100 , an insertion set 106 and a sensor 112 , in accordance with embodiments of the present invention. Mechanical, electrical and software elements of the pump 100 are contained within a pump housing 110 . The pump includes a reservoir 104 that is removable from a reservoir cavity within the pump housing 110 . The reservoir 104 may be filled with a fluid that can be dispensed from the pump 100 to the insertion set 106 via tubing 108 . A cap 102 interfaces with both the pump 100 and the reservoir 104 to connect the tubing 108 with the reservoir 104 .
[0016] The sensor 112 is an assembly that includes a subcutaneous sensor, a power supply and a radio to transmit data acquired by the sensor to the pump 100 . The pump 100 is configured and programmed to be in wireless communication with the sensor 112 . For additional information regarding the pump 100 see U.S. Pat. No. 6,554,798 by Mann et al., for additional information regarding the connection between the reservoir 104 and the insertion set 106 see U.S. Pat. No. 6,585,695 by Adair et al., furthermore, for additional information regarding the sensor 112 see U.S. Pat. No. 5,568,806 by Cheney et al., U.S. Pat. No. 6,484,045 by Holker et al., and U.S. Pat. No. 7,003,336 by Holker et al., all of which are incorporated by reference herein. For additional information regarding the use the sensor 112 with a monitor or pump, please see U.S. Pat. No. 6,809,653 by Mann et al. which is incorporated by reference herein.
[0017] FIGS. 2A and 2B are exemplary perspective views of a portion of the pump housing 110 , with guard 200 installed and removed respectively, in accordance with embodiments of the present invention. The guard 200 interfaces with features on the pump housing 110 and the cap 102 . The cap 102 has an exterior surface 206 and a tab 202 . In one embodiment the tab 202 is defined as a ridge that extends away from the exterior surface 206 . The tab 202 includes a port 204 that can accommodate tubing (not shown). A user can grasp the tab 202 in order to apply a torque to the cap 102 in order to remove the cap 102 and attached reservoir from the pump housing 110 . The embodiment illustrated in FIGS. 2A and 2B should not be construed as limiting.
[0018] As will be described in more detail in the description of FIG. 3 , the pump housing 110 has a rim 208 that includes and enables features that interface with the guard 200 . In one embodiment, the rim 208 of the pump housing 110 is formed from a separate part that is mated and permanently affixed to the pump housing 110 . Methods of permanently affixing the rim 208 to the pump housing 208 include, but are not limited to the use of insert molding, ultrasonic welding, adhesives or the combination thereof. In other embodiments, the rim 208 and associated features are created during the forming of a one-piece pump housing. Regardless of the whether the rim 208 is formed or installed, the pump housing 110 includes a rim 208 that facilitates the installation and retention of the guard 200 .
[0019] FIG. 2C is a top view illustration of a portion of the pump housing 110 with a guard 200 installed over the cap 102 , in accordance with one embodiment of the present invention. As illustrated, the guard 200 includes arms 210 a and 210 b that are connected. Defined between the arms 210 a and 210 b is a slot 212 . As illustrated, when the cap 102 in installed on the pump housing 110 and a guard 200 in placed over the cap 102 , the slot 212 captures the tab 202 to prevent rotation of the tab 202 .
[0020] FIG. 3 is a perspective view of the pump 100 illustrating features on the pump housing 110 that are engaged by the guard (not shown), in accordance with embodiments of the present invention. As illustrated, features on the pump housing 110 that are engaged by the guard include, but are not limited to, a rib 300 , a nub 302 a , and detents 304 a and 304 d . In one embodiment the nub 302 a is formed entirely on the rim 208 . Conversely, the rib 300 can be formed when the rim 208 is permanently affixed to the case housing 110 . Likewise, detents 304 a and 304 d can also be formed when the rim 208 is affixed to the pump housing 110 . Additional features on the pump housing 110 will be discussed below when the various views of the pump housing 110 reveal the different features.
[0021] FIGS. 4A and 4B are close-up perspective views illustrating features of the pump housing 110 and the guard 200 , in accordance with embodiments of the present invention. Arms 210 a and 210 b terminate away from the joint with snaps 400 a (not shown) and 400 b respectively. Each snap 400 a and 400 b have a corresponding detent 304 a and 304 b (not shown) formed on the case housing 110 . Additionally, snap 400 d is formed on arm 210 a near the joint between arms 210 a and 210 b . Similarly, though not shown in FIGS. 4A and 4B , snap 400 c is formed on arm 210 b . As previously discussed, the detents 304 a and 304 b can be formed during the fabrication of the case housing 110 or when the rim 208 is affixed to the case housing. In the exemplary embodiment shown in FIG. 4B the snap 400 d has a tapered face 402 . While not shown, a corresponding snap 400 c located on arm 210 b can also include a tapered face. The use of the tapered face 402 facilitates the installation of the guard 200 onto the case housing 110 . Specifically, the tapered face 402 enables the use of a lower amount of force necessary to pass snap 400 d over the rim 208 in order to engage an corresponding detent.
[0022] FIGS. 5A-5D are additional views of the pump housing 110 and the guard 200 , in accordance with embodiments of the present invention. FIG. 5A is a profile view of the arm 210 a and illustrates how detent 304 a is engaged by a snap on the terminated arm 210 a Likewise, snap 400 c is shown engaged in detent 306 a . Also visible in FIG. 5A is the profile contour of face 500 . The contour of face 500 in conjunction with the placement of snaps 400 c enables the repeated removal of guard 200 from the pump housing 110 . The face 500 allows user to apply an upward force that can disengage snap 400 c and 400 d (not shown) from detent 306 a and 306 b (not shown).
[0023] FIGS. 5B and 5C are exemplary illustrations where the guard 200 has been made translucent in order to show how the guard 200 interfaces with the pump housing 110 , in accordance with embodiments of the present invention. As FIG. 5B illustrates the arm 210 b side of the pump housing 110 , snap 400 c and detent 306 b are visible. FIGS. 5B and 5C also illustrate how the guard 200 includes a recess 502 that interfaces with the rib 300 of the pump housing 110 . The recess 502 and the rib 300 work in conjunction with the slot 212 ( FIG. 2C ) to allow the guard to resist torque applied to the tab 202 . The use of both the slot and the rib 300 to prevent rotation of the tab 202 is merely one embodiment. In other embodiments only the slot formed between arms 210 a and 210 b may be used to counteract rotation of the tab. Similarly, in another embodiment, only the rib 300 and recess 502 may be used to lock the tab 202 by preventing rotation Likewise, additional features can be used to immobilize rotation of the tab in furtherance of either the slot and the rib.
[0024] FIGS. 5C and 5D provide an exemplary illustration of the removal of the guard 200 from the pump housing 110 , in accordance with embodiments of the present invention. In one embodiment to avoid inadvertent removal, the guard 200 is securely attached to the pump housing 110 and requires two steps to remove the guard 200 . To initiate removal of the guard 200 , a force F 1 is applied to both arms 210 a and 210 b , as illustrated in FIGS. 5C and 5D . Application of force F 1 causes the arms 210 a and 210 be spread. Force F 1 further pushes the guard 200 toward the rib 300 . FIG. 5D illustrates the second step to remove the guard 200 , the application of force F 2 on face 500 ( FIG. 5A ). The application of force F 1 can help disengage snap 400 c ( FIG. 5B ) and snap 400 d ( FIG. 4A ) thus allowing force F 2 to remove the guard 200 from the pump housing 110 . As the guard 200 can be installed to prevent children from accidentally removing the cap 102 , a two step method (the application of F 1 and F 2 ) can make it more difficult for children to remove the guard 200 . If F 2 is not applied after application of F 1 the geometry of the legs is such that the Guard reseats itself.
[0025] While it may be beneficial in some instances to have a two step removal process, it should not be construed as required. In other embodiments, a one step removal process may be used while in other embodiments three or more steps may be desired to ensure the guard is difficult to remove. Additionally, for two step removal, the steps outline above should not be considered restrictive as other embodiments of the guard 200 may use a different combination of forces other than F 1 and F 2 .
[0026] FIG. 5C further provides an illustration of additional retention features on both the pump housing 110 and the cap 102 , in accordance with embodiments of the present invention. The cap 200 includes snaps 504 a and 504 b that are formed on an outer edge of the cap 200 . Included on an interior face of the rim 208 are dimples 506 a and 506 b that correspond to the snaps 504 a and 504 b . While FIG. 5C illustrates the use of two snaps 504 a and 504 b , other embodiments can use fewer or more snaps. Furthermore, while the snaps 504 a and 504 b are illustrated substantially opposite of each other, other configurations could be used to incorporate fewer or greater number of snaps. For example, snap configurations could include, but are not limited to three equally spaced snaps, four equally spaced snaps, and even a single snap. Still other snap configuration could include snaps that are not equally spaced. In embodiments were the cap 102 utilizes fewer or more snaps that illustrated in FIG. 5C , the rim would have a corresponding number of dimples to accommodate the snaps on the cap.
[0027] FIGS. 6A and 6B are exemplary perspective illustration showing features that prevent the guard 200 from being installed onto the pump 100 in a reverse orientation, in accordance with embodiments of the present invention. In FIG. 6A the guard 200 is shown in a reverse orientation such that the rib 300 is not aligned with the recess 502 ( FIG. 5C ) of the guard 200 . Nubs 302 a and 302 b are included on the rim 208 to prevent installation of the guard 200 in this orientation. The nubs 302 a and 302 b are designed to interfere with the guard 200 and prevent the guard 200 from snapping onto the pump housing 110 . In other embodiments, the nubs 302 a and 302 b are replaced with a rib that extends the surface of the rim 208 to a height equivalent to the nubs 302 a and 302 b . FIG. 6B is an exemplary illustration showing how the termination of arms 210 a and 210 b create an interference 600 with the pump housing 110 in order to prevent the guard 200 from being installed in the reverse orientation.
[0028] While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.
[0029] The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. | The fluid infusion system is disclosed that includes a pump housing that has a reservoir cavity and is designed to be pocketable. The reservoir cavity has a rim and helical coupling features formed on an interior face of the reservoir cavity. The fluid infusion system further has a reservoir that is removable from the reservoir cavity and the reservoir also has an open end. A removable cap coupled to the pump housing is also included in the fluid infusion system. The cap has corresponding coupling features, an exterior surface and a tab. The corresponding coupling features are defined to couple the cap to the pump housing while the tab is defined as a ridge that extends away from the exterior surface. The tab further has a port to accommodate fluid flow from the reservoir where the port defines an axis of rotation such that torque applied to the tab about the axis of rotation disengages the coupling between the cap and the pump housing. Further included in the infusion system is a guard that is removably coupled to the pump housing. The guard has a slot defined to immobilize rotation of the tab about the axis of rotation. | 0 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Provisional Application No. 61/492,714, filed Jun. 2, 2011.
TECHNICAL FIELD
[0002] The current application is directed to fuel systems for fueling vehicles and, in particular, to a single-spout, dual-channel fueling nozzle that extracts spent fuel from a vehicle and introduces fresh fuel into the vehicle.
BACKGROUND
[0003] The fueling of a vehicle that uses recyclable fuels involves the input of fresh fuel, in certain cases hydrogenated fuel from which hydrogen can be extracted by internal vehicle components for powering the vehicle, while at the same time removing used or spent liquid fuel, in certain cases relatively dehydrogenated fuel. There have been proposed a number of different technologies that feature a nozzle with two different parallel spouts mounted side by side on a single handle. The use of this type of nozzle is quite cumbersome, since each of the two spouts mate to a different, separate filler neck. Fluid flows out of one spout into the filler neck of the fresh fuel tank in the vehicle. Fluid from the vehicle's used fuel tank is pumped out through the second filler neck. There are still other recyclable-fuel nozzles that mount to a bayonet-type filler neck. These nozzles are useable, but are not publically accepted because operation of this type of recyclable-fuel nozzle is not intuitive to the average user.
SUMMARY
[0004] One example of the fuel systems to which the current application is directed comprises a single-spout, dual-channel recyclable-fuel fueling nozzle that extracts spent fuel from a vehicle and introduces fresh fuel into the vehicle via a single filler neck. Liquids move in two different directions within two separate channels of the dual-channel recyclable-fuel fueling nozzle to and from two different reservoirs within the vehicle, including a fresh-fuel reservoir and a spent-fuel reservoir.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 illustrates a fueling nozzle and filler neck, not mated, of a single-spout, dual-channel recyclable-fuel fueling nozzle.
[0006] FIG. 2 illustrates a nozzle partially inserted coming in contact with rubber outer seal of a single-spout, dual-channel recyclable-fuel fueling nozzle.
[0007] FIG. 3 illustrates a nozzle fully inserted opening a sliding gate valve of a recyclable-fuel filler neck.
[0008] FIG. 4 illustrates a gate valve closed showing spent fuel chamber with wrong fuel of a recyclable-fuel filler neck.
[0009] FIG. 5 shows a gate valve closed showing fresh fuel volume and path of a recyclable-fuel filler neck.
[0010] FIG. 6 shows fresh-fuel and spent-fuel flow paths within a mated nozzle and filler neck.
DETAILED DESCRIPTION
Description
[0011] The current application is directed to a single-spout, dual-channel recyclable-fuel fueling nozzle and complementary vehicle filler neck for transferring fuels to and from a vehicle. Fueling is accomplished such that, as a quantity of fuel is inserted into the on-board fresh-fuel tank, a like quantity is extracted from a second on-board spent-fuel tank.
[0012] FIG. 1 illustrates a fueling nozzle and filler neck, not mated, of a single-spout, dual-channel recyclable-fuel fueling nozzle. The nozzle itself is coaxial in design, where fresh fuel flows through the center channel and out of the nozzle to the vehicle tank. The two fluids flow in opposite directions within the nozzle. Spent fuel flows into the outer channel of the nozzle from the spent-fuel tank within the vehicle. The volumes of the two channels are approximately equal even though the geometries may not be identical or even similar. This assures that the flow rate through the nozzle in both directions is uniform. The fluid flow is synchronized, such that if the difference between the quantity of the flow into the nozzle from the vehicle and the quantity of the flow out of the nozzle to the vehicle is not below a small threshold value, the system shuts off. This no-flow condition indicates the fuel tank in the vehicle is full and stops the filling process. This configuration of outer channel as the spent or used fuel allows for the sealing of the outer diameter of the nozzle to return any fuel that leaks to the bulk spent-fuel tank.
Operation
[0013] The filler cap of the filler neck is first removed. The figures have the filler cap removed to show clarity of the overall design. The filler nozzle is now inserted into the filler neck until is stops. This is similar to what we do today when filling a vehicle with gasoline. The nozzle trigger is squeezed and the filling begins.
[0000] Inserting of the Nozzle into Filler Neck
[0014] As the nozzle is being inserted into the neck an outer rubber seal comes in contact with the outer diameter of the spout portion of the nozzle. FIG. 2 illustrates a nozzle partially inserted coming in contact with rubber outer seal of a single-spout, dual-channel recyclable-fuel fueling nozzle. As the spout is further inserted into the filler neck the far end of the spout pushes against a spring loaded sliding gate valve opening the fresh fuel chamber. FIG. 3 illustrates a nozzle fully inserted opening a sliding gate valve of a recyclable-fuel filler neck. This far end of the nozzle enters the fresh fuel chamber. The length of the spout is longer than a conventional spout so if a conventional spout is inserted it will never contact the gate valve to open it. At this point the fresh fuel chamber and the spent fuel chambers are now aligned with the openings of the nozzle and fueling can continue.
Fluid Flow
[0015] Communications with a host are now established. If the funding account is approved fueling can begin. Fuel flows out of the center channel of the nozzle into the fresh fuel chamber of the filler neck. FIG. 6 shows fresh-fuel and spent-fuel flow paths within a mated nozzle and filler neck. From the filler neck, fresh fuel flows into the fresh fuel tank within the vehicle. Spent fuel is pumped from the spent or used fuel tank into the spent fuel chamber in the neck and into the outer channel of the nozzle. The fresh fuel tank and spent fuel tank are contained within a single rigid volume. These can be two bladders within the outer tank case. Fuel is pumped into a fresh-fuel bladder though an opening and fills the fresh-fuel bladder. As the fresh-fuel bladder fills, the fresh-fuel bladder applies pressure to the spent-fuel bladder, forcing spent fuel out through an opening and into the filler neck.
RFID
[0016] The flow rate, fuel quantity, and identification of the vehicle are captured using an RFID tag (Radio Frequency Identification). The signals sent between the nozzle and the pump are encrypted so that any eavesdropping electronics are unable to utilize the data for illegal purposes. The RFID system can also be used as a credit card. The car pulls up to the pump. The driver inserts the nozzle into the filler neck. At that point the RFID tag and pump establish a secure communication link. Communications between the pump and a central card processor server are then established.
[0017] To secure the RF communications link to the central server, when a credit card account is first set up, a seed number is established based on the time for that account. The seed number infrequently changes, but a security number produced from the seed number by an algorithm does frequently change. A new security number is generated once every minute, in one example. This security number is generated by both the credit card server and the RFID tag. Since the security number is based on both a time and the seed number, the probability of randomly generating that the security number is quite low. When a transaction is about to begin, the security number is sent from the RFID tag to the central credit card processor to identify the RFID tag and compare the security number obtained from the RFID tag with a corresponding security number associated with an account. If the two security numbers are identical, then the transaction can be approved. This technique prevents a nearby electronic RF recording device from using the data presented from the RFID since the security number will have changed within the next minute. Electronics within the nozzle are intrinsically safe and meet local, state, and federal codes.
Prevention of Wrong Fuel
[0018] The filler neck is designed so that the lower chamber is for the input of fresh fuel while the upper chamber is for spent fuel. FIG. 4 illustrates a gate valve closed showing spent fuel chamber with wrong fuel of a recyclable-fuel filler neck. If the filling nozzle from a standard gasoline or diesel is inserted into the filler body, the upper chamber of the neck will fill up. This action of filling activates the automatic shut off of the gasoline or diesel nozzle by covering the venturi shutoff port typically located at the far end of the nozzle. This prevents an incorrect fuel from entering the fresh fuel chamber of the filler body. The automatic shut off feature using a venturi shutoff port is found on all nozzles currently being used. When a correct recyclable-fuel nozzle is inserted into the body of the filler neck while there is fluid in the upper chamber and actuated, the recyclable-fuel nozzle removes any fluid captured in the that chamber before pumping fresh fuel into the vehicle. When the correct recyclable-fuel is inserted into the filler neck, the upper chamber is first pumped out back to a temporary holding tank. The temporary holding tank can be analyzed for contaminants and other materials before contents of the temporary holding tank are sent to a final holding tank. In this way, if gasoline or diesel has inadvertently entered the system, it can be sent to a disposal tank rather than a recycle tank.
Look and Feel of the Nozzle
[0019] The single-spout, dual-channel recyclable-fuel fueling nozzle looks like today's existing nozzles with which most individuals have had the experience of filling a vehicle. The single-spout, dual-channel recyclable-fuel fueling nozzle has the same single spout with a single squeeze grip handle. Operation and look and feel of the single-spout, dual-channel recyclable-fuel fueling nozzle is similar to that of a standard nozzle one sees today at any refueling station. The outer diameter of the single-spout, dual-channel recyclable-fuel fueling nozzle is larger than a fueling nozzle that one finds today, to insure the nozzle is not accidentally inserted into a vehicle with a regular diesel or gasoline tank. In one example, the nozzle and filler neck are keyed so that if the nozzle is inserted into a non-keyed filler neck, the nozzle prevents flow from the nozzle into the fuel neck, thus preventing mixing fuel types.
Automatic Shutoff
[0020] The single-spout, dual-channel recyclable-fuel fueling nozzle has the same single-squeeze grip handle with automatic shut off. Certain examples of the single-spout, dual-channel recyclable-fuel fueling nozzle do not have the standard automatic shutoff venturi seen in gasoline and diesel fuel nozzles. The automatic shutoff system will be sensed by the removal of fuel in the spent fuel tank. Once the fuel has been removed, there is no more room in the tank for fresh fuel, so pumping of fresh fuel shuts off.
Environmental Seal
[0021] The single-spout, dual-channel recyclable-fuel fueling nozzle also has the capability to seal itself to the filler neck of the vehicle so as to not let vapor and or fuel escape into the environment. This can be accomplished using a rubber boot around the spout of the nozzle within the filler neck. The nozzle will be of such diameter so that it can not be mistakenly inserted into an existing filler neck of a vehicle using gasoline or diesel.
[0022] Although the present invention has been described in terms of particular embodiments, it is not intended that the invention be limited to these embodiments. Modifications will be apparent to those skilled in the art. For example, a variety of different materials can be used for the various reactor components discussed above.
[0023] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. The foregoing descriptions of specific embodiments of the present invention are presented for purpose of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments are shown and described in order to best explain the principles of the invention and its practical applications, 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. | The current application is directed to a single-spout, dual-channel recyclable-fuel fueling nozzle that extracts spent fuel from a vehicle and introduces fresh fuel into the vehicle via a single filler neck. Liquids move in two different directions within two separate channels of the dual-channel recyclable-fuel fueling nozzle to and from two different reservoirs within the vehicle, including a fresh-fuel reservoir and a spent-fuel reservoir. | 1 |
BACKGROUND AND SUMMARY OF THE PRESENT INVENTION
The present invention relates to a serial shed weaving machine with a weaving rotor. The weaving rotor includes combs having shed retaining elements for the warp threads. The combs form open warp sheds which travel in the warp direction. The weaving rotor also has guide channels comprised of a plurality of channel elements for guiding the weft the threads which are transported by a flowing fluid. Each of the channel elements has an exit gap or slot in a wall to permit exit of the weft thread and is mounted so as to be movable with respect to the other channel elements. The weft exit slot is adapted to be closed in response to movement of the channel elements. Each channel element has its forward and rearward ends (with respect to the weft insertion direction) configured such that when the channel elements of a given guide channel are positioned for weft insertion, the channel elements form a continuous closed guide channel.
Such a serial shed weaving machine is described in German Offenlegungsschrift No. 31 11 780 (corresponding to U.S. patent application Ser. No. 06/241,934). In this known weaving machine, each guide channel is comprised of two combs comprised of dents which may be moved into and out of the midst of the warp threads with the dents forming the channel elements. The dents are relatively thin, and their end faces (i.e., their forward and rearward faces in the weft insertion direction) have complementary wedge surfaces which facilitate the movement of the combs into and out of one another. The dents of each comb are attached to at least one bar which extends over the width of the weaving machine. The bars are operatively connected to drive levers which are controlled via cams mounted on the machine frame to cause movement of the combs into and out of one another.
This known serial shed weaving machine is intended to enable weft insertion by aspirated air, i.e., suction air pressure, rather than blown air. The use of suction air provides not only substantial energy savings but also much more even (non-turbulent) passage of the weft thread and better overall control of the weft insertion. It has been found, however, that due to the thinness of the dents there are a large number of potential leakage locations which interfere with the aim of satisfactory weft insertion by aspirated air. In addition, the drive system for the combs including bars, drive levers, and cams employs a large number of mechanically manipulated and loaded parts which are necessarily subject to undesirable wear.
It is an object of the present invention to improve and refine the known serial shed weaving machine in such a way that the weft threads can be inserted by aspirated air. A further object of the present invention is to provide a serial shed weaving machine in which the system comprising the guide channels and the operating and control arrangement for the channel elements is as simple as possible both structurally and from a manufacturing and systems reliability standpoint. In particular, the system is comprised of a small number of parts which are subjected to minimal mechanical load and stress.
These objects and others are achieved according to the present invention by channel elements having an elongated tubular shape. The length of the channel elements is a multiple of the thickness of one of the shed retaining elements. The elements are movable back and forth in the weft insertion direction by a drive such that when the channel elements are moved in one direction the closed guide channel is opened. At this time, gaps develop between the elements, and each channel element is moved out of the corresponding part of the warp shed. When the channel elements are moved in the other direction, each channel element is moved into the corresponding part of the warp shed and the guide channel is again closed. The total excursion of each channel element in one direction is at least equal to its length in the weft insertion direction.
The inventive use of elongated, tubular, channel-like dents for forming the guide channel instead of the formerly employed narrow, plate-like dents drastically reduces the number of potential leaks, by more than an order of magnitude, such that the weft threads may now be inserted with aspirated air, which provides the advantages mentioned. The fact that the movement of the channel elements is in the weft insertion direction makes it possible to drive and control the elements by simpler arrangements than in the prior art where movement of the dents was rotational in a plane transverse to the insertion direction.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the present invention will be described in greater detail with reference to the accompanying drawings, wherein like members bear like reference numerals and wherein:
FIG. 1 is a schematic longitudinal cross-sectional view of a weaving rotor of a serial shed weaving machine;
FIG. 2 is a perspective view in greater detail of a portion of FIG. 1;
FIG. 3 is a cross-sectional view taken along the lines III--III of FIG. 1; and
FIG. 4 is sequential schematic views for explaining the operation of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1 and 3 are, respectively, longitudinal and transverse cross-sectional views of a weaving rotor of a serial shed weaving machine. During operation the weaving rotor rotates in the direction shown by arrow P in FIG. 3. The operating details and structure of a serial shed weaving machine with a weaving rotor are described in detail in U.S. Pat. No. 4,290,458 issued Sept. 27, 1981 to Steiner which is hereby incorporated by reference. Accordingly, no further description of this operation and structure in detail will be made herein.
The weaving rotor (FIG. 1) has a hollow cylinder 1 which extends over the width of the warp. The rotor is rotatably supported on the machine at the side of the warp threads and is driven by a drive which is likewise disposed on the machine frame at the side. With reference to FIG. 1, the hollow cylinder 1 is supported on its left end face by a flange 2 and on its right end face by a hollow stub or mandrel 3. The flange 2 is rotatably mounted on the left machine wall and the hollow stub 3 is rotatably mounted in a housing 4 which is rigidly attached to the right machine wall. Weft insertion occurs in the direction of arrow A, from left to right as seen in FIG. 1.
On the outer surface of the weaving rotor, guide combs for the warp threads and set-up combs similar to reeds are mounted alternately in the longitudinal direction of the hollow cylinder 1 (and thus in the weft insertion direction A). The outer surface also includes guide channels F for the weft threads. Over the entire surface of the weaving rotor there are 12 to 14 of the guide combs and of the set-up combs and about the same number of guide channels F (FIG. 3).
The guide channels will be described with reference to FIGS. 1 and 2. Each guide channel F is comprised of a number of longitudinally oriented tubular channel elements 5 disposed in a longitudinal sequence along the hollow cylinder 1. One such channel element is shown in a perspective view in FIG. 2. The channel elements 5 have a triangular cross-section, and have a longitudinal gap 6 at their upper longitudinal edge between the two side faces. Their forward and rearward end faces are inclined at a uniform angle. The bevel on the forward end face (in the insertion direction A) of each channel element 5 merges into a tongue section 7 which is bent away from the bottom face of the channel element 5 at the same angle as the forward end face. Further forward, the tongue section runs horizontally from the inclined segment, and then at its free end the tongue section 7 is bent back vertically, i.e., toward the axis of the hollow cylinder 1. This bent-back end 8 of the tongue section 7 acts as a dog for moving the channel element 5.
The weft threads are inserted in the guide channels F formed from the channel elements, by the action of a flowing fluid, in particular air (aspirated air or suction air pressure, for example). For this purpose a connecting element 9 is mounted adjacent to the forwardmost, i.e., furthest downstream, channel element 5 in each guide channel F for connection to tubing 10 or a flexible conduit leading to a suction device (not shown). The connecting elements 9 are disposed outside of the warp threads K, and have the same cross-section and the same end-face inclination as the adjacent channel elements 5. The connecting elements 9 also have dog projections 11 which extend down toward the axis of the hollow cylinder 1. The precise configuration of the projections 11 is arbitrary within wide limits. The connecting elements 9 lack the longitudinal gap 6 which the channel elements 5 have since their outer surface is closed.
For each weft insertion, a weft thread is sucked through the channel elements 5 of each of the guide channels F in the insertion direction A. During this process the respective warp sheds open, with the warp threads K lying over and under the respective guide channels (see the top guide channel F in FIG. 1). After the conclusion of each weft insertion the respective weft thread leaves its guide channel F via the longitudinal gap 6 in the direction away from the axis of the hollow cylinder 1. Then the warp must be closed, which is accomplished by displacing the channel elements 5 by varying amounts in the insertion direction A (as seen in the bottom guide channel F' in FIG. 1). As soon as the new warp shed is open, the channel elements 5 are shifted back in the direction opposite to the weft insertion direction A, and the guide channel F is closed again.
The shifting of the channel elements 5 back and forth in the insertion direction A is accomplished by a drive mechanism which is disposed between the hollow cylinder 1 and the channel elements 5 and which act on the dogs 8 and 11 of the channel elements 5 and the connecting elements 9, respectively. As shown in the Figures, a drive mechanism is provided for each guide channel F by two bands or flat bars 12 and 13 disposed one above the other. On the weft insertion side these bars are attached to the flange 2 via tension springs 14 and 15, respectively. One of the bands (in the illustrated embodiment the outer band 13) is attached on its weft exit end to the drive mechanism.
The bands 12 and 13 have openings 16 and 17, respectively, in which the dogs 8 and 11, respectively, are engaged. In this way, when the bands 12 and 13 move back and forth in the insertion direction A the channel elements 5 and the connecting elements 9 execute a similar motion.
The drive mechanism of the bands 12 and 13 according to FIG. 1 comprises a cable 18, one end of which is attached to the outer band 13. The other end of the cable 18 is attached to the hollow cylinder 1. Movement of a pulley 19 around which cable 18 is passed is controlled by a cam 20 in the form of a curved slot. The cam 20 is milled into a bushing 21 which is rigidly attached to the housing 4. Thus, the cam 20 is rigidly attached to the machine frame. The pulley 19 is mounted on a rod 22 which is mounted in turn on two bearing rods 23 so as to be slidable back and forth in the insertion direction A. The rod 22 has a pickup cylinder 24 on one end, which cylinder engages the cam 20. The bearing rods 23 are attached to a rotatable disc 25 which is rigidly attached to the hollow stub 3 to rotate with respect to the housing 4 and the cam 20.
When the hollow cylinder 1 rotates, and the weaving rotor with the guide channels F thus rotates along with the cylinder, the guide rods 22 and the pickup cylinders 24 follow the cam slots 20. In this way, the pulleys 19 are shifted between the end positions shown on the top and on the bottom of FIG. 1. Each outer band 13 and each channel element 5 executes a translational movement twice that of the corresponding pulley 19 due to the block and tackle action of the cable 18 and the pulley 19. Since the dogs 8 and 11 of the channel elements 5 and the connecting elements 9, respectively, extend through the respective openings 16 and 17 of both bands 12 and 13, the motion of the outer bands 13 is transmitted to the respective inner bands 12 via the dogs 8 and 11.
The configuration of the cam slot 20 and the positions and sizes of the openings 16 and 17 in bands 12 and 13 are arranged in a predetermined manner. Starting with the position of the channel elements 5 shown on the top in FIG. 1 wherein the channel elements form a closed guide channel F, the channel elements are moved in the following sequence. As soon as weft insertion in a given guide channel F is completed, the pulley 19 is moved in the insertion direction A whereby the outer band 13 is moved in the same direction. In this way, in a first stage a gap S is produced between all the channel elements 5 so that the warp threads K can pass through from a lower to an upper shed position. The size of these gaps S, which in practice is about 1-2 mm, is limited by the inner band 12. The inner band 12 also maintains the gaps S over the course of further shifting of the channel elements 5.
It should be noted that the flange 2 has a matching stop surface 26 for each guide channel F. Each such surface has a bore hole 27 through which the weft thread is sucked into the guide channel F. The weft thread is supplied up to or into the bore hole 27 by a suitable supply means (not shown).
In a second stage, the pulley 19 is moved further in the weft insertion direction A, shifting all the channel elements 5 in the same direction until the point that the expanded guide channel F has moved a distance away from the stop surface 26 equal to the length of a channel element 5 plus one gap length S. In this position (F' at the bottom of FIG. 1), the gaps S have been maintained. As a consequence of the configuration of the tongues 7, this shifting of the channel elements 5 causes the warp threads K in the lower shed position to move into the upper shed position, over the path opened up through the gaps S between the channel elements 5. At the bottom position in FIG. 1, all the warp threads K in the segment of the warp not occupied by channel elements 5, namely those in the segment adjacent to the stop surface 26, are shown also in the upper shed position. This is not necessarily the situation, since the threads K in this free segment will likely take a position intermediate between the upper and lower shed position, as determined by the shed geometry. When the weaving rotor is rotated further, the channel elements 5 will be rotated out of the plane of the warp threads, and all the warp threads K will be free to assume the closed shed position. In this position, setting up, i.e., beating up, of the weft thread is carried out.
The weaving rotor then executes a relatively large rotational excursion with the guide channel F' open until this open guide channel F' again comes upon warp threads K, which threads meanwhile have undergone a shed inversion motion. In the free segment opened up by the movement of the channel element 5 which is on the weft entry side, namely the space between the stop surface 26 and the expanded guide channel F', the warp threads K have already returned to the upper and lower shed positions, i.e., the shed is now open. Over the remainder of the width of the warp, the warp threads of the lower shed position cannot reach that position, due to the channel elements 5 which intervene. Instead, the threads of the lower shed position press under tension against the outer edge of the channel elements 5 where the gap 6 is.
The pulley 19 is then moved in the direction opposite to the insertion direction, and in a third stage the channel elements 5 are moved against the stop surface 26 such that the gap adjacent the stop surface 26 is closed and the gaps S (which have remained open during the movement) are all that remains open. Thus, the motion in the third stage, in which springs 14 and 15 assist in the movement of the bands 12 and 13, respectively, is the opposite of the movement in the second stage.
When the individual channel elements 5 are shifted, the warp threads K intended for the lower shed position pass through the corresponding gaps S into the lower shed position, so that each channel element 5 ends up within an open warp shed segment. At the conclusion of the third stage the weft-insertionside end of the inner band 12 strikes a detent 28 mounted on the flange 2 to prevent the band from moving further toward the flange 2.
At this point, the guide channel has the same lateral position as after the first stage, i.e., the only gaps are the gaps S. The pulley 19 is now moved further in the direction opposite to the insertion direction, in a fourth stage, in which the movement is the opposite of the movement in the first stage. In the process, the gaps S are now closed and the guide channel returns to the position shown on the top of FIG. 1, where the channel is now again ready for weft insertion. The action of the spring 15 ensures that the channel elements 5 press against each other and against the stop surface 26, so that the guide channel F is airtight in the longitudinal direction and free of leaks.
The opening and closing of the weft channels F which are described here in terms of sequences of operations will be further described infra in quantitative terms, with reference to FIG. 4, where the arrangement and widths of the openings 16 and 17, and the distances of the excursions, will be discussed.
As mentioned previously, the weft is inserted by suction. This imposes the requirement that the guide channel F be sealed, i.e., leak-free, along its length including the end connections. The manner in which the guide channel F is closed in its longitudinal direction was described supra. It must also be airtight in the radial direction. In other words, the gaps 6 in the channel elements 5, which gaps are present to enable the weft thread to exit from the guide channel F, must also be closed during weft insertion. This is described in the following.
With reference to FIGS. 2 and 3, each channel element 5 has two projections 29 on each of its two side faces. Shaped plates 30 are mounted on the hollow cylinder 1 (FIG. 3), which plates 30 serve to support the channel elements 5 and, by acting on the projections 29, to close the gaps 6. Each shaped plate 30 has a jaw on its end which extends outwardly away from the hollow cylinder 1. The jaw comprises an opening bounded by two side members 31 and two supports 32. The gap between the supports 32, on which supports the channel elements 5 rest, is wider than the width of the tongue 7. Adjacent to the supports 32 in the direction toward the hollow cylinder 1, there is an opening 33 for the bands 12 and 13 to pass through the shaped plate 30. Thus, the openings 33 hold and confine the bands 12 and 13, and the supports 32 support and guide the channel elements 5.
The jaw of the shaped plates 30 has a truncated triangular cross-section corresponding to the cross-sectional shape of the channel elements 5. However, the triangle of the jaw is larger, so that as soon as and, as long as, the projections 29 are moved away from direct engagement with the side members 31, the gap 6 is open. When the channel elements 5 are shifted so that the projections 29 move between the side members 32, the side surfaces of the channel elements 5 on which the projections 29 are mounted are pressed together and the gap 6 is closed. Since the shaped plates 30 are rigidly mounted to the hollow cylinder 1, the gaps 6 are opened and closed automatically as the channel elements 5 undergo the described shifting forward and backward in the weft insertion direction A.
In the open state, the gap 6 is about 1 to 2 mm wide, which is adequate for the weft thread to exit. This gap occurs automatically when the guide channel F is opened, i.e., expanded longitudinally. The warp threads K which thereby move into the upper shed position will carry the weft thread toward and through the gaps 6. This process is aided by the triangular cross-section of the channel elements 5.
The opening of the gap 6 when the projections 29 are moved out of the jaws of the shaped plates 30 is automatic and unaided. To accomplish this automatic opening, the channel elements 5 are manufactured such that in the rest state they have a longitudinal gap 6 of the prescribed width. The channel elements 5 are molded in a single piece with the tongues 7 and dogs 8, of a suitable plastic material, e.g., a polyamide such as nylon 6. In order to minimize the amount of force needed to close the gap 6, the walls of the channel elements 5 have thinned regions at the two edges between the bottom surface and the side surfaces (so-called "film hinges") in the form of the grooves 34.
FIG. 3 is a cross-sectional view of the weaving rotor shown schematically in FIG. 1. With particular reference to FIG. 3, the configurations of the set-up combs 35 and the guide combs 36, and the arrangement of these combs with the guide channels F on the outer surface of the hollow cylinder 1 is illustrated.
The set-up combs 35, i.e., reeds, are comprised of set-up dents 37 disposed equidistant along the hollow cylinder 1 for setting up the inserted weft threads. The guide combs 36 are comprised of guide dents 38 also disposed in lines along the hollow cylinder 1. Alternating in the spaces between the guide dents, shed retaining elements 39 are mounted for holding the warp threads K in the upper and lower warp shed positions.
The shed retaining elements 39 for the upper shed position are in the form of projections on one side of the guide dents 38. Since the warp threads K for the upper shed position lie on the shed retaining elements 39 under tension, shed retaining elements for the lower shed position are not required. It is sufficient if an appropriate amount of free space is available above the surface of the hollow cylinder 1 for the threads of the lower shed position to pass and be held by virtue of the tension on them. Suitable spacers 40 are provided between the dents of each set-up comb 35, as well as between the dents of each guide comb 36.
The shed retaining elements 39 thus serve to position the warp threads K in the lower as well as the upper shed positions over the extent of the angle over which the warp threads pass around the weaving rotor. The thus formed warp sheds extend one ahead of the other up to the fell of the fabric. The individual weft threads are inserted into the corresponding sheds in steps at spaced distance intervals at the time when the sheds are open.
The parts of the set-up dents 37 and the guide dents 38 which extend out from the surface of the hollow cylinder 1 have a bent-finger shape, with the bend being in the direction opposite to the rotational direction P of the weaving rotor. As seen in FIG. 3, the inner edges of the guide dents 38 and the leading external edges of the set-up dents 37 (in the rotation direction P) define a channel-like space 41 which extends over the width of the warp. The guide channels F are disposed in respective spaces 41.
The outer part of the hollow cylinder 1 (FIG. 3) has L-shaped grooves for holding the set-up combs 35 and the guide combs 36. Between each associated pair of combs and radially below the channel-like space 41 there is an open channel 42 which extends over the width of the warp and in which the shaped plates 30 and the bands 12 and 13 are disposed. The open jaws of the shaped plates 30 which support the channel elements 5 extend radially outwardly into the corresponding channel-like spaces 41.
The thickness of the set-up dents 37 and the guide dents 38 which make up the set-up and guide combs 35 and 36 are approximately the same as the thickness of ordinary reed dents. The intermediate open spaces for the lower shed position of the warp threads are also about the thickness of a reed dent. The thickness of the shed retaining elements 39 for the upper shed position of the warp threads is a multiple of this thickness. Generally when the desired product is changed the set-up combs 35 and the guide combs 36 are changed. The type of product produced and the types of warp and weft materials used do not have a bearing on the parameters of the channel elements 5 (and thus the guide channels F). Therefore there is no need to change the channel elements 5, the shaped plates 30, the bands 12 and 13, or the drive mechanism for the bands (FIG. 1) when changing the desired product.
FIG. 4 is a schematic representation of the opening and closing of a guide channel F in terms of three states: I, II and III. The stop surface 26 of the flange 2, and the positions of the channel elements 5 and the bands 12 and 13 are shown for each of these states. Beneath the cross-sectional views of the bands 12 and 13, corresponding schematic plan views of these bands are shown, giving the positions and sizes of the openings 16 and 17 as well as the positions of the dogs 8 in these openings. For the sake of simplicity, only four channel elements 5 1 to 5 4 are shown.
In state I, the guide channel F is closed. To reach state II, in which the gaps S are open, the bands 12 and 13 are moved in the direction of arrow B (the first stage in the discussion supra). Additional movement of the bands in the direction of arrow C yields state III (second stage in the discussion supra), in which the guide channel is completely open (i.e., with all the gaps S open) and the gap between the stop surface 26 and the closest channel element 5 4 is equal to the length of a channel element plus the width of a gap S. In the third stage (see discussion supra) the guide channel is moved back in the direction of arrow D, to reestablish state II, and in the fourth stage the guide channel is moved back in the direction of arrow E to reestablish state I.
The length of each channel element 5, which in practice will be about 100 mm, is designated L. The width of a gap S is designated b. When the gaps S are opened in the first stage, the first channel element 5 4 must be moved away from stop surface 26 by the distance b in the direction of arrow B. The second channel element 5 3 must be moved a distance 2b with respect to stop surface 26; the third element, a distance 3b; and so forth. In this way, the guide channel F is opened from its forward end, i.e., from the weft exit end. The movement proceeds as follows: first, the forwardmost channel element 5 1 is moved in the direction of the arrow B by just the distance b, at which point the next channel element 5 2 begins to move, while the forwardmost element 5 1 is carried along farther. At the conclusion of the first stage the channel element 5 4 which is located at the stop surface 26 is moved along by the distance b. The connecting element 9 (FIG. 1) is not engaging any warp threads, and therefore there is no need to produce a gap between it and the forwardmost channel element 5 1 . Accordingly, the connecting element 9 may have its dog 11 rigidly connected to the band 13.
The dog 8 of the forwardmost channel element 5 1 may also be rigidly connected to the outer band 13. In the illustrated embodiment, this dog 8 extends into an opening 17 having a width a slightly greater than the thickness c of the dog 8. The width of the opening 17 for the dog 8 of the next channel element 5 2 behind the forwardmost element 5 1 is (a+b). Similarly, the width of the opening 17 for the dog 8 of the n-th channel element is [a+(n-1)b]. The spacing between the forward edges (with respect to arrow B) of adjacent openings 17 is L.
The inner band 12 serves to maintain the gaps S during the second and third stages. This band is not moved directly but through the intermediary of the dogs 8 which are moved by the outer band 13 and extend into the openings 16 of the inner band 12. Therefore, the relationship between the individual openings 16 is the reverse of that between the corresponding openings 17. Thus, the opening 16 associated with the forwardmost channel element 5 1 is the widest opening in the band 12, and the rearmost opening 16 is the narrowest.
In state I (FIG. 4), the distance between the rear edge of the openings 16 and the forward side of the associated dog 8 is the same for all openings 16, namely d. The distance d is greater than the thickness c of the dogs. The purpose of this is to leave room so that when state I is reached after the fourth stage, with the gaps S re-closed, the spring 15 (FIG. 1) will pull all the channel elements 5 to the stop point provided by stop surface 26. In this way, the sealing of the guide channel F is ensured. Preferably, the cable 18 (FIG. 1) is also attached to band 13 with play, to ensure the sealability of the guide channel F under the influence of the action of the spring 15.
The overall width of the rearmost opening 16 (associated with the rearmost channel element 5 4 ) is d+b; that of the next opening 16 is d+2b; and that of the opening 16 associated with the n-th channel element is d+nb. In comparing the widths of the openings 16 and 17 it should be noted that in the formula for the openings 16, n=1 for the channel element 5 located at or adjacent to the stop surface 26, while in the formula for the openings 17, n=1 for the channel element 5 located at or adjacent to the connecting element 9 (FIG. 1).
After the completion of the first stage, all the dogs 8 are at the forward edges of the openings 16, and thus at the beginning of the second stage the inner band 12 is in the process of being moved in the direction of arrow C along with the outer band 13. This movement of the band 12 is against the force of the spring 14 (FIG. 1). As is seen from the diagrams for the states II and III (FIG. 4), the dogs at this point are also positioned against the rear edges of the openings 17, and thus are simultaneously subjected to the force of these rear edges and the forward edges of the openings 16. This ensures that the gaps S will remain open in the second and third stages and will re-close only after the rear end of inner band 12 hits the detent 28 (FIG. 1), in the fourth stage.
The principles, preferred embodiments and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. The embodiments are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations and changes which fall within the spirit and scope of the present invention as defined in the claims be embraced thereby. | The present invention relates to a serial shed weaving machine with a weaving rotor. Guide channels for weft threads transported by a flowing fluid are mounted on the weaving rotor. The guide channels are formed from a plurality of elongated, tube-like channel elements having a closable weft thread exit gap. The channel elements have complementary end configurations such that they can be moved together to form a closed guide channel. The channel elements are movable back and forth in the weft insertion direction. When the channels are moved in a first direction, the closed guide channel is opened and gaps are formed between the channel elements and each channel element is moved out of its associated part of the warp shed. When the channel elements are moved in a second direction, each channel element is moved back into its associated part of the warp shed and the guide channel is closed. The total excursion of each channel element in each direction is at least as great as the length of the element. Since the motion of the channel elements is exclusively back and forth in the weft insertion direction, the drive for such motion is relatively simple. Further, since the channel elements are each several centimeters long, the number of possible leak locations is sharply reduced over the prior art such that the weft threads may be inserted by suction air pressure. | 3 |
TECHNICAL FIELD
[0001] This disclosure relates to vehicles that have a combustion engine and an electric traction motor that cooperate to provide torque to drive the vehicle and to a control algorithm for starting the engine with either a starter motor or the electric traction motor.
BACKGROUND
[0002] Vehicle manufacturers are developing hybrid vehicles to meet the demand for more fuel efficient vehicles. One configuration for a hybrid vehicle may be referred to as a Modular Hybrid Transmission (MHT) vehicle design. In a MHT vehicle, an electric machine is sandwiched between conventional automatic step ratio transmission and the engine. The electric machine is attached to the transmission impeller or input shaft. The engine is selectively disconnected from the transmission using special “disconnect clutch”. The disconnect clutch allows vehicle to be driven under electric power alone, in hybrid mode with both electric machine and the engine propelling the vehicle, or in a combustion engine only mode where vehicle is propelled by the engine only.
[0003] Better fuel economy engine may be achieved by shutting down the engine when vehicle is decelerating and restarted when the driver depresses the accelerator pedal, or “tips in.” The engine may be disconnected from transmission and regenerative braking can be initiated when the brakes are applied to capture vehicle kinetic energy.
[0004] One problem with MHT vehicles is that the electric machine may not be able to provide the requested additional torque without the engine. For example, when the driver demands a large increase in torque (or in extreme cases the driver demands wide open throttle) in the middle of regenerative braking or when the vehicle was stopped with the engine shut down and disconnected, the engine has to be restarted quickly to provide adequate torque to meet the driver's demand for torque.
[0005] The engine is normally started by the electric machine with the disconnect clutch applied. Starting the engine with electric machine requires a certain portion of the electric machine torque to be used for the engine restart further slowing or delaying vehicle launch.
[0006] This disclosure is directed to solving the above problem and other problems associated with hybrid vehicles as summarized below.
SUMMARY
[0007] The engine of a vehicle having an MHT configuration is typically started by applying disconnect clutch and connecting the engine to the electric machine. MHT vehicles are also equipped by 12V starter that is quite often used if the high voltage battery is depleted or ambient temperature is very low limiting operation of the high voltage battery or when the electric drive is otherwise not operational. The starter is rarely used outside of these conditions for engine starts.
[0008] The electric machine is normally used to start the engine because one of the limitations of the MHT configured vehicle is the durability of the starter motor. It is expected that the engine will experience more than one million starts over the life of the hybrid vehicle. Regular starters have expected life of 100,000 cycles and enhanced starters (specifically designed for Stop/Start systems) have expected life of 300,000. Restarting the engine requires significant torque that is not available for vehicle propulsion. Starting the engine and engaging the disconnect clutch to its full torque capacity can take 600 to 900 msec. depending on the type of engine. Restarting the engine is particularly troublesome when the driver demands high acceleration by doing hard tip-in and the engine is shut down with the disconnect clutch disconnected.
[0009] In this disclosure, the vehicle controller receives an input signal from the accelerator pedal and calculates a driver demand torque. If the driver demand torque exceeds certain calibrated threshold torque all of the electric machine torque will be used to propel the vehicle. The engine may then be restarted using 12V starter. The engine speed is increased and commanded to match electric machine speed. The disconnect clutch is applied when the speed of the engine is within a calibrated range relative to the speed of the e-machine.
[0010] Optimal propulsion torque is provided by the vehicle in the hybrid mode with both the electric machine and the combustion engine operating. If the driver demand torque is below the threshold when the engine is to be restarted, the e-machine is used to restart the engine. The durability of the starter is not a concern because the 12 volt starter is used to restart the engine only when there is a high driver demand for torque (eg. wide open throttle demanded).
[0011] According to one aspect of this disclosure, a hybrid vehicle driveline apparatus is provided that maximizes the torque available to provide traction from the motor while starting the engine when a there is a request for additional torque and the engine is stopped. The apparatus includes an engine that may be stopped to increase fuel economy. The engine has a starter that provides torque to start the engine independently of the electric machine. A stepped gear ratio automatic transmission and a motor are operatively connected between the engine and the transmission. The motor is selectively connected to the engine by a clutch. A torque demand request apparatus is adapted to provide a torque demand request signal. A controller receives the torque demand request signal and provides either an engine start signal to the starter when the engine is stopped and the torque demand request signal is greater than a predetermined value or motor torque request signal to the motor when the engine is stopped, the clutch is applied, and the torque demand request signal is less than or equal to the predetermined value.
[0012] According to other aspects of this disclosure, the torque command request apparatus may be an accelerator pedal that includes a pedal position sensor that provides a pedal position signal to the controller. The apparatus may further comprise a motor speed signal and an engine speed signal provided to the controller that applies the clutch when the motor speed signal and the engine speed signal are within a calibrated threshold difference. The motor speed signal and the engine speed signal may be monitored by the controller after the clutch is applied and the controller increases the pressure applied by the clutch to lock-up the clutch. The controller may send a maximum torque application signal to the motor before the starter motor is actuated.
[0013] According to another aspect of this disclosure a method is disclosed for operating a vehicle having a motor between a transmission and an engine. The motor and the engine may be connected through a clutch that selectively connects the motor and the engine. The vehicle may have an accelerator pedal including a pedal position sensor that provides a pedal position signal. The pedal position signal is provided to a controller when the motor is operating and the engine is stopped. A starter motor is provided to start the engine when the pedal position signal is greater than a threshold. Engine speed is increased to within a calculated range of speed relative to the motor and the clutch is applied when the engine speed is within the calculated range.
[0014] According to other aspects of the disclosed method, the pedal position signal is provided to the controller when the pedal position exceeds a threshold minimum value. The method may further comprise obtaining a motor speed signal, an engine speed signal, and applying the clutch when the motor speed signal and the engine speed signal are within a calibrated threshold difference of each other. The motor speed signal and the engine speed signal are monitored after the clutch is applied and the pressure applied by the clutch is increased to lock-up the clutch. A maximum torque application signal is provided to the motor before the starter motor is actuated.
[0015] According to another aspect of this disclosure, a system is disclosed for starting an engine of a vehicle that has a motor that is selectively coupled to the engine by a clutch. The system comprises an engine control module, a pedal position sensor that provides a pedal position signal to an engine control module, and a starter motor actuated by the engine control module based upon the pedal position signal. The engine control module sends a clutch apply signal to the clutch to apply the clutch when the engine speed is within a predetermined range of the motor speed.
[0016] The pedal position sensor may provide the pedal position signal to the engine control module when the pedal position exceeds a threshold minimum value. A motor speed signal and an engine speed signal are compared to each other and the clutch is applied when the motor speed signal and the engine speed signal are within a calibrated threshold difference. The motor speed signal and the engine speed signal may be monitored after the clutch is applied and the pressure applied by the clutch is increased to lock-up the clutch. The engine control module may send a maximum torque application signal to the motor before the starter motor is actuated.
[0017] The above aspects of this disclosure and other aspects will be better understood in view of the attached drawings and the following detailed description of the illustrated embodiments of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1A is a diagrammatic view of a modular hybrid transmission system for a hybrid vehicle that does not include a torque converter;
[0019] FIG. 1B is a diagrammatic view of an alternative embodiment of a modular hybrid transmission system for a hybrid vehicle that includes a torque converter;
[0020] FIG. 2 is a flowchart of an algorithm for controlling a starter for a combustion engine or an electric machine depending upon the torque demanded;
[0021] FIG. 3 is a graphical representation of several vehicle operating parameters as impacted by an engine start procedure using the electric machine; and
[0022] FIG. 4 is a graphical representation of several vehicle operating parameters as impacted by an engine start procedure using the engine starter.
DETAILED DESCRIPTION
[0023] A detailed description of the illustrated embodiments of the present invention is provided below. The disclosed embodiments are examples of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed in this application are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art how to practice the invention.
[0024] Referring to FIGS. 1A and 1B , a modular hybrid transmission 10 is shown in a diagrammatic form. An engine 12 is operatively connected to a starter 14 that is used to start the engine 12 when additional torque is needed. A motor 16 , or electric machine, is operatively connected to a driveline 18 . A disconnect clutch 20 is provided on the driveline 18 between the engine 12 and the electric machine 16 . A step shift geared automatic transmission 22 , or gear box, is also provided on the driveline 18 . Torque transmitted from the engine 12 and motor 16 is provided through the driveline 18 to the transmission 22 that provides torque to the wheels 24 . As shown in FIG. 1A , launch clutch 26 A is provided between the transmission 22 and the engine 12 and/or motor 16 to provide torque through the transmission 22 to the wheels 24 . As shown in FIG. 1B , a torque converter 26 B is provided between the transmission 22 and the engine 12 and/or motor 16 to provide torque through the transmission 22 to the wheels 24 . While elimination of the torque converter is an advantage of the embodiment of FIG. 1A , the present disclosure is also advantageous in reducing vibrations in systems having a torque converter 26 B like that shown in the embodiment of FIG. 1B .
[0025] The vehicle includes a vehicle system control (VSC) for controlling various vehicle systems and subsystems and is generally represented by block 27 in FIG. 1 . The VSC 27 includes a plurality of interrelated algorithms which are distributed amongst a plurality of controllers within the vehicle. For example, the algorithms for controlling the MHT powertrain are distributed between an engine control unit (ECU) 28 and a transmission control unit (TCU) 29 . The ECU 28 is electrically connected to the engine 12 for controlling the operation of the engine 12 . The TCU 29 is electrically connected to and controls the motor 16 and the transmission 22 . The ECU 28 and TCU 29 communicate with each other and other controllers (not shown) over a hardline vehicle connection using a common bus protocol (e.g., CAN), according to one or more embodiments. Although the illustrated embodiment depicts the VSC 27 functionality for controlling the MHT powertrain as being contained within two controllers (ECU 28 and TCU 29 ) other embodiments of the HEV include a single VSC controller or more than two controllers for controlling the MHT powertrain.
[0026] Referring to FIG. 2 , the algorithm disclosed for operating the vehicle 10 in one embodiment is illustrated by the flowchart 30 . The algorithm begins at start 32 . The vehicle is ready for launch, at 34 , with the electric motor 16 spinning at idle speed and the combustion engine 14 off. The position of a pedal position sensor is read, at 36 . The pedal position sensor provides a pedal position signal. The pedal position signal is analyzed, at 38 , to determine whether the pedal position signal is greater than the calibrated threshold signal. If the pedal position is requesting more torque than the calculated threshold, at 38 , the controller commands that maximum torque be provided to the electric machine, at 40 . The electric machine 16 provides torque as rapidly as possible without requiring that a portion of the torque from the electric machine 16 be used to start the combustion engine. The 12 volt starter is turned on, at 42 , to start the engine 12 .
[0027] Engine speed is monitored, at 44 , by an engine speed sensor. It is determined whether the engine speed is greater than the first combustion event threshold, at 48 . If so, the command engine speed is set to equal the electric machine speed, at 50 . At 52 , it is determined whether the engine speed is within the calibrated range of the electric machine speed. Generally, it is preferred that the engine speed be within a limited range of matching the electric machine speed. Upon matching speeds, at 52 , the disconnect clutch is applied, at 56 , thereby connecting the combustion engine 14 to the driveline 18 . At 58 , it is determined whether the absolute value of the difference between the electric machine speed and the engine speed is less than a calibrated threshold. If so, pressure is applied to lock the disconnect clutch, at 60 . The algorithm is completed, at 62 .
[0028] If the absolute value of the difference between the electric machine speed and the engine speed is determined to be equal to or greater than the calibrated threshold, the system increases disconnect clutch pressure applied at 64 incrementing the clutch pressure in a loop until the absolute value of the difference between the electric motor speed and engine speed is less than the calibrated threshold, at 58 .
[0029] If the pedal position is not greater than the calculated threshold, at 38 , the system determines whether the pedal position is equal to zero indicating that the driver is not requesting torque as indicated by the driver not depressing the accelerator pedal, at 66 . If the pedal position is not at zero, the electric machine vehicle launch is executed and the combustion engine 14 may be started using the electric machine torque output to start the engine, at 68 . The brake is released as the accelerator pedal is depressed. Under this condition, the algorithm ends, at 70 . If the pedal position at 66 is not equal to zero, the system determines whether the brake is released, at 72 . If the brake is released, the controller executes a creep strategy launching the electric machine with a gradually increasing torque output. Again, if required, the engine 14 may be started using the electric machine 16 , at 74 , and the algorithm under these conditions concludes, at 76 .
[0030] Referring to FIG. 3 , starting the combustion engine 14 using an electric machine is illustrated in several synchronous charts of engine operating parameters. The pedal position is illustrated by the line 80 . Initially, the pedal is not depressed, but is then fully depressed to a wide open throttle or 100% condition. The pedal position line represents the driver torque demand. The engine motor speed line 82 is initially at a relatively low level, but upon depression of the accelerator pedal, the electric motor speed increases to its maximum speed.
[0031] At the same time, the disconnect clutch pressure, which may also be understood as the torque capacity line is illustrated by the line 84 , and is initially zero and then gradually increases as the electric motor speed increases to a maximum disconnect clutch pressure shown by line 84 . The engine speed represented by line 86 is initially zero, and after a period of delay measured from the time at which the pedal is fully depressed, the engine speed slowly begins to increase. As shown, the engine speed may actually over-shoot the electric motor speed and may require a reduction in speed to achieve synchronization with the electric motor speed. The torque required to start the engine reduces the rate of increase of the electric motor speed shown by line 82 . The electric machine and engine torque is illustrated by line 88 to be initially at a relatively low level. The combined torque is reduced initially due to torque losses caused by engine cranking The combined torque is also reduced as a result of the need to allow the engine speed to be synchronized with the electric machine speed. Finally, vehicle speed is initially zero or relatively low and then increases following the general increase in total torque, as shown by line 90 .
[0032] Referring to FIG. 4 , the engine start procedure using the 12 volt starter is shown in a series of graphs similar to those shown in FIG. 3 to illustrate the greater responsiveness in torque output when the engine is started using the 12 volt starter instead of the electric machine. The pedal position is shown by line 92 , which shows that the identical command is provided as in FIG. 3 by compressing the pedal from zero to wide open throttle. Electric motor speed, shown by line 34 , is initially a relatively low rate of speed that is constantly increased to a maximum speed. The disconnect clutch pressure, or torque capacity, is shown by line 96 . The disconnect clutch is not initially engaged but then begins to increase as the engine begins to crank. When the engine speed begins to catch up to the synchronous speed, as shown by line 98 , the disconnect clutch pressure increases rapidly to a maximum level. The combined electric machine and engine torque is illustrated by line 100 . Line 100 begins with a low level of torque flowing from the electric motor. As the disconnect clutch 20 gains torque capacity, engine torque is added to the electric machine torque to a maximum illustrated by line 100 . The vehicle speed, illustrated by line 102 , is initially shown to be zero with a constant increase in speed that is increased at a more rapid rate as the engine speed increases to the maximum as illustrated by line 102 .
[0033] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention. | A control system including a method and apparatus for operating a hybrid vehicle. A disconnect clutch selectively separates an electric machine from a combustion engine. If a wide open throttle or high torque command is requested and the combustion engine is shut down, a 12 volt starter may be used to start the combustion engine while disconnected from the electric machine and all of the electric machine torque available may be used for traction. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of and claims the benefit of priority under 35 U.S.C. §120 from U.S. application Ser. No. 11/091,416, filed Mar. 29, 2005, the entire contents of which are incorporated herein by reference. U.S. application Ser. No. 11/091,416 claims the benefit of priority under 35 U.S.C. §119 from Japanese Patent Application No. 2004-096455, filed respectively on Mar. 29, 2004.
FIELD OF THE INVENTION
The present invention relates to a plasma processing apparatus and method; and, more particularly, a plasma processing apparatus and method using a processing chamber for performing a plasma processing on a substrate.
BACKGROUND OF THE INVENTION
Recently, a treatment using a plasma (hereinafter, referred to as “plasma processing”) such as an etching, sputtering and CVD (chemical vapor deposition) has been employed to be performed on an object to be processed such as a semiconductor wafer (hereinafter, referred to as “wafer”) in a manufacturing process of a semiconductor apparatus.
An apparatus for carrying out such process (shown in FIG. 8 ) has a processing chamber 800 , which is a cylindrical container, for performing a plasma processing on a wafer. The processing chamber 800 includes a chamber sidewall 810 , an upper electrode 811 installed at the top of the chamber 800 , a lower electrode 812 installed in a lower portion of the processing chamber 800 , an ESC (electrostatic chuck) stage 820 and a focus ring 821 mounted on an upper side of the lower electrode 812 , and a baffle plate 830 interposed between the chamber sidewall 810 and the lower electrode 812 .
The upper electrode 811 , which has a plurality of through holes not shown in the drawing, serves as a shower head for introducing a process gas for the plasma processing into the processing chamber 800 through the through holes. The lower electrode 812 is connected to a high frequency power supply 813 . The focus ring 821 is made of a ring-shaped member formed to enclose a wafer mounted on the upper side of the ESC stage 820 .
The ESC stage 820 includes an ESC electrode 820 a embedded in the ESC stage 820 to electrostatically adsorb the mounted wafer onto the ESC stage 820 . The ESC electrode 820 a is connected to a variable power supply 822 for providing electric power required to adsorb the wafer onto the ESC electrode 820 a.
In the plasma processing apparatus shown in FIG. 8 is formed a plasma region of the plasma generated by a high frequency electric field formed in a space between the upper electrode 811 and the lower electrode 812 as shown in the figure. The plasma processing apparatus performs an etching on, for example, an oxide film already formed on an upper side of the wafer by the generated plasma. The particles detached from an inner wall of the chamber sidewall 810 by the etching float around inside the processing chamber 800 . After the etching is completed, the particles are removed by exhausting the processing chamber 800 through a small through hole (not shown) located in the baffle plate 830 by using a pump which is not shown.
Such particles are negatively charged by the electrons in the plasma to float around the plasma region above the wafer during the etching process, and will be attached onto the upper side of the wafer to thereby contaminate the wafer after the plasma production is stopped by completing the etching process.
There are disclosed techniques that can be employed to prevent the particles from being attached onto the upper side of the wafer as described above, wherein the charged particles are actively removed by using another electrode installed in the processing chamber 800 before the plasma generation or after the plasma extinction (for example, References 1 and 2).
(Reference 1) Japanese Patent Laid-open Application No. H10-284471 (Reference 2) European Patent Publication No. 1119030
However, although the particles can be driven from the region above the wafer towards the other electrode before the plasma being generated or after the plasma being extinguished by the techniques described in References 1 and 2, it is not practical to remove the particles while the plasma is being produced because the other electrode causes to generate an abnormal discharge or to produce particles during the plasma generation.
Further, since the particles in the region above the wafer effectively mask the parts to be processed on the wafer to thereby reduce the yield, it is required that these particles have to be purged out of the region above the wafer especially while the plasma is being generated. In addition, by suppressing the yield reduction, the productivity is expected to improve.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide a plasma processing apparatus and method for inhibiting the attachment of the particles to prevent the contamination of the wafer.
It is a second object of the present invention to provide a plasma processing apparatus and method for removing the particles from the region above the wafer during the plasma generation to enhance the productivity.
In accordance with one aspect of the present invention, there is provided a plasma processing apparatus comprising a plasma generating unit for generating a plasma in a processing chamber in which a set processing is performed on a substrate serving as an object to be processed, the plasma processing apparatus further comprising a particle moving unit for electrostatically driving particles in a region above the substrate to thereby be removed out of the region above the substrate in the processing chamber while the processing on the substrate is performed by using the plasma.
Preferably, the particle moving unit includes: a mounting table for mounting the substrate; a first electrode for electrostatically adsorbing the substrate onto the mounting table; a ring-shaped member installed to enclose a periphery of the substrate; a second electrode for electrostatically adsorbing the ring-shaped member onto the mounting table; a first power supply, connected to the first electrode, for supplying an electric power with a first electric potential; and a second power supply, connected to the second electrode, for supplying an electric power with a second electric potential different from the first electric potential, wherein the mounting table, the first electrode, the ring-shaped member, and the second electrode are installed in the processing chamber.
Preferably, the particle moving unit includes a voltage controller for controlling at least a potential of the second electrode to remove the particles from the region above the substrate to a region above the second electrode.
Preferably, the second electric potential is higher than the first electric potential when the particles are negatively charged during the plasma processing.
Preferably, the first electric potential is of negative polarity and the second electric potential is of positive or negative polarity.
Preferably, the second electric potential is higher than an electric potential formed near a surface of the substrate in the region above the substrate in response to the first electric potential or a self-bias potential formed by the generation of the plasma.
Preferably, the plasma processing apparatus further comprises a particle removing unit for removing the particles in the processing chamber.
Preferably, the plasma processing apparatus further comprises an exhausting unit for exhausting the processing chamber.
In accordance with another aspect of the present invention, there is provided a plasma processing method of a plasma processing apparatus, comprising the steps of generating a plasma in a processing chamber in which a set processing is performed on a substrate serving as an object to be processed; and performing the processing on the substrate by the plasma, the plasma processing method further comprising the step of electrostatically driving particles in a region above the substrate to thereby be removed out of the region above the substrate in the processing chamber during the processing on the substrate.
Preferably, the plasma processing apparatus includes a mounting table for mounting the substrate; a first electrode for electrostatically adsorbing the substrate onto the mounting table; a ring-shaped member installed to enclose a periphery of the substrate; a second electrode for electrostatically adsorbing the ring-shaped member onto the mounting table; a first power supply, connected to the first electrode, for supplying an electric power with a first electric potential; and a second power supply, connected to the second electrode, for supplying an electric power with a second electric potential different from the first electric potential, wherein the mounting table, the first electrode, the ring-shaped member, and the second electrode are installed in the processing chamber, and wherein the step of driving particles includes the substep of supplying the electric power with a second electric potential different from the first electric potential to the second electrode by the second power supply.
Preferably, the step of driving particles further includes the substep of controlling at least a potential of the second electrode to remove the particles from the region above the substrate to a region above the second electrode.
Preferably, the second electric potential is higher than the first electric potential when the particles are negatively charged during the plasma processing.
Preferably, the first electric potential is of negative polarity and the second electric potential is of positive polarity.
Preferably, the first electric potential is of negative polarity and the second electric potential is of negative polarity.
Preferably, the second electric potential is higher than an electric potential formed near a surface of the substrate in the region above the substrate in response to the first electric potential or a self-bias potential formed by the generation of the plasma.
Preferably, the plasma processing method further comprises the step of removing the particles in the processing chamber.
Preferably, the plasma processing method further comprises the step of exhausting the processing chamber.
In accordance with the present invention, since the particles in the region above the substrate are electrostatically driven out of the region above the substrate in the processing chamber during the processing on the substrate by the plasma, the attachment of the particles can be inhibited, thereby preventing the contamination of the wafer. Further, the particles are removed from the region above the substrate during the plasma generation, thereby enhancing the productivity.
Still further, the second power supply supplies the electric power with a second electric potential different from the first electric potential to the second electrode for electrostatically adsorbing the ring-shaped member installed at the periphery of the substrate onto the mounting table, thereby efficiently inhibiting the attachment of the particles.
Still further, at least a potential of the second electrode is controlled to remove the particles from the region above the substrate to a region above the second electrode, thereby efficiently inhibiting the attachment of the particles.
Still further, the second electric potential is higher than the first electric potential when the particles are negatively charged during the plasma processing, thereby efficiently inhibiting the attachment of the particles.
Still further, the first electric potential is of negative polarity and the second electric potential is of positive polarity, thereby efficiently inhibiting the attachment of the particles.
Still further, the second electric potential is higher than an electric potential formed near a surface of the substrate in the region above the substrate in response to the first electric potential or a self-bias potential formed by the generation of the plasma, thereby efficiently inhibiting the attachment of the particles.
Still further, the particles are removed in the processing chamber, thereby efficiently inhibiting the attachment of the particles.
Still further, the processing chamber is exhausted, thereby efficiently inhibiting the attachment of the particles.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and features of the present invention will become apparent from the following description of preferred embodiments, given in conjunction with the accompanying drawings, in which:
FIG. 1 shows a cross sectional view schematically illustrating a configuration of a plasma processing apparatus in accordance with a preferred embodiment of the present invention;
FIG. 2 provides a graph representing a relation between an electric power for generating a plasma and the number of particles;
FIG. 3 describes an electric potential distribution formed in the processing chamber 100 shown in FIG. 1 ;
FIG. 4 exemplarily illustrates particle trajectories in a plasma region under a potential distribution represented by equipotential lines in FIG. 3 ;
FIG. 5A exemplarily depicts particle trajectories observed from an observation system shown in FIG. 7 ; and FIG. 5B is a partial enlarged view of FIG. 5A ;
FIG. 6 presents a graph showing a relation between the number of the particles observed as in FIGS. 5A and 5B and a voltage applied to an ESC electrode 122 a for FR adsorption;
FIG. 7 schematically shows a configuration of the observation system for observing the particles to obtain the experimental results described in FIGS. 5A , 5 B and 6 ; and
FIG. 8 schematically illustrates a configuration of the conventional plasma processing apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a cross sectional view schematically illustrating a configuration of a plasma processing apparatus in accordance with a preferred embodiment of the present invention.
A plasma processing apparatus shown in FIG. 1 includes a processing chamber 100 which is a cylindrical container for a prearranged plasma-using processing (hereinafter, referred to as “plasma processing”), e.g., an etching, a sputtering or a CVD (chemical vapor deposition), to be performed on a semiconductor wafer (hereinafter, referred to as “wafer”) functioning as an object to be processed; and is configured as, for example, a parallel-plate type CCP (capacitively coupled plasma) processing apparatus.
The processing chamber 100 includes a chamber sidewall 110 , an upper electrode 111 installed at the top of the chamber, a lower electrode 112 installed in a lower portion of the processing chamber 100 , an ESC (electrostatic chuck) stage 120 (mounting table) mounted on an upper side of the lower electrode 112 , and an annular shaped baffle plate 130 interposed between the chamber sidewall 110 and the lower electrode 112 .
In addition, to the outside of the processing chamber 100 is connected a gas exhaust line made of a tube-shaped member, and pumps such as a turbo molecular pump TMP and a dry pump DP are installed in the gas exhaust line. The pumps evacuate the processing chamber 100 via the baffle plate 130 , exhausting gas containing particles by using a waste gas scrubber. Further, these pumps can be installed in the chamber sidewall 110 not via the baffle plate 130 but via a valve that can be freely opened and closed.
The upper electrode 111 , which has a plurality of through holes not shown in the drawing, serves as a shower head for introducing a process gas for the plasma processing into the processing chamber 100 through the through holes. The lower electrode 112 is connected to a high frequency power supply 113 for providing a high frequency (RF: radio frequency) power.
The ESC stage 120 includes a focus ring (FR) 121 mounted on an upper side thereof; a wafer-adsorbing ESC electrode 120 a (first electrode) embedded in the ESC stage 120 for electrostatically adsorbing the mounted wafer onto the ESC stage 120 ; and an FR-adsorbing ESC electrode 122 a (second electrode) embedded in the ESC stage 120 for electrostatically adsorbing the focus ring 121 onto the ESC stage 120 . The focus ring 121 is made of a ring-shaped member formed to enclose the wafer mounted on the upper side of the ESC stage 120 .
The FR-adsorbing ESC electrode 122 a is connected via an LPF (low pass filter) to an FR-adsorbing variable power supply 122 (second power supply) for providing a power required to adsorb the focus ring 121 onto the FR-adsorbing ESC electrode 122 a . The wafer-adsorbing ESC electrode 120 a is connected via an LPF (low pass filter) to a variable power supply 125 (first power supply) for providing a power required to adsorb the wafer onto the FR-adsorbing ESC electrode 122 a . These LPFs are necessary because the ESC electrodes 120 a and 122 a are provided with an RF power generated by a capacitive coupling between the RF power supplied to the lower electrode 112 and the RF power supplied to the ESC electrode 120 a and 122 a through an insulted region in the ESC stage 120 . The variable power supplies 122 and 125 are connected to a voltage control unit, which will be described later.
The plasma processing apparatus performs a plasma processing such as an etching on an oxide film already formed on an upper side of the wafer by using, for example, a plasma generated under an intermediate vacuum level. To generate the plasma, a high frequency (RF) electric field is generated in a space between the upper electrode 111 and the lower electrode 112 by providing an RF power to the lower electrode 112 . (A plasma generating unit.) The plasma thus generated forms a plasma region in the processing chamber 100 as shown in FIG. 1 .
The particles detached from places such as an inner wall on the chamber sidewall and the like float around in the processing chamber 100 , especially in the plasma region thereof. The particles, floating in the plasma region, attract electrons contained in the plasma to thereby become negatively charged.
As shown in FIG. 1 , a bulk plasma region, which is a central portion of the plasma region, has a positive polarity relative to a reference voltage 0 V of the upper electrode 111 and a substantially constant high electric potential (voltage). On the contrary, an ion sheath region (Ion Sheath, Dark Space), which is formed near the wafer surface in a region above the wafer, forms a large potential gradient due to the influence of an electrostatic force of the lower electrode 112 and the electric potential of the bulk plasma region. Thus, the electric potential of the ion sheath region is lower than the bulk plasma region, and the polarity thereof is negative. Further, a potential gradient is formed in a plasma periphery region, i.e., the plasma region excluding the bulk plasma region.
Therefore, the particles negatively charged by attracting the electrons in the plasma tend to float around in an upper part of the ion sheath region (the region above the wafer) within the plasma periphery region, because of a balance between the gravity pulling down the particles vertically and the upwardly repelling force generated by a potential gradient formed over a range from the negatively polarized ion sheath region to the positively polarized plasma periphery region, i.e., a potential difference between the surface of the lower electrode 112 and the bulk plasma region as well as an attractive force toward the positively polarized bulk plasma region.
FIG. 2 provides a graph representing a relation between a plasma power for generating plasma and the number of particles.
In FIG. 2 , “plasma power” of the horizontal axis represents power consumption [W] calculated from the voltage and current applied to the high frequency power supply 113 for generating the plasma; and “number of particles” of the vertical axis represents the number of the particles observed in the processing chamber 100 when different voltages are applied to the high frequency power supply 113 , i.e., the number of the particles detached from the chamber sidewall 110 .
As shown in FIG. 2 , the number of the particles decreases as the plasma power increases. This is because the electrostatic force of the generated plasma gets stronger as the plasma power gets higher so that the particles are efficiently exhausted from the region above the wafer. Therefore, it is preferable that the voltage applied to the high frequency power supply 113 for generating the plasma is high and the plasma power ranges from 100 W to 4000 W.
FIG. 3 describes an electric potential distribution formed in the processing chamber 100 shown in FIG. 1 .
As shown in FIG. 3 , in the plasma processing apparatus, an electric potential distribution represented by the electric force lines, i.e., dotted lines and the equipotential lines, i.e., solid lines is formed in the processing chamber 100 when electric powers of different voltages are applied to the ESC electrodes 120 a and 122 a , respectively. Further, the electric force lines represent the case where the electric potential of the power applied to the wafer-adsorbing ESC electrode 120 a (first potential) is lower than that applied to the focus ring 121 (second potential).
Further, the turn-on and turn-off of the power is controlled by the voltage control unit (sequential control unit) shown in FIG. 1 as follows.
In case of turning on the power, the voltage control unit turns on the power to the wafer-adsorbing ESC electrode 120 a after the RF power for generating the plasma is turned on, e.g., after 1 second therefrom; and then, turns on the power to the FR-adsorbing ESC electrode 122 a after a predetermined time within a range of, for example, 0 to 100 msec. (The voltage control unit.) Further, in case of turning off the power, the voltage control unit turns off the power to the FR-adsorbing ESC electrode 122 a ; subsequently turns off the power to the wafer-adsorbing ESC electrode 120 a after a predetermined time within a range of, for example, 0 to 100 msec; and then, turns off the RF power after, e.g., 1 second therefrom. Thus, the potential distribution shown in FIG. 3 can be formed in the processing chamber 100 while the atmosphere in the processing chamber 100 is electrostatically stable, but not while the atmosphere in the processing chamber 100 is electrostatically unstable, namely, right after the plasma is generated or the plasma is extinguished.
The voltage control unit has been described to control the turn-on and turn-off of the power application to the wafer-adsorbing ESC electrode 120 a . However, the voltage control unit may well be able to control the voltage of the power to be applied to the FR-adsorbing ESC electrode 122 a while it monitors the power application to the wafer-adsorbing ESC electrode 120 a.
As shown in the equipotential lines described above, during the plasma processing, the focus ring 121 and the wafer is electrostatically adsorbed respectively onto high-voltage parts and low-voltage parts of the ESC stage 120 . Further, the particles negatively charged by attracting the electrons contained in the plasma are also attracted under the influence of the electrostatic force towards high-voltage regions.
FIG. 4 exemplarily illustrates particle trajectories in a plasma region in case of such potential distribution represented by equipotential lines shown in FIG. 3 . Further, FIG. 5A exemplarily depicts particle trajectories observed from an observation system that will be described in FIG. 7 , and FIG. 5B is a partial enlarged view thereof.
As depicted by the particle trajectories in the plasma region (the region above the wafer) in FIGS. 4 , 5 A and 5 B, when the potential distribution represented by the equipotential lines as shown in FIG. 3 is formed, the particles floating in the plasma region are driven out of the region above the wafer to somewhere above the focus ring 121 under the influence of the electrostatic force to be attracted towards the high-voltage region. (A particle moving unit.) To remove the particles efficiently, the potential of the FR-adsorbing ESC electrode 122 a is preferably higher than the potential of the wafer-adsorbing ESC electrode 120 a ; and more preferably, higher than the potential formed in response thereto near the upper side of the wafer or the self-bias potential formed by the plasma generation.
Further, as shown in FIGS. 5A and 5B , the particle trajectories near the wafer are closely spaced in the horizontal direction, and those above the focus ring 121 are spread widely in the horizontal direction. This shows that the particles are accelerated from a place above the wafer to another place above the focus ring. This is because the particles get accelerated by being repelled by the potential difference between the self-bias potential of the ion sheath region and the potential of the plasma periphery region, i.e., the region between the surface of the lower electrode 112 and the bulk plasma region and, at the same time, attracted by a high potential of the FR-adsorbing ESC electrode 122 a.
Furthermore, preferably, the potential of the FR-adsorbing ESC electrode 122 a is of polarity opposite to that of the self-bias potential in case of setting the ground as a reference voltage 0 V or the potential formed near the upper side of the wafer in response to the potential of the wafer-adsorbing ESC electrode 120 a in case of setting the ground as a reference voltage 0 V; in other words, of positive polarity. Thus, the potential of the FR-adsorbing ESC electrode 122 a can easily be made higher than the self-bias potential or the potential formed near the upper side of the wafer in response to the potential of the wafer-adsorbing ESC electrode 120 a , thereby a force attracting the particles onto somewhere above the focus ring 121 can be ensured to be generated.
FIG. 6 presents a graph showing a relation between the number of the particles observed as in FIGS. 5A and 5B and a voltage applied to an ESC electrode 122 a for FR adsorption. Further, FIG. 6 exemplifies a measurement result of the number of the particles observed by the observation system 600 shown in FIG. 7 , which will be described later.
In FIG. 6 , “voltage applied to focus ring” of the horizontal axis represents the voltage applied to the FR-adsorbing ESC electrode 122 a in case where the voltage applied to the wafer-adsorbing ESC electrode 120 a (hereinafter, referred to as “voltage applied to the wafer”) is constant at 0 V that is the reference voltage of the ground. Therefore, the voltage applied to the focus ring also represents a relative potential difference with respect to the voltage applied to the wafer (hereinafter, referred to as “relative potential difference”).
As shown in FIG. 6 , if the voltage applied to the focus ring is higher than the voltage applied to the wafer (for example, the voltage applied to the focus ring is +200 V, i.e., the relative potential difference is +200 V), the number of the particles over the wafer is small but the number of the particles over the focus ring 121 is large. On the contrary, if the voltage applied to the focus ring is not higher than the voltage applied to the wafer (for example, the voltage applied to the focus ring is 0 V, −120V, or −150 V, i.e., the relative potential difference is 0 V, −120V, or −150 V), the number of the particles over the wafer is large but the number of the particles over the focus ring 121 is small.
Further, as shown in FIG. 6 , the number of the particles over the wafer decreases and that over the focus ring 121 increases as the relative potential difference increases. Preferably, if the relative potential difference is +150 V or higher, the number of the particles over the wafer can certainly be made smaller than that over the focus ring 121 .
Referring to FIGS. 3 to 6 , by setting the potential of the power supplied to the wafer-adsorbing ESC electrode 120 a lower than the potential of the power supplied to the FR-adsorbing ESC electrode 122 a , the number of the particles in the region above the wafer during the plasma processing, especially the number of the particles in the plasma periphery region and the ion sheath region, i.e., the particles in somewhere between the bulk plasma region and the wafer surface, is reduced, thereby the attachment of the particles can be suppressed to thereby prevent the wafer contamination.
Further, since the particles in the region above the wafer during the plasma processing are driven out of the region above the wafer, the effect described hereinafter can be achieved.
By reducing the particles effectively masking the portion to be processed on the wafer, the plasma processing can be carried out without being obstructed by the particles, thereby the yield can be increased and thus the productivity can be enhanced.
Since the number of particles over the wafer can be reduced during the plasma processing, a cleaning operation of the processing chamber performed before the plasma processing can be facilitated; and, more specifically, the cleaning cycle can be extended, the seasoning time after a wet cleaning can be shortened, and, further, the start-up time of the plasma processing apparatus can be shortened. As a result, the operation time of the plasma processing apparatus can be increased, thereby significantly enhancing the productivity.
FIG. 7 schematically shows a configuration of the observation system for observing the particles to obtain the experimental results described in FIGS. 5A , 5 B and 6 .
In FIG. 7 , the observation system 600 includes a laser light source 610 , which is of SHG-YAG laser, for applying a laser beam with a wavelength of 532 nm onto the particles in the processing chamber 100 , and an image-enhancement type CCD camera 620 for imaging the inside of the processing chamber 100 . Furthermore, in the observation system 600 , a half-wave plate 611 , lenses 612 and 613 , slits 614 and 615 , and a light extinction device 616 are arranged in this order along the light path from the laser light source 610 to apply laser light scattering method. Between the slits 614 and 615 is inserted the processing chamber 100 (see FIG. 4 ). A beam of light, scattered by the particles in the processing chamber 100 , enters the CCD camera 620 via an interference filter 621 used for the light with a wavelength of 532 nm.
In the plasma processing apparatus shown in FIG. 1 , if the plasma is extinguished by stopping the power application to the ESC electrodes 120 a and 122 a after completing the plasma processing, the particles in the processing chamber 100 are removed because the plasma chamber 100 is exhausted via the baffle plate 130 by the exhaust pumps. (A particle removing unit, an exhausting unit.) Further, the exhausting process can be carried out during the plasma processing.
Since the exhaust pumps evacuate via the baffle plate 130 in the lower portion of the processing chamber 100 , the exhausting efficiency is generally low in the region near the wafer surface. However, as described with reference to FIGS. 3 to 6 , the particle removing efficiency of the exhaust pumps can be enhanced because the particles are moved to a region where the exhausting efficiency of the pump is high, i.e., towards a region above the focus ring 121 near the baffle plate 130 , during the plasma processing. Therefore, we can make it sure that the particles are prevented from being attached onto the upper surface of the wafer after the plasma extinction.
In the plasma processing apparatus in accordance with the preferred embodiment, the plasma to be generated was exemplified as a CCP generated by an RF power. However, other kinds of plasma such as an ICP (inductive coupled plasma) generated by an RF power or a UHF (ultrahigh frequency plasma) generated by a microwave can also be used therein.
The plasma processing apparatus in accordance with the preferred embodiment of the present invention can be applied to plasma-used processes such as an etching process, a sputtering process, and a CVD process.
While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims. | There is provided a plasma processing apparatus including a plasma generating unit for generating a plasma in a processing chamber in which a set processing is performed on a substrate serving as an object to be processed. The plasma processing apparatus further includes a particle moving unit for electrostatically driving particles in a region above the substrate to be removed out of the region above the substrate in the processing chamber while the processing on the substrate is performed by using the plasma. In addition, there is provided a plasma processing method of a plasma processing apparatus including the steps of generating plasma in a processing chamber in which a set processing is performed on a substrate serving as an object to be processed; and performing the processing on the substrate by the plasma. | 7 |
RELATED APPLICATIONS
[0001] This application claims the benefit of the earlier filing date under 35 U.S.C. §119(e) of U.S. Provisional Application Ser. No. 62/217,800 (filed 2015 Sep. 11).
FIELD
[0002] The invention relates to a measuring system and method for measuring the amplification and noise figure of a device under test.
BACKGROUND
[0003] Spectrum analyzers can be used for determining a noise figure of components like amplifiers or mixers. A known method for determining the noise figure is the so called Y-method, which is for example shown in the document US 2005/0137814 A1. This method comprises connecting a diode, such as an Enhanced Noise Ratio diode (ENR-diode) to the device under test (DUT) and successively switching between a regular noise signal and an enhanced noise signal. The spectrum analyzer then measures the noise power level in both situations and can determine the noise figure and the amplification factor of the DUT therefrom. The accuracy of the measuring system though is strongly influenced by a noise figure of the employed measuring device (e.g., the employed spectrum analyzer). For reducing the noise figure of the measuring device, it is suggested to use a low noise pre-amplifier (LNA). It is thereby possible to significantly reduce the noise figure of the measuring system. This, however, also leads to a reduction of the available dynamic range. Especially in broadband applications, it is possible to overpower the first stage of the analyzer with the power of the pre-amplified measuring signal.
[0004] What is needed, therefore, is a measuring system and measuring method that allow for a very accurate measurement of the noise figure and amplification of a device under test, independent of the power of the measuring signal.
SOME EXAMPLE EMBODIMENTS
[0005] Embodiments of the present invention advantageously address the foregoing requirements and needs, as well as others, by providing a measuring system and measuring method that allow for a very accurate measurement of the noise figure and amplification of a device under test, independent of the power of the measuring signal.
[0006] In accordance with example embodiments, a measuring system comprises a noise source configured to provide a noise signal to a device under test, and a measuring device configured to measure a measuring signal generated by the device under test in response to the noise signal. The measuring device comprises a signal splitter configured to split the measuring signal into at least a first split measuring signal and a second split measuring signal. The measuring device further comprises a correlator configured to correlate a signal derived from the first split measuring signal and a signal derived from the second split measuring signal. The measuring device further comprises a processor configured to determine one or more of an amplification factor and a noise figure of the device under test based on the correlated signal derived from the first split measuring signal and derived from the second split measuring signal. It is thereby possible to significantly reduce the noise generated by the measuring setup.
[0007] According to a further embodiment, the measuring device further comprises a controller configured to control a noise temperature of the noise signal generated by the noise source. By way of example, the noise source comprises a diode, such as an ENR-diode. It is thereby very easily possible to set the desired noise level of the noise source.
[0008] According to a further embodiment, the measuring system is configured to measure the one or more of the amplification factor and the noise figure of the device under test based on a Y-method. It is thereby possible to perform the measurements with minimal hardware effort.
[0009] According to a further embodiment, the measuring system further comprises a controller configured to control the noise source to successively provide a first noise signal and a second noise signal to the device under test, wherein the first noise signal has a lower noise temperature than the second noise signal, and wherein the measuring device is configured to determine the one or more of the amplification factor and the noise figure of the device under test by successively measuring the measuring signal while the noise source provides the first noise signal to the device under test and while the noise source provides the second noise signal to the device under test. A specially accurate measurement of the amplification factor and the noise figure is thereby possible.
[0010] According to a further embodiment, the measuring device further comprises a first local oscillator, a first mixer, and a second mixer. The first local oscillator is configured to provide a first local oscillator signal to the first mixer and to the second mixer. The signal splitter is configured to provide the first split measuring signal to the first mixer, and to provide the second split measuring signal to the second mixer. The first mixer is configured to mix the first split measuring signal with the first local oscillator signal to generate a first intermediate frequency signal. The second mixer is configured to mix the second split measuring signal with the first local oscillator signal to generate a second intermediate frequency signal. It is thereby possible to generate two intermediate frequency signals, which are identical except for noise added by the measuring setup.
[0011] According to a further embodiment, the measuring device comprises an I/Q-demodulator, including a first I/Q-demodulator and a second I/Q-demodulator. The first I/Q-demodulator is configured to perform an I/Q-demodulation of the first intermediate frequency signal to generate a first demodulated signal, comprising a first demodulated I-signal and a first demodulated Q-signal. The second I/Q-demodulator is configured to perform an I/Q-demodulation of the second intermediate frequency signal to generate a second demodulated signal, comprising a second demodulated I-signal and a second demodulated Q-signal. By separately demodulating the intermediate frequency signals using the same second local oscillator signal, the resulting demodulated signals are kept identical except for the noise added by the measuring setup.
[0012] According to a further embodiment, the I/Q-demodulator comprises a second local oscillator and a phase shifter, wherein the first I/Q-demodulator comprises a third mixer and a fourth mixer, and wherein the second I/Q-demodulator comprises a fifth mixer and a sixth mixer. The second local oscillator is configured to generate a second local oscillator signal and provide it to the phase shifter. The phase shifter is configured to provide a 0° phase shifted second oscillator signal to the third mixer and the fifth mixer. The phase shifter is configured to provide a −90° phase shifted second oscillator signal to the fourth mixer and the sixth mixer. The third mixer is configured to generate the first demodulated I-signal. The fourth mixer is configured to generate the first demodulated Q-signal. The fifth mixer is configured to generate the second demodulated I-signal. The sixth mixer is configured to generate the second demodulated Q-signal. It is thereby possible to further keep the signals of the two measuring branches identical except for the noise added by the measuring setup.
[0013] According to a further embodiment, the measuring device comprises a first analog-digital-converter, a second analog-digital-converter, a third analog-digital-converter, and a fourth analog-digital-converter. The third mixer is configured to provide the first demodulated I-signal to the first analog-digital-converter. The fourth mixer is configured to provide the first demodulated Q-signal to the second analog-digital-converter. The fifth mixer is configured to provide the second demodulated I-signal to the third analog-digital-converter. The sixth mixer is configured to provide the second demodulated Q-signal to the fourth analog-digital-converter. The first analog-digital-converter is configured to digitize the first demodulated I-signal to generate a digital first demodulated I-signal. The second analog-digital-converter is configured to digitize the first demodulated Q-signal to generate a digital first demodulated Q-signal. The third analog-digital-converter is configured to digitize the second demodulated I-signal to generate a digital second demodulated I-signal. The fourth analog-digital-converter is adapted to digitize the second demodulated Q-signal to generate a digital second demodulated Q-signal. It is thereby further possible to keep the resulting signals of the two measuring paths identical except for the noise added by the measuring setup.
[0014] According to a further embodiment, the measuring device further comprises a first adder and a second adder. The first adder is configured to add the digital first demodulated I-signal and the digital first demodulated Q-signal to generate the signal derived from the first split measuring signal. The second adder is configured to add the digital second demodulated I-signal and the digital second demodulated Q-signal to generate the signal derived from the second split measuring signal.
[0015] In accordance with further example embodiments, a measuring method is provided. The measuring method comprises providing a noise signal to a device under test, by a noise source, and measuring a measuring signal generated by the device under test in reaction to the noise signal, by a measuring device. The method further comprises splitting the measuring signal into at least a first split measuring signal and a second split measuring signal, by the measuring device, correlating a signal derived from the first split measuring signal and a signal derived from the second split measuring signal, by the measuring device, and determining an amplification factor and/or a noise figure of the device under test based upon the correlated signal derived from the first split measuring signal and the signal derived from the second split measuring signal, by the measuring device. It is thereby possible to significantly reduce the effect of noise added by the measuring setup. A significantly increase in measured accuracy can thereby be reached.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numerals refer to similar elements, and in which:
[0017] FIG. 1 illustrates a block diagram of a measuring system in accordance with an example embodiment of the present invention; and
[0018] FIG. 2 depicts a flow chart illustrating a measurement process in accordance with example embodiments of the present invention.
DETAILED DESCRIPTION
[0019] Approaches for a measuring device and measuring method that allow for a very accurate measurement of the noise figure and amplification of a device under test, independent of the power of the measuring signal, are described. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention is not intended to be limited based on the described embodiments, and various modifications will be readily apparent. It will be apparent that the invention may be practiced without the specific details of the following description and/or with equivalent arrangements. Additionally, well-known structures and devices may be shown in block diagram form in order to avoid unnecessarily obscuring the invention. Further, the specific applications discussed herein are provided only as representative examples, and the principles described herein may be applied to other embodiments and applications without departing from the general scope of the present invention.
[0020] FIG. 1 illustrates a block diagram of a measuring system 1 in accordance with an example embodiment of the present invention. According to the embodiment of FIG. 1 , the measuring system 1 comprises a noise source, such as diode 10 (e.g., an Enhanced Noise Ratio diode (ENR-diode)). The diode 10 is connected to a device under test (DUT) 11 , which is not a part of the measuring system. Further, the measuring system 1 comprises a switch 12 for bypassing the device under test 11 .
[0021] The device under test 11 is connected to a measuring device 13 . By way of example, the device under test 11 is connected to a signal splitter 14 , which in turn is connected to a first mixer 15 a and a second mixer 15 b . Each of the mixers 15 a , 15 b is connected to a first local oscillator 16 . An output of the mixer 15 a is connected to one input of each of two further mixers 17 a , 17 b , and an output of the mixer 15 b is connected to one input of each of two further mixers 18 a , 18 b . A second input of each of the mixers 17 a , 17 b , 18 a , 18 b is connected to a phase shifter 20 , which is connected to a second local oscillator 19 . The outputs of each of the mixers 17 a , 17 b , 18 a , 18 b is connected to the input of a respective one of the analog-to-digital (A/D) converters 21 a , 21 b , 22 a , 22 b . The outputs of the A/D converters 21 a and 22 a are connected to an adder 23 a . The outputs of the A/D converters 21 b and 22 b are connected to an adder 23 b . The outputs of the adders 23 a and 23 b are connected to a correlator 24 , which in turn is connected to a processor 25 . The processor 25 is connected to a controller 26 , which is connected to the diode 10 .
[0022] The mixers 17 a , 18 a constitute a first I/Q-demodulator, while the mixers 17 b , 18 b constitute a second I/Q-demodulator. The first and second I/Q-demodulators and the second local oscillator 19 and the phase shifter 20 constitute a I/Q-demodulator.
[0023] For performing a measurement of one or more of an amplification factor and a noise figure of the device under test 11 , the controller 26 instructs the noise source 10 to successively emit a first noise signal and a second noise signal, the first noise signal having a lower noise temperature than the second noise signal. The device under test receives the noise signal and outputs a measuring signal in response.
[0024] The measuring signal is split by the signal splitter 14 into a first split measuring signal, which is provided to the mixer 15 a and a second split measuring signal which is provided to the mixer 15 b . The local oscillator 16 generates a first local oscillator signal LO 1 and provides it to the mixers 15 a and 15 b . The mixers 15 a , 15 b mix the first and second split measuring signal with a first local oscillator signal LO 1 and thereby generate a first and second intermediate frequency signal IF 1 , IF 2 .
[0025] The first intermediate frequency signal IF 1 is provided to the first I/Q-demodulator, and the second intermediate frequency signal IF 2 is provided to the second I/Q-demodulator. The phase shifter 20 provides a second local oscillator signal LO 2 , which is phase shifted by 0° degrees (e.g., is not phase shifted) to the mixers 17 a and 17 b . The mixers 17 a , 17 b then mix the respective intermediate frequency signals IF 1 , IF 2 with the non-phase shifted second local oscillator signal LO 2 , resulting in a first demodulated I-signal 11 and a second demodulated I-signal 12 . Further, the phase shifter 20 provides second local oscillator signal LO 2 , which is phase shifted by −90° to the mixers 18 a , 18 b . The mixers 18 a , 18 b mix the respective intermediate frequency signal IF 1 , IF 2 with the −90° phase shifted second local oscillator signal LO 2 , resulting in a first demodulated Q-signal Q 1 and a second demodulated Q-signal Q 2 .
[0026] The resulting signals I 1 , I 2 , Q 1 , Q 2 , are each handed to an A/D converter 21 a , 21 b , 22 a , 22 b , which digitize the signals. Output signals of the A/D converters 21 a , 22 a are handed to an adder 23 a which adds the signals to form the signal derived from the first split measuring signal. The output signals of the A/D converters 21 b , 22 b are handed to adder 23 b , which adds the signals to a signal derived from the second split measuring signal. The output signals of the adders 23 a , 23 b are handed to the correlator 24 , which performs a correlation of these signals. Thereby, non-matching signal components, which correspond to noise added by the measuring setup (e.g., the measuring device 13 ) are thereby removed. After this, a single resulting measuring signal is handed to the processor 25 , which determines the amplification factor and/or noise figure of the device under test 11 .
[0027] In this example embodiment, a splitting of the measuring signal into two measuring branches is shown. According to further embodiments, the measuring signal may be split into a larger number of measuring paths, whereby more than two signals are correlated. This can further reduce the noise components introduced by the measuring setup within the correlated signal.
[0028] Moreover, since this measuring setup does not use a pre-amplifier, an ideal impedance matching at the output of the device under test 11 is possible, which significantly reduces the effect of the actual power level of the measuring signal.
[0029] FIG. 2 depicts a flow chart illustrating a measurement process in accordance with example embodiments of the present invention. In a first step 100 , a noise temperature of a noise signal is set. By way of example, in a third step 102 , the noise temperature is set to a first lower noise temperature. In a second step 101 , the noise signal is supplied to a device under test. A resulting measuring signal is split into at least two split measuring signals. In a fourth step 103 , each of the split measuring signals is mixed with an identical first local oscillator signal resulting in at least two intermediate frequency signals. In a fifth step 104 , an I/Q-demodulation of the at least two intermediate frequency signals on the two measuring paths is performed. This results in at least two demodulated signals. In a sixth step 105 , the demodulated signals are correlated. By way of example, during the correlation step, signal components, which are not identical within the demodulated signals are removed. It is thereby possible, to remove noise components introduced by the measuring setup. According to a further embodiment, the demodulated signals are first digitized before being correlated. In a seventh step 106 , one or more of an amplification factor and a noise figure of the device under test is/are determined based upon the correlated signals. According to a further embodiment, after performing the sixth step, it is possible to return to the first step 100 and continue with a different noise temperature.
[0030] The embodiments of the present invention can be implemented by hardware, software, or any combination thereof. Various embodiments of the present invention may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or the like.
[0031] While example embodiments of the present invention may provide for various implementations (e.g., including hardware, firmware and/or software components), and, unless stated otherwise, all functions are performed by a CPU or a processor executing computer executable program code stored in a non-transitory memory or computer-readable storage medium, the various components can be implemented in different configurations of hardware, firmware, software, and/or a combination thereof. Except as otherwise disclosed herein, the various components shown in outline or in block form in the figures are individually well known and their internal construction and operation are not critical either to the making or using of this invention or to a description of the best mode thereof.
[0032] In the preceding specification, various embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense. | A measuring system comprises a noise source adapted to provide a noise signal to a device under test. Moreover, it comprises a measuring device adapt to measure a measuring signal generated by the device under test in reaction to the noise signal. The measuring device further comprises a signal splitter adapted to split the measuring signal into at least a first split measuring signal and a second split measuring signal. Moreover it comprises a correlator adapted to correlate a signal derived from the first split measuring signal and a signal derived from the second split measuring signal. Also the measuring device comprises a processor adapted to determine an amplification factor and/or a noise figure of the device under test based upon the correlated signal derived from the first split measuring signal and signal derived from the second split measuring signal. | 7 |
BACKGROUND OF THE INVENTION
It is often necessary to compute the square of an n-bit value. Conventional squaring circuits use a single multiplier that receives and squares the n-bit value. Unfortunately, the larger the bit length n of the value, the slower and larger the single multiplier. It is desirable to increase the squaring speed and reduce the size of the squaring circuit.
SUMMARY OF THE INVENTION
In accordance with the invention, a squaring circuit includes an input terminal that is configured to carry a k-bit input bit group representing a k-bit input value. The k-bit input bit group has a left hand m-bit portion and a right hand n-bit portion representing respective left and right hand values. A left hand squaring circuit is configured to receive the left hand m-bit portion and generate a first term bit group representing a square of the left hand value. A multiplier is configured to multiply the left hand m-bit portion and the right hand n-bit portion to generate a second term bit group representing a product of the left and right hand values. A right hand squaring circuit is configured to receive the right hand n-bit portion and generate a third term bit group representing a square of the right hand value. An adder is configured to add the second term bit group (left shifted by n+1 bit positions) to a concatenation of the first and third term bit groups. The adder generates a square of the k-bit input value based on the addition. In accordance with the invention, a method includes providing the above-described circuit.
In accordance with the invention, a method includes splitting an input bit group representing an input value into left and right hand portions representing respective left and right hand values. A first term bit group is generated representing a square of the left hand value. A second term bit group is generated representing a product of the left and right hand values. A third term bit group is generated representing a square of the right hand value. The first and third term bit groups are concatenating to provide a concatenated bit group. The concatenated bit group and the second term bit group are added to generate an output bit group representing a square of the input value.
The principles of the present invention will more fully be understood in light of the following detailed description and the accompanying claims.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a circuit in accordance with the invention.
DESCRIPTION OF THE INVENTION
The following describes the squaring of a k-bit value (A[k− 1 : 0 ]). The input bit group A[ 11 : 0 ] of 001110011010 (922 10 ), where k equals 12, is often used in this description as an explanatory example.
The bit group A[k− 1 : 0 ] is divided into a left hand m-bit portion C[m− 1 : 0 ] and a right hand n-bit portion D[n− 1 : 0 ], where the sum of m and n equals k. In the explanatory example, if m is 5 and n is 7, 001110011010 (A[ 11 : 0 ]) is split into the left hand 5-bit portion 00111 (C[ 4 : 0 ]) and the right hand 7-bit portion 0011010 (D[ 6 : 0 ]). Note that m and n can be the same integer.
The value of A[k− 1 : 0 ] is equal to (C[m− 1 : 0 ]×2 n +D[n− 1 : 0 ]). In the explanatory example, the value of 001110011010 (922 10 ) is equal to (00111×2 7 +0011010), which equals (001110000000+0011010). The value of the square of A[k− 1 : 0 ] is thus equal to (C[m− 1 : 0 ]×2 n +D[n− 1 : 0 ]) 2 , which equals (C 2 [2m− 1 : 0 ]×2 2n +2C[m− 1 : 0 ]×D[n− 1 : 0 ]×2 n +D 2 [2n− 1 : 0 ]), which equals (C 2 [2m− 1 : 0 ]×2 2n +C×D[m+n− 1 : 0 ]×2 (n+1 )+D 2 [2n− 1 : 0 ]). In the explanatory example, the value of the square of 001110011010 (922 10 ) is equal to (00111×2 7 +00,11010) 2 , which equals 00001,10001×2 14 +00,00101,10110×2 8 +0000,10101,00100), which equals 0000,11001,11110,00101,00100 (850,084 10 ).
FIG. 1 shows a circuit 100 for formulating and adding these three terms {C 2 [2m− 1 : 0 ]×2 2n , C×D[m+n− 1 : 0 ]×2 n+1 ), and D 2 [2n− 1 : 0 ]} to obtain A 2 [2k− 1 : 0 ]. The k-bit value A [k− 1 : 0 ] is provided on k-bit bus 102 [k− 1 : 0 ] which may be split into left handed bus 102 [k− 1 :n] and right handed bus 102 [n− 1 : 0 ]. Left hand squaring circuit 110 receives the m-bit value C[m− 1 : 0 ] on an m-bit bus 102 [k− 1 :n] and generates the square C 2 [2m− 1 : 0 ] on 2m-bit bus 122 [2k− 1 : 2 n]. Right hand squaring circuit 120 receives the n-bit value D[n− 1 : 0 ] on an n-bit bus 102 [n− 1 : 0 ] and provides the square D 2 [2n− 1 : 0 ] on 2n-bit bus 122 [2n− 1 : 0 ]. The concatenated bus 122 [2k− 1 : 0 ] represents the sum of the first term and the third term (hereinafter, “C 2 ||D 2 [2k− 1 : 0 ]”).
In the explanatory example, if m is 5 and n is 7, squaring circuit 110 receives the 5-bit value 00111 (7 10 )on bus 102 [ 11 : 7 ] and provides the square 00001, 10001 (49 10 ) on bus 122 [ 23 : 14 ]. Squaring circuit 120 receives the 7-bit value 0011010 (26 10 ) on 7-bit bus 102 [ 6 : 0 ] and provides the square 0000,10101,00100 (676 10 ) on bus 122 [ 13 : 0 ] 1 . The resulting bus 122 [ 23 : 0 ] carries bits 0000,11000,10000,10101,00100 (803492 10 ) which represents the sum of the first term and third term.
The second term (C×D[m+n− 1 : 0 ]×2 (n+1) ) is obtained by performing the multiplication C[m− 1 : 0 ]×D[n− 1 : 0 ]. A multiplier 130 receives its input values C[m− 1 : 0 ] and D[n− 1 : 0 ] on respective busses 102 [k− 1 :n] and 102 [n− 1 : 0 ] and provides the resulting (m+n)-bit product C×D[m+n− 1 : 0 ] redundantly on busses 132 [m+2n:n+1] and 134 [m+2n:n+1]. The weights of the bits on bus 132 [m+2n:n+1] are equal to the weights of the bits on the corresponding lines of bus 122 [m+2n:n+1]. The providing of the product to busses 132 [m+2n:n+1] and 134 [m+2n:n+1] instead of busses 132 [m+n− 1 : 0 ] and 134 [m+n− 1 : 0 ] represents a left shift by n+1 bits thereby producing the second term (C[m− 1 : 0 ]×D[n− 1 : 0 ]×2 (n+1) ).
In the explanatory example, if m is 5 and n is 7, multiplier 130 receives its inputs 00111 (7 10 ) and 0011010 (26 10 ) and provides the product 00,00101,10110 (182 10 ) on bus 132 [ 19 : 8 ] The second term is thus 00001,01101,10000,00000 (46592 10 ).
Bus 122 [n: 0 ] bypasses adders 140 and 150 and is relabeled bus 152 [n: 0 ]. The value (C 2 ||D 2 ) [n: 0 ] is provided as the least n+1 significant values A 2 [n: 0 ] of square A 2 [2k− 1 : 0 ] In the explanatory example, 101,00100 is provided on bus 152 [ 7 : 0 ].
A carry save adder 140 receives (C 2 ||D 2 ) [2k− 1 :n+1] on busses 122 [2k− 1 :n+1] and receives C×D[m+2n:n+1] redundantly on busses 132 [m+2n:n+ 1 ] and 134 [m+2n:n+1]. Carry save adder 140 provides the sum S[2k− 1 :n+1] and carry Y[2k− 1 :n+1] values, redundantly representing the value A 2 [2k− 1 :n+1], on respective busses 142 [2k− 1 :n+1] and 144 [2k− 1 :n+1].
In the explanatory example, carry save adder 140 receives 0,00011,00010,00010 and 00,00101,10110 on respective busses 122 [ 23 : 8 ] and 132 [ 19 : 8 ] and provides the respective sum and carry values 0,00011,00111,10100 and 0,00000,00000,00100 on respective busses 142 [ 23 : 8 ] and 132 [ 23 : 8 ].
A carry propagate adder 150 receives its input values S[2k− 1 :n+1] and Y[2k− 1 :n+1] on respective busses 142 [2k− 1 :n+1] and 144 [2k− 1 :n+1] and provides the resulting sum A 2 [2k− 1 :n+1] on bus 152 [2k− 1 :n+1]. Therefore, the resulting square A 2 [2k− 1 : 0 ] of input value A [k− 1 : 0 ] is represented on bus 152 [2k− 1 : 0 ].
In the explanatory example, carry propagate adder 150 receives 0,00011,00111,10100 and 0,00000,00000,00100 on busses 142 [ 23 : 8 ] and 144 [ 23 : 8 ] and provides the resulting sum 0,00011,00111,11000 on bus 152 [ 23 : 8 ]. Therefore, the resulting square 0000,11001,11110,00101,00100 (850,084 10 ) is provided on bus 152 [ 23 : 0 ]. Thus, the square of A[ 11 : 0 ] is provided on bus 152 [ 23 : 0 ].
Left hand squaring circuit 110 and right hand squaring circuit 120 generate respective values C 2 [2m− 1 : 0 ] and D 2 [2n− 1 : 0 ] relatively quickly so that the square A 2 [2k− 1 : 0 ] is provided faster than in the conventional circuit. For example, left hand squaring circuit 110 and right hand squaring circuit 120 may generate results faster than multiplier 130 . For example, left hand squaring circuit 110 and right hand squaring circuit 120 may comprise partial product bit generators feeding values into a Wallace tree adder structure or may also be look-up tables for relatively small values of m and n. For small values of m and n (e.g., 6 bits or less), the use of relatively small look up tables would result in a smaller circuit than the conventional squaring circuit. Therefore, a faster and smaller squaring circuit is provided.
Although the principles of the present invention are described with reference to a specific embodiment, this embodiment is illustrative only and not limiting. Many other applications and embodiments of the principles of the present invention will be apparent in light of this disclosure and the following claims. | A squaring circuit includes an input terminal that carries a k-bit input value. The k-bit input value has left m-bit and right (k−m)-bit portions representing respective left and right hand values. A left hand squaring circuit receives the left hand m-bit portion and generates a first term bit group representing a square of the left hand value. A multiplier multiplies the left hand m-bit portion and the right hand (k−m)-bit portion to generate a second term bit group representing a product of the left and right hand values. A right hand squaring circuit generates a third term bit group representing a square of the right hand value. An adder adds the second term bit group with a concatenation of the first and third term bit groups and generate the square of the k-bit input value. | 6 |
RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. §119 based on U.S. Provisional Application No. 60/485,713, filed Jul. 10, 2003, the entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to data communications and, more particularly, to data communications within cable modem systems.
BACKGROUND OF THE INVENTION
[0003] In cable modem systems, a cable modem termination system (CMTS) at one end of a cable network typically services multiple cable modems (CMs) connected to the cable network. CMs are generally installed locally at the end user's location, and communicate with the CMTS, which may be installed at a cable company's facility. The CMTS transmits data and messages to the CMs in a “downstream” direction and receives data bursts from the CMs in an “upstream” direction.
[0004] Data over Cable Service Interface Specification (DOCSIS) is a commonly used communications protocol that defines interface requirements for CMs. DOCSIS 2.0, for example, builds upon the capabilities of DOCSIS 1.0 and DOCSIS 1.1 and adds throughput in the upstream portion of the cable system. This increased upstream data capacity enables symmetrical and time-critical services, such as videoconferencing and peer-to-peer applications. When sharing a communication channel with a CMTS, the CMs may use modulation schemes in which the modems transmit data bursts to the CMTS during designated time intervals.
[0005] CMTSs typically receive data though a number of physical ports and further distinguish between different frequencies or “channels” of data using a number of internal receivers. Current CMTSs typically have a fixed relationship between their internal receivers and the physical ports.
[0006] Certain data communications, such as Voice over Internet Protocol (VoIP), may require data blocks to be transmitted on an upstream channel on a periodic basis, such as once in every 10 ms, 20 ms, or 30 ms time interval. The same time period may be allocated to the data communications within each time interval. It is important to use each upstream channel as fully as possible. Therefore, data blocks from different data communications may be packed together as much as possible.
[0007] CM initialization requires that certain information be communicated from the CMs to the CMTS on the upstream channels. As a result, CM initialization requires a lot of bandwidth, thereby limiting the amount of data communication that can occur on the upstream channels. In the current CM initialization process, the CMTS receives the CM's capabilities (e.g., information indicating the CM's configured class of service) in a registration message that is received near the end of the CM initialization process. In some instances, the CMTS may determine, based on these capabilities, that the CM needs to be switched from its current upstream channel to another upstream channel that is better suited to handling traffic for this particular CM. In such situations, the CM may need to be rebooted to the new upstream channel. The CM then re-performs the entire CM initialization process on the new upstream channel. This can cause significant delay to the end user(s) associated with the CM.
[0008] Accordingly, there is a need to improve the CM initialization process.
SUMMARY OF THE INVENTION
[0009] Systems and methods consistent with the principles of the invention address this and other needs by providing the CM's capabilities to the CMTS early in the CM initialization process. As such, the CMTS may switch the CM from a first upstream channel to a more appropriate upstream channel before the CM performs the entire initialization process on the first upstream channel.
[0010] In accordance with one implementation consistent with the principles of this invention as embodied and broadly described herein, a method for initializing a device in a cable modem network is provided. The method includes transmitting a discover message from the device to a CMTS on a first upstream channel, where the discover message includes information representing capabilities of the device; determining, at the CMTS, whether to switch the device to a second upstream channel based on the capabilities information in the discover message, where the determining occurs before a registration of the device; and transmitting a message to the device instructing the device to switch to the second upstream channel based on the determining.
[0011] In another implementation consistent with the principles of the invention, a system includes a first device and a second device. The first device is configured to transmit a discover message on a first upstream channel, where the discover message includes information representing capabilities of the first device. The second device is configured to receive the discover message from the first device and determine whether to switch the first device to a second upstream channel based on the capabilities information in the discover message. The second device makes the determination before a registration of the first device. The second device transmits a message to the first device instructing the first device to switch to the second upstream channel based on the determining.
[0012] In yet another implementation consistent with the principles of the invention, a method for initializing a device in a cable modem network is disclosed. The method includes receiving a discover message from the device via a first upstream channel, where the discover message includes information representing one or more capabilities of the device; determining whether to switch the device to a new upstream channel based on the one or more capabilities in the discover message; and transmitting a message to the device instructing the device to switch to the new upstream channel based on the determining. The transmitting a message to the device occurs prior to a registration of the device.
[0013] In still another implementation consistent with the principles of the invention, a network device in a cable network includes an upstream communication interface, a processing device, and a downstream communication interface. The upstream communication interface is configured to receive a message from a remote device via a first upstream channel, where the message includes information representing one or more capabilities of the remote device. The processing device is configured to determine whether to switch the remote device to a new upstream channel based on the one or more capabilities included in the received message. The downstream communication interface is configured to transmit a control message to the remote device instructing the remote device to switch to the new upstream channel based on the determining. The downstream communication interface transmits the control message prior to a registration of the remote device.
[0014] In a further implementation consistent with the principles of the invention, a method for initializing a device in a cable network is provided. The method includes generating a first message that includes one or more capabilities of the device; transmitting the first message to a remote device via a first upstream channel; and receiving, in response to the transmitting, a second message from the remote device, where the second message instructs the device to switch to a second upstream channel.
[0015] In yet a further implementation consistent with the principles of the invention, a method for initializing a device in a cable network is provided. The method includes generating a first message that includes one or more capabilities of the device; transmitting the first message to a remote device via a first upstream channel; receiving, in response to the transmitting, a second message from the remote device, where the second message instructs the device to switch to a second upstream channel; and switching the device to the second upstream channel without rebooting the device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, explain the invention. In the drawings,
[0017] FIG. 1 is a diagram of an exemplary system in which systems and methods consistent with the principles of the invention may be implemented;
[0018] FIG. 2 is a diagram of an exemplary configuration of the CMTS of FIG. 1 in an implementation consistent with the principles of the invention;
[0019] FIG. 3 is a diagram of an exemplary configuration of the CM of FIG. 1 in an implementation consistent with the principles of the invention;
[0020] FIG. 4 illustrates a conventional CM initialization process;
[0021] FIG. 5 illustrates an exemplary process for performing CM initialization according to an implementation consistent with the principles of the invention; and
[0022] FIG. 6 is a diagram of an exemplary configuration of a discover message that may be transmitted by a CM in an implementation consistent with the principles of the invention.
DETAILED DESCRIPTION
[0023] The following detailed description of implementations consistent with the present invention refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims and their equivalents.
[0024] Systems and methods consistent with the principles of the invention optimize the CM initialization process in certain situations, such as where the CMTS determines that the initializing CM is to be switched to a different upstream channel. In an exemplary implementation, the CM provides its capabilities in a DHCP discover message, which allows the CMTS to determine the CM's capabilities early in the initialization process.
Exemplary System
[0025] FIG. 1 is a diagram of an exemplary system 100 in which systems and methods consistent with the principles of the invention may be implemented. As illustrated, system 100 may include a CMTS 110 that connects to a CM 120 via a cable network 130 , a number of servers 140 - 160 , and a network 170 .
[0026] CMTS 110 may transmit data received from server(s) 140 - 160 and/or network 170 on one or more downstream channels via cable network 130 to CM 120 . CMTS 110 may also transmit data received from CM 120 to server(s) 140 - 160 and/or network 170 . CM 120 may receive downstream transmissions from CMTS 110 , process the transmissions in a well-known manner, and pass the processed transmissions on to customer premises equipment (CPE) (not shown). The CPE may include, for example, a television, a computer, a telephone, or any other type of equipment that can receive and/or send data via cable network 130 . CM 120 may further receive data from the CPE, process the data, and transmit the data on one or more upstream channels to CMTS 110 via cable network 130 .
[0027] Cable network 130 may include a coaxial or hybrid optical fiber/coaxial (HFC) cable network. CM 120 may interconnect with cable network 130 via coaxial cable/optical fiber. Servers 140 - 160 may include a dynamic host configuration protocol (DHCP) server 140 , a time of day (TOD) server 150 , and a trivial file transfer protocol (TFTP) server 160 . DHCP server 140 may provide an Internet Protocol (IP) address and any other information needed to allow CM 120 to establish IP connectivity. TOD server 150 may provide CM 120 , as well as CMTS 110 , with the current date and time. CM 120 may use this time of day information, for example, for time-stamping events. TFTP server 160 may provide CM 120 with operational configuration parameters.
[0028] Network 170 can include one or more networks of any type, such as a Public Land Mobile Network (PLMN), Public Switched Telephone Network (PSTN), local area network (LAN), metropolitan area network (MAN), wide area network (WAN), the Internet, or an intranet. The PLMN may include packet-switched sub-networks, such as, for example, General Packet Radio Service (GPRS), Cellular Digital Packet Data (CDPD), and Mobile IP sub-networks.
[0029] It will be appreciated that the number of components and their arrangement as illustrated in FIG. 1 is provided for explanatory purposes only. A typical system may include more or fewer components than are illustrated in FIG. 1 and may be connected in different ways. For example, in a typical system, hundreds or thousands of CMs may be connected to a CMTS.
Exemplary CMTS Configuration
[0030] FIG. 2 is a diagram of an exemplary configuration of CMTS 110 of FIG. 1 in an implementation consistent with the principles of the invention. As illustrated, CMTS 110 may include one or more processing units 205 , a memory 210 , a communication interface 215 , an upstream/downstream communication interface 220 , and a bus 225 . It will be appreciated that CMTS 110 may include other components (not shown) that aid in the reception, processing, and/or transmission of data.
[0031] Processing unit(s) 205 may perform data processing functions for data transmitted/received via communication interface 215 to/from servers 140 - 160 and network 170 , and data transmitted/received via upstream/downstream communication interface 220 to/from cable network 130 . Memory 210 may include Random Access Memory (RAM) that provides temporary working storage of data and instructions for use by processing unit 205 in performing control and processing functions. Memory 210 may additionally include Read Only Memory (ROM) that provides permanent or semi-permanent storage of data and instructions for use by processing unit 205 . Memory 210 can also include large-capacity storage devices, such as a magnetic and/or optical recording medium and its corresponding drive.
[0032] Communication interface 215 may include conventional circuitry well known to one skilled in the art for transmitting data to, or receiving data from, servers 140 - 160 and/or network 170 . Upstream/downstream communication interface 220 may include transceiver circuitry for transmitting data bursts on downstream channels, and receiving data bursts on upstream channels, via cable network 130 . Such transceiver circuitry may include amplifiers, filters, modulators/demodulators, interleavers, error correction circuitry, and other conventional circuitry used to convert data into radio frequency (RF) signals for transmission via cable network 130 , or to interpret data bursts received from CM 120 via cable network 130 as data symbols.
[0033] Bus 225 interconnects the various components of CMTS 110 to permit the components to communicate with one another.
Exemplary CM Configuration
[0034] FIG. 3 is a diagram of an exemplary configuration of CM 120 of FIG. 1 in an implementation consistent with the principles of the invention. As illustrated, CM 120 may include a processing unit 305 , a memory 310 , a CPE interface 315 , an upstream transmitter 320 , a downstream receiver 325 , and a bus 330 . It will be appreciated that CM 120 may include other components (not shown) that aid in the reception, processing, and/or transmission of data.
[0035] Processing unit 305 may perform data processing functions for data received via downstream receiver 325 and data transmitted via upstream transmitter 320 . Processing unit 305 may also perform data processing functions for data transmitted to and received from CPE via CPE interface 315 . Memory 310 may include a RAM that provides temporary working storage of data and instructions for use by processing unit 305 in performing control and processing functions. Memory 310 may additionally include some type of ROM that provides permanent or semi-permanent storage of data and instructions for use by processing unit 305 . Memory 310 can also include large-capacity storage devices, such as a magnetic and/or optical recording medium and its corresponding drive.
[0036] CPE interface 315 may include circuitry well known to one skilled in the art for interfacing with CPE. Upstream transmitter 320 may include circuitry for transmitting on an upstream channel. For example, upstream transmitter 320 may include amplifiers, filters, modulators, interleavers, error correction circuitry, and other circuitry used to convert data into RF signals for transmission via cable network 130 . Downstream receiver 325 may include circuitry for receiving data bursts on a downstream channel. For example, downstream receiver 325 may include amplifiers, filters, demodulators and other circuitry used to interpret data bursts received from CMTS 110 as data symbols.
[0037] Bus 330 interconnects the various components of CM 120 to permit the components to communicate with one another.
Exemplary Processing
[0038] As described above, during a conventional CM initialization process under the DOCSIS protocol, a large amount of data is typically exchanged between the initializing CM and the CMTS. When a large number of CMs connect to a CMTS, this initialization process can not only be time consuming, but can also consume a large amount of valuable upstream channel bandwidth. To better understand the advantages with respect to time and upstream channel bandwidth savings, a description of a conventional CM initialization process will be described with respect to FIG. 4 . This conventional process is described in greater detail in Data-Over-Cable Service Interface Specifications (DOCSIS) Radio Frequency Interface Specification, SP-RFIv2.0-103-021218, Cable Television Laboratories, Inc., Third Issued Release, Dec. 18, 2002, pp. 233-251, which is hereby incorporated by reference in its entirety.
[0039] Processing begins with a CM performing a physical initialization operation (act 405 ). The physical initialization operation may include, for example, scanning and synchronizing to a downstream channel, obtaining a set of transmission parameters for a possible upstream channel, and performing a ranging and ranging parameter adjustment process. The physical initialization process may also include a device class identification operation in which the CM identifies itself to the CMTS for use in provisioning.
[0040] Following the physical initialization operation, the CM establishes IP connectivity. To do so, the CM transmits a DHCP discover message to a DHCP server through the CMTS to obtain a network address and any other parameters needed to establish IP connectivity (act 410 ). The discover message requests that the DHCP server assign a network address to the CM. In some instances, the discover message may suggest values for the network address and a network address lease duration.
[0041] The DHCP server responds to the DHCP discover message by sending a DHCP offer message to the CM (act 415 ). The DHCP offer message may include an available network address. Upon receiving the DHCP offer message, the CM transmits a DHCP request (REQ) message to the DHCP server (act 420 ). The DHCP request message may request that the DHCP server allocate the offered network address to the CM. The DHCP server acknowledges the assignment of the particular network address by transmitting a DHCP acknowledgment (ACK) message to the CM (act 425 ). The DHCP acknowledgment message may also include an address of the server (e.g., a TFTP server) to be accessed for retrieving operational configuration parameters and the name of the configuration file to be read from the server.
[0042] The CM sends a time of day (TOD) request to a time of day server to obtain the current date and time (act 430 ). In response to receiving the TOD request, the time of day server transmits a time of day response to the CM that includes the current date and time (act 435 ). The CM downloads operational parameters from the TFTP server using the address and file name specified in the DHCP acknowledgment message (act 440 ).
[0043] To begin transmitting data to the network, the CM performs a registration operation. The CM sends a registration (REG) request to the CMTS (act 445 ). The registration request may include the CM's capabilities, such as its configured class of service and other operational parameters from the CM's configuration file. In response to the registration request, the CMTS records the CM capabilities transmitted in the registration request and transmits a registration reply that indicates that the CM may begin forwarding traffic to the network (act 450 ).
[0044] To verify receipt of the registration reply, the CM sends a registration acknowledgment message to the CMTS (act 455 ). The CM may then optionally initialize Baseline Privacy (BP) or Baseline Privacy Plus (BP+) operations, in a well-known manner, in those instances when the CM is provisioned to run Baseline Privacy (act 460 ).
[0045] In some instances, the CMTS may determine, based on the CM's capabilities information in the registration request, that the CM should switch to another upstream channel (e.g., one that is better suited to handle the type of traffic coming from this CM). Assume that the CMTS determines, based on the configuration information provided in the registration request, that the CM needs to be switched to a specific upstream channel (act 465 ). For example, the configuration information may indicate that the CM handles VoIP traffic. If the upstream channel to which the CM is assigned cannot handle VoIP traffic, the CMTS may send the CM an Upstream Channel Change (UCC) message or a Dynamic Channel Change (DCC) message to notify the CM that it is to switch to a new upstream channel (e.g., one that is better suited for handling VoIP traffic) (act 470 ).
[0046] In response to the UCC or DCC message, CM may have to reboot (since it has already registered with the CMTS) and processing returns to act 405 where the CM goes through the entire initialization process again on the new upstream channel. Having to reboot and go through the entire initialization process again can cause a large delay in getting the CM initialized and ready to send traffic to the network. This delay can be, for example, as long as 45 minutes, which is unacceptable to end users.
[0047] To significantly reduce this delay consistent with the principles of the invention, the CM may transmit its capabilities in the DHCP discover message. When the CM is to be switched to another channel (like in the example given above), this allows the CMTS to stop the initialization process at an early stage of the process and switch the CM to a new channel. Moreover, the CM can switch to the new channel without having to reboot thereby significantly reducing the delay associated with the conventional technique described above.
[0048] FIG. 5 illustrates an exemplary process for performing CM initialization in an implementation consistent with the principles of the invention. Similar to the conventional technique described with respect to FIG. 4 , processing may begin with a CM, such as CM 120 , performing a physical initialization operation (act 505 ). The physical initialization operation may include, for example, scanning and synchronizing to a downstream channel, obtaining a set of transmission parameters for a possible upstream channel, and performing a ranging and ranging parameter adjustment process. The physical initialization process may also include a device class identification operation in which CM 120 identifies itself to a CMTS, such as CMTS 110 , for use in provisioning.
[0049] Following the physical initialization operation, CM 120 may establish IP connectivity. To do so, CM 120 may generate and transmit a DHCP discover message to a DHCP server, such as DHCP server 140 , through CMTS 110 to obtain a network address and any other parameters needed to establish IP connectivity (act 510 ). The discover message requests that DHCP server 140 assign a network address to CM 120 . In some instances, the discover message may include information, such as suggested values for the network address and a network address lease duration. In an implementation consistent with the principles of the invention, CM 120 stores information representing its capabilities in the discover message transmitted to DHCP server 140 . In one implementation, the capabilities information is stored in the vendor class identifier field of the DHCP discover message.
[0050] FIG. 6 is a diagram of an exemplary configuration of a discover message 600 that may be transmitted by CM 120 in an implementation consistent with the principles of the invention. As illustrated, discover message 600 may include a hardware type field 610 , a hardware length field 620 , a client hardware address field 630 , a client identifier (ID) field 640 , a vendor class identifier field 650 , and a parameter request list 660 .
[0051] Hardware type field 610 may store information identifying the type of downstream receiver 325 (e.g., Ethernet) associated with CM 120 . Hardware length field 620 may store a value representing a length of the address associated with downstream receiver 325 of CM 120 . Client hardware address field 630 may store the address (e.g., a 48 bit MAC address) associated with downstream receiver 325 of CM 120 . Client identifier field 640 may store, as will be appreciated by one skilled in the art, the address information when CM 120 is in a BOUND, RENEW or REBINDING state and can respond to address resolution protocol (ARP) requests.
[0052] Vendor class identifier field 650 may include a code sub-field 652 , a length sub-field 654 , and several CM capabilities sub-fields 656 . Code sub-field 652 is generally set to a value, such as 60. Length sub-field 654 stores information identifying the length (n) of vendor class identifier field 650 . CM capabilities sub-field 656 may store values that represent CM 120 's capabilities. These capabilities can include, for example, whether CM 120 requests concatenation support from CMTS 110 , the DOCSIS version of this CM 120 , whether CM 120 requests fragmentation support from CMTS 110 , whether CM 120 requests payload header suppression support from CMTS 110 , whether CM 120 supports DOCSIS 1.1-compliant Internet gateway message protocol (IGMP), whether CM 120 supports BPI or BPI+, the number of downstream security association identifiers (SAIDs) that CM 120 can support, the number of upstream service identifiers (SIDs) that CM 120 can support, the filtering support (e.g., 802.1P filtering or 802.1Q filtering) in CM 120 , the maximum number of pre-equalizer taps per modulation interval T supported by CM 120 , the number of equalizer taps supported by CM 120 , and the dynamic channel change support of CM 120 . Other CM capabilities may also be provided. For example, the capabilities may include the CM's configured class of service, such as information indicating that the CM is VoIP-capable, data supporting capable, etc.
[0053] CM 120 may use parameter request list field 660 to request specific configuration parameters from DHCP server 140 . These configuration parameters may include, for example, a network address or an address lease duration.
[0054] Returning to FIG. 5 , CMTS 110 may record the CM capabilities from DHCP discover message 600 prior to routing discover message 600 to DHCP server 140 (act 515 ). DHCP server 140 may receive DHCP discover message 600 and respond by sending a DHCP offer message to CM 120 (act 520 ). The DHCP offer message may include an available network address. Upon receiving the DHCP offer message, CM 120 may transmit a DHCP request (REQ) message to DHCP server 140 (act 525 ). The DHCP request message may request that DHCP server 140 allocate the offered network address to CM 120 . DHCP server 140 may acknowledge the assignment of the particular network address by transmitting a DHCP acknowledgment (ACK) message to CM 120 (act 530 ). The DHCP acknowledgment message may also include an address of the server (e.g., a TFTP server 160 ) to be accessed for retrieving operational configuration parameters and the name of the configuration file to be read from server 160 .
[0055] In an implementation consistent with the principles of the invention, CMTS 110 may determine, based on the CM's capabilities information in DHCP discover message 600 , the CM's configured class of service (e.g., that CM 120 is VoIP-capable) and whether this CM 120 should switch to another upstream channel (e.g., one that is better suited to handle the type of traffic coming from this type of CM). Similar to the exemplary situation described above with respect to FIG. 4 , assume that CMTS 110 determines, based on the CM capabilities information provided in DHCP discover message 600 , that CM 120 should switch to a specific upstream channel (act 535 ). For example, the capabilities information may indicate that CM 120 handles VoIP traffic. If CMTS 110 determines that the upstream channel to which CM 120 is assigned cannot handle VoIP traffic, CMTS 110 may send CM 120 a UCC message or a DCC message to notify CM 120 that it is to switch to a new upstream channel (e.g., one that is better suited for handling VoIP traffic) (act 540 ).
[0056] In response to the UCC or DCC message, processing may return to act 505 where CM 120 may re-perform the above acts on the new upstream channel. By redirecting CM 120 to a new channel early in the CM initialization process, the large delay associated with the conventional technique described above with respect to FIG. 4 can be considerably reduced. Moreover, CM 120 need not reboot since the CM has not yet registered with CMTS 110 . The delay associated with the conventional CM initialization process can thereby be reduced, for example, to a few minutes, which is much more acceptable to end users.
CONCLUSION
[0057] Systems and methods consistent with the principles of the invention optimize the CM initialization process in situations where the CMTS determines that the initializing CM is to be switched to a different upstream channel. In an exemplary implementation, the CM provides its capabilities in a DHCP discover message, which allows the CMTS to determine the CM's capabilities early in the initialization process.
[0058] The foregoing description of exemplary embodiments of the invention provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. For example, while the above description focused on the DOCSIS protocol, it will be appreciated that implementations consistent with the invention may be applicable to other cable network protocols.
[0059] While a series of acts has been described with regard to FIG. 5 , the order of the acts may be varied in other implementations consistent with the present invention. Moreover, non-dependent acts may be implemented in parallel.
[0060] No element, act, or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one” or similar language is used.
[0061] The scope of the invention is defined by the claims and their equivalents. | A system includes a first device and a second device. The first device is configured to transmit a discover message on a first upstream channel, where the discover message includes information representing capabilities of the first device. The second device is configured to receive the discover message from the first device and determine whether to switch the first device to a second upstream channel based on the capabilities information in the discover message. The second device makes the determination before a registration of the first device. The second device transmits a message to the first device instructing the first device to switch to the second upstream channel based on a result of the determination. | 7 |
This application claims the benefit of U.S. Provisional Application No.: 60/419,051 filed Oct. 16, 2002 and incorporates the same by reference.
FIELD OF THE INVENTION
The present invention relates to the method of the preparation of the title compound, (S,S)-cis-2-benzhydryl-3-benzylaminoquinuclidine (4) which is a useful intermediate in the preparation of optically active quinuclidine analogues which have utility as non-peptide antagonists of Substance P.
BACKGROUND OF THE INVENTION
Substance P is a naturally occurring undecapeptide belonging to the tachykinin family of peptides, members of which exert prompt stimulatory action on smooth muscle tissue. Substance P is a pharmaceutical active neuropeptide that is produced in mammals and possesses a characteristic amino acid sequence that is illustrated in U.S. Pat. No. 4,680,283. A variety of substance P antagonists could be prepared from the title compound; for example, U.S. Pat. No. 5,162,339 describes Substance P antagonists of formula 2 where R 1 is methoxy and R 2 is independently selected from the group consisting of isopropyl, tert-butyl, methyl, ethyl, and sec-butyl.
These substance P antagonists can be prepared by the reductive amination of cis-2-benzhydryl-3-amino-quinuclidine 1
using the appropriate aldehyde of the formula R 3 CHO where R 3 is defined as a benzaldehyde derivative with the phenyl ring substituted with R 1 and R 2 as described above, This reductive amination may be achieved with a variety of reagents such as hydrogen in the presence of a suitable metal catalyst, sodium cyanoborohydride, sodium triacetoxyborohydride, sodium borohydride, zinc and hydrochloric acid, borane dimethylsulfide or formic acid as described, for example, in WO92/21677, WO94/10170, WO94/11368, WO94/26740, WO94/08997WO97/03984, and U.S. Pat. Nos. 5,162,339, 5,721,255, 5,939,433, and 5,939,434. An alternative strategy is the conversion of 1 to 2 by an alkylation with an appropriate electrophile as is taught, for example, in U.S. Pat. Nos. 5,807,867 and 5,939,433 and WO92/21677. A further alternative strategy for the conversions of 1 to 2 is the acylation of 1 with an activated carboxylic acid derivative followed by reduction of the resultant amide with a reagent such as lithium aluminum hydride as described in WO92/21677 and the Journal of Medicinal Chemistry, 35, 2591 (1992).
The cis-2-benzhydryl-3-amino-quinuclidine 1, which is an intermediate in the formation of 2, is available from the 3-benzylamine-2-benzhydryl-quinuclidine 4 by debenzylation with hydrogen gas and a catalyst. A process for preparing benzylamine 4 has been described by Warawa in the Journal of Medicinal Chemistry, 18, 587 (1975) and is illustrated in Scheme 1. The process starts with 3-quinuclidinone 5, available by the method of Clemo et al in the Journal of the Chemical Society (London) p1241 (1939), which is condensed with benzaldehyde to generate enone 6. In turn, this is reacted with phenylmagnesium chloride to form 2-benzhydryl-3-quinuclidinbne 3. Reductive alkylation of ketone 3 with benzylamine provides 4.
The approach is amenable to adaptation to allow access to aryl and quinuclidine analogs as described in WO92/20676 and U.S. Pat. No. 5,162,339. The use of methoxybenzylamine has been used in place of benzylamine as this allows for hydrolytic removal to afford the amine 1 as well as hydrogenolysis, as described in U.S. Pat. Nos. 5,807,867 and 5,939,433.
The use of 9-BBN to effect the imine reduction formed from the reaction of benzylamine with the ketone 3 has been advocated as this maximizes formation of the desired cis-isomer of 4. This procedure is described in the Journal of Medicinal Chemistry, 35, 2591 (1992).
In all of these examples, the materials were racemic. The separation of enantiomers has been done on compound 1, 2, or 4 by classical resolution techniques. This is illustrated by the methodology described, for example, in U.S. Pat. No. 5,138,060, where the methoxyphenyl derivative 7 is separated to provide the desired (−)-isomer by crystallization of racemic 7 with (−)-mandelic acid from ethyl acetate, purification of the salt by subsequent recrystallization from ethyl acetate, and release of, the free amine product by treatment with base. In a related procedure, N-[[2-methoxy-5-(1-methylethyl)phenyl]methyl]-2-(diphenylmethyl)-1-azabicyclo[2.2.2]octan-3-amine is resolved by use of (1R)-(−)-10-camphorsulfonic acid, as described in WO 97/03984.
Use of D -tartaric acid has been disclosed in Japanese Patent No. 07025874 by Murakami, et al. for the resolution of cis-3-amino-2-benzhydrylquinuclidine (1) in methanol. Separation of the diastereoisomers of an intermediate carbamate have also been used to obtain 1 as a single enantiomer as described in the Journal of Medicinal Chemistry, 35, 2591 (1992).
SUMMARY OF THE INVENTION
The present invention relates to a process for the preparation of (S,S)-cis-2-benzhydryl-3-benzylamino quinuclidine. The inventive process includes contacting a compound containing a mixture of R- and S-isomers and having the formula
with an effective amount of a chiral organic acid in the presence of an organic solvent and an effective amount of an organic carboxylic acid for converting the R-isomer into an acid salt of the S isomer. In accordance with the inventive method, the organic solvent employed is capable of solubilizing the compound containing the mixture of R- and S-isomers, while precipitating the acid salt. Moreover, the organic carboxylic acid employed in the inventive process is different from the chiral organic acid employed.
The contacting step mentioned above is performed such that a dynamic kinetic resolution is occurring. That is, the inventive contacting step is carried out using reactants and conditions which drive the reaction to the formation of the S isomer. In accordance with the present invention, this dynamic kinetic resolution is obtainable when an effective amount of the organic carboxylic acid is employed to solubilize the quinuclidinone and provide an acidic environment to racemize the R isomer to the S isomer. It is preferred that the organic carboxylic acid is not chiral. Preferably, at least one equivalent, of organic carboxylic acid is used, and more preferably greater than one equivalent is used relative to the quinuclidinone. Likewise, the dynamic kinetic resolution is obtainable when an effective amount of at least one equivalent, preferably greater than 1 equivalent, of the chiral organic acid is employed.
After the contacting step, the resultant acid salt is neutralized with an organic base to provide an S-isomer of a chiral ketone of the formula
Next, the chiral ketone is reacted with an organic amine in the presence of a Lewis acid to provide the corresponding imine and then the imine is reduced. In accordance with the present invention, an effective amount of the Lewis acid, preferably at least one equivalent and, more preferably, greater than one equivalent is employed for optimal converision. The inventive reaction scheme is depicted in Scheme 2 below.
In a preferred embodiment, the starting material is racemic 2-benzhydryl-3-quinuclidinone(3). In a preferred embodiment, the process starts with racemic 2-benzhydryl-3-quinuclidinone (3) prepared as described by the method of Warawa in the Journal of Medicinal Chemistry, 18, 587 (1975). When treated with L -tartaric acid; a preferred chiral organic acid, the (S)-isomer of 3 crystallized as its tartrate salt in 85-90% yield. As a resolution can only deliver a 50% yield of one isomer, the remainder being the undesired antipode, a dynamic kinetic resolution is occurring. Thus, the undesired (R)-isomer is being converted to the (S)-isomer under the reaction conditions. The solvent for the crystallization is an alcohol in which the ketone 3 is soluble, of which ethanol is preferred, in the presence of an organic carboxylic acid, of which acetic acid is preferred.
The dynamic kinetic resolution allows for losses to be minimized compared to the classical resolution approaches taught in the literature as the undesired antipode does not have to be discarded.
The optically active ketone can be recovered from this salt and utilized in a reductive alkylation with benzylamine in a process wherein the S-stereochemistry is maintained at C-2 and the S-cis-stereochemistry is largely controlled at the new carbon nitrogen bond at C-3.
The process for the asymmetric reductive alkylation with benzylamine involves 1) formation of the intermediate imine by treatment of S-3 with benzylamine in an organic solvent in the presence of an excess of a mild Lewis acid such as aluminum tri-isopropoxide or titanium tetra-isopropoxide followed by reduction of the imine in-situ with hydrogen gas over a noble metal catalyst. Without limitation, an appropriate solvent for the reaction is tetrahydrofuran and the preferred catalyst for the hydrogenation is Pt on carbon.
DETAILED DESCRIPTION
For those skilled in the art, the use of the reagents and methods used in the racemic series to prepare the amine 1, and analogs thereof, is an obvious extension. The invention comprises a dynamic resolution of the ketone 3 by formation of a salt with a chiral organic acid. As used herein a chiral organic acid is an organic carboxylic acid which has an asymmetric center and has stereoisomers, some of which are mirror images of each other (enantiomers). The chiral organic acid is also soluble in the organic solvent.
An effective amount of chiral organic acid is utilized. Preferably, at least about an equimolar amount of chiral organic acid to quinuclidinone is utilized, although an excess amount of chiral organic acid can be used; however, it is preferred that about an equimolar amount of chiral organic acid is utilized. Tartaric acid is the preferred example. An organic solvent in which the racemic ketone is soluble but in which the resultant salt precipitates is employed. Sufficient solvent is present to solubilize the quinuclidinone and the various reagents. This organic solvent is preferably an alcohol, where ethanol is the preferred alcohol, and denatured alcohol is the preferred form of ethanol.
A weak organic carboxylic acid is added to aid the salt formation. The organic carboxylic acid may be a mono carboxylic acid or a poly carboxylic acid, however, it is preferred that it is a mono carboxylic acid or dicarboxylic acid. It is especially preferred that it is a mono carboxylic acid. The carboxylic acid includes, but is not limited to: acetic acid, propionic acid, and butyric acid. The preferred acid is acetic acid.
As described hereinabove, the organic carboxylic acid utilized is present in amounts sufficient to effect salt formation and promote precipitation of the salt. Preferably, at least one equivalent of organic carboxylic acid is utilized relative to the quinuclidinone.
As used herein, the term “equivalent” as it relates to an acid, refers to that amount, especially in weight or moles that contains one atomic weight or mole, respectively, of acidic hydrogen, i.e., hydrogen that reacts with base during neutralization. For example, if the acid is a monocarboxylic acid, such as acetic acid, one mole acetic acid produces one mole (equivalent) of acid. However, if the carboxylic acid is a dicarboxylic acid, said as oxalic acid, succinic acid, and the like, one mole of the dicarboxylic acid produces 2 equivalents of acid.
Thus, if the organic acid is a monocarboxylic acid, it is preferred that at least about an equimolar amount of monocarboxylic acid relative to the quinuclidinone is utilized, while if the carboxylic acid is a dicarboxylic acid, it is preferred that on a molar basis, at least about twice as much quinuclidinone relative to dicarboxylic acid is utilized. However, it is preferred that excess amounts of organic carboxylic acid is utilized.
It is preferred that the quinuclidinone, the chiral organic acid and the organic carboxylic acid are mixed together at about ambient temperatures, although they may be mixed at temperatures as low as 0° C. up to the reflux temperature of the solvent. The reaction is allowed to proceed until precipitation of the (S)-salt isomer ceases, i.e., no more precipitation is observed.
Without wishing to be bound it is believed that the combination of the chiral organic acid with the quinuclidinone and the organic carboxylic acid promotes the dynamic kinetic resolution. More specifically, under the reaction conditions, not only is the salt of the S-isomer precipitating but the undesired R isomer is being converted to the S-isomer salt. Thus, since it is being converted to the S isomer, little, if any, of R isomer is discarded under the reaction conditions of the present invention.
In the second step of the invention, the chiral ketone S-3 is obtained from the tartrate salt by neutralization of the S isomer, e.g., S-tartaric acid salt. It is preferred that this second step is conducted in a biphasic mixture of an organic solvent and water. Suitable organic solvents include, but are not limited to: toluene, ethyl acetate, and methyl t-butyl ether. The preferred organic solvent is toluene. Appropriate bases for the neutralization reaction include, but are not limited to: sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, sodium hydroxide and potassium hydroxide. In a preferred embodiment, the salt is suspended in the biphasic solvent mixture and an aqueous solution of the base is added with cooling to maintain a temperature below 25° C. until reaching a pH of about 9. The free base of optically active S-3 is recovered from the organic layer as a solid.
Without limitation one application is described herein to illustrate that the chiral ketone S-3 can be used to prepare substance P antagonists and that racemization does not occur. For those skilled in the art, other aldehydes, reducing agents for the imine and deprotection methods can be envisioned from the literature on the racemic compounds. Step three of this scheme involves the formation of the imine with a nitrogenous organic amine, such as alkyl amine, aryl amine or arylalkyl amine. It is preferred that alkyl contains 1-6 carbon atoms, which may be branched or straight chained. Examples include methyl, ethyl, isopropyl, propyl, butyl, sec-butyl, t-butyl, isobutyl, pentyl and hexyl. The term “aryl” when used alone or in combination, is an aromatic compound containing 6, 10, 14 or 18 ring carbon atoms and up to a total of 25 carbon atoms. Examples include phenyl, napthyl, and the like. The preferred amine is benzylamine. The organic amine is reacted in the presence of a mild Lewis acid in-situ to form the imine, which is then reduced to the corresponding amine by techniques known to one of ordinary skill in the art, such by reduction over a noble metal catalyst and hydrogen. This approach avoids possible racemization during the conversion of S-3 to S-4. Imine formation in the presence of a Brnsted acid resulted in some racemization at C-2. Epimerization is not observed if a Lewis acid is used to catalyze formation of the imine and then the reduction is directly performed on the resultant mixture.
Solvents suitable for the imine formation reaction are any homogenate hydrocarbons such as methylene chloride, dichlorobenzene, chlorobenzene, dichloroethane, or other inert solvents such as ethereal solvents including, but not limited to: THF and hydrocarbons including, but not limited to: toluene. Appropriate Lewis acids include aluminum tri-isopropoxide and titanium tetra-isopropoxide. The preferred Lewis acid is aluminum tri-isoproxide. The Lewis acid is present in amounts effective to form the imine. It is preferred that the nitrogenous organic amine is present in at least about equimolar amounts to that of Ketone S-3, but an excess of amine may be present. Moreover, it is preferred that the Lewis acid is present in at least catalytic effective amounts to help convert the ketone S-3 to the imine. Preferably, Lewis acid is present in at least equimolar amounts to that of the ketone S-3, especially if the latter is the limiting reagent. The resulting imine is reduced by standard techniques, such as by using a noble metal catalyst and hydrogen. The noble metal catalysts include platinum and palladium metals on various supports. The preferred catalyst is platinum on carbon. For example, one embodied step of the inventive process is carried out by mixing S-3 and benzylamine in tetrahydrofuran as a solvent and aluminum tri-isopropoxide as the Lewis acid. The imine formation is preferably carried out at room temperature for three hours. A slurry of 5% Pt/C in tetrahydrofuran was added and the reaction is stirred under a hydrogen atmosphere at 75 psi of hydrogen pressure for 15 hours. Optically active S,S-4 was isolated from the reaction.
The above-described process of the present invention achieves a significant advantage over the conventional, classical resolution approaches. The yield of the resolution step, i.e., the first contacting step, is greater than 50%, which is the maximum that can be achieved with by a typical resolution. The undesired isomer is converted to the desired one, which is isolated from the mixture, under the reaction conditions. This results in increased throughput and cost savings. The use of the quinuclidinone as a single enantiomer allows for asymmetric synthesis of the Substance P antagonists in an optically pure form by a variety of routes and alleviates the problems associated with late stage resolutions. The problems associated with racemization during reductive amination are eliminated by the use of a Lewis acid to catalyze imine formation and in situ catalytic hydrogenation.
The process described herein is useful for preparing the S,S-cis-2-benzhydryl-3-benzyl-aminoquinuclidinone from a mixture of R and S isomers of quinuclidinone. The R isomer may be present in greater amounts or vice versa. The above process is also applicable to the formation of the title compound from racemic 2-benzhydryl-3-quinuclidinone, which typically is the usual starting material.
The product formed by the above-identified process is substantially enantiomerically pure, that is, substantially free from any other stereoisomers, i.e., the RR, RS or SR products. Preferably, it contains less than 10% impurity from the other stereoisomers, and more preferably, less than about 5% impurity from the other stereoisomers and even more preferably, less than about 1% of the other stereoisomers.
The product thus formed is also preferably substantially pure, i.e., contains less than 10% impurity and more preferably contains less than 5% impurity. However, if desired, the (S,S)-cis-2-benzyhydryl-3-benzylaminoquinuclidine thus formed can be further purified by techniques known in the art, e.g., chromatography, including HPLC preparative chromatography, and other column chromotagraphy, recrystallization and the like.
The examples that follow are intended as an illustration of certain preferred embodiments of the invention, and no limitation of the invention is implied.
EXAMPLE 1
(2S)-Benzhydryl-3-quinuclidinone L -tartaric acid salt
Racemic 2-benzhydryl-3-quinuclidinone (52.45 g, 180 mmol) was dissolved in denatured ethanol (525 ml) with acetic acid (10.4 ml, 180 mmol) and L -tartaric acid (27 g, 180 mmol) was added. The mixture was heated to reflux for 12 hours and then allowed to cool to room temperature and held for one hour. The solids were collected and dried under vacuum at 40° C. for 12 hours. The yield of the desired salt was 69.9 g, 88% of theory.
EXAMPLE 2
(2S)-Benzhydryl-3-quinuclidinone (S-3)
The L -tartaric acid salt from the previous example (69.9 g, 158 mmol) was suspended in toluene (700 ml) and cooled with an ice water bath while a saturated solution of sodium bicarbonate (500 ml) was added dropwise while maintaining a maximum temperature of 25° C. The clear, biphasic mixture was stirred for 20 minutes at 25° C. and the layers were separated. The organic layer was washed with water (100 ml), the layers were separated and the organics dried over sodium sulfate. The organics were filtered and evaporated in vacuo to provide the desired, optically active ketone as a colorless solid, 45.66 g; 99% yield. Mp 145-146° C. 1 HMR (300 MHz, CDCl 3 ) δ 1.86-2.00 (m, 4), 2.41-2.43 (m, 1), 2.54-2.59 (m, 2), 3.08 (t, 2), 3.98 (d, 1), 4.55 (d, 1), 7.17 (m, 8), 7.38-7.41 (m, 2).
EXAMPLE 3
(S,S)-2-Benzylhydryl-3-benzylamino-quinuclidine (S,S-4)
With aluminum tri-isoproxide:
Under nitrogen, (2S)-benzhydryl-3-quinuclidinone (0.50 g, 1.0 equiv, 1.72 mmol) was dissolved in anhydrous THF (2 mL). Benzylamine (0.21 mL, 1.1 equiv, 1.89 mmol) was then added followed by a solution of aluminum isopropoxide (0.42 g, 1.2 equiv, 2.06 mmol) in 2 mL of anhydrous THF. The solution was stirred for 3 hours. To this colorless solution was then added a slurry of 5% Pt/C (0.063 g, Degussa F101RA/W, ˜60% wet) in 1 mL anhydrous THF. The reaction was placed in a Parr reactor, pressurized to 75 psi H 2 and allowed to react at room temperature for 15 hours. The reaction mixture was poured into 15 mL of 2M HCl, followed by filtration, basification with 1M NaOH and extraction with 50 mL methyl tertiary butyl ether (MTBE). The MTBE layer was dried with MgSO 4 , followed by removal of solvent in vacuo leaving a white crystalline solid. This was analyzed as all cis isomer (<2% trans isomer), >99% ee (none of other enantiomer observed)
With titanium tetra-isoproxide:
(2S)-Benzhydryl-3-quinuclidinone (9.00 g, 30.9 mmol) was dissolved in 75 mL of anhydrous THF. The solution is transferred through a port to a 300 mL autoclave with the hydrogenation head secured while maintaining a positive flow of nitrogen. Through the same port on the hydrogenator head and under 300 rpm stirring benzylamine (3.7 mL, 33.9 mmol) was added followed by titanium (IV) isopropoxide (10.9 mL, 36.9 mmol). The port is closed and the autoclave is pressure tested (150 psi nitrogen) while the reaction mixture is stirred at 300 rpm. After 3.0 hours at 25° C. the pressure is released and under positive nitrogen flow a slurry of 5% Pt/C (1.13 g; 59.4% wet) in 3 mL THF is added via syringe (14-gauge needle) through the port. Additional THF (2 mL) is used to slurry remaining catalyst and added to the reaction. The port is closed and the autoclave pressurized to 75 psi with hydrogen and then slowly vented. This is repeated three times. The final hydrogen pressure is adjusted to 75 psi and the reaction mixture is hydrogenated overnight (12 hours) with the stirring maintained at 600 rpm. The vessel is then vented and subsequently pressurized with nitrogen (100 psi) and vented. The reactor is pressurized with nitrogen and vented three more times.
Under positive nitrogen flow 42 mL of ice-cold 12.4% hydrochloric acid (28 mL water+14 mL 37% HCl) is added slowly and the reaction mixture is stirred under nitrogen for 1 hour at 25° C. and 900 rpm and subsequently pressure transferred into a 250 mL Erlenmeyer flask. The hydrogenator is charged with toluene (50 mL) and 30 mL of 10% hydrochloric acid. The mixture is agitated for 30 minutes at 900 rpm and subsequently pressure transferred into an Erlenmeyer flask. The combined biphasic heterogeneous solution is filtered through a 1 cm Celite pad under vacuum to remove the Pt/C catalyst. The filter cake is further rinsed with aqueous 10% HCl (100 mL). The clear filtrate phase separates immediately and the organic layer is removed and discarded. Under stirring and cooling, 50 mL of toluene is added and the pH is adjusted to approximately 13 by slow addition of 50% NaOH (30 mL). The biphasic slurry is filtered through a 1 cm Celite pad to remove titanium salts. The filter cake is washed with toluene (2×50 mL), the layers are then separated and the toluene layer is concentrated at 80° C. until the volume of toluene is reduced to 20 mL. Then, 40 mL of n-heptane is added and the mixture is slowly cooled to 10° C. over 2-3 hours (0.5 g of seeds (˜5%) is added at 55° C.). The precipitate is filtered, washed with 40 mL toluene/n-heptane 1/6 (v/v) and dried in vacuum at 40° C. The yield of colorless solids is 7.3 g, 61 % of theory. | A process for preparing (S,S)-cis-2-benzhydryl-3-benzylaminoquinuclidine. The process includes the steps of contacting a compound containing a mixture of R- and S-isomers and having the formula
with an effective amount of a chiral organic acid in the presence of an organic solvent and an effective amount of an organic carboxylic acid for converting the R-isomer into an acid salt of the S isomer, wherein the organic solvent is capable of solubilizing the compound containing the mixture of R- and S-isomers, while precipitating the acid salt and the organic carboxylic acid is different from the chiral organic acid; neutralizing the acid salt with a base to provide an S-isomer of a chiral ketone of the formula
; and reacting the chiral ketone with an organic amine in the presence of a Lewis acid to provide the corresponding imine and reducing the imine. | 2 |
RELATED APPLICATION
[0001] The present application claims priority to, and the benefits of, U.S. Ser. No. 61/116,832, filed on Nov. 21, 2008, the entire disclosure of which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to cleaning of fabrics and textile materials, and in particular to ultrasound-based cleaning.
BACKGROUND
[0003] Fabrics and textiles are typically cleaned in washing machines that soak the fabric in generally hot, detergent-laden water with mechanical agitation. In essence, the washing machine applies mechanical energy, thermal energy, and chemical action to the soiled articles. Because chemical cleaning agents can be both expensive and environmentally unfriendly, substantial effort has been directed toward cleaning systems that use no additives—just plain water, which ideally might be reused after the washing cycle, e.g., for agriculture or, with filtration, in subsequent cleaning cycles.
[0004] Ultrasound energy offers a viable alternative to traditional detergent-based cleaning approaches, since it is capable of dislodging soils without chemical assistance. Although various deployments of ultrasound in fabric-washing equipment have been attempted, none has attained commercial acceptance. A key limitation of systems thus far proposed is the inability to ensure efficient and complete exposure of the article to adequate levels of ultrasound energy. If the ultrasound is applied with insufficient focus, the energy fluence through the fabric will be inadequate to dislodge soil. On the other hand, highly focused ultrasound may not encounter all portions of a fabric article to be cleaned, or else may require excessive washing times.
SUMMARY
[0005] In accordance with some embodiments of the present invention, substantially the entire area of a fabric article is efficiently and completely exposed to focused ultrasound. As used herein, the term “substantially” means within 10%, and ideally within 5%. In this way, the benefits of cavitation are applied to the article as a whole rather than on a “spot” basis.
[0006] Cavitation is a threshold phenomenon triggered by oscillating pressure waves. In the present context, it is caused by the interaction of the acoustic beam with micro-bubbles in the fluid. Cavitation involves two mechanisms: streaming cavitation, in which gas micro-bubbles stream as a result of the acoustic beam generating high shear forces, and inertial cavitation, in which micro-bubbles implode and generate extremely high temperatures and pressures at the micron level. Initiating cavitation requires the existence of micro-bubbles in the fluid. Generating micro-bubbles typically requires a very high cavitation threshold. It is, however, possible to significantly reduce the generation threshold (also called nucleation threshold) for micro-bubbles by actively nucleating the fluid with micro-bubbles. The average diameter of the micro-bubbles desirably is smaller than the resonance radius, which depends on parameters such as the acoustic frequency, fluid parameters, temperature, pressure, etc. The following simplified equation describes the relationship among the resonance radius R 0 , the resonance frequency f 0 , the ambient pressure P 0 , the polytropic exponent of gas κ, and the density ρ of the liquid:
[0000]
f
0
=
1
2
π
3
κ
P
0
ρ
·
1
R
0
[0007] A typical desired radius is ˜1 μm within a 1 MHz ultrasound field or and 10 μm in a 0.1 MHz ultrasound field.
[0008] Streaming and inertial cavitation can be used to clean fabrics. Sheer forces generated by the streaming cavitation and localized high pressures and temperatures generated by the inertial cavitation remove soil without the need for chemical additives (e.g., detergents), although it should be emphasized that systems in accordance herewith may be used with detergents in a manner that reduces their environmental impact—e.g., enabling the use of smaller amounts of traditional detergents, or enhancing the action of more environmentally friendly but less efficacious detergents so they become more acceptable to consumers or reducing the power consumption used to heat the water.
[0009] Accordingly, in one aspect, an apparatus for laundering fabric articles in accordance with the invention may include a chamber for receiving fabric articles to be laundered; a source of ultrasound energy focusing to one or more foci, each of which may be, for example, point-shaped or linear, within the chamber; and a handling system for ensuring that substantially the entireties of the fabric articles pass at least once through at least one of the foci during a cleaning cycle. The apparatus may direct an acoustic beam in the form of a pressure wave within the cavity so that it interacts with soiled fabrics in various ways, e.g., via propagation, reflection, absorption, scatter and/or cavitation.
[0010] The handling system may include a feeding mechanism (based, for example, in an Archimedes screw) to draw the articles into the chamber. In various embodiments, the apparatus further comprising means for enforcing a standing-wave condition in the cavitation chamber, e.g., by adaptively changing the frequency or phasing, or the water level. Means for introducing micro-bubbles into the cavitation chamber may also be included, so that the fabric articles are exposed to streaming and inertial cavitation.
[0011] Various other features may be included. For example, the apparatus may include comprising a sensing module to monitor the extent of cleaning. A controller, responsive to the sensing module, may cause water in the cavitation chamber to be filtered or replaced with a new or recycled volume of water. A sensing module may be employed to monitor cavitation and the controller may responsively alter acoustic power, a temporal transmission regime and/or frequency of the ultrasound energy.
[0012] In some embodiments, the cavitation chamber is cylindrical with a first portion containing an acoustic transducer with a line focus extending axially along the center of the chamber and a second portion opposed to the first portion forming a reflector. In other embodiments, the ultrasound energy is focused to multiple foci distributed within the cavitation chamber.
[0013] The apparatus may have a separate cleaning chamber, in which case the handling system transfers fabric articles from the cleaning chamber to the cavitation chamber. The cavitation chamber, in turn, may take the form of a drum having, disposed along an inner wall thereof, a series of acoustic-wave emitting plates having axial foci each at different focal depths. In some embodiments, the emitting plates have the same focal depth and a reflector with a different focal depth is set in opposition to each emitting plate.
[0014] In another aspect, an apparatus for laundering fabric articles comprises a rotatable chamber for receiving the fabric articles to be laundered, at least a portion of the chamber being substantially transparent to ultrasound energy; at least one stationary ultrasound source, surrounding the rotatable chamber, for directing ultrasound energy to different foci within the chamber; and a controller for rotating the chamber and selectively activating the at least one ultrasound source during the rotation. The apparatus may further comprise a water-handling system for introducing water into and withdrawing water from the rotatable chamber during a cleaning cycle. The controller may, for example, ensure a minimum water level during activation of the ultrasound sources.
[0015] In some embodiments, at least a portion of the rotatable chamber is substantially transparent to ultrasound energy. For example, the apparatus may comprise a plurality of circumferentially spaced-apart ultrasound sources, with the rotatable chamber equipped with a plurality of circumferentially spaced-apart windows transparent to ultrasound energy and, between the windows, segments of a material that reflects ultrasound energy. The ultrasound sources may have foci at different focal depths, or the reflective segments may each focus ultrasound to a focus different from that of the other segments.
[0016] In still another aspect, the invention relates to an apparatus for laundering fabric articles. The apparatus comprises a chamber for receiving the fabric articles to be laundered; means for directing ultrasound energy into the chamber; a handling system for drawing fabric articles through the chamber; and means for introducing micro-bubbles into the chamber, whereby the fabric articles are exposed to streaming and inertial cavitation. The micro-bubbles have sizes optimized to enhance cavitation.
[0017] In yet another aspect, the invention pertains to a method of laundering fabric articles. The method comprises the steps of receiving, in a chamber, the fabric articles to be laundered; directing ultrasound energy to one or more foci within the chamber; and handling the fabrics such that substantially the entire areas of the fabric articles pass at least once through a cavitation region during a cleaning cycle.
[0018] Still another aspect of the invention relates to a method of laundering fabric articles that involves receiving, in a chamber, the fabric articles to be laundered so the articles are submerged in a liquid; directing ultrasound energy into the chamber; drawing fabric articles through the chamber; and introducing micro-bubbles into the chamber, whereby the fabric articles are exposed to streaming and inertial cavitation.
[0019] In still another aspect of the invention, a method of laundering fabric articles comprises the steps of rotating a chamber in which the fabric articles are submerged in a liquid; and during the rotation, selectively activating a plurality of circumferentially disposed, stationary ultrasound sources around the chamber to direct ultrasound energy to different foci within the chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which:
[0021] FIG. 1 schematically illustrates a representative embodiment of the invention;
[0022] FIG. 2 schematically illustrates a representative mechanical configuration of a focused-ultrasound washing machine in accordance with the invention;
[0023] FIG. 3 is a cross-section through a representative cavitation chamber;
[0024] FIG. 4A illustrates a segment of a cylindrical cavitation chamber in accordance with another embodiment of the invention;
[0025] FIG. 4B is a cross-section through the embodiment shown in FIG. 4A ; and
[0026] FIG. 4C is a cross-section through an alternative embodiment in which the transducers remain fixed.
DETAILED DESCRIPTION
[0027] An exemplary system 100 in accordance with the present invention is illustrated in FIG. 1 . The system includes a cleaning chamber 105 that receives fabric articles to be cleaned and an amount of water sufficient to immerse the articles. A cavitation chamber 108 , which includes an ultrasound transducer 112 , is mechanically coupled to the cleaning chamber 105 such that fabric articles may be passed between the chambers 105 , 108 by a mechanical handling system (described below). In general, chambers 105 , 108 are metal, particularly where ultrasound reflections are produced as discussed below, although it is possible to coat the interior surface with a thin layer of plastic that does not interfere with energy transmission. Cleaning takes place within the cavitation chamber 108 . A conventional acoustic driver circuit 115 , under the control of a system controller 120 , operates the transducer 112 .
[0028] As further described below, the ultrasound beam is focused within the cavitation volume to trigger cavitation effects, and a source 122 of micro-bubbles, also operated by system controller 120 , saturates the fluid in the cavitation chamber with micro-bubbles having sizes (e.g., a radius smaller than the resonance radius) optimized to enhance cavitation. A sensing device 125 monitors the level of cavitation in the in chamber 108 , e.g., by means of a conventional acoustic sensor. In some embodiments, sensing device 125 also monitors the cleanliness level of the water and/or the fabrics. For example, the device 125 may measure the clarity of the water to assess whether cleaning has been completed; alternatively, the device may measure the reflectance of the fabrics. In other embodiments, a separate cleaning sensor 130 is disposed within cleaning chamber 105 , and operates by measuring water clarity or fabric reflectance (or both).
[0029] Sensing device(s) 125 , 130 are operated by conventional circuitry 133 , which supplies power to the device(s), receives sensor signals, and communicates with system controller 120 . In some embodiments, circuitry 133 receives signals (e.g., digital signals) from controller 120 periodically during a cleaning cycle and, in response, obtains readings from device(s) 125 , 130 . These readings may, for example, be in analog form, in which case circuitry 133 includes an analog-to-digital converter, which outputs a pulse train indicative of the sensed reading to controller 120 . Alternatively, the sensor(s) may be operated continuously.
[0030] Articles within cleaning chamber 105 may be subjected to mechanical agitation in order to further the cleaning process in the manner of a conventional clothes washer. A central, finned agitation post, for example, may be operated by a mechanical motion module 137 under the control of system controller 120 . Water fills cleaning chamber 105 and is drained therefrom by conventional plumbing and valves (not shown). Instead of being drained during a cleaning cycle, however, water in the cleaning chamber 105 may be filtered and recycled back into the chamber 105 by means of a recycling module 140 . The recycling module 140 is valved to the drain plumbing and contains one or more particle and/or other filters for removing soils from the water. Modules 137 , 140 are operated by system controller 120 over the course of a cleaning cycle, for example, based at least in part on feedback from the sensing device(s) 125 , 130 .
[0031] In operation, fabric articles are loaded into cleaning chamber 105 , where system controller 120 causes water to be introduced so as to fully immerse the articles. Controller 120 may thereupon direct mechanical motion module 137 to impart an initial interval of agitation, followed by water filtration and re-introduction by means of the recycling module 140 . Articles then pass into the cavitation chamber 108 , where they are subjected to focused ultrasound and subsequently discharged back into cleaning chamber 105 . During ultrasound treatment, controller 120 , via sensing device 125 , determines the level of cavitation. Controller 120 changes—or alerts the user to change—the acoustic power, temporal transmission regime and/or frequency of the energy emitted by transducer 112 to achieve the desired cleaning effect. Based on the sensed level of water cleanliness, controller 120 may, for example, cause the water to be filtered or replaced with new volume of water via recycling module 140 , and/or cause the fabrics to undergo another sonication in chamber 108 , and/or adjust the operation of transducer 112 . Finally, controller 120 causes the fabric articles in chamber 105 to undergo a conventional drain/wash/rinse cycle.
[0032] More generally, of course, it is possible to use “open-loop” approaches that do not involve feedback, based, for example, on a timer governing the stages of a cleaning cycle in terms of fixed intervals, or on visual inspection.
[0033] FIG. 2 illustrates a representative implementation of chamber 108 and its disposition within chamber 105 . The chamber 108 takes the form of a cylindrical pipe with a flared receiving end 150 . The transducer 112 (see FIG. 1 ) extends over a cleaning zone Z having a volume of, for example, 10 to 60 liters. A conical Archimedes screw 155 captures soiled fabrics within chamber 105 and feeds them into the cavitation chamber 108 . The rate at which the fabrics are fed is determined by controller 120 and depends on the level of cleaning required: for light cleaning the feed rate will be fast, while for dirty fabrics the feed rate will be low. For example, the rate may be set by controller 120 based on an initial reflectance reading from sensing device 130 . Archimedes screw 155 forces articles through the length of chamber 108 as it receives new articles from chamber 105 , and finally forces the last articles through chamber 108 by simple conveyance of water.
[0034] In the illustrated embodiment, chamber 108 is canted with respect to chamber 105 to facilitate the flow of fabrics therethrough while keeping them below the water line. Chamber 108 may be incorporated within a central agitation post for compactness of construction.
[0035] A representative cavitation chamber 108 , shown sectionally in FIG. 3 , takes the form of a short (e.g., 20 to 60 cm) cylindrical pipe divided into two portions: the upper half-cylinder portion 160 comprises an acoustic transducer with a line focus extending axially along the center of the pipe, while the lower half-cylinder portion is metallic and acts as refocusing reflector. For example, the interior surface of half-cylinder 160 may be the output surface of transducer 112 (see FIG. 1 ) which, as shown in FIG. 3 , emits ultrasound toward the center C (so that along the length of the transducer 112 , ultrasound is focused along the central axial line extending through cylinder 108 ).
[0036] Bubble-generation module 122 (see FIG. 1 ) may be used to nucleate the cavitation volume with micro-bubbles. Exposure of the fabric surface area to the ultrasound focus or, more preferably, foci is achieved by utilizing a chamber having a size and shape optimized to generate cavitation throughout its volume (or at least a large fraction of the volume). In FIG. 3 , the single line focus means that fabrics must be agitated for a sufficient time and with adequate movement in the chamber to ensure that all points pass through the linear focus. Alternatively, the reflector segment 165 may be shaped by deviating from the cylindrical surface or by tilting the cylindrical surface to create multiple focal lines through the chamber; the greater the number of ultrasound foci, the less time and agitation will be needed to ensure complete exposure of the fabric to cavitation. Alternatively or in addition, the upper half-cylinder 160 (i.e., the transducer) may be designed with multiple foci by deviating from cylindrical surface or by building it as a phased array capable of steering the beam and the focus elctronically.
[0037] In still another implementation, illustrated in FIGS. 4A and 4B , sonication occurs within the cleaning chamber 108 . One or more cylindrical sectors of the interior drum wall contain or are configured as acoustic-wave emitting plates, two of which are representatively indicated at 112 1 , 112 2 . For example, each plate 112 n may extend over the entire cylindrical height of the chamber 108 as illustrated, or instead, circumferentially adjacent plates may extend over partial but overlapping (or adjacent) portions of the cylindrical height. The plates have different axial foci, each at a different focal depth, as shown in FIG. 4B . This can be accomplished, for example, by pre-shaping the transmitting surface to focus at a point or a line or by using lenses 180 associated with each of the plates 112 1 . . . 112 n . The lenses 180 may be, for example, plastic or other suitable material.
[0038] Alternatively, on the opposite side of the drum from each emitting plate, a reflector with a different focal depth may be disposed. In still another alternative, the semicylindrical transducer 112 shown in FIG. 1 may be employed as a stationary fixture around half of the rotating chamber 108 . These arrangements can accommodate top-loading or side-loading configurations.
[0039] To avoid the need to power rotating arrays, the drum 108 can be made from an acoustically transparent material (e.g., MYLAR) or include windows 192 1 . . . 192 n , (collectively 192 ) of such material as shown in FIG. 4C . The transducers 112 1 . . . 112 n , (collectively 112 ) are arranged around a stationary fixture 195 that surrounds the drum 108 . In this way, operation of the stationary transducer segments 112 is synchronized to the rotation and orientation of the drum 108 by a conventional motor 198 , such that the segments 112 are active only when facing an acoustic window 192 of the rotating drum. Because motor 198 is operated by controller 198 , the controller can readily track the instantaneous angular positions of the windows 192 . Once again, the transducer segments 112 may have different foci or, instead, the unwindowed portions of drum 108 , which act as reflectors for ultrasound passing through opposed windows 192 , can be focused along different interior line foci.
[0040] In a representative implementation, the invention takes the form of a traditional front-loading washing machine having a static, horizontally oriented drum of radius R in which the transducer segments are mounted and, concentrically within the static drum, a smaller-diameter rotating drum for containing fabric articles to be cleaned. The interior drum has a depth L and, after loading with soiled fabric articles, the interior drum is filled with water to a height of R/2. The rotating drum has N acoustically transparent windows around its circumference (between N+1 ribs or reflective segments). But the transducer segments are disposed only around the lower semicylindrical half of the static drum.
[0041] In particular, the lower half of the external static drum surface has M<N/2 transducer segments of size L×W, each of which can be switched on independently of one another. Each of these segments has a preset focal area within the rotating interior drum. The transducer width W<2π/N, and each transducer segment is pre-focused at a predefined distance D<R/2. Preferably, one or more standing waves is induced and maintained during operation; this minimizes the input energy necessary to sustain the cleaning process. A standing wave can be created and maintained by adaptively changing the frequency or phasing, or the water level. In the representative implementation, roughly up to ⅓ of the drum surface radiates at any given time, and a given transducer segment is active for roughly ⅓ of a full rotation. Assuming a drum speed of 60 RPM, the duty cycle is 33% at most, with a burst pulse repetition rate of 1 sec. Controller 120 monitors the water level and causes water to be added as necessary, disabling the transducer segments if the water level becomes insufficient, and may also control the frequency and/or phasing to enforce a standing-wave condition.
[0042] In operation, the interior drum is rotated at a normal speed in both directions in order to cause the fabric articles to mix and change relative location within the drum. As the drum rotates, controller 120 monitors the instanteous angular position of the drum relative to the fixed transducers, and as a window begins to pass in front of a transducer segment, controller 120 activates that segment via an associated driver 115 , causing the transducer to emit an energy burst that sustains cavitation in the water above it. Controller 120 deactivates the segment when the window rotates out of alignment therewith. In general, the transducer segments are distributed symmetrically around the circumference of and, as a result, will be simultaneously active or inactive. Controller 120 integrates sonication cycles within the overall cleaning cycle for maximum effectiveness, subsequently initiating a standard drain/wash/spin cycle.
[0043] The terms and expressions employed herein are used as terms and expressions of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof. In addition, having described certain embodiments of the invention, it will be apparent to those of ordinary skill in the art that other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention. Accordingly, the described embodiments are to be considered in all respects as only illustrative and not restrictive. | Systems and methods in accordance with the invention cause substantially the entire area of a fabric article to be laundered is efficiently and completely exposed to focused ultrasound. In this way, the benefits of cavitation are applied to the article as a whole rather than on a “spot” basis. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Patent Application Ser. Nos. 60/246,689, filed Nov. 8, 2000, 60/246,707, filed Nov. 8, 2000, 60/246,708, filed Nov. 8, 2000, and 60/246,709, filed Nov. 8, 2000.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of ophthalmic solutions and their uses. In particular the invention relates to contact lens cleaning solutions, contact lens rinsing and storing solutions, solution to deliver active pharmaceutical agents to the eye, solutions for disinfecting [ophtalmic] ophthalmic devices and the like.
BACKGROUND
[0003] The present invention relates to the field of ophthalmic solutions and especially to the aspects of preservative efficacy and comfort after prolonged use. These ophthalmic solutions have been used for some period of time and are available as over the counter products. Solutions that are used in direct contact with corneal tissue such as the delivery of active pharmaceutical agent to the eye, or indirectly, such as the cleaning, conditioning or storage of devices that will come in contact with corneal tissue, such as contact lenses, there is a need to insure that these solution do not introduce sources of bacterial or other microbial infection. Thus preservatives are included to reduce the viability of microbes in the solution and to lessen the chance of contamination of the solution by the user since many of the solutions are bought, opened, used, sealed and then reused.
[0004] State of the art preservative agents include polyhexamethylene biguanide ([phmb]) PHMB, [polyquad] Polyguad™, chlorhexidine, and benzalkonium chloride, and the like, all of which at some concentration irritate corneal tissue and lead to user discomfort. Therefore, a solution that employs a given amount of a preservative agent, but which is made more effective by addition of an agent that is not a preservative agent would be desired.
SUMMARY OF THE INVENTION
[0005] The present invention relates to improved ophthalmic solutions that employ [select] B vitamins; pyridoxine and its salts; and thiamine and its salts in order to more effectively preserve solutions and to reduce the degree to which cationic preservatives will deposit on contact lenses. Ophthalmic solutions are here understood to include contact lens treatment solutions, such as cleaners, soaking solutions, conditioning solutions and lens storage solutions, as well as wetting solutions and in-eye solutions for treatment of eye conditions.
DETAILED DESCRIPTION
[0006] The solutions specifically described herein have 0.001 to about 1 percent of [select] B vitamins; pyridoxine and its salts; and thiamine and its salts in combination with other active ingredients useful in ophthalmic solutions such as tonicity agent, buffers, preservatives, surfactants, and antimicrobial agents.
[0007] The B family of vitamins includes of thiamine (B1), riboflavin (B2), [niacin] nicotinate (niacin) (B3), pantothenic acid (B5), panthenol (precursor of pantothenic acid (B5), pyridoxine (B6), and cobalamin (B12) and vitamin B factors such as dexpanthenol. While each form of B vitamin and vitamin B factor is chemically distinct, they are often found in the same nutritional sources and hence deficiency in one is often related to deficiency in a the other forms. Metabolically, they work with one another to bolster metabolism, enhance immune and nervous system function, maintain healthy skin and muscle tone, and promote cell growth and division. They may also relieve stress, depression, and cardiovascular disease. A deficiency in one B vitamin often means that intake of all B vitamins is low which is why B as a nutritional source are often provided in multivitamin or B-complex formulae.
[0008] Niacin contributes to a great number of bodily processes. Among other things niacin helps convert food into energy, build red blood cells, synthesize hormones, fatty-acids and steroids. The body uses niacin in the process of releasing energy from carbohydrates. Niacin is also needed to form fat from carbohydrates and to process alcohol. Niacin also helps regulate cholesterol.
[0009] Pyridoxine is needed to make serotonin, melatonin, and dopamine. Vitamin B-6 is an essential nutrient in the regulation of mental processes and possibly assists in mood and many other health concerns
[0010] Cobalamin is needed for normal nerve cell activity. Vitamin B-12 is also needed for DNA replication, and production of the mood-affecting substance called SAMe (S-adenosyl-L-methionine). Vitamin B-12 works with folic acid to control homocysteine levels. An excess of homocysteine, which is an amino acid (protein building block), may increase the risk of heart disease, stroke, and perhaps osteoporosis and Alzheimer's disease.
[0011] Other compounds such as folic acid or folate are active in combination with the B vitamins and are needed to synthesize DNA. DNA allows cells to replicate normally. Folic acid is especially important for the cells of a fetus when a woman is pregnant. Folic Acid is also needed to make SAMe and keep homocysteine levels in the blood from rising. Folic Acid (pteroylglutamic acid) is not active as such in the mammalian organism, but rather is enzymatically reduced to tetrahydrofolic acid (THFA), the coenzyme form. An interrelationship exists with vitamin B12 and folate methabolism that further involves vitamin B6: folate coenzymes participate in a large number of metabolic reactions in which there is a transfer of a one-carbon unit. Pantothenic Acid, also sometimes referred to as coenzyme A, is the physiologically acitive form of pantothenic acid, and serves a vital role in metabolism as a coenzyme for a variety of enzyme-catablyzed reactions involving transfer of acetyl (two-carbon) groups. Surprisingly, pantothenic acid is essential for the growth of various microorganisms, including many strains of pathogenic bacteria.
[0012] In the form of contact lens rinsing solutions and/or pharmaceutical agent delivery system the solutions will contain, in addition to the lens or the pharmaceutical agent 0.0001 to about 1.0 weight percent of one of the vitamin B forms or a vitamin B co-metabolite chosen from the group consisting of thiamine (B1), riboflavin (B2), [niacin] nicotinate (niacin) (B3), pantothenic acid (B5), panthenol (metabolic precursor of pantothenic acid (B5), pyridoxine (B6), and cobalamin (B12), folic acid, carnitine.
[0013] The preservatives that are specifically useful are cationic preservatives such as polyhexamethylene biguanide [(phmb)] (PMHB), [polyquad] Polyquad™, chlorhexidne, and benzalkonium chloride, as well as other cationic preservatives that may prove useful in the present invention as well. The cationic preservatives are used at effective amounts as preservatives, and in the instance of PHMB from 0.0001 percent by weight to higher levels of about 0.01 weight percent.
[0014] It was found that an unexpected preservative efficacy was displayed when [inositol was] Pyroxidine, thiamine, and dexpanthenol were used in conjunction with the cationic preservative. The other components of the solution are used at levels known to those skilled in the art in order to improve the wearability of lenses and when used directly in the eye, to provide increased resistance to infection. [Inositol and other simple saccharides] Pyroxidine, thiamine and dexpanthenol used in ophthalmic solutions increases preservative efficacy in certain formulations, provides increased resistance to infection in corneal tissue, in certain formulations, and improves the quality of tears in certain formulations.
[0015] The formulations may also include buffers such as phosphates, bicarbonate, citrate, borate, ACES, BES, BICINE, BIS-Tris Propane, Tris HEPES, HEPPS, imidazole, MES, MOPS, PIPES, TAPS, TES, and Tricine
[0016] Surfactants that might be employed include polysorbate surfactants, polyoxyethylene surfactants, phosphonates, saponins and polyethoxylated castor oils, but [preerrably] preferably the polyethoxylated castor oils. These surfactants are commercially available. The polyethoxylated castor oils are sold by BASF under the trademark [Cremaphor] Cremophor.
[0017] The solutions of the present invention may contain other additives including but not limited to buffers, tonicity agents, demulcents, wetting agents, preservatives, sequestering agents (chelating agents), surface active agents, and enzymes.
[0018] Other aspects include adding to the solution from 0.001 to 1 weight percent chelating agent (preferably disodium EDTA) and/or additional microbicide, (preferably 0.00001 to 0.1 or [0.00001] 0.0001 to 0.01) weight percent polyhexamethylene biquanide ([PHMBO] PHMB, N-alkyl-2-pyrrolidone, chlorhexidine, polyquaternium-1, hexetidine, bronopol, alexidine, low concentrations of hydrogen peroxide, and ophthalmologically acceptable salts thereof.
[0019] Ophthalmologically acceptable chelating agents useful in the present invention include amino carboxylic acid compounds or water-soluble salts thereof, including ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriamine pentaacetic acid, hydroxyethylethylenediaminetriacetic acid, 1,2-diaminocyclohexanetetraacetic acid, ethylene glycol bis(beta-aminoethyl ether) in N,N,N′,N′ tetraacetic acid (EGTA), aminodiacetic acid and hydroxyethylamino diacetic acid. These acids can be used in the form of their water soluble salts, particularly their alkali metal salts. Especially preferred chelating agents are the di-, tn- and tetra-sodium salts of ethylenediaminetetraacetic acid (EDTA), most preferably disodium EDTA (Disodium Edetate).
[0020] Other chelating agents such as citrates and polyphosphates can also be used in the present invention. The citrates which can be used in the present invention include citric acid and its mono-, di-, and tri-alkaline metal salts. The polyphosphates which can be used include pyrophosphates, triphosphates, tetraphosphates, trimetaphosphates, tetrametaphosphates, as well as more highly condensed phosphates in the form of the neutral or acidic alkali metal salts such as the sodium and potassium salts as well as the ammonium salt.
[0021] The pH of the solutions should be adjusted to be compatible with the eye and the contact lens, such as between 6.0 to 8.0, preferably between 6.8 to 7.8 or between 7.0 to 7.6. Significant deviations from neutral (pH 7.3) will cause changes in the physical parameters (i.e. diameter) in some contact lenses. Low pH (pH less than 5.5) can cause burning and stinging of the eyes, while very low or very high pH (less than 3.0 or greater than 10) can cause ocular damage.
[0022] The additional preservatives employed in the present invention are known, such as polyhexamethylene biguanide, N-alkyl-2-pyrrolidone, chlorhexidine, polyhexamethylenebiguanide, alexidine, polyquaternium-1, hexetidine, bronopol and a very low concentration of hydrogen peroxide, e.g., 30 to 200 ppm.
[0023] The solutions of the invention are compatible with both rigid gas permeable and hydrophilic contact lenses during storage, cleaning, wetting, soaking, rinsing and disinfection.
[0024] A typical aqueous solution of the present invention may contain additional ingredients which would not affect the basic and novel characteristics of the active ingredients described earlier, such as tonicity agents, surfactants and viscosity inducing agents, which may aid in either the lens cleaning or in providing lubrication to the eye. Suitable tonicity agents include sodium chloride, potassium chloride, glycerol or mixtures thereof The tonicity of the solution is typically adjusted to approximately 240-310 milliosmoles per kilogram solution (mOsm/kg) to render the solution compatible with ocular tissue and with hydrophilic contact lenses. In one embodiment, the solution contains 0.01 to 0.2 weight percent sodium chloride. The important factor is to keep the concentrations of such additives to a degree no greater than that would supply a chloride concentration of no greater than about 0.2 mole percent.
[0025] Suitable viscosity inducing agents can include lecithin or the cellulose derivatives such as hydroxymethylcellulose, hydroxypropylcellulose and methylcellulose in amounts similar to those for surfactants, above.
EXAMPLE 1
[0026] Formulations containing pyridoxine HCl (Spectrum) and Thiamine HCl (Fisher) were prepared in a 0.2% phosphate buffer. The solutions were made isotonic with sodium chloride and preserved with polyhexamethylene biquanide at 0.0001%. The pH was adjusted to 7.2 with either 1 N sodium hydroxide or 1 N hydrochloric acid. The in vitro microbicidal activity of the solutions was determined by exposing C. albicans to 10 ml of each solution at room temperature for 4 hours. Subsequently, an aliquot of each solution was serial diluted onto agar plates and incubated for 48 hours at elevated temperatures. At the conclusion of the incubation period the plates are examined for the development of colonies. The log reduction was determined based on a comparison to the inoculum control. The following table provides the results of the in vitro studies.
4 Hour Log Additive Reduction Pyridoxine HCl (0.5%) 2.0 Thiamine HCl 1.0 Buffer Control 0.8
[0027] The solution containing pyridoxine HCl and thiamine HCl showed an improvement in the activity against C. albicans as compared to the buffer control.
EXAMPLE 2
[0028] Formulations containing dexpanthenol were prepared in a 0.2% phosphate buffer. The solutions were made isotonic with sodium chloride and preserved with polyhexamethylene biquanide at 0.0001%. The pH was adjusted to 7.2 with either 1 N sodium hydroxide or 1 N hydrochloric acid. The in vitro microbicidal activity of the solutions was determined by exposing C. albicans to 10 ml of each solution at room temperature for 4 hours. Subsequently, an aliquot of each solution was serial diluted onto agar plates and incubated for 48 hours at elevated temperatures. At the conclusion of the incubation period the plates are examined for the development of colonies. The log reduction was determined based on a comparison to the inoculum control. The following table provides the results of the in vitro studies.
Log Reduction [Buffer] Preservative Electrolyte Additive 2.16 [none] PHMB 0.0001% none None 3.41 [Bis-Tris PHMB 0.0001% none Dexpanthenol Propane 0.2%]
[0029] This data shows that the dexpanthenol has improved preservative efficacy over a solution with a preservative alone. | The present invention relates to improved ophthalmic solutions that employ select B vitamins; pyridoxine and its salts; and thiamine and its salts in order to more effectively preserve solutions and to reduce the degree to which cationic preservatives will deposit on contact lenses. Ophthalmic solutions are here understood to include contact lens treatment solutions, such as cleaners, soaking solutions, conditioning solutions and lens storage solutions, as well as wetting solutions and in-eye solutions for treatment of eye conditions. | 2 |
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates generally to monitoring energy consumption, and more particularly, to a method and system for monitoring whether a proper amount of energy is consumed indoors.
BACKGROUND OF THE INVENTION
[0002] The peak of power consumption in a national power crisis is closely related to weather. Since the use of an air conditioner/heater increases rapidly when it is very hot or cold, the record of the national peak is updated.
[0003] When the national power crisis is followed by a large-scale blackout, the blackout may cause inconvenience and chaos, which are nearly disasters, as well as serious economic damage. Therefore, in order to prevent these problems, there is a need for a method for monitoring whether electric power is properly consumed indoors, that is, whether cooling/heating is properly performed indoors.
[0004] To determine whether a proper amount of electric power is consumed indoors, the number of people in a room should be grasped first. However, most of the existing buildings cannot grasp the number of people in a room.
[0005] In order to grasp the number of people in a room, video equipment, many proximity sensors or many infrared ray (IR) sensors are required. However, there is a problem that either of them costs a lot of money.
[0006] Therefore, there is a demand for a method for easily grasping the number of people in a room at low cost and monitoring an improper situation where much electric energy is consumed for cooling or heating when there is no people in the room.
SUMMARY OF THE INVENTION
[0007] To address the above-discussed deficiencies of the prior art, it is a primary aspect of the present invention to provide a method and system for easily grasping the number of people in a room at low cost and monitoring whether a proper amount of energy is consumed in comparison with the number of people in the room in order to prevent a waste of energy.
[0008] According to one aspect of the present invention, a method for monitoring energy consumption includes: measuring an indoor CO 2 concentration; estimating a number of people in a room based on the CO 2 concentration; grasping an amount of energy consumed indoors; and determining whether the amount of energy consumed indoors is proper or not based on the estimated number of people in the room.
[0009] The estimating may include estimating the number of people in the room based on an increase rate of the CO 2 concentration.
[0010] The estimating may include, when the increase rate of the CO 2 concentration increases after opening/closing of an entrance door is detected, estimating that the number of people in the room increases, and, when the increase rate of the CO 2 concentration decreases after opening/closing of the entrance door is detected, estimating that the number of people in the room decreases.
[0011] The method may further include measuring an indoor O 2 concentration, and the estimating may include, when (an increase rate of the CO 2 concentration)/(a reduction rate of the O 2 concentration) falls within a predetermined range, regarding a change in the increase rate of the CO 2 concentration as being caused by a change in the number of people in the room.
[0012] The method may further include, when the amount of energy consumed indoors exceeds a threshold value in comparison with the number of people in the room, outputting a warning message.
[0013] The amount of energy consumed indoors may be an amount of electric power consumed indoors.
[0014] According to another aspect of the present invention, a system for monitoring energy consumption includes: a sensor configured to measure an indoor CO 2 concentration; a measuring unit configured to measure an amount of energy consumed indoors; and a server configured to estimate a number of people in a room based on the indoor CO 2 concentration measured by the sensor, and determine whether the amount of energy consumed indoors, which is measured by the measuring unit, is proper or not based on the estimated number of people in the room.
[0015] According to exemplary embodiments of the present invention as described above, a waste of energy can be prevented by monitoring when a proper amount of energy is consumed in comparison with the number of people in a room. In addition, the number of people in the room can be easily estimated at low cost prior to determining whether energy consumption is proper or not.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:
[0017] FIG. 1 is a block diagram showing an energy consumption monitoring system according to an exemplary embodiment of the present invention;
[0018] FIG. 2 is a flowchart to explain an energy consumption monitoring method according to another exemplary embodiment of the present invention;
[0019] FIGS. 3 and 4 are views to explain a process of estimating the number of people in a room as explained in FIG. 2 in more detail; and
[0020] FIGS. 5 and 6 are views to explain a process of determining whether electric power is properly consumed indoors as explained in FIG. 2 in more detail.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Reference will now be made in detail to the embodiment of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiment is described below in order to explain the present general inventive concept by referring to the drawings.
[0022] FIG. 1 is a block diagram showing an energy consumption monitoring system according to an exemplary embodiment of the present invention. The energy consumption monitoring system according to an exemplary embodiment includes a watt-hour meter 110 , a CO 2 sensor 120 , an entrance door sensor 130 , and a monitoring server 200 , as shown in FIG. 1 .
[0023] The watt-hour meter 110 , the CO 2 sensor 120 , and the entrance door sensor 130 are all communicably connected to the monitoring server 200 . Any connecting method such as wire connection or wireless connection may be used and there is no limit to the communication method.
[0024] The watt-hour meter 110 is a device for measuring an amount of electric power consumed indoors. The watt-hour meter 110 may be a device that is directly installed by electric power corporation or may be a product that is certified by the corporation.
[0025] The CO 2 sensor 120 is a sensor which measures indoor CO 2 concentration and transmits a result of the measuring to the monitoring server 200 . The CO 2 sensor 120 may be implemented by using a single sensor or a plurality of sensors.
[0026] When the CO 2 sensor 120 is implemented by using a plurality of sensors, the sensors may be installed at proper indoor locations and the indoor CO 2 concentration may be obtained based on an average of measured results. Alternatively, different weights (Σ weights=1) may be assigned to the measured results of the different sensors. For example, a weight to be assigned to a result measured by a sensor located at the center may be greater than a weight to be assigned to a result measured by a sensor located at an edge.
[0027] The entrance door sensor 130 is a sensor for detecting opening/closing of an entrance door through which people come in or out, and the detected state of the entrance door (opening or closing) may be transmitted to the monitoring server 200 .
[0028] The monitoring server 200 estimates the number of people in a room based on the results of measuring/detecting collected by the watt-hour meter 110 , the CO 2 sensor 120 , and the entrance door sensor 130 , and monitors whether electric power is properly consumed indoors or not based on the number of people, and notifies a manager of the result.
[0029] Hereinafter, a process of monitoring indoor electric power consumption by means of the monitoring server 200 will be explained with reference to FIG. 2 . FIG. 2 is a flowchart to explain a method for monitoring energy consumption according to another exemplary embodiment of the present invention.
[0030] As shown in FIG. 2 , when opening/closing of the entrance door is detected by the entrance door sensor 130 (S 310 -Y), the monitoring server 200 measures indoor CO 2 concentration for a predetermined time (S 320 ), and estimates the number of people in the room based on the measured indoor CO 2 concentration (S 330 ).
[0031] In step S 320 , the indoor CO 2 concentration may be measured by the monitoring server 200 waking up the CO 2 sensor 120 in a sleep mode and instructing to measure the CO 2 concentration, and receiving the measured CO 2 concentration from the CO 2 sensor 120 .
[0032] In this embodiment, in step S 330 , the number of people in the room may be estimated only when the opening/closing of the entrance door is detected by the entrance door sensor 130 . A change in the number of people in the room requires that the entrance door should be opened or closed. Therefore, when the entrance door is neither opened nor closed, the number of people in the room is regarded as being maintained as it is. Accordingly, the CO 2 sensor 120 measures the CO 2 concentration only when the number of people in the room is expected to change and thus electric power consumed by the CO 2 sensor 120 can be minimized.
[0033] In step S 330 , the number of people in the room is estimated based on an increase rate of the CO 2 concentration. That is, when the increase rate of the CO 2 concentration increases, it is estimated that the number of people in the room increases, and, when the increase rate of the CO 2 concentration decreases, it is estimated that the number of people in the room decreases.
[0034] Referring to FIGS. 3 and 4 , the process of estimating the number of people in the room will be explained in more detail. FIG. 3 is a graph showing a change in indoor CO 2 .
[0035] In FIG. 3 , points of time ‘a’, ‘b’, and ‘c’ are points of time at which the entrance door is opened or closed and the number of people in the room is changed. Specifically, at the point of time ‘a’, people enter the room and thus indoor CO 2 is generated. At the point of time ‘b’, the number of people in the room increases and thus the increase rate of the indoor CO 2 concentration increases. However, at the point of time ‘c’, the number of people in the room decreases and thus the increase rate of the indoor CO 2 concentration decreases.
[0036] FIG. 4 is a graph showing the increase rate of the CO 2 concentration of FIG. 3 . It can be seen from the graph of FIG. 4 that the number of people in the room is changed with time.
[0037] Referring to FIGS. 3 and 4 , when the increase rate of the indoor CO 2 concentration increases after the opening/closing of the entrance door is detected, it is estimated that the number of people in the room increases, and, when the increase rate of the indoor CO 2 concentration decreases after the opening/closing of the entrance door is detected, it is estimated that the number of people in the room decreases.
[0038] In FIG. 3 , the graph shows the CO 2 concentration at all of the points of time. However, this is for the convenience of explanation. The monitoring server 200 is only required to grasp the increase rate of the indoor CO 2 concentration. Therefore, the indoor CO 2 concentration has only to be measured for a predetermined time after the opening/closing of the entrance door is detected. This is because the monitoring server 200 can grasp the increase rate of the indoor CO 2 concentration just by doing so.
[0039] Thereafter, the monitoring server 200 grasps an amount of electric power consumed in the room (S 340 ). In step S 340 , the amount of electric power consumed in the room may be grasped by the monitoring server 200 requesting a current status of indoor electric power consumption from the watt-hour meter 110 and receiving the current status of the indoor electric power consumption.
[0040] Next, the monitoring server 200 determines whether the amount of electric power grasped in step S 340 is proper or not based on the number of people measured in step S 330 (S 350 ).
[0041] Specifically, in step S 350 , the monitoring server 200 determines whether the amount of electric power consumed in the room exceeds a threshold value or not in comparison with the number of people in the room, and determines whether the amount of electric power consumed in the room is proper or not. As the number of people in the room decreases, the threshold value decrease, and, as the number of people in the room increases, the threshold value increases.
[0042] When it is determined that the amount of electric power consumed in the room is improper in step S 350 (S 360 -Y), the monitoring server 200 outputs a warning message to notify the manager (S 370 ). In step S 370 , the warning message may be transmitted to a terminal of the manager.
[0043] FIG. 5 illustrates a current status of electric power consumption. FIG. 6 is a graph showing FIGS. 4 and 5 altogether. As shown in FIG. 6 , the amount of electric power consumed is proper at the points of time before the point of time ‘c’ (X), but the amount of electric power consumed is improper at the points of time after the point of time ‘c’ (Y). In this state, the warning message is output in step S 370 . This is because the amount of electric power is not reduced even when the number of people in the room decreases.
[0044] Up to now, the method and system for estimating the number of people in a room based on indoor CO 2 concentration and monitoring whether electric power is properly consumed indoors based on the number of people according to an exemplary embodiment has been described.
[0045] In the above-described exemplary embodiment, the amount of electric power consumed is monitored. However, the technical idea of the present invention can be applied when an amount of other energy consumed (gas, oil, water, etc.) is monitored.
[0046] In addition, indoor O 2 concentration may be measured in addition to the indoor CO 2 concentration. This is to identify whether the increase in the CO 2 concentration is caused by the use of a CO 2 generating device such as a gas range or increase of the number of people in the room.
[0047] Specifically, a value (range) of (an increase rate of CO 2 concentration)/(a reduction rate of O 2 concentration) caused by a human's breathing is calculated, and a value (range) of (an increase rate of CO 2 concentration)(a reduction rate of O 2 concentration) caused by the use of a gas range is calculated. These values are stored in the monitoring sever 200 . It may be determined whether increase in the indoor CO 2 concentration is caused by increase in the number of people in the room or not by grasping which value (range) a change in the increase rate of the CO 2 concentration belongs to.
[0048] Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims. | A method and system for monitoring energy consumption is provided. The method for monitoring energy consumption estimates a number of people in a room based on an indoor CO 2 concentration, and determines whether an amount of energy consumed indoors is proper or not based on the estimated number of people in the room. Accordingly, a waste of energy can be prevented by monitoring when a proper amount of energy is consumed in comparison with the number of people in a room. In addition, the number of people in the room can be easily estimated at low cost prior to determining whether energy consumption is proper or not. | 5 |
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